Overmoulding for Strain Relief

Strain Relief

A strain relief is a standard feature in cables for relieving the stress and tensions between the rigid connector or device and the flexible cable. The point at which a cable exits a connector body or other component can be a critical failure point because of repeated flexing therefore a well-designed strain relief is vital for the mechanical and electrical integrity, optimum lifespan and general performance of all types of cables.

Strain relief sometimes comes in the form of an off-the-shelf part that is slipped onto the cable before the connector is terminated. After termination the strain relief is screwed into place, capturing part of the connector and covering the joint.  But often when these components are assembled, they do not offer the required degree of IP protection.

By far the most superior strain relief in most applications, is a custom designed, overmoulded strain relief which will offer superior flex life, a far greater degree of moisture and dust protection and enhanced tensile strength because of the bonding achieved during the overmoulding process. Overmoulding the contact and wire termination area can improve the pull-force performance, typically by a factor of two to three times.

An overmoulded strain relief can take on any form with as much built in flexibility as required.  It provides the opportunity to have customised logos and part numbers embedded into the structure.  It can be designed solid and smooth or segmented with a textured finish.  The choice will usually depend on the application and intended environment of the finished product. A solid strain relief is easier to clean which can be an important consideration for applications such as medical.  If the material, size and geometry are the same, a segmented strain relief typically offers greater flexibility than a solid strain relief, but with the trade-off of being more difficult to clean.

It is generally accepted therefore that an overmoulded strain relief offers superior performance on several levels. Strain relief of course is just part of the story.  Overmoulding offers moisture protection, vibration proofing, backfilling, high voltage insulation, improved aesthetics and added value to your product.

As the leading specialists in over moulding applications, here at Overmould we deploy Henkel’s excellent range of Technomelt low pressure moulding products that meet UL94 V-0 requirements.

We offer design, engineering, prototypes, turnkey manufacturing, Mould Tooling and training and have clients in every major industrial sector, providing diverse solutions to a range of problems and overmoulded assemblies to a wide range of innovative applications.

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