Every polymer shrinks at a different rate. For example, semicrystalline plastics (like Polypropylene) shrink significantly more than amorphous plastics (like ABS). The toolmaker must scale the mold cavity larger than the desired final part to account for this shrinkage. Under ISO 20457, materials are classified into groups based on their shrinkage behavior. 2. Mold Flow Analysis
But six weeks later, after a grueling round of revisions and a landmark experimental study from NIST proving Elara’s math correct, the revised clause passed. Iso 20457 Tg5
The most common tolerance groups for injection molding range from TG3 to TG9. The table below summarizes the typical applications for these groups: Every polymer shrinks at a different rate
Looking ahead, the standard is under active review, with an updated version, , currently in development. In February 2026, the DIS (Draft International Standard) was approved for registration as an FDIS (Final Draft International Standard), indicating that a revised version is expected in the coming months or year. It is advisable to follow these developments closely. Under ISO 20457, materials are classified into groups