How to Avoid the 5 Common Injection Molding Design Mistakes?

Injection molding is one of the most popular manufacturing techniques in use today. This method is preferred due to various benefits it offers. The process of injection molding is best suited when large quantities of highly repeatable parts are desired at a fairly low per-piece cost. This post will discuss some of the common mistakes that occur during injection molding, and how to avoid them.

What are the Common Injection Molding Mistakes and How to Avoid Them?

Be sure to avoid the following mistakes when designing for injection molding, and enable yourself to take full advantage of the benefits that the process offers.

  1. Flow Lines: The flow lines are also caused when the plastic flows through sections having variable wall thicknesses, or when the speed of injection is too low.

    How to Avoid?

    To avoid the above mentioned defect, the injection speed and pressure should be increased to the optimal level. This will ensure that the cavities are filled evenly.

  2. Molding Defects: During the molding process, a flash can appear on your product. This is usually the result of poorly built or inaccurately cut molds. A flash can also occur as a result of excess pressure during the injection phase.

    How to Avoid?

    You can avoid this by reducing injection pressure. However, too little pressure may result in an unfinished part. Thus, you should be certain to have suitable clamp pressure so it is tight at the parting line.

  3. Sink Marks: The sink marks are caused when the plastic is not cooled and cured properly. These marks are also a result of excessive temperature at the gate, or inadequate pressure in the cavity.

    How to Avoid?

    To avoid this mistake, holding pressure should be increased, mold temperatures should be lowered, while the holding time should be prolonged to allow adequate cooling and curing of plastic.

  4. Contamination: Over the time, the injection molds get contaminated with carbon, oil, material gassing, rust, and grease. The contaminated molds start producing inferior products.

    How to Avoid?

    You should clean injection molds regularly. This practice will help reduce costs in a long run.

  5. Burn Marks: These marks are either caused by fast injection speeds or due to degradation of the plastic material caused by overheating. The burn marks are also caused due to excessive heating of trapped air, which scores the surface of the molded part.

    How to Avoid?

    You can avoid this by either reducing injection speeds, or by reducing mold and melt temperatures, or by optimizing gas venting and degassing.

All of the aforementioned mistakes and defects can be avoided in the design process by using appropriate tooling design. With the help of this, you will be able to design solutions to these problems. Thus, you do not have to worry about the defects when it comes to production.Also know more about tips to make injection molding processes beneficial and productive.