Specialized in Manufacturing Corrugated Carton Printing Machine & Solutions Since 1995
1. Feeding Unit | ||
Trouble | Possible causes | Remedy |
Sheets don't feed | Feed gate is too tight |
Check clearance with sample sheet from order and make adjustment accordingly |
Rear panel is too tight |
Check setting against sheet size and/or manufacturing diagram |
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Too many sheets in feeder | Reduce quantity in feeder | |
Moist sheets | Check sheets for moisture content. | |
Double feeding of sheets | Front gate is too high | Reset gate to just allow one sheet through |
Sheets crushed | Feed roll is too low | Adjust clearance in accordance with sheet thickness |
Crushed at thecorrugator | Check thickness of sheets received from corrugator | |
Feed rolls are out of parallel | Make sure feed rolls are parallel and are not loose on either end | |
Sheets slipping | Worn feed roll |
Check 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 |
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Excessive bending | Check the bending degree of sheet and pick out too bended ones | |
Improperly calibrated indicator | Check dial and instrument panel on operator's side of machine | |
Variable printing and slotting results | Improper feeding | See "Sheets don't feed" and "Sheets slipping" parts above |
Poor printing | Poor printing | See "Sheets crushed" |
2. Printing Unit |
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Trouble | Possible causes | Remedy |
Insufficient Ink | No ink in ink tank | Replenish ink tank |
Clogged hoses | Remove and clean | |
Air pressure loss | Check and fix air circuit | |
Ink bubbling | Add antifoaming agent to ink | |
Electricity failure | Check and fix electric circuit | |
Ink circulating system filter clogged | Remove and clean filter | |
Pump not turned on | Ensure that system switches are activated and press Reset button | |
Impression roll does not move up or down | Air solenoid valve defective | Replace solenoid valve |
Pneumatic lines clogged with oil / water | Remove blockage, replace lines if necessary | |
Leaky pneumatic lines | Repair or replace | |
Air supply not activated | Ensure that air supply valves are open | |
Jam-up in printing unit | Loose liner on sheet | Replace sheet |
Loose sheet guide |
If sheets are slightly warped, a loose sheet guide may cause snags, so the guide needs to be tightened |
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Sheet liner sticking to printing plate |
This will happen if machine is stopped during feeding, so remove jammed board and carefully clean printing plate |
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Loss of register | Misplaced printing plate | Relocate printing plate |
Stretched or loose printing plate | Repair or replace | |
Loose or worn gears in phase shifter or main drive | Repair or replace | |
Loose axle sleeve | Replace | |
Insufficient pressure on pull rolls | Adjust roll clearance | |
Worn upper pull roll | Replace | |
Printing out of registration | Insufficient sheet control | Add pull bands |
Print not centered | Printing blanket not centered |
Improperly scribed plate centerline. Lateral setting of print cylinder not returned to "0" after previous order |
Ink return flow sluggish or stops during run | Ink return pump clogged with paper dust | Dismantle and clean return pump (must be done once a week) |
Ink viscosity drops and/or ink level increases | Water getting into ink, automatic wash-up device turned on | Check water shut-off valve and cylinder, increase air supply |
Ink overflows | Ink flow is too great |
Ink return flow should visually be controlled below than 3/8", and supply capacity is greater than return capability |
Ink return pump clogged | Dismantle return pump and clean | |
Ink throws at high speed on print cylinder | Ink flow is too great | Cut down ink flow |
Wash up water runs sluggishly or stops in return line | Ink return pump clogged with paper dust | Dismantle return pump and clean |
Insufficient ink supply | No ink in tank | Fill ink in tank |
Clogged hoses | Remove and clean | |
Ink bubbling | Add antifoaming agent to ink | |
Ink filter clogged | Remove and clean or replace | |
3. Slotting Unit |
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Trouble | Possiblecauses | Remedy |
Slotting out of registration | Improperly sheet feeding | See "Feeding unit" |
Less pressure on sheet when transporting |
Decrease clearance between guide rolls, or pre-creasing wheels, or creasing wheels |
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Seriously worn slotting blade | Replace the slotting blade | |
Loose slotting blade | Tighten slotting blade | |
Incorrect phase of slotting blade | Adjust phase | |
The upper and down shafts of pre-creasing wheels or creasing wheels are not parallel | Adjust shafts to be parallel | |
Slotting not uniform, coarse edge, or sheet crushed | Seriously worn slotting blade | Add pull bands to blade carrier |
The driving chain for lateral movement of blade carrier is loose | Check and fasten the chain | |
The front and back slotting blades are not in a line | Adjust the blades and make them in a line | |
Less pressure of creasing wheels | Decrease the clearance between the creasing wheels | |
Poor quality sheets, such as dryness and low fiber proportion | Use high quality sheets | |
Sheets crushed at the corrugator | Check sheets for damage as received fromcorrugator |