Application Overview

Investment casting is a manufacturing process (also known as lost wax casting) where a master pattern (traditionally made of wax) is covered with a ceramic slurry. Preheated wax is then melted out of its ceramic shell before molten metal is poured into it. The process generally provides higher accuracy and surface finish compared to other casting processes and is often used in applications that carry low volume production and changing product designs. 3D printed molds offer greater complexity, substantial time and cost savings when creating wax patterns for prototyping and short production runs.

Application

Wax patterns used in traditional investment casting methods are produced using an injection molding process, with costs ranging from $5,000 – $25,000 and lead times estimating at around two months. A major hindrance for companies is that investment casting foundries are unable to produce prototype castings until the injection mold is completed. 3D printing with FDM technology provides an alternate method for producing investment casting patterns that are a lot more efficient and cost-effective.

3D printing with FDM technology provides an alternate method for producing investment casting patterns that are a lot more efficient and cost-effective. A foundry can produce a pattern that also services as a prototype for form and fit evaluation in a single day, providing a perfect match to the casting that would be produced if that exact pattern were to be used. An FDM part’s durability allows it to be put into an assembly for testing while preventing damage that often occurs in transportation and handling. Due to FDM being an additive process, patterns can be as complex or as simple as needed, without any impact on cost.

Process

The wax patterns used in Investment Casting are produced with an injection molding process. FDM patterns are direct replacements for traditional parts that are injection molded but does not melt like wax. It burns, leaving a small amount of ash in the shell cavity which is then later removed in a shell washing operation. To speed the burnout of the FDM pattern, venting is added to ceramic shells. To prevent defects, patterns need to be produced to close tolerances and with excellent surface finish. Using our expert finishing services, hand finishing is not required on FDM parts, making this method a reliable and strong route in the Investment Casting market.