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all powerfull UP78..or is it..?

JohnW

#11627

all powerfull UP78..or is it..? | 29 April, 1999

Ok folk's has anyone used Alpha Metal's UP78 solder paste ?

Our place is looking to move to that as the way to go, getting rid of the Hereaus 362's and Alpha 737's of the current set up.

My question's are really : how is the printability of the paste do I need to further reduce appeture sizes from what I would normally run on say 737 ~ 2 thou reductions solderballs..seen any..? I know alpha are claiming it to be a modern miricle but as yet their technical team cant give me many guildlines on it and the one time it has run in our place it ran badly which is not to say that the paste was to blame but.. so I thought I would ask the 'informed'since I know the power's that be are gonna push it thru without asking anyway's..I thought it would be nice to at least cost new screen's for all the products we run with new appeture reductions if there gonna be needed...ha what fun it must be to make these decisions from upon hi..or am I just being cynical ?

John

reply »

#11628

Re: all powerfull UP78..or is it..? | 30 April, 1999

| Ok folk's has anyone used Alpha Metal's UP78 solder paste ? | | Our place is looking to move to that as the way to go, getting rid of the Hereaus 362's and Alpha 737's of the current set up. | | My question's are really : | how is the printability of the paste | do I need to further reduce appeture sizes from what I would normally run on say 737 ~ 2 thou reductions | solderballs..seen any..?

| I know alpha are claiming it to be a modern miricle but as yet their technical team cant give me many guildlines on it and the one time it has run in our place it ran badly which is not to say that the paste was to blame but.. | so I thought I would ask the 'informed'since I know the power's that be are gonna push it thru without asking anyway's..I thought it would be nice to at least cost new screen's for all the products we run with new appeture reductions if there gonna be needed...ha what fun it must be to make these decisions from upon hi..or am I just being cynical ? | | John |

John,

The printability of this paste is like nothing I've ever seen before. To risk sounding like Marcia Brady, it's absolutely the dreamiest paste I've ever worked with. If you make a wish list of all the characteristics you want in a paste - stencil life, good first prints after long pauses, full release, clear, thin residues, etc, etc, it's all here in one package. And it just looks good when you eyeball it on the board. Under magnified photographs, the paste bricks look amazing.

To give you an idea of it's performance relative to it's compettition, we ran paste qualifications here over the winter. The field was narrowed down to three pastes which run on the line for a full week each.

We beat them up, especially the UP78 to se if it stood up to its lofty claims. Let it sit for an hour and a half or two hours on the stencil, in an open environment, and printed it without any kneading. Beautiful print. Turned ALL wipe cycles off the UP3000 - beautiful prints. Recycled pastes from one stencil to another all day long - beautiful prints. And it dropped in - we didn't change a single print parameter to accomodate it.

The next week we put a competitor on the line. By Thursday, I had a technician in my office telling me he'd done everything he possibly could with this paste and he was sick of it. He wanted to go back to the UP78. I okayed it, walked out of my cubicle, and found he alreay had it warmed up and was ready to go.

So I believe.

Now there is no such thing as a free lunch. You want the benefits full release paste, you gotta deal with the ramifications, too. The full release means that ALL the paste is out of the stencil and on the board. You got more volume of paste on your board now than you did with your last formulation.

So do you need to redesign your apertures? Maybe, maybe not. It depends on what you're using for reductions now. If you've got 2 thou reductions on your fine pitch, I'd say you're fine. You probably need home plates or some other type of reduction on your chip components. We are seeing mid-chip solder beads, because we were printing them 1:1.

I've got two new stencils in house that are made with the Alpha guidelines to eliminate the mid-chip solder beads. And I am like a kid at Christmas. I keep bugging the planners to schedule these boards to run, so I can run my experiment and quantify the relationship between the apertures and the beads. The wait is absolutely killing me. When I finally get my info, I'll post it back to this thread.

