Our Fall 2015 Sine Plate Project

[ParisDakar]

We got a good bit of work done this week. We decided that it would be better to rough out all sides of the plates first before we do any finish facing. That is, machining off the welds, the backer plates, and torch cut surfaces first.

For this work we used a six flute 1" cobalt roughing mill (actually measures at 0.964) at a little over 400 rpm. Used a feed rate of 4" per minute for a chip thickness of .006". Took off 20 to 60 thou per pass.

For both trimming the ends and cutting the welds, we laid the plates down or stood them straight up so that we could use the power feed on the X-axis, eliminating the manual feed rate issues of last time.

Discovered that the mill appears to cut maybe a thousandth deeper on the left than on the right, in the 6" plate width. Occurred on 2 or 3 of the plate faces, the other 1 or 2 were not as apparent.

Should have been done first, but the mill should be leveled, and the head has to be trammed. The backlash in the lead screws needs to be adjusted, and the vise needs to be reset dead nuts on the table. None of this has ever been done, and I'm torn between involving students or not in these things. I How do you teach an appreciation of precision that can't be seen?

So we've got 2 plates ready to start machining to final dimensions.

http://wiki.team1640.com/index.php?title=Sine_Plate