Printed Circuit Board Assembly & PCB Design SMT Electronics Assembly Manufacturing Forum

Printed Circuit Board Assembly & PCB Design Forum

SMT electronics assembly manufacturing forum.


Off Pad Printing

JohnW

#10810

Off Pad Printing | 28 June, 1999

Hey there gang, how's it going ?

Anyway's here's my probelm, got a new product to build double sided reflow, lot's of so20's and PLcc's 1206's, 0805's the usual stuff. Probelm is all the pad spacing of the 1206's are too big, my component's are only catching the very edge of the pad's. As a consequence I'm getting them drifting to one side and hence load's of dry's since I'm getting no where near the 1 pad once it's reflowed. I've looked at the profile and even brought the ramp into reflow down to about 1 drgree per sec, I've thrown in a little bit of of silver to reduce the temps..I've even turned off the N2 to reduce the wetting force..but still I'm getting the problems. Now I know the answer is to go back and get the customer to sort out their design problems..introduce them to IPC std's and all that but they say it's gonna be a very long time before I get new cad data for better boards. So a buddy suggested off pad printing,i.e. design my stencil for the component and print onto the resit instead of the pads... Anyone have experience of this ?, and if so..how was the solderballs ??? Any other idea's would be most welcome, and before they come I've already had the following ones :- Coasters for coffee, shelf's for small books, frisbies ( man I miss them), clock's, need I go on ???

thanks in advance

JohnW

reply »

Earl Moon

#10811

Re: Off Pad Printing | 28 June, 1999

| Hey there gang, how's it going ? | | Anyway's here's my probelm, got a new product to build double sided reflow, lot's of so20's and PLcc's 1206's, 0805's the usual stuff. Probelm is all the pad spacing of the 1206's are too big, my component's are only catching the very edge of the pad's. As a consequence I'm getting them drifting to one side and hence load's of dry's since I'm getting no where near the 1 pad once it's reflowed. | I've looked at the profile and even brought the ramp into reflow down to about 1 drgree per sec, I've thrown in a little bit of of silver to reduce the temps..I've even turned off the N2 to reduce the wetting force..but still I'm getting the problems. | Now I know the answer is to go back and get the customer to sort out their design problems..introduce them to IPC std's and all that but they say it's gonna be a very long time before I get new cad data for better boards. So a buddy suggested off pad printing,i.e. design my stencil for the component and print onto the resit instead of the pads... | Anyone have experience of this ?, and if so..how was the solderballs ??? | Any other idea's would be most welcome, and before they come I've already had the following ones :- | Coasters for coffee, | shelf's for small books, | frisbies ( man I miss them), | clock's, | need I go on ??? | | thanks in advance | | JohnW | Damn John,

What a place you've found. Never tried it with big chips, but often use dogbone apertures with those smaller for similar or other reasons. Maybe it would work as well. It really is a variation on off pad printing.

Earl Moon

reply »

#10812

Re: Off Pad Printing | 28 June, 1999

| Hey there gang, how's it going ? | | Anyway's here's my probelm, got a new product to build double sided reflow, lot's of so20's and PLcc's 1206's, 0805's the usual stuff. Probelm is all the pad spacing of the 1206's are too big, my component's are only catching the very edge of the pad's. As a consequence I'm getting them drifting to one side and hence load's of dry's since I'm getting no where near the 1 pad once it's reflowed. | I've looked at the profile and even brought the ramp into reflow down to about 1 drgree per sec, I've thrown in a little bit of of silver to reduce the temps..I've even turned off the N2 to reduce the wetting force..but still I'm getting the problems. | Now I know the answer is to go back and get the customer to sort out their design problems..introduce them to IPC std's and all that but they say it's gonna be a very long time before I get new cad data for better boards. So a buddy suggested off pad printing,i.e. design my stencil for the component and print onto the resit instead of the pads... | Anyone have experience of this ?, and if so..how was the solderballs ??? | Any other idea's would be most welcome, and before they come I've already had the following ones :- | Coasters for coffee, | shelf's for small books, | frisbies ( man I miss them), | clock's, | need I go on ??? | | thanks in advance | | JohnW | John

You could try larger parts, 2010's Or if you have an adhesive dot puter outer you could place a dot of adhesive after screen printing to hold the sucker centered betwixed the pads.

MD Cox

reply »


DNC

#10813

Re: Off Pad Printing | 28 June, 1999

| Hey there gang, how's it going ? | | Anyway's here's my probelm, got a new product to build double sided reflow, lot's of so20's and PLcc's 1206's, 0805's the usual stuff. Probelm is all the pad spacing of the 1206's are too big, my component's are only catching the very edge of the pad's. As a consequence I'm getting them drifting to one side and hence load's of dry's since I'm getting no where near the 1 pad once it's reflowed. | I've looked at the profile and even brought the ramp into reflow down to about 1 drgree per sec, I've thrown in a little bit of of silver to reduce the temps..I've even turned off the N2 to reduce the wetting force..but still I'm getting the problems. | Now I know the answer is to go back and get the customer to sort out their design problems..introduce them to IPC std's and all that but they say it's gonna be a very long time before I get new cad data for better boards. So a buddy suggested off pad printing,i.e. design my stencil for the component and print onto the resit instead of the pads... | Anyone have experience of this ?, and if so..how was the solderballs ??? | Any other idea's would be most welcome, and before they come I've already had the following ones :- | Coasters for coffee, | shelf's for small books, | frisbies ( man I miss them), | clock's, | need I go on ??? | | thanks in advance | | JohnW |

Deon Response:

Hi John,

I would try the offset printing approach. Move your apertures in towards center of location in order to accomodate part leads to sit on paste. Solder balls should not be an issue, if the print does not exceed 30%-40% off pad. Another critical issue is to make sure that your placements are centered and make initial contact with the paste on both sides of pad when placed. This will help surface tension pull part in both directions once in reflow stage. Good Luck.

Regards,

Deon Nungaray SMT Mfg Engineer GMI USA CA

reply »

#10814

Re: Off Pad Printing | 28 June, 1999

| Hey there gang, how's it going ? | | Anyway's here's my probelm, got a new product to build double sided reflow, lot's of so20's and PLcc's 1206's, 0805's the usual stuff. Probelm is all the pad spacing of the 1206's are too big, my component's are only catching the very edge of the pad's. As a consequence I'm getting them drifting to one side and hence load's of dry's since I'm getting no where near the 1 pad once it's reflowed. | I've looked at the profile and even brought the ramp into reflow down to about 1 drgree per sec, I've thrown in a little bit of of silver to reduce the temps..I've even turned off the N2 to reduce the wetting force..but still I'm getting the problems. | Now I know the answer is to go back and get the customer to sort out their design problems..introduce them to IPC std's and all that but they say it's gonna be a very long time before I get new cad data for better boards. So a buddy suggested off pad printing,i.e. design my stencil for the component and print onto the resit instead of the pads... | Anyone have experience of this ?, and if so..how was the solderballs ??? | Any other idea's would be most welcome, and before they come I've already had the following ones :- | Coasters for coffee, | shelf's for small books, | frisbies ( man I miss them), | clock's, | need I go on ??? | | thanks in advance | | JohnW | John: The off pad printing you're talking about will work, but:

1 I'm concerned about the reliability of the solder connections the I envision you making. (I picture this as chip caps touching the pads on the edge of the end of their metalization only, with no side fillet or solder under the metalization.) 2 If you're going to be doing this for a "very long time," I'd like to see you ECO the boards. The ECO would (1) add conductive ink between the pads to make them the proper size for the components and (2) apply a solder mask to the undesired portion of the pads.

Either Additive or Conductive Circuits ( there was a thread on them last week on SMTnet) can do something like this easily. And I'd expect your customer gleefully give you a waiver and pay for the change, after you tell them:

1 How much the rework will cost and ... 2 Components will probably fall off the first time some drop kicks their product across the room, if they don't let you add the solder mask.

