Due to the high machining accuracy and high productivity of CNC machine tools, the proportion of applications in the manufacturing industry is increasing, which effectively guarantees product quality and output. Purchasing new CNC machine tools is a way to improve the CNC efficiency of the machine tools. It is also an important way to improve the CNC efficiency of the machine tools by carrying out the numerical control transformation of the old machine tools. The transformation of the CNC machine tool can reduce the cost of purchasing CNC machine tools and save the company money. In recent years, with the expansion of various types of domestic machine tool transformation needs, machine tool transformation has gradually formed an industry, most of which is the transformation of the old numerical control machine tools, and part of it is the transformation of ordinary machine tools. The problems that should be noticed in the process of NC transformation of the machine tool are described below for your reference.

First, the cost-effective analysis of the transformation and update of CNC machine tools

Prior to the transformation of old CNC machine tools, the market price of CNC machines with the same performance should be investigated. When comparing the prices of the two, supply time should also be considered. For small, inexpensive CNC machines and milling machines, it is recommended to upgrade and purchase new machines without retrofitting the old ones. Because the cost of the two is similar, less money is saved, and the machine tool rebuild time is about 2 months. For small CNC cars, milling machines, machine tool manufacturers generally have a spot. For large-scale, high-cost machine tools to carry out numerical control transformation is a better choice, not only can save more money, but also can shorten the acquisition time. For example, a table with a work surface size of 2000x1800mm, a three-axis linkage, and a horizontal machining center with 60 tools are compared as follows.

Second, the status of the machine to be reconstructed

Not all old machine tools are suitable for CNC retrofitting. A complete understanding of the machine tools that need to be modified is required.

The mechanical system of the machine tool should be properly mapped to make good judgments. Good mechanical performance is the basic condition for the successful transformation of the machine tool. Otherwise, the best CNC system can not play its due performance. Therefore, before machine tool CNC transformation, the machine tool should be tested for mechanical accuracy, and the found problems can be repaired during the implementation of the machine tool transformation. If the machine tool system has many problems, such as the old machine tool in the mechanical structure design, manufacturing defects, the machine tool CNC transformation will not have much significance.

The old machine tool electrical system is a key task in the transformation of machine tools due to constant aging of components. To understand the old machine tool control system model, the number of control axes, spindle, feed axis drive configuration, spindle motor power, feed shaft motor torque and so on.

Check whether the random technical data is complete and complete. The complete technical data can shorten the technical preparation time of the machine transformation. The electrical schematics, PLC programs, machine maintenance manuals, hydraulics, pneumatics, lubrication schematics, mechanical assembly drawings, etc., we must carefully study. Special attention should be paid to the fact that the contents provided by the technical materials may be incorrect and inconsistent with the actual machine tools. This is because some machine tool manufacturers provide general drawings of series models. The changes of the electrical hardware of individual machine tools are not marked on the electrical data. This requires us to check the actual machine tools and carefully check the mistakes.

Third, the determination of CNC transformation program

On the basis of surveying machine tools, according to the requirements of users, determine the overall machine tool transformation program.

1, the transformation of the CNC system The transformation of machine tools, the first is the transformation of the CNC system, according to the current control level of the machine tool, workpiece processing requirements, the company's funding conditions, select the appropriate low, medium and high-grade CNC system. When selecting the CNC system, it is necessary to consider the products of the mainstream manufacturers. For example, the foreign CNC system can select FANUC, Siemens system, etc. The domestic CNC system can select Huazhong and Kane systems. It should also be consistent with the selection of the CNC system of other CNC machine tools as far as possible for the machine tool user. The advantage of this is that it is convenient for maintenance personnel to maintain the machine tools on a daily basis; a more centralized CNC system can also facilitate the reduction of Spare Parts types.

When the numerical control system is selected, it is based on practical principles. There is no need to waste funds for pursuing higher grades.

2. Modification of Spindle Servo System The spindle control of old CNC machine tools generally uses a DC servo or AC analog servo drive system (usually a +/-10V analog signal). According to the use requirements, the original drive device and spindle motor may not be retained, and an AC digital servo drive system may be used instead of or in addition to the inverter control. It is also possible to retain the original drive system, such as a good AC analog servo drive system; the DC servo drive system can retain a good state of the DC motor, using a new DC servo control device instead of the old drive device.

3. The transformation scheme of the feed servo system is similar to that of the spindle servo system. According to the use requirements, the original drive device and the motor may not be retained, and an AC digital servo drive system may be used instead; the original drive system may also be retained, such as in good condition. AC analog servo drive system.

4. Modification program of closed-loop control detection device For the inductive synchronizer/feet of the old machine tool, it can be replaced by a circular grating and a grating rule. When selecting the type, note the consistency of the interface signal between the detection element and the system, square wave signal or voltage signal. . If the old current signal scale is retained, a current signal must be added to the voltage signal conversion device to match the new system because most new systems do not support current signals.