If you are having difficulty getting guidelines for aperture sizes, call Rob Herber at Alpha - (201) 324-3623.

Chrys

reply »

Wade Oberle

#11629

Re: all powerfull UP78..or is it..? | 30 April, 1999

| | Ok folk's has anyone used Alpha Metal's UP78 solder paste ? | | | | Our place is looking to move to that as the way to go, getting rid of the Hereaus 362's and Alpha 737's of the current set up. | | | | My question's are really : | | how is the printability of the paste | | do I need to further reduce appeture sizes from what I would normally run on say 737 ~ 2 thou reductions | | solderballs..seen any..? | | | | I know alpha are claiming it to be a modern miricle but as yet their technical team cant give me many guildlines on it and the one time it has run in our place it ran badly which is not to say that the paste was to blame but.. | | so I thought I would ask the 'informed'since I know the power's that be are gonna push it thru without asking anyway's..I thought it would be nice to at least cost new screen's for all the products we run with new appeture reductions if there gonna be needed...ha what fun it must be to make these decisions from upon hi..or am I just being cynical ? | | | | John | | | | John, | | The printability of this paste is like nothing I've ever seen before. To risk sounding like Marcia Brady, it's absolutely the dreamiest paste I've ever worked with. If you make a wish list of all the characteristics you want in a paste - stencil life, good first prints after long pauses, full release, clear, thin residues, etc, etc, it's all here in one package. And it just looks good when you eyeball it on the board. Under magnified photographs, the paste bricks look amazing. | | To give you an idea of it's performance relative to it's compettition, we ran paste qualifications here over the winter. The field was narrowed down to three pastes which run on the line for a full week each. | | We beat them up, especially the UP78 to se if it stood up to its lofty claims. Let it sit for an hour and a half or two hours on the stencil, in an open environment, and printed it without any kneading. Beautiful print. Turned ALL wipe cycles off the UP3000 - beautiful prints. Recycled pastes from one stencil to another all day long - beautiful prints. And it dropped in - we didn't change a single print parameter to accomodate it. | | The next week we put a competitor on the line. By Thursday, I had a technician in my office telling me he'd done everything he possibly could with this paste and he was sick of it. He wanted to go back to the UP78. I okayed it, walked out of my cubicle, and found he alreay had it warmed up and was ready to go. | | So I believe. | | Now there is no such thing as a free lunch. You want the benefits full release paste, you gotta deal with the ramifications, too. The full release means that ALL the paste is out of the stencil and on the board. You got more volume of paste on your board now than you did with your last formulation. | | So do you need to redesign your apertures? Maybe, maybe not. It depends on what you're using for reductions now. If you've got 2 thou reductions on your fine pitch, I'd say you're fine. You probably need home plates or some other type of reduction on your chip components. We are seeing mid-chip solder beads, because we were printing them 1:1. | | I've got two new stencils in house that are made with the Alpha guidelines to eliminate the mid-chip solder beads. And I am like a kid at Christmas. I keep bugging the planners to schedule these boards to run, so I can run my experiment and quantify the relationship between the apertures and the beads. The wait is absolutely killing me. When I finally get my info, I'll post it back to this thread. | | If you are having difficulty getting guidelines for aperture sizes, call Rob Herber at Alpha - (201) 324-3623. | | Chrys | I would tend to agree with what Chrys said. I qualified the up 78-osp and found it to be an excellant product but not our first choice. It had an insufficient tack strength and we were skewing chips when the table in the Fuji CP-6 was flying around. We use the home-plate pattern and our designs are from our customers. Sometimes they have the spacing between pads too great and this leaves just the tip of the home-plate pattern to provide all the tack strength to keep the part from moving around. The UP-78osp couldn't do the job. We found an AIM product that could and the price was good. I'm sure Alpha would have matched AIM's price but there was no need.

