From 3e9adf2407b1c017682482c85b23636b9c4e0807 Mon Sep 17 00:00:00 2001 From: Jeff Moe Date: Sat, 21 Dec 2019 19:00:08 -0700 Subject: [PATCH] stencil paste notes --- HOWTO/laser-solder-paste-stencil-inkscape.md | 53 ++++++++++++++++++++ 1 file changed, 53 insertions(+) diff --git a/HOWTO/laser-solder-paste-stencil-inkscape.md b/HOWTO/laser-solder-paste-stencil-inkscape.md index 3077f57..624fbaf 100644 --- a/HOWTO/laser-solder-paste-stencil-inkscape.md +++ b/HOWTO/laser-solder-paste-stencil-inkscape.md @@ -315,3 +315,56 @@ far slower any way due to acceleration curves. * Engrave text on sheet saying what is what. * Find good gcode renderer. + +* Different transparency material. + +* Different transparency thickness. + +* Different lower layer (e.g. not paper). + +* Shrink pads in KiCAD before export. + +* Cut two pieces of mylar at same time. + +* Use 7 mil mylar. + +* Pololu's stencils: "Our stencils are made from 3-mil or 4-mil mylar with a low-power CO2 laser. The finest pitch we can handle is approximately 0.5 mm, and we strongly recommend that fine-pitch stencils be cut from the 3-mil mylar." + +* Use raster instead of vector processing of gcode. Using raster will cut/burn +away the whole section, instead of leaving dangling rectangles. This would +entail using `raster2gcode` instead of the J-Tech Inkscape plugin. + +* Use 2-4 mil Kapton film instead of mylar. Sample: McMaster P/N 2271K2. + +* Use paper instead of mylar. + +* "The secret to cutting mylar stencils is to stack two 7mil sheets together and cut them at the same time! Unlike Kapton stencils, the Mylar will melt if exposed to large amounts of heat." juanjchong.com + +* Use finer focus lens on LASER. + +* Blogger with good results used this mylar: +3M PP2200 mylar transparency film. Same blogger came up with aluminium +soda pop can stencil technique here: +https://lowpowerlab.com/2013/02/11/diy-smd-metal-stencils-the-definitive-tutorial/ + +* Post-processing, scrape off melted protrusions with razor blade. + +* Hackaday comments: +"Covering both sides of the Mylar with masking tape and getting the power/speed right means I can get perfectly usable stencils." +"I just use thin cardboard. then spray it with clear varnish. +No melting there." + +# References +Various sources of info. + +* https://code.forksand.com/forksand/pcba + +* https://code.forksand.com/forksand/marlin-lulzbot-laser + +* https://jtechphotonics.com/?p=473 + +* https://jtechphotonics.com/Downloads/Inkscape/JTP_Laser_Tool_V2_2%20-%20inkscape%209_2%20version.zip + +* https://hackaday.com/2014/06/27/how-to-laser-cut-mylar-solder-stencils/ + +* https://web.archive.org/web/20190726174104/http://www.juanjchong.com/2014/cutting-mylar-solder-stencils-from-expresspcb-and-eaglecad-files/