Three years ago, the family-run companies Echtle, Streit, and Kübler founded the CLT manufacturing business Holzbauwerk Schwarzwald. Each of the three companies contributed their own expertise to the project. The joining know-how comes from sawmill and processing company Kübler, which has been active in beam joining for over 30 years and in timber frame construction for over 10 years.
The positive experiences which Kübler had had with Hundegger in the past were also decisive in this project: The machine manufacturer from Hawangen was awarded the contract for the delivery of two PBA-Industry panel processing machines. “The advantages of joining CLT with Hundegger machines are the same as 30 years ago with beam joining. Both the software and the machine control system simply work very well,” managing director Jörg Kübler explains.
During project planning, a conventional processing table was designed at first. “During the negotiations with Hundegger, though, it became clear that the machine can do a lot, but not everything. The clamping of the panels was a limiting factor, which we didn’t like. Then, the vacuum table, which was not yet available on the market at the time, came up during discussions. Eventually, we put the prototype of that table into operation,” Kübler tells us. Today, the company, which is based in the Black Forest, uses two PBA-Industry panel processing machines.
Designed for a continuous workflow
“The machine’s design makes it possible to have pieces pass through continuously and it consists of three parts. Behind the infeed, a roller conveyor transports the CLT elements to the vacuum table in the machine and once they have been processed, the elements are transferred to the storage table,” Andreas Bauer, head of joinery and construction at Holzbauwerk Schwarzwald, explains.
This way, the next panel can already be placed while the previous one is being processed, thereby ensuring the highest possible machine utilization. After the panel has been positioned on the vacuum table, an optical measurement is done, which automatically determines the position of the panel on the vacuum table and adjusts all processing steps accordingly. During positioning, care is taken to make sure that there are enough vacuum cylinders under each element to securely fix the panel. Collision monitoring ensures that the vacuum cylinders remain undamaged during processing.
No project is too complex
In addition to the 60-kW spindle, the vacuum table is without doubt the heart of the machine. In total, the table has 250 individually controllable vacuum cylinders. “This technology has worked perfectly from the start, and we have never had a damaged cylinder,” Bauer emphasizes. A mobile tool changer equipped with 20 tools ensures short set-up times between processing steps.
A major advantage of the table is its ability to lower individual parts of the panel after they have been cut, which makes it possible to machine the narrow edges within one nesting. “We have some customers who come to us because we can do high-quality joining for very complex projects, too. Ultimately, these quality standards are the key to success in modern timber construction,” Kübler says.
Maximum feed speed
Thanks to the vacuum clamping, even small components can be processed at maximum feed speed. “Especially thin panels or smaller components whose panel weight would normally not be large enough now hold securely. This has enabled us to significantly increase our manufacturing accuracy,” Kübler says with satisfaction.
For the joining of CLT elements with a silver fir surface, the processing of which is considered to be challenging, Holzbauwerk Schwarzwald worked closely with Hundegger’s tool development department and developed solutions for high-quality element joining.
The vacuum tables make it possible to process CLT elements from all sides and to carry out even very complex projects. Small components, too, are fixed precisely, which has significantly increased manufacturing accuracy and enables us to always produce at maximum feed speed.
Perfect combination
Both von Kübler and Bauer particularly praise the flawless combination of vacuum table, processing unit, tools and software, and add that the Hundegger team always implemented the company’s wishes and suggestions within a manageable time frame.
“In terms of the software, our goal was to achieve maximum automation while minimizing the need for manual intervention. This involves a different nesting process,” Kübler tells us. While cuttings which can be conveyed are removed together with the processed elements, the PBA-Industry completely machines any cuttings which are too small.
In order to be able to fully exploit the potential of the powerful 60-kW spindle, which reaches up to 12,000 rpm, a good combination of tools and spindle is essential. Here, too, Bauer and Kübler praise the close and fruitful collaboration with Hundegger’s tool development department which enables the company to always use optimally designed tools.
Small but important details
“The machines have many great features. The tables have a system with brushes which automatically adjust to the thickness of the panels and clean them. When there are cuts, nozzles also blow out the dust which is then removed by the extraction system. This way, the panels are clean when they are placed on the storage table,” Bauer explains.
The vacuum cylinders clean themselves when the elements exit the machine on the conveyor. In order to reduce the amount of dust in the hall to a minimum, Holzbauwerk Schwarzwald installed a curtain made of plastic strips in front of the exit conveyor. “We were able to implement this solution quickly and pragmatically with Hundegger,” Bauer adds with satisfaction.
