Motor Temperature Control Patent Improves Cnc Machine Tool Stability

Motor temperature control patent improves CNC machine tool stability

June 27, 2023
Anca’s new technique keeps motorized spindles at a constant temperature

CNC grinding machine and tooling manufacturer Anca was granted a U.S. patent for its motor temperature control (MTC) technique. It can maintain a machine tool’s motorized spindle at a constant temperature, which will improve accuracy and stability of the machine and reduce the time needed for the machine to reach working temperature.

Modern machine tools use motorized spindles where the driving motor is an integral part of the spindle. Dimensional errors in the spindle, which holds and drives a machine’s cutting tool, will reflect as errors in the final product, and the temperature of the spindle can affect the precision of machine tools.

Anca’s new patented technique can improve the stability of precision machine tools by maintaining a constant temperature. Changes in temperature of the machine tool can be caused by changes in ambient temperature, coolant temperature, run time, spindle rpm and spindle load.

Anca’s technique actively controls spindle temperature by varying the electrical losses in the motor element. Anca said special firmware in the spindle drive amplifier simultaneously maintains spindle motor speed and load.

MTC applications

A common practice in precision machining is to run the machine in a warmup cycle to bring all the elements of the machine to some level of thermal stability. Typically, this warmup cycle will take approximately half an hour. Anca said using MTC, this time can be reduced to around 5 minutes (Figure 1).

The accuracy of high-speed gear box components in the drivetrain of electric vehicles will impact lifetime, efficiency and nose of the electric vehicle. Anca manufactures a special machine, GCS, for grinding this class of tools. Skiving cutters are used to manufacture internal and external gears and determine accuracy (Figure 2). For this AAA class cutter, MTC is used to control the temperature of a dressing spindle, which creates a high accuracy profile on the grinding wheel. MTC also controls the main grinding spindle temperature for up to 12 hours of continuous grinding.