Finally, getting the last of this Delrin project finished up and got the final pieces' first operation!
This last part really threw me for a loop, and when picking up the initial stock for it, I mismeasured the size of it, leading to a rushed order that only arrived this morning. The piece has very minimal features and could almost be done in a single operation; however, the tricky part about it was its size.
This piece is fairly similar in shape to the skateboard truck assembly I made a few weeks ago, with a flat plate, then a large block in the center. Because of the large block in the middle, the machine would take quite a bit of time removing the material from the sides. I was able to shave a bit of time off the complete run by manually cutting out the corner pockets in the vice before putting it back on the fixture plate to finish up.
Delrin is an interesting material to say the least, its got hard solid chips when cut with a sharp endmill, but with dull ones, it gums up quite bad. It also can fluxuate and move depending the temperature, which really confused me when I found my parts a thou or two under after pulling them out of the machine, then nearly spot on a few minutes later.
The maximum flute length we have is barely 1," and the part is approx 1.5"; this requires multiple stepdowns, which leaves marks on the finished surface from the tool depths, as well as chatter from the endmill jumping around. Unfortunately, there wasn't any way of fixing this on the machine, and would have to be cleaned up by hand with a razor blade, taking very light passes until the surface was smooth.
Once the first operation is complete with these last two parts, I can hold it in a vice, deck the top, and chamfer the edges before shipping everything out!
I also was able to finish up the final drilling and pocketing operations for the other parts, using the jigplate I setup last week (see previous post). Had no issues setting it all up and ran through each part smoothly!