![]() The more that are combined, the better the manufacturing efficiency. Many components can be combined into a single casting. Investment casting is a good alternative to weldments or fabricating. Achieving net-shape or near-net-shape cast components can dramatically reduce post-cast processing costs. For example, where machine tools cannot reach. Many of these configurations are impossible to produce. Investment casting provides consistent and repetitive close tolerances along with intricate passages and contours. Most cast parts fall in the ounces to a 20-pound range. This capability is limited to a relatively small number of investment casters and requires special expertise in handling. Final dimensional inspections, alloy test results, and NDT are verified prior to shipment.Īdvantages of Investment Casting Process Size range:Īlthough most investment castings are small, the investment process can produce castings weighing more than 1,000 pounds. Non-destructive testing may include fluorescent penetrant, magnetic particle, radiographic, or other inspections.The gates and runners are cut from the casting, and if necessary, final post-processing sandblasting, grinding, and machining is performed to finish the casting dimensionally.Once the casting has cooled sufficiently, the mold shell is broken away from the casting in a knockout operation.Vacuum melting is utilized mainly when reactive elements are present in the alloy. Either air melting or vacuum melting may be employed as dictated by the alloy chemistry. Nearly any alloy can be produced using this process.The mold is preheated to a specific temperature and filled with molten metal, creating the metal casting.In addition, it helps to minimize the reaction of the shell and metal during pouring. This high-temperature operation also increases the strength and stability of the ceramic material.At this point, the residual wax pattern and gating material have been completely removed and the ceramic mold remains with a cavity in the shape of the desired cast part. Any remaining wax soaked into the ceramic shell is burned out in a furnace.The entire assembly is placed in a steam autoclave to melt away most of the wax.Once the ceramic shell has dried, it becomes sufficiently strong to retain the molten metal during casting.That thickness is partly dictated by product size and configuration. Cycles of wet dipping and subsequent stuccoing are repeated until a shell of the desired thickness is created.The entire wax pattern assembly is dipped in a ceramic slurry, covered with sand stucco, and allowed to dry.Depending on the size and configuration of the desired finish component, multiple wax patterns may be processed using a single tree.Once a wax pattern is produced, it is assembled with other wax components to form the gate and runner metal delivery system.Mounting the Wax Patterns and Creating the Tree Patterns are typically made of wax using a metal injection die.ī.It utilizes a pattern with the same details as the finished part, except that there is an allowance for thermal contraction (i.e.What is investment casting used for? Let’s break down the investment casting production process for a greater understanding: The Investment Casting Process A. The wax pattern is melted and removed in a furnace and metal is poured into the shell to create the casting. ![]() So, What exactly is the investment in “investment” casting? The term “invested” historically carries the meaning of “clothed” or “surrounded.” Investment casting employs a shell made of ceramic, plaster, or plastic that is formed around a wax pattern. The goal is to understand what is meant by investment casting. ![]()
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