Precision casting one of the more commonly used investment casting, also known as lost wax casting: selection of suitable investment casting materials (such as paraffin) made investment casting; repeat dip in investment casting refractory coating refractory and sprinkle sand step hardening shell and dry; then melt inside the mold to melt away, get cavities; baked shell with sufficient strength, and the burned remnants of melt molding materials; casting metal material required; solidification cooling, after shelling sand, to obtain a high-precision product. Depending on the product needs or heat treatment and cold working and surface treatment. Such as sand casting, mass production of the factory should create conditions for the use of advanced modeling techniques, making the core methods. Old style shock or shock compression molding machine production line productivity is not high enough, big labor intensity, noise, not suited for mass production requirements, should gradually be transformed. For small castings can be used horizontally or vertically parting parting flaskless high-pressure molding machine production line, real modeling and high production efficiency, the area is also less; for the member can choose a variety of high-pressure molding machine has a box production line, gas impact molding line to adapt to rapid, high-precision molding production line requirements, making the core methods can be used: cold-box, hot-box, such as efficient core-shell core methods.
Moderate quantities of large castings can consider applying resin self-hardening sand molding and core making.
Single and small batch production of heavy castings, hand modeling is still an important way to adapt to a variety of hand-modeling complex requirements more flexible and does not require a lot of technical equipment. You can use water glass sand, VRH law water glass sand, organic ester water glass self-hardening sand, dry clay, sand and cement self-hardening resin sand and the like; for single-piece production of heavy castings, pit modeling method using low cost, production fast. Long-term production batch or multi-box styling products styling, split box modeling method is more appropriate, although mold, sand boxes and other start investment high, but can be compensated from saving modeling time, improve product quality.
Low-pressure casting, die casting, centrifugal casting and other casting methods, equipment and tooling for the expensive, so only suitable for mass production.
The method should be suitable for the conditions
For example, it is also producing large castings, machine bed, the general set of core modeling method, without creating the appearance and sand box, in the ground pit group core; another factory sand box modeling method is used, the production looks like. Different production conditions (including equipment, space, staff quality, etc.), production habits, the experience gained not the same, should be considered for what product and is not suitable (or can not) do what the product according to these conditions.
Accuracy requirements and costs
Precision castings of various casting methods obtained by different initial investment and productivity also inconsistent, and ultimately economic benefits are also differences. Therefore, to do more, faster, better and cheaper, we should take into account all aspects. Casting method chosen to deal with a preliminary cost estimate to determine the high economic efficiency but also to ensure casting casting requirements.
Although China's foundry industry is in a difficult period, but from a long-term perspective, China's industrial development of precision casting still have some hope, market demand has slowly began to pick up, and coupled with China's foundry industry Development has solid strength, I believe our industry foundry industry will achieve gratifying results. |
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