[Applied Science] wanted to make some metal parts with a lot of holes. A service provider charged high tooling costs, so he decided to create his own parts using photochemical machining. The process is a lot like creating PC boards, but, of course, there are some differences. You can see the video of the results, below.
Some of the parts could be made in different ways like water jet cutting or even stamping. However, some things — like custom screens — are only really feasible to do with a chemical process like this.
Like PC board etching, you deposit resist on the metal and then use a reactant to eat away the parts you don’t want. Cleaning the metal is essential before putting on the resist. Using water, it is easy to tell if the metal is clean.
There were a few interesting wrinkles to the process. For one thing, the parts are etched in a mesh bag so that as the parts come off the base plate, they stay put in the bag. Some of the equipment is borrowed. For example, a sous vide cooker holds water at a fixed temperature. A cheap laminator adds dry resist film to the metal with a simple modification.
We imagine that any of the normal ways you do PC boards like direct toner transfer would work to set up the resist. However, in this case, [Applied Science] uses tools means for screen printing masks to produce photomasks. The etching tank used was especially impressive and looked like it had the potential to make a huge mess.
The results were tainted a bit because of a problem with the etcher, but they still looked pretty good. If you are already set up to to do PC boards, this probably isn’t a big stretch.
We’ve seen a lot of different ways to approach chemical machining although, more commonly, with electicity.