Shearing Machine Troubleshooting: Causes & Fixes

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Problems on this page:

Burr on the cut edge Bow or twist in cut strips Cut size out of tolerance Blade chipping Hold-downs not clamping Slow or uneven stroke Parts out of square Stops from guards or light curtains Sheet sliding off the supports

Burr on the cut edge

Hits OEE: Quality

Symptoms: Cut edges have a heavy burr or a rolled edge.

Blade clearance too large for the thickness

Set the clearance for the thickness and material.

Blades dull

Turn or regrind the blades.

Clearance uneven along the blade

Check the clearance at several points and adjust.

Prevention: Clearance chart for thickness and material at the machine.

Bow or twist in cut strips

Hits OEE: Quality

Symptoms: Narrow strips come off the shear curved or twisted.

Rake angle too high for narrow strips

Reduce the rake angle where the machine allows.

Hold-downs not clamping evenly

Check the hold-down pressure and pads.

Clearance too large

Reduce the blade clearance.

Stress in the material

Check the sheet flatness before cutting.

Prevention: Rake settings recorded for narrow strip jobs.

Cut size out of tolerance

Hits OEE: Quality

Symptoms: Parts are too long or too short or vary along the cut.

Backgauge not calibrated

Calibrate the backgauge against a measured part.

Backgauge not parallel to the blade

Square the backgauge.

Sheet not pushed against the gauge

Check the sheet support and operator method.

Prevention: Backgauge calibration on the monthly PM.

Blade chipping

Hits OEE: Availability

Symptoms: Pieces break off the blade edge.

Material thicker or harder than the rating

Check the capacity chart for the material.

Clearance too tight

Set the clearance correctly.

Cutting short pieces always at the same blade section

Spread the work along the blade.

Prevention: Blade edges inspected weekly.

Hold-downs not clamping

Hits OEE: Quality

Symptoms: The sheet moves during the cut.

Hydraulic pressure low

Check the hold-down circuit pressure.

Hold-down pads worn

Replace the pads.

Valve fault

Check the hold-down valve.

Prevention: Hold-down function checked at start-up.

Slow or uneven stroke

Hits OEE: Availability

Symptoms: The beam moves slowly or one side lags.

Hydraulic oil low or hot

Check the oil level and the cooler.

Pump wear

Check the pump output.

Synchronisation fault between cylinders

Check the synchronisation system.

Prevention: Stroke time checked monthly.

Parts out of square

Hits OEE: Quality

Symptoms: Cut parts are not square at the corners.

Squaring arm out of alignment

Realign the squaring arm to the blade.

Sheet not held against the arm

Check the operator method and supports.

Backgauge skewed

Square the backgauge.

Prevention: Squareness checked on a test sheet monthly.

Stops from guards or light curtains

Hits OEE: Availability

Symptoms: The shear stops during production on a safety device.

Light curtain dirty or misaligned

Clean and align the curtain.

Guard switch loose

Fix the switch.

Sheet entering the protected zone

Check the work method and supports.

Prevention: Safety devices tested at each shift start; never bypassed.

Sheet sliding off the supports

Hits OEE: Availability

Symptoms: Large sheets slip or sag before the cut and need repositioning.

Front supports too short or too few

Fit support arms or ball transfer tables for large sheets.

Back supports or sheet catcher missing

Fit a back support so cut parts do not drop and twist.

Operator handling heavy sheets alone

Use lifting aids for large sheets.

Prevention: Sheet supports matched to the largest sheet run on the shear.

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

Related equipment guides: press brake · hydraulic press · laser cutter · plasma cutter · hydraulic system

Stop the same fault coming back

Recurring shearing 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