Research on the Design of Supporting Unit for CNC Engraving and Milling Machines Workbench

This paper presents a design of a supporting unit used for a workbench of CNC engraving and milling machines, which is driven by a linear motor and supported by a maglev linear guide. Traditional CNC engraving and milling machines make use of mechanical supporting technology, but this technology could not meet the new high-speed and high-precision requirements of machine tools. Electromagnetic suspension technology is used in this study, and realizes the target that the workbench has no contact with machine bed rails and feeds without friction. Based on the theory of Ampere circuit law and Newton's second law, we establish the electromagnetic suspension model, then derive and calculate the size, the coil current and the electromagnetic attraction of this type of supporting unit. The SolidWorks software is used to make their 3D models and the ANSYS software is used to make the magnetic circuit analysis and electromagnetic attraction calculations. The simulation results show that the magnetic lines mostly concentrate on the internal of electromagnets with little magnetic leakage, and the magnetic overlapping degree of supporting electromagnets and guiding electromagnets is very little. Therefore, the electromagnets can be analyzed and controlled respectively. The electromagnet attraction values obtained by finite element simulation are close to the theoretical values, and their relative errors are in a permissive range, so the electromagnetic design of the supporting unit is acceptable.