Ferrite magnet used for motor can be divided into two major types: arc and non-arc magnet according to their shape. Non-arc magnet includes block (bar), ring of axially orientation magnetizing with multi-poles in single (both) sides, ring (cylinder) of radially magnetizing with multi-poles. China began to industrializedly produce ferrite magnets used for motor at the end of 1970s. A tremendous and pleasant change has taken place both in its production scale and structure after over twenty years' development.
A.Production Scale
According to the different production technology it can be divided into four major types: bonded anisotropic rubber magnet, isotropic magnet, dry-type anisotropic and wet-type anisotropic magnet. The amount of producing motor ferrite magnet in China has increased dramatically during the past ten more years and the rate of increasing reaches about 30% per year. The amount of ferrite magnet produced in China is up to 41,000 tons by 2001, in which the sum of bonded anisotropic rubber magnet, isotropic, dry-type anisotropic rubber magnet and wet-type anisotropic magnet is 6000 tons, 8000 tons, 6000 tons and 21,000 tons respectively. Their percentage distribution is shown in the diagram 1.
There are about 400 factories producing ferrite magnets in China, however, the ones who producing in large scale are less than 100. The scale reflects the production centralization situation. About 80% of the total output was made by only ten more enterprises.
B.The supply & demand situation and price situation in the market
At present in China, ferrite magnets are mainly used in motors for toys, automatic facilities, household appliance and so on. A few ferrite magnets are used in high-class motors such as those in automobiles and motorcycles. The products extremely depend on the international market. 70% of the products are exported to abroad or used by the foreign motor enterprises established in China. Only 30% of the products are consumed by Chinese motor enterprises.
The price of ferrite magnets in China has a trend to decrease constantly out of keen competition in the market. Now the market price is very low. The price of bonded anisotropic rubber magnets ranges from about RMB 10,000 to 30,000 per ton. The price of dry-type anisotropic magnet is from RMB 18,000 to 45,000 per ton. And the price of wet-type anisotropic magnet ranges from about RMB 19,000 to 45,000 per ton.
A. The standard of technology & craft
The rapid developments of Chinese motor ferrite magnets benefit from the fast growing demand of the market as well the improvement of the technology. In spite of the differences of the enterprises, the enterprises producing ferrite magnet are developing toward the semi-automatic and full automatic production except that the sorting processing still depends on labor. Most of the technological processes of the bonded anisotropic rubber magnets have adopted semi-automatic production ways including its melting, rolling, precise rolling and pressing. A few amount of enterprises have introduced into advanced technology and adopted the full automatic ways.
The automatic degree of producing isotropic magnet is much higher. A few numbers of enterprises have adopted advanced automatic granulation facilities to make granule and powder. Commonly, the press is automatic. The productive technology of dry-type anisotropic magnet basically is semi-automatic, and productive technology of wet-type anisotropic magnet is mainly semi-automatic.
B. The standard of technique
The technological level of ferrite magnet has been improved greatly during the past ten more years. It mainly benefits from the improvement of the raw material grade and craft & technological level of Chinese ferrite magnets.
The technological level of bonded anisotropic rubber magnets has been upgraded dramatically during the recent five years. For example, the magnetic characteristics could be Br≥240mT, HcbS≥170kA/m, Hcj≥200kA/m, (BH)max ≥l0.8kJ/m3. The dimension tolerance may be controlled within ?.1 mm. The rate of pass of final products can be controlled over 85%. The appearance also reaches the advanced level in the world.
The improvement of isotropic technology mostly reflects on the control of tolerance of product dimension, the enhancement in the percent of pass of the finished products and the consistency of magnetic characteristics. The enhancement of magnetic characteristics was slow before 1997 because the isotropic ferrite magnet used in motor was radial function. After 1997 China began to make the isotropic Ba ferrite magnet material of high radial function, so that the characteristics of ferrite magnets has a great improvement. At present, the magnetic property of axial orientation magnet can be achieved to Br≥225mT, Hcb≥l50kA/m, Hcj≥ 260kA/m, (BH)max ≥ 8.5kJ/m3 ; The radial orientation magnet can achieve Br≥205mT, Hcb≥ 130kA/m, Hcj≥265kA/m, (BH)max ≥ 6. 5kJ/m3.
Moreover, the technological level of dry-type anisotropic magnet has been enhanced greatly too. The magnetic characteristics can go to Br≥370mT, Hcb≥235kA/m, Hcj≥ 240kA/m, (BH)max ≥ 25. 0kJ/m3. The rate of pass of the end products may get to over 80%.
Furthermore, the technological level of wet-type anisotropic magnet has been improved greatly. Now most enterprises can produce the products with material property of up to Y30H-1 (equal to FB4 serial of TDK standard). The rate of pass of the end products has been increased constantly. Different types of products have different pass rate. Generally speaking, the rate is from 60% to 85%.
