Overmolded Cable Assembly Guide: What It Is and Why You Need It

molded cable assembly

Overmolded cable assemblies are icons for the strength and resiliency they add to a cable assembly. Cable overmolding is used to protect the assembly to endure some of the toughest conditions Planet Earth (and beyond) has to offer. 

As leaders in the design and manufacture of the modern overmolded cable assembly, Meridian helps our clients know when’s the best time to employ cable overmolding within their custom cable assembly design project to get the maximum benefit. 

What is cable overmolding?

Cable overmolding is a process where either insert molding or injection molding is used to combine wires and connectors into a unified piece. The cable overmolding design process involves placing the cable assembly components within a mold, then covering with a hot liquid plastic material by means of injection. Once it has a chance to cool, the final product will match whatever mold was used and if done correctly will protect the connection of the underlying wires and connectors. 

Overmolding is an ideal solution for providing a seal for cable assemblies and their connectors. This is especially useful in situations where the assemblies will face rugged or extreme conditions. As well, overmolded connectors offer medical practitioners with an assembly that can withstand sterilization procedures and also comes with built-in strain relief. 

Other considerations for multiple applications include incorporation of Electromagnetic Interference (EMI) and Radio Frequency Interference (RFI) shielding. From industrial control systems to telecommunications, the overmolding process helps to create one-of-a-kind cable assemblies built to withstand tough environments. This is achieved because of advanced mechanical strength and flexibility in design. Aesthetics also play a major role, aiding both in a good look and feel, as well as helping incorporate the assembly into an existing system.

What are the benefits of using overmolded cable assemblies?

Beefing up the construction around a cable assembly’s connection point provides several key benefits. Simply put, the benefit of using a cable overmolding means the cable assembly should last longer and perform better than it would without the added protection. 

An overmolded cable assembly provides a host of other benefits including:

  • Increasing the flexural strength, especially where the cable exits. This area is going to bear the brunt of movement in most situations so additional strength is required to make sure the connection remains reliable.
  • Increasing the level of protection overall against outside forces like temperature swings, moisture, rubbing, impacting, and shocking.
  • Enhancing the physical security for the cable assembly.
  • Increasing the strain relief provided, as well as the pull strength.
  • Creating a seal for the cable assembly connection that can be completely water-tight, resist moisture, resist oil, and provide some other resistance based on the needs of the application.
  • Helping to improve the aesthetics of the assembly and making visual cues that aid with installation of the assembly into its intended system.

The benefits of overmolded cable assemblies are many but there is an increased cost associated with adding these extra layers of protection. Careful considerations like these are best made with the help of an experienced custom cable assembly manufacturer. At Meridian, we specialize in custom solutions and can develop the perfect solution to meet budgetary and time constraints. 

Customization Options for Overmolded Cable Assemblies

One of the top benefits of using a custom cable manufacturer lies in the fact that you can tweak each element in the design process in order to produce the most efficient version of a product. Our design engineers can customize a variety of the aspects for an overmolded connectors and cable assemblies including:

  • Changing up colors to meet the client needs, make it easier to install, more aesthetically-pleasing, etc.
  • Incorporating corporate logos or names.
  • Including attachment hardware like flanges.
  • Changing the angle of the exit point whether that’s straight, at a right angle, or just about any other customization required.
  • Using any one of a number of different materials like PVC and TPU (more on these later).
  • Utilizing different processes like low pressure and injection molding.

Customization options abound when working with a custom cable assembly manufacturer like Meridian. In fact, we design over 70% of the products we manufacture. With an incredible tool crib of more than 5,000 existing tools, connectors, and other components, we can provide the perfect amalgamation of cable and wire for your assembly.

How it’s Made: Overmolded Cable Assembly Edition

In order to produce an overmolded cable assembly, you need a sophisticated piece of machinery known as an injection molding machine. The machine is able to push the overlay material into a mold at a high degree of pressure. Usually a thermoplastic polyurethane (TPU) or thermoset plastic is used to be injected into the mold. 

Injection Molding Machines

Knowing the right tools for the job is crucial in any design process. When it comes to injection molding machines, the engineers have to use a machine with the desired tonnage for the project. The tonnage is how much force the machine has to exert to keep the molten resin within the mold. The bigger the mold, the more force is required to produce a viable final product.


Our engineers determine the most effective materials to be used in the overmolded cable assembly. Different materials have different benefits like increasing how rigid the assembly is, or conversely, how flexible it can be. 

Common overmold materials used in cable overmolding include:

  • Polyvinyl chloride (PVC) is a very common material because it has excellent durability and the ability to resist moisture. It also is able to withstand a good degree of tension and is versatile. 
  • Thermoplastic Polyurethane (TPU) is great because it resists fraying and has a high degree of elasticity. TPU is particularly suited for cold regions.


During the injectable molding process, the mold resin goes from the hopper and into the molding machine. Here, it can be mixed with different additives and then an injection screw pumps it into the mold cavity. The mold itself can be customized with things like logos or part numbers. As the material is heated in the barrel of the screw, it will begin transgressing down into the tooling for the mold. 

The liquified and molten resin starts to collect towards the end of the barrel, ready to be shot into the mold’s cavities. There is almost always extra allowance for the shot amount since some of the resin will more than likely shrink. Within just a few seconds, the mold’s cavities are filled with the molten resin. The screw is designed to continue applying pressure to allow for the resin go start to cool and begin solidifying. 


Sometimes our engineers need to add in a circulating water or oil to help with cooling and cut down production time. Once cooled, the molded component can be removed from the mold and will bear whatever design the mold incorporates. 

What’s in a Mold?

A mold is the actual tool that is used to create the overmolded cable assembly. As a custom cable assembly manufacturer builds up their experience, they begin to amass many different tools as a project is just as likely to require the fabrication of a whole new tool to complete the job. How long a mold is used as a tool is dependent on its purpose and what it’s made out of. 

As with everything in life, the larger and more complicated the mold is, the more expensive it will be. Molds can be made with different metals or can require detail work that causes the price to fluctuate. When molds are needed to produce again and again in a volume manufacturing setting, it’s generally best to use a metal like a hardened steel. This can be more costly initially but the hardened steel molds are made to last a really long time and will produce a lot of overmolded cable assemblies during its useful life.

Molds are also commonly made out of aluminum when they are being employed during the prototype process. Prototyping provides our engineers with a chance to see how different components will all come together before moving into larger scale production. By prototyping, we’re able to spot potential issues and put safeguards in place, before project variables might otherwise hinder production. This level of commitment is what’s helped us produce the high-quality overmolded cable assemblies used in everything from military communications gear to cutting-edge hospital equipment.

Start Your Overmolded Cable Assembly Project 

As professionals in the field of custom cable manufacturing, we take great pride in the integrity of our design and products. Each and every product we produce is tested and retested before it’s ever shipped so that our clients know they can depend on the cable assembly to perform perfectly within it’s destined environment.

Overmolded cable assemblies can be the perfect addition to your custom design project to really increase the level of protection of the assembly. Providing the necessary level of protection against environmental factors helps cable assemblies last longer in the toughest environments imaginable. Contact our team now to go over your project’s unique specifications and to start the design process.