Good luck

Dave F

reply »

Earl Moon

#10815

Re: Off Pad Printing | 29 June, 1999

| | Hey there gang, how's it going ? | | | | Anyway's here's my probelm, got a new product to build double sided reflow, lot's of so20's and PLcc's 1206's, 0805's the usual stuff. Probelm is all the pad spacing of the 1206's are too big, my component's are only catching the very edge of the pad's. As a consequence I'm getting them drifting to one side and hence load's of dry's since I'm getting no where near the 1 pad once it's reflowed. | | I've looked at the profile and even brought the ramp into reflow down to about 1 drgree per sec, I've thrown in a little bit of of silver to reduce the temps..I've even turned off the N2 to reduce the wetting force..but still I'm getting the problems. | | Now I know the answer is to go back and get the customer to sort out their design problems..introduce them to IPC std's and all that but they say it's gonna be a very long time before I get new cad data for better boards. So a buddy suggested off pad printing,i.e. design my stencil for the component and print onto the resit instead of the pads... | | Anyone have experience of this ?, and if so..how was the solderballs ??? | | Any other idea's would be most welcome, and before they come I've already had the following ones :- | | Coasters for coffee, | | shelf's for small books, | | frisbies ( man I miss them), | | clock's, | | need I go on ??? | | | | thanks in advance | | | | JohnW | | | John: The off pad printing you're talking about will work, but: | | 1 I'm concerned about the reliability of the solder connections the I envision you making. (I picture this as chip caps touching the pads on the edge of the end of their metalization only, with no side fillet or solder under the metalization.) | 2 If you're going to be doing this for a "very long time," I'd like to see you ECO the boards. The ECO would (1) add conductive ink between the pads to make them the proper size for the components and (2) apply a solder mask to the undesired portion of the pads. | | Either Additive or Conductive Circuits ( there was a thread on them last week on SMTnet) can do something like this easily. And I'd expect your customer gleefully give you a waiver and pay for the change, after you tell them: | | 1 How much the rework will cost and ... | 2 Components will probably fall off the first time some drop kicks their product across the room, if they don't let you add the solder mask. | | Good luck | | Dave F | John and Dave,

Again, I don't work with larger chip devices with this issue. The company I now work with developed a strategy, based on considerable research (as others of us did in the past), to do things like placing 0603's on 0402 pad configurations. This means having very small (minimal) side, heel, toe, or any other type, filleting. This provides a mechanism for long term reliability in at least one way.

One reliabillity issue resolved is that of minimizing large solder fillets thermally and mechanically exerting excessive force on components - especially end caps. This ensures more "flexibility" (actually better mechanical force "averaging" between the device and the substrate/conductor area) as less stress is experienced during soldering operations and operational activities.

This goes back to (actually still being used in MIL applications) leadless ceramic chip carrier (LCCC) device types without constraint in the MLB construction. You may not have exactly the design you need, but something close may work very well for you. This is where "dog boning" can be useful - it can provide extra off pad solder paste printing, when required. This can be done in either of the two print directions.

Possible great discovery on your part?

Earl Moon

reply »

#10816

Re: Off Pad Printing | 29 June, 1999

snip

| John and Dave, | | Again, I don't work with larger chip devices with this issue. The company I now work with developed a strategy, based on considerable research (as others of us did in the past), to do things like placing 0603's on 0402 pad configurations. This means having very small (minimal) side, heel, toe, or any other type, filleting. This provides a mechanism for long term reliability in at least one way. | | One reliabillity issue resolved is that of minimizing large solder fillets thermally and mechanically exerting excessive force on components - especially end caps. This ensures more "flexibility" (actually better mechanical force "averaging" between the device and the substrate/conductor area) as less stress is experienced during soldering operations and operational activities. | | This goes back to (actually still being used in MIL applications) leadless ceramic chip carrier (LCCC) device types without constraint in the MLB construction. You may not have exactly the design you need, but something close may work very well for you. This is where "dog boning" can be useful - it can provide extra off pad solder paste printing, when required. This can be done in either of the two print directions. | | Possible great discovery on your part? | | Earl Moon | | Earl: I agree that large solder fillets can create reliability problems, but that�s not what we�re talking about here. In John�s case, the solder will wet the whole pad and form a fairly uniform layer of solder. It will wet the end caps. And provided the end caps are touching the pads or are close enough be bridged with solder, it will form a fillet between the pad and the end caps. I don�t agree that the solder will flow to the component side of the pad and exert excessive thermal and mechanical force on components - especially end caps.

I�m more concerned about a frail solder joint that suffers from lack of solder than one that�s over-stressed from too much material. We�re talking about how to form a solder bridge to connect the component to the pad!!!! And at best that it will only form a electrical and weak mechanical link, providing there is good metalization on the pads, equal wetting on both end caps, and the component is placed properly for the distinct pad spacing of that component.

Ya know, at the end of the day, I like Mike�s suggestion. Very nice Mike.

Ta

Dave F

reply »

Earl Moon

#10817

Re: Off Pad Printing | 30 June, 1999

| | snip | | | John and Dave, | | | | Again, I don't work with larger chip devices with this issue. The company I now work with developed a strategy, based on considerable research (as others of us did in the past), to do things like placing 0603's on 0402 pad configurations. This means having very small (minimal) side, heel, toe, or any other type, filleting. This provides a mechanism for long term reliability in at least one way. | | | | One reliabillity issue resolved is that of minimizing large solder fillets thermally and mechanically exerting excessive force on components - especially end caps. This ensures more "flexibility" (actually better mechanical force "averaging" between the device and the substrate/conductor area) as less stress is experienced during soldering operations and operational activities. | | | | This goes back to (actually still being used in MIL applications) leadless ceramic chip carrier (LCCC) device types without constraint in the MLB construction. You may not have exactly the design you need, but something close may work very well for you. This is where "dog boning" can be useful - it can provide extra off pad solder paste printing, when required. This can be done in either of the two print directions. | | | | Possible great discovery on your part? | | | | Earl Moon | | | | | Earl: I agree that large solder fillets can create reliability problems, but that�s not what we�re talking about here. In John�s case, the solder will wet the whole pad and form a fairly uniform layer of solder. It will wet the end caps. And provided the end caps are touching the pads or are close enough be bridged with solder, it will form a fillet between the pad and the end caps. I don�t agree that the solder will flow to the component side of the pad and exert excessive thermal and mechanical force on components - especially end caps. | | I�m more concerned about a frail solder joint that suffers from lack of solder than one that�s over-stressed from too much material. We�re talking about how to form a solder bridge to connect the component to the pad!!!! And at best that it will only form a electrical and weak mechanical link, providing there is good metalization on the pads, equal wetting on both end caps, and the component is placed properly for the distinct pad spacing of that component. | | Ya know, at the end of the day, I like Mike�s suggestion. Very nice Mike. | | Ta | | Dave F | Dave,

You're too kind. I can almost see the light now, but maybe not as well as if you could suggest another two or ten books on the subject for me to read.

Keep me/us straight,

Earl Moon

reply »

#10818

Re: Off Pad Printing | 30 June, 1999

| | | | snip | | | | | John and Dave, | | | | | | Again, I don't work with larger chip devices with this issue. The company I now work with developed a strategy, based on considerable research (as others of us did in the past), to do things like placing 0603's on 0402 pad configurations. This means having very small (minimal) side, heel, toe, or any other type, filleting. This provides a mechanism for long term reliability in at least one way. | | | | | | One reliabillity issue resolved is that of minimizing large solder fillets thermally and mechanically exerting excessive force on components - especially end caps. This ensures more "flexibility" (actually better mechanical force "averaging" between the device and the substrate/conductor area) as less stress is experienced during soldering operations and operational activities. | | | | | | This goes back to (actually still being used in MIL applications) leadless ceramic chip carrier (LCCC) device types without constraint in the MLB construction. You may not have exactly the design you need, but something close may work very well for you. This is where "dog boning" can be useful - it can provide extra off pad solder paste printing, when required. This can be done in either of the two print directions. | | | | | | Possible great discovery on your part? | | | | | | Earl Moon | | | | | | | | Earl: I agree that large solder fillets can create reliability problems, but that�s not what we�re talking about here. In John�s case, the solder will wet the whole pad and form a fairly uniform layer of solder. It will wet the end caps. And provided the end caps are touching the pads or are close enough be bridged with solder, it will form a fillet between the pad and the end caps. I don�t agree that the solder will flow to the component side of the pad and exert excessive thermal and mechanical force on components - especially end caps. | | | | I�m more concerned about a frail solder joint that suffers from lack of solder than one that�s over-stressed from too much material. We�re talking about how to form a solder bridge to connect the component to the pad!!!! And at best that it will only form a electrical and weak mechanical link, providing there is good metalization on the pads, equal wetting on both end caps, and the component is placed properly for the distinct pad spacing of that component. | | | | Ya know, at the end of the day, I like Mike�s suggestion. Very nice Mike. | | | | Ta | | | | Dave F | | | Dave, | | You're too kind. I can almost see the light now, but maybe not as well as if you could suggest another two or ten books on the subject for me to read. | | Keep me/us straight, | | Earl Moon | Thanks Dave

Me thinks I have spent way too many years in the contract world. Working with non CE/DFM designs, you learn to improvise and do what ever it takes to put those itsy bitsy parts on green boards.

