How to Fix Injection Molding Defects
Common Injection Molding Defects and Their Causes & Solutions
In the production of plastic products, the precision of the injection mold plays a critical role in determining product quality and mass production stability. Whether manufacturing automotive components, household appliances, consumer electronics, or medical devices, defects during the injection molding process can lead to increased scrap rates and potentially damage brand reputation.
Article Outline
1. Common Injection Molding Defects and Causes
2. How to Choose A Mold Manufacturer?
3. Prevent Mold Defects at the Source
1. Common Injection Molding Defects and Causes
(1) Sink Marks
Cause
The thickness of the mold’s rib (support structure) is more than half the thickness of the part wall.
Solution
Use mold flow analysis in the early design stage to identify potential sink issues. If unavoidable, modify the part design to reduce wall thickness differences.
(2) Flash
Cause
Poor mold fit or insufficient clamping force during injection.
Solution
Check mold alignment, repair or rework the mold, increase clamping force, or adjust the mold base for better sealing.
(3) Weld Lines
Cause
Melt fronts split and fail to fully fuse during filling.
Solution
Perform mold flow analysis in advance to identify high-risk areas. Change gate locations or injection paths to improve flow convergence.
(4) Splay Marks / Flow Marks / Water Marks
Cause
Excess moisture in the material or uneven heating.
Solution
Thoroughly dry the material and reduce the barrel heating rate.
(5) Burn Marks / Air Traps / Bubbles
Cause
Air gets trapped and overheated under pressure during injection.
Solution
Improve venting, and lower the injection speed and barrel temperature.
(6) Warping / Deformation
Cause
Uneven wall thickness or unbalanced cooling system.
Solution
Use mold flow analysis to optimize part thickness design and improve the cooling system layout.
2. Why Choose UKS MOLD as Your Mold Manufacturer?
As a leading mold manufacturer based in Taiwan, UKS MOLD is renowned for its expertise in precision mold making and customized solutions. We serve global clients across the automotive, consumer electronics, and industrial sectors.
UKS MOLD Services at a Glance:
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Tailor-made mold development for complex parts
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Advanced CNC machining with micron-level accuracy
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Mold flow simulation to reduce trial-and-error
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Global project experience across Latin America, India, the Middle East, Russia, and Africa
Mold Manufacturing: A Fusion of Craftsmanship and Engineering
Creating a high-performance mold requires more than just advanced machines—it demands deep technical knowledge, rich hands-on experience, and seamless team collaboration. Selecting a skilled and experienced mold manufacturer like UKS MOLD ensures not only product quality but also faster time to market and long-term cost efficiency.
At UKS MOLD, every tool we build is engineered for durability, structural accuracy, and high-volume productivity. If you’re looking for a reliable mold manufacturing partner, our team is ready to help. Contact UKS MOLD today to explore how we can support your next project with precision and professionalism.
