When purchasing CNC wire cutting machine tools, three aspects can be considered: first, whether the machine body can meet its own processing requirements, and how about the quality of the machine. The second is the numerical control system. There are many kinds of numerical control systems, and selecting the appropriate system is the key to purchasing numerical control machine tools. The drive unit is also the key to machine tool control. Different drive units can achieve different machining accuracy. When selecting the drive unit, select the appropriate drive unit according to the accuracy requirements of the workpiece being processed.
The following analysis is made from three aspects: machine tool body, numerical control system and drive unit:
1. Selection of machine tool body
First of all, the machine tool structure design should be well matched with the size and weight of the workpiece. Full support machining center structure is adopted for medium and large load worktable. Only in this way can the design have sufficient bearing capacity, stiffness, accuracy, vibration resistance and accuracy retention. Secondly, the mechanical transmission of the feed system should use ball screw, which is superior to triangular and trapezoidal screw, and the diameter of the screw should be as large as possible to increase rigidity.
The third is the guide rail. The motion guide rail of the workbench is the key to ensure the motion accuracy of the workbench. Users should pay high attention to it when selecting the model. First, observe the size of the cross section of the guide rail. Under the same conditions, the thicker the guide rail is, the better the rigidity is. The less deformation is likely to occur during processing, so as to ensure the accuracy and durability of the machine tool in long-term operation.
2. Selection of CNC system
The CNC system is a part of the CNC machine tool; Brain”, Calculate and process the control information of the machine tool. According to the principle of numerical control system, it can be divided into economic numerical control system and standard numerical control system.
2.1 Economical CNC system
Economical CNC system generally refers to open-loop CNC system from the perspective of control method. Open loop numerical control system refers to that the numerical control system itself does not have a position detection device, and the numerical control system sends a certain number and frequency of command pulses, and the drive unit locates the machine tool.
When the open-loop system is affected by external factors, the machine tool does not act or does not act in place, but when the system has reached the designated position, the machining accuracy of the machine tool will be greatly reduced.
However, due to its simple structure, rapid response, stable and reliable operation, convenient debugging and maintenance, and very low price, the improvement of performance is limited by the mutual restriction of torque frequency characteristics and accuracy, feed speed and torque of stepping motor. Therefore, the economical CNC system is currently used for CNC fast wire cutting and some economical medium wire cutting machines with low speed and accuracy requirements, and is also widely used in the NC transformation of ordinary fast wire cutting machines.
