A corrugator turns reels of paper into corrugated board using steam heat, starch glue and pressure. The corrugating rolls, pressure roll and preheaters are heated with steam, and their bearings sit right next to that heat. A grease that is fine on a fan motor can dry out, harden or run out of a corrugating roll bearing within days. Most corrugator bearing failures come down to three things: the wrong grease for the temperature, the wrong regreasing interval, and contamination from starch and paper dust.
Measure the real bearing temperature at each hot position and choose a grease whose continuous rating sits comfortably above it: polyurea or lithium complex up to about 160 °C, calcium sulfonate complex up to 180 °C (peaks to 220 °C), and PFPE up to 260 °C. Shorten regreasing intervals as temperature rises, give small, regular shots instead of large ones, never mix grease types, and follow the corrugator maker's specification wherever it names a lubricant.
| Section | Hot or critical parts | Typical lubrication | Watch point |
|---|---|---|---|
| Single facer | Corrugating rolls, pressure roll | High-temperature grease, or the maker's specified lubricant | Bearing temperature, grease drying out |
| Preheaters, pre-conditioners | Drum bearings | High-temperature grease | Hot bearings, steam leaks |
| Glue units | Applicator and doctor roll bearings, drives | Grease, gear oil | Starch contamination |
| Double backer | Hot plate area, belt drive rolls | High-temperature grease near hot plates | Heat, dust |
| Slitter-scorer, cut-off | Knife drives, gearboxes | Gear oil of the maker's grade | Precision, oil level |
| Stacker, conveyors | Chains, gearboxes, hydraulics | Chain lubricant, gear oil, hydraulic oil | Paper dust, chain wear |
The number that matters is the bearing's own operating temperature, not the steam temperature. Measure it with an infrared thermometer or a contact probe at each hot position, at full production, and write it down. Then choose a grease whose continuous rating sits above that figure with a margin.
| Grease | Continuous service | Best for |
|---|---|---|
| Lithium complex MP (NLGI 2) | −30 to +160 °C | Warm bearings on drives, glue units and conveyors |
| Polyurea long-life (NLGI 2) | Up to 160 °C | Higher-speed hot bearings, motors, long intervals |
| Calcium sulfonate complex (NLGI 2) | Up to 180 °C, peaks to 220 °C | Hot and wet positions: preheaters, roll bearings near steam |
| PFPE (PTFE-thickened) | Up to 260 °C | The hottest positions where other greases bake out |
The high-temperature grease guide compares these thickeners in more detail. Where the corrugator maker names a specific grease or a circulating oil for a roll, use that.
PFPE grease does not mix with ordinary greases. Before you switch a bearing to PFPE, clean out the old grease completely, then fill with PFPE only and use a separate, labelled grease gun. Mixed greases can soften, harden or lose their temperature performance; see can you mix two different greases?
Heat shortens grease life. A widely used bearing-maker rule of thumb halves the regreasing interval for every 15 °C the bearing runs above 70 °C. A bearing that needs grease every three months at 70 °C may need it every few weeks at 115 °C, unless you move to a grease built for that temperature.
Measure and record hot bearing temperatures at the single facer, preheaters and double backer. Check automatic lubricators are dispensing. Look for steam leaks next to bearings. Check gearbox levels and leaks, chain condition and hydraulic oil temperature. A rising temperature on one bearing is your early warning.
The same principles apply to printing presses, laminators and other converting machines. For the full range, see our page on packaging and printing lubricants.
Which grease is used for corrugating roll bearings?A grease whose continuous temperature rating sits comfortably above the measured bearing temperature: calcium sulfonate complex up to 180 °C, or PFPE up to 260 °C for the hottest positions, unless the corrugator maker specifies a particular lubricant.
How often should hot corrugator bearings be regreased?More often than cool bearings. A common rule of thumb halves the regreasing interval for every 15 °C above 70 °C, so measure the temperature and set the interval to match.
Can I top up PFPE grease with ordinary grease?No. PFPE does not mix with ordinary greases. Clean the bearing out fully before switching, and keep a separate grease gun for PFPE.
Why do corrugator bearings fail early?Usually a grease not rated for the temperature, intervals that are too long, too much grease in one shot, or starch and dust entering through dirty nipples and seals.
Running a corrugation or box-making plant? Send us your machine list and the bearing temperatures you measure, and our team will match greases and oils to each position.