Most Common Defects and Solutions on Automotive MIM Parts

With the constant development of MIM technology, it has been applied to more and more industries, and it is essential since been used in automotive. Whilst there are some common defects in the metal injection molding process.

1. Lack of Injection

Lack of injection is the phenomenon that mold cavity cannot be completely filled, the main reason is the stagnation. It occurs due to there is a relatively thin structure near the gate, and the melt encounters relatively large forward resistance during the injection molding process. If the melt does not flow at this point and there is no heat to replenish and have solidified, it will cause lack of Injection.



2. Jet Pattern
The jet pattern is the trails that stream from the gate along the flow direction, bending like a sneak trail. When this happens, we can apply an antiknock pin in front of the gate to prevent stream jets and also to enlarge the gate cross section.



3. Top Raised

When ejector ejecting parts, and the workpiece is not fully cooled solidification, mold release force, leading to parts in the mandrel head position is convex, higher than the normal surface of the workpiece. Under this circumstances, by reducing the ejection speed and mold temperature, to extend the cooling time could be working.

MIM technology has become the most active cutting-edge technology in the new manufacturing industry

Metal Injection Molding (MIM) is a new near net- forming powder metallurgy technology which is formed by bringing powder metallurgy in modern injection molding technology. Its basic MIM process is: mixing metal powder and binder evenly at first. Then granulating the mixture, and injecting into mould cavity in plastic state to shape product. Using chemical or thermal decomposition method to remove blanks, final products will be obtained finally after sintering.

Compared with traditional process, metal injection molding (MIM) have several advantages like high precision, uniform organization, superior performance, low production costs. Its products are widely used in electronic information engineering, biomedical equipment, office equipment, automotive, machinery, hardware, sports equipment, weapons and aerospace industries. Therefore, the international generally believe the development of metal injection molding will lead to revolutions on part forming and processing, known as "21st century molding technology."

The Parmatech company from California invented this technology in 1973, in early 80s, many European countries and Japan companies also put a lot of effort on technology research, and promoting. Especially in the mid-eighties, industrialized technology development is more rapid, growing at an alarming rate every year. So far, more than 100 companies from the United States, Western Europe, Japan etc… more than a dozen countries and regions, engaged in product development and sales. Japan is very active in the competition, and performs outstanding. Many large companies are also involved in the promotion of MIM, including Pacific Metal, Mitsubishi Steel, Kawasaki Iron and Steel, Kobe Steel, Sumitomo Mining, Seiko, Epson, Datong Steel, and so on. At present, Japan has more than 40 companies specialized in MIM industry. The sales value of MIM product has already surpassed Europe and caught up with the United States. MIM technology has become the most active cutting-edge technology in the new businesses. It’s the world's pioneer metallurgical technology, representing the main development direction of powder metallurgy Technology.

Metal powder injection molding technology combines the plastic molding process, polymer chemistry, powder metallurgy technology, metal materials and other multidisciplinary. It can be said a new change for manufacturing industry. The process not only has the advantages of conventional powder metallurgy technology --no need cutting or cutting less, high economic efficiency, but also overcomes the shortcomings of traditional powder metallurgy such as material uneven, low mechanical properties.
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MIM sintering problem

Sintering problem caused by one of the most important direct consequence is to make the product size change and affect the final size of the product accuracy, in the early days of the MIM technology development, the deformation and dimension precision of products is not high, once become the key factor of the MIM technology industrialization, the MIM a process with the final when sintering, the density will produce large volume shrinkage, dimension change is very big, sintering the need for performance, need to control the density of sintered body, magazine content and organization, and its composition, density change is bound to affect the size and dimension precision of products.

Original article link：http://www.zcmim.com/article/mim-sintering-problem_1.html

MIM Technology Becomes An Excellent Process Generally

Due to adopt injection molding, MIM technology can produce a variety of complex shapes. All customize various parts can use MIM technology, saving a lot of machining process. As in flow state, filling cavity evenly to form, cavity pressure in each point and density are consistent. MIM technology eliminates inevitable density gradient of traditional powder metallurgy forming caused by suppressing direction, can obtain near net shape parts with uniform structure, excellent mechanical properties.

