Additive technologies (3D printing) in Investment Casting
Casting process is one of the oldest and first industrial process developed by humans to produce components and are still been in practice since thousands of years. The output can yield detailed, intricate and complex results. During the olden days one of the first materials humans tried for the casting process was bees wax.
Since the bee wax and forms of the bees was ubiquitous in those days it was used as patterns for producing intricate structures for the stunning gold jewelry.
Additive technologies can be utilized for investment casting patterns.Additive technologies in investment casting involves 3D printing of the wax pattern wherein the traditional method uses an injection mold manufactured using subtractive technologyto produce the wax pattern.Rapid 3D Technologies located at Ganapathy, Coimbatore, India is engaged in working with various foundries to develop such 3D printed wax patterns using special wax like plastic material. One of the modern applications for additive casting patterns is creating environmentally friendly and socially conscious jewelry. On the other end of the spectrum, applications for casting patterns have produced products that contain a variety of metals and can weigh several hundred pounds. Additivelygenerated patterns can be created from thermoplastic extrusion using wax, plastics, 3D printing and inkjet technology that utilize wax-like plastics. These types of materials require being melted or burned very cleanly from the investment.
Patterns created from these processes can be any size and range from tiny to several meters. These patterns are introduced in to the ceramic slurry to form a thick coating or investing to the shape of the pattern. A gate can be built into the pattern for allowing liquid materials to be poured into the mold. Passageways can be created to allow for hot air and melted and burned pattern materials to escape. Invested patterns can be placed into a furnace to be fired. This allows burn out or the pattern to a solid, hollow mold. At this point, molten metal can be poured into the ceramic mold and after the liquid metal cools and becomes solid, the mold can be broken, revealing the desired object. Excess material needs to be removed and the object will usually require substantial cleaning.