Choosing Cable Glands for High-Flex Robotics Applications

High-flex cables are designed to withstand repeated movement, but cable life depends on more than the cable itself. In robotic and automated equipment, failures often occur where the cable enters a control cabinet, junction box, or machine enclosure.

At these entry points, the cable may be exposed to repeated bending, pulling, vibration, and torsion. If the cable gland does not provide enough strain relief or allows the cable to bend too sharply near the enclosure, stress becomes concentrated in a very small area. Over time, this can damage the conductor, insulation, or shielding even when the cable is rated for millions of flex cycles.

Cable glands therefore play an important role in robotic cable management. They need to secure the cable without restricting necessary movement, maintain the required sealing level, and provide suitable strain relief within the limited space available around the machine or cabinet.

At Hoonsun, we design cable glands for demanding automation applications where movement, vibration, space constraints, and environmental protection all need to be considered together. Selecting the right gland starts with understanding how the cable moves, how much space is available, and what level of sealing and mechanical protection the application requires.

What Happens Inside a Robot Control Cabinet

A robot control cabinet packs servo drives, a PLC, safety relays, filters, and power supplies into a surprisingly small enclosure. That means dense bundles of power cable, signal cable, and network cable entering through the bottom or side panels, all sharing space with fans that move warm air through the cabinet.

The entry point is the weak spot. The robot arm moves constantly, and that movement travels back along the cable and into the gland. High-flex cable jackets are thin and the conductors are finely stranded, so a gland that bites too hard can pinch the jacket or cut strands over time. A gland that grips too loosely lets the cable chafe against the panel edge, which does the same damage in a different way.

Our nylon anti-bending cable gland is designed to reduce stress where the cable exits the enclosure. Instead of gripping the cable over a short section, the extended flexible tail supports a longer length of cable and helps distribute bending force more gradually.

This is particularly important in robotic and automated equipment, where cables may bend repeatedly during every operating cycle. By reducing the concentration of stress near the gland entry, the design can help limit premature wear on the cable jacket and conductors.

The gland also provides IP68 sealing to protect the enclosure against dust and water ingress. For automated production lines, this adds another layer of protection in environments where equipment may be exposed to dust, moisture, or routine washdown.

In applications that combine frequent cable movement with demanding environmental conditions, the cable gland needs to provide both mechanical support and reliable sealing.

Where Cable Glands Matter in a Robotic Cell

Cable entry points appear in several places in a typical robotic cell, and each one stresses the fitting differently. The right robotics cable gland for one position can be the wrong one for another.

Robot arm and end effector

Cables running from the base of the arm up to the wrist and end effector flex with every move. These are the hardest working cables in the cell, and the glands at the base and wrist have to hold them without restricting motion. An anti-bending design pays for itself here, because a short, stiff gland forces the cable into a tight bend right at the mouth of the fitting. That bend is where high-flex cable eventually breaks.

Control cabinet entries

The main cabinet is where power, signal, and network cables come together, and where most of them change direction. Every cable needs its own gland sized to its actual diameter, with the right thread for the panel hole and a locknut that fits the space inside. This is also where spare capacity matters. Robotic cells get modified over time, and a gland panel with no room for one more cable forces a rework later.

Junction boxes along the cell

Sensor junction boxes, safety light curtain terminals, and camera boxes sit at the edges of the cell, often in positions that are hard to reach and exposed to coolant mist or washdown. Glands here need dependable sealing more than anything else. IP68 or IP69K sealing per IEC 60529 keeps the boxes dry, and a properly fitted gland gives the termination inside a stable cable that does not pull on the terminals when the machine runs.

Key Factors When Selecting Cable Glands for Robotic Applications

When selecting a cable gland for robotic or automated equipment, the choice should be based on how the cable moves, the surrounding environment, and the electrical requirements of the installation. The same basic considerations apply whether the application is a single robot cell or a larger automated production line.

