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

Printed Circuit Board Assembly & PCB Design Forum

SMT electronics assembly manufacturing forum.


Selective Wave Soldering

Gary Simbulan

#16320

Selective Wave Soldering | 7 April, 1998

Good Morning everyone. Per repeated suggestions I have been reading back issues of SMT and Circuits Assembly magazines. I have just read an article concerning selective wave soldering which I understand is to be used when active SMTcomponents are are reflowed onto both sides of the board. The board is then mounted in a fixture which covers the SMT components and allows the wave to flow the through hole parts. Only days later I was requested to investigate this process for a new, very dense, design. I am looking for any information reguarding the design parameters for these "Pallets", materials, clearances, and specifcally any vendors or fab shops with experience in design or fabrication. On a completely different subject, I thank all of you who responded or e-mailed me concerning my question about cleaning ceramic substrates. I am now in the process of collecting a large amount of mostly contradictory information on the subject. I'll revisit this when I have some valid test results Thanks for any help you can give. Gary

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Steve A

#16323

Re: Selective Wave Soldering | 7 April, 1998

| Good Morning everyone. Per repeated suggestions I have been reading back issues of SMT and Circuits Assembly magazines. I have just read an article concerning selective wave soldering which I understand is to be used when active SMTcomponents are are reflowed onto both sides of the board. The board is then mounted in a fixture which covers the SMT components and allows the wave to flow the through hole parts. Only days later I was requested to investigate this process for a new, very dense, design. I am looking for any information reguarding the design parameters for these "Pallets", materials, clearances, and specifcally any vendors or fab shops with experience in design or fabrication. | On a completely different subject, I thank all of you who responded or e-mailed me concerning my question about cleaning ceramic substrates. I am now in the process of collecting a large amount of mostly contradictory information on the subject. I'll revisit this when I have some valid test results | Thanks for any help you can give. | Gary Gary, Check with some of the larger SMT fixture makers such as EMC Global Technologies 215-340-0650 or SP Precision International 503-357-9228. They should be able to help you iron out a design, or do a full turn key job for you. Steve A

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Chrys

#16322

Re: Selective Wave Soldering | 7 April, 1998

Be careful about the material you choose. All the materials out there are basically glass-filled epoxy composites, but they are different blends with different fillers. Some of them have carbon in the matrix to make them ESD safe, but it also shortens their lives. - ECP Plus (grey colored) doesn't hold up real well to fluxes, thermal cycling, and production abuse. It degrades and turns brown as it starts to fail, and the corners of the pallets get worn off very easily by conveyor and other handling. - Delmat (greenish blue or ESD safe black) is a better material, but more expensive. - The best I've found is Durostone (dark blue or black), which is (believie it or not) less expensive than Delmat and holds up better. The reason the materials break down is because they all have some degree of porosity, and water/alcohol from the flux gets inside and expands or outgasses as the pallet is heated. If you want to preserve the quality of the pallets, you can get them coated with a special coating that serves three purposes: 1) It's conductive so It's ESD safe (then you can use the stronger material) 2) It keeps the flux out 3) It keeps the glass fibers in and away from operators' hands. I've been using a shop in New Jersey for selective soldering pallets for about eight years. They do a great job. I'll email you their name and number. Chrys

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Ryan Jennens

#16321

Re: Selective Wave Soldering | 9 April, 1998

:Gary- DMI International does a great job. They are fast, well-priced, and produce excellent boards. They really work with you to get the design you need. I'll include a link. DMI International 1-800-886-1468

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Jim Gleason

#16324

Re: Selective Wave Soldering | 21 October, 1998

Fyi,

I just came across this the other day and you should look GSC, info@gogsc.com. They have been around for ages and do a great job for Lucnet.

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Tom Gervascio

#16325

Re: Selective Wave Soldering | 12 January, 1999

| | Good Morning everyone. Per repeated suggestions I have been reading back issues of SMT and Circuits Assembly magazines. I have just read an article concerning selective wave soldering which I understand is to be used when active SMTcomponents are are reflowed onto both sides of the board. The board is then mounted in a fixture which covers the SMT components and allows the wave to flow the through hole parts. Only days later I was requested to investigate this process for a new, very dense, design. I am looking for any information reguarding the design parameters for these "Pallets", materials, clearances, and specifcally any vendors or fab shops with experience in design or fabrication. | | On a completely different subject, I thank all of you who responded or e-mailed me concerning my question about cleaning ceramic substrates. I am now in the process of collecting a large amount of mostly contradictory information on the subject. I'll revisit this when I have some valid test results | | Thanks for any help you can give. | | Gary | Gary, | Check with some of the larger SMT fixture makers | such as EMC Global Technologies 215-340-0650 or | SP Precision International 503-357-9228. | They should be able to help you iron out a design, | or do a full turn key job for you. | Steve A

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Tom Gervascio

#16326

Re: Selective Wave Soldering | 12 January, 1999

I've been using selective soldering process for about 18 months. The major problem concerns tight spacing- the distance between the SMT pads to be masked and the thru hole leads to be wave soldered should be no less than 0.150 inches. Keep the walls in the pallet as thick as possible- if less than 0.040 thick we have had problems with the pallet material breaking down and permitting solder flooding. Also keep the total pallet thickness below 8 mm total thickness or the pallet will run too deep in the wave- believe me this is a problem.

| | | Good Morning everyone. Per repeated suggestions I have been reading back issues of SMT and Circuits Assembly magazines. I have just read an article concerning selective wave soldering which I understand is to be used when active SMTcomponents are are reflowed onto both sides of the board. The board is then mounted in a fixture which covers the SMT components and allows the wave to flow the through hole parts. Only days later I was requested to investigate this process for a new, very dense, design. I am looking for any information reguarding the design parameters for these "Pallets", materials, clearances, and specifcally any vendors or fab shops with experience in design or fabrication. | | | On a completely different subject, I thank all of you who responded or e-mailed me concerning my question about cleaning ceramic substrates. I am now in the process of collecting a large amount of mostly contradictory information on the subject. I'll revisit this when I have some valid test results | | | Thanks for any help you can give. | | | Gary | | Gary, | | Check with some of the larger SMT fixture makers | | such as EMC Global Technologies 215-340-0650 or | | SP Precision International 503-357-9228. | | They should be able to help you iron out a design, | | or do a full turn key job for you. | | Steve A | |

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