Formable Probe Cable for Borescope and Inspection Leads

What a formable probe cable is asked to do

A formable probe cable has one job that ordinary cable does not: it has to stay where the operator puts it. Set the head at an angle, let go, and it holds while the image is read or the measurement is taken, then it gets re-bent for the next view, hundreds of times a shift. At the same time it is still a signal cable, and on a video or ultrasonic head it is carrying the one signal that cannot be noisy.

The construction we build most often is enameled copper wound around a stainless shaping core, then shielded and jacketed. The copper carries the signal, the steel core holds the shape. Winding rather than laying the two side by side keeps the neck round, keeps the shield geometry stable as it flexes, and gives one cable instead of two that would have to be taped together.

One word on this page matters more than the rest of it: formable.

Formable is not shape memory, and the difference decides your design

Inspection necks are where the word memory wire causes the most trouble, because two unrelated materials share the name.

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Our work is the left column. A neck that must hold the angle you set is a formable job, and we run those every week. A part that is meant to move itself once heated belongs to the shape memory world, comes from other suppliers, and is outside what we do. Tell us which one the drawing means.

How stiff should the neck be?

Stiffness is a trade between holding a heavy head steady and being pleasant to re-aim. A soft neck under a heavy head droops; a stiff one fights the operator and loads the bend harder. Tell us the head weight and how far it hangs off the end of the neck and we can size the core from that.

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Why the neck wears through where it bends

This is the failure mode specific to the construction, and an inspection neck sees it faster than almost any other product because it is re-bent constantly rather than set once. The enameled conductor lies against the steel, so each re-aim rubs the coating against harder metal. When it goes through, the copper meets the core and you get an intermittent fault that appears at one neck angle and disappears at another, which is the worst kind of fault to chase in the field.

Three things control how long the neck lasts: the bend radius it is asked to take, whether there is a serving layer or separator between copper and steel, and the enamel grade. The first two you settle with the core choice; the third carries a trade-off, covered next.

Shielding and signal integrity in a bending neck

Putting a signal cable around a steel core raises two questions that a normal cable does not have. The first is what the core is tied to electrically. Left floating, a metal core running the length of the neck can pick up and re-radiate noise. Bonded at one end, it acts as an extension of the shield. Bonded at both ends, it can carry ground-loop current. Tell us what you want it tied to and we build it that way.

The second is how the shield survives repeated flexing. Braid holds coverage well but adds stiffness and diameter. Spiral shield is more flexible and less robust over many cycles. Foil is light and does not like repeated bending. Which one is right depends on what the head outputs, so we ask before we quote rather than choose for you. If the neck carries a vision signal on a fixed mount, our USB3 Vision camera cable is the closer starting point.

We do not publish attenuation or impedance figures for a formable neck. Those come from your construction, your length and your head, and they are measured on the finished assembly against your specification.

Solderable or scrape-resistant enamel: pick one

The coating has to survive rubbing against the core and still come off cleanly at the ends. Those two requirements pull in opposite directions.

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Solderable families we open with a timed immersion. Anything tougher needs its own process, and in a slim neck holding many conductors the stripping method sets both yield and piece price, so we want the grade confirmed before we quote.

For background on the equipment these necks serve, see the general reference on borescopes.

Through the strain relief, the overmold and the wall

The neck is stiff and the cable behind it is not, so the transition is where these assemblies break. We mold a strain relief long enough to spread the bend over a usable length, and we capture the steel core inside it so the core cannot walk. Stainless will not take solder with standard flux, so the core is crimped, spot welded, or trapped in the molding. If your design needs the core bonded or grounded, say so on the drawing, because it changes the tooling. It is also worth remembering that stainless has roughly forty times the resistivity of copper, so the core is never a substitute for a conductor.

Where the neck has to pass through a panel or an enclosure wall, the seal is a separate decision from the cable: our medical panel feedthrough set is built for exactly that. For imaging heads that combine a neck with many coax elements, start from the ultrasound probe cable assembly.

What we need from you to quote

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How we build and inspect them

Everything is assembled at our Shenzhen plant: four production lines, about forty assembly operators, and molds cut in house, which is why a custom overmold does not add weeks to the schedule. Minimum order quantity is typically 500 pieces, samples leave in roughly three days, and a full run takes about two weeks depending on the process. Each unit is built and inspected to IPC-WHMA-A-620 Class 3 and receives a full continuity and pinout test before it is packed. For the same construction in its general form, see the memory wire composite harness. Where the assembly has to survive continuous motion rather than hold a shape, our custom industrial robot wire harness is the better comparison, and where it should retract instead of stay put, look at a coiled retractable cable.

Frequently asked questions

Everything on this page is general guidance. Each cable is built and inspected to your drawing.