CLT machining without limits – quality and performance rise, costs fall

"Despite the fact that modern production facilities are becoming more and more powerful these days, the limiting elements are still the tools used" – Markus Derix, owner of the DERIX Group, knows what he is talking about. About two years ago, he implemented one of the most ambitious and largest projects in the European timber construction industry with the construction of an additional production hall for so-called glued laminated timber or CLT elements (Cross Laminated Timber). Here, wall and ceiling elements for prefabricated house construction are produced in absolute top quality with the help of the most modern production technology.

The new facilities are in operation. On a production area of about 15,000 square metres, about two hundred cubic metres of X-LAM, i.e. glulam elements for prefabricated construction, are produced here every day. Every day, up to five articulated lorries with finished building elements leave the premises of the internationally active specialist in Westerkappeln, which delivers its products all over the world. That's about 1,100 single-family houses per year. An impressive amount of material, considering that the entire value chain is run through here, from the raw material to the jointing, planing and pressing to the finished building element. The heart of the new production plant are the new CNC-controlled manufacturing units. Within a short time three hall-sized CNC machines produce house walls, ceiling elements or interior walls from the X-LAM raw panels weighing several tonnes. The system can produce building elements up to 40 square metres in size in just one clamping operation, with an extremely high degree of completion and perfect quality. "The demands of our customers with regard to dimensional accuracy and processing quality have increased more and more in recent years – and so has their cost awareness," Markus Derix explains. Almost every manufacturing company is familiar with the situation that discussions about prices and costs already begin in the planning phase of construction projects. "For us, this means delivering maximum quality while not losing sight of our manufacturing costs." This is understandable, because regardless of whether we are talking about multi-storey buildings or single-family homes, the final construction elements must be manufactured with absolute precision. After all, they should be able to be installed on the construction site precisely and without reworking. DERIX even goes so far as to prefabricate cut-outs for built-in elements such as windows, doors, fittings or even pipe and cable ducts with an exact fit and perfect finish. A lot of effort and, in view of the time and material planning of a production and the associated costs, a great challenge.

"Of course, we wanted to clearly benefit from the obvious advantages of CNC machining, but it was also important to reduce upstream and downstream work as much as possible. Our new CNC system is extremely powerful and we wanted to exploit that to the maximum," explains the owner and adds in conclusion: "It is not only important how many parts can be machined per day. The quality and the overall process have to be right."
A challenge for the company in any case. Because it turned out that the experience DERIX had made with commercially available tools in the initial equipment could not fulfil the high expectations. From the point of view of the project planners, it was clear that the decisive factor besides the machine is the tool.


"So we had to find a tooling partner who had particularly well-founded

know-how in terms of material, processing and machine technology

and could translate this into appropriate solutions that would take us forward.

We found this partner in Leitz."

Markus Derix, owner of the DERIX Group


As an example, he cites the corner trimming when cutting window or door cut-outs in wall components. "In the past, we had to cut the corners manually.  Of course, that took a lot of time, and the components had to be clamped several times until they were finished. With the help of the specially developed corner trimming cutters from Leitz, we can now carry out this work in just one clamping operation, save up to a third of the time in the entire process, achieve better quality than before and have far lower tool consumption than before," says Derix happily, giving details: "Today we cut our components at a feed rate of 25 m/min. That is twice as fast as before."

The fact that the overall process is so immensely important at DERIX can also be seen in the area of maintenance and reconditioning of tools used. "Currently, our order situation is excellent," explains the managing owner with satisfaction. "A correspondingly large amount of material has to be processed and our machines run in 2-shift operation five days a week." It is clear that a great number of tools must be permanently available so that production does not come to a standstill. "We cannot afford missing or non-functioning tooling technology, but here, too, we naturally pay attention to the costs," says Derix emphatically.  "That's why it was just as important for us to have a service partner who supports us here flexibly, quickly and unbureaucratically without exception." In cooperation with the Leitz service specialists, a tool store was therefore set up directly in the production hall. The responsible workers have short distances to cover when replacing tools and can carry out small service work themselves, such as replacing worn inserts or shrinking in new tools. The resharpening of complete tool systems, however, is still carried out by the nearby Leitz service station. "The service concept that prevails at Leitz is a stroke of luck for us," concludes Markus Derix.  "We receive reconditioned tools back in top quality, thus saving costs of new purchases and always have a competent contact person who can also be reached at short notice and supports us in word and deed. For us, this second side of the cooperation with Leitz perfectly complements our striving for more sustainability and resource protection in production."

The DERIX Group: The expert for constructive wood laminated construction
The DERIX Group is one of the leading manufacturers in structural timber engineering. It is established nationally and internationally and employs more than 240 people at two production sites in Germany (Niederkrüchten and Westerkappeln) and three further sales offices (Hamburg, Hermeskeil and Lierderholthuis) in the Netherlands. The focus of the owner-managed company is on the construction of complex hall supporting structures made of glulam and load-bearing structural elements made of X-LAM (cross laminated timber) for roofs, ceilings and walls. The main delivery area comprises Germany and Europe. As a manufacturer and supplier of laminated timber products, the company covers the entire range of glulam construction and sees itself as a partner for architects, timber construction companies and building contractors, with whom it develops and realizes national and international projects.

DERIX - focus on sustainability
The DERIX Group has set itself the goal of promoting timber construction and thus making popular a construction method that holds huge climate protection potential. If only it were used consistently, millions of tonnes of carbon dioxide could be bound in the long term, thus removing it from the atmosphere and effectively counteracting global warming. After all, one cubic metre of wood binds a whole tonne of CO2. And because DERIX uses wood from sustainable forestry, no forests are cut down as a result; in fact, more wood grows in Germany than is harvested. The DERIX Group increases this enormous ecological advantage that wood has over other building materials by placing particular emphasis on resource-efficient production processes, the use of renewable energies and the development of cradle-to-cradle concepts. The circular use of wooden components can extend the life cycle of buildings and materials almost endlessly and further store the bound CO2.


(Photos: DERIX Group)





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