EN
In sheet extrusion and converting, the roller surface quality directly determines product appearance. If an embossing or calender roller develops rust, pits, scratches, or contamination marks, you will see defects immediately on the sheet surface—often leading to customer complaints and wasted material.
This article explains how to maintain rollers on a sheet making machine (including sheet extrusion and downstream calendering/embossing units). It is especially useful if you operate equipment related to sheet extruder, sheet cutting machine price comparisons, or small plastic bag/sheet converting lines.
1. Why roller surface finish matters
Rollers control:
- sheet gloss and texture
- thickness uniformity
- traction and winding stability
- emboss pattern clarity (if patterned rollers are used)
A small defect on a roller becomes a continuous defect on the sheet—creating long scrap rolls.
2. Main causes of roller damage
- moisture and poor storage → rust
- improper cleaning chemicals → corrosion
- metal tools used on roller surface → scratches
- contaminated resin dust and additives → abrasive wear
- incorrect nip pressure → surface fatigue and pitting
3. Daily cleaning: the safest method
Recommended routine:
- stop machine and follow lockout procedures
- allow roller temperature to reach safe handling range
- wipe with approved non-abrasive cloth
- use compatible solvent (confirm with roller material/coating supplier)
- remove adhesive or resin build-up gradually—never with sharp tools
Avoid:
- steel blades on chrome surfaces
- aggressive acids/alkalis without confirmation
- high-pressure washing into bearings
4. Rust prevention and storage standards
If the machine stops for days/weeks:
- apply anti-rust oil or protective coating
- cover rollers with moisture barrier film
- keep workshop humidity controlled
- rotate rollers periodically to avoid contact spot corrosion
For spare rollers:
- store in dry racks
- protect journals and bearing seats
- keep documentation of surface finish specs
5. Periodic inspection: catching pitting before it becomes scrap
Inspection checklist:
- visual inspection under strong angled light
- feel test with clean gloves (no grit)
- measure runout if vibration or thickness variation appears
- check bearing temperature trends and lubrication condition
If pitting is found early, re-polishing may restore surface; if ignored, replacement cost and downtime increase sharply.
6. When defects appear on sheet: quick diagnosis map
- repeated line marks → roller scratch or embedded debris
- dull patches/gloss variation → contamination or chemical attack
- periodic patterns repeating every rotation → roller pitting or runout
- thickness banding → roller alignment or nip pressure imbalance