WORKING LOAD SIMULATION ON THE CNC MACHINE

Abstract

The CNC machining is performed according to a pre-prepared control program (CP). The CP records all the necessary actions of the machine to obtain the part by metalworking in accordance with the requirements of the drawing according to the developed technology. Precise formation of surface dimensions during machining is performed by a cutting tool, the trajectory of which is recorded in the CP.
 In real conditions, during CNC machining, errors may occur, the size and direction of which depend on many factors, which are difficult to anticipate. For example, the occurrence of dimensional variations is affected by the real technical condition and setting of the technological system of the CNC machine, elastic deformations of system elements from cutting forces, thermal deformations, etc. The value and direction of elastic deformations of the machine are influenced by the cutting forces, size and direction of which depend on the processing modes, the shape and size of the workpiece, the material of the tool cutting part and the material of detail.
 There are known methods of accounting for the expected processing errors in the calculation of trajectories of tools in the presence of data on the flexibility of the technological system of CNC machine. Such data can be obtained as a result of studies of the flexibility of machine tool elements when simulating workloads.
 To perform tests to determine the elastic deformations of a technological system in production conditions, a device has been developed to simulate working loads in a wide range and various places in the working area of ​​CNC machine. The device contains a loaded shaft with replaceable bushings on which annular contact grooves are made. The configuration of the device is assembled taking into account the design features of the CNC machine and the assigned research tasks.
 According to the control program or manual control, simulation forces are created by a load device with poppet springs installed in the cutter holder of the machine. Strain value is measured by linear displacement meter. The obtained data allow you to determine the stiffness of the machine elements and give a forecast for the amount of expected dimensional errors during processing.