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How to Make Polytetrafluoroethylene Circuit Board Without Falling off and Foaming?

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  In printed circuit board,polytetrafluoroethylene board is a kind of high frequency board,which can withstand high temperature,corrosion,high insulation and other advantages.It is considered that the advantage of this board is used to process circuit board in many military products.However,due to the particularity of the plate,the surface of the substrate is smooth and the material is soft,which brings difficulties in the processing.Among them,the adjustable ones are resistance welding and milling shape.DPC ceramics.Let's introduce how to process Teflon circuit board without falling or foaming

  Welding resistance machining(comparison of two machining processes)

  1.General process:plate brushing-static setting(15 minutes)-silk screen welding resistance-static setting(15 minutes)-pre drying-static setting(15 minutes)-silk screen-static setting(15 minutes)pre drying-static setting(15 minutes)-exposure-static setting(15 minutes)-Development-single stage curing 155℃/60min

  2.Product defect:insufficient static storage,and then curing for staged baking,resulting in bubbles at the junction of substrate and graphics.

  Improved processing flow:

  1)brush plate-static(15 minutes)-silk screen solder mask-parallel static(30-60 minutes)-pre drying-static(15 minutes)-silk screen-static(60 minutes)pre drying-static(15 minutes)-exposure-static(15 minutes)-Development-single stage curing(80℃/20min+90℃/20min+100℃/20min+120℃/20min+155℃/60min)

  2)long standing time,parallel standing,and post curing for staged baking,obviously the product is perfect.

  Improvement effect analysis:polytetrafluoroethylene fiberglass cloth is obviously rough.The speed should be strictly controlled in the process of silk screen printing.The slower the speed is,the less bubbles are.Then the thickness of the ink produced by silk screen printing is thinner,and the ink is covered evenly at the junction of the base material and the line,so that the diluent in the ink is easy to volatilize,which will not cause sharp shrinkage of the board when it is cured and baked at high temperature Make ink bubble.However,it is necessary to put the bottom copper plate of more than 1 oz horizontally after screen printing.Because of the high line,the ink can not flow and accumulate in the same direction,resulting in uneven foaming of the ink thickness.In the post curing fault,polytetrafluoroethylene(PTFE)plate is a special material,and the phenomenon of expansion and contraction is obviously larger than that of the general plate under high temperature.Therefore,it is necessary to cure the resistance welding ink gradually from low temperature to high temperature to avoid blistering of the resistance welding film.After 288℃/10s/3 thermal shock test,the bonding rate between the solder mask and the base material was verified,and no drop was found.

  Through the introduction of DPC ceramics,it can be known that long standing time,parallel standing,and post curing for sectional baking can make a non foaming and non dropping polytetrafluoroethylene circuit board.



DPC ceramics

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