Welcome back to our multi-part series on overmold materials for custom medical cables! Last time, we looked closely at Thermoplastic Polyurethane (TPU), a material prized for its toughness and flexibility. You’ll want to check out this one if you’re working on next-gen medical devices—perhaps something like advanced oncology tools where precision and durability are non-negotiable. Today, we’re shifting gears to explore Thermoplastic Elastomers/Rubbers (TPE/TPR), a versatile option for making high-performance cable assemblies.

Why TPE/TPR Matters for Your Next Project

TPE/TPR—often recognized by the trade name Santoprene®—brings a unique blend of rubber-like elasticity and thermoplastic processability. This material offers a compelling solution for engineers designing cables that need to endure harsh environments (think frequent chemical wipe-downs or flexing in tight spaces). It’s not just about surviving the day-to-day grind; TPE/TPR can elevate your design by balancing performance, manufacturability, and even aesthetics—all critical when your device is part of a life-saving system.
What sets TPE/TPR apart? Its excellent chemical resistance is a standout feature. Unlike some materials that buckle under common disinfectants, TPE/TPR holds its own, making it a go-to for cables that must stay reliable through rigorous cleaning protocols. Plus, with the right design tweaks, it can handle up to 50 steam autoclave cycles—a game-changer for reusable devices where sterilization is necessary.

The Engineering Edge: Shrinkage and Design Considerations

Now, let’s get to the nitty-gritty that keeps engineers up at night: shrinkage. When TPE cools from its molten state, the molecules align and contract, typically in the thousandths-of-an-inch range per inch. It might sound minor, but this can make or break your tolerances for precision applications. Uneven shrinkage could warp a strain relief or throw off a yoke’s fit, especially in assemblies where cables connect to intricate components like sensors or probes.
Here’s the workaround: clever tooling design. At ClearPath Medical, we cut insert mold tooling slightly larger than the final part size to account for this shrinkage. It’s small and weak with big payoffs, ensuring your overmolded parts pop out of the mold with the exact shape and functionality you intended. For engineers, this means fewer headaches during production and a smoother path to validation.

Flexibility Meets Functionality

TPE/TPR isn’t just surviving the mold—it’s about living in the field. You’ve got options with a Shore A hardness typically ranging from soft and pliable (around 80 or less) to slightly more rigid (90 and up). Need a cable with bend relief that flexes effortlessly in a handheld device? Go softer. Designing a segmented strain relief that needs some stiffness to protect delicate wiring? Dial up the durometer. This tunability lets you tailor the material to your application’s demands, whether navigating tight bends or standing up to repeated use.
Let’s not overlook the exterior cable jacket. TPE/TPR isn’t limited to overmolding—it’s also a popular choice for cable jacketing. Why? It’s tough, semiconductive, and can take a beating without compromising the conductors inside. For devices that might see everything from alcohol swabs to accidental drops, that’s a win. 
Real-World Impact for Next-Gen Devices
Picture this: a cable assembly for a cutting-edge diagnostic tool, maybe one used in oncology treatments. It’s got flex without failing, resists harsh disinfectants, and looks good—all while keeping costs in check. TPE/TPR checks those boxes. Its processability in vertical clamping injection molding machines means we can precisely churn out complex, multi-lead configurations, even for low-to-mid volume runs. Pair that with interchangeable mold tooling, and you have a solution that adapts as your product line evolves.

Got a tricky design challenge on your hands?

We’re here to help brainstorm solutions that push the boundaries of what’s possible in medical cable assemblies. Contact us at ClearPath Medical to keep the conversation going—your next breakthrough might just start with the right material.

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Autoclave sterilization Cable assemblies Cable jacketing Chemical resistance Flexible cables Medical Cables Medical device design Medical engineering overmolding Precision manufacturing Santoprene Shrinkage in molding strain relief Thermoplastic elastomers TPE/TPR