Folder-gluer problems: causes and fixes
18 Folder-gluer problems in offset printing and finishing: symptoms, probable causes, step-by-step fixes and prevention.
Folder-gluer · TPG-255
Flap not bonding with white glue (PVA/cold glue)
Boxes opening at erection or filling; glue peeling cleanly off the surface
Folder-gluer · TPG-256
Hotmelt not bonding (cooling before closure)
Hotmelt bead solidifying without grabbing the other face; peels off like plastic
Folder-gluer · TPG-257
Boxes opening in transit or filling (pop-opens)
Client reports open boxes; the bond looked fine in production
Folder-gluer · TPG-259
Skewed box or misaligned flaps (fishtailing)
Closed carton comes out rhomboid; flaps don't meet
Folder-gluer · TPG-261
Crash-lock bottom malformed
Bottom won't erect or its glue points fail
Folder-gluer · TPG-265
Stepped hotmelt temperature profile (optimal setup)
Inconsistent bead, stringing, short open time or degradation with a seemingly 'fine' setup
Folder-gluer · TPG-266
Char in the hotmelt tank
Black specks in the bead; nozzles clogging often; burnt smell; darkened adhesive
Folder-gluer · TPG-267
Clogged gun nozzle or intermittent bead
Bead breaking up, deflected or absent; boxes with missing glue
Folder-gluer · TPG-269
Uneven temperature across tank, hose and gun
Adhesive leaving cooler or degraded despite a correct tank setpoint
Folder-gluer · TPG-270
Hotmelt pump without pressure or fluctuating
Weak or speed-varying bead; missing glue at high speed
Folder-gluer · TPG-271
Gun firing out of sync with the box
Bead starting before or after the flap; glue on the edge or a bare flap end
Folder-gluer · TPG-258
Glue bead outside the flap (visible glue)
Glue peeking out of the finished box edge; boxes stuck together in the pile
Folder-gluer · TPG-260
Insufficient pre-fold (pre-breaking)
Boxes not flattening, bulging in the pile or levering the bond open
Folder-gluer · TPG-262
Scuffing of boxes by belts and guides
Shiny or friction streaks on the printed faces
Folder-gluer · TPG-263
Double feed or feeder jams
Two blanks entering together or machine jamming at the feed
Folder-gluer · TPG-264
White glue drying on the applicator or stringing
Crusted disc/nozzle; intermittent application; glue threads over the machine
Folder-gluer · TPG-268
Hotmelt angel hair all over the machine
Adhesive cobwebs between gun and boxes; threads stuck to belts and guides
Folder-gluer · TPG-272
Adhesive degradation from long tank residence
Bonding worsening through the day at constant settings; visibly different viscosity; darker color