MD Cox

reply »

Earl Moon

#10819

Re: Off Pad Printing | 30 June, 1999

| | | | | | snip | | | | | | | John and Dave, | | | | | | | | Again, I don't work with larger chip devices with this issue. The company I now work with developed a strategy, based on considerable research (as others of us did in the past), to do things like placing 0603's on 0402 pad configurations. This means having very small (minimal) side, heel, toe, or any other type, filleting. This provides a mechanism for long term reliability in at least one way. | | | | | | | | One reliabillity issue resolved is that of minimizing large solder fillets thermally and mechanically exerting excessive force on components - especially end caps. This ensures more "flexibility" (actually better mechanical force "averaging" between the device and the substrate/conductor area) as less stress is experienced during soldering operations and operational activities. | | | | | | | | This goes back to (actually still being used in MIL applications) leadless ceramic chip carrier (LCCC) device types without constraint in the MLB construction. You may not have exactly the design you need, but something close may work very well for you. This is where "dog boning" can be useful - it can provide extra off pad solder paste printing, when required. This can be done in either of the two print directions. | | | | | | | | Possible great discovery on your part? | | | | | | | | Earl Moon | | | | | | | | | | | Earl: I agree that large solder fillets can create reliability problems, but that�s not what we�re talking about here. In John�s case, the solder will wet the whole pad and form a fairly uniform layer of solder. It will wet the end caps. And provided the end caps are touching the pads or are close enough be bridged with solder, it will form a fillet between the pad and the end caps. I don�t agree that the solder will flow to the component side of the pad and exert excessive thermal and mechanical force on components - especially end caps. | | | | | | I�m more concerned about a frail solder joint that suffers from lack of solder than one that�s over-stressed from too much material. We�re talking about how to form a solder bridge to connect the component to the pad!!!! And at best that it will only form a electrical and weak mechanical link, providing there is good metalization on the pads, equal wetting on both end caps, and the component is placed properly for the distinct pad spacing of that component. | | | | | | Ya know, at the end of the day, I like Mike�s suggestion. Very nice Mike. | | | | | | Ta | | | | | | Dave F | | | | | Dave, | | | | You're too kind. I can almost see the light now, but maybe not as well as if you could suggest another two or ten books on the subject for me to read. | | | | Keep me/us straight, | | | | Earl Moon | | | Thanks Dave | | Me thinks I have spent way too many years in the contract world. Working with non CE/DFM designs, you learn to improvise and do what ever it takes to put those itsy bitsy parts on green boards. | | MD Cox | | | MD,

Yeah, and it's so much more rewarding working harder instead of smarter not forgetting how much fun it is to bitch about poor designs, fabs, solder masks, no time with the family, and STUPID MANAGEMENT (that's us included folks!) while having a very small forum to voice our considerable, learned over all that time you mentioned, knowledge and experience. Any of this ring a bell or are we all punch drunk? I certainly can answer for myself in the affirmative.

Moonman

reply »

Mcox

#10820

Re: Off Pad Printing | 30 June, 1999

| | | | | | | | snip | | | | | | | | | John and Dave, | | | | | | | | | | Again, I don't work with larger chip devices with this issue. The company I now work with developed a strategy, based on considerable research (as others of us did in the past), to do things like placing 0603's on 0402 pad configurations. This means having very small (minimal) side, heel, toe, or any other type, filleting. This provides a mechanism for long term reliability in at least one way. | | | | | | | | | | One reliabillity issue resolved is that of minimizing large solder fillets thermally and mechanically exerting excessive force on components - especially end caps. This ensures more "flexibility" (actually better mechanical force "averaging" between the device and the substrate/conductor area) as less stress is experienced during soldering operations and operational activities. | | | | | | | | | | This goes back to (actually still being used in MIL applications) leadless ceramic chip carrier (LCCC) device types without constraint in the MLB construction. You may not have exactly the design you need, but something close may work very well for you. This is where "dog boning" can be useful - it can provide extra off pad solder paste printing, when required. This can be done in either of the two print directions. | | | | | | | | | | Possible great discovery on your part? | | | | | | | | | | Earl Moon | | | | | | | | | | | | | | Earl: I agree that large solder fillets can create reliability problems, but that�s not what we�re talking about here. In John�s case, the solder will wet the whole pad and form a fairly uniform layer of solder. It will wet the end caps. And provided the end caps are touching the pads or are close enough be bridged with solder, it will form a fillet between the pad and the end caps. I don�t agree that the solder will flow to the component side of the pad and exert excessive thermal and mechanical force on components - especially end caps. | | | | | | | | I�m more concerned about a frail solder joint that suffers from lack of solder than one that�s over-stressed from too much material. We�re talking about how to form a solder bridge to connect the component to the pad!!!! And at best that it will only form a electrical and weak mechanical link, providing there is good metalization on the pads, equal wetting on both end caps, and the component is placed properly for the distinct pad spacing of that component. | | | | | | | | Ya know, at the end of the day, I like Mike�s suggestion. Very nice Mike. | | | | | | | | Ta | | | | | | | | Dave F | | | | | | | Dave, | | | | | | You're too kind. I can almost see the light now, but maybe not as well as if you could suggest another two or ten books on the subject for me to read. | | | | | | Keep me/us straight, | | | | | | Earl Moon | | | | | Thanks Dave | | | | Me thinks I have spent way too many years in the contract world. Working with non CE/DFM designs, you learn to improvise and do what ever it takes to put those itsy bitsy parts on green boards. | | | | MD Cox | | | | | | | MD, | | Yeah, and it's so much more rewarding working harder instead of smarter not forgetting how much fun it is to bitch about poor designs, fabs, solder masks, no time with the family, and STUPID MANAGEMENT (that's us included folks!) while having a very small forum to voice our considerable, learned over all that time you mentioned, knowledge and experience. Any of this ring a bell or are we all punch drunk? I certainly can answer for myself in the affirmative. | | Moonman | Yeper

You got that s__t right. But tonight all of that will change, at 9pm MST I will be the next Power Ball winner. That�s right folks, I will be 145 million dollars richer. Then I will build the perfect contract manufacturing plant. The paperless factory with barcodes on everything (including the employees). All NEW machines not the refurbished and not supported kind. I will hire managers who listen to the engineers, operators, supervisors and other well meaning folks. I will only build boards with sound DFM/DFT/CE built into them. Wait, what am I thinking� Maybe I�ll just build a Golf course. FORE

Md Cox

reply »

Earl Moon

#10821

Re: Off Pad Printing | 30 June, 1999

| | | | | | | | | | snip | | | | | | | | | | | John and Dave, | | | | | | | | | | | | Again, I don't work with larger chip devices with this issue. The company I now work with developed a strategy, based on considerable research (as others of us did in the past), to do things like placing 0603's on 0402 pad configurations. This means having very small (minimal) side, heel, toe, or any other type, filleting. This provides a mechanism for long term reliability in at least one way. | | | | | | | | | | | | One reliabillity issue resolved is that of minimizing large solder fillets thermally and mechanically exerting excessive force on components - especially end caps. This ensures more "flexibility" (actually better mechanical force "averaging" between the device and the substrate/conductor area) as less stress is experienced during soldering operations and operational activities. | | | | | | | | | | | | This goes back to (actually still being used in MIL applications) leadless ceramic chip carrier (LCCC) device types without constraint in the MLB construction. You may not have exactly the design you need, but something close may work very well for you. This is where "dog boning" can be useful - it can provide extra off pad solder paste printing, when required. This can be done in either of the two print directions. | | | | | | | | | | | | Possible great discovery on your part? | | | | | | | | | | | | Earl Moon | | | | | | | | | | | | | | | | | Earl: I agree that large solder fillets can create reliability problems, but that�s not what we�re talking about here. In John�s case, the solder will wet the whole pad and form a fairly uniform layer of solder. It will wet the end caps. And provided the end caps are touching the pads or are close enough be bridged with solder, it will form a fillet between the pad and the end caps. I don�t agree that the solder will flow to the component side of the pad and exert excessive thermal and mechanical force on components - especially end caps. | | | | | | | | | | I�m more concerned about a frail solder joint that suffers from lack of solder than one that�s over-stressed from too much material. We�re talking about how to form a solder bridge to connect the component to the pad!!!! And at best that it will only form a electrical and weak mechanical link, providing there is good metalization on the pads, equal wetting on both end caps, and the component is placed properly for the distinct pad spacing of that component. | | | | | | | | | | Ya know, at the end of the day, I like Mike�s suggestion. Very nice Mike. | | | | | | | | | | Ta | | | | | | | | | | Dave F | | | | | | | | | Dave, | | | | | | | | You're too kind. I can almost see the light now, but maybe not as well as if you could suggest another two or ten books on the subject for me to read. | | | | | | | | Keep me/us straight, | | | | | | | | Earl Moon | | | | | | | Thanks Dave | | | | | | Me thinks I have spent way too many years in the contract world. Working with non CE/DFM designs, you learn to improvise and do what ever it takes to put those itsy bitsy parts on green boards. | | | | | | MD Cox | | | | | | | | | | | MD, | | | | Yeah, and it's so much more rewarding working harder instead of smarter not forgetting how much fun it is to bitch about poor designs, fabs, solder masks, no time with the family, and STUPID MANAGEMENT (that's us included folks!) while having a very small forum to voice our considerable, learned over all that time you mentioned, knowledge and experience. Any of this ring a bell or are we all punch drunk? I certainly can answer for myself in the affirmative. | | | | Moonman | | | Yeper | | You got that s__t right. But tonight all of that will change, at 9pm MST I will be the next Power Ball winner. That�s right folks, I will be 145 million dollars richer. Then I will build the perfect contract manufacturing plant. The paperless factory with barcodes on everything (including the employees). All NEW machines not the refurbished and not supported kind. I will hire managers who listen to the engineers, operators, supervisors and other well meaning folks. I will only build boards with sound DFM/DFT/CE built into them. | Wait, what am I thinking� Maybe I�ll just build a Golf course. | FORE | | Md Cox | | | MD,

You had me going there, but we'll have to split the winnin's. Two ways ain't bad, but Jesus - build another contract manufacturing suck hole and fall back in it - DFM (with another meaning)/CE my ass - what does it matter? The golf hole idea ain't bad, but I'm buying presents for all the beautiful women I see. Think of those possibilities and the happily shortened life I live in another place.

