Development and application of hot pressing inject

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Development and application of dental resin base hot press injection molding machine

development and application of dental resin base hot press injection molding machine Liu Jianhua, Xue Miao, Zhang Jianzhong, Zhang Fuqiang electrical control parts constitute dental resin base hot press injection molding machine, application, elbow people trial produce full base. Results the resin was made of dental resin base by hot pressing and injection molding It is equipped with a fully enclosed protective mesh mechanism to form a complete denture base. Conclusion the dental resin base hot pressing injection molding machine is convenient and practical. Preliminary observation showed that the denture base products had good performance. Most plastic denture bases are made of polymethyl methacrylate. 1 Polymethylmethacrylate is also a thermoplastic resin, with a glass transition temperature of 15, a melting temperature of more than 103, and a decomposition temperature of more than 271. The temperature range available for molding is wide, and the temperature requirement is low, so it has good thermoplastic. Heating and melting at 1:00 does not affect the transparency of the color of polymethyl methacrylate resin and the inherent characteristics of mechanical parts, such as eyelash 2. Therefore, polymethyl methacrylate is solidified into a bar by using hot injection molding to make a Yi1 base. Hot pressing injection molding is a molding method of injection and molding, also known as injection molding. Using the thermal plasticity of the resin, the polymer particles are put into the barrel of the injection molding machine, After heating, compression, mixing and transportation as secondary molecular materials, homogenization and melting make the tree boat melt at high temperature with fluidity. This process is plasticization, and then pressure is applied to the melted polymer melt with the help of the screw. Then the high-temperature melt is injected into the mold cavity of the pre ⑷ low-temperature box through the nozzle in front of the barrel and the pouring of the box. After cooling and shaping, the box is opened and the required denture products are taken out. Polymethyl methacrylate and other resins do not have high requirements for molding equipment. As long as the amount of base material used in common plunger injection molding machines and screw injection molding machines does not exceed * 780 of large injection volume, they can be processed in the hall Bian plastic. 1 materials and methods 1.1 basic principle: the cavity is prefabricated in the mold, that is, denture wax gypsum is embedded and washed wax. The mold box is placed on the special base of the dental resin molding machine, and the methyl methacrylate particles in the barrel are injected into the mold cavity under high pressure after heating and melting to obtain the required denture. The compressive strength of ordinary calcined gypsum is 1. The anti-jamming strength of super hard gypsum can reach the injection pressure required by Dengshi general dental tree tire plastic particles is not more than 3 After the gypsum at this place is mixed with water powder ratio and embedded and waxed according to the requirements, its compressive strength is enough to resist the injection pressure without deformation, Moreover, the continuous pressure of injection molding can compensate for the thermal shrinkage, so that the denture base has a higher suitability. 1.2 composition and structural characteristics dental resin base hot pressing injection molding machine is composed of press parts, hydraulic parts and Tun control parts. press parts, machine seat components, frame components, mold cylinder components, injection components and barrel components. hydraulic components, power components, actuator components and oil tank components. electrical control component container assembly. 1.2.2 structural features of the tuyere control assembly and starting assembly the machine is operated by semi-automatic control. place the mold box on the mold closing cylinder and press the mold closing button to automatically close the mold. Because the docking design of nozzle and mold box is adopted, the nozzle automatically aligns with the sprue opening of the mold box at the same time of mold closing. the feeding is also completed automatically. When the barrel reaches a fixed temperature, press the screw back button, and the granular material will automatically complete the feeding with the screw up and down. in order to prevent the damage of the box cavity caused by misoperation, it is specially designed that the injection can be completed only when the temperature of the barrel section reaches the set temperature, that is, the materials in the barrel are in the molten state, the injection signal light is on, and the injection button is pressed. 