|
|
| Keywords of this article:
machine tool
precision
|
|
| Issue date:01/06/2006 |
| Chinamac Journal (CMJ) - Jun 2006 Issue |
| Source:Chinamac Journal |
| Chen Changnian, The Society of Automotive Engineers of China |
|
| This article explains the significance of the development of auto parts manufacturing equipment in China, then indicates what types of equipment are used in modern manufacturing equipment, how their markets are, and those types that China imports most. |
Great strategic significance in developing auto manufacturing equipment
The automobile industry in China accounts for about half of the output value and profit of the equipment manufacturing industry. The practice from home and abroad proves that the development of automobile industry, on one hand, depends on the technological advancement of machine tool industry; on the other hand, it drives the development of machine tool industry. Over the past decade or so, the automobile industry in China has become the leading consumer of machine tools, contributing to about 40% of the total machine tool consumption. Meanwhile, more than half of the investment in automobile industry is for the procurement of machine tools, with about 80% going to imported machine tools. This is the main reason for the high-speed growth of China's consumption and import of machine tools.
From a historic perspective, the development of automobile products is bound to go along with that of equipment manufacturing industry, and vice versa. For example, the automatic line of combination machine tools had dominated the production of automobile industry for about a century. With the influx of competition, the cycle of automobile replacement of older generations shortened to four years from dozens of years. However, this dominating type of equipment found no way to adapt to the new situation because of a lack of flexibility. In the 1980s, cooperating with a top machine tool maker INGERSOLL, the automobile giant Ford developed a type of high-speed machining center which offers both high flexibility and high efficiency. With this as one of the different parts, a flexible automatic production line was developed, which speeded up the development of new generations of cars and enhanced an enterprise's efficiency and flexibility. This is one of the reasons why dozens of new cars are marketed each year.
On one hand, the level and quality of a vehicle depends on the manufacturing equipment used; on the other hand, the international competitiveness of a country's automobile industry and that of a particular auto maker is determined by how advanced the equipment is used and how much the production cost is. It is the employment of a great number of advanced CNC equipment that has taken China's car equipment industry to a time that boasts of flexible production. And from the advanced equipment the automobile industry finds the momentum to move forward non-stop.
China has a big market for auto-manufacturing equipment
China will be the biggest market and the largest producer of automobiles in the world. According to the strategy of development, China's automobile output will reach 14 to 18 million units in 2020, topping the world in this respect. At the same time, China will become one of the great powers in the automotive industry worldwide, represented by the possession of advanced manufacturing technology and equipment.
Additionally, all automobile manufacturers, and the parts makers in particular, shall continuously improve their manufacturing technology and equipment in order to survive against intense market competition. It can be asserted that the automobile industry will be a leading consumer of machine tools during the long period of time of China's fulfillment of industrialization.
China's automobile manufacturing equipment is polarized and is, in general, underdeveloped. Figuratively speaking, modern weapon and rifle coexist. On one hand, we boast model plants of, say Shanghai GM, which are equipped with the world's most advanced agile and flexible production lines; on the other hand, there are many old state-owned automobile enterprises such as Jinan Truck Co Ltd, whose percentage of CNC machine tools was only 1%, as surveyed in the year 2002.
Overall speaking, all joint ventures and some private enterprises (such as Wanxing Group) have entered into the era of flexible manufacturing and reached the level in the 1990s. Some auto parts manufacturers, on the contrary, are manufacturing low-quality products on general, or non-CNC, machine tools for only the low-end market.
Modern auto-manufacturing equipment and the popular types imported to China
The automobile manufacturing equipment can be divided into those for complete cars and those for parts.
For complete car manufacturing, there are four types of equipment: car body welding and assembling line, spraying line, and punching line.
(1) Punching line: it is counted that out of the 2,000 plus parts that a car has, more than 40% are pressed parts, including the external parts and structural parts of the car body, and small and medium-sized pressed parts. Presently in China, automatic and semi-automatic punching lines are mainly used in car manufacture. Flexible punching lines are the next generation. Punching line is the only major type of automobile manufacturing equipment that Chinese-made ones dominate the market. However, China still lags behind foreign countries in advanced punching technology.
(2) Nearly all car welding and assembling lines used in China are imported.
Car body welding line and complete car assembly line are the weakest ends of China's automobile manufacturing equipment industry.
