Today we went to a machine shop currently running a production part on a 2013 Haas VF-3 machine.
The goal was to observe and record the cycle time machining the part. In addition to the cycle time, we wanted to check the actual smoothness of motion during the 3D surfacing. Typically, XYZ back-and-forth motion with higher feed rates causes “banging” when the direction reverses.
The test program was a large 3D surfacing program cutting wood. The feed rates varied between 200 and 600 IPM with a spindle speed of 15k RPM.
The focus of the visit was on servo performance, not so much block processing speed.
By its nature, every control’s cycle time is characteristically limited by two things: Servo Performance and Block Processing Speed.
On the VF-3, what we observed wasn’t so much a Block Processing Speed limitation as much as a Servo Performance limitation. At first glance, the VF-3 seemed pretty good; however, that was because most of the direction reversals were off the part. Using an indicator, we measured overshoot and undershoot as the feed rate increased. Had the part been a cavity, there would have been obvious overcuts.
After we finished our observations, we scheduled a time to demo their program on a Fadal 4020 with a NXGEN control.
More information to come!