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Wave soldering PWB with foil surface.

Joel Kouba

#19672

Wave soldering PWB with foil surface. | 24 April, 2002

We have been trying to flow some PWBs with pth that have foil on both the primary and secondary sides. What would be the best way to setup the wave solder machine to accomplish this task. for example (solder temp,conveyor angle,conveyor speed)

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RDR

#19674

Wave soldering PWB with foil surface. | 24 April, 2002

I may be stupid but what exactly do you mean by "foil" on both sides? Are you having trouble with top flow? bridging? Are you using water soluble or noclean? Are you also waving SMT components? Anyway, normally the solder temp should be 460 - 500 F(63/37 alloy), the conveyor angle should be between 5-7 deg. As far as conveyor speed, this is dependant upon your dwell time over the wave and your ability to reach adequate top side preheat temp. (usually about 220 F.) The dwell time should not exceed 5 seconds normally. these are basic guidelines and as far as the correct preheat and dwell time you should review your flux manufacturers data.

Hope this helps a little Russ

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#19680

Wave soldering PWB with foil surface. | 24 April, 2002

Sounds like you are involved in a very neat project.

Suggestions: * Get a copy to Bob Willis� wave solder machine set-up procedure [ http://www.eps.com ]. It�s a little dated, but it�s a good starting point nonetheless. * Search the fine SMTnet Archives. There is tons of good advice there on wave soldering. * Get a copy of your flux supplier recommendations. Ask them for help in understanding in determining the activity of your flux, understanding when to replace your flux, measuring flux density, etc. * Read the operating manual for the machine and follow the manufacturer�s maintenance recommendations. * Buy a piece of fireplace glass at the local glass store. The stuff is tempered to take the heat. Get it cut to fit your typical conveyor width. It'll cost around $30 and worth every nickel. Use the plate to observe even fluxing and check the wave for dwell and uniform contact. * Learn how to do designed experiments [DOE]. => Search the fine SMTnet Archives.

Guidelines * Control: Flux specific gravity, preheater temp, conveyer speed, solder temperature. * Two most important parameters are: solder temperature & dwell time * Contact time. The optimum contact (dwell) time in the wave should be 2 seconds. Contact bandwidth is a function of conveyor speed. For an example, 5cm of contact band width at 150cm/min conveyor speed will give you 2 seconds of contact time and 2cm of contact band width at 60cm/min conveyor speed also delivers 2 seconds dwell (contact) time. [From a Sandia Laboratories chart] * Immersion depth (1/3 to 2/3 of the board) has the least impact of any variable in wave soldering * Pot temperature: 460-480�F [240-260�C]. * Topside temperature entering wave: Aqueous flux - 180-220�F [82-104�C] No-clean flux � 200-230�F [93-110�C] * Conveyor slope: 8�

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RDR

#19686

Wave soldering PWB with foil surface. | 25 April, 2002

Great info Dave!!

Do you know what is meant by "foil"? I am really curious?

Russ

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Shawn

#19687

Wave soldering PWB with foil surface. | 25 April, 2002

What he is talking about when he said "foil" is the top and bottom side of the board has a layer that is like a ground plane with no solder resist covering it. It is etched out around the pads that no not need a connection and have a small bride or trace to the pads that do connect to it. Alot of older board designs that I have seen use this type of technology. Some would only have exposed external traces running from point to point but this one as I had said is more like a ground plane where only the unnecessary areas are etched out.

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Bob Willis

#19710

Wave soldering PWB with foil surface. | 29 April, 2002

Many thanks for the name check Frank but its http://www.bobwillis.co.uk not eps.com

Any suggestions recomendation on topics to include to up date the wave soldering set guide would be appriciated.

Bob Willis

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