TW453918B - A method of precise casting of shell - Google Patents

Abstract

This invention is related to a method of precise casting of shell, comprising the steps of: using polyurethane methyl acid ethyl ester resin foam to make a cast prototype, which goes through multiple dipping and sanding processes so as to form a shell mold of a shell around the outer surface of the prototype after dehydration; and removing the prototype in the shell mold by sintering, such that the shell mold can be injected with high temperature metal to cast various mechanical, metal components.

Description

4539 1 8 V. Description of the invention ⑺ The present invention relates to a thin-shell precision casting method, which is firstly made by using 4-amino-based formic acid + s purpose resin hair% &# > @ μ Γ-a profiling model, and then Through the dipping process: the U step of the operation is completed to complete a thin shell shell mold. # Available for pouring two-temperature metal to cast various mechanical hardware parts. According to the method of dewaxing precision casting used in the industry, China has nearly 15 years of experience in production, but this method still has technically insurmountable bottlenecks for the production of large and complex precision cast corpses. The reason is that when steamed milk is dewaxed, the instantaneous swelling pressure of the wax is very large, and the shell mold must have a considerable thickness in order to withstand this pressure, which also makes the shell mold production speed slower, and it must waste more high prices. Refractory materials and bonding agents, especially when the requirements of castings and dimensional accuracy are high, and the weight of the castings is more than 15 kg, and the large precision castings of less than 200 kg, the dewaxing precision casting method is technically There are difficulties in its implementation, because there is no large supporting equipment (such as large wax injection machine, wax mold, shell and dewaxing equipment, etc.), so the dewaxing precision casting method has been limited to some smaller The casting process of components is also a bottleneck that is difficult to break through in this method. In view of this, and in view of the lack of current dewaxing precision casting methods, the inventors finally completed the thin shell precision casting method of the present invention after numerous tests, and broke through the general dewaxing casting facilities that cannot be large or complicated. The technical bottleneck of component casting. The purpose of the present invention is mainly to provide a technical bottle item that can not be broken by dewaxing casting, especially for the casting of large or complex precision components, which can obtain a casting with better size, stability, low cost and high quality. effect

Page 4 4 5391 a V. Description of Invention (2). The following is a detailed description of the method of the present invention in conjunction with the illustrations below. [Schematic description] The first diagram is a schematic diagram of the process of the present invention. The second diagram is a cross-sectional diagram of the profiling model and mold molding of the present invention. The second diagram It is a schematic cross-sectional view of the profiling model of the present invention. 0 The fourth figure is a cross-sectional schematic view of the shell mold molding of the present invention. The fifth diagram is a cross-sectional schematic view of the shell mold of the present invention. Schematic cross-section view of operation 〇 [Illustration of drawing number] Mold (1) Copy model (2) Shell mold (3) Pouring D (3 1) Outer edge (3 2) Sand box (4) Dry sand (4 1) First j Please refer to the figure --- the flow chart of the method of the present invention. The method step is 1. • Polyurethane resin Scale model made of foam (1) The main components of the raw material of polyurethane amino resin are two main ingredients * polyether polyol 7 0 9 0% \ polypropylene glycol 1 0 3 0%, ammonia catalyst 1 ~ 3 %, Silicone oil 0.3 ~ 1.5%, water 1.0 ~ 3.0%, peroxidant 10 ~ 15%; hardener: phenylmethane diisocyanate NCO2 5 ~ 3 0%. ., 4. 4 'MDI; The mixing ratio of the main agent and the hardener is 1: 1. 2 ~ 1. 3 5;

