Table of Contents
What are the defects of injection molding?
Top-10 Injection Molding Defects And How To Fix Them
- Flow Lines.
- Sink Marks.
- Vacuum Voids.
- Surface Delamination.
- Weld Lines.
- Short Shots.
- Warping.
- Burn Marks.
What is Burr injection molding?
Flash. Flash, also called “spew” or “burrs”, is an excess of molding material that appears as a thin lip or protrusion at the edge of a component. Flash appears because material has flowed outside of the intended flow channels and into the space between the tooling plates or at the injector pin.
What are the defects in plastics?
Common Defects
- Blister. A blister is a raised area on the plastic surface, very similar to the medical condition of the same name.
- Burn Marks. Burn marks are generally caused by problems similar to blistering.
- Burrs.
- Embedded contaminates.
- Flow marks.
- Lamination.
- Sink marks.
- Short mold.
What causes high gates in injection molding?
Injection fill speed is too high. The speed at which resin enters the mold has a big impact on finished parts. If the mold is filled too quickly, the molten plastic will react to the flow restriction at the gate.
How can we prevent defect injection?
Solutions
- Increase the injection pressure, speed, and material temperature.
- Add some more distance between the mold gates and the mold coolants.
- Increase nozzle diameter.
- Switch to a hot runner or reduce the size of the main channel.
How do you remove burrs from plastic?
CO2 blasting can be used to deburr and deflash various plastic parts, such as PEEK, nylon, ABS and other thermoplastics. Burr removal using CO2 blasting compliments in-process or post-process deburring of plastic components, eliminating burr formation and reducing the size and volume of burrs.
What is the difference between burr and flash?
Burrs are residual flakes or chips of material that remain once a part has been machined. One thing to keep in mind is that burrs occur on machined parts, not molded parts. Flash on the other hand, occurs on molded parts, whether compression molded, transfer molded or injection molded.
What causes flow lines in injection molding?
What Causes Flow Lines? Flow lines are often the result of variations in the cooling speed of the plastic as it flows in different directions through the mold. They also can occur when you’re creating pieces of differing thicknesses, as the thinner areas cool before thicker areas are fully filled, causing flow lines.
What causes splay in injection molding?
Splay is caused by tiny gas bubbles that are dragged across the surface of the part when the mold cavity is filled. Splay is usually caused by water that is absorbed within the plastic granules. As the mold fills, the steam migrates to the surface of molded part. It is these steam bubbles that you see as Splay.
What is EDGE gate?
Edge gates are the most basic type of gate. They are normally rectangular and attach to the part along its perimeter at the parting line of the mold. They are used when automatic degating is impractical.