表面覆层技术在模具制造中的应用.doc

表面覆层技术在模具制造中的应用Application of surface coating technology in die manufacturingJian Ping CuiAbstract cladding technology as a way to improve the surface quality of mold, greatly improved the service life of the mold. The main principle is the use of physical vapor deposition (PVD), plasma coating technology, multiple layer composite technology, forming a reinforcing layer on the surface of the mould, metal ceramic film, this film has the function of abrasion resistance, corrosion resistance, because this membrane used materials and aluminum, zinc and other metal affinity or reaction solution, so it can greatly improve the performance of die casting die and die bonding phenomenon does not occur.Coating technology, physical vapor deposition (PVD Technology)1 IntroductionDomestic mold industry has developed rapidly, the output value has reached about 50000000000 yuan, the service life of the die is relatively low, only the equivalent of foreign 1/3-1/5, due to the quality of the mold surface caused by the loss of over a billion yuan a year. The surface quality of the mold has a great influence on the service life of the die.Three reasons for the damage of dies and the limitation of die life are as follows: 1) the viscosity (soldering) and chemical erosion damage of liquid metal aluminum. 2) wear and corrosion. 3) thermal fatigue cracking. Pointed out that the relevant domestic aluminum melting loss test, when the mold material hardness is 45HRC, aluminum melting loss without surface treatment rate as high as 54.90%, when using salt bath Sulphonitrocarburizing plus PVD treatment, melting rate decreased to 0.10%. It can be seen that the effect of surface treatment is obviousAluminum Alloy workpiece casting die HEF group steering operating system for cars in the tappet (38CDV5, equivalent to H13 steel) is deposited on the surface of CERTESS SD 3 m thick coating, the hardness can reach 4000 4500HV, using temperature can reach 800 DEG C, but also anti Aluminum Alloy bond, service life increased to 100 thousand times. Is not 67 times of deposition process tappet.The surface coating technology as a method to improve the surface quality of the mold, the research has been carried out in the world famous research institutions and universities, technology is relatively mature, has been used, has achieved very good benefits. Our research in this area is just in its infancy.2 featuresThe surface coating technology including low temperature chemical coating technology and surface modification technology of ultra deep, it is the use of physical, chemical or physical and other technical means to change the material and its surface composition and structure of products, its characteristic is to maintain the inherent characteristics of matrix material, the performance also gives the surface required, so as to adapt to the the special requirements for material technology and service environment, so it is the most active in the field of technology for manufacturing and material science, and is a cross discipline involving surface treatment and coating technology. Its biggest advantage is to prepare surface coatings of good properties of the material are difficult or even impossible to obtain with very little material and energy consumption, in order to achieve maximum economic benefits, it is a kind of high efficient surface modification and coating technology.3 common coating technologiesIncluding the physical gas developed rapidly in recent years, the deposition (JKL), chemical vapor deposition (MKL) technology, thermal spraying, thermal spraying, composite plating, composite brush plating and electroless plating technology of ion implantation.3.1 physical vapor deposition (PVD) is in a vacuum chamber, to strengthen the metal atom evaporation, or by energetic particle bombardment, in a current voltage under the effect of the deposition to attract and work surface strengthening layer. Many kinds of compounds such as titanium carbide, titanium nitride and alumina can be deposited on the working surface by PVD. In a layer of metal ceramic thin film deposition surface of the mould, the film has function of abrasion resistance, corrosion resistance, because the membrane material is used with aluminum, zinc and other metal solution or affinity reaction, so can greatly improve the performance of die casting die and die bonding phenomenon does not occur. For example, a manufacturer of a Aluminum Alloy die castings, product quality requirements are high, due to the occurrence of phenomena of mold sticking, to pressure for an hour to die down grinding time, after surface treatment, eight hours to die down, and clean up very easily.3.2, high-energy plasma surface coating technology, the technology is to increase the surface physical and chemical reactions, access to special properties overlay. The core is to effectively enhance and control the generation and role of cathodic arc plasma. The United States, Japan and Germany have developed this technology. The technology of electrochemical surface modification of plasma enhanced, is currently more active international research and development field for aluminum, titanium and other materials by plasma discharge dimming method, enhanced electrochemical treatment effect, formation of dense alumina and other ceramic oxide film on the metal surface, the substrate has a very high performance surface, is a frontier of advanced technology in the manufacturing process, machining tool and die industry also have application prospect.3.3 multiple layer composite single technology of surface coating can not meet the rigorous