1.3 the main technical parameters of dental resin molding machine 66 must be 7.00 elbow injection pressure 160001 clamping force each elbow injection weight 358 * large heating temperature molding area 50 mold diameter 1 screw diameter 2.1 1.4 development of special type box since the clamping pressure * of hot pressing injection molding is as high as 16000, the traditional type life cannot meet the requirements of injection molding regardless of its external shape and compression resistance. Therefore, a special type box is designed. The type box is made of metal. The sprue opening of the type box cover is a semicircular groove design corresponding to the barrel nozzle, which can automatically make the type box closely correspond to the nozzle during clamping, so as to prevent material escape during injection. Relevant technical parameters charge box mold cavity pouring diameter 8 box shuttle cavity burning path depth 20 stomach mold box diameter 20 * large molding area 1.5 operation process 1 conventional mold taking, embedding, wax removal, mold box insulation 4600 turn on the segment, the material merchant heating power supply segment, the barrel temperature display reaches the positioning barrel feeding, turn on the pump, mold closing, adjust the injection pressure and mold closing pressure, screw back to the barrel, feed and place the mold box in the base model, and the feed back temperature of the dynamic positioning segment of the box reaches the set value from small to small injection signal When the light is on, injection Baole mold opening 1.6 precautions for operation 16.1 plastic particles need to be dried in the drying oven before injection molding 2 6.2 type box shall be placed in the oven for 51 standby after wax removal. 163 it is necessary to withdraw the screw feeding only when the temperature of the segment barrel reaches the set value, otherwise the screw will break and scrap the mold. Before injection, use a blowtorch to heat the sprue orifice and injection nozzle to prevent the material from forming and the injection fails. 1.6.5 after injection, the molding box shall be kept at a pressure of more than 1, and the products shall be carefully unpacked after natural cooling and complete curing. Results the preliminary application of this model results 2.1 this machine has good operability, and the complete denture base is successfully made without deformation. 2.2 the cavity is fully filled, and the base plate is well combined with the plastic teeth by visual inspection. 2.3 gypsum and products are easy to separate and have good demoulding property. 2.4 visually observe that the base has no bubbles, the surface is smooth, and it is easy to grind, modify and polish. 3 discussion 3.1 the traditional molding method of denture plastic base, that is, the water powder mixing heating curing molding method, heating polymerization, has been used for nearly 70 years. The molding process has the advantages of simple equipment, easy operation, low requirements for gypsum, but the denture base made by acrylate resin water bath method is not completely satisfactory, and has its inherent shortcomings, such as residual monomers and bubbles in the base. It affects the anti music strength of the base and stimulates the polymerization and temperature shrinkage of the oral adhesive base, so that the shrinkage and deformation of the base are large, and the deflection and bending strength are small. Its bending strength is even equivalent to that of the normal temperature curing base. The base is easy to age, and the water absorption is large. Over the years, many scholars have been pursuing the improvement and development of the curing technology of denture resin base. 13.2 injection molding is an early molding method for plastic processing. With the rapid development of plastic, the continuous introduction of new high-grade materials and engineering plastics, and the desire to replace steel with plastic and other non-metallic materials is gradually realized. The dental industry is also exploring the use of injection molding method to form poly (methyl endo-1-enoic acid) reinforced polycarbonate resin. The thermal continuous reporting process of thermosol injection polysulfone resin is called denture base. It has been applied in clinic. 1 at present, most injection molding materials in Yiyang Dituo village are still mixed with water powder and then molded, and then heated and solidified under pressure, including 58% with clothing substitutes. 3. Continuous injection of Leyi mat curing system 1. The injection molding system designed generally believes that this kind of injection molded base has better accuracy and mechanical properties than the traditional water bath. The principle of an alternative injection molding system in the real sense is to directly use plastic particles to heat and melt and then inject under pressure. In the wood United States and our Xiangjun 3000 system, there are many clinical developments. The research results of the products are clear. As a denture base, Its biocompatibility, mechanical and physical properties, residual monomers and water absorption have been greatly improved. 