Crimping Machine Troubleshooting: Causes & Fixes

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Problems on this page:

Crimp height out of tolerance Pull-off force too low Strands cut or nicked Bell mouth or brush length wrong Insulation crimp not gripping Terminal feed jamming Crimp force monitor alarms Wire length wrong Applicators wearing out early

Crimp height out of tolerance

Hits OEE: Quality

Symptoms: Crimp height checks fail or drift during the run.

Applicator tooling worn

Check the crimper and anvil for wear and change the applicator at the stroke count the maker sets.

Crimp height adjustment moved

Reset the crimp height to the specification for the wire and terminal.

Wrong wire size for the terminal

Check the wire cross section against the terminal data sheet.

Terminal strip not feeding to the right position

Check the feed finger setting so the terminal sits centred on the anvil.

Prevention: Crimp height measured at start-up, after each applicator change and on a fixed schedule.

Pull-off force too low

Hits OEE: Quality

Symptoms: Pull tests fail and wires come out of the terminal.

Crimp height too high

Correct the crimp height first, since it decides the pull-off force.

Insulation caught in the wire crimp

Check the strip length so only bare strands sit in the wire crimp.

Strands cut or missing

Check the stripping blades and settings.

Wrong applicator for the terminal

Check the applicator number against the job.

Prevention: Pull test on samples at start-up and after each change.

Strands cut or nicked

Hits OEE: Quality

Symptoms: Inspection finds cut or nicked strands at the strip.

Stripping blades worn or set too deep

Replace worn blades and set the blade depth for the wire.

Wrong blade set for the wire size

Fit the blade set for this wire.

Wire not centred in the blades

Check the wire guides.

Insulation hardness different

Check the wire batch against its specification.

Prevention: Stripped ends checked under magnification at start-up.

Bell mouth or brush length wrong

Hits OEE: Quality

Symptoms: The bell mouth is missing or too large, or the strand ends stick out too far or not at all.

Applicator adjusted wrongly

Set the applicator as its data sheet shows.

Strip length wrong

Set the strip length for the terminal.

Wire position in the terminal varying

Check the wire stop and feed length.

Terminal position on the anvil off

Check the feed finger and strip guide.

Prevention: Crimp appearance checked against the terminal maker pictures.

Insulation crimp not gripping

Hits OEE: Quality

Symptoms: The insulation crimp is loose or pierces the insulation.

Insulation crimp height set wrong

Set the insulation crimp for the wire outside diameter.

Wire insulation thicker or thinner than expected

Check the wire specification.

Insulation tooling worn

Replace worn insulation tooling.

Strip length too long

Shorten the strip so insulation reaches the insulation crimp.

Prevention: Insulation crimp checked on samples.

Terminal feed jamming

Hits OEE: Availability

Symptoms: The terminal strip jams in the applicator and the machine stops.

Feed finger stroke or position wrong

Adjust the feed finger for the terminal pitch.

Terminal reel dragging or tangled

Check the reel holder and its brake.

Terminals bent on the reel

Check reels for damage before loading.

Carrier strip cutter blunt

Replace the strip cutter.

Prevention: Feed jams recorded by applicator.

Crimp force monitor alarms

Hits OEE: Quality

Symptoms: The crimp force monitor rejects good looking crimps, or misses bad ones.

Reference not taught after a change

Teach the reference again after every applicator, wire or terminal change.

Wire batch with different strands

Teach a new reference for the new wire batch.

Sensor or cable fault

Check the force sensor and its cable.

Tolerance band set wrong

Check the tolerance setting against the process specification.

Prevention: Monitor tested with known bad crimps at start-up.

Wire length wrong

Hits OEE: Quality

Symptoms: Cut wire lengths are outside the tolerance.

Feed rollers slipping

Clean the feed rollers and check their pressure.

Length encoder fault

Check the encoder against a measured length.

Wire straightener set wrong

Set the straightener for the wire.

Wire drum dragging

Check the wire payoff.

Prevention: Wire length measured at start-up.

Applicators wearing out early

Hits OEE: Availability

Symptoms: Applicators need repair well before their expected stroke count.

Stroke counts not recorded

Record strokes per applicator so wear can be planned.

Applicator not cleaned and lubricated

Clean and lubricate applicators as the maker sets.

Wrong applicator used for the terminal

Check applicator and terminal pairing.

Debris from stripping reaching the tooling

Keep the waste extraction working.

Prevention: Applicator stroke counts tracked in the maintenance system.

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

Stop the same fault coming back

Recurring crimping machine 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