PCB Warpage in Wave Soldering Machines?

do you pre-heat the PCB's before the wave?

have you looked at alternative soldering technology for your product?

something like IR-reflow, Selective soldering.

Board warpage is a BAD thing to have, especially when you have chip caps on the PCB, these little buggers will give you no end of problems if they are not treated with respect.

Could you provide more detailed information on DMI in Canada? Where? Web Page?

Complete name? Thanks, peh

Titanium stiffeners work the best provided there is edge clearance. leave them on for a couple of minutes while the board cools. If no edge is available maybe a bar on the top of the board with screws using exsisting holes in board.

If no space is available, get some fiberglass g10 0.093" thick and route out the shape of the board leaving about 1/16" all around the edges (0.032 thk) that you can set the board on. This is a home made pallet. Put the board in the fixture and wave solder the fixture.

Remember: only titanium or stainless should touch the solder and never aluminium!

I have experienced the same problem with thin and large surface PCBs.

We purchase wave solder pallets from a company called Stone Mountain Tool.

These pallet are machined to your specification from a glass filled resin that will hold up to wave solder temperatures (525F) repeatedly for 8-10 years. The PCB is carried on the pallet allowing it to be exposed to the solder wave (as does the pallet) to your desired depth. The edges of the PCB are held in place to prevent warpage using simple half turn toggles. Contact is Stone Mountain Tool, Inc. 480 Gees Mill Business Court Conyers, Georgia 30013 Phone 770-929-0166 Fax 770-929-0226

Web page www.stonemountaintool.com Hope this helps. if you would like pictures of our design reply and I can provide. peh

It is unclear from your post if the boards are warped prior to entering the wave solder machine. If they are warping during the process check to see if they are a multi-layer board with a large copper plane (usually ground) on one of the outer or near outer layers, while the rest of the layers are circuit runs or pads. Uneven copper on one side of the board will often cause this to happen and the fix is to balance the board layers by putting another large copper plane on the other side or balancing the copper throughout the board.

Other areas to look out for are the route out areas for electrical isolation, especially when you have it under transformers.

The problem I mostly get is designers placing HUGE components on a PCB, changing the dynamics of a PCB as it heats and cools, causing the board to warp and bend.

I had 1 board from a customer yesterday, it had the isolation route, the components were about 50mm (2") high, and they needed it tested with MDA (Checksum 2270/71)

The issue I have is several things, warped boards and trying to seal them for vacuum pull down, if using a HDG (hold down gate) trying to get the fingers down between the high components (including the arc from the hinge) and also minimising flex of the DUT to stop cracking components.