Moonman

reply »

JohnW

#10822

Re: Off Pad Printing - an update | 30 June, 1999

| | | | | | | | | | | | snip | | | | | | | | | | | | | John and Dave, | | | | | | | | | | | | | | Again, I don't work with larger chip devices with this issue. The company I now work with developed a strategy, based on considerable research (as others of us did in the past), to do things like placing 0603's on 0402 pad configurations. This means having very small (minimal) side, heel, toe, or any other type, filleting. This provides a mechanism for long term reliability in at least one way. | | | | | | | | | | | | | | One reliabillity issue resolved is that of minimizing large solder fillets thermally and mechanically exerting excessive force on components - especially end caps. This ensures more "flexibility" (actually better mechanical force "averaging" between the device and the substrate/conductor area) as less stress is experienced during soldering operations and operational activities. | | | | | | | | | | | | | | This goes back to (actually still being used in MIL applications) leadless ceramic chip carrier (LCCC) device types without constraint in the MLB construction. You may not have exactly the design you need, but something close may work very well for you. This is where "dog boning" can be useful - it can provide extra off pad solder paste printing, when required. This can be done in either of the two print directions. | | | | | | | | | | | | | | Possible great discovery on your part? | | | | | | | | | | | | | | Earl Moon | | | | | | | | | | | | | | | | | | | | Earl: I agree that large solder fillets can create reliability problems, but that�s not what we�re talking about here. In John�s case, the solder will wet the whole pad and form a fairly uniform layer of solder. It will wet the end caps. And provided the end caps are touching the pads or are close enough be bridged with solder, it will form a fillet between the pad and the end caps. I don�t agree that the solder will flow to the component side of the pad and exert excessive thermal and mechanical force on components - especially end caps. | | | | | | | | | | | | I�m more concerned about a frail solder joint that suffers from lack of solder than one that�s over-stressed from too much material. We�re talking about how to form a solder bridge to connect the component to the pad!!!! And at best that it will only form a electrical and weak mechanical link, providing there is good metalization on the pads, equal wetting on both end caps, and the component is placed properly for the distinct pad spacing of that component. | | | | | | | | | | | | Ya know, at the end of the day, I like Mike�s suggestion. Very nice Mike. | | | | | | | | | | | | Ta | | | | | | | | | | | | Dave F | | | | | | | | | | | Dave, | | | | | | | | | | You're too kind. I can almost see the light now, but maybe not as well as if you could suggest another two or ten books on the subject for me to read. | | | | | | | | | | Keep me/us straight, | | | | | | | | | | Earl Moon | | | | | | | | | Thanks Dave | | | | | | | | Me thinks I have spent way too many years in the contract world. Working with non CE/DFM designs, you learn to improvise and do what ever it takes to put those itsy bitsy parts on green boards. | | | | | | | | MD Cox | | | | | | | | | | | | | | | MD, | | | | | | Yeah, and it's so much more rewarding working harder instead of smarter not forgetting how much fun it is to bitch about poor designs, fabs, solder masks, no time with the family, and STUPID MANAGEMENT (that's us included folks!) while having a very small forum to voice our considerable, learned over all that time you mentioned, knowledge and experience. Any of this ring a bell or are we all punch drunk? I certainly can answer for myself in the affirmative. | | | | | | Moonman | | | | | Yeper | | | | You got that s__t right. But tonight all of that will change, at 9pm MST I will be the next Power Ball winner. That�s right folks, I will be 145 million dollars richer. Then I will build the perfect contract manufacturing plant. The paperless factory with barcodes on everything (including the employees). All NEW machines not the refurbished and not supported kind. I will hire managers who listen to the engineers, operators, supervisors and other well meaning folks. I will only build boards with sound DFM/DFT/CE built into them. | | Wait, what am I thinking� Maybe I�ll just build a Golf course. | | FORE | | | | Md Cox | | | | | | | MD, | | You had me going there, but we'll have to split the winnin's. Two ways ain't bad, but Jesus - build another contract manufacturing suck hole and fall back in it - DFM (with another meaning)/CE my ass - what does it matter? The golf hole idea ain't bad, but I'm buying presents for all the beautiful women I see. Think of those possibilities and the happily shortened life I live in another place. | | Moonman | Hey folk's, I thought I'd bring you up to date on the joy ( or is it pain) that is my current meaning of life, yep that board with the 1206's and 1210's. First off a bit thank's to you all for the advice, as alway's it's sound but then what else would you expect ( now can I kiss up or what ?) Anyway's looked into using bigger part's but that's not allowed, liked the idea of the the conductive epoxy and resist but I'm afraid that's a little bit out of the question just now. I've gone for the off pad printing approch and it seem's to be working..I used the home plate design that I saw you all chatting about a while back, unfortuantely the stencil manufacturer decided to put in circles in stead..go figure that one ?, So my next step is to come up with some refined appeture designs to combat the solder balls..getting the home plates actually cut in the stencil will be a start. The only niggle for me is as Dave said wether the joint is going to be mechanically strong enough..time will tell.

As for the follow on debate on the I'd love to work smarter..I remember a whole day when I'm sure I managed smart and not harder..then again.. I've heard of this factory that MD is talking about..I think it's in never never land but unfortunately not recruiting..I'd be the first in line I'll tell you.

I hear it's also got account manager's that know ehrn to tell a customer err, sorry no we wont built that for you!

Punch drunk..all the time, and I never get a chance to recover from yesterday's hangover!!!

anyway, once again a big thank you and I'll let you know when I finally got it cracked.

See ya folk's

JohnW

reply »

