We might have to pull back on this job. Took it to help a guy out, only 100 parts, loose tolerances, and figured we could find a way to make it work. Material was provided as unknown stainless but is certainly hardened. Bar is .875 and we have 4" stick out. Running a 3 jaw chuck in a 6" 2 axis lathe. We have a series of spindle liners stacked together because we don't have a .875 liner right now.
Machine has an obvious vibration and when manually running it, I didn't want to push it beyond 3k rpm but programmed the part to go to 4K. For quick testing, I tried everything from 500-3000, manually jogging in the material. WNMG 432 and 431 inserts.
The machine does NOT have any issues so we can exclude it as such. Without this material in it, it is quiet as a church mouse and holds tenths. The chuck however does have some wear and does not repeat very well and the bar has some runout. I will get an indicator on it but around .010" or more. We are obviously inducing enough runout that we get some vibration.
When I run the insert to the material, chatter is very bad. I did run a quick facing cut and it was like a mirror. Just unable to cut the OD at that much stickout. I ran the bar back to about 2" stickout and it cut just fine.
I am trying to figure out if getting the runout and vibration down can solve this or if we need to switch tactics. We don't have a collet chuck for that machine but want one. Only way I can see this working is have less stickout, cut the front features, then feed out more bar. It is an obvious swiss part. We also have a programmable center in that machine but that will just blow us out of the water with complexity and time for 100 parts.
Machine has an obvious vibration and when manually running it, I didn't want to push it beyond 3k rpm but programmed the part to go to 4K. For quick testing, I tried everything from 500-3000, manually jogging in the material. WNMG 432 and 431 inserts.
The machine does NOT have any issues so we can exclude it as such. Without this material in it, it is quiet as a church mouse and holds tenths. The chuck however does have some wear and does not repeat very well and the bar has some runout. I will get an indicator on it but around .010" or more. We are obviously inducing enough runout that we get some vibration.
When I run the insert to the material, chatter is very bad. I did run a quick facing cut and it was like a mirror. Just unable to cut the OD at that much stickout. I ran the bar back to about 2" stickout and it cut just fine.
I am trying to figure out if getting the runout and vibration down can solve this or if we need to switch tactics. We don't have a collet chuck for that machine but want one. Only way I can see this working is have less stickout, cut the front features, then feed out more bar. It is an obvious swiss part. We also have a programmable center in that machine but that will just blow us out of the water with complexity and time for 100 parts.
