The packaging industry is always looking for new solutions to improve efficiency and quality in PET film production. With the launch of the roll stack XL, SML has set a new benchmark for the industry. By combining innovative technologies and an unprecedented width, a PET sheet line featuring the roll stack XL achieves output levels unmatched in the market. 

SML sets new standards in width 
Designed for a net film width of up to 2,700mm, the roll stack XL allows a throughput of up to 5,000 kg of PET per hour. “With the roll stack XL, our customers can efficiently produce high-quality PET sheets with thicknesses of up to 1,200 μm in large quantities”, explains Alexander Streicher, R&D Engineer at SML. 

Modular and divisible roll stack 
Thanks to our patented system, the roll stack (C0/C1/C2) can be divided into a base unit with C0 and C1, and a C2 unit. This is an innovative solution that increases the accessibility of the calender, facilitating careful cleaning and preparation of the roller before start- up –- an important step to ensure the quality of the production. "The divisible calender is a significant advantage for our customers," Alexander Streicher continues. "“It simplifies line-start-up enormously, reduces maintenance times, and increases the productivity and efficiency of the line.”  

Fully automated for enhanced comfort and safety  
A significant advantage of automation is its simple and comfortable operation. The C2 unit can be separated from the base unit and then re-docked in a fully automated process. The calender can also approach different working positions automatically to facilitate work and reduce downtime. 

Uniform sheet thickness using hydraulic roller and ax-crossing  
Achieving a consistent sheet thickness and perfect sheet quality across the entire width of the roll stack is particularly challenging for a line of this size. To overcome this, we have combined two systems to counteract the roller deflection and guarantee a uniform calendering gap. By adjusting the pressure in the hydraulic roller, the crowning of the calendering roller C0 can be changed steplessly, allowing for adaptation to the deflection. With ax-crossing, the tilt of the axis can be set precisely so that the size of the calendering gap remains the same across the entire width. This combination offers the highest level of production freedom and flexibility. 

“The roll stack XL is a prime example of our ability to develop and implement innovative solutions,” summarises Streicher. 

Redlham, 03.09.2025