Planning for Material Shrink Rates for Thermoformed Parts

Tuesday, March 23, 2021

When you’re planning your plastic projects and designs, you need to take everything into account from prices and materials to aesthetics and marketability. But truly understanding the nuance of each of these facets can be overwhelming in a fast-paced marketplace. Some details such as shrink rates may seem trivial to consider as you work through your designs, but in thermoforming, even the smallest details can have a big impact on the final results. At Industrial Custom Products, we work to help designers and project managers make the best decisions possible during their manufacturing process, and that means making sure that every detail is accounted for.


What Is a “Shrink Rate?”

True to its name, a shrink rate is “the amount of shrinkage (or contraction) various materials experience when heat is applied to them.” During the high temperatures of the thermoforming process, the materials you use expand and become malleable, then they contract and shrink during the cooling process. For some materials, this shrinking and contracting phase continues even after they’ve been cooled and removed from their molds. Different materials may experience different levels of shrinkage, and thus, have different shrink rates that must be taken into account.


How Do Shrink Rates Impact Thermoforming?

Predicting a material’s shrink rate is an essential part of the thermoforming process. If incorrectly calculated, you may find yourself with products that do not live up to their original design. Shrinking and warping that is not properly accounted for can affect the end-product—from cohesive aesthetic designs to failure points and basic functionality. For instance, delicate parts that fit neatly together may no longer match or intersect seamlessly if one or more of the used materials has shrunk beyond the expected dimensions.


Which Materials Are Impacted?

Because of the variability of shrink rates, it’s essential to work with thermoforming professionals who are familiar with the potential warping of various materials. For example, ABS (acrylonitrile butadiene styrene) may experience shrinkage anywhere from .30% to 1.60%, depending on the type of ABS employed. Reviewing these allowances and consulting with a thermoforming professional can help prevent design errors and late-stage product difficulties. While familiarity with some of the materials we provide is helpful, don’t be afraid to inquire about shrink rates when you’re in the early planning stages.


If you’re in need of thermoforming assistance, are interested in investigating the materials we offer, or have other questions about shrink rates, you can contact Industrial Custom Products; our professionals are waiting to hear from you. Reach out today by calling (612) 781-2255 or by visiting our website here for additional information.