In the Investment Casting process (also known as the lost wax process), a pattern made in a rapid prototyping machine is coated with a refractory material to make the mold, after which the pattern is melted away prior to pouring the molten metal.  It is a precision casting process because it is capable of making castings of high accuracy and intricate detail.  In addition, metals that are hard to machine or fabricate are good candidates for the investment casting process.  Investment casting is also used to make parts that cannot be produced by normal manufacturing techniques, such as turbine blades that have complex shapes, or airplane parts that have to withstand high temperatures.  At Harvest Technologies, we can supply patterns in either the SLS® CastForm material or the SLA® Quickcast material.  Investment casting is typically the most efficient and economical method for producing metal parts in low quantities.

In the Sand Casting process a mold is created by packing sand slurry around a pattern that then hardens. The mold is pulled away from the pattern and molten metal is poured into the remaining cavity. After cooling and the metal solidifies, the mold is broken and removed from the part. The SLS rapid prototyping system can create a robust pattern in the DuraForm or DuraForm GF material that can work very well in producing multiple sand cast prototypes.  However, sand casting is typically viewed as a production-only process and very few customers use rapid prototyping services for this process.

In the Plaster Casting process a mold is created by pouring plaster slurry, which subsequently hardens, around a rubber pattern that was cast in a silicone tool. The plaster molds are cured, and molten metal is poured into the cavity where it solidifies. Once the cast object has cooled, the plaster mold is broken away and discarded.

These three processes can provide:

. Functional parts and prototypes with good detail and dimensional tolerance.
. A wide variety of ferrous and non-ferrous metals and alloys.
. Can be post-machined for better accuracy, detail and finishing.
. Delivery of part(s) usually in 2 - 4 weeks.