As an important means to improve productivity, reduce materials and consumption, reduce product costs, and improve product quality and market competitiveness, molds have attracted more and more attention from various industrial sectors. With the continuous development of industrial technology, the mold is required to have higher and higher precision and longer service life under more demanding and higher speed working conditions. In order to meet these requirements, great efforts have been made in the research and development of mold materials at home and abroad, and many achievements have been made in this regard. At present, the annual output value of the mold industry in the world is about 68 billion US dollars. In 2004, China's mold output value was 53 billion yuan, mold exports were 491 million US dollars, and imports were 1.813 billion US dollars. China has become the country with the largest net export of molds in the world. Although large-scale multi-station progressive dies, precision stamping molds, large-scale multi-cavity precision injection molds, large-scale automobile panel molds, etc. can be produced, the overall technical level is not high, and compared with foreign advanced countries, there is still a big gap, especially the problem of low mold life is very prominent. For example, the total service life of foreign silicon steel sheet stamping dies is more than 5 million times, while the domestic ones are generally 500,000-60 nights, and the maximum is 1.5 million times. The service life of domestic hot forging dies is 500,000 times, and only 3-50,000 times in China. The service life of hot forging dies in foreign countries is more than 12,000 times, and in China it is generally 3,000-5,000 times. There are many factors that affect the life of the mold, but the mold material is an important factor. High-life molds are inseparable from high-quality mold materials. There are few varieties of domestic die steel, poor quality and low performance. Although many high-performance die steels have been developed in China, most of them were developed in the 70-80s of the last century, and for various reasons, the amount of real use is less, and the steel grades are not much. The annual use is less than 10,000 tons. Therefore, the old steel is still mainly used in production, such as CrWMn, Crl2, Crl2MoV for cold mold, 3CrW8V, 6542 for hot mold, etc., in addition, due to the poor forging effect of die steel, improper material selection and heat treatment, etc., the life of the mold is low.
1. Affect the use of molds and the causes of their failure
Since China's accession to the WTO, mold products have been upgraded to the overall level of technical equipment is a vital link, especially the cold extrusion die, it is an important process equipment to achieve less, no cutting processing, and is increasingly widely used in modern production and processing. However, in the cold extrusion process, some important problems are often encountered that hinder the normal production.
1.1 The mold is damaged, and there are three main types of failure
(1) Wear, cold extrusion dies, like most other dies, have a tolerance for a part to allow the wear range. When the mold reaches the wear limit and can no longer be used, this wear is normal tool damage. However, for a considerable number of molds, before the wear limit is reached, due to many reasons, early damage failure of the cavity surface often occurs, such as wear failure, corrosion failure, surface fatigue (pitting or spalling) failure, etc. In this way, it is not possible to manufacture a qualified extrusion.
(2) Deformation, because the load acting on the mold during cold extrusion is very large, the working parts that directly bear the pressure will produce elastic deformation and plastic deformation, such as the elastic expansion of the concave mold cavity, the upsetting and bending of the punch, the axial compression of the ejector rod, the center collapse of the cushion block, etc. In this way, the mold causes normal work and seriously affects the production.

Affect the reasons for the use of molds and their specific factors
   As an important means to improve productivity, reduce materials and consumption, reduce product costs, and improve product quality and market competitiveness, molds have attracted more and more attention from various industrial sectors. With the continuous development of industrial technology, the mold is required to have higher and higher precision and longer service life under more demanding and higher speed working conditions. In order to meet these requirements, great efforts have been made in the research and development of mold materials at home and abroad, and many achievements have been made in this regard. At present, the annual output value of the mold industry in the world is about 68 billion US dollars. In 2004, China's mold output value was 53 billion yuan, mold exports were 491 million US dollars, and imports were 1.813 billion US dollars. China has become the country with the largest net export of molds in the world. Although large-scale multi-station progressive dies, precision stamping molds, large-scale multi-cavity precision injection molds, large-scale automobile panel molds, etc. can be produced, the overall technical level is not high, and compared with foreign advanced countries, there is still a big gap, especially the problem of low mold life is very prominent. For example, the total service life of foreign silicon steel sheet stamping dies is more than 5 million times, while the domestic ones are generally 500,000-60 nights, and the maximum is 1.5 million times. The service life of domestic hot forging dies is 500,000 times, and only 3-50,000 times in China. The service life of hot forging dies in foreign countries is more than 12,000 times, and in China it is generally 3,000-5,000 times. There are many factors that affect the life of the mold, but the mold material is an important factor. High-life molds are inseparable from high-quality mold materials.
