Sheets Unlimited, a major independent corrugated box manufacturer in the Pacific Northwest, has selected a Valmet IQ Quality Control System for corrugator for its operation in Renton, Washington.

The investment is intended to address one of the persistent quality challenges in corrugated board production: moisture imbalance and the resulting board warp.

Valmet said the system will help Sheets Unlimited improve board consistency, production efficiency and downstream converting performance.

Delivery is scheduled for the fourth quarter of 2026, with commissioning planned for January 2027.

Moisture Imbalance Targeted as Root Cause of Warp

Warp can create significant problems for corrugated board manufacturers because uneven sheets can affect subsequent converting processes.

For an independent sheet feeder such as Sheets Unlimited, controlling this issue can be particularly challenging.

The company sources roll stock from multiple paper mills, meaning incoming materials can differ in paper grade, moisture content and fibre characteristics.

According to Valmet, these variations can produce unpredictable warp behaviour that conventional corrugator controls may not fully compensate for.

The consequences can extend beyond the corrugator itself, affecting downstream converting performance, material consumption and finished board quality.

Krist Leland, Director of Manufacturing at Sheets Unlimited, said the company had previously observed Valmet’s warp-control technology operating at another European manufacturer.

“What stands out is its ability to address the root cause of warp: moisture imbalance.”

Leland said the investment should help reduce process variability and improve converting performance and product quality.

Valmet IQ Measures Moisture, Temperature and Warp

The delivery will combine several measurements and control functions within the corrugator process.

The system will cover paper temperature, moisture balance, total moisture and warp control.

It will also interface with the corrugator’s existing heating elements and incorporate Valmet’s moisture measurement technologies and automatic moisturizing solution.

Rather than responding only to warped board after it has already developed, the system is intended to provide data and automated control around the moisture conditions associated with warp formation.

Automation Aims to Reduce Production Variability

David Maddux, Board Converting Automation Sales Manager, North America, Automation Solutions at Valmet, said the system is expected to provide greater process stability and more uniform product quality while reducing operator workload.

Precise moisture and warp measurements can also help operators identify changing process conditions as different paper grades and roll stocks move through production.

According to Valmet, combining these measurements with automated control can help reduce material waste and improve resource efficiency.

For sheet feeders handling paper from several suppliers, this capability can be particularly relevant because the corrugator needs to accommodate variations in incoming material rather than operating around a single consistent paper specification.

Commissioning Planned for January 2027

The Valmet IQ system is scheduled to arrive at the Sheets Unlimited facility during the fourth quarter of 2026, followed by commissioning in January 2027.

The project highlights the increasing role of measurement and closed-loop automation in corrugated board manufacturing.

For Sheets Unlimited, the immediate objective is specific: improve control over moisture imbalance to produce flatter, more consistent corrugated board and support better performance in subsequent converting operations.

Last Updated on 14/08/2026 by Jota Machinery