Earl Moon

#10823

Re: Off Pad Printing - an update | 30 June, 1999

| | | | | | | | | | | | | | snip | | | | | | | | | | | | | | | John and Dave, | | | | | | | | | | | | | | | | Again, I don't work with larger chip devices with this issue. The company I now work with developed a strategy, based on considerable research (as others of us did in the past), to do things like placing 0603's on 0402 pad configurations. This means having very small (minimal) side, heel, toe, or any other type, filleting. This provides a mechanism for long term reliability in at least one way. | | | | | | | | | | | | | | | | One reliabillity issue resolved is that of minimizing large solder fillets thermally and mechanically exerting excessive force on components - especially end caps. This ensures more "flexibility" (actually better mechanical force "averaging" between the device and the substrate/conductor area) as less stress is experienced during soldering operations and operational activities. | | | | | | | | | | | | | | | | This goes back to (actually still being used in MIL applications) leadless ceramic chip carrier (LCCC) device types without constraint in the MLB construction. You may not have exactly the design you need, but something close may work very well for you. This is where "dog boning" can be useful - it can provide extra off pad solder paste printing, when required. This can be done in either of the two print directions. | | | | | | | | | | | | | | | | Possible great discovery on your part? | | | | | | | | | | | | | | | | Earl Moon | | | | | | | | | | | | | | | | | | | | | | | Earl: I agree that large solder fillets can create reliability problems, but that�s not what we�re talking about here. In John�s case, the solder will wet the whole pad and form a fairly uniform layer of solder. It will wet the end caps. And provided the end caps are touching the pads or are close enough be bridged with solder, it will form a fillet between the pad and the end caps. I don�t agree that the solder will flow to the component side of the pad and exert excessive thermal and mechanical force on components - especially end caps. | | | | | | | | | | | | | | I�m more concerned about a frail solder joint that suffers from lack of solder than one that�s over-stressed from too much material. We�re talking about how to form a solder bridge to connect the component to the pad!!!! And at best that it will only form a electrical and weak mechanical link, providing there is good metalization on the pads, equal wetting on both end caps, and the component is placed properly for the distinct pad spacing of that component. | | | | | | | | | | | | | | Ya know, at the end of the day, I like Mike�s suggestion. Very nice Mike. | | | | | | | | | | | | | | Ta | | | | | | | | | | | | | | Dave F | | | | | | | | | | | | | Dave, | | | | | | | | | | | | You're too kind. I can almost see the light now, but maybe not as well as if you could suggest another two or ten books on the subject for me to read. | | | | | | | | | | | | Keep me/us straight, | | | | | | | | | | | | Earl Moon | | | | | | | | | | | Thanks Dave | | | | | | | | | | Me thinks I have spent way too many years in the contract world. Working with non CE/DFM designs, you learn to improvise and do what ever it takes to put those itsy bitsy parts on green boards. | | | | | | | | | | MD Cox | | | | | | | | | | | | | | | | | | | MD, | | | | | | | | Yeah, and it's so much more rewarding working harder instead of smarter not forgetting how much fun it is to bitch about poor designs, fabs, solder masks, no time with the family, and STUPID MANAGEMENT (that's us included folks!) while having a very small forum to voice our considerable, learned over all that time you mentioned, knowledge and experience. Any of this ring a bell or are we all punch drunk? I certainly can answer for myself in the affirmative. | | | | | | | | Moonman | | | | | | | Yeper | | | | | | You got that s__t right. But tonight all of that will change, at 9pm MST I will be the next Power Ball winner. That�s right folks, I will be 145 million dollars richer. Then I will build the perfect contract manufacturing plant. The paperless factory with barcodes on everything (including the employees). All NEW machines not the refurbished and not supported kind. I will hire managers who listen to the engineers, operators, supervisors and other well meaning folks. I will only build boards with sound DFM/DFT/CE built into them. | | | Wait, what am I thinking� Maybe I�ll just build a Golf course. | | | FORE | | | | | | Md Cox | | | | | | | | | | | MD, | | | | You had me going there, but we'll have to split the winnin's. Two ways ain't bad, but Jesus - build another contract manufacturing suck hole and fall back in it - DFM (with another meaning)/CE my ass - what does it matter? The golf hole idea ain't bad, but I'm buying presents for all the beautiful women I see. Think of those possibilities and the happily shortened life I live in another place. | | | | Moonman | | | Hey folk's, I thought I'd bring you up to date on the joy ( or is it pain) that is my current meaning of life, yep that board with the 1206's and 1210's. | First off a bit thank's to you all for the advice, as alway's it's sound but then what else would you expect ( now can I kiss up or what ?) | Anyway's looked into using bigger part's but that's not allowed, liked the idea of the the conductive epoxy and resist but I'm afraid that's a little bit out of the question just now. | I've gone for the off pad printing approch and it seem's to be working..I used the home plate design that I saw you all chatting about a while back, unfortuantely the stencil manufacturer decided to put in circles in stead..go figure that one ?, | So my next step is to come up with some refined appeture designs to combat the solder balls..getting the home plates actually cut in the stencil will be a start. | The only niggle for me is as Dave said wether the joint is going to be mechanically strong enough..time will tell. | | As for the follow on debate on the I'd love to work smarter..I remember a whole day when I'm sure I managed smart and not harder..then again.. | I've heard of this factory that MD is talking about..I think it's in never never land but unfortunately not recruiting..I'd be the first in line I'll tell you. | | I hear it's also got account manager's that know ehrn to tell a customer err, sorry no we wont built that for you! | | Punch drunk..all the time, and I never get a chance to recover from yesterday's hangover!!! | | anyway, once again a big thank you and I'll let you know when I finally got it cracked. | | See ya folk's | | JohnW | John,

It's not easy. That's why we're paid the "big" bucks. If the customer is not part of the DFM/CE process, it's hopeless. Lot's of work to be done as wages go down and hours go up as well as management appreciation. Ask big Steve G. He, like us all, is trying to find a better place. The better place is here and now - with management understanding.

Boogie,

Earl Moon

reply »

JohnW

#10824

Re: Off Pad Printing - an update...big money ? | 30 June, 1999

| | | | | | | | | | | | | | | | snip | | | | | | | | | | | | | | | | | John and Dave, | | | | | | | | | | | | | | | | | | Again, I don't work with larger chip devices with this issue. The company I now work with developed a strategy, based on considerable research (as others of us did in the past), to do things like placing 0603's on 0402 pad configurations. This means having very small (minimal) side, heel, toe, or any other type, filleting. This provides a mechanism for long term reliability in at least one way. | | | | | | | | | | | | | | | | | | One reliabillity issue resolved is that of minimizing large solder fillets thermally and mechanically exerting excessive force on components - especially end caps. This ensures more "flexibility" (actually better mechanical force "averaging" between the device and the substrate/conductor area) as less stress is experienced during soldering operations and operational activities. | | | | | | | | | | | | | | | | | | This goes back to (actually still being used in MIL applications) leadless ceramic chip carrier (LCCC) device types without constraint in the MLB construction. You may not have exactly the design you need, but something close may work very well for you. This is where "dog boning" can be useful - it can provide extra off pad solder paste printing, when required. This can be done in either of the two print directions. | | | | | | | | | | | | | | | | | | Possible great discovery on your part? | | | | | | | | | | | | | | | | | | Earl Moon | | | | | | | | | | | | | | | | | | | | | | | | | | Earl: I agree that large solder fillets can create reliability problems, but that�s not what we�re talking about here. In John�s case, the solder will wet the whole pad and form a fairly uniform layer of solder. It will wet the end caps. And provided the end caps are touching the pads or are close enough be bridged with solder, it will form a fillet between the pad and the end caps. I don�t agree that the solder will flow to the component side of the pad and exert excessive thermal and mechanical force on components - especially end caps. | | | | | | | | | | | | | | | | I�m more concerned about a frail solder joint that suffers from lack of solder than one that�s over-stressed from too much material. We�re talking about how to form a solder bridge to connect the component to the pad!!!! And at best that it will only form a electrical and weak mechanical link, providing there is good metalization on the pads, equal wetting on both end caps, and the component is placed properly for the distinct pad spacing of that component. | | | | | | | | | | | | | | | | Ya know, at the end of the day, I like Mike�s suggestion. Very nice Mike. | | | | | | | | | | | | | | | | Ta | | | | | | | | | | | | | | | | Dave F | | | | | | | | | | | | | | | Dave, | | | | | | | | | | | | | | You're too kind. I can almost see the light now, but maybe not as well as if you could suggest another two or ten books on the subject for me to read. | | | | | | | | | | | | | | Keep me/us straight, | | | | | | | | | | | | | | Earl Moon | | | | | | | | | | | | | Thanks Dave | | | | | | | | | | | | Me thinks I have spent way too many years in the contract world. Working with non CE/DFM designs, you learn to improvise and do what ever it takes to put those itsy bitsy parts on green boards. | | | | | | | | | | | | MD Cox | | | | | | | | | | | | | | | | | | | | | | | MD, | | | | | | | | | | Yeah, and it's so much more rewarding working harder instead of smarter not forgetting how much fun it is to bitch about poor designs, fabs, solder masks, no time with the family, and STUPID MANAGEMENT (that's us included folks!) while having a very small forum to voice our considerable, learned over all that time you mentioned, knowledge and experience. Any of this ring a bell or are we all punch drunk? I certainly can answer for myself in the affirmative. | | | | | | | | | | Moonman | | | | | | | | | Yeper | | | | | | | | You got that s__t right. But tonight all of that will change, at 9pm MST I will be the next Power Ball winner. That�s right folks, I will be 145 million dollars richer. Then I will build the perfect contract manufacturing plant. The paperless factory with barcodes on everything (including the employees). All NEW machines not the refurbished and not supported kind. I will hire managers who listen to the engineers, operators, supervisors and other well meaning folks. I will only build boards with sound DFM/DFT/CE built into them. | | | | Wait, what am I thinking� Maybe I�ll just build a Golf course. | | | | FORE | | | | | | | | Md Cox | | | | | | | | | | | | | | | MD, | | | | | | You had me going there, but we'll have to split the winnin's. Two ways ain't bad, but Jesus - build another contract manufacturing suck hole and fall back in it - DFM (with another meaning)/CE my ass - what does it matter? The golf hole idea ain't bad, but I'm buying presents for all the beautiful women I see. Think of those possibilities and the happily shortened life I live in another place. | | | | | | Moonman | | | | | Hey folk's, I thought I'd bring you up to date on the joy ( or is it pain) that is my current meaning of life, yep that board with the 1206's and 1210's. | | First off a bit thank's to you all for the advice, as alway's it's sound but then what else would you expect ( now can I kiss up or what ?) | | Anyway's looked into using bigger part's but that's not allowed, liked the idea of the the conductive epoxy and resist but I'm afraid that's a little bit out of the question just now. | | I've gone for the off pad printing approch and it seem's to be working..I used the home plate design that I saw you all chatting about a while back, unfortuantely the stencil manufacturer decided to put in circles in stead..go figure that one ?, | | So my next step is to come up with some refined appeture designs to combat the solder balls..getting the home plates actually cut in the stencil will be a start. | | The only niggle for me is as Dave said wether the joint is going to be mechanically strong enough..time will tell. | | | | As for the follow on debate on the I'd love to work smarter..I remember a whole day when I'm sure I managed smart and not harder..then again.. | | I've heard of this factory that MD is talking about..I think it's in never never land but unfortunately not recruiting..I'd be the first in line I'll tell you. | | | | I hear it's also got account manager's that know ehrn to tell a customer err, sorry no we wont built that for you! | | | | Punch drunk..all the time, and I never get a chance to recover from yesterday's hangover!!! | | | | anyway, once again a big thank you and I'll let you know when I finally got it cracked. | | | | See ya folk's | | | | JohnW | | | John, | | It's not easy. That's why we're paid the "big" bucks. If the customer is not part of the DFM/CE process, it's hopeless. Lot's of work to be done as wages go down and hours go up as well as management appreciation. Ask big Steve G. He, like us all, is trying to find a better place. The better place is here and now - with management understanding. | | Boogie, | | Earl Moon | Earl,

