gas assisted injection mold in China

How to make gas assisted injection mold?

The gas-assisted injection molding is a process that involves the traditional, low-pressure process of injection molding. This process uses pressurized nitrogen gas to force material into a mold. Let’s find out more about gas-assisted injection molding.

gas assisted injection mold in China
gas assisted injection mold in China

Basically, this process is used to produce big parts of plastic using complex designs and beautiful surface finishes. Normally, this process is a great choice for making skins, cabinets, bezels, doors, equipment covers, and handles.

Internal Injection Molding

As said earlier, this process injects pressurized nitrogen gas into a mold. Actually the nitrogen gas is passed through the gas channels for displacing the material through the creation of hollow sections.

The molten resin is pushed against the wall of the cavity until the solidification of the path. The constant pressure of the gas prevents the shrinkage of the part. In addition, it reduces internal factors, sink marks, and surface blemishes. So, this process can work well to hold curvatures and tight dimensions.

External Injection Molding

In this type of injection molding, the material is pushed into the mold. However, the gas is pushed in a very thin layer between the mold core and the back surface of the component. So the front surface of the component is forced against the other side of the cavity of the mold. as the gas cools down, different sides of the component replicate the mold surface.

Basically, this process is suitable for plastic parts that feature large surface areas, especially those parts that require beautiful surface and detailed textures. In this process, the sink and warp marks are removed because in nitrogen gas maintains the material condition.

Just like internal gas assist, the bosses and support ribs are molded into the component and produce the same level of tolerance and dimensional stability. In the same way, molding pressure produces less stress wear and tear.

Cost Considerations

This process also helps save a lot of money. Typically, these processes require a lot less force than traditional injection molding. Therefor it helps reduce the component chords costs and produces less stress as well.

Actually, the mold pressure results in reduced wear and tear. Therefore, there would be less demand for pricey aluminum tooling. Moreover, the parts made are lightweight which will help reduce the freight expenses and boost material handling.

Design Benefits

Moreover, this technology results in a lot of performance and design benefits. For example, multiple parts with different thickness off walls can be molded.

Converting different components to Gas Assist

This type of injection molding is a better alternative to the large metal parts. Therefore, it is possible to eliminate expensive, heavyweight, corrosive components like panels, access doors, enclosures hand covers.

In short, this was a brief introduction to gas-assisted injection molding. Hopefully, this article will help you understand the concept much better.

Resource box: This article is originally posted in https://www.injectionmouldchina.com.

injection molding defects

How to eliminate injection molding defects?

Injection molding is an art, which involves science as well. Actually, injection molding requires great attention to detail as minor mistakes can cause a lot of financial loss to a company. In this article, we are going to discuss how you can eliminate common injection molding defects.

injection molding defects
injection molding defects

Flow Lines

Flow lines may include lines, patterns, and streaks that appear on the prototype part because of the cooling profile or physical path of the molten plastic while it moves into the cavity.

Fix:

  • One way to fix the issue is to increase the pressure and injection speed, which will make sure that the mold will fill the cavities.
  • Another way is to round the locations and corners where the thickness of the wall changes.

Sink Marks

These are minor depressions or craters that form in the thicker areas when shrinkage happens in the internal areas of the end product.

Fix:

  • Reduce the mold temperature, increase the holding pressure and time for better curing and cooling.
  • Reduce the thickness of the wall sections that are the thickest. This will allow faster cooling and prevent the sink marks.

Vacuum Voids

Vacuum voids refer to the air pockets inside or near the prototype surface. They occur because of the uneven solidification amidst the inner sections and the surface.

Fix:

  • Find the gate at the mold’s thickest part
  • Opt for the plastic that is less viscous, which will reduce the amount of gas trapped.
  • Increase the holding time and pressure
  • Try to keep the mold parts aligned

Surface Delamination

Surface delamination happens when thin layers of the surface show up on the part because of a contaminant. Actually, these layers look like coats that can be peeled off.

Fix:

  • Before molding, make sure you dry the plastic properly
  • Raise the degree of mold temperature
  • There should no sharp turns and corners in the mold design

Weld Lines

Weld lines show up on an area where the liquid plastics mixes while they flow from different injection mold parts.

Fix

  • Increase the temperature of molten plastic or mold
  • Raise the injection speed
  • Make adjustments to the design to ensure that the flow pattern is only one source flow

Short Shot

Short shot refers to a situation that happens when a molding shot tends to fall short. In other words, the molten plastic won’t fill the cavity of the mold for some reason. As a result, it leaves a portion where you can see plastic.

Fix

  • Opt for a plastic that features higher flow and less viscosity
  • Raise the mold temperature for better flow
  • Get a machine that features more material feed

To cut a long story short, you may have to face a lot of defects during the process of injection molding in China. What you need to do is follow the tips given in this article to fix or eliminate these issues to make the process error free. Hopefully, you will find these tips helpful.

Resource box: This article is originally posted in https://www.injectionmouldchina.com.