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Some call him surface pope. Alfons Wimmer gave sawn timber an antique look as early as 25 years ago. Until now, he has only been able to achieve many effects with elaborate manual work. Since the beginning of the year, two new wide-belt sanders have been doing this work for him.
On the right and left of the visitor entrance to Alfons Wimmer's 25-man carpentry in Mühldorf, Upper Bavaria, untreated but brushed and sanded boards lean against the door frame. The entrance opens to the south, so that the boards not only receive rain, wind and storms, but also the sun. Alfons Wimmer picks up a board, holds it up against the light and caresses it lovingly. He is delighted with the natural complexion and the sandblasted structure of larch wood. Such surfaces are very well received by its customers. I follow him inside and find myself in the reception room. The furniture and decor reminds me more of an antique shop than a carpentry exhibition. On sideboards, tables, reception desks and window sills, as well as in Alfons Wimmer's office, there are a myriad of wood patterns, solid wood, veneered panels, homemade three-layer floor elements or frame-and-panel doors. The surfaces are sanded, delicately or very strongly textured, stained, patinated, waxed, oiled or painted. Some patterns have a precisely flat surface, others a slightly wavy surface, as if the boards were planed by hand. From rustic to dignified to high-gloss, there is something for every taste here.” In Asia, such effects are produced by hand,” explains Alfons Wimmer, “We can only do this economically with a machine. That is why we put two new wide-belt sanders into operation at the beginning of the year. ”
Alfons Wimmer cuts most veneers on his own log band saw. Normal measured veneer is steamed and no longer matches the color of solid wood. In addition, the sawn veneers, which are usually 3 mm thick, can be structured particularly deeply and even worked with a roughing plane. Scraped wood can be compared to a very shallow hilly landscape. Until now, employees have actually created this effect by hand with a rough planer and then smoothed out the surface with the orbital sander. They also created the rough saw effect with real saw cuts on the log band saw. The old wide-belt sander was unable to produce these effects, nor was it able to structure it as deeply and variously as Alfons Wimmer imagined. For two years, he worked intensively on the selection of a new broadband machine and then ordered two different ones from Heesemann.
He uses the smaller and simpler but stronger “MFA 10” with a calibrating roller and two brush rollers for the rough, i.e. calibrating boards and the self-cut veneer as well as heavy structuring tasks. For rough calibration work, the calibrating roller has a fixed cutting speed. The large structuring brush, on the other hand, can be adjusted continuously. For fine things, he has also ordered the “MFA Impression” model with water-cooled servomotors from Heesemann. These drives allow particularly low speeds, so that the machine can grind or polish not only wood, but also paint and plastics. Metals can also be processed.
Alfons Wimmer chose a cross sanding belt as the first unit. It is followed by a combination longitudinal sanding unit with link pressure shoe. The joinery uses it for contact sanding of solid wood, veneer and paint as well as for calibrating plastics at low speed. This is followed by two brushing units. The first is equipped with a stainless steel wire brush on the left side and a braid wire brush on the right side, the second with an andalon brush. As a rule, the second brush runs the other way around than the first so that it removes the loose wood fibers. On the machine side, employees choose whether they want to structure more strongly with the harder brush or only slightly with the softer brush. Other parameters include the speeds, the directions of rotation and the pressure resulting from the height of the unit.
The last unit is called RUT, which stands for Rotating Circulating Plate Brushes. It consists of 19 disc brushes, which move across the full grinding width of 1350 mm across the feed direction. The unit can be equipped with wire or grinding brush and grinds or structures the entire workpiece evenly in different directions so that, as with an orbital sander, no visible sanding marks remain. If the front and back of the grinding blades have different grits, the grain size can be selected by changing the direction of rotation without changing the tool.
For the roughing effect, the machine control system uses a random generator, which controls the link pressure bar and grinds some regions of the surface and not others. Between link pressure bar and sanding belt, there is a steel plate with segmented graphite coating specially for this process.
Alfons Wimmer achieves the sawdust effect with the transverse belt with extremely coarser grit at a minimum grinding speed.
Alfons Wimmer summarizes his experience with the machines: “A machine for rough work and a jack-of-all-trades for everything else — this concept really works for us. We have been working with the machines since the beginning of the year and have soon created 100 programs. All effects can be amplified or attenuated and combined with each other in any way you like. There are now no limits to my creativity and my urge to create new surfaces over and over again. Of course, we also save a lot of working time because we no longer have to create the effects manually. ”
Alfons Wimmer Interior Design GmbH
84456 Mühlendorf,
