Duroblade®-Energy™: a fast, effective way to solve LWC quality problems
In the highly competitive Light Weight Coated segment, BTG’s new-generation Duroblade-Energy ceramic-tipped blades are the ideal solution to many of the problems associated with traditional steel blade technology.
A well-known central European paper mill recently contacted BTG in a bid to optimize its LWC (light weight coated) operation. The mill, which had been using standard steel blades, was achieving average blade lifetimes of around 8 hours. Blades had to be changed at every web break, and dry bleeding was an additional problem. Short-term scratches were visible after the coaters, but not in the finished paper, and gloss levels were at the lower end of the quality scale for several grades.
BTG coating experts took an in-depth look at the mill’s process, and examined one of the worn blades. As a result, they proposed replacing the mill’s standard steel blades with Duroblade-Energy long-life high-performance blades, with equivalent blade geometry.
Figure 1:
Duroblade-Energy
Duroblade-Energy proved an instant hit, with the very first trial delivering a number of significant benefits. Very good and stable profiles were achieved immediately after start-up. And thanks to better coatweight leveling, the desired coatweight was achieved with reduced load, which allowed for the possibility of running 1.5% higher solids – delivering clear advantages in paper gloss, PPS and coverage. On top of that, the hood temperature could be reduced by 20%, for important energy savings.
The mill found that its new Duroblade-Energy blades could be used seven times longer than the old steel blades, surviving several paper breaks. Increased blade lifetime reduced the number of blade changes and ensuing broke.
Designed to meet the unique challenges faced by LWC manufacturers, Duroblade-Energy high-performance blades are available for all popular specifications, and tailor-made to each customer’s exact requirements for thickness, angle, length and width.
These first very promising results have been confirmed in a long-term ongoing trial. On top of the increased solids content and quality improvements, tests have been conducted to optimize the coating color formula. The mill reduced the clay component and chose a coarser – and hence less costly – pigment to compensate for the higher gloss achieved. The upshot: lower costs but sustained product quality, thanks to better blade work.
New challenge
These excellent results opened the door to trialing Duroblade-Energy in another of the company’s mills, where streaks and short-term scratches were leading to customer complaints. A reoccurring wrinkle in the middle of the paper trim was creating additional problems, and the mill found that at higher solids its steel blade would start to vibrate irregularly, creating ‘barring’ on the paper surface. The mill was changing its standard steel blades every 8-10 hours.
After thorough analysis of the coating process and the state of a used blade, the BTG team recommended switching to Duroblade-Energy. The results of the first trial have been extremely promising:
- Three times longer blade life
- No streaks
- Elimination of wrinkle problems
- Improvements in coating color distribution and printability
- Very short run-in time (good profiles after just 10-15 minutes)
The most important challenge – streak frequency and intensity – was entirely solved by the move to Duroblade-Energy. And while the problem of ‘barring’ remains unresolved, BTG’s experts are confident that a little more work on blade geometry and thickness will quickly solve this problem, too.
Today, the mill’s first orders for Duroblade-Energy have already been delivered – testifying to yet another satisfied customer who’s benefiting from BTG’s world-leading know-how, products and customer service.