Wade | | | |

reply »

Kevin Hussey

#11630

Re: all powerfull UP78..or is it..? | 30 April, 1999

| Ok folk's has anyone used Alpha Metal's UP78 solder paste ? | | Our place is looking to move to that as the way to go, getting rid of the Hereaus 362's and Alpha 737's of the current set up. | | My question's are really : | how is the printability of the paste | do I need to further reduce appeture sizes from what I would normally run on say 737 ~ 2 thou reductions | solderballs..seen any..? | I know alpha are claiming it to be a modern miricle but as yet their technical team cant give me many guildlines on it and the one time it has run in our place it ran badly which is not to say that the paste was to blame but.. | so I thought I would ask the 'informed'since I know the power's that be are gonna push it thru without asking anyway's..I thought it would be nice to at least cost new screen's for all the products we run with new appeture reductions if there gonna be needed...ha what fun it must be to make these decisions from upon hi..or am I just being cynical ? | | John |

Hi John!

Your not being cynical, just brutally honest (a quality all upper management fears)! Anyway, UP78.... HATED IT! We've been running a design of experiments (that's DOE for you magazine readers) and the UP78 failed our "Dead Print" experiments and also the "Pin Probability" tests. We printed 25 panels and then let the UP78 sit on the stencil for 45 minutes (to simulate a lunch) and it consistently clogged up the micro BGA openings on our test stencil. It also failed the Pin Probability test on the Pin In Paste portion of our test board. Now all this might not seem too bad, but when I ran this stuff in production, it solder balled to no end! I even had solder balls on SOT23's!!!! That's a first for me! Also had solder fines on all the fine pitch devices.

Alpha then gave us the UP78 PT1 formula. It pasted all our tests but again it solder balled as bad as the regular UP78. Alpha told us that we needed to reduce our stencil opening 10 to 20 percent. So, we had three different stencils made for the same production board. The 1st was a straight 10% reduction on all but the actives. The 2nd was a straight 20% reduction and the third was a 10% reduction using the home plate design on 1206 R's and C's. We ran 4 different pastes on all three stencils. The result was that Alpha did solder ball on ALL three stencils. The size and amount reduced respectively, but still. Now they are telling us we need the "Straight Ramp" oven profile to make this stuff work, as well as increase our squeegee speed from 1"/min to 2"/min!?!?!?!?

I plan to try what they recommend (call me nutty), but I haven't had any problems with the other pastes I tested. I've talked to our Finland plant and they also had the same problems with the balling using Alpha, so at least I know I'm not the only one.

Hope I helped and good luck to you!

KH Factor

reply »

#11631

Re: all powerfull UP78..or is it..? | 2 May, 1999

| | Ok folk's has anyone used Alpha Metal's UP78 solder paste ? | | | | Our place is looking to move to that as the way to go, getting rid of the Hereaus 362's and Alpha 737's of the current set up. | | | | My question's are really : | | how is the printability of the paste | | do I need to further reduce appeture sizes from what I would normally run on say 737 ~ 2 thou reductions | | solderballs..seen any..? | | I know alpha are claiming it to be a modern miricle but as yet their technical team cant give me many guildlines on it and the one time it has run in our place it ran badly which is not to say that the paste was to blame but.. | | so I thought I would ask the 'informed'since I know the power's that be are gonna push it thru without asking anyway's..I thought it would be nice to at least cost new screen's for all the products we run with new appeture reductions if there gonna be needed...ha what fun it must be to make these decisions from upon hi..or am I just being cynical ? | | | | John | | | | Hi John! | | Your not being cynical, just brutally honest (a quality all upper management fears)! Anyway, UP78.... HATED IT! We've been running a design of experiments (that's DOE for you magazine readers) and the UP78 failed our "Dead Print" experiments and also the "Pin Probability" tests. We printed 25 panels and then let the UP78 sit on the stencil for 45 minutes (to simulate a lunch) and it consistently clogged up the micro BGA openings on our test stencil. It also failed the Pin Probability test on the Pin In Paste portion of our test board. Now all this might not seem too bad, but when I ran this stuff in production, it solder balled to no end! I even had solder balls on SOT23's!!!! That's a first for me! Also had solder fines on all the fine pitch devices. | | Alpha then gave us the UP78 PT1 formula. It pasted all our tests but again it solder balled as bad as the regular UP78. Alpha told us that we needed to reduce our stencil opening 10 to 20 percent. So, we had three different stencils made for the same production board. The 1st was a straight 10% reduction on all but the actives. The 2nd was a straight 20% reduction and the third was a 10% reduction using the home plate design on 1206 R's and C's. We ran 4 different pastes on all three stencils. The result was that Alpha did solder ball on ALL three stencils. The size and amount reduced respectively, but still. Now they are telling us we need the "Straight Ramp" oven profile to make this stuff work, as well as increase our squeegee speed from 1"/min to 2"/min!?!?!?!? | | I plan to try what they recommend (call me nutty), but I haven't had any problems with the other pastes I tested. I've talked to our Finland plant and they also had the same problems with the balling using Alpha, so at least I know I'm not the only one. | | Hope I helped and good luck to you! | | KH Factor | | Whoa, Kevin. Major bad experience, dude. I feel for ya.

