WebA gradual change in wall thickness is recommended to avoid any sudden change in the material flow direction. Increase molten plastic temperature during injection molding. … WebCommon defects linked to the processing of the plastic resin in the mold include: Blistering – Bubbles or raised imperfections that are generally caused by too much heat and/or inadequate cooling. Burn marks – …
What Causes Flow Lines in Plastic Injection Molding?
Flow lines are off-color lines, streaks, and other patterns that appear on the surface of a part. These are caused by the shot of molten plastic moving at different speeds throughout the injection mold, which ultimately causes the resin to solidify at different rates. This is often a sign that injection speed and/or … See more Sink marks appear as depressions, dents, or craters in thick sections of a part. Thicker sections take longer to cool, which can have the often unanticipated side effect of the inner … See more What is delamination? Delamination is a condition that causes a part’s surface to separate into thin layers. These layers, which appear like coatings that can be peeled off, are caused by the presence of contaminants in the … See more “Short shots” refer to instances in which the resin doesn’t entirely fill the mold cavity, resulting in incomplete and unusable parts. What causes short shots in injection molding? Typically, they are the result of … See more Also called knit lines, these defects mark where two flows of molten resin came together as they moved through the mold geometry. This … See more WebApr 14, 2024 · Common injection molding defects of PP 1. Lack of injection. Fault analysis and troubleshooting methods: (1) Improper control of process conditions. Should be adjusted appropriately. (2) Injection capacity of injection molding machine is less than weight of plastic part. It should be replaced with a larger size injection molding machine. how big is hinkley point c site
Plastic Injection Molding Defects series-Flow Marks or Flow Lines
WebApr 10, 2024 · Unreasonable hot runner size. Solution. Improve injection speed and melt flow. Improve the exhaust system of the mold. Increase the mold wall thickness and switch to a grade where the melt flows easily. … WebJan 24, 2024 · Switch to a hot runner or reduce the size of the main channel. 2. Sink Marks. This type of injection plastic defect occurs as small depressions or recesses. These features occur on flat and consistent … WebAvoid Drag in Molded Parts. Sufficient draft is an important part of any mold design, and quick-turn tooling is no exception. Vertical walls, meaning those part surfaces parallel to the direction of mold operation, should have a … how big is hitachi