The first batch of these 6-meter rollers was recently completed for a returning customer's wide-web coater, and this size has now been added to the regular product lineup. Below is a summary of the design approach and shop-floor test data.
Roller Body
Seamless steel tube with 20mm wall thickness is used for the roller body. On a 6-meter span, wall thickness is the primary factor controlling sag under dead weight. Insufficient wall thickness leads to deflection at mid-span, resulting in uneven nip pressure distribution across the web and consequent thickness variation in films or paper. At 20mm, the roller provides adequate stiffness for most industrial lines without excessive rotational mass that would overload bearings and drives.
Chrome Layer
Chrome plating thickness is specified at 12 microns. The practical consideration here is straightforward: thicker plating requires more grinding stock removal, and achieving a Ra 0.05–0.1μm mirror finish becomes progressively more difficult and costly. With 12 microns and a well-controlled hard chrome process followed by precision grinding, the roller consistently delivers a clean surface with minimal micro-defects. For coating, calendering, and pressing applications, 12 microns provides sufficient wear resistance. For operations that demand a thicker layer – 20 microns or above – the plating thickness can be adjusted accordingly, with corresponding adjustments to lead time and cost.
Runout and Balance
Total indicator reading (TIR) is held within 0.03mm, measured with bearings mounted and at simulated operating temperature. Dynamic balancing is performed to ISO 1940 G2.5, which covers the speed range of most paper and film lines operating at 600–1000 m/min. No vibration issues have been observed in field service at these speeds. Each roller ships with its own balance test report and runout measurement record.
Surface Finish
Measured Ra values fall between 0.05 and 0.1μm – a mirror-grade polish. This surface finish delivers two concrete benefits: it allows adhesive residues and coating materials to be cleaned off more efficiently, and it reduces surface defects on the finished web. Customers producing optical films and release liners have specifically identified this as a key advantage.
Typical Applications
This roller series is currently supplied for:
Casting, stretching, and winding sections on wide-web film lines (PP, PE, PET, BOPP)
Calenders, size presses, and coaters in paper machines
Precision coating equipment for optical films, release films, and lithium battery separators
Customization
All rollers are produced to customer drawings rather than held in stock. Journal types, flange connections, overall length, wall thickness, and surface treatments are all customizable. Prior to production, drawings are reviewed with the customer to confirm mounting dimensions, bearing fits, and clearance requirements.
