Maintenance & Reliability · SOP
Edgebander Glue Spreading Roller Replacement
Safe, repeatable procedure for replacing the glue spreading roller and doctor blade assembly on HOMAG, SCM, and Biesse hot-melt edgebanders. Restores uniform glue application and prevents edge band delamination.
Estimated Time
60 min
Difficulty
Intermediate
Regulation
CSA Z432
Version
1.0
Purpose
To establish a safe, repeatable procedure for replacing the glue spreading roller and adjusting the doctor blade gap. This prevents glue line defects, reduces downtime, and extends the life of the glue applicator assembly.
Scope
This procedure applies to all industrial edgebanders equipped with a motorised glue roller and doctor blade assembly (common on HOMAG KAL series, SCM Pratika, Biesse Akron). Only qualified maintenance technicians with electrical/mechanical lockout training should perform this task.
Safety Precautions
- Lock and tag out main electrical disconnect. Verify zero energy with a voltage tester at motor terminals before beginning work.
- Wear nitrile gloves (glue contact), safety glasses, and heat-resistant gloves if the tank is still warm. Use adhesive solvent in a ventilated area.
- Glue roller and tank may retain residual heat up to 180°C. Allow a minimum 30-minute cool-down period after power-off before handling any part of the glue pot.
- Support the roller shaft when removing retaining bearings. The roller assembly weighs approximately 8 kg. Use a second technician for lifting if necessary.
- When using adhesive solvent (e.g., EVA cleaner), work in a well-ventilated area and avoid prolonged skin contact. Follow manufacturer’s SDS.
Required Tools & Materials
- New glue spreading roller (OEM matched to machine)
- Doctor blade (if worn or damaged)
- Set of hex keys (metric: 4, 5, 6, 8 mm)
- Torque wrench (10–25 Nm)
- Soft-faced mallet
- Brass drift punch
- 2-jaw puller (for sprocket removal)
- Temperature-resistant lubricant (e.g., Molykote 111)
- Adhesive solvent and clean rags
- Feeler gauge set
- Dial indicator with magnetic base
- Voltage tester
- Lockout/tagout kit
Procedure: Step-by-Step
1
Lockout/Tagout: Isolate power at the main disconnect. Lock and tag the switch. Test for zero voltage at the glue roller motor terminals using a voltage tester.
2
Remove Glue Pot Cover & Access Panels: Unscrew retaining bolts (typically M6 × 10 mm) and remove the front and side access panels that shield the roller and doctor blade assembly.
3
Release Doctor Blade Tension: Loosen the two locking screws on the doctor blade holder. Retract the holder approximately 5 mm away from the roller surface to relieve pressure.
4
Loosen Roller Drive Coupling: Remove the safety guard from the chain/belt drive (if equipped). Loosen the set screw on the drive coupling using a 4 mm hex key. Mark the orientation of the coupling halves for reinstallation.
5
Remove Retaining Bearing & Sprocket: Use a 2-jaw puller to remove the sprocket from the roller shaft. Unbolt the bearing housing (M8 socket) from the frame. Slide the bearing block outwards and remove the shaft retaining clip.
6
Extract Old Roller: With one hand supporting the roller, carefully slide it out through the access opening. Note the position and quantity of any shims or spacers on the shaft.
7
Inspect & Clean Mounting Area: Scrape off any dried glue residue from the bearing seats, shaft keyway, and frame. Wipe surfaces clean with adhesive solvent and a rag.
8
Install New Roller: Apply a thin film of temperature-resistant lubricant to the shaft where it contacts the bearing. Slide the new roller into position, aligning the key with the sprocket keyway. Reinstall the bearing, sprocket, and retaining hardware. Torque the bearing bolts to 20 Nm.
9
Set Doctor Blade Gap: Fit the doctor blade into its holder. Using a feeler gauge, set the gap between the blade tip and the roller surface to 0.05–0.15 mm (refer to glue manufacturer spec). Tighten the locking screws to 8 Nm.
10
Reinstall Guards, Power On & Test: Reinstall all access panels and safety guards. Remove the lock/tag. Restore power. Jog the motor momentarily to confirm correct rotation direction and that the roller turns freely. Run a production scrap piece to verify glue line uniformity.