- Joined
- Nov 28, 2013
- Messages
- 196
I'll try to share enough of what I'm doing so that someone can pick off the mistakes.
The problem is that I'm losing depth of cut in pocketing operatoins in 6061-T6. For example, If I intend to cut a pocket to .750, I might instead get .662. I'm using a .375 4 flute endmill (I know it should be 2 flute for aluminum). I'm using misting coolant, running at 2800 rpm, Z-Axis travel 6 IPM and horizontal at 16 ipm. no chattering, but it isn't quiet either. I'm using 40% overlap and .020 depth of cut. I have not drilled a starter hole for the cuts nor am I ramping the cutter into the work. I suspect that this is where the problem might be. Or maybe the cutter is dull.
The stepper is Sherline's but I built the controller and it doesn't seem to have any problem with the other axes.
My plan is to buy some new cutters, try 45 dgree ramps into work, but keep same speed and feed and see if that cures the problem. I should add that I'm having similar problems drilling. the suggestion of the local guy who actually knows something was I wasn't advancing the drill fast enough and was either hardening the aluminum or dulling the bit or both. I've seen the calcculators for cooling up with feed rates depending on drill size and rpm and it'as true, I've been way timid. I do pecks at one drill diameter and the holes turn out nicely, but not as deep as specced.
Can any of you suggest anything else I should look at or identify where I'm screwing up.
thanks much,
john
The problem is that I'm losing depth of cut in pocketing operatoins in 6061-T6. For example, If I intend to cut a pocket to .750, I might instead get .662. I'm using a .375 4 flute endmill (I know it should be 2 flute for aluminum). I'm using misting coolant, running at 2800 rpm, Z-Axis travel 6 IPM and horizontal at 16 ipm. no chattering, but it isn't quiet either. I'm using 40% overlap and .020 depth of cut. I have not drilled a starter hole for the cuts nor am I ramping the cutter into the work. I suspect that this is where the problem might be. Or maybe the cutter is dull.
The stepper is Sherline's but I built the controller and it doesn't seem to have any problem with the other axes.
My plan is to buy some new cutters, try 45 dgree ramps into work, but keep same speed and feed and see if that cures the problem. I should add that I'm having similar problems drilling. the suggestion of the local guy who actually knows something was I wasn't advancing the drill fast enough and was either hardening the aluminum or dulling the bit or both. I've seen the calcculators for cooling up with feed rates depending on drill size and rpm and it'as true, I've been way timid. I do pecks at one drill diameter and the holes turn out nicely, but not as deep as specced.
Can any of you suggest anything else I should look at or identify where I'm screwing up.
thanks much,
john