Coated board is a premium “paper” that requires high printability. Without precision roll grinding, high-quality sheets are rarely produced consistently over time. One of the most modern mills in the paper industry learned this empirically.Historically, this paper manufacturer had employed mill roll services from partners who did not use precision grinding practices. Problematic in its own right, this issue was magnified by the faster speeds at which the paper mill ran its machines.
The coated board machines were designed to run at speeds that produced 700 tons a day, but this paper manufacturer had a production budget of 925 tons per day and ran its machines at 200 feet per minute faster than the machine was designed for.
Any imperfections in their rolls were amplified by the significantly increased machine speeds.
What happened when the modern mill made the switch to a precision roll grinding company?
Precision Roll Grinding Made A Substantial Impact
This paper mill, having enlisted PRG to grind its rolls, experienced the tangible result of precision grinding on its production efficiency. With PRG, the mill was able to use its rolls for up to 12 months without needing any servicing – practically doubling its roll life.
The coated board manufacturer was able to cut some 36 hours of scheduled maintenance downtime, saving approximately $900,000 per year.
As for the specific properties of coated board production, the switch to PRG optimized the mill’s production by way of:
- Improved yield by approximately 1.0% to 1.5% – an estimated annual cost savings of $1.0 to $1.5 million
- Greater levelness (printing surface uniformity) – from 500 sheet-finish variability to 700, a 40% improvement
The paper mill also experienced several additional improvements related to its sheets and production, which collectively increased the manufacturer’s profitability.
What Was Behind The Great Improvement?
In coated board production, there are two primary means of caliper controls: the wet stack and the dry stack. The former is when moisture is used to enhance calendering results; the latter is when hard steel rolls press against the board in a calender configuration.
Because the paper mill was no longer running rolls that had barring, feedlines and surface variances, its calenders no longer needed to work as hard to produce the smoothness its clients demanded. It used fewer fibers, improved its yield and significantly reduced the cost of maintenance.
But, that’s not all.
Read the full case study to learn how else the coated board manufacturer benefited from precision grinding.