Original article link：http://www.zcmim.com/article/mim-technology-maepg_1.html

The Development Direction of MIM Technology in Mechanical System

Modern MIM technology（http://www.zcmim.com/） application in mechanical manufacturing is developing along two directions:

A. making high load parts
B. making complex high dimensional accuracy parts, and makes the final mechanical processing to the minimum.

Original article link：http://www.zcmim.com/article/mim-technology-tddoti_1.html

the development of MIM technology in developed countries

The United States, Europe and Japan and other developed countries in the world in the early 1990 s was basically completed the MIM technology to the development of MIM industry shift, MIM industry in China and abroad overall level gap in about 10 to 15 years.Favorable time in manufacturing industry development in our country at present, the MIM technology application space is big, product market prospect, this undoubtedly for our country to speed up the development of MIM industry provides a rare good strategic opportunity.

Original article link：http://www.zcmim.com/article/mim-technology-tdomti_1.html

Is There Any Limit for MIM Product’s Weight?

Like any other technology, MIM technology(http://www.zcmim.com) also have limit. Maximum weight for product is 240 grams (from economic point of view, general limit weight is less than 50 grams). Some geometric features will have problem too (ultra thick or thin section). ZCMIM will advice you suitable solution for the best design.

Original article link：http://www.zcmim.com/article/mim-technology-ital_1.html

Is There Any Limit for MIM Product’s Weight?

Like any other technology, MIM technology also have limit. Maximum weight for product is 240 grams (from economic point of view, general limit weight is less than 50 grams). Some geometric features will have problem too (ultra thick or thin section). ZCMIM will advice you suitable solution for the best design.

Original article link：http://www.zcmim.com/article/mim-technology-ital_1.html

Is There Any Limit for MIM Product’s Weight?

Like any other technology, MIM technology also have limit. Maximum weight for product is 240 grams (from economic point of view, general limit weight is less than 50 grams). Some geometric features will have problem too (ultra thick or thin section). ZCMIM will advice you suitable solution for the best design.

Original article link：http://www.zcmim.com/article/mim-technology-ital_1.html

Italian Customers Visit ZCMIM

Italian company B** Visit ZCMIM Yesterday. They are a solution company for automatic production equipment. Products involved in a wide range, from government, military and fashion products. This time they mainly would like to know about our factory and price level. Their comment for factory is clean and well-equipped. Though customer’s samples are too simple and not suitable for MIM technology, they will choose appropriate product to us for future cooperation. At the same time, their product manager and project manager will come visit our booth at WORLD PM 2016 congress and exhibition in Hamburg, Germany during 9th~13th Oct 2016. Welcome all your coming!

Original article link：http://www.zcmim.com/article/mim-technology-icvz_1.html

MIM Technology – Debinding Process

In order to facilitate forming, MIM technology has added a large number of binder (15~20%) in its raw materials. These binders must be removed completely before sintering process. Different feedstock system requires  different ways of degreasing. As majority of enterprises are not familiar with the use of feedstock, they can not use debinding technology correctly and reasonably. Any debinding defect will affect sintered products quality directly and affect products yield rate directly. Equipment failure is mostly caused by improper operation in process of debinding, which is not related to the structure and quality of equipment.

Original article link：http://www.zcmim.com/article/mim-technology-dp_1.html

Application Characteristics of MIM Technology

Using MIM technology to develop metal parts’ geometry, we should pay attention to the flexible design of plastic parts, getting rid of the limitation of traditional metal processing technology. MIM process can deal with complex shape parts, assess multiple parts, integrate a variety of feature / function into  a single component, enhance product assembly performance, simplified mechanical components and reduce the quality, but also can customize various physical properties according to the expected end use.

MIM is the most cost-effective process for manufacturing medium or large quantity small and complex metal parts. One way to evaluate an alternative is to envision how much machining operations are used to produce a product. Generally speaking, regarding a product required 4 or more process, MIM is the preferred process. Note: for each machining feature, processing cost will increase; while for mold shaping, MIM cost increase little, and even do not increase the cost.

