Will somebody explain HASL please

Will somebody please explain HASL (here). Thanks.

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| Will somebody please explain HASL (here). Thanks. Tryin: HASL: Hot Air Solder Leveled. A board fabrication process that applies an oxidation preventing solder coating to copper pads on the board. Dave F

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| | Will somebody please explain HASL (here). Thanks. | Tryin: HASL: Hot Air Solder Leveled. A board fabrication process that applies an oxidation preventing solder coating to copper pads on the board. Dave F You do this to keep the green stuff (solder mask?) from coating the copper? If so, do you do this so that in later steps you can apply gold or nickel and gold? It seems like HASL comes up along eith gold plating questions. Thnaks in advance for your help.

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| | | Will somebody please explain HASL (here). Thanks. | | Tryin: HASL: Hot Air Solder Leveled. A board fabrication process that applies an oxidation preventing solder coating to copper pads on the board. Dave F | You do this to keep the green stuff (solder mask?) from coating the copper? If so, do you do this so that in later steps you can apply gold or nickel and gold? It seems like HASL comes up along eith gold plating questions. | Thnaks in advance for your help. HASL is hot air solder leveling. Copper conductor surfaces must be covered with either a metal (solder as tin/lead as an example) or an organic coating (resin based as an example). These coatings are applied to prevent, or minimize solder termination area (pads)oxidation that inhibits solderability and acceptable solder joint formation. Solder mask is applied to a PCB's surface to prevent solder bridging between two conductors during soldering operations. Both solder mask and some conductor surface coating may be used together. Other metal coatings may include gold, silver, nickel, tin, or tin lead plating (differently applied than HASL). This is why you are hearing and seeing so much discussion about HASL and its alternatives. Alternatives are needed, it is felt by many in industry, to provide better solderability, higher quality solder joints, and a flatter surface on which to mount very small or fine pitch surface mount devices (SMD's). The HASL process is performed on a bare copper board (usually with a wet photoimageable solder mask covering all areas not to be soldered). The board is dipped (for simplicity's sake) first into a flux, then into molten solder, and finally is "leveled" by bringing the board out of the operation through hot air knives (high pressure air jets forcing air to level the still molten solder over the coated areas). This process has limitations as often oxides are left on the bare copper surface that are not always removed during the solder fluxing and solder coating phases. Also, intermetallics, in excessive amounts, are often formed preventing adequate solderability during assembly operations. The uneven surface topography results from the hot air knives doing their thing much as wind creates wave activity on lakes or oceans. There's a bunch more, but this will do for now. No more confusion, right? Earl Moon

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| Will somebody please explain HASL (here). Thanks. Tryin': Check the following thread on SMTNet. Dave F Green coating and through-hole plating - Xingsheng 15:13:05 8/11/98 (3)

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HASL: (hot air solder leveling) is a process used to cover the Cu. Either Sn/Pb is used or Ni/Au or some other combo. In one case you create a land pad and in the other (with resin)you cover the Cu so that you only have a "trace." Is that correct so far? You do this to prevent the copper from oxidizing? If so, how does a problem with the copper affect how well the Sn/Pb pad will accept solder? Is HASL done for each PCB layer? And then solder mask is applied on the outside layers (top side and bottom if Dbl sided SMT)? I can sort of picture a layer of copper going through a wavesolder machine. But you have to cut away most of the copper, right? How else would you get traces? Wow, I hope I'm not askin' too many questions here. I really appreciate all the knowledge at this forum. -Tryin' PS: It seems like board houses have a lot of problems on their hands.

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| HASL: (hot air solder leveling) is a process used to cover the Cu. Either Sn/Pb is used or Ni/Au or some other combo. In one case you create a land pad and in the other (with resin)you cover the Cu so that you only have a "trace." Is that correct so far? | You do this to prevent the copper from oxidizing? If so, how does a problem with the copper affect how well the Sn/Pb pad will accept solder? | Is HASL done for each PCB layer? And then solder mask is applied on the outside layers (top side and bottom if Dbl sided SMT)? | I can sort of picture a layer of copper going through a wavesolder machine. But you have to cut away most of the copper, right? How else would you get traces? | Wow, I hope I'm not askin' too many questions here. I really appreciate all the knowledge at this forum. | -Tryin' | PS: It seems like board houses have a lot of problems on their hands. Board shops and us, the user, have a lot on our hands. As far as getting traces - this is done using an etch resist before solder mask and the HASL processes are performed. With tin/lead plated boards, the tin lead is an etch resist that is only stripped away in areas where traces are not wanted. With SMOBC and HASL, the etch resist is a polyer coating or film layer that is photoimaged and stripped away exposing copper to be removed leaving only traces as it is done on inner layers but no solder is applied to inners. Keep asking. There's always someone willing to answer, Earl Moon

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| Board shops and us, the user, have a lot on our hands. As far as getting traces - this is done using an etch resist before solder mask and the HASL processes are performed. So when in the process is HASL performed??

| With tin/lead plated boards, the tin lead is an etch resist that is only stripped away in areas where traces are not wanted. With SMOBC and HASL, the etch resist is a polyer coating or film layer that is photoimaged and stripped away exposing copper to be removed leaving only traces as it is done on inner layers but no solder is applied to inners. Is HASL, then, done at the final stages? The PCB is already made and you're just doing this to keep the pads/fingers fresh?

