Reference Projects

Published: June 24, 2026

Scope of delivery: Green sorting lines, sticker stackers, ROSY
Year of delivery: 2022

When Metsä Fibre built an entirely new sawmill in Rauma, Renholmen was commissioned to supply two complete green sorting lines. The delivery included two 300-metre-long green sorting lines, each with its own sticker stacker, as well as a closed-loop system for both kiln carts and drying stickers.

As part of the project, Renholmen also developed ROSY, a system that made it possible to automate tasks that previously required operators to be stationed out in the production area. Instead, the operators could work from a central control room and monitor the entire process from there.

Automation with ROSY

Buffers are installed downstream of the saw on both lines. If a sorting line stops, the timber is diverted to a buffer, allowing production in the saw to continue. Once the sorting line is running again, the buffer is emptied in parallel with the regular timber flow, with timber coming directly from the saw given priority.

Before the piece-by-piece feeding system, a camera system scans the timber flow and identifies deviations, such as defective or incorrectly positioned pieces that could cause problems further along the process. The information is sent to a robot that can automatically remove or reposition the affected piece.

With this solution, four operator positions previously required in the green sorting and sticker stacking areas have been replaced by robotic functions. At the same time, the operators’ role has shifted from manual tasks out in the production area to monitoring the process from a control room.

From green sorting to finished packages

Camera systems assess each piece of timber and determine how it should be cross-cut. The timber is then sorted into bins according to defined criteria. The bins are emptied and the timber is transported to the sticker stackers, where double-length packages are built with drying stickers between each layer.

The drying stickers and kiln carts are also handled in a closed-loop system. Drying stickers returning from the grading mill are transported to a separate section, where a Stick Inspector identifies and removes defective stickers. The approved stickers are then temporarily stored in a large buffer before being returned to the sticker stackers.

The timber packages are stacked on carts, which are transported through the kilns and then on to the grading mill. Once the timber has been unloaded, the empty carts return to the same section where the drying stickers are buffered. From there, they are returned to the sticker stackers and the cycle begins again.

An extensive project under exceptional conditions

The Rauma project was carried out during the pandemic, placing additional demands on planning and execution. Despite these conditions, the extensive delivery was completed according to plan.

The result was two complete green sorting lines with a high degree of automation, closed-loop systems for kiln carts and drying stickers, and the ROSY system, which transformed the way operators work within the facility.