| | I am running composite fixtures on my wave solder machine and after about 500 passes each (1 month)they are showing serious signs of wear in that the composite surface is bubbling up and glass fibers are also starting to show. | | The problem here is that the fixtures are starting to smell really bad when they exit the machine since they are holding more flux due to their now more porous surface. Handling the fixtures is also an issue since they feel more like R-10 home insulation to the bare hands than composite. Does anyone else have this problem? WHat is causing it? Fixtures are too expensive to constantly relace. | | (We use a no-clean Kester 958 flux and run at 4 ft/min with (3) zones at ~300C preheat (4 feet of preheat). Solder temp is 500F.) Spray fluxer. | | THanks, Dave | Dave, | Assuming you are running one of the popular engineered composite materials such as CDM 68.650, CDM -ESD 68.610, G10 or ECP Plus, there are a few parameters that would decrease pallet life. Obviously the wavesolder could reduce the pallet life especially if you are using bottom IR heaters that are cranked up high. | The length of your preheater (number of zones), would regulate your preheater settings. | Another major factor is the thickness of your pallet. This is a tough one. You can increase pallet thickness and gain more life out of the pallets, however you need to make sure that you can achieve proper wave height to sufficiently solder the board. | We have pallets that are 8mm and 10mm thick, but then again we have forced convection/IR assist preheaters, and both Lambda and Chip waves with nitrogen blanket to support the thick pallets and increased wave height. (as well as a good tech department to support the additional dross created by the increased solder exposure) | Unfortunately we have not found a way to have our cake and eat it too! | Good Luck.. | Steve A Dave, How thick are your PCBs? Do you have adequate topside preheat or are the bottom preheaters turned up to ensure proper filleting on the top side? Rob
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