December 2003 Design Tip

The right resin is a material choice.

Application-specific requirements will always drive the need for particular material properties like tensile strength, impact resistance or ductility.

But successful designs for injection moulded parts are also built on an understanding of process-related issues such as the ability to fill the mould, tendency to flash, ease of part ejection, and the potential for warp, sink or void creation. As noted in prior Design Tips, part geometry can be used to help address some of these issues, but just as material properties are an important factor in meeting the requirements of a given application, they should also be considered to ensure the mouldability of the part.

Table 1 lists some commonly used resins along with their brand names and a high-level summary of their material properties, mouldability characteristics and relative costs.

The complete list of available resins is available on the Protomold web site, and you can visit the Protomold Design Guide for other helpful design information.

Table 1 - Resin Selection Guide