How to make etched metal parts. -All of the highest quality parts that I made went to the customer, but edge quality and photoresist adhesion is still a problem. -The photomask dark areas can be expanded, and then the part etched for a longer amount of time to make the edges more perpendicular to the surface. I forgot to mention this clever way to improve the etch aspect ratio called "etch factor" http://www.chemcut.net/wp-content/uploads/2015/03/Chemcut_Thoughts_on_Undercut.pdf -Dry film photoresist https://www.amazon.com/30cm%C3%975m-Portable-Photosensitive-Production-Photoresist/dp/B07MMVPY1Z/ -Photoresist processing datasheet https://www.dupont.com/content/dam/dupont/amer/us/en/products/ei-transformation/documents/DEC-Riston_GeneralProcessingGuide.pdf -Special ink and transparencies (films) for photomasks: https://filmdirectonline.com/ -Flip pins https://shop.evilmadscientist.com/productsmenu/853 -405nm lights: https://www.amazon.com/gp/customer-reviews/R2BR1XN80FQT9R/ -Epson printer with tank for custom ink: https://epson.com/For-Work/Printers/Inkjet/EcoTank-ET-M1170-Wireless-Monochrome-Supertank-Printer/p/C11CH44201 -Strange Parts did a great video on metal business cards: https://www.youtube.com/watch?v=83GDV0xsTTs -https://mymetalbusinesscard.com/product/stainless-steel-business-cards/ 100 cards for $250 could be the cheapest way to get custom mechanical parts: https://www.youtube.com/watch?v=bkZkaT_P0Ck Support Applied Science on Patreon https://www.patreon.com/AppliedScience