Briefly on how to improve the reliability level of CNC machine tools

Most of the manufacturing and processing equipment of most of our manufacturing industries and enterprises are traditional machine tools, and more than half of them are old machine tools with a service age of more than 10 years. Even CNC machine tools, most of which are economical CNC machine tools, are outdated in production equipment and technology. The products processed with this equipment generally have poor quality, low variety, low grade, high cost and long delivery period, so they lack competitiveness in the international and domestic markets, directly affecting a company's products, markets, benefits, and influence. The survival and development of enterprises. Therefore, it is necessary to greatly improve the numerical control rate of the machine tool.

1 Market of CNC machine tools and production line transformation industry

CNC machine tool transformation market

The total number of machine tools in China is more than 380 million units, and the total number of CNC machine tools is only 113,400 units, that is, the numerical control rate of machine tools in China is less than 3%. In the past 10 years, the annual output of CNC machine tools in China is about 0.6-0.8 million units, and the annual output value is about It is 1.8 billion yuan. The annual output of the machine tool is 6%, and the annual output value is 12% (the latter two are 31.6% and 75.4% respectively). Moreover, economical CNC machine tools account for more than 80% of CNC machine tools, and there are not many advanced machine tools such as automatic machine tools. More than 60% of China's machine tools have been in service for more than 10 years; less than 20% of automatic/semi-automatic machines are available for machines under 10 years, and there are only a handful of automated production lines such as FMC/FMS (60% for automatic and semi-automatic machines in the US and Japan). the above). It can be seen that most of the manufacturing and processing equipment of most of our manufacturing industries and enterprises are traditional machine tools, and more than half of them are old machine tools with a service age of more than 10 years. Even CNC machine tools, most of which are economical CNC machine tools, are outdated in production equipment and technology. The products processed with this equipment generally have poor quality, low variety, low grade, high cost and long delivery period, so they lack competitiveness in the international and domestic markets, directly affecting a company's products, markets, benefits, and influence. The survival and development of enterprises. Therefore, it is necessary to greatly improve the numerical control rate of the machine tool.

According to experts' prediction, by the year 2000, the consumption of CNC machine tools in China will reach 24.02 billion yuan. On the one hand, these needs are met by purchasing new equipment. On the other hand, if we make full use of our existing stock assets, replacing and reducing the purchase of new equipment with updated equipment can achieve a multiplier effect. With an estimated demand of 24.02 billion yuan, even if 10% of the demand is realized through the regeneration of equipment, there will be a market of 2.4 billion yuan every year.

CNC transformation market for imported equipment and production lines

Since the reform and opening up in China, many enterprises have introduced technology, equipment and production lines from abroad to carry out technological transformation. According to incomplete statistics, from 1979 to 1988, there were 18,446 technical transformation projects introduced nationwide, about 16.58 billion US dollars.

Most of these projects have played their due role in China's economic construction. However, due to various reasons, some of the imported projects are not functioning properly or even paralyzed, which has affected the efficiency of the enterprise and seriously caused the enterprise to be in trouble. In order to make full use of these equipment and production lines, we conducted a survey on some technological transformation projects that have been introduced for more than 10 years and related to the machinery industry. We have learned that some equipments and production lines have been imported from abroad, some have poor digestion and absorption, spare parts are not complete, improper maintenance, and the results are not working well; some are only introduced to the introduction of equipment, instruments, production lines, neglecting software, technology, management, etc. The project is incomplete, the potential of the equipment can not be played; some can not even start the operation, did not play its due role; some products of the production line sell well, but because the equipment failure can not reach the standard; some because of high energy consumption, products The pass rate is low and the loss is incurred; some have been introduced for a long time and require technical updates. For various reasons, some equipment not only does not create wealth, but consumes wealth.

These unusable equipment and production lines are a burden, and they are also a large stock of assets. If they are repaired, they are wealth. As long as we identify the main technical difficulties and solve the key technical problems of the card neck, we can minimize the investment and revitalize the largest stock assets, and strive for the maximum economic and social benefits. This is also a huge transformation market.