I gettin' more confused than I already was. But I know I;m on the right road if Earl's drivin' -Tryin' (I wish I knew where steve gets all those quirky URL links) | Keep asking. There's always someone willing to answer, | Earl Moon

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| | | Board shops and us, the user, have a lot on our hands. As far as getting traces - this is done using an etch resist before solder mask and the HASL processes are performed. | So when in the process is HASL performed?? | | | With tin/lead plated boards, the tin lead is an etch resist that is only stripped away in areas where traces are not wanted. With SMOBC and HASL, the etch resist is a polyer coating or film layer that is photoimaged and stripped away exposing copper to be removed leaving only traces as it is done on inner layers but no solder is applied to inners. | Is HASL, then, done at the final stages? The PCB is already made and you're just doing this to keep the pads/fingers fresh? | | I gettin' more confused than I already was. But I know I;m on the right road if Earl's drivin' | -Tryin'

| (I wish I knew where steve gets all those quirky URL links) | | Keep asking. There's always someone willing to answer, | | Earl Moon Hey babe, You got it. It ain't easy, but you did it. It's the last stage, almost, but who needs the rest? Look up your local circus board supplier and go pay him/her a visit. You'll now be astonished at the wonders and delights becknoning. Of course, it's not like in the old days when everyone gathered 'round yonder plating line and stayed high. Not me though. Anyway, go visit a shop and see for yourself. Earl Moon

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What conditions make Earl Moon say "damn, why can't XXX get the HASL right? Just look at this crummy board. Get a RMA No. Stat."

| | | Board shops and us, the user, have a lot on our hands. As far as getting traces - this is done using an etch resist before solder mask and the HASL processes are performed. | | So when in the process is HASL performed?? | | | | | With tin/lead plated boards, the tin lead is an etch resist that is only stripped away in areas where traces are not wanted. With SMOBC and HASL, the etch resist is a polyer coating or film layer that is photoimaged and stripped away exposing copper to be removed leaving only traces as it is done on inner layers but no solder is applied to inners. | | Is HASL, then, done at the final stages? The PCB is already made and you're just doing this to keep the pads/fingers fresh? | | | | I gettin' more confused than I already was. But I know I;m on the right road if Earl's drivin' | | -Tryin' | | | (I wish I knew where steve gets all those quirky URL links) | | | Keep asking. There's always someone willing to answer, | | | Earl Moon | Hey babe, | You got it. It ain't easy, but you did it. It's the last stage, almost, but who needs the rest? | Look up your local circus board supplier and go pay him/her a visit. You'll now be astonished at the wonders and delights becknoning. Of course, it's not like in the old days when everyone gathered 'round yonder plating line and stayed high. Not me though. | Anyway, go visit a shop and see for yourself. | Earl Moon

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| What conditions make Earl Moon say "damn, why can't XXX get the HASL right? Just look at this crummy board. Get a RMA No. Stat." I don't have to get that frustrated because I deal with those who do it right most of the time. You have to consider the source (process). It ain't ever completely right. It has inherent problems causing solderability and solder joint problems. It's topography isn't flat, etc.. These factors make me constantly look for alternatives to HASL and other processes/products that don't satisfy, and they're always just visible on the horizon. Some fabricators to it as well as can be because they manage processes to prevent defect instead of reacting to results as defect. Many don't have a clue about process management and defect prevention. So, you gots to evaluate and qualify your suppliers to assure quality meeting your requirements before placing the order, so you don't have to deal with RMA, DMR, MRB, and corrective action because you stop reacting when you start preventing. Earl Moon | | | | | | Board shops and us, the user, have a lot on our hands. As far as getting traces - this is done using an etch resist before solder mask and the HASL processes are performed. | | | So when in the process is HASL performed?? | | | | | | | With tin/lead plated boards, the tin lead is an etch resist that is only stripped away in areas where traces are not wanted. With SMOBC and HASL, the etch resist is a polyer coating or film layer that is photoimaged and stripped away exposing copper to be removed leaving only traces as it is done on inner layers but no solder is applied to inners. | | | Is HASL, then, done at the final stages? The PCB is already made and you're just doing this to keep the pads/fingers fresh? | | | | | | I gettin' more confused than I already was. But I know I;m on the right road if Earl's drivin' | | | -Tryin' | | | | | (I wish I knew where steve gets all those quirky URL links) | | | | Keep asking. There's always someone willing to answer, | | | | Earl Moon | | Hey babe, | | You got it. It ain't easy, but you did it. It's the last stage, almost, but who needs the rest? | | Look up your local circus board supplier and go pay him/her a visit. You'll now be astonished at the wonders and delights becknoning. Of course, it's not like in the old days when everyone gathered 'round yonder plating line and stayed high. Not me though. | | Anyway, go visit a shop and see for yourself. | | Earl Moon

