Machinist Apprentice | Parabolic Mirror Part | Day 62

Very excited to get back to work after the long labor day weekend. 

Today I was working on a part for a parabolic mirror, which will be one small piece apart of a large, very powerful flashlight/laser. The issue I had last time with this piece is a small inner groove where the 1/16" endmill would leave a mark where it retracted out of the part. What would happen is the tool would dwell for a split second, then retract straight up; this was just long enough for the endmill to leave a circular mark on the surface finish (it was only visible, and when you run your finger across it, you can't feel any difference).

I was able to fix the surface finish issue by going into the linking tab in fusion360, where you set the lead in's and out's and programmed it to do a slow arc at a 15-degree angle upward as it fed out. I was able to try it out and got some pretty decent results; I am still able to see where the tool exited, but it's nothing I can't clean up with a little scotch bright. 

The roughing on this part did take longer than I would have liked (at about 55 minutes with a 1/4" tool), but even that made the machine sound like it was pushing pretty hard, even though I've pushed this particular endmill through much more and had excellent results. My guess is that since I am using the 4th axis, the stability isn't as great as the vice, and so vibrations play a much more significant part.