Since the two German companies Holtec and HFHN formed a strategic alliance a few short years ago, they have completed three joint projects in the wood preparation area of panel mills. One of their latest projects involved the supply of what the companies claim is the world’s largest flaker for OSB.
“With the installation of this new OSB flaker a new, important milestone in our short company history was set,” said Wolfgang Holzer, managing director and company founder of HFHN. “When we founded the company in 2001 we had the vision to develop and build large OSB flak- ers. We started with OSB stranders at the mill of one of the west European  pioneers of the OSB industry.”
The company says the new system, con- sisting of a feeding and loading system, as well as modified batch-feeder and flaker type WZU 250 with chip evacuation and sieving, will in future replace the existing type of flaker.
“In close coordination with the client, an individual plant concept was developed for the very confined space available at the site,” said Mr Holzer. The clear requirement  of the customer was for a capacity increase of 100% over the existing machine.”
Mr Holzer said there have not been any single machines on the market which could guarantee a capacity of 40 tonnes (absolutely dry) per hour.
“In addition to a new flaker generation, a new feeding and loading concept was also necessary,” he said. The challenge was accepted jointly by Holtec and HFHN, which last year realised their biggest project to date–a complete logyard for an MDF mill in Russia.
The new system was installed in parallel to the existing line and was started without significant interruption of that line.
The cross-cut logs are fed between the two systems via an adjustable tilting belt. A hydraulically-controlled step feeder transfers the logs in parallel and aligned to the log deck in front of the batch-feeder.
“Holtec delivered the first step feeder to the customer in 1998. The concept and the advantages were convincing,” said Alexander Gebele, managing director of Holtec. “That step feeder will be a core part of the new feeding, too, in order to guaran- tee a high availability of the system.”
A special challenge was the loading of the 2,000mm-wide channel of the batch feeder. In cooperation with HFHN, Holtec developed a solution with a moveable log deck. The companies say this guarantees that the conveyor, with a cross-section of nearly two square metres, is always filled. “This is the most important condition for a continuous achievement of capacity,” said Mr Gebele.
The knife carrier disk, a core part of the machine, was equipped with a special knife system, also developed by HFHN, and the company says the quality of the strands obtained has pleased the customer with a significantly low level of fines and big, plane flakes making for a top board quality.
The batch-feeder was made by HFHN in heavy duty form at the customer’s request. The feeding of the system was effected through a two-stage slider concept.
“This allows a continuous and uninter- rupted chipping,” reported Marcus Weber, sales manager of HFHN.
“The flaker itself convinced because of its basic data: inside diameter of knife-carrier disc 2,500mm, disk width 725mm and driving power of 1,000kW. The system was sup- plied as big units and its total gross weight was approximately  100 tonnes. The large weight invests the system with a capacity for very reliable operation,” said Mr Weber.
The knife carrier disk, the core part of the machine, was equipped with a special knife system, also a further development by HFHN. The customer was convinced of the benefit of this by the quality of the strands, claimed Mr Weber.
The second installation of the new flaker generation is now being made in a new OSB mill in eastern Europe, while Mr Weber said further promising projects are currently being worked on by the two companies.