A safe routing guide for poor flatness, tracking, surface marks, vibration, jams and electrical faults.
First Record What Changed
Capture the model, material lot, grade, thickness, width, incoming coil condition, recipe, speed, line state, alarm code and sample location. Note whether the problem began after a coil change, setup change, maintenance event, collision or gradual wear. A photo of the defect and a marked sample are often more useful than a general description.
Symptom Router
| Symptom | Safe first checks | Do not assume |
|---|---|---|
| Coil set remains | Incoming curvature, material strength/thickness, recipe and entry/exit orientation | More pressure is always the answer |
| Reverse curl/over-correction | Recorded setting, direction of approach and exit condition | The feeder caused the curvature |
| Edge wave/center buckle | Incoming profile, width, side-to-side setting, roll support and measurement | One-side adjustment is approved |
| Strip tracks sideways | Coil centering, line center, guides, unequal position and upstream pull | The leveler alone controls tracking |
| Repeating surface marks | Mark pitch, roll circumference, contamination, pickup and material debris | More lubricant will remove damage |
| Jam or buckling | Stop, isolate, inspect path/loop/leading edge and verify line sequence | Reversing under load is safe |
| Noise/vibration/heat | Stop criteria, load, lubrication, loose parts, bearings/gears and recent work | It is normal because the material is thick |
| Drive/VFD/sensor alarm | Record exact code and operating state; check documented connections and interlocks | Resetting repeatedly fixes the cause |
Separate Material, Machine and Line Causes
Lot strength, thickness, width, camber, coil set, crossbow, surface contamination and burr direction.
Recipe, roll condition, parallelism, support, drive, lubrication, wear and interlocks.
Decoiler containment, brake/tension behaviour, loop geometry, guides and synchronization.
Feeder pull, die pilots, press timing, cut length, sample support and measurement repeatability.
Use a Controlled Test Strip
After safe inspection, return to a known reference or approved starting point. Run a short representative sample at a controlled speed, mark direction and sides, measure the defined defects, then change one variable at a time. Record the response. Stop if the machine binds, load rises abnormally, an interlock fails or the response is inconsistent.
When to Escalate
- Visible roll scoring, chipped teeth, bearing heat, abnormal vibration or structural damage;
- Repeated drive, VFD, encoder, sensor or safety-interlock faults;
- Unknown machine range or material outside the approved envelope;
- Required access behind guards or any exposure to stored energy;
- Flatness or surface requirement cannot be demonstrated with the current measurement method.
Related HENLI Resources
Controlled test-strip method.Open-Type Maintenance
Safe roll access and cleaning.Leveler Fundamentals
Confirm the process and boundary.
Frequently Asked Questions
Should I increase pressure when material is not flat?
Not automatically. Identify the defect, confirm material data and settings, then use a controlled sample. Excess correction can create reverse curl, marks or overload.
Can a feeder create a leveling defect?
Feeder pull, misalignment or line timing can affect strip behaviour, but feeder pitch and material shape are separate responsibilities. Isolate the line sections before assigning the cause.
Can I reset a recurring VFD alarm?
Record the code and state, then follow the drive and machine documentation. Repeated resetting can hide an electrical, load, cooling or mechanical problem.
Send a Useful Troubleshooting Record
Include the model, serial number, material data, recipe, alarm code, marked sample and photos of the line state.
