Jig for PCB

Mark,

I am having difficulty picturing exactly what you are doing, but I hope this helps. We occasionally use jigs through SMT, usually because the board is too small/thin to fit the smallest rail width. In such situations, we normally make the jig out of FR4 (standard board material) with no copper. Simply cut out a window slightly bigger than your board (for clearence). Use screws or rivets to fasten strips of FR4 on the bottom to create a lip for the board to sit on. You will still need some extra heat in your oven, but nowhere near as much as you would trying to heat 6mm thich aluminium.

Jon.

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We use materials such as G10, durapol, or FR4. We put a lot of holes in the fixtures so that only enough material is left to support the board during reflow to prevent sag/ warp or whatever. We also try and keep all bot side material in unpopulated areas of the assembly.

Russ

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Outside the box:

Can you retro your oven with a belt chain combo? I always order my ovens this way just in case. No pallet or carrier needed then. Can justify retro against the cost of the pallet or carrier.

Two part epoxy instead of heat cure? May also save you time.

Two part heat cure, where the epoxy starts to cure, then you can hang in the oven without the PCB moving.

Stand alone oven where you just place the units in, let em cure that way. Not pass through but without knowing your process, it may work.

Use small clamps to keep the two materials together?

Add alignment pins?

Just some other ideas.

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We don't understand why your aluminum pallet requires high temperature. Is it that you don't want to slow the conveyor?

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I solder a lot of differnt products throught a Reflow oven that are non PCB baised Axial leaded components typicaly, mounted vertically in jigs. where i can for cost reasons I use aluminium jigs but you have to experiment with the thermal mass and design quite a lot. A technically better solution is a machinable ceramic but can be damn expensive. Large flat plates are undesiable as you cant achive the same temperature profile over the full surface, if your design allows this can be improved by machining 3mm slots that go right through, across the plate every 10 or 15mm

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