Johnny SolidWorks
Hot Rolled
- Joined
- Apr 2, 2013
- Location
- Rochester
Looking for a sanity check, because I've broken a couple of endmills, and I'm apparently too stupid to understand why on my own.
Full disclosure: I'm just starting to use more carbide tooling in the mill (Haas VMC) but have never had issues like this with HSS/Cobalt tooling.
I'm using the endmill in the picture below: 1/2" bullnose, 3 flute, carbide, 1 5/8" flute length.
Material is 1" x 2.5" x 8" 1018 CRS bar stock clamped in soft-jaws for clearance to put a scallop (1 5/16" radius half hole) in at the centerpoint of one side. I keep an eye on it to clear chips, otherwise they like to build up in the pocket (i.e. I don't just walk away.)
Dataflute's recommendations are shown here:
I used the same speeds/feeds to square off both ends of the stock, and while it is alarmingly fast to a guy used to running HSS tooling gently, the chips looked good, no nasty harmonics or noises, and the cutter seemed perfectly happy.
I'm doing everything full depth, bottom of the cutter .05" below the bottom of the stock. 2D adaptive clearing operation via HSMWorks. 325 SFM, .0035 IPT, .25 X Diameter Optimal Load (Diameter times .25, not .25") [Edit]
Rapids to scallop, cutter starts to engage and bang - handful of scrap for the (rapidly accumulating) carbide bucket.
Go back to Dataflute, take speed adjustment to minimum: recommends 200 SFM, but chip load and radial depth of cut recommendations stay the same. Ok, lets give her a shot.
Well, now I'm 2 carbide endmills down.
Should I just dial this all the way back to HSS speeds and feeds and work my way up? I feel like I should be able to push way, way harder than that without issue. What stupid, idiotic, obvious mistake am I making? Do I have too much cutter engagement for their recommendations? Is there a rule of thumb for when you have 2xD cutter engagement for reduction to speeds/feeds? I really don't think it's my setup, but disabuse me of that notion if I'm wrong. I just don't know how I could make that much more rigid.
Thanks All
Full disclosure: I'm just starting to use more carbide tooling in the mill (Haas VMC) but have never had issues like this with HSS/Cobalt tooling.
I'm using the endmill in the picture below: 1/2" bullnose, 3 flute, carbide, 1 5/8" flute length.
Material is 1" x 2.5" x 8" 1018 CRS bar stock clamped in soft-jaws for clearance to put a scallop (1 5/16" radius half hole) in at the centerpoint of one side. I keep an eye on it to clear chips, otherwise they like to build up in the pocket (i.e. I don't just walk away.)
Dataflute's recommendations are shown here:
I used the same speeds/feeds to square off both ends of the stock, and while it is alarmingly fast to a guy used to running HSS tooling gently, the chips looked good, no nasty harmonics or noises, and the cutter seemed perfectly happy.
I'm doing everything full depth, bottom of the cutter .05" below the bottom of the stock. 2D adaptive clearing operation via HSMWorks. 325 SFM, .0035 IPT, .25 X Diameter Optimal Load (Diameter times .25, not .25") [Edit]
Rapids to scallop, cutter starts to engage and bang - handful of scrap for the (rapidly accumulating) carbide bucket.
Go back to Dataflute, take speed adjustment to minimum: recommends 200 SFM, but chip load and radial depth of cut recommendations stay the same. Ok, lets give her a shot.
Well, now I'm 2 carbide endmills down.
Should I just dial this all the way back to HSS speeds and feeds and work my way up? I feel like I should be able to push way, way harder than that without issue. What stupid, idiotic, obvious mistake am I making? Do I have too much cutter engagement for their recommendations? Is there a rule of thumb for when you have 2xD cutter engagement for reduction to speeds/feeds? I really don't think it's my setup, but disabuse me of that notion if I'm wrong. I just don't know how I could make that much more rigid.
Thanks All
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