I'm a much cheaper date than you. Finest pitch is 18 mil (only one device though, the rest is 20 mil), and I don't pin-test through the residues, either. And I work under a spec that says certain solderballs are acceptable if they're trappped in flux residue. Life is good (for another month, anyway).

I've heard of solderballing problems in other plants with this stuff, and Like I said, we got 'em, but we always did, so this was not remarkable.

A big question though is when did you run the tests? The most recent UP78 is called UP78-M, and it's supposed to ball a lot less than the older stuff. Since we already had beading on our baords, that's what Alpha sent in for the trials. I've never used the original model,so when they tell me that this is a lot better, I ain't got nothin' to compare it to.

On the oven profiles, I've got a mix of linear ramps and soak zones. The higher volume boards got priority on reprofiling. I don't notice a difference in the beading as much as in the residues. They spread out and seem to get "thinner" with the ramp. I can understand from the mechanics of the profile though why it might make more balling. If a hot slump in the soak zone spreads the paste out, it might not coalesce as well. Since we "live with" the beading, I haven't quantified the balling, but now you've got me curious and I might just have to check it out this week.

As for the squeegee speed, definitely go to 2"/min. I did. I thought it sheared down a whole lot better. I even pushed it to 5 and 6, just for fun. It still printed well. We're currently running at 2. It works well, and all our printers can handle it.

So, one question out of pure curiosity. You said to call you nutty for trying more recommendations. Why ya doin' it?

Chrys

reply »