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I know you are "Trying' to learn", however, your e-mail addresses are not real, especially the ones@smtnet.com. This forum and the whole SMTnet is geared toward professional use only. Your correct name and email address will allow other SMTneters and the SMTnet staff to communicate with you outside the Forum. While most other non-professional forums do not check or care if you place a "fake" name or email, we do. We are especially offended that you provided fake e-mail addresses @smtnet.com. Besides taking up our server resources, your fake addresses are an infringment to our reputable name. We appreciate your participation in SMTnet's services, and hope you come back. Just please remember that this is a professionally geared forum and full cooperation is required and much appreciated by all. Thanks, Cunli

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Thanks for the great info, man!!

| | What conditions make Earl Moon say "damn, why can't XXX get the HASL right? Just look at this crummy board. Get a RMA No. Stat." | I don't have to get that frustrated because I deal with those who do it right most of the time. You have to consider the source (process). It ain't ever completely right. It has inherent problems causing solderability and solder joint problems. It's topography isn't flat, etc.. These factors make me constantly look for alternatives to HASL and other processes/products that don't satisfy, and they're always just visible on the horizon. | Some fabricators to it as well as can be because they manage processes to prevent defect instead of reacting to results as defect. Many don't have a clue about process management and defect prevention. So, you gots to evaluate and qualify your suppliers to assure quality meeting your requirements before placing the order, so you don't have to deal with RMA, DMR, MRB, and corrective action because you stop reacting when you start preventing.

| Earl Moon | | | | | | | | | Board shops and us, the user, have a lot on our hands. As far as getting traces - this is done using an etch resist before solder mask and the HASL processes are performed. | | | | So when in the process is HASL performed?? | | | | | | | | | With tin/lead plated boards, the tin lead is an etch resist that is only stripped away in areas where traces are not wanted. With SMOBC and HASL, the etch resist is a polyer coating or film layer that is photoimaged and stripped away exposing copper to be removed leaving only traces as it is done on inner layers but no solder is applied to inners. | | | | Is HASL, then, done at the final stages? The PCB is already made and you're just doing this to keep the pads/fingers fresh? | | | | | | | | I gettin' more confused than I already was. But I know I;m on the right road if Earl's drivin' | | | | -Tryin' | | | | | | | (I wish I knew where steve gets all those quirky URL links) | | | | | Keep asking. There's always someone willing to answer, | | | | | Earl Moon | | | Hey babe, | | | You got it. It ain't easy, but you did it. It's the last stage, almost, but who needs the rest? | | | Look up your local circus board supplier and go pay him/her a visit. You'll now be astonished at the wonders and delights becknoning. Of course, it's not like in the old days when everyone gathered 'round yonder plating line and stayed high. Not me though. | | | Anyway, go visit a shop and see for yourself. | | | Earl Moon

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| Thanks for the great info, man!! | | | | | What conditions make Earl Moon say "damn, why can't XXX get the HASL right? Just look at this crummy board. Get a RMA No. Stat." | | I don't have to get that frustrated because I deal with those who do it right most of the time. You have to consider the source (process). It ain't ever completely right. It has inherent problems causing solderability and solder joint problems. It's topography isn't flat, etc.. These factors make me constantly look for alternatives to HASL and other processes/products that don't satisfy, and they're always just visible on the horizon. | | Some fabricators to it as well as can be because they manage processes to prevent defect instead of reacting to results as defect. Many don't have a clue about process management and defect prevention. So, you gots to evaluate and qualify your suppliers to assure quality meeting your requirements before placing the order, so you don't have to deal with RMA, DMR, MRB, and corrective action because you stop reacting when you start preventing. | | | Earl Moon | | | | | | | | | | | | Board shops and us, the user, have a lot on our hands. As far as getting traces - this is done using an etch resist before solder mask and the HASL processes are performed. | | | | | So when in the process is HASL performed?? | | | | | | | | | | | With tin/lead plated boards, the tin lead is an etch resist that is only stripped away in areas where traces are not wanted. With SMOBC and HASL, the etch resist is a polyer coating or film layer that is photoimaged and stripped away exposing copper to be removed leaving only traces as it is done on inner layers but no solder is applied to inners. | | | | | Is HASL, then, done at the final stages? The PCB is already made and you're just doing this to keep the pads/fingers fresh? | | | | | | | | | | I gettin' more confused than I already was. But I know I;m on the right road if Earl's drivin' | | | | | -Tryin' | | | | | | | | | (I wish I knew where steve gets all those quirky URL links) | | | | | | Keep asking. There's always someone willing to answer, | | | | | | Earl Moon | | | | Hey babe, | | | | You got it. It ain't easy, but you did it. It's the last stage, almost, but who needs the rest? | | | | Look up your local circus board supplier and go pay him/her a visit. You'll now be astonished at the wonders and delights becknoning. Of course, it's not like in the old days when everyone gathered 'round yonder plating line and stayed high. Not me though. | | | | Anyway, go visit a shop and see for yourself. | | | | Earl Moon I tried your email and couldn't send. Wondered if you would like copy of article I wrote about HASL. Earl Moon

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