Company Profile
Expert team
Environment
Plastic Raw Materials
Plastic Products
Dyeing Process
Plastic Molds
Company News
Case Sharing
Material Knowledge
Industry News
Comprehensive Information
Customization Process
Core Competence
Material Encyclopedia
Issues with Cracking in PC Parts and TPE/TPR Overmolding Solutions
Time of issue:2024-10-23
Issues with Cracking in PC Parts and TPE/TPR Overmolding Solutions:
Those familiar with engineering plastics will recognize that cracking in PC (polycarbonate) parts is a common issue. The propensity for PC parts to crack primarily stems from internal stresses developed during the manufacturing process. During molding, PC material experiences forced molecular orientation, but due to the presence of inflexible aromatic ring structures, molecular deorientation becomes challenging after cooling.
If deorientation is not properly managed during the molding process—such as through low mold temperatures, insufficient holding pressure times, or inadequate cooling—the molecules cannot relax and deorient sufficiently, leading to internal stress in the final product. When these internal stresses reach a critical level (greater than the force required to initiate cracking), the PC part will develop cracks.
When TPE (thermoplastic elastomer) or TPR (thermoplastic rubber) are used for overmolding on PC parts, the existing internal stresses within the PC can exacerbate the situation. Additionally, if the area covered by the TPE layer is large and the PC part is thin, the contraction of the TPE layer during overmolding can intensify the effect of the internal stresses, causing the PC part to crack.
Solution: When molding PC parts, use high mold temperatures, extend holding and cooling times appropriately to minimize or eliminate internal stresses.
Another issue arises with cracking in the TPE/TPR overmolded layer. This type of cracking typically appears some time after the overmolding process has been completed. The cause of cracking in TPE/TPR layers is often due to poor aging resistance, which leads to material degradation over time.
Solution: Use TPE/TPR grades with better aging resistance to improve the material’s ability to withstand cracking due to aging.
2025 Chinese New Year Holiday Notice
Subo company participated in DMP 2019 Dongguan International Plastics and Rubber Exhibition
Company Profile
Expert team
Environment
Plastic Raw Materials
Plastic Products
Dyeing Process
Plastic Molds
Company News
Case Sharing
Material Knowledge
Industry News
Comprehensive Information
Customization Process
Core Competence
Material Encyclopedia
Our website uses cookies and similar technologies to personalize the advertising shown to you and to help you get the best experience on our website. For more information, see our Privacy & Cookie Policy
Our website uses cookies and similar technologies to personalize the advertising shown to you and to help you get the best experience on our website. For more information, see our Privacy & Cookie Policy
These cookies are necessary for basic functions such as payment. Standard cookies cannot be turned off and do not store any of your information.
These cookies collect information, such as how many people are using our site or which pages are popular, to help us improve the customer experience. Turning these cookies off will mean we can't collect information to improve your experience.
These cookies enable the website to provide enhanced functionality and personalization. They may be set by us or by third-party providers whose services we have added to our pages. If you do not allow these cookies, some or all of these services may not function properly.
These cookies help us understand what you are interested in so that we can show you relevant advertising on other websites. Turning these cookies off will mean we are unable to show you any personalized advertising.
Privacy Policy
TEL: +86-0752-6768128 FAX: +86-0752-6768088 MAIL: sales@tpe-sp.com WEB: en.tpe-sp.com
ADD: Huangxi Industrial Park, Shiwan Town, Boluo County, Huizhou City, Guangdong Province，China
