2011/06/11   |   Switzerland

Quality in focus in timber constrution

When it came to acquiring a new production line, Blumer-Lehmann AG was primarily interested in improving their quality management process. It was almost incidental that the new production hall became a flagship that the company could use to impress custom

In Switzerland, the positive trend in timber construction has led, amongst other things, to many timber construction companies expanding at a rapid pace. This has resulted in a large number of high-performing companies competing for an order volume that varies greatly from region to region and that is not unlimited. One of the companies competing for this volume is Blumer-Lehmann AG based in Gossau. By developing new products, the company is continuously tapping into new sales markets and thus improving its position on the market.

New products for all areas of the company

The innovative new products brought to market include, in equal measure, user-friendly modular construction concepts as well as new, highly complex facade structures, innovative construction technologies in the free-form field, and non-metallic timber connections for multi-story construction, such as the beechwood-reinforced supports and beechwood bolts used in a seven-story Tamedia office building in Zürich. With projects such as the Tamedia building or the extension to the Säntispark Hotel — the first four-story timber construction hotel building in the Canton of St. Gallen — the company has drawn international attention in recent years.

Blumer-Lehmann AG is divided into the areas of general contracting, timber construction, modular construction, and free-form constructions. In this last area, the company designs, produces, delivers and assembles free-form timber support and shell structures around the world. The supporting structures and facades, which are developed on a case-by-case basis, are produced on the company's own CNC machines in Gossau, requiring a great deal of skill in terms of the work preparation.

As a general contractor, Blumer-Lehmann plans and constructs turnkey buildings in timber or hybrid construction. In this market segment, which is seeing high levels of demand, the construction size ranges from a detached family house to a complex apartment building and large projects in the commercial or public sector, with a focus on multi-story construction.

In the field of modular construction, the company primarily creates timber buildings that are used on a temporary basis. The buildings can be delivered at short notice in various stages of construction or ready to use, and can be dismantled after a service life of several years. The buildings can then be erected again at a different location — a concept that is frequently used in urban areas for the temporary construction of schools based on need and urgently required hotels or homes for the elderly.

In the field of timber construction, Blumer-Lehmann AG meets a wide range of demands for timber buildings. The company constructs detached and semi-detached houses, agricultural buildings, as well as support structures, apartments, staircases and interior fittings. This particular division of the company also produces all timber components for the general contracting and modular construction projects.

Five assembly tables with a multi-function bridge

Regardless of whether the job is facade elements for hybrid construction or wall, ceiling and floor elements for the company's timber building — the focus of the element production is always on timber frame construction, which naturally also determines the structure of the production systems: At Blumer-Lehmann, production takes place on working tables and, up until two years ago, was performed primarily manually and in a very confined space. In 2013, with the construction of a new production hall, the company adapted its size to the production volume that had increased in the previous years.

The new production hall was equipped with a WEINMANN production line, including five assembly tables and a multi-function bridge. The main reason for this acquisition was the desire for consistent quality at a high level: As a result of the increased demands from builders, the strong competition in Switzerland, and the professional target group — a large proportion of orders come from architects — quality has become the essential basis from which Blumer-Lehmann works to achieve commercial success.

The first station in the new system is the manual timber frame production station. Inserted and nailed on the first table, the timber frame is transported on to table two, where handling systems are used to apply the planking. The WEINMANN multi-function bridge then nails the frame, cuts it, and creates the required openings.

Splitting the two process steps over two tables means that the system cycle time can be reduced: Further processing can take place on table two while the next frame is already being inserted on table one — one of the time-consuming process steps in the production line. If required, the beams for ceiling and floor elements can be inserted at table two, which is equipped with special fixing devices.

From table two, the element — which now has planking on one side — is passed on to table three via a turning operation; at table three, the insulation and installation materials can be inserted. As this is also a time-consuming process step, it can also be performed on table four in parallel. Transported across to table five, the element is then planked and processed by the multi-function bridge.

On to loading and module production

Some of the planking is prefabricated in a panel processing machine and then transported on to either interim storage or element production. The decision about which route the panel material takes is made on a project-by-project basis.

Manager Richard Jussel: "In continuous optimization steps, we are developing the expertise to know what to process best and where." For example, that can involve an acoustic panel with numerous holes and a complex cut, or, at times when the workload is high, prefabrication to avoid bottlenecks at the table. "This decision requires an intensive assessment of the project and the processes required for it."

Another special feature of the system in Gossau is the further distribution of the elements over two downstream lines: positioned by table five, the elements are transported to a distribution trolley via a vertical wall track. From there, they are either loaded onto pallets by the overhead crane or forwarded on to a further wall track. This wall track leads into the nave of the production hall with the module production system, where the elements can be removed and further processed at multiple assembly points.

Greater quality plus cost-reducing potential

Looking back, in Richard Jussel's view, the aim of achieving greater precision and thus a consistently high level of quality with the system has been achieved.

The correlations that exist between through put times and production costs are more complex for the manager: "Achieving a consistent production process at a high level of quality with fewer people was easy. However, to calculate times and costs precisely, we have to consider the additional outlay associated with the system, and those include, for example, more comprehensive work preparation."

In Jussel's view, there is therefore a need for standardization to make the system more efficient. "If you standardize individual elements and modules, you open up new potential for lowering costs."

The processes on and around the tables also have to be optimized to make the new system more efficient compared with the previous manual form of production: "That applies to the material flows in production, for example. Previously, in some cases, we had to carry panels and insulation long distances to the corresponding table, whereas today, everything is in the right place on the line, meaning that our employees only have to move short distances. It is precisely here that we can become faster and save costs."

The new acquisition has also fulfilled the company management team's wish for a clearly structured production process with better framework conditions for effective quality management. "One of the advantages of the WEINMANN production line is clearly visible production processes at clearly defined stations. Everyone knows where a process step begins and ends, everyone knows the material flows, and the project manager can tailor checks and communication accordingly."

The well-organized production hall thus brings the company a further benefit. "We can show this produc-tion facility to our customers to impress them and win them over for our company" — and the customers here are not only private customers, but also the architects who see industrial production at a high level of precision as a guarantee for low complaint rates. For Richard Jussel, who "still has a lot of public relations work to do to impress customers enough to make them opt for timber construction," this is a marketing advantage that should not be underestimated.

Source:mikado Unternehmensmagazin für Holzbau und Ausbau, Dr. Joachim Mohr, Tübingen


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