ApplicationsMay 27, 2019

Sawmill achieves performance improvements with CC-Link IE

Operating a sawmill requires continuous improvement to the speed and productivity of the process.

DTE's wooden packaging plant includes over one hundred inverter drives, all of which need to be controlled simultaneously and in real-time. A new communications network able enabled it to connect its inverters to PLCs, and ensure that the machines could instantly adjust operating parameters for optimal performance.

When Dansk Træemballage A/S (DTE) looked at how to increase the precision and productivity of its sawmill, one of the major challenges was to establish the right automation control network. As the biggest producer of wooden packaging in Denmark, the plant includes over one hundred inverter drives, all of which needed to be controlled simultaneously and in real-time. The technology used to address this challenge was CC-Link IE, an open gigabit Ethernet protocol designed for industrial automation tasks.

DTE’s sawmill is located in Ribe, Denmark and dates back to 1581. It is now the mainstay facility for the company’s pallet production activity. Every day, approximately 35 trucks bring conifer logs to the saw line to produce lumber, resulting in over 300,000 m3 of raw timber being processed every year. This is then exported or distributed across DTE’s five production sites to obtain 150,000 m3 of finished wood that is used to assemble crates and pallets.

The sawmill is comprised of a number of stations, which turn logs into rough-cut timber and eventually finished lumber by performing debarking, profile cutting, sawing, sorting and stacking activities. All these stages require high-quality, reliable and responsive inverter drives to correctly position and power processing equipment such as grinding rolls and saw blades.

“Running a sawmill means continuously improving the speed and productivity to get the most out of the raw materials. A quality finish is also particularly important for DTE, as we mainly focus on the food industry, which has strict standards on the end quality of the crates and pallets,” Orla Poulsen, owner of DTE, explained.

Inverter drives

Interconnected & responsive mill

To keep operations at the site in Ribe smooth and efficient, DTE needed a communication network technology able to connect the inverters to PLCs and ensure that the machines could instantly adjust their parameters for optimal performance. Thus, the company appointed Hans Folsgaard as its technical partner to upgrade the plant automation system.
Carsten Olesen, Technical Manager at Hans Folsgaard, agreed with Orla Poulsen: “Accuracy is fundamental. This is why DTE asked us to find a fast network technology.”

Effective high-speed transfer of data creates a highly responsive system, Lars Venborg, Technical Manager at DTE, commented: “In order to improve the quality of our lumber and increase our productivity, we wanted better precision and a faster reaction from the variable frequency drives across the processing line. The old network had become slow by comparison and could no longer support our manufacturing needs.”

The choice of which network solution to use was immediate for Hans Folsgaard. CC-Link IE technology provides data transfer rates of 1 Gbps for high-speed communications. Also, by offering a maximum of 254 stations per network, the solution could accommodate all the variable frequency drives across the saw line as well as supporting future growth.

Tim Lomax, Director of the CC-Link Partner Association-Americas (CLPA-A), explained that DTE is using CC-Link IE to build a very large network of inverters that operate this sawmill. The result is higher productivity and increased business competitiveness as quality and output both rise, without changing the mechanical aspects of the plant machinery.

“It is very important that DTE can get the maximum yield out of each log,” Lomax said. “The benefit that the high-speed response time and bandwidth that Gigabit Ethernet offers, is that the machines on the saw line can assess the dimensions of each log as it goes through the mill in real-time. In this way, DTE is able to very accurately measure each log and can make the most use of its raw materials.”

User-friendly, future-proof solution

By choosing CC-Link IE, DTE will also benefit from an easy-to-use system that simplifies management and maintenance in the future.

“It is very easy to work with CC-Link IE. When we chose this solution, we also considered maintenance activities and the future of the sawmill. It will be very easy to replace or add inverters, when required, as we will not have to change anything in the software setup,” commented Lars Venborg. “CC-Link IE offers a smooth setup that does not require any programming,” Olesen further explained.

Not every network offers such a flexible platform to build upon, continued Venborg: “This was not the case with our existing system. We had to modify the software every time we replaced an inverter. As a result, we used to struggle with downtime, and we always needed both technicians and programmers to replace or add a drive, affecting uptime and productivity.”

John Wozniak, P.E., Manager, CLPA-Americas