How to Eliminate Distortion from Plastic and Mold Shrinkage Rates?

Plastics Shrinkage Rate & Mold Shrinkage Rate

Understanding plastics and mold shrinkage rates is essential for accurate product design and efficient manufacturing. Each plastic material behaves differently during the molding process, so designers must factor in the shrinkage rate to ensure the final product matches the intended dimensions.

At DSW, we provide a comprehensive shrinkage rate chart for the most commonly used plastics. This helps designers verify their calculations when preparing designs for mold manufacturing. Additionally, our team offers expert guidance to help you select the best materials for your project, ensuring quality results every time.

Importance of Plastics Shrinkage Rate

Plastics shrinkage rate refers to the percentage of size reduction a part experiences as it cools and solidifies after injection molding. Designers must account for this shrinkage to avoid issues like improper fitting, dimensional inaccuracies, or warping.

Shrinkage rates can vary significantly between materials:

• Low-density polyethylene (LDPE) has a higher shrinkage rate (up to 2.0%) compared to more rigid plastics like PVC, which has a much lower rate (0.4%).
• The addition of materials like glass fiber (GF) can also influence shrinkage. For example, adding 30% GF to polypropylene (PP) reduces its shrinkage from 1.8% to as low as 0.4%, improving dimensional stability.

Understanding these differences is key to creating products that meet both design and functional requirements.

Plastics Shrinkage Rate

Mold Shrinkage Rate and Its Impact

The mold shrinkage rate refers to the shrinkage that occurs within the mold cavity as the material cools. This rate directly corresponds to the plastic’s shrinkage rate and plays a critical role in determining the final size of the molded product. Manufacturers use this data to design molds that accurately produce parts with the desired dimensions.

DSW’s mold design and engineering team works closely with customers to ensure the mold shrinkage rate aligns with the material’s properties. This guarantees accurate, high-quality final products and minimizes the need for costly rework. Our expertise helps optimize the entire manufacturing process, from concept to production.

Practical Application of Shrinkage Rates

For example, when designing a part using PVC, which has a shrinkage rate of 0.4%, you’ll need to adjust the mold size to ensure the final part matches the intended dimensions. When working with glass fiber-reinforced materials, such as 30% GF polypropylene (which has a reduced shrinkage rate), mold calculations must account for this lower rate to avoid issues like product misalignment or dimensional inaccuracies.

Using accurate calculations and insight, our team at DSW can guide your material selection and mold design process to ensure that everything runs smoothly and your final product meets your exact specifications.

Mold Shrinkage Rate

Partner with DSW

At DSW, we bring years of experience in mold design and manufacturing. Our team is committed to ensuring that your product performs as intended, from initial concept through final production. We offer personalized consultations to help you select the right materials, calculate shrinkage rates, and design molds that deliver the best possible results for your project.

If you need assistance with plastics or mold shrinkage rates or have any questions about material selection, don’t hesitate to contact us. We’re here to ensure your project’s success from start to finish.