Presently, the auto-assembling line is being developed to be flexible and "zero defect". Flexibility is achieved by the use of a great number of welding and assembly robots.
(3) Spraying line: Such line is mainly composed of spraying robots and devices for electrophoresis, drying, coating and conveyance and so on. It basically relies on import due to China's absence of the technology to integrate the process system, logistics system and information system into a flow production line.
Parts manufacturing equipment:
(1) Production line for metal cutting machine.
In terms of value, 70% to 80% of metal cutting machine production lines for manufacturing car parts are imported. The percentage, however, is on the decline in recent years following the transfer of production of many internationally famous manufacturers of machine tools, plus the acquisition of internationally famous machine tool makers by Chinese machine tool makers. With respect to metal cutting machine production lines for manufacturing truck parts, Chinese-made products are mostly used.
Below is an analysis of several popular types of metal cutting machines:
1. Flexible transfer line (FTL). Such line includes high-speed machining centers (see the description as below). It is basically applied to manufacturing engines. According to incomplete statistics, from the end of last century up to now, about 100 of such lines have been or are going to be installed in China, with the unit price of each line at about US$20 million. And 90% are imported, from mainly Germany, Japan, Italy and USA.
2. Dual spindle/dual turret multi-axis CNC turning/milling center, or flexible manufacturing cell (FMC). They are equipped with C and Y axes and power tool head, as well as automatic material loading/unloading unit (with robot). Integrated with material storage, conveyance and automatic control functions, they form a FMC. Whereas such device can meet the demand of shaft-type auto parts for "one on down" production, several hundred and even several thousand of such devices have been put into production in recent years - of which 90% or so are imported from Japan, South Korea and Taiwan mainly.
One special point. As more and more auto parts are machined instead of ground, CNC lathes are required have strong turning capability.
3. Different types of CNC grinding machines and special-purpose CNC grinding machines, such as high efficiency and high accuracy centerless grinders equipped with automatic material loading/unloading device (with robot) to form the grinding cell; high efficiency and high accuracy CNC grinders for crank shafts and cams, specialized grinding machines for universal joints, and so on. Almost all of such machines are imported, mainly from Germany, Italy, Switzerland and Japan.
4. High-speed 5-axis bed-type/gantry milling machine (machining center) for dies and molds. Such machine features high speeds and good rigidity. The gantry machining center offers a five-side function and a head changing mechanism in order to satisfy the spindle speed requirements of different machining procedures - milling, boring and drilling. All such machines are imported. Several hundred of such machines have been put into operation. Main suppliers are Germany, Switzerland, Japan and Italy.
(2) Precision forging: it is a near net shape forming technique for producing blanks of key auto parts. Precision forging machine relies on import due to the poorer quality of Chinese-made machines of this kind.
1. Hot precision forging line and manufacturing cell: the precision of hot precision forged gears by BLM has reached the DIN6 level, coupled with 20% to 30% material saving and 15% to 30% increase in mechanical performance.
2. Cold precision forging (cold extrusion) line and manufacturing cell: the US produces more than one million cold extruded parts each year. 80% of them are auto parts.
3. Warm precision forging line and manufacturing cell: for this technique, materials are forged after heated to 700°C to 1,000°C. It offers the advantages of both hot and cold forging. The US produces warm forged parts which account for about half of its output of precision forged parts.
4. Die forging machine/manufacturing cell: Forged blanks of auto parts are all made by die forging. Local manufacturers are weak at producing dies and loading and unloading devices for die forging.
5. Powder metallurgic sinter forging equipment. Foreign countries have a rapid development in powder metallurgic sinter forging technology and their weight accuracy of powder forged link rod can reach 1%.
6. Internal hi-pressure forming technique. This is the new and advanced technology for manufacturing hollow, lightweight structural parts. The internal hi-pressure formed parts are lightweight and very strong, and are composed of fewer pieces with fewer welds. Such technology sees a rapid development in Europe and America.
7. Spin forming equipment. With such technology, the processing precision is high, and strong wheels, fellies and spokes with convertible cross-sections can be produced.
(3) Casting line:
Big-tonnage die casting machine/manufacturing cell (aluminum-alloy castings) relies on import. In particular, Chinese-made dies vary greatly.
Precision casting line (cast-iron pieces) relies on import. The automatic key core system by Loramendi, a Spanish company, is most often used.
