Matt@RFR
Titanium
- Joined
- May 26, 2004
- Location
- Paradise, Ca
I'm working on half-done 304 parts for another machine shop due to them having some machinery problems at the moment. All I have to do on these is rough and finish a profile and chamfer.
The tool is an MA Ford 3/8" 4 flute with Altima coating, 7/8" LOC, .015" radius corners, hanging about 1.3" out of an ER-25 collet. Runout is .0006". The big extension is necessary to clear fixture clamp bolts. The 3/8" diameter is necessary because the fixture won't hold up to a 1/2" or larger endmill at any reasonable chip load.
The parts are .360" thick and I'm going around them at about .130" step downs, anywhere between 5% stepover and full slot due to the shape of the parts. 220 SFM and .002" IPT. Pretty much in the middle of MA Ford's recommendation. LOTS of coolant right at the cut.
The parts are made from 304 sheared flat bar, and I have some concerns whether the material is already work hardened from shearing. Any comments on that?
The parts have been faced on four sides. I'm wondering if the other shop work hardened these while facing, but wouldn't they have had tooling issues from that?
The cut sounds good, spindle load is very consistent right up until the endmill suddenly gets all the corners knocked off of it. So how would you guys go about cutting possibly work hardened 304? I'm not sure that's the problem, but it's definetely an unknown factor. 180 SFM? Lower? The last endmill ran 4 parts...roughly 96" of cutting at the above step downs. No chatter is evident.
I have 55 parts to go and 3 roughing endmills left. The parts need to ship on Monday...
The tool is an MA Ford 3/8" 4 flute with Altima coating, 7/8" LOC, .015" radius corners, hanging about 1.3" out of an ER-25 collet. Runout is .0006". The big extension is necessary to clear fixture clamp bolts. The 3/8" diameter is necessary because the fixture won't hold up to a 1/2" or larger endmill at any reasonable chip load.
The parts are .360" thick and I'm going around them at about .130" step downs, anywhere between 5% stepover and full slot due to the shape of the parts. 220 SFM and .002" IPT. Pretty much in the middle of MA Ford's recommendation. LOTS of coolant right at the cut.
The parts are made from 304 sheared flat bar, and I have some concerns whether the material is already work hardened from shearing. Any comments on that?
The parts have been faced on four sides. I'm wondering if the other shop work hardened these while facing, but wouldn't they have had tooling issues from that?
The cut sounds good, spindle load is very consistent right up until the endmill suddenly gets all the corners knocked off of it. So how would you guys go about cutting possibly work hardened 304? I'm not sure that's the problem, but it's definetely an unknown factor. 180 SFM? Lower? The last endmill ran 4 parts...roughly 96" of cutting at the above step downs. No chatter is evident.
I have 55 parts to go and 3 roughing endmills left. The parts need to ship on Monday...