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4 53 9 1 S $, description of the invention ⑼ 2) Polyurethane resin raw material injection mold (shown in the third picture: After foaming, ^ casting prototyping model (2) is shown in section ^, 2 The shape model (2) is placed in a dip stick I, / Xia Bazhan, hey Jian, dip the mud and then take out the refractory sand, repeat the dip and drench the sand 5 times (depending on the size of the shell mold, the larger the volume, Adding to the paste will increase the second), after drying, a thin shell shell mold (c 篦 4, jade picture; as for the composition of mud refractory sand: silicone i 〇2 30%) 23 · 1 6% 、 Zircon sand powder 53 8 ^ Surfactant 0.02%, Fused silica powder 22, 86%, Elimination of a few drops of 0.03%, Tackifier 0.1%. ^ 3 Sintering treatment: The shell mold (3) is sintered in a heating furnace (the temperature is about 8000), and the mold is burned (2), and then the shell mold (; 3) is taken out; " "4. Casting : The high-temperature molten metal is introduced from the shell mold (3) port (3 1) &main; 5 _ shell removal mold treatment: the molten metal is washed and poured into the shell mold (3), and then cooled and shaken. Machine Shattered Shell The mold (3) can obtain castings. When the inner mold is very light, the shell mold (3) can be placed in the outer edge (3 2) of the sand box (3) and The sand box (4) 'is used as a reinforcement of the positioning and the strength of the shell mold. It can be reused repeatedly.' There is no wave, so in the large-scale casting C4) 'and the dry sand (4) is filled between the shell molds. 1, and this dry sand (41) is precision cast by the casting method of the present invention, and the following better

453 91 8 V. Recording conditions and effects of the description of the invention (4): 1 The surface of the casting made by this method is smooth, and the appearance of the refined product is normal. And it is similar to the stable precision castings of casting size converted by this method. Much higher than one blood 3 'is more flexible for the choice of casting gate. 4 · Can greatly reduce the requirements for waste sand (referring to dry sand). The management cost is in line with environmental protection 5. It is especially suitable for a small number of diverse production strips to effectively reduce. Parts, the cost of the mold can be 6. suitable for complex shapes or medium and large castings. 7. The molding size is stable without shrinkage and deformation. 8_ The casting surface is smooth, the deformation rate is low, and the phenomenon of reserving is reserved. Less, effectively saving reprocessing costs. In summary, the above-mentioned invention can solve the technical bottle neck of general dewaxing precision casting, which can effectively provide higher-quality casting conditions and reduce the cost of casting molds. It is an innovation of the technical means of the present invention and has significant benefits.

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Claims (1)

4 53 9 1 8 VI. Application for patent scope 1. A thin shell precision casting method, the steps are as follows: (1) Polyurethane Ethyl Acetate resin foam is used to make a casting model; (2) Dip slurry Sand operation: Put the contour model into the dipping cylinder, dip the mud and take out the refractory sand, repeat the dipping and sand dipping operation about 2 ~ 5 times, and after drying, complete a thin shell shell mold; ( 3) Sintering process: the shell mold after the slurry is drenched and dried is placed in a heating sintering (temperature is about 800 ° C). 'Remove the contour mold by combustion ^ and then take out the shell mold;' * (4) Casting: The molten metal at a high temperature is injected from the shell mold into the shell mold under low pressure; (5) Shell removal mold treatment: The molten metal is washed and poured into the shell mold, and it is broken by a vibration machine after being installed and shaped. The shell mold can obtain the finished product of the casting ^ Cool to 2 · As described in the first patent application scope of r ~~ Silk # Manufacture method "'wherein the polyurethane resin raw material person #Precision casting soil · Wang Yao ingredients Alcohol% water main agent: polyether polyol 70 ~ 90%, polypropylene 0%, ammonia-based catalyst 1 ~ 3%, silicone oil 0.3 ~ 1] 1 0 ~ 3 · 0%, peroxidant 1 〇 ~ 1 5%;! 〇% hardener: benzyl diisocyanate NC 〇2 δ 4 · 4, MDI; i The mixing ratio of the main agent and the hardener is 1: 1.2 ~ 丄 3 3. As described in the scope of patent application No. 1 "item 5, ° manufacturing method" 'wherein. Polyaminoethyl resin raw material injection' shell precision casting bubble formation A casting profiling model. 'Into the mold, hair 4 53 9 1 8 VI. Scope of patent application 4 · As described in item 1 of the scope of patent application, "a thin shell precision casting method", in which the slurry is refractory sand. The composition is: silicone fluid (including Si ◦ 2 3 0 %) 2 3 .16%, zircon sand powder 5 3 · 8 3%, surfactant 0.02%, fused silica powder 2 2, 8 6%, a few drops of defoamer about 0.03%, 1%。 Tackifier 0.1%. Page 9