2 Contents, techniques and principles of CNC transformation

The rise of foreign transformation industry

In the United States, Japan and Germany, the machine tool industry is in a sluggish situation today, their machine tool transformation is a new economic growth industry, business is in full swing, in a golden age. Due to the continuous advancement of machine tools and technology, machine tool transformation is an eternal issue. China's machine tool transformation industry has also entered the new industry dominated by numerical control technology from the old industry. In the United States, Japan, and Germany, the use of numerical control technology to transform machine tools and production lines has a broad market, and has formed a new industry for machine tool and production line CNC transformation. In the United States, the machine tool transformation industry is called the machine tool regeneration (Remanufacturing) industry. Well-known companies engaged in the recycling industry are: Bertsche Engineering, Ayton Machine Tool, Devlieg-Bullavd (Dabao) Service Group, US Equipment Company, etc. American Depot has opened a company in China. In Japan, the machine tool transformation industry is called the Retrofitting industry. Well-known companies engaged in the conversion industry include: Otsuka Engineering Group, Gangsan Machinery Co., Chiyoda Machinery Co., Ltd., Nozaki Engineering Co., Hamada Engineering Co., Ltd., Yamamoto Engineering Co., Ltd., etc. The contents of the numerical control transformation of the machine tool and the production line of the numerical control transformation have the following main contents:

The first is to restore the original function, diagnose and recover the faulty parts of the machine tool and the production line; the second is NC, add digital display device on the ordinary machine tool, or add CNC system, transform into NC machine tool and CNC machine tool; It is a refurbishment. In order to improve the accuracy, efficiency and automation, the mechanical and electrical parts are refurbished, the mechanical parts are reassembled and processed, and the original precision is restored. The CNC system that does not meet the production requirements is updated with the latest CNC; the fourth is technology. Updates or technological innovations, in order to improve performance or grade, or in order to use new processes and new technologies, carry out large-scale technical updates or technological innovations on the original basis, and greatly improve the level and grade of renovation.

The criteria for assessing CNC transformation are as follows:

The investment of the transformation is within 30% of the price of the new machine tool, and 70% to 80% of the use efficiency can be achieved, which is considered to be successful; the recovery period of the transformation input fee is lower than the recovery period of the purchase of the new machine tool (generally 5~) Less than half of the 6 years) (generally 2 to 3 years), the transformation is valuable.

There are exceptions. For example, if the key equipment of a project is purchased from a foreign country and its delivery time and price are unacceptable, the evaluation criteria for its transformation should be considered separately.

The pros and cons of CNC transformation

Reduce investment and short delivery time

Compared with the purchase of a new machine tool, it can generally save 60% to 80% of the cost, and the transformation cost is low. Especially for large and special machines, it is especially obvious. Generally, large-scale machine tools are rebuilt, only 1/3 of the cost of new machine tools is purchased, and the delivery time is short. However, in some special cases, such as the production and installation of high-speed spindles, automatic tool changers and automatic pallet changers, it is too laborious and costly. The cost of retrofitting is often increased by 2 to 3 times. Compared with the purchase of new machine tools, only 50 investment can be saved. %about.

Mechanical performance is stable and reliable, limited structure

The basic parts such as the bed and column used are heavy and solid casting components, not the welded components. The modified machine tool has high performance and good quality and can be used as a new equipment for many years. However, due to the limitations of the original mechanical structure, it is not advisable to make a breakthrough transformation.

Familiar with equipment, easy to operate and repair

When purchasing a new device, it is not known whether the new device can meet its processing requirements. The transformation is not the case, the machining capacity of the machine tool can be accurately calculated; in addition, due to the use of the machine for many years, the operator has already understood the characteristics of the machine tool, and the training time is short and effective in operation and maintenance. Once the modified machine tool is installed, it can be fully loaded.

Take advantage of existing conditions

You can make full use of existing foundations without having to rebuild the foundation as you would when purchasing new equipment. At the same time, fixtures, software programs, prototypes and peripherals can be reused. Taking the machining center as an example, the cost of process equipment generally accounts for more than 10% of the total price of the machine tool.

Can use the latest control technology

According to the development speed of technological innovation, the automation level and efficiency of production equipment can be improved in time, the quality and grade of equipment can be improved, and the old machine tool can be changed into the current level machine tool.