ENGINEERING MATERIALS GUIDE

A Guide to Elastomeric Materials

From soft-touch grips to durable seals, flexible materials are essential. This guide compares the key rubber-like materials we offer: TPU, TPE, and Silicone.

What is an Elastomer?

An elastomer is a polymer with viscosity and elasticity—properties that give it a "rubber-like" feel. They are defined by their ability to be significantly deformed under stress and then return to their original shape once the stress is removed. Their hardness is measured on the Shore Durometer scale (typically Shore A).

In manufacturing, we primarily work with two types: **Thermoplastic Elastomers (TPEs)**, which can be melted and re-molded like plastics, and **Thermoset Elastomers**, which are cured into a solid state and cannot be re-melted.

A flexible 3D printed shoe sole, a prime example of an elastomeric application

Comparing Flexible Materials

TPE (Thermoplastic Elastomer)

A broad family of rubber-like materials that can be processed like thermoplastics. TPEs are cost-effective and excellent for overmolding onto other plastics (like ABS and PP) to create soft-touch grips. They have good flexibility but average temperature and chemical resistance.

TPU (Thermoplastic Polyurethane)

A high-performance subset of TPE. TPU offers superior durability, abrasion resistance, and tear strength compared to standard TPEs. It's an excellent choice for dynamic applications like wheels, belts, and protective sleeves. It can be 3D printed via SLS/MJF.

Silicone (LSR)

Liquid Silicone Rubber (LSR) is a high-performance thermoset elastomer. It offers the best performance at extreme temperatures (both hot and cold), is UV resistant, and is often biocompatible and food-safe. It's the top choice for medical seals, kitchenware, and outdoor applications.

Elastomer FAQ

Which material is best for a soft grip on a handle?

For overmolding a soft grip onto a rigid plastic handle (like ABS or PP), TPE is the most common and cost-effective choice. It forms a strong chemical bond and provides excellent tactile feel. TPU is a good option for a more durable, abrasion-resistant grip.

I need a flexible part for a medical device. What should I use?

For medical applications, especially those requiring sterilization or skin contact, medical-grade Liquid Silicone Rubber (LSR) is the industry standard due to its excellent biocompatibility and stability. Some medical-grade TPUs are also available for specific applications.

Can I 3D print a prototype before I commit to molding?

Absolutely. We can 3D print your design using flexible TPU via SLS or MJF. This is an excellent way to test the form, fit, and flexibility of your design before investing in an injection mold tool for TPE, TPU, or LSR.