Experimental stability boundary for a three-flute 20 mm indexable end mill in slot machining of aluminium 7075-T651
Chatter test Results along with impact test results on the tool mounted on the spindle of the DMC160 machine tool, in the stationary condition. The chatter tests spans 7500-9500 rev/min and depth of cuts of 0.25 to 1.2 mm.
Steps to reproduce
Exact reproduction could be challenging since dynamic properties of machine tool components and their damping properties are affected by wear and tear, temperature, surface details of connected parts etc. However, the following steps were taken to arrive at these results: 1. a 1000x240 x 25 mm 7075 T651 plate was mounted on DMC160 FD machine tool's bed. 2. A Tool Assembly with R217.69-2020.0-09-3AN, with 3 XOMX090308TR-ME06, F40 M inserts, was mounted with 95 mm stick-out on a C8-MEGA 20D-75 holder, on machine tool’s spindle. 3. Impact tests were performed by Dytran 5800B4 hammer and a Dytran 3225F1 accelerometer. 4. The machine tool was programmed to first clean up the surface of the parts with a slot cutting at a 2 mm depth and then at depths from 0.25 to 1.2 mm. Each depth was cut at spindle speeds ranging from 7500 to 9500 rev/min with 100 rev/min intervals. Cutting was interrupted at the end of each cutting with the specific spindle speed by moving the tool away from the workpiece and pausing feed movements. 5. The sound and acceleration on spindle housing were recorded during machining. The distinct sound and acceleration signals were analyzed using FFT. 6. The amplitude of vibration signals along with marks on the surface of the workpiece was used to separate stable and unstable conditions. At each spindle speed, the lowest depth of cut showing chatter (unstable cutting) was considered a chatter boundary.