Problems on this page:
Board warping
Hits OEE: Quality
Symptoms: Sheets curl up or down at the stacker, or flatten badly in the converting machines later.
Heat and moisture uneven between the two liners
Balance the preheater wrap on the top and bottom liners so both reach the glue at a similar temperature and moisture.
More glue on one side than the other
Check the glue gaps and the condition of the applicator and metering rolls on each glue unit.
Paper moisture varying between reels
Check incoming reel moisture and run reels with similar moisture together where you can.
Board not cooled evenly after the double backer
Check the double backer hot plate settings and the cooling section.
Prevention: Warp checked at the stacker for each order, with the corrections that worked recorded per grade.
Weak bond or delamination
Hits OEE: Quality
Symptoms: Liners peel away from the flutes by hand or in the bond test.
Glue gap too small for the flute
Set the glue gap for the flute profile and check it across the full width.
Starch glue gel point or viscosity wrong
Check the glue in the starch kitchen against its recipe and test the gel point.
Not enough heat at the glue line
Check the steam pressure to the heated rolls and the preheater wrap.
Line speed too high for the paper weight
Reduce speed for heavy papers until the bond test passes.
Prevention: Bond strength tested on each order and trended per grade.
Washboarding
Hits OEE: Quality
Symptoms: The outer liner shows the flute pattern as ripples, which spoils print.
Too much glue applied
Reduce the glue gap to the lowest setting that still passes the bond test.
Liner too light for the flute size
Check the paper specification with the customer for print grades.
Too much pressure in the double backer
Check the pressure roll or belt settings.
Glue too thin
Check the glue viscosity and solids content.
Prevention: Surface checked on every order for printing.
Crushed or uneven flutes
Hits OEE: Quality
Symptoms: Board caliper is low or varies across the sheet, and boxes lose strength.
Pressure roll gap set too tight
Set the pressure roll gap for the paper and flute.
Flute rolls worn
Measure the flute rolls and plan regrinding or replacement when worn.
Belt or roll pressure too high in the double backer
Reduce the pressure in the double backer.
Paper too dry and brittle
Check paper moisture and preheating.
Prevention: Caliper measured across the width on each order.
Splice failures
Hits OEE: Availability
Symptoms: The splicer misses a splice or the splice breaks in the machine, causing a web break.
Wrong splice tape for the paper
Use the tape the splicer maker specifies for the paper grade.
New reel end prepared incorrectly
Prepare the reel end and tape exactly as the splice procedure shows.
Splicer timing or settings off
Check the splicer settings against the maker values.
Reel brake tension wrong
Check the reel brakes so tension is steady through the splice.
Prevention: Splice failures recorded by cause and reel position.
Glue viscosity drifting
Hits OEE: Quality
Symptoms: Viscosity readings at the glue units change through the shift, and bonding changes with them.
Glue temperature changing in storage or the lines
Keep the storage and supply temperature steady.
Starch kitchen dosing wrong
Check the kitchen dosing of starch, caustic and borax against the recipe.
Glue kept in circulation too long
Use glue within the time limit set in the recipe.
Water added at the machine
Make corrections only through the starch kitchen, not with water at the glue unit.
Prevention: Viscosity measured at set times and recorded.
Rough slits or cracked score lines
Hits OEE: Quality
Symptoms: Sheet edges are ragged, or score lines crack when the box is folded.
Slitter knives dull
Sharpen or replace the knives on a fixed schedule.
Score settings wrong for the board grade
Set scoring depth and profile for the grade.
Board too dry
Check board moisture leaving the double backer.
Slitter scorer heads misaligned
Check the alignment of the heads and anvils.
Prevention: Edges and scores checked at the stacker on each order.
Heated rolls losing temperature
Hits OEE: Availability
Symptoms: Preheater or single facer roll temperatures fall and the bond weakens.
Steam traps failed
Test the traps on the heated rolls and replace failed ones.
Siphon pipe inside the roll broken or loose
Have the siphons inspected during a planned stop.
Steam pressure low
Check the steam supply from the boiler; steam lines and hot rolls need guarding, and work on them needs a permit.
Condensate not draining back
Check the condensate return line and its pumps.
Prevention: Roll surface temperatures logged at the start of each shift.
Blisters in the board
Hits OEE: Quality
Symptoms: Bubbles or loose patches appear between liner and flute.
Moisture trapped at the glue line
Check paper moisture and preheating so water can escape before bonding.
Glue lines uneven across the width
Check the applicator rolls for wear and dried glue.
Too much glue
Reduce the glue gap.
Line speed changing often
Keep the speed steady, since bonding settings are set for a speed range.
Prevention: Board checked for blisters on each order.
Guidance only. Always follow lockout/tagout and your site's safe-work procedures, and verify against OEM manuals before acting.
Related equipment guides: steam boiler · slitter rewinder · die cutter · flexo press · case erector
Stop the same fault coming back
Recurring corrugator 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.
Book a Fabrico demo
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Related tools: full troubleshooting directory · OEE calculator · downtime cost · MTBF / MTTR · glossary
Methods that cut recurring stops: the six big losses · root cause analysis · preventive vs predictive maintenance · TPM · SMED & changeover