There are few varieties of domestic die steel, poor quality and low performance. Although many high-performance die steels have been developed in China, most of them were developed in the 70-80s of the last century, and for various reasons, the amount of real use is less, and the steel grades are not much. The annual use is less than 10,000 tons. Therefore, the old steel is still mainly used in production, such as CrWMn, Crl2, Crl2MoV for cold mold, 3CrW8V, 6542 for hot mold, etc., in addition, due to the poor forging effect of die steel, improper material selection and heat treatment, etc., the life of the mold is low.
1. Affect the use of molds and the causes of their failure
Since China's accession to the WTO, mold products have been upgraded to the overall level of technical equipment is a vital link, especially the cold extrusion die, it is an important process equipment to achieve less, no cutting processing, and is increasingly widely used in modern production and processing. However, in the cold extrusion process, some important problems are often encountered that hinder the normal production.
1.1 The mold is damaged, and there are three main types of failure
(1) Wear, cold extrusion dies, like most other dies, have a tolerance for a part to allow the wear range. When the mold reaches the wear limit and can no longer be used, this wear is normal tool damage. However, for a considerable number of molds, before the wear limit is reached, due to many reasons, early damage failure of the cavity surface often occurs, such as wear failure, corrosion failure, surface fatigue (pitting or spalling) failure, etc. In this way, it is not possible to manufacture a qualified extrusion.
(2) Deformation, because the load acting on the mold during cold extrusion is very large, the working parts that directly bear the pressure will produce elastic deformation and plastic deformation, such as the elastic expansion of the concave mold cavity, the upsetting and bending of the punch, the axial compression of the ejector rod, the center collapse of the cushion block, etc. In this way, the mold causes normal work and seriously affects the production.
(3) Fracture, which is the most common form of damage of cold extrusion die, which is caused by the load exceeding the strength limit of the mold material, such as punch breakage, die and fastening ring cracking, ejector rod fracture, insert fatigue fracture, creep fracture, low-stress brittleness, etc. When the mold parts produce the above-mentioned defects, they cannot manufacture qualified extrusions, which will seriously affect the production plan of the factory. To this end, engineers and technicians need to solve the key problems that cause these defects in a timely manner. Production practice proves that the bearing capacity, working service life, manufacturing accuracy and product qualification rate of each mold are largely determined by the chemical composition of the mold steel, the processing quality of the mold parts and the heat treatment process. In order to produce high-quality and cost-effective extrusions, it is necessary to comprehensively consider the mold structure design, the selection of mold materials, machining, heat treatment, production costs, etc., in order to achieve the due technical and economic effects. 1.2 Statistics of early failure of molds
For any kind of failure cause, it is necessary to understand and analyze the fundamental factors of mold damage, and the primary data can be collected from production practice, that is, social production statistical survey. Based on the appearance of the mold and the results of the internal inspection, find out the decisive factors that affect the failure of the mold, you can find out the characteristics of the mold failure and the root cause of the damage, of course, the mold failure is often the result of the comprehensive action of several factors, in the specific analysis, we must fully consider the mutual influence and organic connection of the various factors. Before analyzing the damage of the mold, a statistical analysis was carried out on the causes of the early failure of the mold, and the data in Shanghai and Japan were different. However, the reasons for the early failure of the mold are mainly due to the poor heat treatment process of the mold and the poor quality of the mold raw materials, followed by the poor conditions of the mold, the poor mold processing method, the unreasonable mold design and the improper forging process of the mold blank. Therefore, in order to prevent the early failure of the mold and prolong the service life of the mold, effective and corresponding preventive measures should be taken from the above aspects.

Mr. Li Houjin, the founder of Zhicheng Mould Company, has been operating in the mold industry for more than 20 years, and has worked in NIKE, ADIDAS, and ACISS companies for many years, and became the first person to shoot EVA slippers in China in 1996, filling the gap in the history of domestic slippers. From 1998 to 2013, he won 11 invention patents. In 2005, PVC air-blown slippers were developed, which was unprecedented. Since then, Chinese slippers have gone to a glorious peak era.