JohnW

#11632

Re: all powerfull UP78..or is it..? - Homeplates..?? | 2 May, 1999

| | | Ok folk's has anyone used Alpha Metal's UP78 solder paste ? | | | | | | Our place is looking to move to that as the way to go, getting rid of the Hereaus 362's and Alpha 737's of the current set up. | | | | | | My question's are really : | | | how is the printability of the paste | | | do I need to further reduce appeture sizes from what I would normally run on say 737 ~ 2 thou reductions | | | solderballs..seen any..? | | | I know alpha are claiming it to be a modern miricle but as yet their technical team cant give me many guildlines on it and the one time it has run in our place it ran badly which is not to say that the paste was to blame but.. | | | so I thought I would ask the 'informed'since I know the power's that be are gonna push it thru without asking anyway's..I thought it would be nice to at least cost new screen's for all the products we run with new appeture reductions if there gonna be needed...ha what fun it must be to make these decisions from upon hi..or am I just being cynical ? | | | | | | John | | | | | | | Hi John! | | | | Your not being cynical, just brutally honest (a quality all upper management fears)! Anyway, UP78.... HATED IT! We've been running a design of experiments (that's DOE for you magazine readers) and the UP78 failed our "Dead Print" experiments and also the "Pin Probability" tests. We printed 25 panels and then let the UP78 sit on the stencil for 45 minutes (to simulate a lunch) and it consistently clogged up the micro BGA openings on our test stencil. It also failed the Pin Probability test on the Pin In Paste portion of our test board. Now all this might not seem too bad, but when I ran this stuff in production, it solder balled to no end! I even had solder balls on SOT23's!!!! That's a first for me! Also had solder fines on all the fine pitch devices. | | | | Alpha then gave us the UP78 PT1 formula. It pasted all our tests but again it solder balled as bad as the regular UP78. Alpha told us that we needed to reduce our stencil opening 10 to 20 percent. So, we had three different stencils made for the same production board. The 1st was a straight 10% reduction on all but the actives. The 2nd was a straight 20% reduction and the third was a 10% reduction using the home plate design on 1206 R's and C's. We ran 4 different pastes on all three stencils. The result was that Alpha did solder ball on ALL three stencils. The size and amount reduced respectively, but still. Now they are telling us we need the "Straight Ramp" oven profile to make this stuff work, as well as increase our squeegee speed from 1"/min to 2"/min!?!?!?!? | | | | I plan to try what they recommend (call me nutty), but I haven't had any problems with the other pastes I tested. I've talked to our Finland plant and they also had the same problems with the balling using Alpha, so at least I know I'm not the only one. | | | | Hope I helped and good luck to you! | | | | KH Factor | | | | | Whoa, Kevin. Major bad experience, dude. I feel for ya. | | I'm a much cheaper date than you. Finest pitch is 18 mil (only one device though, the rest is 20 mil), and I don't pin-test through the residues, either. And I work under a spec that says certain solderballs are acceptable if they're trappped in flux residue. Life is good (for another month, anyway). | | I've heard of solderballing problems in other plants with this stuff, and Like I said, we got 'em, but we always did, so this was not remarkable. | | A big question though is when did you run the tests? The most recent UP78 is called UP78-M, and it's supposed to ball a lot less than the older stuff. Since we already had beading on our baords, that's what Alpha sent in for the trials. I've never used the original model,so when they tell me that this is a lot better, I ain't got nothin' to compare it to. | | On the oven profiles, I've got a mix of linear ramps and soak zones. The higher volume boards got priority on reprofiling. I don't notice a difference in the beading as much as in the residues. They spread out and seem to get "thinner" with the ramp. I can understand from the mechanics of the profile though why it might make more balling. If a hot slump in the soak zone spreads the paste out, it might not coalesce as well. Since we "live with" the beading, I haven't quantified the balling, but now you've got me curious and I might just have to check it out this week. | | As for the squeegee speed, definitely go to 2"/min. I did. I thought it sheared down a whole lot better. I even pushed it to 5 and 6, just for fun. It still printed well. We're currently running at 2. It works well, and all our printers can handle it. | | So, one question out of pure curiosity. You said to call you nutty for trying more recommendations. Why ya doin' it? | | Chrys | | Oh deep joy!, I see there are some mixed feeling's on this wonder paste. Interm's of solder balls and solder fines...the rule in our place is zero!...ha the fun times' I've had at the oven's getting that sorted out! anyhoo sound's like we should be doing our own batch of trials and not blindly doing as the US have commaded..(If I'm on here next week looking for a job u know why!) quick question..what are homeplates..? must be a US term I havent come across it yet

Thanks for the point's..guess I'll et trialing and let you all know how we go

JOhn

reply »

#11633

Homeplates..?? | 3 May, 1999

John: Homeplate is a reference from that American version of cricket ... baseball. In baseball, the pitcher throws the ball towards the batter and the ball must pass over homeplate to be considered to be strike. The ball also must be between the batters knees and shoulders (midchest??) as it crosses homeplate to be a strke. Three strikes, before four non-strikes (balls) or a hit, and you're out. From the SMTnet Glossary:

Home Plate. A five sided, two dimensional, closed shape where three equal length sides form a cube with one side removed and two additional equal length sides that form interior angles of 135�, 90�, and 135�. A picture is worth a thousand words.