Compared with the foreign enterprises the production of Chinese motor ferrite magnets has a great difference no matter from production scale, craft and technology level or quality and quality management.
A.Production scale
The production scale is inferior to that of foreign enterprises although there are 100 enterprises producing ferrite magnets in China. The output of foreign enterprises ordinarily is beyond 3000 tons per year. On the contrary, the output of 80% Chinese enterprises is less than 1000 tons per year. Up to now, there is less than 10 enterprises whose output is larger than 3000 tons and no more than three enterprises can produce 10,000 tons a year in China.
B.The standard of craft & technology
The standard of craft & technology of foreign enterprises is very high. They generally have used the automatic production equipment and only a few operating workers are needed. The technological standard of Chinese enterprise in a whole is much lower than that of foreign enterprises although different enterprises and different products have different craft & technology level. Hand-making and semi-automatic craft & technology is largely adopted in the process of sorting, preparing material, shaping and grinding. A large number of workers are needed.
C.Technological standard
Compared with foreign enterprises, the Chinese enterprises have a great difference in the technological level of every type ferrite magnet products. Now we analyze them as following:
Firstly, the main differences of the bounded anisotropic rubber magnets lie in the magnetic characteristics, the control of dimension tolerance, the products consistency, outer appearance and the rate of pass of final products. On one hand, the magnet characteristics of Chinese enterprises are in the range of Br230-260mT, Hcbl55-175kA/m, Hcjl70-250kA/m, (BH) max 10.0~12.5kJ/m, while most of the foreign enterprises are in the range of Br240-270mT, Hcbl65-195kA/m, Hcj200-350kA/m, (BH)max 10. 8-13. 5 kJ/m3. On the other hand, the consistency of ferrite magnet is inferior to that of foreign enterprises due to the bad consistency of raw material, old equipment and back technology. In addition, the control of dimension tolerance is worse than that of foreign enterprises. There is almost no Chinese enterprises can control the dimension tolerance within ?0.005mm. The old equipment and backward technology also bring about the difference in outer appearance and the rate of pass of the final products,Secondly, the technological differences of isotropic products between Chinese and foreign enterprises are mainly in the consistency of magnet characteristics and products. There is no difference between the axial orientation products of Chinese enterprises and that of foreign enterprises concerning about the level of magnet characteristics. Their difference mainly lies in the consistency. On the radial orientation magnet both the magnetic characteristics and the consistency are lower than that of foreign enterprises. The magnetic characteristics of the radial orientation products making by domestic raw material is in the range of Brl90-210mT, Hcbl25~135kA/m, Hcj230-270kA/m, (BH) max 5. 8-7. 0kJ/m3, while the products of foreign enterprises are controlled in the range of Br210-220raT, Hcb 130- 140kA/m, Hcj250-270kA/m, (BH)raax 6. 5-7. 5kJ/m3.
The reasons of the differences on the dimension tolerance control, outer appearance and the rate of pass of the final products are the same as the bonded anisotropic rubber magnets.
Thirdly, the technological differences of dry-type anisotropic products are also mainly showing on the low Br value of magnetic characteristics. The Br value of Chinese products ranges from 340 to 375mT, while the Br value of most foreign products ranges from 360 to 400mT. The low Br value caused the low magnetic characteristics in overall.
The reasons of differences for the dimension tolerance control, outer appearance and the rate of pass of the final products are the same as the bonded anisotropic rubber magnet products.
Lastly, the technological standard of wet-type anisotropic products of Chinese enterprises on magnetic characteristics, the control of dimension tolerance, products consistency, outer appearance and the rate of pass of the final products are also different from that of foreign enterprises.
Concerned about the magnetic characteristics, Chinese enterprises mostly Still remain in the Y30H-1 level (equal to FB4 serial of TDK standard). Although many enterprises announced that they are capable of producing Y30H-2 products (equal to FB5 serial of TDK standard) the products are usually under the level of grade FB5 or only made in a small sum. This is quite different from that of the foreign enterprises whose production magnetic characteristics are usually over Y30H-2 (equal to FB5 & FB6 serial of TDK standard).
The reasons of differences for the dimension tolerance control, outer appearance and the rate of pass of the final products are the same as the bonded anisotropic rubber magnets.
D,The level of Quality
Compared with foreign enterprises, the quality of Chinese ferrite magnets is much lower. The gap is mainly shown on the bad unified characteristic of products and low rate of pass of the finished products. The consistency of products includes magnetic characteristics, dimension and outer appearance etc. Here, we will use Cpk data or the rate of pass of the finished products to illustrate this gap.
Firstly, Cpk of the magnetic characteristics of bonded anisotropic rubber magnets made by Chinese enterprises ranges from 0.70 to 1.33 or so. Dimensional CPK ranges from about 1.00 to 1.50. The rate of pass of the final products ranges from 80% to 90%.