• Bend radius and flex life: The gland should support the cable without forcing it into a tight bend at the enclosure entry. An extended anti-bending section can help maintain a smoother bend radius and reduce localized stress. Flex-life requirements should always be checked against the cable construction and the gland design.
• Nylon glands are lightweight, corrosion-resistant, and suitable for many general automation applications. Brass provides greater mechanical strength and is commonly used where EMC grounding is required, while stainless steel is better suited to corrosive or demanding industrial environments.
• IP rating: The required protection level should reflect the actual operating environment. IP68 is commonly used where dust and water ingress must be controlled, while applications exposed to high-pressure or high-temperature washdown may require a higher level of protection, such as IP69K where applicable.
• EMC shielding: Shielded cables require a gland that can maintain reliable electrical contact with the cable braid or screen. Metal EMC glands with 360-degree shield contact are typically used for this purpose. Standard nylon glands do not provide the same grounding function unless specifically designed with EMC components.
• Thread type and installation space: Metric, NPT, and PG threads are not interchangeable, so the gland thread must match the enclosure entry. Locknut clearance, panel thickness, and the available installation space should also be confirmed before final selection.

A suitable cable gland should do more than seal the enclosure. In robotic applications, it also needs to manage cable movement, reduce mechanical stress, and maintain reliable electrical and environmental protection over repeated operating cycles.

Choosing the Right Cable Gland for High-Flex Cables

No single gland style covers every entry point in a robot cell. Here is the short version of how we split the work.

Gland Type	Best For	Key Point
Nylon anti‑bending gland	Robot arms, wrist cables, anywhere the cable moves continuously	Long guide spreads bending stress and protects flex life
90 degree brass gland	Tight corners where the cable must turn right after entry	Redirects the cable without forcing a sharp bend at the gland mouth
Zinc alloy hose fitting	Cable runs from cabinet to machine sections	Pairs with flexible conduit for mechanical protection along long paths

The 90 degree brass gland is a favorite in control cabinet builds, because panel space is always at a premium and cables rarely enter straight. The zinc alloy hose joint covers the runs between the cabinet and the machine base, where conduit keeps cables out of pinch points and away from moving parts. Exact dimensions, thread options, and sealing ratings vary by model, so check the datasheet before ordering.

Installation Tips We Give Every Automation Customer

Most gland failures we see in robotic cells are installation problems, not product problems. These four habits prevent the majority of them.

• Leave a service loop. Pulling cable tight at the gland turns every small movement of the machine into full tension on the termination.
• Tighten to the recommended torque, not maximum. Over-tightening a nylon gland can crack the body or crush fine-stranded high-flex cable. Torque values are listed per size in the datasheet.
• Match the inner seal to the actual cable diameter. A seal that is too large leaks and lets the cable move, and one that is too small crushes the jacket.
• Route the cable straight out of the gland for at least the length of the guide. Forcing an immediate bend at the mouth defeats the anti-bending design.

FAQ

Q: Can standard nylon cable glands be used for continuous movement?

A: Yes, but anti-bending cable glands are better for cables that flex repeatedly. Their extended strain-relief section reduces stress at the cable entry and helps improve cable life.

Q: When should metal cable glands be used for EMC shielding?

A: Use a metal EMC cable gland when a shielded cable needs to maintain grounding through the enclosure. A 360° shield contact provides a reliable path between the cable braid and the panel.

Q: What IP rating is recommended for robotic applications?

A: IP68 is suitable for many robotic cells exposed to dust or moisture. For high-pressure washdown or harsh cleaning environments, consider IP69 or IP69K-rated glands, depending on the applicable standard and equipment requirements.

Selecting a cable gland for robotics starts with three things: how the cable moves, the environment it operates in, and the cable construction itself. Getting those details right helps reduce stress at the entry point, maintain sealing performance, and avoid premature cable failure.

If you are designing or troubleshooting a robotic cell, Hoonsun can help review the cable entry requirements and recommend a suitable gland. Share the cable diameter, movement path, installation space, and washdown conditions with our team, and we can help identify the right option for the application.