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laserinfo:pcb_stencils [2009/05/06 20:10] ladyada |
laserinfo:pcb_stencils [2016/01/28 18:05] |
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- | ====== How to make PCB solder paste stencils ====== | ||
- | |||
- | You'll need: | ||
- | - A laser cutter | ||
- | - Kapton film, I like the 1 mil thick 1 ft square sheets from [[McMaster-Carr|http://www.mcmaster.com/#2271K2]] | ||
- | - Solder paste such as [[Kester No-Clean|http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=KE1507-ND]] | ||
- | |||
- | Software: | ||
- | - PCB layout software (well, thats how I do it) - this example will use EagleCAD | ||
- | - [[Pentalogix ViewMate Gerber viewer software|http://www.pentalogix.com/Download/download.html#item8]] | ||
- | - [[PDFCreator|http://sourceforge.net/project/showfiles.php?group_id=57796]] or some other free PDF printer | ||
- | |||
- | ===== Create Gerber files of cream layer ===== | ||
- | This is the PCB we'll be making a stencil for. It only has one chip but of course you can use a more complex layout | ||
- | |||
- | {{:laserinfo:eagle.gif|}} | ||
- | |||
- | Your PCB software should be able to create/export the Cream Layer (solder paste layer) in Gerber RS274x format. In Eagle you can make your own Job for this quite easily | ||
- | |||
- | {{:laserinfo:creamjob.gif|}} | ||
- | |||
- | Also export the Dimension layer (PCB outline) since that will help a lot in registration | ||
- | |||
- | ===== Import cream Gerber in ViewMate ===== | ||
- | |||
- | Start up ViewMate and File>Import>Gerber one of the Gerber files generated | ||
- | |||
- | {{:laserinfo:import.gif|}} | ||
- | |||
- | {{:laserinfo:swelled.gif|}} | ||
- | |||
- | You can zoom in using the Magnifying glass tool | ||
- | |||
- | {{:laserinfo:closeup.gif|}} | ||
- | |||
- | ===== Swell pads ===== | ||
- | |||
- | Next we will make minor adjustnents to shrink the pads a little | ||
- | |||
- | Select Setup>D Codes | ||
- | |||
- | {{:laserinfo:dcodes.gif|}} | ||
- | |||
- | Which will bring up a list of all the pads used. You will probably just want to select all of them | ||
- | |||
- | {{:laserinfo:pads.gif|}} | ||
- | |||
- | Then select Operations>Swell | ||
- | |||
- | {{:laserinfo:swelling.gif|}} | ||
- | |||
- | and input somewhere around -0.002 (2 mil) to shrink all the pads by 0.002 inches in each direction | ||
- | |||
- | {{:laserinfo:2mil.gif|}} | ||
- | |||
- | You'll now see that your pads are thinner. This prevents bridging since the laser is not perfectly precise and tends to 'go over' the boundaries by a few mils. | ||
- | |||
- | {{:laserinfo:postswell.gif|{{:laserinfo:postswell.gif|}}}} | ||