Author Topic: Precision and Rigid CNC milling machine  (Read 1354 times)

Offline jadge

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Re: Precision and Rigid CNC milling machine
« Reply #15 on: November 27, 2021, 09:08:37 PM »
....what do you think about the TORMACH 770M?

It's a hobby machine. I have a Tormach PCNC1100 Series 2. It's a good machine and I am pleased with mine. I have been able to compare parts made on my Tormach and then on an industrial CNC mill. The industrial mill was more accurate; ~0.03mm versus ~0.02mm. But the industrial machine was much faster on cycle time. As an aside the professionals made a real hash of making the parts as they declined to listen to my advice, so much so that we refused to pay. I would say that Tormach are good machines, if a little expensive now for what they are. But they are not intended as production machines. I have made money with mine, but that's because the machining is an adjunct to the design work. I'm not trying to make money purely by machining.

The Tormach servos are only closed loop in the sense of controlling the position of the motor. The closed loop does not include control of the table position. That is still dependent upon the accuracy of the ballscrew and backlash. The closed loop servo simply means that you do not miss steps. In many hundreds of hours of machining I have never knowingly missed a step with the open loop steppers. And I run my machine hard, to the point of stalling the spindle.