That's fairly aggressive I would think. Looks like it chattered a lot.
I am attempting to bore 65mm holes in 4" aluminum bar. A photo of the result is attached. It's ugly! I have experimented with alot of variables but still get this tearing of the metal instead of a clean cut.
Machine: Tormach PCNC 1100 series 3
Controller: PathPilot
Tool: 1/2" Glanze through-coolant boring bar (steel)
Insert: CCMT, tried one for steel and one for aluminum with the same result
Surface speed: 150-500 meters/min
Feed rate: 550-800 mm/min
depth of cut: 0.25-0.5mm
Insert is parallel to X-axis and centered in the bore
All the other cuts on the machine are working great. Facing, turning, parting are all no problem. What am I doing wrong with boring?
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That's fairly aggressive I would think. Looks like it chattered a lot.
Are you using the shortest boring bar possible? Just long enough to reach bottom of bore.
The hole is only 3/4" deep, The boring bar stickout is about 1.25" right now. If I eliminate the through-coolant, I could choke is up right next to 3/4".
On my manual lathe, I can run a lot more stickout than that with no chatter. And that's with a cheaper, thinner boring bar.
Try again at 3-500 rpm 50-80mm per minute. I've not used the tormach but when I'm having trouble boring that range almost always works well.
Ben
Thanks for all the help and suggestions here. I finally fixed the problem by a combination of choking up on the boring bar as far as possible, re-routing the coolant line to maintain through-coolant, .25mm depth of cut, 157 m/min surface speed, and 550 mm/min feed rate.