working condition of surface engineering in the design of any surface treatment have different advantages and disadvantages, because the performance advantages of different coating materials, the formation of multiple multilayer composite coatings on the surface of the substrate (gradient layer containing extremely gradient) is of great significance. Abroad has carried out single layer coating thickness is nano grade, of more than 100 layers of multiple layers in a multilayer composite coating technology, the prepared coating with high corrosion resistance, toughness and strength, bonding strength and matrix or low surface roughness, the precision high speed cutting machining straight work ten favorable. Abroad has been included in the main areas of development, the nano fine coating materials in the field of research and application will be a new breakthrough. Because the composite coating technology has the functions of wear resistance, high temperature oxidation resistance, heat insulation and so on, it can expand the application range of coating products and prolong the service life. It is a technology that will be developed rapidly in the next first Century. At present, our country has begun to study and obtain preliminary results, but there are still some problems to be solved.4 Application of mould PVD TechnologyTaking the commonly used 4Cr5M0SiVl steel for example, how to obtain the hard film which is not wetted by liquid metal, Colorado, School, of, Mines (CSM), D.Zhong and J.J.Moore film is proposed to multilayer structure optimization: firstly on die steel substrate surface modification, such as the use of ferritic nitrocarburizing and ion nitriding; the 50 100nm with middle layer (adhesion interlayer) such as Ti or Cr; the middle thermal residual between the substrate and the coating due to adjustment caused by the casting operation the excessive stress layer (intermediate graded layer), which can be determined by finite element method, for example, they think, it depends on the work hardening layer selected, when the working layer adopts the Al2O3 layer, the intermediate layer is Ti - Al - N gradient layer; the coating with liquid metal or glass non wetting (non wetting), Al alloy die-casting, can be used CrN, TiAlN, TiCB and Al2O3 etc. The overall thickness of the corresponding multilayer structure is between 58 M.Excellent quality coatings obtained by PVD technology on die parts should rely on high-performance equipment and optimized process parameters. This equipment has the best technical requirements: the coating processing temperature is low; the wound coating is good; the coating is uniform; the enhanced ionization rate and composition of the coating technology; precision control; the rate of deposition; and to multilayer composite coating; we can get the nano structured coating; 9 with PVD and the working mode of CVD; the side edge coating etching, obtain the best quality of coating.The HEF group of France developed and applied plasma enhanced magnetron sputtering (PEMSTM) technology to precisely control the deposition process of coatings. The maximum theoretical density of coating can be achieved by PEMSTM technology. HEF group vacuum coating equipment and technology, therefore, in the world in a leading position. To sum up, the major advantages of HEFs devices and technologies lie in:1) the flow and energy of ions can be independently controlled to obtain the highest density and performance of the coating;2) a unique OES system is used to measure the plasma wavelength to achieve accurate control of coating composition;3) all hard coatings obtained with nano structure (less than 20nm);4) uniform bombardment with low voltage and high vacuum can greatly reduce the sharp corner effect;5) heating the vacuum at the same time to remove the moisture sufficiently and rapidly, and obtain the high quality and high efficiency deposition effect;6) the minimum treatment temperature is up to 80 degrees. It can be applied to coating almost all materials, including aluminum alloys and polymer materials;7) a device that has both PVD and PACVD processing patterns to give technical support to the customers full support.The French HEF group by Ai Fu surface treatment technology (Shanghai) Co., Ltd. in Shanghai Shefu Surface Treatment Technology Co. Ltd. (Shanghai Songjiang) investment into the two series of the PVD/PACVD equipment, hard coatings can now coating are CrN, CrxNY, TiN, TiBN, TiCN, TiALN and DLC diamond film on their surface the PVD coating H13 steel substrate and modified by liquid sulfur carbonitriding or liquid nitrocarburizing also has distinctive characteristics, known as Sursulf/Arcor (Sheshev / a) or Tufftride/ Tenifer (by the HEF in 2001 into the groups German subsidiary Durferrit)5 SummaryThe surface treatment technology is a comprehensive discipline, diverse means, extensive functional, innovative potential, environmental protection, strong practicability and great efficiency, attracted attention from all walks of life, has gradually become an important way to improve the mold quality and prolong the service life.Reference：1 more than Jixing, Waring, Han Congya. Application of surface hardening technology and die life of the mold. The mold design and manufacturing, 2004 (62) 1:62 652, Wang Zhixiang, Lin Jie. Application and progress of new surface strengthening technology in die manufacturing field. Die industry, 2004 (281), 7:52 to 553 Bao Ronghua. Polishing technology for precision cavity mold. Die manufacturing technology, 2004, 6:44 to 46?Applied technology researchOneCui Jianping, lecturer, Department of Mechanical Engineering