Original article link：http://www.zcmim.com/article/mim-technology-acomt_1.html

Development Trend of MIM Technology

Metalpowder injection molding( referred to MIM) technology is a new near net forming powder metallurgy technology imported from modern plastic injection molding technology.

1. Representative iron base alloy will be developed toward large volume precision products and high quality structural components.

2. Make uniform microstructure and difficult to process high performance alloy.

3. Manufacture general compounded special alloy by enhancing density.

4. Manufacture non - uniform materials, non-crystalline ,  micro-crystal or metastable alloy.

5. Manufacture unique, non general form and composite parts.

Original article link：http://www.zcmim.com/article/mim-technology-dtomt_1.html

The most attractive technical characteristics of MIM metal powder injection molding

MIMmetal injection molding has combined two advantages of powder metallurgy and plastic injection molding technology, broken through shape limit of traditional metal powder die pressing process. At the same time, Taking advantage of plastic injection moulding technology, MIM can efficiently mass produce complex shape parts, such as a variety of external cutting groove, external thread, tapered outer surface, cross through holes, blind holes, concave station, key pins, strengthen rib plate, surface knurling and so on.

Advantages of MIM technology:

A. direct forming sophisticated parts, usual weight of 0.1~200g

B. fine surface finish and high precision, typical tolerance is + 0.05mm

C. good flexibility and wide application of alloys. The products has density of 95%~99%; internal structure is uniform, no internal stress and segregation.

D. High automatic production, no pollution, can realize continuous clean mass production.

Original article link：http://www.zcmim.com/article/mimmetalinjectionmoldingtatcompio_1.html

MIM how to select binder?

Binder is the core of MIM technology, and MIM is an important difference compared with conventional powder metallurgy method. The main function of the binder is to act as a carrier for the flow of the bonded metal powder particles and to maintain the shape of the workpiece.

MIM binder should meet the following requirements:

The contact angle of the powder is small, and the adhesion ability is strong, and the reaction is not with the powder;

Injection temperature range of viscosity change is not big, but the cooling viscosity change fast

Non stick mould;

With less dosage, the mixture can produce better rheological properties with less binder;

Metal powder injection molding technology industry

Metal powder injection molding as a kind of advanced manufacturing technology, combined with the powder metallurgy and plastic injection forming technology has the advantages of limitations, breaks through the traditional metal powder die pressing forming process on the shape of the products. Has become the main processing method of precision devices. Among them, the automotive industry accounted for a significant proportion of the MIM industry each year, the global sales of 15 billion U. s.dollars. In Europe, the proportion is 45%, in North America, only 20%, while in Japan, only 18%.

With the continuous development of MIM, MIM technology can system for the processing of different materials, from low alloy steel, stainless steel to difficult to machining high temperature alloy steel. Therefore, MIM may replace the traditional machining and casting process. Compared with the traditional metal processing, its main advantage is that, as a kind of near net shape forming process can produce complex shape parts, can maximize the preparing the final shape of the parts without subsequent machining or only need to use the least amount of machining; material utilization rate is high, suitable for mass production.

MIM parts are first applied to the small displacement diesel engines of Europe and the United States diesel light truck engine. Now this technology has been widely used in the global car, mainly for the production of fuel system components, such as the jet nozzle and the armature.

The development history of MIM Technology

Study on MIM technology in our country began in the eighties of the twentieth century, there have been central iron and Steel Research Institute, Beijing University of science and technology, Central South University, Beijing powder, Beijing Nonferrous Metals Research Institute, Guangzhou Institute for nonferrous metal, Ordnance Department v.2, 53 and other scientific research units to carry out the research of MIM technique. At that time, due to the lack of capital investment and foreign technology blockade, did not make a breakthrough.

During the Ninth Five Year Plan period, in the national "863 Plan", national scientific and technological plans, national defense and the supporting scientific research plan and National Natural Science Foundation funded, MIM research breaks through the technical challenges, made a series of innovative achievements. To the end of 1990s, the formation of small-scale enterprises.

