The Necessity and Feasibility of Maintenance and Reformation of CNC Machine Tools

my country has been using cnc machine tools on a large scale since the early 1980s. There are many factors that require maintenance and CNC upgrading of existing machine tools:

1. In many industries, these numerical control equipment are in key jobs. Some machine tools are running for a long time or even overloaded. At the same time, they lack serious repair and maintenance, causing serious machine tool wear and loss of precision;

2. Due to changes in the user and product structure, or due to insufficient technical strength, it has been idle for a long time, and some cnc machine tools are found to be unusable when they need to be used;

3. Due to the needs of new product manufacturing, the performance of the original CNC machine tools can no longer meet the requirements of use, and it is urgent to update and upgrade; at the same time, due to the rapid development of computer technology, the product update of CNC systems and drive systems is speeding up, and CNC systems need to be updated.

This is a large stock of equipment assets, repaired to become wealth. As long as the main technical difficulties are identified and the key technical problems are solved, the largest stock of assets can be activated with the smallest investment, and the largest economic and social benefits can be achieved. Especially for the imported CNC machine tools, hundreds of thousands to tens of millions of dollars have been spent. If the failure cannot be repaired and eliminated in time, it will cause greater economic losses. Compared with the purchase of new machine tools, the maintenance and upgrading of CNC machine tools can achieve the same use effect by only spending less than 30% of the cost of purchasing the same new machine tool. Therefore, the CNC repair and reconstruction of machine tools has many advantages.

The goal of maintenance and transformation of CNC machine tools is mainly to diagnose and restore the faulty parts of the machine tool; it is also possible to add a numerical control system to an ordinary machine tool and transform it into an NC machine tool or CNC machine tool; it can also carry out mechanical and electrical part transformation to improve The accuracy, efficiency or degree of automation of the machine tool; technical update or technological innovation can also be carried out on the basis of the original performance, to improve the level and efficiency of the equipment in a timely manner, improve the quality and grade of the equipment, and transform the old machine tool into a machine tool of today’s level.

Technical feasibility analysis and economic feasibility analysis should be carried out in the first place for the implementation of CNC machine tool maintenance and transformation. It is necessary to analyze the value of the transformation from the position and importance of the machine tool in the production of the unit; estimate from the input-output rate of the machine tool, whether the investment can be recovered quickly and whether it can quickly produce better benefits; after the machine tool is transformed Improve the accuracy of the machine tool, increase the function, whether it can improve the level of the unit’s products, or is conducive to the development of new products, so as to obtain additional benefits. At the same time, preparations for technical solutions must be carried out.

1. Mechanical and hydraulic system

Check the accuracy of the current machine tool, the condition of the mechanical transmission chain, the condition of the ball screw and the guide rail, and whether there are major failures, etc., to determine the machine tool maintenance and transformation plan (overhaul or project repair). If a non-CNC machine tool is to be changed to a CNC machine tool, the feasibility of mechanical modification must be considered first, the most important thing is the form of the guide rail and the installation of the ball screw, and then whether the transmission gap and transmission stiffness of the mechanical transmission mechanism meet the requirements of the CNC machine tool. Claim.

2. Electrical system

Select the CNC system according to the state of the machine tool and process requirements. On the basis of detailed understanding of the characteristics of the currently used CNC systems, the performance-price ratio and the functional requirements of the machine tool, choose a more suitable CNC system and determine whether to replace the drive system, so that it can meet all the functions of the machine tool. Request without raising the standard.

For the peripheral circuit, there are two options for transformation: “interface type transformation”, that is, the peripheral relay circuit is reserved, and only the NC and PLC are transformed. The new PLC does not participate in the control of the peripheral circuit, and only processes the command signals required by the NC. This scheme has a small amount of transformation design and debugging. The other is “complete transformation”. When the relay logic is more complicated, the failure rate is high, and the logic diagram is clear, the PLC of the new NC can be used to transform all the peripheral circuits, which simplifies the peripheral circuits and makes reasonable use of them. It has the control ability of PLC. This scheme can simplify the hardware circuit and improve reliability.