After all these years I have been building molds, both for plastics and for investment casting, I still learn new things. I am building a mold for one of my best customers and I needed to make an EDM electrode to burn the details. The part is a hexagon shaped part with inside details cored out with sharp corners. I hadn't considered that the part required sharp corners on the inside of the electrode. Now I was in a pickle, I don't have the time to wire an insert to create the sharp inside corners, so how do I do it with the ram EDM?
Well a little bit of thinking and I came up with a way to create those sharp corners and still create the electrode quickly. I used an endmill to mill the electrode, and where I had to make sharp corners, I moved the cutter past the corner on three sides, and past the corner in the opposite direction on the other three sides, so that if I rotated the electrode 180 degrees, the corner would be burned sharp from the other side. It worked like magic, the corners are sharp and I saved myself a bunch of work. The best part is I don't have to worry about an insert ever flashing or showing a witness line.
In this business every mold is different and every job is a learning experience.
Jim