7 huandengmei recessive denture, which is still in use at present, has been greatly improved. I have carried out less research, and the research is very unsystematic, and there is no literature report. 3.3 this model is suitable for direct injection molding after heating with polymer plastic particles. Compared with the Japanese system, this model has obvious price advantages. This model, which is only one-third of the phase 1 function, is characterized by a wide range of adaptability, a wide range of temperature and injection pressure control, up to 400 and off respectively, and can meet the injection molding of most high-grade shoemaker hammer materials, such as polymethyl methacrylate, polycarbonate, polysulfone, etc. It can also be compatible with the injection molding and manufacturing hook of invisible denture. 1 compared with this model, the outstanding difference of this model lies in the design and control of the box. In order to prevent the box from thickening and deformation due to the separation of injection pressure, this model has a huge clamping force between the boxes * 16000 This model has multiple semi-automatic operations. When the temperature and pressure reach the set value, the heating and pressurization will be automatically stopped and feedback control will be carried out. Moreover, the injection button can be effectively started only after the conditions that all the segment barrels reach the set value are met, so as to prevent misoperation and avoid damaging the device of mechanical heart components such as screw barrels. In addition, the injection molding equipment of this machine can reach 37 people, which can fully meet the injection molding volume requirements of clinical complete denture occlusal pads and other restoration products. The large and bulky size of the whole machine is the focus of this model that needs to be improved. The denture products and related test pieces were preliminarily trial produced with polymethyl methacrylate resin on this machine. The current results show that the products have no visible bubbles with the naked eye. Compared with the traditional curing method, the residual methyl methacrylate monomer is less and the texture is harder. After the fixed treatment, the base plate is well combined with the resin teeth. Relevant experimental research is still in progress. After the successful development of this machine, we can conduct research on the denture bracket and other products. Explore the dental injection molding process. Wang Xingtian, chief editor, injection molding technology, chemical industry press, 1993 edition, chenzhiqing, chief editor, oral materials, people's Health Press, 1995 edition 42 7. See Gao Zhi from time to time. Thermal plasticity アクリシシクシシッ0 denture bed materials t レシッ t the first full organization process academic conference solicitation notice organizational engineering research has developed rapidly in China in recent years, and the basic scientific issues project of tissue engineering with Professor Cao Yilin as the chief scientist has been included in the 973 project of the national key basic research and development plan. In order to widely exchange new research results in the field of tissue engineering research in China. Progress has promoted the development of domestic tissue engineering research. The tissue engineering group of the restoration and reconstruction surgery committee of the Chinese Rehabilitation Medicine Association and the biomaterials branch of the Chinese society of biomedical engineering plan to jointly hold the th National tissue engineering academic conference in Guangzhou in December of 2. We hereby notify the following about the solicitation of papers. 1 Seed cell research includes 1 embryonic stem cells; 2 bone marrow stromal stem cells; 3 allogeneic cells; Research on the law and mechanism of cell aging and the prevention of aging. 5. Extracellular culture and amplification technology 2. Research on biomaterials with tissue engineering as the application background, including 1. Research and development of new biomaterials; 2. Research on biocompatibility of materials; 3. Research on the affinity between materials and cells, research on tissue engineering technology, research on the construction of tissues and organs, and Research on related technologies related to tissue engineering. It is required to solicit papers from researchers engaged in basic research of tissue engineering, biomaterial research and clinical application all over the country. Please send the full text of the thesis and 50 word abstract with 35 inch floppy disk to Professor peiguoxian 1, Department of traumatic orthopaedics, Nanfang Hospital, Guangzhou Second Military Medical University, postcode 51515, before September 3, 2002 Please affix your official seal to the manuscript. The tissue engineering group of the Chinese Commission of repair and reconstruction surgery will hold the characterization meeting of mechanical properties of biomaterials and metals of the Chinese society of Biomedical Engineering 200q4.24

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