Troubleshooting Chart

1. Feeding unit
TroublePossible causeRemedy
Sheets don't feedFeed gate is too tightCheck clearance with sample sheet from order and make adjustment accordingly
Rear panel is too tightCheck setting against sheet size and/or manufacturing diagram
Too many sheets in feederReduce quantity in feeder
Moist sheetsCheck sheets for moisture content.
Double feeding of sheetsFront gate is too highReset gate to just allow one sheet through
Sheets crushedFeed roll is too lowAdjust clearance in accordance with sheet thickness
Crushed at thecorrugatorCheck thickness of sheets received from corrugator
Feed rolls are out of parallelMake sure feed rolls are parallel and are not loose on either end
Sheets slippingWorn feed rollCheck feed roll to see if it has hardened and has become too smooth to grip sheet firmly without crushing
Sheet size is too small.Check sheet size to see if it is below the minimum sheet size of machine
Excessive bendingCheck the bending degree of sheet and pick out too bended ones
Improperly calibrated indicatorCheck dial and instrument panel on operator's side of machine
Variable printing and slotting resultsImproper feedingSee "Sheets don't feed" and "Sheets slipping" parts above
Poor printingPoor printingSee "Sheets crushed"
TroublePossible causeRemedy
2. Printing unit (1)
Insufficient InkNo ink in ink tankReplenish ink tank
Clogged hosesRemove and clean
Air pressure lossCheck and fix air circuit
Ink bubblingAdd antifoaming agent to ink
Electricity failureCheck and fix electric circuit
Ink circulating system filter cloggedRemove and clean filter
Pump not turned onEnsure that system switches are activated and press Reset button
Impression roll does not move up or downAir solenoid valve defectiveReplace solenoid valve
Pneumatic lines clogged with oil / waterRemove blockage, replace lines if necessary
Leaky pneumatic linesRepair or replace
Air supply not activatedEnsure that air supply valves are open
Jam-up in printing unitLoose liner on sheetReplace sheet
Loose sheet guideIf sheets are slightly warped, a loose sheet guide may cause snags, so the guide needs to be tightened
Sheet liner sticking to printing plateThis will happen if machine is stopped during feeding, so remove jammed board and carefully clean printing plate
Loss of registerMisplaced printing plateRelocate printing plate
Stretched or loose printing plateRepair or replace
Loose or worn gears in phase shifter or main driveRepair or replace
Loose axle sleeveReplace
3. Printing unit (2)
TroublePossible causeRemedy
Loss of register (continued)Insufficient pressure on pull rollsAdjust roll clearance
Worn upper pull rollReplace
Printing out of registrationInsufficient sheet controlAdd pull bands
Print not centeredPrinting blanket not centeredImproperly scribed plate centerline. Lateral setting of print cylinder not returned to "0" after previous order
Ink return flow sluggish or stops during runInk return pump clogged with paper dustDismantle and clean return pump (must be done once a week)
Ink viscosity drops and/or ink level increasesWater getting into ink, automatic wash-up device turned onCheck water shut-off valve and cylinder, increase air supply
Ink overflowsInk flow is too greatInk return flow should visually be controlled below than 3/8", and supply capacity is greater than return capability
Ink return pump cloggedDismantle return pump and clean
Ink throws at high speed on print cylinderInk flow is too greatCut down ink flow
Wash up water runs sluggishly or stops in return lineInk return pump clogged with paper dustDismantle return pump and clean
Insufficient ink supplyNo ink in tankFill ink in tank
Clogged hosesRemove and clean
Ink bubblingAdd antifoaming agent to ink
Ink filter cloggedRemove and clean or replace
4. Slotting unit
TroublePossible causeRemedy
Slotting out of registrationImproperly sheet feedingSee "Feeding unit"
Less pressure on sheet when transportingDecrease clearance between guide rolls, or pre-creasing wheels, or creasing wheels
Seriously worn slotting bladeReplace the slotting blade
Loose slotting bladeTighten slotting blade
Incorrect phase of slotting bladeAdjust phase
The upper and down shafts of pre-creasing wheels or creasing wheels are not parallelAdjust shafts to be parallel
Slotting not uniform, coarse edge, or sheet crushedSeriously worn slotting bladeAdd pull bands to blade carrier
The driving chain for lateral movement of blade carrier is looseCheck and fasten the chain
The front and back slotting blades are not in a lineAdjust the blades and make them in a line
Less pressure of creasing wheelsDecrease the clearance between the creasing wheels
Poor quality sheets, such as dryness and low fiber proportionUse high quality sheets
Sheets crushed at the corrugatorCheck sheets for damage as received fromcorrugator
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