How to choose the CNC processing center

(1) the stiffness of the machining center
Because the rigidity of the machining center will directly affect the production efficiency and the machining precision of the machine tool, the machining speed of the machining center is much higher than that of the ordinary machine tool, and the motor power is higher than the common machine tool with the same specification, so the stiffness of its structure design is far higher than that of the ordinary machine tool. Orders can be checked according to the technological requirements, allowable torque, power, axial force and maximum feed force, according to the manufacturer’s numerical value. In order to obtain the high rigidity of machine tools, it is often not limited to the size of the parts, but the machine tool with 1 or 2 sizes relative to the size of the parts is selected.
(2) the machining accuracy of the machining center
Machining accuracy will directly affect the quality of products. Many people will directly affect buyers’ decisions when they question the accuracy of machine tools. Attention should be paid to the two different concepts of machining accuracy and machine tool accuracy. It is wrong to regard the location accuracy of the manufacturer’s sample or the product certificate as the machining accuracy of the machine tool. The precision of the position of the sample or the certificate is the precision of the machine tool itself, and the machining precision is the sum of the errors produced by various factors of the whole process system including the error allowed by the machine tool itself. In the selection, reference can be made to the evaluation method of process capability KP as the basis of accuracy selection. Generally speaking, the calculation result should be greater than 1.33.
(3) selection of CNC system in machining center
CNC system is the core of the machining center operation. CNC functions are divided into basic functions and selection functions. The basic function is provided, and the choice function is only provided when the user chooses these functions. The function of the CNC system must be selected according to the performance requirements of the machine tool. In order to order the function, we should not only set the functions needed, but also avoid the loss of the use rate, and also pay attention to the relevance between the functions. In the numerical control system that can be selected, the performance is very different. We should choose according to needs and not unilaterally pursue high targets, so as not to cause waste. When selecting a number of machine tools, it is possible to use the same manufacturer’s numerical control system as much as possible, so that operation, programming and maintenance can be more convenient.
(4) the number of coordinate axes and the number of linkage axes
The number of coordinate axes and the number of linkage axes should meet the requirements of typical workpiece processing. The number of coordinate axes is also one of the marks of machine tool grade. Under normal circumstances, with the manufacturer, the same specifications, the same accuracy of machine tools, add a standard axis, the cost will increase by about 35%. Although increasing the number of axes can enhance the function of machine tools, we must pay attention to the technological requirements and capital balance.
(5) the automatic knife exchange device and the capacity of the knife library
The selection of automatic tool changer mainly considers the time and reliability of tool changer. Short switching time can improve the productivity, but the changing of the knife time is short, the common tool changing device has complex structure, high failure rate and high cost. Too much emphasis on changing the knife time will increase the cost and increase the failure rate. According to statistics, about 50% of the faults in the machining center are related to the automatic knife exchange device. Therefore, the automatic tool changing device with high reliability is chosen to reduce the failure rate and the cost of the whole machine, on the premise of meeting the requirements. The working quality and tool magazine capacity of automatic tool changer will directly affect the performance and quality of the machining center. The capacity of tool magazine is to meet the needs of a complex machining part for cutting tools.