On a corrugated board line, inner paper blistering at the single facer usually points to the brake system, the air duct, or the cylinder. The fix depends on which one is unstable.
Main causes
Brake system: if the brake is loose or slipping, it cannot clamp the paper firmly. Bubbles form during pressing.
Air duct blockage: a blocked air duct causes uneven internal pressure. The paper blisters at high speed.
Cylinder problem: air leaks or uneven pressure make pressing pressure unstable. This causes blisters.
Single facer operating rules
Startup preparation:
Make sure valves are open and pressure reaches about 8.
Turn on power and the motor. Run the machine at slow speed.
Check the machine for abnormalities. Confirm the raw paper is suitable.
Set preheat roller temperature at 85 to 90°C.
Check glue tank depth at 0.5 to 1 mm.
Running notes:
Check inner paper tension. Keep it free of glue failure and blisters. Keep paper edges aligned. Adjust corrugating medium tension as needed. Check that the baffle is in place.
After threading paper on the bridge, prepare raw paper for the next order. Organize the corrugating medium roll. Clean the area.
If paper breaks, tell the double facer to slow down. After splicing, run the paper quickly onto the bridge. After the splice is good, tell the double facer to speed up.
Check board quality every 20 minutes, including pressure. Slow down immediately if a problem appears.
Faster board speed needs a smaller glue adjustment. This saves glue and reduces glue failure.
When running a new machine, feed paper from both sides to help run-in.
Blister causes include glue amount, preheating effect, and air line setting.
Problem handling
Collapsed flutes can come from glue or foreign matter on the glue roller, a brake that is too loose, air duct misalignment, or original paper bias blister.
Inner paper blisters can come from a loose or slipping brake or a blocked air duct.
When the board moves up and down the bridge, adjust the wrap angle or check paper pressure.
Reversed or broken flutes can come from a loose corrugating medium, too much or too little glue, or too much pressure roller pressure.
Align paper with the floor ruler during feeding. Fine adjustment is allowed.
Glue amount depends on paper dryness and grammage.
Glue failure can come from glue amount, insufficient pressure, or improper fine adjustment of the glue baffle.
At high speed, board temperature also affects inner paper blistering. Too low a temperature gives insufficient gelatinization. Too high gives over gelatinization. Adjust the corrugating roll and preheating cylinder temperature so the paper gelatinizes correctly. If needed, check steam pressure and steam temperature, and adjust the siphon position.
When brake pads, pressure rollers, or glue rollers need replacement, Hansheng Automation can machine these precision parts from customer drawings in single pieces or small batches.
Our precision parts custom machining is not limited to single facer components. We also produce non-standard parts for yacht hardware, RC car parts, printing equipment, medical devices, tobacco packaging machinery, filling machinery, and food machinery. Hansheng Automation supports single-piece and small-batch production from customer drawings. We focus on precision parts machining and delivery, which helps maintenance and replacement across different industries.
