Torsion cables for industrial robots: not every axis needs the same cable
A six-axis articulated robot is not a uniform machine. Each axis has its own kinematics, angular travel and load profile. Using the same cable on every axis leads to two opposite errors: it over-engineers where it is not needed, adding weight, stiffness and cost, and under-engineers where stress is highest, causing premature failure.
MOTIONROBOTLINE starts from this observation: a construction matched to the torsion level of each axis, not a single oversized solution.
Three families, three torsion levels. ROBOTLINE 90 (90/m, over 5 million declared cycles) is designed for axes A1A3, base, shoulder and elbow, where torsion exists but is limited. ROBOTLINE 180 (180/m, over 7 million cycles) covers axes up to A4, with compound kinematics and simultaneous motion. ROBOTLINE 360 (360/m, over 10 million cycles) is designed for axis 6, the wrist, where rotation is continuous and often without an effective end stop: this is where standard cables fail first. All three operate from -40 C to +90 C and are UL AWM.
Construction. The logic is shared: Class 6 extra-flexible copper conductors to IEC 60228 with anti-torsion geometry, XL-PE insulation, high-resistance PUR jacket. The differences lie in the details that matter: ROBOTLINE 180 has a reduced lay length and an anti-spatter PUR formulation for welding; ROBOTLINE 360 has a symmetrical anti-torsion geometry and a PUR HT jacket with anti-fatigue additives. The Motion EM-Torsion Mesh Shield, optional on the 90 and 180 and integrated in the shielded 360, maintains signal integrity after millions of torsion cycles.
Hybrid OCT configurations. ROBOTLINE is available in One Cable Technology configurations that combine power, control signals and impedance-controlled data pairs in a single cable. Data pairs reach 100 MHz even under torsion and support EtherCAT, PROFINET, EnDat and HIPERFACE DSL. Fewer cables on the robot mean fewer connectors, fewer failure points and less weight on the arm. The torsion characteristics apply to the MOTIONSERVO, MOTIONFEEDBACK, MOTIONHYBRID, MOTIONBUS and MOTIONSTANDARD families.
A system decision. For an OEM, the platform makes it possible to cable the entire robot with one supplier and axis-specific constructions. Where the project requires standardisation, ROBOTLINE 360 can be used on all axes; where weight, cost and footprint come first, the 90 + 180 + 360 combination remains the optimal choice.
At installation. Observe the minimum bending radii in the data sheets, use floating clamps that do not twist the cable at fixed points, check that the cable is not pre-twisted when laid, and leave enough length to absorb movement.
Our engineering team returns a preliminary assessment within 2 working days. Have ready the robot type and brand, the axes involved, the torsion profile and estimated daily cycles, the required electrical function and the installation environment.
