How to repair the most popular CNC machine tools

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As we all know, CNC machine tools are the crystallization of the integration of modern high-tech machinery, electricity, light and gas. They are electrically complex, with intersecting pipelines, and a variety of CNC systems. Products from the 1970s to the 1990s cannot be interchanged. The fault phenomena are also strange and different, especially large and Heavy CNC machine tools, which are expensive, about several million dollars each The installation and adjustment time is long (several months to more than 1 year). There are thousands of components in large-scale CNC machine tools. If one of them fails, it will cause abnormal phenomena of the machine tools, as well as the connection of wires and pipes. A little negligence will cause problems. In addition, large-scale and heavy-duty CNC machine tools are huge in volume, and they are used without constant temperature workshop, so the impact of the environment is easy to cause failures. Therefore, the problem of "difficult maintenance" of CNC machine tools is put in front of us

our country has introduced and manufactured so many CNC machine tools. How can we quickly find out the faults and hidden dangers and eliminate them in time? How can we repair these expensive equipment? I think first of all, we should have a high heart and the spirit of not afraid of difficulties; Second, we should strive to master numerical control technology. In connection with my more than ten years of practice in repairing numerical control machine tools, I think we should see more, ask more, remember more, think more and practice more (more than five), and gradually improve our technical level and maintenance ability, so as to adapt to various complex situations, solve difficult problems and repair numerical control machine tools

first, we should read more

1. We should read more numerical control materials

we should read more, and we should understand the characteristics and functions of various numerical control systems and PLC programmable controllers; To understand the alarm and troubleshooting methods of CNC system; To understand the parameter setting of NC and PLC machine tools, the meaning of oil delivery valve should be cleaned; Understand the programming language of PLC; To understand the method of NC programming; Understand the operation of the control panel and the contents of each menu; To understand the performance of the spindle and the cutter motor and the characteristics of the driver, there are often a lot of NC data. What do you think? I think the main thing is to highlight the key points, understand the context, and generally output these eight key points is to understand the basic composition and structure of the CNC system and master the block diagram. The rest can be "toured" and read through, but each part of the content should be understood and mastered with emphasis. Because the internal circuit diagram of the CNC system is quite complex, and the manufacturer does not provide it. Therefore, there is no need to make it clear in detail. For example, nx-154 four axis five link blade processing machine adopts a-b10 system. We should focus on understanding the function of each part, the function of each board, the destination of the interface, the meaning of LED lights, etc. Now there are many types of CNC systems, which are updated quickly. Different manufacturers and models often differ greatly. We should understand their commonness and individuality (particularity). Generally, people who are familiar with the maintenance of Siemens CNC system may not be proficient in troubleshooting A-B system. Therefore, we should see more and constantly learn and update knowledge

2. read and digest the electrical diagram more

for each electrical component, such as contactor, relay, time relay, etc., as well as the input and output of PLC, it should be noted on the electrical diagram one by one. Take a simple example, for example, if 1A1 is the contactor that starts the hydraulic pump motor 1m, its normally open and normally closed contacts should be marked in the figure, and the direction of the glue sand on the blade and the pot wall should be taken. Therefore, the normally open or normally closed contact 1A1 on its corresponding page can be marked with the hydraulic pump motor on. For large-scale CNC machine tools, the electrical diagram has dozens of pages, or even hundreds of pages. To understand, it means that the function of each component takes a long time. Sometimes, the function of this element may not be clear after the first or second reading. You should read it more and write it after digestion. Therefore, the starting hydraulic pump motor 1m mentioned just now should also clearly indicate which external output of PLC drives the action of contactor 1A1, and the context should be clear. For some block diagrams in the electrical circuit diagram, such as the driver of each axis, it is only a block diagram. As long as you know a certain control condition (on-off condition), you can wait for time to study and consider the detailed things. The electrical symbols of various countries are different, so we must first understand them clearly. For the thick PLC statement tables prepared by the manufacturer, you should also read them more, master their programming language, and annotate and translate them in Chinese on the basis of understanding. This can greatly save the time of troubleshooting in the future. If you get familiar with the electrical diagram and PLC statement table after a fault occurs, it is bound to cost a lot of time and often lead to wrong judgment

3, we should look at the hydraulic and pneumatic diagrams and digest them deeply.

for the mechanical, hydraulic and pneumatic diagrams of CNC machine tools, we should understand their functions and context. It should be noted on the drawings one by one, such as Germany Coburg CNC gantry milling accessories, tool installation action is relatively complex, and its diagram should be broken down, such as which solenoid valve acts to lock the tool? What are the corresponding PLC outputs and inputs? It is indicated in the figure that in this way, from electrical to mechanical action, we should focus on the parts with close relationship between machine and electricity. For example, Italy INNSE CNC milling machine adopts electro-hydraulic proportional valve technology, and we should focus on understanding its role and function, especially its adjustment method and adjustment data, static and dynamic proportional valve current and the pressure of the corresponding balance pump, both electricity and machine, electromechanical integration, Master a variety of skills, so that the ability to solve problems is great

4. read more foreign languages and improve your reading ability in foreign languages of your major

don't know foreign languages, especially English. It is impossible to understand a large number of foreign technical materials, and relying on translation alone is often not ideal. It's hard to read the technical materials in foreign languages at the beginning. There are many new words. After reading and remembering more, there are only so many professional words in common use. Later, it looks fluent. A competent maintenance personnel should basically master language tools

second, ask more

1. Ask more foreign experts

if you can have the opportunity to go abroad for training or foreign experts come to your factory to install and debug machine tools, you'd better have the opportunity to participate. This is the best learning opportunity, because you can get a lot of first-hand information and machine tool debugging methods and skills. For example, after the accuracy of each axis is measured by laser, how to adopt the methods of high-precision 24bit SA/D, automatic file change with sampling frequency of 200Hz, and full force resolution of 1/1000000 line correction. Ask more questions, and make it clear if you don't understand. Through this period of time, you will gain a lot, and you can get a lot of internal information and manuals (which are confidential to users). When the machine tool is put into formal production, it should also be often connected with the outside world

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