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.
Understanding what shrink rate is and how it impacts your final product is crucial for ensuring a desired end result.
What is a Material 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.”
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?
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.
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.
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How to Plan for Material Shrink Rates
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. Materials may experience extreme shrinkage that can drastically warp your end result.
As a starting point, review the allowances of your specific material. Omnexus has a reference of high shrinkage materials and low shrinkage materials that’s helpful to reference during the material selection process.
Consulting with a thermoforming professional will help prevent design errors and late-stage product difficulties. Don’t be afraid to inquire about shrink rates when you’re in the early planning stages – the sooner you plan, the better.
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 us and speak with an engineer about your project at (612) 781-2255, or request a quote online. You will receive a prompt response.
Industrial Custom Products is a one-stop-shop for custom manufacturing and plastic fabrication, including: prototyping and product development, die cutting and dieless knife cutting, thermoforming and vacuum forming, large part thermoforming, CNC plastic routing, fabrication and assembly and drape forming.
