Uncoiler Fault Triage
A start failure, stop failure, false sensor trigger, loose coil, mandrel problem and hydraulic symptom require different evidence. Do not begin by changing settings or replacing parts.
Stop Before Diagnosis When the Condition Is Unsafe
Use the stop response defined by the machine instructions and site risk assessment when the coil loosens or telescopes, strip enters an unsafe area, the decoiler cannot stop as commanded, a guard or interlock is ineffective, unexpected motion occurs, hydraulic leakage appears, or smoke, burning odor, abnormal noise, vibration, heat or structural movement is observed.
Capture the Symptom Before Resetting the Line
- Machine state
Model, serial number, options, operating mode and indicated commands. - Coil state
Material, width, thickness, weight, ID, OD, winding and visible condition. - Event sequence
Command or downstream condition, alarm, first abnormal behavior and stop. - Recent change
Coil, setup, maintenance, wiring, parameter, component or production change.
Record the sensor state, loop shape, coil behavior, strip path, noise, vibration, heat, leakage and visible damage. Safe photos or video and a time sequence help distinguish a repeatable machine fault from material, setup, interface, power or downstream-demand changes.
Select the Correct Symptom Path
| Observed symptom | First evidence to capture | Primary page |
|---|---|---|
| Does not start or rotate | Mode, stops, alarms, interlocks, demand and loop request | General no-start guide |
| Does not stop / overruns | Sensor method and state, stop request, coast and downstream demand | Auto-stop diagnosis |
| Intermittent or false sensing | Sensor type, surface, film, reflectivity, contamination and mounting | Sensing and stop issues |
| Loose coil / telescoping | Retention, winding, drive/brake response, loop and downstream pull | Loose or bulk material |
| Mandrel expand/release fault | Coil ID, command, support or coil-car state, drift and leakage | Hydraulic misoperation |
| Irregular hydraulic motion | Reservoir, leak, hose, noise, heat, foaming and recent service | Possible air ingress |
Diagnose a Decoiler That Does Not Start or Rotate
Confirm only operator-visible prerequisites allowed by the supplied instructions: selected mode, released stop or alarm state, guard and interlock state, downstream demand, loop-control request and obvious external damage. Do not open the control enclosure or test energized components unless the work is assigned to qualified personnel.
Diagnose Automatic Stop, Overrun and Sensor Faults
Separate the event
Did the control never receive a stop request, stop late, or stop the motor while coil inertia continued?
Identify the sensor
Record contact arm, photoelectric, ultrasonic, proximity or other device and its indicated state.
Record the material
Surface, coating, film, reflectivity and loop geometry can change sensing behavior.
Protect the evidence
Do not copy timer, relay, VFD, brake or sensor settings from another machine.
Stop production before the loop or loose strip becomes a collision or access hazard. Never defeat the sensor or hold a sensing device manually to keep automatic production running.
Diagnose Loose Coil, Overrun and Telescoping
These symptoms may involve coil condition, insufficient retention, drive or brake response, acceleration and deceleration, loop demand, downstream pull, centerline, mandrel interface, or support and press-arm configuration. Secure the condition under the supplied procedure and preserve the observed sequence.
Diagnose Mandrel and Hydraulic Motion Problems
Record coil ID, mandrel state, command indication, support-arm or coil-car position, visible interference, drift, leakage and recent service work. Similar irregular-motion symptoms can come from contamination, possible air ingress, suction-side problems, restrictions, component wear, load or control faults.
- Do not enter the interface
Never work between a coil and mandrel under unsupported or unknown load conditions. - Do not loosen connections
Bleeding and fitting work require the approved hydraulic service method. - Do not change pressure
Use the supplied schematic, instrument and authorized procedure. - Do not repeat motion blindly
Repeated cycling can worsen leakage, interference or load instability.
Separate Mechanical, Surface and Line-Interface Symptoms
| Symptom | Evidence | Boundary |
|---|---|---|
| Noise, vibration or heat | Location, timing, direction, loaded/unloaded state and recent change | May span bearing, drive, brake, coil, motor, reducer or alignment |
| Scratch or edge damage | First contact point, surface, burr, guides, loop and protective film | Separate decoiler from straightener, feeder, die and handling contact |
| Coil-car travel/lift fault | Car position, load, rail, limits, obstruction, leak and alarm | Use coil-car hydraulic, mechanical and control documents |
| Downstream-demand mismatch | Signal state, material pull, line mode, speed stage and timing | Diagnose the full line, not the decoiler alone |
Prepare a Service Handoff Package
Send the machine and coil identity, exact symptom, event sequence, operating mode, alarms, sensor and loop observations, recent changes, safe photos or video, applicable drawings, checks already authorized and completed, and the current isolation or production restriction.
- Identity
Model, serial, options, coil, material and job. - Sequence
Last normal state, trigger, abnormal response and stop. - Evidence
Alarms, I/O or sensor state, loop, photos, video and recent changes. - Current control
Isolation, restriction, hold point and responsible person.
What This Troubleshooting Router Does Not Authorize
Frequently Asked Troubleshooting Questions
Should the first step be resetting the alarm?
Preserve the alarm, mode, sensor and event evidence first. A reset can remove information and does not resolve the cause.
Can a timer or sensor setting be copied from another decoiler?
No. The sensor, material, control logic, drive and line configuration may differ. Use the supplied schematic and approved commissioning record.
When should technical support be contacted?
Escalate immediately for unsafe motion, loose coil, ineffective safeguards, leakage, smoke, abnormal heat or structural behavior, and whenever diagnosis exceeds the authorized role.
Related HENLI Resources
Send the Fault Evidence Before Changing the Machine
Provide the model and serial number, coil and material data, operating mode, alarm history, sensor and loop state, event sequence, recent changes and safe photos or video. HENLI can route the case to the appropriate technical review.
