Craft of SMC mould pressing is a kind of advanced composite material shapes means, and the foundation that the mould is SMC craft, good product quality is assured by reliable mould. Because this is in the design work of craft of SMC mould pressing, the design of the mould is attached most importance to especially should. In SMC mould pressing instrument provides a design in the process, should design a pattern according to the specific measure of the product model antrum. Ask to choose right stuff with demand size according to the exterior quality of the product even besides. To assure the quality of the product and craft feasibility, should of reasonable design mould cut edge, top to give a system to wait. 1, of cent face design is a product easily drawing of patterns, assure the element such as product precision, intensity and facilitating mould treatment, the choice of cent face should consider following principles: ① is rolled out to make the product facilitates, simplify the top gives an orgnaization, after the position of cent face should make the product is flying a model, stay as far as possible in lower mould; ② reduces the flash harm to product exterior as far as possible, should facilitate at the same time the flash of cleared remains; ③ facilitates the mould is made reach treatment of mould spare parts; The product with high demand of precision of ④ radial dimension, should consider the flash ply impact to product precision, take perpendicular cent face to facilitate assure product radial precision; ⑤ assures the intensity of the product, avoid horn of product occurrence needle and Bao Bi. The design of cent face is very important, initial stage should be designed to undertake cent design to the product in the mould, the picture gives cent design blueprint, ensure the product can be successful drawing of patterns and facilitating production. 2, precision of treatment of new pattern of of treatment precision requirement basically has 3 sides: Dimension public errand, form tolerancepublic errand and exterior surface roughness. The treatment precision requirement that we raise to die manufacturer normally basically is dimension public errand and exterior surface roughness. Dimension public errand divides roughly again for: Over all dimension and modular antrum dimension. Two kinds ask to compare to mould over all dimension comfortable, on size error of theory of blueprint of effective treatment dimension and mould does not exceed ±1.5mm to calculate qualification. Precision of dimension of range pattern antrum asks that he must be controlled strictly by blueprint, do not exceed 0~0.1mm commonly. The mould surface precision that we say points to exterior surface roughness commonly, coarse of general requirement mould antrum spends processing hind for 0.4, the others is 12.5. The mould surface that we can ask to put forward to answer relatively according to real product surface machines precision. 3, rake of 3.1 drawing of patterns designs of mould design because produces systole after SMC goods is cooling, can make the product encases mould core is mixed closely model the raised part in antrum. Take out a product smoothly to facilitate, when preventing drawing of patterns, be contused or abrade product, when designing SMC product, direction of drawing of patterns of edge of face of the appearance inside its all should have rake of enough drawing of patterns. When the design, should notice the following two respects: ① mould pressing shapes when older SMC product, the rake of drawing of patterns of the surface inside the requirement is more than the rake of drawing of patterns of outside face; Value of rake of ② commonly used drawing of patterns is spent for 1~1.5, also but small go to 0.5 degrees. 3.2 cutting what the edge designs pattern to cut a margin is fluctuation model mutual and occlusive part, general requirement uses blaze to quench. In process of SMC mould pressing, cutting what what place between the edge is the Mao Bian of the product. Mao Bian is useless part to the product, from the clearance that the mould cuts a margin for this can a few bigger. But cut an edge to be caused easily greatly too run makings and discharge are pressed, this can be solved through adjusting the height that cuts a margin, cut in the design namely from time to tome two require design and adjustable element, cut the clearance of the edge and the height that cut a margin. Cutting a margin is one of factors with mould main design, the size that cuts a margin is direct affect a product whether shape and whether does blemish exist when the product shapes, because this answers its,ask strictly and control. Particular case sees a table 1. Goods of material of moulding of of design of 3.3 round horn besides use afore-mentioned requirements to use pointed part besides place, all corner are in the others to all answer to transfer in order to have circular arc. Product pointed part is in concentration of easy generation stress, burst produces in the meeting when get power or pounding vibration, split easily in process of drawing of patterns as a result of suppress internal stress even, affect product strength. Usually, use round horn radius to be able to make for 0.5mm product strength increases greatly. The good point that uses round part basically has two sides: ① prevents stress concentration, raised product strength to reach beautiful; ② mould does not send because of stress concentration craze when quench and be used. 3.4 heat the temperature of the affirmatory mould of means affects product directly shape quality and manufacturing efficiency, so the need on the mould is added heat the system asks with reaching ideal temperature. Heat systematic cent heats for report, steam heats reach oil to heat. Report heats to heat commonly usedly means, its advantage is equipment simple, compact, investment is little, facilitating installation, maintenance, use, temperature adjusts easily, easily automata; Steam heats, heat fast, temperature is evener, but not easy control, charge heats relative to report taller; Oil heats, temperature is stabilized equably, heat fast, but have pollution to working environment. Choose to new pattern why to plant heat means, can reach pitch of mould size, model according to each company existence condition the factor such as complex degree is certain. The choice of 3.5 finishing to raise a pattern exterior wearability is mixed be able to bear or endure corrode sex, often undertake proper finishing to its. Mould plating chromium is the finishing method with a kind of much application. Plating chromic layer has strong passivation capacity in atmosphere, can maintain metallic burnish for a long time, all do not produce chemical reaction in a variety of acidity medium. Film hardness amounts to 1000HV to be equivalent to HRC65, have admirable wearability consequently. Plating chromic layer still has taller hear resistance, heat in air 500 when spending, its exterior and hardness still do not have apparent change.
The design of the mould in craft of mould pressing of SMC of glass reinforced plastics wants a place
