Key Rubber Parts Defects You Need To Know

Have you ever wondered about the most common rubber parts defects and how these could impact your projects? There are numerous different rubber parts defects, and these often arise during the molding process. Being aware of these defects can potentially be hugely helpful in your own manufacturing goals, too.

What is the Rubber Molding Process?

Before we begin looking at some of the main rubber molding defects and remedies, it’s worthwhile to consider how the rubber molding process works.

There are three main rubber molding processes: injection molding, transfer molding, and compression molding. Each of these works in a slightly different way, which can influence their final properties (and the defects they experience). However, compression molding processes are often among the simplest and most effective, which is why many professional rubber molding brands – such as our own – focus on these methods to provide top-rated products.

Common Rubber Parts Defects

In any of the aforementioned rubber molding processes, defects can arise in the final product. This can make your rubber parts more difficult to work with or, in some cases, make them entirely unusable.

Some of the most common rubber parts defects you might experience include the following points.


In some scenarios, rubber parts can shrink after they have been removed from the mold. This may be because the mold cavity itself is too small for the final size of the part; as a result, it’s possible for the product to either shrink after being removed or otherwise be an unsuitable size.


In many scenarios, warping can occur when the rubber part doesn’t cool as intended, resulting from improper molding conditions. Warpage may mean that the final part is , and this will usually make most parts defective.

Brittle Materials

If you notice that your rubber parts seem to be brittle after the molding process, this could potentially increase the risk of further defects arising down the line too. Brittle rubber parts are incredibly likely to crack, and in some cases, they could break completely – certainly not living up to the elasticity expectations of typical rubber parts.

Excess Material

rubber parts defects Excess Rubber
rubber parts defects Excess Rubber

In some cases, weaknesses in the molds can cause excess material and shape deformities in your rubber parts. Though this can often be fixed simply by trimming off the excess, it’s nevertheless a frustrating scenario to find yourself in, especially if this seems to continue happening.


In some cases, if the materials used during the rubber molding process are not completely pure, contaminants could be used in the rubber part’s production. Contaminants can be a significant issue, in many cases, since they may compromise the strength of your rubber parts overall. In line with this, partnering with a professional team that uses suitable quality control and contaminant prevention strategies is integral.

rubber defects Contaminants
rubber defects Contaminants

Under certain circumstances, contamination may not be a major problem – for example, this could cause slight discoloration of the final rubber part. However, contaminants could severely hinder the part’s suitability in many cases, especially if found in significant quantities in the final product.


In a handful of cases, porosity can become a notable issue with your rubber parts. Porous rubber parts will allow water to pass through in significant quantities or just a little. Nevertheless, this can represent a significant issue, especially if the rubber part is being used to seal a system where water could cause problems overall.

Underfilled Molds

rubber defects NonFills
rubber defects NonFills

Underfilled molds are one of the most common causes of rubber parts defects that you should be aware of. When a mold is underfilled, key parts may be missed – for example, an important part of a design. This can make a significant difference when it comes to your ability to use the tool, as it may be unfunctional.

How to Resolve Rubber Parts Defects

If you have experienced rubber parts defects with your own manufacturing lines, there are several possible options you could consider to resolve them. Keeping these potential issues in mind can be a simple way to ensure that your rubber parts are manufactured successfully. And, when looking for a rubber parts manufacturer to help, be sure to check that these are always carefully scrutinized as part of the quality control process for your chosen brand.

Ensure Proper Filling of Molds

One of the most important things to do when it comes to rubber parts defects is to ensure proper filling of molds. In many cases, improperly filled molds are a major cause of issues when it comes to your rubber parts, so increasing the shot size or taking greater care in terms of the filling process can help with filling the molds fully.

Increase System Pressure

Shrinkage can be a major problem, but this is often easy to resolve by increasing the pressure in the cavity. However, if you attempt to increase the system pressure, ensure that doing so will not compromise the system’s safety.

Increase Cycle Time

If you don’t keep a long enough cycle time, you might find that your rubber parts end up warping. In line with this, increasing the cycle time may prove helpful if you have been having difficulties with warpage or shrinkage.

Use Large Molds

If you have been having difficulties with your rubber parts shrinking to a too-small size, using a large mold can often offer a simple solution to overcome this challenge. The mold cavity should always allow suitable room for any shrinkage that may occur; a professional brand should be able to account for this when calculating the mold size and capacity.

Change Temperatures

Having the wrong temperature in your rubber molding system can play a significant role in influencing the final characteristics of the material. If you have noticed that your rubber tools are brittle, this may be due to lower mold temperatures; alternatively, if you’ve noticed a warpage in the material, you may need to increase the temperature somewhat.

Contact a Professional Team for Further Manufacturing Support

Of course, if you repeatedly experience rubber parts defects, it may be worth looking for a different supplier instead. Professional rubber parts manufacturers, such as our experts here at Jiangzhi Rubber and Plastic, should be able to help you find the ideal solutions for your struggles.

Remember: many of the most common rubber parts defects can be resolved simply by using effective manufacturing strategies! Fortunately, our experts integrate the best possible manufacturing processes at every stage, ensuring you get amazing results for your rubber parts every time.

Final Thoughts

Being aware of the most common rubber molding defects and remedies is crucial if you have been looking for new ways to streamline your business’s operations. Indeed, rubber parts defects can be a massive pain in many cases – but this shouldn’t have to hold you back from achieving your goals.

As such, we have outlined some of the most important features of rubber molding defects today to help inform your decision. Hopefully, this will allow you to integrate common remedies to overcome such defects; after all, you’d be amazed at how simple some of the most common rubber defects can be!

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