(4) Laser processing equipment. Such equipment includes laser cutting equipment and laser welding equipment. Laser weld blank draw forming is an advanced technology being developed strongly internationally. With such technology, steel plates of different materials and thicknesses are welded into a blank, which is then stamped as a whole. Consequently the weight of parts can be reduced while the matching quality of the complete car can be improved, and the material consumption can be decreased with a higher productivity. This type of equipment relies on import as well.
The car body 3D CNC laser cutting is a recently developed technology for flexible manufacturing, replacing the traditional manufacturing mode of having manual cutting and using cutting dies. The preparation cycle for production is shortened to 5 days from 2.5 months.
(5) CNC tooling system. The CNC tooling systems for auto parts manufacturing are mainly imported. Modern processing of auto parts and dies has been done at high speeds, levying high requirements on tooling. Now solid carbide tools, hard alloy coated tools (including CVD and PVD), ceramic tools, CBN tools, PCD tools, sintering laminated tools, and others, have come into use.
Furthermore, the monitoring devices for high-speed cutting tools, connecting tools for tooling systems, dynamic balance equipment for high-speed rotary tooling system are subject to higher requirements.
It has to be pointed out that the "Smart Tools" have been applied in modern production lines for auto parts processing. These "Smart Tools" are a series of specialized, high-efficiency tools for processing particular parts. Meanwhile, internationally famous suppliers of CNC tools also provide what are called "total solutions", which include high-speed cutting software packages, and cutting tool usage (replacement or regrinding) services.
Long way to go for localization of China's automobile manufacturing equipment
In the 1980s, China's automobile industry turned its emphasis to car manufacturing, but the machine tool industry in China did not adapt to this change well. For a long time, the rate of domestic production of car equipment has been low, at 20% only. Fortunately there are still some highlights, for example, the automobile punching line, CNC gear processing machines. And in recent year, Dalian Machine Tool Group (DMTG) and Shenyang Machine Tool (Group) Co Ltd (SMTCL) have provided for auto makers flexible production lines composed of high-speed machining centers. Furthermore, several thousand domestically made CNC machine tools have been in use among auto makers.
Overall speaking, there is a wide gap between China and the world in terms of the level of machine tools:
(1) A different in self innovation: Last year I visited 20 famous machine tool manufacturers specializing in automobile manufacturing equipment in Europe, Japan and three other nations. I realized that the gap between China and foreign countries in modern engine manufacturing technology, high-speed machining center, advanced machine tools such as manufacturing cells composed of high-end hybrid machine tools, has become wider. The main reason is our absence of an independent innovation system for manufacturing technology. Additionally, there is a big difference in the investment in the R&D of manufacturing technology in terms of human and financial resources.
Modern automobile manufacturing equipment has a heavy emphasis on "solution". Now international first-class machine tool makers has completed the revolution from selling equipment to providing "solutions". This requires application engineers to act as senior "grey-collars" with inter-disciplinary talents. This is a new and even a wider gap between China and the international community.
(2) A difference in machine tool performance: Chinese key CNC machine tools cannot meet the requirements of modern cars for precision, precision stability, reliability and service life. For instance, on the international level, processing precision has increased 50 times during 1950 to 2000. There is a difference of 15 years between China and the world's advanced level in processing precision.
(3) A difference in software: there are differences in the control system of production line and in integration technology. China lacks the technology to integrate process system, logistics system and information system into a manufacturing cell or flow production line.
|
| We are collecting readers' comment for improving our website. If you are willing to help, please CLICK HERE to complete a survey. Your comments matter. |
|
|
|
|
| Copyright © Adsale Publishing Limited. Any party needs to reprint any part of the content should get the written approval from Adsale Publishing Ltd and quote the source "Chinamac Journal (CMJ)", Adsale Machine-Building Website - www.AdsaleCMJ.com. We reserve the right to take legal action against any party who reprints any part of this article without acknowledgement. For enquiry, please contact Editorial Department. |
|
| Copyright © Adsale Publishing Limited. Any party needs to reprint any part of the content should get the written approval from Adsale Publishing Ltd and quote the source "Chinamac Journal (CMJ)", Adsale Machine-Building Website - www.AdsaleCMJ.com. We reserve the right to take legal action against any party who reprints any part of this article without acknowledgement. For enquiry, please contact Editorial Department. |
|
|
|
Close
|
|
|
Write a mail to the editor : 
