In the process of injection molding, some product defects often occur. In this article, we will explore 15 of the most common defects that occur in Proe/Creo injection molding products and provide solutions to help you avoid them.
- Short Shots
Short shots occur when the mold doesn’t completely fill with resin. This results in a part that is incomplete or undersized. To prevent short shots, you need to increase the injection pressure or reduce the injection speed. - Burn Marks
Burn marks occur when the resin overheats and burns. This can happen due to high temperatures or prolonged residence time. To avoid burn marks, reduce the melt temperature or increase the cooling time. - Flash
Flash is excess plastic material that protrudes from the parting line of the mold. It occurs when the mold plates are misaligned or the clamping force is insufficient. To prevent flash, adjust the mold plates and increase the clamping force. - Sink Marks
Sink marks occur when the surface of the part sinks inward due to insufficient cooling or filling. To avoid sink marks, increase the cooling time or reduce the gate size. - Warpage
Warpage is when the part becomes distorted or twisted after molding. This can be caused by uneven cooling or excessive shrinkage. To prevent warpage, use a uniform cooling system or adjust the gate location. - Voids
Voids are air pockets that form inside the part. They happen when the resin doesn’t completely fill the mold or when trapped air isn’t properly vented. To avoid voids, increase the injection pressure or use a better venting system. - Flow Lines
Flow lines are visible lines on the surface of the part. They occur when the resin cools too quickly or when there is a change in the flow direction. To prevent flow lines, increase the mold temperature or adjust the gate location. - Weld Lines
Weld lines occur when two or more flows of resin meet and don’t fully merge. This results in a visible line on the surface of the part. To prevent weld lines, increase the injection speed or use a higher mold temperature. - Splay
Splay is a whitish discoloration on the surface of the part. It happens when the resin is contaminated with moisture or when the resin is overheated. To prevent splay, dry the resin thoroughly or reduce the melt temperature. - Jetting
Jetting is a visible stream of resin that appears on the surface of the part. It occurs when the resin flow is obstructed or when the gate is too small. To prevent jetting, increase the gate size or polish the gate area. - Burned Edges
Burned edges occur when the resin is overheated and burned at the edge of the part. This can happen when the mold temperature is too high or when the cycle time is too long. To prevent burned edges, reduce the mold temperature or shorten the cycle time. - Sticking
Sticking occurs when the part doesn’t release from the mold. This can be caused by residual gas or a lack of mold release agent. To prevent sticking, use a mold release agent or increase the venting system. - Degradation
Degradation is when the resin breaks down due to exposure to heat or UV light. This can happen during storage or molding. To prevent degradation, store the resin properly or use a UV stabilizer. - Filling Imbalance
Filling imbalance occurs when the resin doesn’t fill the mold uniformly. This can be caused by uneven pressure or flow. To prevent filling imbalance, adjust the gate size or use a uniform pressure system. - Gating Voids
Gating voids are air pockets that form around the gate area. This can happen when there is insufficient venting or when the gate size is too small. To prevent gating voids, increase the venting system or enlarge the gate size.
By understanding these common defects and their solutions, you can improve your injection molding process and produce high-quality parts. At JS Precision, we specialize in injection molding and can provide expert advice and solutions for your manufacturing needs. Contact us today to learn more.