Anybody Thread Whirl on their Swiss machine? I have a Star 32 Lathe and want to thread whirl some taps & screws. I have an attachment with the 3 insert cassette, how does that compare with 6 inserts? Is it worth upgrading to the 6 insert holder? Where do ya get custom formed inserts (for things like bone screws)? Any tips, tricks, tool suppliers, or general info would greatly be appreciated. Thanks
The concept is similar to the difference of a 2 flute end mill and a 4 flute. There are 3 basic possible improvements:
1. Productivity - The chip load stays the same per tooth, which means productivity increases as a result of faster cutting velocity (C-axis rpm) and a reduce whirling cycle.
2. Finish - The velocity (c-axis feed) stays the same which means the chip load per tooth is reduced.
3. Improved Finish and Productivity - The chip load per tooth is reduced slightly but the overal cutting velocity has increased.
I have done many bone screws both with the Schwanog 6 inserts and Utilis 12 inserts. In both cases the results were better finish and prducitvity. I have found the Utilis system however to have more accurate tip to tip repeatability, this actually had a result on better tool life, productivity and finish becuase each insert had a more even bite during the cut and the machine ran about 25% longer before an insert change was necesary.
The most critical thing with more inserts is to have accuartely aimed high-pressure coolant for chip evacutation, it must be hitting the inserts. Coolant hitting near the inserts is not acceptible becuase the volume of chips being removed is 2 - 4 times greater becuase of the faster cutting time; the coolant must be focused on the inserts or the chips will not evacuate properly.