Big money ???? if only that were true, part of the reason I'm looking for the exit. I think the management understanding is key but one of the biggest hurdles is the "don't confuse me with the fact's" approach and the drive for numbers rather than quality, and it's starting to come through in more board design's, sadly not everyone think's about how the heck they are going to build it since that's the CEM's job. Still stop's my life from being dull. On the plus the customer has now agreed to go back to his board design house and push for layout improvements! but that will be a while.. and to think my only worry with these boards was the warp..up to 5mm in some! ( and the boards only 230mm long!)...oh the fun times.

see ya

JohnW

reply »

Earl Moon

#10825

Re: Off Pad Printing - an update...big money ? | 30 June, 1999

| | | | | | | | | | | | | | | | | | snip | | | | | | | | | | | | | | | | | | | John and Dave, | | | | | | | | | | | | | | | | | | | | Again, I don't work with larger chip devices with this issue. The company I now work with developed a strategy, based on considerable research (as others of us did in the past), to do things like placing 0603's on 0402 pad configurations. This means having very small (minimal) side, heel, toe, or any other type, filleting. This provides a mechanism for long term reliability in at least one way. | | | | | | | | | | | | | | | | | | | | One reliabillity issue resolved is that of minimizing large solder fillets thermally and mechanically exerting excessive force on components - especially end caps. This ensures more "flexibility" (actually better mechanical force "averaging" between the device and the substrate/conductor area) as less stress is experienced during soldering operations and operational activities. | | | | | | | | | | | | | | | | | | | | This goes back to (actually still being used in MIL applications) leadless ceramic chip carrier (LCCC) device types without constraint in the MLB construction. You may not have exactly the design you need, but something close may work very well for you. This is where "dog boning" can be useful - it can provide extra off pad solder paste printing, when required. This can be done in either of the two print directions. | | | | | | | | | | | | | | | | | | | | Possible great discovery on your part? | | | | | | | | | | | | | | | | | | | | Earl Moon | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Earl: I agree that large solder fillets can create reliability problems, but that�s not what we�re talking about here. In John�s case, the solder will wet the whole pad and form a fairly uniform layer of solder. It will wet the end caps. And provided the end caps are touching the pads or are close enough be bridged with solder, it will form a fillet between the pad and the end caps. I don�t agree that the solder will flow to the component side of the pad and exert excessive thermal and mechanical force on components - especially end caps. | | | | | | | | | | | | | | | | | | I�m more concerned about a frail solder joint that suffers from lack of solder than one that�s over-stressed from too much material. We�re talking about how to form a solder bridge to connect the component to the pad!!!! And at best that it will only form a electrical and weak mechanical link, providing there is good metalization on the pads, equal wetting on both end caps, and the component is placed properly for the distinct pad spacing of that component. | | | | | | | | | | | | | | | | | | Ya know, at the end of the day, I like Mike�s suggestion. Very nice Mike. | | | | | | | | | | | | | | | | | | Ta | | | | | | | | | | | | | | | | | | Dave F | | | | | | | | | | | | | | | | | Dave, | | | | | | | | | | | | | | | | You're too kind. I can almost see the light now, but maybe not as well as if you could suggest another two or ten books on the subject for me to read. | | | | | | | | | | | | | | | | Keep me/us straight, | | | | | | | | | | | | | | | | Earl Moon | | | | | | | | | | | | | | | Thanks Dave | | | | | | | | | | | | | | Me thinks I have spent way too many years in the contract world. Working with non CE/DFM designs, you learn to improvise and do what ever it takes to put those itsy bitsy parts on green boards. | | | | | | | | | | | | | | MD Cox | | | | | | | | | | | | | | | | | | | | | | | | | | | MD, | | | | | | | | | | | | Yeah, and it's so much more rewarding working harder instead of smarter not forgetting how much fun it is to bitch about poor designs, fabs, solder masks, no time with the family, and STUPID MANAGEMENT (that's us included folks!) while having a very small forum to voice our considerable, learned over all that time you mentioned, knowledge and experience. Any of this ring a bell or are we all punch drunk? I certainly can answer for myself in the affirmative. | | | | | | | | | | | | Moonman | | | | | | | | | | | Yeper | | | | | | | | | | You got that s__t right. But tonight all of that will change, at 9pm MST I will be the next Power Ball winner. That�s right folks, I will be 145 million dollars richer. Then I will build the perfect contract manufacturing plant. The paperless factory with barcodes on everything (including the employees). All NEW machines not the refurbished and not supported kind. I will hire managers who listen to the engineers, operators, supervisors and other well meaning folks. I will only build boards with sound DFM/DFT/CE built into them. | | | | | Wait, what am I thinking� Maybe I�ll just build a Golf course. | | | | | FORE | | | | | | | | | | Md Cox | | | | | | | | | | | | | | | | | | | MD, | | | | | | | | You had me going there, but we'll have to split the winnin's. Two ways ain't bad, but Jesus - build another contract manufacturing suck hole and fall back in it - DFM (with another meaning)/CE my ass - what does it matter? The golf hole idea ain't bad, but I'm buying presents for all the beautiful women I see. Think of those possibilities and the happily shortened life I live in another place. | | | | | | | | Moonman | | | | | | | Hey folk's, I thought I'd bring you up to date on the joy ( or is it pain) that is my current meaning of life, yep that board with the 1206's and 1210's. | | | First off a bit thank's to you all for the advice, as alway's it's sound but then what else would you expect ( now can I kiss up or what ?) | | | Anyway's looked into using bigger part's but that's not allowed, liked the idea of the the conductive epoxy and resist but I'm afraid that's a little bit out of the question just now. | | | I've gone for the off pad printing approch and it seem's to be working..I used the home plate design that I saw you all chatting about a while back, unfortuantely the stencil manufacturer decided to put in circles in stead..go figure that one ?, | | | So my next step is to come up with some refined appeture designs to combat the solder balls..getting the home plates actually cut in the stencil will be a start. | | | The only niggle for me is as Dave said wether the joint is going to be mechanically strong enough..time will tell. | | | | | | As for the follow on debate on the I'd love to work smarter..I remember a whole day when I'm sure I managed smart and not harder..then again.. | | | I've heard of this factory that MD is talking about..I think it's in never never land but unfortunately not recruiting..I'd be the first in line I'll tell you. | | | | | | I hear it's also got account manager's that know ehrn to tell a customer err, sorry no we wont built that for you! | | | | | | Punch drunk..all the time, and I never get a chance to recover from yesterday's hangover!!! | | | | | | anyway, once again a big thank you and I'll let you know when I finally got it cracked. | | | | | | See ya folk's | | | | | | JohnW | | | | | John, | | | | It's not easy. That's why we're paid the "big" bucks. If the customer is not part of the DFM/CE process, it's hopeless. Lot's of work to be done as wages go down and hours go up as well as management appreciation. Ask big Steve G. He, like us all, is trying to find a better place. The better place is here and now - with management understanding. | | | | Boogie, | | | | Earl Moon | | | Earl, | | Big money ???? if only that were true, part of the reason I'm looking for the exit. | I think the management understanding is key but one of the biggest hurdles is the "don't confuse me with the fact's" approach and the drive for numbers rather than quality, and it's starting to come through in more board design's, sadly not everyone think's about how the heck they are going to build it since that's the CEM's job. | Still stop's my life from being dull. | On the plus the customer has now agreed to go back to his board design house and push for layout improvements! but that will be a while.. | and to think my only worry with these boards was the warp..up to 5mm in some! ( and the boards only 230mm long!)...oh the fun times. | | see ya | | JohnW | Big Bad John,

You summarized it all well. Many are looking for the exit. Live being dull is relative as I once had a girlfriend who was an ex-bullfighter turned English prof. Only thing is, as Big Bad Steve is finding (just as do you and I - in over half the contracts I enter into), it's pretty much the same out there.

I agree, bean counter mentality prevails - as it always has and always will but now for the wrong reaons. It it is prevalent now because of the need for instant gratification. The excuse is to satisfy customer need as quickly as possible no matter how much it hurts the bottom line. Placements and cash flow, that's the ticket.

If management, in its infinite wisdom, took a "real course in economics" it would find both financial reward and gratification would come more easily if all of us were permitted to do it right the first time. All of us includes the customer, management, us, and all other supplier representatives.

I know the term DFM/CE seems overused (just wait for so much more), but it holds many of the answers you already understand. If designs, materials, components, boards, etc. were as they should be, we'd all better manage our processes.

