Because CNC machining center is far more expensive than the general machine tool, so it is subject to more constraints, so whether the machine tool selection is reasonable or not is more important. Correct type selection is the key to make good use of the machining center and bring the machining center into full play. When purchasing a machining center, it is particularly important to carefully inquire about these five key points:
1 rigidity of machining center
Because the stiffness of CNC machining center will directly affect the production efficiency and the machining accuracy of machine tools, the machining speed of CNC machining center is much higher than that of general machine tools, and the motor power is also higher than that of general machine tools of the same standard, so the stiffness of its structure design is far higher than that of general machine tools. The order, the awesome torque, power, axial force and feed force can be checked according to the manufacturer’s supply value. In order to obtain the high rigidity of machine tools, it is often not limited to the size of parts, but choose the machine tools which are 1 to 2 standards larger than the size of parts.
2 machining accuracy of machining center
Machining accuracy will directly affect the quality of products. When many people question the accuracy of machine tools, it will directly affect the decision of buyers. Attention should be paid to that machining accuracy and machine tool accuracy are two different concepts. It is wrong to regard the position accuracy on the manufacturer’s sample or product certificate as the machining accuracy of the machine tool. The position accuracy indicated on the sample or certificate is the accuracy of the machine tool itself, and the machining accuracy is the sum of errors generated by various elements of the whole process system, including the errors allowed by the machine tool itself. In the selection, we can refer to the identification method of process ability KP as the basis of precision selection. Generally speaking, the calculation result should be greater than 1.33.
3.The choice of NC system of machining center
Numerical control system is the central brain of CNC machining center operation. The function of numerical control is divided into fundamental function and selective function. The basic functions must be supplied, and the selected functions can only be supplied by the manufacturer after the user has selected these functions. The functions of the CNC system must be selected according to the functional requirements of the machine tool. When ordering, the required functions should be fully ordered and not lost. At the same time, it is necessary to pay attention to the correlation between the functions. In the choice of CNC system, the function is very different. We should choose according to the needs, not pursue high goals unilaterally, to avoid wasting. When selecting multiple machine tools, the CNC system of the same manufacturer should be selected as far as possible to make the operation, programming and repair easier.
4. Coordinate axis number and linkage axis number
The number of coordinate axes and linkage axes should meet the requirements of typical workpiece processing, and the number of coordinate axes is also one of the symbols of machine tool level. In general, for the machine tools of the same manufacturer, standard and equal precision, the cost will increase by about 35% if a standard coordinate axis is added. Although increasing the number of shafts can enhance the function of the machine tool, it is still necessary to pay attention to the process requirements and the balance of funds.
5 automatic tool changer and magazine capacity
The time and reliability of tool changing should be considered in the selection of automatic tool changing equipment. Short tool change time can improve the production rate, but the tool change time is short. Generally, the structure of tool change equipment is messy, the failure rate is high, and the cost is high. Overemphasizing the tool change time will greatly advance the cost and increase the failure rate. According to statistics, about 50% of CNC machining center failures are related to automatic tool changing equipment. Therefore, on the premise of meeting the application requirements, automatic tool changing equipment with high reliability should be selected as far as possible to reduce the failure rate and machine cost. The working quality of automatic tool change and the capacity of tool magazine will directly affect the function and quality of machining center. The capacity of tool magazine is based on the requirement of tool for a disorderly part.
Post time: Apr-12-2021