What is Heat Shrinking in Cable Assemblies?

Heat shrink tubing can be an incredible value-added component to a cable assembly with increased strength, durability, and resiliency in one, easy package. However, there is obviously a cost involved with any additional parts being incorporated into a custom cable assembly. So, how do you best use heat shrinking in your cable assemblies to be both cost-effective and return value? 

To answer that very question, we’ll deep dive into the wide world of heat shrinking to show you just how useful this process can be. Bonus alert, we’ve also included a video showing wires being soldered to a DB15 connector and the solder joint covered by heat shrink tubing to give you an insider’s look into the process.  

First Off, What is Heat Shrink?

Heat shrinking, heat shrink, heat shrink tubing—these are all referring to the same process we use in custom cable assemblies every day. This process utilizes a tube that can shrink in a radial pattern around a given component when a heat source is applied. There are different processes used to produce different results within heat shrinking but in general, a one-two punch is useful for the widest varieties of applications (think acting as an insulative material, beefing up connections and terminations, or even as wire management for unbundled wires).

Step One for Heat Shrinking

With many of the heat shrinking applications we employ here at Meridian, step number one is going to be extrusion. With advanced machinery and technology, our gifted cable engineers are able to extrude conductors as small as 34 gauge or as large as 12 gauge—a really useful capability for producing high-quality cable assemblies. However, with heat shrinking, we’re actually extruding the material being used for the tubing itself. As with all of the different materials that make up a given cable assembly, tubing material can vary dramatically based on whatever application our client needs. 

Heat Shrink Tubing Step Two

Next up, our team is going to use a very detailed process with different amounts of gradual heat and variable force to produce the exact diameter of heat shrink tubing required for the project. This step requires some truly advanced computations which our cable engineers work through with the help of high-tech computer-aided design and simulation software. 

Once the specs are set, we’ll utilize advanced machinery to produce the heat shrinking effect. After heating and expanding, the heat shrink tubing can cool down but remains in the expanded state. This allows for an easy application to whatever component requires this stout level of defense. When heat is applied yet again, the heat shrinking will live up to its name and diminish in size to encapsulate the part of the assembly being worked on.

How to Use Heat Shrink Tubing Effectively

Heat shrink tubing is most effectively used as a protection mechanism that completely envelops whatever is beneath it. The cables, wires, connections, terminations, and more than comprise a custom cable assembly can be subjected to all manner of external forces that might degrade the assembly. 

When used with any one of the many applications cable assemblies find themselves in, there can be a variety of external forces hammering the assembly including:

  • Vibrations and abrasions
  • Cable strains
  • Moisture
  • Dust
  • Chemicals
  • Cuts
  • Even impacts 

At Meridian, we produce cutting-edge cable assemblies for the military, hospitals, automotive OEMs, advanced telecommunications, and so much more. Within these applications, heat shrinking can be an incredibly powerful, yet overall simplistic, way of protecting the transmission of an unfettered stream of data, power, and/or signal through the system.

But even beyond the stout level of protection that heat shrink tubing provides, another very necessary, but not all that glamorous, benefit can be found. Cable wire management is so crucial for both integration and maintenance once a cable assembly is employed in its final destination. Heat shrinking allows for a color code to be developed and used in quick identification of the myriad components by using different colored tubing. Even aesthetics can benefit from the sleek and clean look of a heat shrink tubing for a final product presentation that’s pleasing to the user’s eye. 

Bottom line, using heat shrinking within a cable assembly produces a world of benefits that can dramatically improve many different categories of the overall assembly. 

Applications For Large Heat Shrink Tubing

One of the most common applications for large heat shrink tubing projects is using polyolefin tubing because of the high temperatures this material can withstand and still hold its protective qualities. Polyolefin is a great protector but it also is more expensive than more common tubing materials like polyvinyl chloride (PVC). For its low price point and ease of application, PVC tubing is one of the most common materials used in large-scale volume manufacturing. 

PVC heat shrink tubing has its own pros and cons, as does any material, which can help our cable engineers know when its use is going to provide the most bang for the buck. It is a lot cheaper than a material like a polyolefin and it’s also able to use more vivid coloring or even be made to be clear. Both of these can help with aesthetics and sound cable management principles. PVC will also provide a degree of flame resistance when that’s engineered in, as well as a few grades higher on strength and ability to resist abrasions. 

Using Heat Shrink Tubing in Your Custom Cable Assembly

Now, while PVC is great for large heat shrink tubing applications, there are so many other materials out there to choose from that each offer up their own blend of unique qualities. After decades as leaders in employing processes like heat shrinking in our cable assemblies, our team has an intimate knowledge of how, when, and where a material can be best employed depending on the needs of the project. 

There are heat shrinking out there that also have adhesives added to the lining that’s referred to in the industry as dual-wall tubing. The inner wall will actually conform around whatever is beneath it when heat is applied which can fill any voids within the system. Once hard, this produces a rock-solid defense against environmental variables. 

Other materials out there that are great for specific applications include:

  • Polytetrafluoroethylene (Teflon)
  • Silicone
  • Fluorinated ethylene propylene (FPE)
  • And other advanced materials

The main advantage to working with an established cable assembly manufacturer is going to be the knowledge and experience to know when is best to use a specific material in the assembly. Our team has seen so many different applications over the years and have kept up with the ever-increasing complexity of technology in order to produce cable assemblies that fit perfectly within their intended environments. 

Choosing When to Use Heat Shrink Tubing

Choosing the best applications is both data and intuition driven. Our team knows the materials we have at hand and the tools at our disposal to produce the perfect component for a given cable assembly or wire harness design. Remember that heat shrink tubing is produced when heat is applied to the tubing material. There are two general ways to go about the application of heat that can produce different results for the final product. Heat shrinking the material in the oven or using a hot gun are two of the most common methods we’ll employ but there are others out there for very specific applications. 

In general, the heat shrink tubing can be decided upon given the original specifications set forth by the client. Our cable engineers take these specifications as the parameters they have to work with and utilize a tool crib of well over 5,000 existing tools for connectors, junctions, overmolds and housings for cable assemblies. Knowing the specs, our team will produce tubing that can be classified into different shrink ratios. 

If you are doing research on heat shrinking ratios, you will probably see three of the most prevalent being two-to-one, three-to-one, or four-to-one ratios. This means that the original material will be two, three, or four times as large as the heat shrink tubing turns into. Precise measurements are absolutely critical in custom cable assemblies and all the more so with heat shrink tubing. Our team looks at the size of the components to computate the precise size of shrink ratio needed to produce a cost-effective solution. 

Start Your Cable Design with Heat Shrink

From a quick solution for cable jacketing, to a powerful seal against external factors that can degrade a cable assembly, heat shrinking is an incredibly useful process to have in our tool kit. When our clients need heat shrinking in a cable assembly, we’ll help examine all of the specifications and look at the application to recommend the perfect blend of materials and processes that will provide a cable assembly that can be counted on. 

Our team is also pretty finatical about quality assurance which is why each and every product we make is 100% tested for continuity, integrity, polarity and functionality before ever shipping on to the client. Contact our team today to get started.