Secondly, Cpk of the magnetic characteristic of isotropic products of Chinese enterprises ranges from 0.70 to 1.33 or so. Dimensional Cpk ranges from about 1.00 to 1.40. The rate of pass of the final products ranges from 85% to 95%.
Thirdly, Cpk of the magnetic characteristics of dry-type anisotropic products of Chinese enterprises range from 0.70 to 1.33 or so. Dimensional CPK ranges from about 1.00 to 1.50. The rate of pass of the final products ranges from 80% to 90%.
Fourthly, Cpk of magnetic characteristics of wet-type anisotropic products of Chinese enterprises range from 0.70 to 1.33 or so. Dimensional Cpk ranges from about 1.00 to 1.50. The rate of pass of the final products ranges from 60% to 85%.
E.The management of quality
Most of foreign enterprises have applied ISO9000 or QS9000 quality system into management. They also strictly adopt statistical technology to control producing processes. On the contrary, only a few Chinese enterprises have adopted ISO9000 or QS9000 quality system into management. The one who can strictly put statistical technology into use during the producing process is much fewer. Obviously the gap is enormous
Generally speaking, there is still a large distance between the domestic enterprises and foreign enterprises that manufacturing motor ferrite magnet. However, ferrite magnets which applying to Chinese motors has the superiority of low cost. We can suppose that in China, the progress speed of manufacturing ferrite magnets applying to motor will remain high in the next 10 years with the development of the world market. The developing tendency of different kinds of ferrite magnets in the next 10 years will be as below:
A.Manufacture scale
The scale of manufacturing hard ferrite magnets applying to Chinese motor has developed rapidly. The average increasing rate is about 12% every year. And the total output will achieve 130,000 tons by 2012, which is the top in the world. The developing speed of front 5 years will be higher than the rear 5 years. We also illustrate the development of the estimated total output and the increase rate with diagram 2 and 3. The development of different kinds of products is not the same. For example, the increase rate of rubber magnets is about 9% per year, and its output will achieve 13,000 tons in 2012; The increase rate of isotropic magnet is about 4%, and its output will reach 12,000 tons in 2012; The increase rate of dry-type anisotropic magnets is about 8%, and its output will achieve 13,000 tons in 2012; The development of wet type anisotropic magnets will become the core of manufacture. Especially, the arc magnets will grow faster. Its increase rate is about 16% and its output will be 90,000 tons in 2012. The number of manufactor will reduce a lot because of the intensive competition. The great output will concentrate in the big manufacturing companies. There will appear manufacturing companies with annual output of or over 20,000 tons by 2012.
B.The supply & demand situation and price situation in the market
With the development of Chinese motorcycle and automobile industries the rate of ferrite magnet used in high-class motors will be raised in a further degree besides that they are largely used in the motors of toys, automatic facilities and household appliance etc. The products will chiefly depend on international market but the degree of dependence will be down. We predict that 60% of the products will export abroad or used by the foreign enterprises in China. Chinese motor enterprises will consume 40% of the products. The market competition will become extremely keen and the price of ferrite magnet will be down continuously with the enlargement of production scale, increase on the number of the enterprises and the establishment of foreign enterprises.
C.The level of craft & technology
The level of craft & technology of ferrite magnets will be raised step by step. Automatic degree will be enhanced greatly. More and more enterprises will be equipped with automatic facilities. A few numbers of enterprises have used automatic production line.
E. Technique level
The technique level of ferrite magnets applying to Chinese motors has been improved a lot in the field of magnetic characteristics, tolerance control of dimension, outer appearance and the rate of pass of the final products. The magnetic characteristics of anisotropic rubber magnet and isotropic magnets will be up to or beyond the standard of foreign countries. The magnetic characteristics of dry-type anisotropic magnets will reach the present standard of foreign countries. The magnetic characteristics of wet-type anisotropic magnet will achieve FB5 series of TDK standard. Part of enterprises will mostly produce the products whose characteristics are equal to the FB5 series of TDK stamdard to fit the automobile industry. Meanwhile, a small number of enterprises are capable of producing the products whose function is equal to the TB6 series of TDK standard.
The rate of pass of the final products of the three kinds of products will be raised but the scope will be small because the rate of pass of the final products of bonded anisotropic rubber magnet, isotropic and dry-type anisotropic magnet has reach such a high level. The three kinds of products will be chiefly improved in their consistency. The rate of pass of the finished products of wet-type anisotropic magnet will be raised greatly and its downline will be raised from 60% to 75%. Of course the consistency of wet-type anisotropic products will be improved too.
F.Standard of quality
The quality standard of ferrite magnets will be enhanced step by step with the improvement of craft & technology and quality management. Among which the most obvious one will be the wet-type anisotropic magnet.
G.Management of Quality
Chinese enterprises will pay much attention to the quality management. There will be more enterprises to apply ISO9000 or QS9000 into management as well strictly and voluntarily adopt statistical technology into controlling during the production processes.
