Engineering Models

Engineering models are stereolithography parts that are lightly sanded to remove evidence of supports and layering and then honed to provide a matte finish. The primary purpose of an engineering review model is to visually communicate a design to the development team, marketing, and management, customers and tooling vendors.

An engineering model is inexpensive insurance that the design you had in mind is the same design that your management or tooling vendor had in mind.

Functional Prototypes

Stereolithography resins have come a long way in the past few years. While initial SLA resins were brittle and not suited for functional testing, resins are now available in a range of properties and can simulate properties of injection molded plastics. It is now possible to build SLA parts that will predict the performance of injection molded parts. Express Pattern has been a leader in developing this technology

Because stereolithography resins and injection-molded plastics are fundamentally different materials, stereolithography resins never duplicate all the properties of a thermoplastic material. However, for any given prototyping situation, the performance of a plastic component is governed by just a few key material properties. If we choose an SLA resin so that those key properties closely approximate those of the desired injection molded plastic, a part built in that resin will perform very much like the plastic component, even if other material properties are not close. Consequently, the SLA part will allow the user to draw valid conclusions about the viability of the design in the desired plastic material.

Express Pattern has done a great deal of work to identify common prototyping situations and key material properties, and in each situation matched the SLA resins we use to common injection molded plastics. Those prototyping situations are