Ta

reply »

JohnW

#11634

Re: Homeplates..?? | 3 May, 1999

| John: Homeplate is a reference from that American version of cricket ... baseball. In baseball, the pitcher throws the ball towards the batter and the ball must pass over homeplate to be considered to be strike. The ball also must be between the batters knees and shoulders (midchest??) as it crosses homeplate to be a strke. Three strikes, before four non-strikes (balls) or a hit, and you're out. From the SMTnet Glossary: | | Home Plate. A five sided, two dimensional, closed shape where three equal length sides form a cube with one side removed and two additional equal length sides that form interior angles of 135�, 90�, and 135�. A picture is worth a thousand words. | | Ta | Thanks Dave....I feel all warm and fuzzy now...have to say would rather watch baseball thank cricket any day

Thanks

reply »

Kevin Hussey

#11635

Re: all powerfull UP78..or is it..? | 5 May, 1999

| | | Ok folk's has anyone used Alpha Metal's UP78 solder paste ? | | | | | | Our place is looking to move to that as the way to go, getting rid of the Hereaus 362's and Alpha 737's of the current set up. | | | | | | My question's are really : | | | how is the printability of the paste | | | do I need to further reduce appeture sizes from what I would normally run on say 737 ~ 2 thou reductions | | | solderballs..seen any..? | | | I know alpha are claiming it to be a modern miricle but as yet their technical team cant give me many guildlines on it and the one time it has run in our place it ran badly which is not to say that the paste was to blame but.. | | | so I thought I would ask the 'informed'since I know the power's that be are gonna push it thru without asking anyway's..I thought it would be nice to at least cost new screen's for all the products we run with new appeture reductions if there gonna be needed...ha what fun it must be to make these decisions from upon hi..or am I just being cynical ? | | | | | | John | | | | | | | Hi John! | | | | Your not being cynical, just brutally honest (a quality all upper management fears)! Anyway, UP78.... HATED IT! We've been running a design of experiments (that's DOE for you magazine readers) and the UP78 failed our "Dead Print" experiments and also the "Pin Probability" tests. We printed 25 panels and then let the UP78 sit on the stencil for 45 minutes (to simulate a lunch) and it consistently clogged up the micro BGA openings on our test stencil. It also failed the Pin Probability test on the Pin In Paste portion of our test board. Now all this might not seem too bad, but when I ran this stuff in production, it solder balled to no end! I even had solder balls on SOT23's!!!! That's a first for me! Also had solder fines on all the fine pitch devices. | | | | Alpha then gave us the UP78 PT1 formula. It pasted all our tests but again it solder balled as bad as the regular UP78. Alpha told us that we needed to reduce our stencil opening 10 to 20 percent. So, we had three different stencils made for the same production board. The 1st was a straight 10% reduction on all but the actives. The 2nd was a straight 20% reduction and the third was a 10% reduction using the home plate design on 1206 R's and C's. We ran 4 different pastes on all three stencils. The result was that Alpha did solder ball on ALL three stencils. The size and amount reduced respectively, but still. Now they are telling us we need the "Straight Ramp" oven profile to make this stuff work, as well as increase our squeegee speed from 1"/min to 2"/min!?!?!?!? | | | | I plan to try what they recommend (call me nutty), but I haven't had any problems with the other pastes I tested. I've talked to our Finland plant and they also had the same problems with the balling using Alpha, so at least I know I'm not the only one. | | | | Hope I helped and good luck to you! | | | | KH Factor | | | | | Whoa, Kevin. Major bad experience, dude. I feel for ya. | | I'm a much cheaper date than you. Finest pitch is 18 mil (only one device though, the rest is 20 mil), and I don't pin-test through the residues, either. And I work under a spec that says certain solderballs are acceptable if they're trappped in flux residue. Life is good (for another month, anyway). | | I've heard of solderballing problems in other plants with this stuff, and Like I said, we got 'em, but we always did, so this was not remarkable. | | A big question though is when did you run the tests? The most recent UP78 is called UP78-M, and it's supposed to ball a lot less than the older stuff. Since we already had beading on our baords, that's what Alpha sent in for the trials. I've never used the original model,so when they tell me that this is a lot better, I ain't got nothin' to compare it to. | | On the oven profiles, I've got a mix of linear ramps and soak zones. The higher volume boards got priority on reprofiling. I don't notice a difference in the beading as much as in the residues. They spread out and seem to get "thinner" with the ramp. I can understand from the mechanics of the profile though why it might make more balling. If a hot slump in the soak zone spreads the paste out, it might not coalesce as well. Since we "live with" the beading, I haven't quantified the balling, but now you've got me curious and I might just have to check it out this week. | | As for the squeegee speed, definitely go to 2"/min. I did. I thought it sheared down a whole lot better. I even pushed it to 5 and 6, just for fun. It still printed well. We're currently running at 2. It works well, and all our printers can handle it. | | So, one question out of pure curiosity. You said to call you nutty for trying more recommendations. Why ya doin' it? | | Chrys | | Hi Chrys,

