Factors such as design requirements, cost, and feasibility to manufacture dictate which casting process is most suitable to manufacture a product. Investment casting produces precise components while minimizing material waste, energy, and subsequent machining. It can also ensure the production of very intricate parts. This makes the investment casting process quite useful to design engineers.
The goal is to understand what is meant by investment 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 wax pattern is melted and removed in a furnace and metal is poured into the shell to create the casting.
Investment casting provides consistent and repetitive close tolerances along with intricate passages and contours. Many of these configurations are impossible to produce. For example, where machine tools cannot reach. Achieving net-shape or near-net-shape cast components can dramatically reduce post-cast processing costs.
Investment casting is a good alternative to weldments or fabricating. Many components can be combined into a single casting. The more that are combined, the better the manufacturing efficiency. Converting multi-piece components to a single investment casting typically delivers more dimensional accuracy and reduced part complexity.
CNC machining is a manufacturing process that utilizes computerized controls to operate and manipulate machine and cutting tools to shape stock material—e.g., metal, plastic, wood, foam, composite, etc.—into custom parts and designs. While the CNC machining process offers various capabilities and operations, the fundamental principles of the process remain largely the same throughout all of them.
Metal stamping is a cold-forming process that makes use of dies and stamping presses to transform sheet metal into different shapes. Pieces of flat sheet metal, typically referred to as blanks, are fed into a sheet metal stamping press that uses a tool and dies surface to form the metal into a new shape. Production facilities and metal fabricators offering stamping services will place the material to be stamped between die sections, where the use of pressure will shape and shear the material into the desired final shape for the product or component.
Forging is a metal working process that manipulates, shapes, deforms, and compresses metal to achieve the desired form, configuration, or appearance outlined by a metal processing design or diagram. Depending on the type of metal and the requirements of the design, the forging process can be completed using either hot or cold forging processes.
Is there any reason to specify powder metallurgy over traditional machining beyond that is how we have always done it? The answer is a definite yes -- and for more reasons than just the low cost.
With conventional manufacturing, you melt it, you roll it, you cast, if you machine it. A lot of steps, and a lot of scrap metal at the end.
Using powder metal reduces waste considerably and therefore can be called an environmentally friendly manufacturing process. Sounds like an oxymoron, but it is really true!
Leftover metal from machining is minimized. There are no metal chips to throw out. When you look closely, it is apparent that powder metallurgy is truly a green process. In fact, a study by Ford Motor Co. a few years ago showed that the PM process is 15% more energy-efficient than traditional machining.
Naturally machining from a solid workpiece is sometimes a requirement. But with many projects, you can avoid secondary machining entirely by using the powder metal process.