Entering the new century, China's MIM industry has a rapid development trend. Science and technology personnel of the Ministry of weapons industry to organize metal materials, non-metallic materials for MIM technology research. On the basis of the previous research and small batch trial production, the MIM technology is the first in China to complete the process of the development of the laboratory to the industrialization, and the application of the technology is more mature.

 In 2001 introduced German advanced MIM professional equipment established the first industrial scale MIM production line, to start mass production of MIM products, for military equipment upgrading produced a lot of MIM parts, made outstanding contributions to the construction of national defense. At the same time for the domestic MIM industry has trained a large number of technical personnel.

2005 start in the Yangtze River Delta, the Pearl River Delta has a small number of MIM manufacturers built, when the scale is relatively small, began mass production of MIM products.

Comparison between MIM technology and precision manufacturing and traditional machining

MIM process and the traditional powder metallurgy method is used in the die casting process of aluminum and zinc alloys, such as low melting point, liquid flow of good material. The product of this process is limited by material, its strength, wear resistance and corrosion resistance are all limited. MIM process can be processed raw materials more.

Precision casting process, although in in recent years the product precision and complexity are improved, but still less than dewaxing process and MIM process, powder forging is an important development, has been applied to the connecting rod mass production. But in general, the forging heat treatment in engineering cost and die life is still a problem, yet to be further solved.

Traditional machining method, recently by automation and enhance the processing capacity, have great progress in the effect and precision, but the basic procedure still do not take off a production step by step (lathe, planer, milling, grinding, drilling, polishing and so on) to complete the shape of the parts.

Machining method is much better than other processing methods, but because of the low efficiency of the material, and its shape is limited by equipment and tools, some parts can not be completed with mechanical processing. On the contrary, MIM can effectively make use of the material, without restriction, for the shape of small, high difficulty of precision parts manufacturing, MIM process is the mechanical processing, the cost is low and the efficiency is high, with a strong competitive edge.

Comparison between MIM technology and precision manufacturing and traditional machining

MIM process and the traditional powder metallurgy method is used in the die casting process of aluminum and zinc alloys, such as low melting point, liquid flow of good material. The product of this process is limited by material, its strength, wear resistance and corrosion resistance are all limited. MIM process can be processed raw materials more.

Precision casting process, although in in recent years the product precision and complexity are improved, but still less than dewaxing process and MIM process, powder forging is an important development, has been applied to the connecting rod mass production. But in general, the forging heat treatment in engineering cost and die life is still a problem, yet to be further solved.

Traditional machining method, recently by automation and enhance the processing capacity, have great progress in the effect and precision, but the basic procedure still do not take off a production step by step (lathe, planer, milling, grinding, drilling, polishing and so on) to complete the shape of the parts.

Machining method is much better than other processing methods, but because of the low efficiency of the material, and its shape is limited by equipment and tools, some parts can not be completed with mechanical processing. On the contrary, MIM can effectively make use of the material, without restriction, for the shape of small, high difficulty of precision parts manufacturing, MIM process is the mechanical processing, the cost is low and the efficiency is high, with a strong competitive edge.

French customers (Surfaces Synergie Groupe) visit the ZCMIM factory

Yesterday plant surfaces Synergie France Groupe customers, to visit the factory is project manager (French) and technology consultant (Korean he is the second to our factory); main customers do luxury metal parts and their surface treatment.

The visit is mainly the project manager to understand our factory. Customers are satisfied with our factory, but to do what luxury brands or SA8000 certification; for SA8000 certification customers currently has two, one is capital to our help, we had requested the SA8000, another is their company in accordance with the audit criteria to review of our factory, which don't need SA8000. These two considerations, they said they would return to the company confirmed.

Regardless of the client for the kind of requirements, ZCMIM will fully cooperate with, because have not done before the luxury metal parts, this is the first time to do such a luxury components, for the MIM process of this is a test, so whether the customer chooses a or two, and on to the SA8000 certification ZCMIM must go through examination, convenient customer cooperation!