Good Dimensional Stability

Dimensionally stable plastics for tight tolerance applications

Applications that require tight tolerances should look to dimensionally stable plastics with a low coefficient of thermal expansion (CTE), low moisture absorption, and the ability to maintain shape under expected operating conditions. These factors are especially important for precision plastic parts, machined components, fixtures, insulators, and parts that must fit with mating metal components.

Dimensional stability can be affected by temperature changes, moisture exposure, chemical exposure, residual stress, creep strain, part design, and machining practices. If the environment includes chemicals, the plastic must resist swelling when exposed to those chemicals. Moisture absorption can also affect material performance and part dimensions, and Curbell’s nylon vs. acetal material comparison explains how two common engineering plastics differ. If the part is under mechanical stress, the plastic must have sufficient creep resistance to maintain its shape under load for long periods of time.

Use this page as a starting point to compare dimensionally stable plastics for tight tolerance applications, then compare material data in the Plastic Properties Table, review plastics for challenging operating environments, ask a plastics expert for help with your application, or request a quote.

Curbell Plastics can help you:

• Compare dimensionally stable plastics for low CTE, low moisture absorption, creep resistance, chemical exposure, and tight tolerance applications.
• Evaluate material options for machined plastic parts, precision components, fixtures, insulators, mating metal parts, and long-term load conditions.
• Identify plastic materials to consider for your application, operating environment, part geometry, tolerance requirements, fabrication process, and documentation needs.