1、附 录 The study of Influence factors on dies life Because the ramming processing has the productivity to be high, the material use factor is high, the pressing part precision high, the complex degree is high and interchangeability good and so on characteristics, therefore, in the industrial production
2、, applies especially in the production in enormous quantities very widely. But the ramming mold in the cold stamping processing is also essential. The ramming mold general structure is complex, the accuracy requirement is high, the production cost is also high. In the ramming process, the ramming mo
3、ld as a result of long-term reasons and so on attrition, distortion, break has the expiration, thus causes the enterprise production cost to stay at a high level. Therefore, the exploration enhances the ramming molds service life efficient path to have the important meaning regarding the enterprise
4、development。 1 The influence ramming die lifes primary factor to enhance the ramming die life, must to the mold which expires carry on the analysis, understands and grasps the expiration reason and the influence die life primary factor. Through the research discovery, affects the ramming die life th
5、e primary factor to have the following several aspects: 1.1Mold material (1) mold material smelting if the quality of die steel contains more objects or too much carbon steel, will seriously reduce the impact toughness of steel, anti-fatigue and fracture resistance, causing an early fracture die , b
6、locks and cracking, etc. collapse. (2) mold material in the heat die machining process must be carried out in the quenching and tempering heat treatment and so on. The level of heating temperature, the length, the size of the cooling rate, the protection measures, such as the choice of process param
7、eters will affect the die life. (3) the performance of the workpiece material hardness of various materials, strength, wear resistance, corrosion resistance, plastic deformation resistance, fracture resistance, fatigue resistance and other properties of hot and cold are different, different properti
8、es of the process of stamping the workpiece material the impact of the press are different, such as the stamping of the workpiece material hardness will speed up and increase the wear and tear mold； stamping parts hardware and sticky material (such as stainless steel) when heating large, easy-stick
9、mold, clean-up will not be timely speed up the die wear and reduce the service life of molds. Therefore mold material must be based on the selection of the workpiece material. 1.2 Die structure (1) die form of die structure of the structure is based on the shape of stamping parts to the design of th
10、e same stamping, mold can form a very wide range of choices, if the mold structure is irrational and the stress concentration may lead to fracture failure. (2) stamping parts stamping parts of the shape of the shape of more complex structures will be more complex molds, stamping dies when the local
11、increase wear and tear or deformation, damage, will reduce the life of mold. (3) parameters Die Blanking Dies parameter space, punching power, discharge, and up boundary value, etc., which blanking die gap of life most affected, such as a reasonable space, long life molds； gap is too large or too sm
12、all, will reduce die life. (4) Die Die-oriented agencies agencies or non-oriented low-precision-oriented, rigid poor will aggravate the die wear and reduce die life. 1.3 If the press situation in low-precision press-oriented, poor stiffness, high incidence of eating mold-mode and speed up the wear a
13、nd tear on the life of a great impact on mold. 1.4 Use and maintenance of molds including mold installation, transportation, preservation and maintenance of lubricants, such as the use and operation. 2 Improve the stamping die life in an effective way of stamping, the die service life of high-mode e
14、dge can reduce the number of repair and installation time debugging tool to increase the effective working hours and raise labor productivity, reduce cost of production stampings. Life of stamping dies for the impact of the main factors, there are the following types of stamping dies to enhance an e
15、ffective way of life 2.1 Selection of a suitable wear-resistant materials in general, in the stamping production stamping parts according to material and technical requirements, production batch size, the premise of ensuring the economy as far as choice of materials with high wear resistance and the
16、 necessary heat treatment process. Mold materials commonly used are: (1) Cr12 steel types, including Cr12Mo, Cr12MoV: cold stamping die for a wider range of alloy tool steel, has a high hardenability, hardened and wear-resistant ability. (2) Cr4W2MoV steel (that is, 120Cr4W2MoV): this material with
17、Cr12 steel types, compared to small eutectic carbide, and a more even distribution, have a high hardenability, hardening, and also has higher mechanical properties and wear resistance. W, Mo, V elements help to improve the stability of steel for the use of chemical treatment to improve die life cond
18、itions provide a favorable environment. (3) W6Mo5Cr4V2Al steel: high hardness, can be hardened to HRC 66 68, wear resistance, and alloy steel than the average life expectancy of the mold can increase more than 4 times. Red system for wear and tear on the mold particularly materials such as nickel ch
19、romium titanium, fiberboard and other materials laminated glass. (4) carbide: high hardness, can reach more than HRC85. Excellent wear resistance, hard alloy die life tool steel die than the average 30 50 times. With the CNC wire cutting, EDM processing methods, such as a wide range of applications,
20、 the scope of application of carbide mold growing. Of course, the better the wear resistance of die materials, the general prices of the more expensive materials, processing costs are also higher, so when the economy is also a selection to one of the important factors to consider. 2.2 Die Mold Surfa
21、ce Treatment Surface Treatment includes cremation strengthen and chemically enhanced in two ways. (1) strengthen the EDM EDM is enhanced carbide conductive material, such as electrodes, and metal in the air spark discharge between the workpiece, the use of spark discharge energy release, so that inf
22、iltration of electrode material, covering the surface of the mold to form a strengthening layer. EDM has improved the work of strengthening of the physico-chemical properties of the surface to improve the metal surface hardness, wear resistance, corrosion resistance, mold life can be extended 2 to 3
23、 times. Enhanced surface hardness up to 68 72HRC. (2) chemically enhanced are chemically enhanced nitriding processing, handling boronizing. Nitriding treatment of liquid nitriding, gas nitriding and plasma nitriding glow. Metal surface nitriding through the formation of hard nitride layer, the hard
24、ness of up to 65 69HRC, nitriding the surface with high hardness, wear resistance, heat resistance, high fatigue strength and corrosion resistance. Nitriding for die life improvement than non-nitrogen 2 to 3 times.Nitriding depth of up to 0.12mm, hardness 1200HV. As a result of nitriding in the mold after the nitride layer formed on the surface of protective film, greatly reduced the friction coefficient, can improve die