Sorry for getting back to you so late, I've been wearing a lot of hats lately and well...you know. Anyway, I have in my hot little engineering hands, a 700 gram cartridge of Alpha's Ultraprint UP87 PT1. The mfg date is March 11, 1999, expires Sept 11, 1999. It is lot # 90311042. We've been running paste testes since February. I believe this paste was a Beta paste at the time we received it, maybe not, we've tried a varity of Alpha pastes lately.

Anyhoo, we've had an engineer here who has been working with Alpha to make their paste work and we've tried the M series as well. Still had more solder balls, and bigger solder balls than any of the other pastes we tried. Also had fines around the fine pitch stuff. Our current paste has some solder balls as well, and we live with em' as long as they meet spec. My big problem is our group has to pick a paste that will be used at all our facilities, so I want to pick a paste that out performs what we all currently are using. I'm sure no matter which paste I pick, the other plants will blame all their yield fall out on the "new paste", but I think the grace period for this is only 6 weeks, right? That's the reason I'm going to contue testing the Alpha with the reccomendations they give us. If I don't, Murphy tells me some manager will ask me "why didn't you" and I'll be forced to do it anyway.

Thanks for the squeegee info. I'll be running more tests later this week (weekend) and I'll let ya know how things go.

reply »

wayne sanita

#11636

Re: all powerfull UP78..or is it..? - Homeplates..?? | 8 May, 1999

hello, i have been using up-78 ultraprint for over a year now. at first we were getting lots of solder balls mainly on 0805's. this happened with all paste we used, too much solder under component leads. i have been using apertures reduced 10% homeplated with great results ,no solder balls!!! also i reduce ic pitches 32mil and down 15% on width but no less than 9mil,this eliminated bridging. i can usually get 8 hours out of this paste but keep an eye on the humidity if not a closed environment.