And on it goes --- just ask Steve and where is he now? Just as you and me, he is looking for, or has found, a place that hopefully has learned more than the last place so our contributions will be appreciated both monetarily and emotionally. Money and an ass pat works for me - save the pat part.

And on it goes again,

Earl Moon

reply »

JohnW

#10826

Re: Off Pad Printing - an update...big money ? | 1 July, 1999

| | | | | | | | | | | | | | | | | | | | snip | | | | | | | | | | | | | | | | | | | | | John and Dave, | | | | | | | | | | | | | | | | | | | | | | Again, I don't work with larger chip devices with this issue. The company I now work with developed a strategy, based on considerable research (as others of us did in the past), to do things like placing 0603's on 0402 pad configurations. This means having very small (minimal) side, heel, toe, or any other type, filleting. This provides a mechanism for long term reliability in at least one way. | | | | | | | | | | | | | | | | | | | | | | One reliabillity issue resolved is that of minimizing large solder fillets thermally and mechanically exerting excessive force on components - especially end caps. This ensures more "flexibility" (actually better mechanical force "averaging" between the device and the substrate/conductor area) as less stress is experienced during soldering operations and operational activities. | | | | | | | | | | | | | | | | | | | | | | This goes back to (actually still being used in MIL applications) leadless ceramic chip carrier (LCCC) device types without constraint in the MLB construction. You may not have exactly the design you need, but something close may work very well for you. This is where "dog boning" can be useful - it can provide extra off pad solder paste printing, when required. This can be done in either of the two print directions. | | | | | | | | | | | | | | | | | | | | | | Possible great discovery on your part? | | | | | | | | | | | | | | | | | | | | | | Earl Moon | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Earl: I agree that large solder fillets can create reliability problems, but that�s not what we�re talking about here. In John�s case, the solder will wet the whole pad and form a fairly uniform layer of solder. It will wet the end caps. And provided the end caps are touching the pads or are close enough be bridged with solder, it will form a fillet between the pad and the end caps. I don�t agree that the solder will flow to the component side of the pad and exert excessive thermal and mechanical force on components - especially end caps. | | | | | | | | | | | | | | | | | | | | I�m more concerned about a frail solder joint that suffers from lack of solder than one that�s over-stressed from too much material. We�re talking about how to form a solder bridge to connect the component to the pad!!!! And at best that it will only form a electrical and weak mechanical link, providing there is good metalization on the pads, equal wetting on both end caps, and the component is placed properly for the distinct pad spacing of that component. | | | | | | | | | | | | | | | | | | | | Ya know, at the end of the day, I like Mike�s suggestion. Very nice Mike. | | | | | | | | | | | | | | | | | | | | Ta | | | | | | | | | | | | | | | | | | | | Dave F | | | | | | | | | | | | | | | | | | | Dave, | | | | | | | | | | | | | | | | | | You're too kind. I can almost see the light now, but maybe not as well as if you could suggest another two or ten books on the subject for me to read. | | | | | | | | | | | | | | | | | | Keep me/us straight, | | | | | | | | | | | | | | | | | | Earl Moon | | | | | | | | | | | | | | | | | Thanks Dave | | | | | | | | | | | | | | | | Me thinks I have spent way too many years in the contract world. Working with non CE/DFM designs, you learn to improvise and do what ever it takes to put those itsy bitsy parts on green boards. | | | | | | | | | | | | | | | | MD Cox | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | MD, | | | | | | | | | | | | | | Yeah, and it's so much more rewarding working harder instead of smarter not forgetting how much fun it is to bitch about poor designs, fabs, solder masks, no time with the family, and STUPID MANAGEMENT (that's us included folks!) while having a very small forum to voice our considerable, learned over all that time you mentioned, knowledge and experience. Any of this ring a bell or are we all punch drunk? I certainly can answer for myself in the affirmative. | | | | | | | | | | | | | | Moonman | | | | | | | | | | | | | Yeper | | | | | | | | | | | | You got that s__t right. But tonight all of that will change, at 9pm MST I will be the next Power Ball winner. That�s right folks, I will be 145 million dollars richer. Then I will build the perfect contract manufacturing plant. The paperless factory with barcodes on everything (including the employees). All NEW machines not the refurbished and not supported kind. I will hire managers who listen to the engineers, operators, supervisors and other well meaning folks. I will only build boards with sound DFM/DFT/CE built into them. | | | | | | Wait, what am I thinking� Maybe I�ll just build a Golf course. | | | | | | FORE | | | | | | | | | | | | Md Cox | | | | | | | | | | | | | | | | | | | | | | | MD, | | | | | | | | | | You had me going there, but we'll have to split the winnin's. Two ways ain't bad, but Jesus - build another contract manufacturing suck hole and fall back in it - DFM (with another meaning)/CE my ass - what does it matter? The golf hole idea ain't bad, but I'm buying presents for all the beautiful women I see. Think of those possibilities and the happily shortened life I live in another place. | | | | | | | | | | Moonman | | | | | | | | | Hey folk's, I thought I'd bring you up to date on the joy ( or is it pain) that is my current meaning of life, yep that board with the 1206's and 1210's. | | | | First off a bit thank's to you all for the advice, as alway's it's sound but then what else would you expect ( now can I kiss up or what ?) | | | | Anyway's looked into using bigger part's but that's not allowed, liked the idea of the the conductive epoxy and resist but I'm afraid that's a little bit out of the question just now. | | | | I've gone for the off pad printing approch and it seem's to be working..I used the home plate design that I saw you all chatting about a while back, unfortuantely the stencil manufacturer decided to put in circles in stead..go figure that one ?, | | | | So my next step is to come up with some refined appeture designs to combat the solder balls..getting the home plates actually cut in the stencil will be a start. | | | | The only niggle for me is as Dave said wether the joint is going to be mechanically strong enough..time will tell. | | | | | | | | As for the follow on debate on the I'd love to work smarter..I remember a whole day when I'm sure I managed smart and not harder..then again.. | | | | I've heard of this factory that MD is talking about..I think it's in never never land but unfortunately not recruiting..I'd be the first in line I'll tell you. | | | | | | | | I hear it's also got account manager's that know ehrn to tell a customer err, sorry no we wont built that for you! | | | | | | | | Punch drunk..all the time, and I never get a chance to recover from yesterday's hangover!!! | | | | | | | | anyway, once again a big thank you and I'll let you know when I finally got it cracked. | | | | | | | | See ya folk's | | | | | | | | JohnW | | | | | | | John, | | | | | | It's not easy. That's why we're paid the "big" bucks. If the customer is not part of the DFM/CE process, it's hopeless. Lot's of work to be done as wages go down and hours go up as well as management appreciation. Ask big Steve G. He, like us all, is trying to find a better place. The better place is here and now - with management understanding. | | | | | | Boogie, | | | | | | Earl Moon | | | | | Earl, | | | | Big money ???? if only that were true, part of the reason I'm looking for the exit. | | I think the management understanding is key but one of the biggest hurdles is the "don't confuse me with the fact's" approach and the drive for numbers rather than quality, and it's starting to come through in more board design's, sadly not everyone think's about how the heck they are going to build it since that's the CEM's job. | | Still stop's my life from being dull. | | On the plus the customer has now agreed to go back to his board design house and push for layout improvements! but that will be a while.. | | and to think my only worry with these boards was the warp..up to 5mm in some! ( and the boards only 230mm long!)...oh the fun times. | | | | see ya | | | | JohnW | | | Big Bad John, | | You summarized it all well. Many are looking for the exit. Live being dull is relative as I once had a girlfriend who was an ex-bullfighter turned English prof. Only thing is, as Big Bad Steve is finding (just as do you and I - in over half the contracts I enter into), it's pretty much the same out there. | | I agree, bean counter mentality prevails - as it always has and always will but now for the wrong reaons. It it is prevalent now because of the need for instant gratification. The excuse is to satisfy customer need as quickly as possible no matter how much it hurts the bottom line. Placements and cash flow, that's the ticket. | | If management, in its infinite wisdom, took a "real course in economics" it would find both financial reward and gratification would come more easily if all of us were permitted to do it right the first time. All of us includes the customer, management, us, and all other supplier representatives. | | I know the term DFM/CE seems overused (just wait for so much more), but it holds many of the answers you already understand. If designs, materials, components, boards, etc. were as they should be, we'd all better manage our processes. | | And on it goes --- just ask Steve and where is he now? Just as you and me, he is looking for, or has found, a place that hopefully has learned more than the last place so our contributions will be appreciated both monetarily and emotionally. Money and an ass pat works for me - save the pat part. | | And on it goes again, | | Earl Moon | Earl,

I bow to your word's of wisdom, The way I see it one of the only way's of getting the bean counter's to stopand behave nice it to either steal the beans or make em read this forum!

