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--- pcbetching [2022-01-16 11:43] – [Safety] jtdburton
+++ pcbetching [2022-01-19 20:56] – [Exposure] jtdburton
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 Use your image editing software of choice to prepare your cut file for lasering. It needs to be a vector with all shapes as outlines and no fill, and it needs to be mirrored either in your image editor or once you import it into the LaserCut software.
-Place your workpiece in the laser cutter copper side DOWN. Cut settings may need some experimenting to get right. The aim is to cut all the way through the substrate without hitting the copper hard enough to cause lots of sparks. My best results have come from using the big laser with speed 35, power 60, corner power 50 on 1.5mm board.
+Place your workpiece in the laser cutter copper side DOWN. Cut settings may need some experimenting to get right. The aim is to cut all the way through the substrate without hitting the copper hard enough to cause lots of sparks. My best results have come from using the big laser with speed 25, power 60, corner power 50 on 1.5mm board.
 Run the cuts. Give it a couple of minutes before you open the lid, vapourised FR1/2 isn't as bad as FR4 but it's still unpleasant.
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-===== Exposure ====
+===== Exposure =====
-Grab the laminator, some sellotape, and a pair of scissors from G1 before you start with this section.
 Currently (as of January 2022) the lab has NEGATIVE photoresist, which means the copper will be removed from the areas of your board NOT exposed to UV light.
-In the past the recommendation has been to use transparencies run off the laser printer for UV masking. This does not actually work very well because the "black" areas do not come out fully opaque. Tracing paper may work - as of this writing we don't have any. One good way to produce a UV mask in the absence of proper printables is to laser-cut your trace pattern into a scrap bit of very thin plywood or black acrylic.
+The best option for creating your UV mask is to print it onto some heavy tracing paper on the laser printer in G1. You may need to print and overlay two copies.
+{{:20220118_211802.jpg?400|}}
+You can also cut your trace pattern into a scrap bit of very thin plywood or black acrylic.
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+Either way, once you have your mask ready, grab the laminator, some sellotape, and a pair of scissors from G1.
 Cut a piece slightly larger than your board from the roll of photoresist film kept wrapped in a black bag in the cabinet in G14. PUT THE ROLL BACK IN THE BAG - it's UV sensitive.