| | | | Ok folk's has anyone used Alpha Metal's UP78 solder paste ? | | | | | | | | Our place is looking to move to that as the way to go, getting rid of the Hereaus 362's and Alpha 737's of the current set up. | | | | | | | | My question's are really : | | | | how is the printability of the paste | | | | do I need to further reduce appeture sizes from what I would normally run on say 737 ~ 2 thou reductions | | | | solderballs..seen any..? | | | | I know alpha are claiming it to be a modern miricle but as yet their technical team cant give me many guildlines on it and the one time it has run in our place it ran badly which is not to say that the paste was to blame but.. | | | | so I thought I would ask the 'informed'since I know the power's that be are gonna push it thru without asking anyway's..I thought it would be nice to at least cost new screen's for all the products we run with new appeture reductions if there gonna be needed...ha what fun it must be to make these decisions from upon hi..or am I just being cynical ? | | | | | | | | John | | | | | | | | | | Hi John! | | | | | | Your not being cynical, just brutally honest (a quality all upper management fears)! Anyway, UP78.... HATED IT! We've been running a design of experiments (that's DOE for you magazine readers) and the UP78 failed our "Dead Print" experiments and also the "Pin Probability" tests. We printed 25 panels and then let the UP78 sit on the stencil for 45 minutes (to simulate a lunch) and it consistently clogged up the micro BGA openings on our test stencil. It also failed the Pin Probability test on the Pin In Paste portion of our test board. Now all this might not seem too bad, but when I ran this stuff in production, it solder balled to no end! I even had solder balls on SOT23's!!!! That's a first for me! Also had solder fines on all the fine pitch devices. | | | | | | Alpha then gave us the UP78 PT1 formula. It pasted all our tests but again it solder balled as bad as the regular UP78. Alpha told us that we needed to reduce our stencil opening 10 to 20 percent. So, we had three different stencils made for the same production board. The 1st was a straight 10% reduction on all but the actives. The 2nd was a straight 20% reduction and the third was a 10% reduction using the home plate design on 1206 R's and C's. We ran 4 different pastes on all three stencils. The result was that Alpha did solder ball on ALL three stencils. The size and amount reduced respectively, but still. Now they are telling us we need the "Straight Ramp" oven profile to make this stuff work, as well as increase our squeegee speed from 1"/min to 2"/min!?!?!?!? | | | | | | I plan to try what they recommend (call me nutty), but I haven't had any problems with the other pastes I tested. I've talked to our Finland plant and they also had the same problems with the balling using Alpha, so at least I know I'm not the only one. | | | | | | Hope I helped and good luck to you! | | | | | | KH Factor | | | | | | | | Whoa, Kevin. Major bad experience, dude. I feel for ya. | | | | I'm a much cheaper date than you. Finest pitch is 18 mil (only one device though, the rest is 20 mil), and I don't pin-test through the residues, either. And I work under a spec that says certain solderballs are acceptable if they're trappped in flux residue. Life is good (for another month, anyway). | | | | I've heard of solderballing problems in other plants with this stuff, and Like I said, we got 'em, but we always did, so this was not remarkable. | | | | A big question though is when did you run the tests? The most recent UP78 is called UP78-M, and it's supposed to ball a lot less than the older stuff. Since we already had beading on our baords, that's what Alpha sent in for the trials. I've never used the original model,so when they tell me that this is a lot better, I ain't got nothin' to compare it to. | | | | On the oven profiles, I've got a mix of linear ramps and soak zones. The higher volume boards got priority on reprofiling. I don't notice a difference in the beading as much as in the residues. They spread out and seem to get "thinner" with the ramp. I can understand from the mechanics of the profile though why it might make more balling. If a hot slump in the soak zone spreads the paste out, it might not coalesce as well. Since we "live with" the beading, I haven't quantified the balling, but now you've got me curious and I might just have to check it out this week. | | | | As for the squeegee speed, definitely go to 2"/min. I did. I thought it sheared down a whole lot better. I even pushed it to 5 and 6, just for fun. It still printed well. We're currently running at 2. It works well, and all our printers can handle it. | | | | So, one question out of pure curiosity. You said to call you nutty for trying more recommendations. Why ya doin' it? | | | | Chrys | | | | Oh deep joy!, I see there are some mixed feeling's on this wonder paste. Interm's of solder balls and solder fines...the rule in our place is zero!...ha the fun times' I've had at the oven's getting that sorted out! | anyhoo sound's like we should be doing our own batch of trials and not blindly doing as the US have commaded..(If I'm on here next week looking for a job u know why!) | quick question..what are homeplates..? must be a US term I havent come across it yet | | Thanks for the point's..guess I'll et trialing and let you all know how we go | | JOhn | |

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