Cheers

JohnW

reply »

Earl Moon

#10827

Re: Off Pad Printing - an update...big money ? | 1 July, 1999

| | | | | | | | | | | | | | | | | | | | | | snip | | | | | | | | | | | | | | | | | | | | | | | John and Dave, | | | | | | | | | | | | | | | | | | | | | | | | Again, I don't work with larger chip devices with this issue. The company I now work with developed a strategy, based on considerable research (as others of us did in the past), to do things like placing 0603's on 0402 pad configurations. This means having very small (minimal) side, heel, toe, or any other type, filleting. This provides a mechanism for long term reliability in at least one way. | | | | | | | | | | | | | | | | | | | | | | | | One reliabillity issue resolved is that of minimizing large solder fillets thermally and mechanically exerting excessive force on components - especially end caps. This ensures more "flexibility" (actually better mechanical force "averaging" between the device and the substrate/conductor area) as less stress is experienced during soldering operations and operational activities. | | | | | | | | | | | | | | | | | | | | | | | | This goes back to (actually still being used in MIL applications) leadless ceramic chip carrier (LCCC) device types without constraint in the MLB construction. You may not have exactly the design you need, but something close may work very well for you. This is where "dog boning" can be useful - it can provide extra off pad solder paste printing, when required. This can be done in either of the two print directions. | | | | | | | | | | | | | | | | | | | | | | | | Possible great discovery on your part? | | | | | | | | | | | | | | | | | | | | | | | | Earl Moon | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Earl: I agree that large solder fillets can create reliability problems, but that�s not what we�re talking about here. In John�s case, the solder will wet the whole pad and form a fairly uniform layer of solder. It will wet the end caps. And provided the end caps are touching the pads or are close enough be bridged with solder, it will form a fillet between the pad and the end caps. I don�t agree that the solder will flow to the component side of the pad and exert excessive thermal and mechanical force on components - especially end caps. | | | | | | | | | | | | | | | | | | | | | | I�m more concerned about a frail solder joint that suffers from lack of solder than one that�s over-stressed from too much material. We�re talking about how to form a solder bridge to connect the component to the pad!!!! And at best that it will only form a electrical and weak mechanical link, providing there is good metalization on the pads, equal wetting on both end caps, and the component is placed properly for the distinct pad spacing of that component. | | | | | | | | | | | | | | | | | | | | | | Ya know, at the end of the day, I like Mike�s suggestion. Very nice Mike. | | | | | | | | | | | | | | | | | | | | | | Ta | | | | | | | | | | | | | | | | | | | | | | Dave F | | | | | | | | | | | | | | | | | | | | | Dave, | | | | | | | | | | | | | | | | | | | | You're too kind. I can almost see the light now, but maybe not as well as if you could suggest another two or ten books on the subject for me to read. | | | | | | | | | | | | | | | | | | | | Keep me/us straight, | | | | | | | | | | | | | | | | | | | | Earl Moon | | | | | | | | | | | | | | | | | | | Thanks Dave | | | | | | | | | | | | | | | | | | Me thinks I have spent way too many years in the contract world. Working with non CE/DFM designs, you learn to improvise and do what ever it takes to put those itsy bitsy parts on green boards. | | | | | | | | | | | | | | | | | | MD Cox | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | MD, | | | | | | | | | | | | | | | | Yeah, and it's so much more rewarding working harder instead of smarter not forgetting how much fun it is to bitch about poor designs, fabs, solder masks, no time with the family, and STUPID MANAGEMENT (that's us included folks!) while having a very small forum to voice our considerable, learned over all that time you mentioned, knowledge and experience. Any of this ring a bell or are we all punch drunk? I certainly can answer for myself in the affirmative. | | | | | | | | | | | | | | | | Moonman | | | | | | | | | | | | | | | Yeper | | | | | | | | | | | | | | You got that s__t right. But tonight all of that will change, at 9pm MST I will be the next Power Ball winner. That�s right folks, I will be 145 million dollars richer. Then I will build the perfect contract manufacturing plant. The paperless factory with barcodes on everything (including the employees). All NEW machines not the refurbished and not supported kind. I will hire managers who listen to the engineers, operators, supervisors and other well meaning folks. I will only build boards with sound DFM/DFT/CE built into them. | | | | | | | Wait, what am I thinking� Maybe I�ll just build a Golf course. | | | | | | | FORE | | | | | | | | | | | | | | Md Cox | | | | | | | | | | | | | | | | | | | | | | | | | | | MD, | | | | | | | | | | | | You had me going there, but we'll have to split the winnin's. Two ways ain't bad, but Jesus - build another contract manufacturing suck hole and fall back in it - DFM (with another meaning)/CE my ass - what does it matter? The golf hole idea ain't bad, but I'm buying presents for all the beautiful women I see. Think of those possibilities and the happily shortened life I live in another place. | | | | | | | | | | | | Moonman | | | | | | | | | | | Hey folk's, I thought I'd bring you up to date on the joy ( or is it pain) that is my current meaning of life, yep that board with the 1206's and 1210's. | | | | | First off a bit thank's to you all for the advice, as alway's it's sound but then what else would you expect ( now can I kiss up or what ?) | | | | | Anyway's looked into using bigger part's but that's not allowed, liked the idea of the the conductive epoxy and resist but I'm afraid that's a little bit out of the question just now. | | | | | I've gone for the off pad printing approch and it seem's to be working..I used the home plate design that I saw you all chatting about a while back, unfortuantely the stencil manufacturer decided to put in circles in stead..go figure that one ?, | | | | | So my next step is to come up with some refined appeture designs to combat the solder balls..getting the home plates actually cut in the stencil will be a start. | | | | | The only niggle for me is as Dave said wether the joint is going to be mechanically strong enough..time will tell. | | | | | | | | | | As for the follow on debate on the I'd love to work smarter..I remember a whole day when I'm sure I managed smart and not harder..then again.. | | | | | I've heard of this factory that MD is talking about..I think it's in never never land but unfortunately not recruiting..I'd be the first in line I'll tell you. | | | | | | | | | | I hear it's also got account manager's that know ehrn to tell a customer err, sorry no we wont built that for you! | | | | | | | | | | Punch drunk..all the time, and I never get a chance to recover from yesterday's hangover!!! | | | | | | | | | | anyway, once again a big thank you and I'll let you know when I finally got it cracked. | | | | | | | | | | See ya folk's | | | | | | | | | | JohnW | | | | | | | | | John, | | | | | | | | It's not easy. That's why we're paid the "big" bucks. If the customer is not part of the DFM/CE process, it's hopeless. Lot's of work to be done as wages go down and hours go up as well as management appreciation. Ask big Steve G. He, like us all, is trying to find a better place. The better place is here and now - with management understanding. | | | | | | | | Boogie, | | | | | | | | Earl Moon | | | | | | | Earl, | | | | | | Big money ???? if only that were true, part of the reason I'm looking for the exit. | | | I think the management understanding is key but one of the biggest hurdles is the "don't confuse me with the fact's" approach and the drive for numbers rather than quality, and it's starting to come through in more board design's, sadly not everyone think's about how the heck they are going to build it since that's the CEM's job. | | | Still stop's my life from being dull. | | | On the plus the customer has now agreed to go back to his board design house and push for layout improvements! but that will be a while.. | | | and to think my only worry with these boards was the warp..up to 5mm in some! ( and the boards only 230mm long!)...oh the fun times. | | | | | | see ya | | | | | | JohnW | | | | | Big Bad John, | | | | You summarized it all well. Many are looking for the exit. Live being dull is relative as I once had a girlfriend who was an ex-bullfighter turned English prof. Only thing is, as Big Bad Steve is finding (just as do you and I - in over half the contracts I enter into), it's pretty much the same out there. | | | | I agree, bean counter mentality prevails - as it always has and always will but now for the wrong reaons. It it is prevalent now because of the need for instant gratification. The excuse is to satisfy customer need as quickly as possible no matter how much it hurts the bottom line. Placements and cash flow, that's the ticket. | | | | If management, in its infinite wisdom, took a "real course in economics" it would find both financial reward and gratification would come more easily if all of us were permitted to do it right the first time. All of us includes the customer, management, us, and all other supplier representatives. | | | | I know the term DFM/CE seems overused (just wait for so much more), but it holds many of the answers you already understand. If designs, materials, components, boards, etc. were as they should be, we'd all better manage our processes. | | | | And on it goes --- just ask Steve and where is he now? Just as you and me, he is looking for, or has found, a place that hopefully has learned more than the last place so our contributions will be appreciated both monetarily and emotionally. Money and an ass pat works for me - save the pat part. | | | | And on it goes again, | | | | Earl Moon | | | Earl, | | I bow to your word's of wisdom, The way I see it one of the only way's of getting the bean counter's to stopand behave nice it to either steal the beans or make em read this forum! | | Cheers | | JohnW | John

You needn't bow to anything or anyone. You have it all. What you don't, the rest of this forum does. Plus, you are right about management. Maybe Cunli should develop a management corner to get these folks on board. One way or another, they must learn and respect what you all know so changes will be made (positive change is known as improvement).

Earl

reply »

reflow oven profiler

Lead Free Wave Solder - 1 Click SMT