Cable Extrusion Line Troubleshooting: Causes & Fixes

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Problems on this page:

Insulation thickness out of tolerance Spark test failures Surface defects on the sheath Conductor problems at the payoff Cooling trough problems Take-up winding faults Long colour or size changes Printing or marking faults

Insulation thickness out of tolerance

Hits OEE: Quality

Symptoms: The insulation or sheath is too thin, too thick or off centre.

Extruder output varying

Check the melt pressure and screw speed, and the material feed to the hopper.

Line speed varying

Check the capstan and the speed control.

Crosshead tooling worn or not centred

Check the die and tip and the centring of the crosshead.

Diameter gauge or eccentricity gauge out of calibration

Check the gauges against a reference.

Prevention: Diameter and eccentricity recorded continuously and checked against the specification each reel.

Spark test failures

Hits OEE: Quality

Symptoms: The spark tester finds faults in the insulation.

Contamination or gels in the compound

Check the compound, the dryer and the hopper for contamination.

Moisture in the compound

Check the dryer temperature and time.

Thin spots from output surges

Check the extruder for surging.

Damage after extrusion

Check the cooling trough, guides and capstan for anything that scrapes the cable.

Prevention: Spark faults recorded per reel with their position.

Surface defects on the sheath

Hits OEE: Quality

Symptoms: The sheath shows lumps, rough patches or die lines.

Melt temperature wrong for the compound

Check the barrel and head temperatures against the recipe.

Die or tip damaged

Inspect the tooling and polish or replace it.

Degraded material hanging in the head

Purge and clean the crosshead.

Screen pack blocked

Change the screen pack.

Prevention: Surface inspected on each reel.

Conductor problems at the payoff

Hits OEE: Availability

Symptoms: The conductor breaks, tangles or feeds unevenly from the payoff.

Payoff tension wrong

Check the payoff brake or drive and the dancer.

Conductor damaged or kinked on the drum

Inspect incoming drums and record damaged ones for the supplier.

Preheater not set

Check the conductor preheater temperature for the compound and size.

Splices weak

Check the butt welding of conductor joints and test a sample weld.

Prevention: Payoff stops recorded per drum.

Cooling trough problems

Hits OEE: Quality

Symptoms: The cable is not cooled enough before the capstan, so the insulation deforms.

Water temperature too high

Check the chiller and the water returning to the trough.

Water flow too low

Check the pump, the strainer and the spray bars.

Trough too short for the line speed

Match the line speed to the cooling length.

Air pockets on the cable

Check the water level and the entry seals, so the cable stays fully under water.

Prevention: Cable temperature at the capstan checked each reel.

Take-up winding faults

Hits OEE: Availability

Symptoms: Reels are wound with crossovers or loose layers, or the take-up stops the line.

Traverse pitch or limits set wrong

Set the traverse pitch for the cable diameter and the limits for the reel flanges.

Take-up tension wrong

Check the take-up tension and the dancer.

Reel change sequence slow

Check the automatic reel change or the accumulator used during the change.

Reels damaged

Inspect reels and flanges before loading.

Prevention: Winding quality checked on each reel.

Long colour or size changes

Hits OEE: Performance

Symptoms: Colour and size changes take long and produce a lot of scrap cable.

Purging slow with the production compound

Use a purge compound and a set purge sequence for colour changes.

Next tooling not ready

Clean, measure and stage the next die and tip before the change.

Settings not stored per product

Store the temperatures, screw speed and line speed per product.

Start-up done by trial and error

Write a start-up sequence that ramps speed in set steps.

Prevention: Change time and scrap length recorded per change.

Printing or marking faults

Hits OEE: Quality

Symptoms: Marking on the cable is missing, smudged or at the wrong spacing.

Printer not synchronised with line speed

Check the encoder that feeds the line speed to the printer.

Ink not suited to the compound

Check the ink against the sheath material.

Cable surface wet at the printer

Dry the cable surface with air wipes before printing.

Print head dirty

Clean the print head on the interval the maker sets.

Prevention: Marking checked on each reel.

Guidance only. Always follow lockout/tagout and your site's safe-work procedures, and verify against OEM manuals before acting.

Related equipment guides: extruder · wire drawing machine · coil winding machine · chiller · resin dryer · pipe extrusion line

Stop the same fault coming back

Recurring cable extrusion line stops usually trace to a cause you cannot see by hand. The partner we recommend is Fabrico: it tracks OEE and downtime live from PLCs, IoT sensors or AI cameras; where cameras are fitted, the video of a stop sits next to its machine data so the cause can be reviewed; and a technician opens the work order from the stop in the same system. Data is hosted in the AWS EU region, and Fabrico and the company behind it hold ISO/IEC 27001, ISO/IEC 20000-1 and ISO 9001.

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Methods that cut recurring stops: the six big losses · root cause analysis · preventive vs predictive maintenance · TPM · SMED & changeover