By TEBAOFLEX Jyen. Originally published on July 28, 2026.
A PUR jacket describes the outside of a servo cable, not its complete construction. The power-core insulation, fillers, shields, lay lengths and conductor design all affect performance. “TPE/PUR” and “PVC/PUR” are useful material descriptions, but neither independently proves ten million cycles or establishes a safe bend radius.
Compare the inside as well as the jacket
- Identify the exact core compound rather than treating every thermoplastic elastomer as the same material.
- Check conductor construction, power and brake-pair layout, shielding, inner bedding and outer-jacket compatibility.
- Obtain the moving-operation temperature range and bend radius for the ordered size; fixed-installation limits are different.
- Match environmental tests to the actual oils, coolants, cleaning agents and exposure temperatures.
Plasticizer migration, chemical attack, internal abrasion and fatigue are possible failure mechanisms, but their occurrence depends on formulation and service conditions. It is not defensible to predict that all PVC-insulated cables fail at a fixed cycle count or that all TPE compounds remain unchanged with age.
Make a cycle-life claim reproducible
A useful endurance report identifies the specimen, cable diameter, bend radius, stroke, speed, acceleration, temperature, carrier layout, applied tension and definition of a cycle. It also states the number of specimens, monitoring method and failure criteria. A result at one radius or temperature cannot be transferred automatically to another installation.
igus ties its own cable-life claims to application parameters such as bend radius, temperature, travel and movement type. That illustrates why a conditional qualification is more informative than a standalone “10 million cycles” label; it does not substantiate any TEBAOFLEX endurance claim.
Electrical checks for servo duty
Compare voltage ratings, permitted drive-cable length, insulation system, protective earth and shield termination with the drive manual. Lower measured capacitance can reduce capacitive charging current under comparable switching conditions, but the current also depends on cable length and waveform. It does not by itself authorize a longer motor lead or prove lower drive temperature.
Brake and feedback circuits need their own voltage, shielding and compatibility checks. An unscreened cable should be selected only when the complete equipment design permits it; a low nominal circuit voltage does not remove EMC requirements.
Use the carrier layout as part of qualification
Avoid twisted installation, crowding and tensile loading in the moving bend. Select separation, clearances and strain relief using the cable and carrier manufacturers’ instructions. A material change cannot compensate for a pinched or incorrectly routed cable.
What to put in the purchase order
- Exact cable configuration and finished diameter, insulation and sheath compounds, voltage and temperature ratings.
- Motion profile and required life with a defined cycle; radius, travel, loading and environmental conditions.
- Before/after checks for conductor and shield continuity, insulation condition and any applicable transmission parameters.
- Evidence for claimed approvals, including the actual AWM style and manufacturer file where applicable; AWM recognition is not a flex-life certificate.
Sources and scope
igus: application-conditioned cable-life qualification
igus: carrier filling and bend-radius guidance
UL: AWM component qualification
These references explain the relevant methods or manufacturer guidance. They do not certify a TEBAOFLEX product or establish results for a supplied batch.
Discuss your specification
For a project-specific cable specification, send the duty, installation drawing and required acceptance criteria to TEBAOFLEX. WhatsApp: +86 185 9591 3361. Request documented product ratings and test evidence before approval.