More and more consumers want personalized products that are precisely tailored to their needs - from custom-made bicycles and self-mixed muesli to individually printed cola bottles and unique suitcases. The trend does not stop at the home either. Kitchen equipment should also be as individual as possible. It is precisely this trend towards individualization that French kitchen manufacturer Schmidt is responding to, perfectly complementing its existing batch size 1 concept with an innovative robot processing cell for drilling and fitting kitchen furniture parts. The cell is part of a production line with which complete kitchen fittings are manufactured in batch size 1.

Robot cell

The robot processing cell is located in Sélestat, Alsace. Sélestat is currently home to two production facilities of the internationally active kitchen furniture manufacturer Schmidt. Since 1934 (founded in Türkismühle, Saarland) and with over 1,500 employees, the name Schmidt has stood for particularly modern production technology and perfect quality. German perfection and French design guarantee affordable furniture for the highest demands. The robot processing cell is manufactured by the Zimmer Group from Rheinau in Baden. On the way to Industry 4.0, the Zimmer Group has developed from a classic component supplier to a system supplier and has thus produced an entire robot cell.

At the heart of the system are five fully-fledged ABB robots in a row, which are connected by a flexible transport system in which the workpieces are clamped and moved by up to four freely programmable shuttles, depending on their size. Incidentally, this circulating shuttle system won a German Innovation Award in 2019.

The robots provide furniture parts with holes, grooves and fittings in a tight cycle with workpiece intervals of less than two seconds. A two-metre high side panel of a tall cupboard can be immediately followed by the shelf of a shelving unit measuring just 15 x 20 centimetres. Without set-up time.

High-precision furniture parts

"When we first discussed our plans for such a cell, we were quickly told: don't do it, it can't be done with sufficient precision using robots," recalls Managing Director Achim Gauß, who is responsible for technology and sales at the Zimmer Group. "And that was the case at first. We had to invest a lot in hardware and software," continues Gauß. The special feature of this robot solution, for which the Zimmer Group also draws on its own pool of grippers and tool changers, is the drilling process, which is carried out by ABB industrial robots and can process the furniture parts with an accuracy of two tenths of a millimeter in batch size 1 on the robot. A self-developed compensation algorithm based on a laser tracker measurement of the robots in the machining area was used for this. The accuracy hurdle was also one of the sticking points in the entire process: the individual furniture parts are clamped into the shuttles by a loading robot and then their dimensions and position are measured. The parts are then guided along the various processing stations in a single set-up and finally removed from the shuttles by the unloading robot. This ensures that there is no loss of accuracy due to reclamping.

"Our customer Schmidt wanted a system that had 100 percent availability wherever possible, i.e. whose maintenance did not have to lead to complete machine downtime. This is only possible with a modular system. There was also the desire for flexibility, accuracy, expandability and a quantity 1 production without predefined machining programs," explains Gauß. The Zimmer Group experts solved the availability problem by ensuring perfect accessibility to all parts. For example, when changing the drill head on conventional machines, the casing first has to be laboriously removed. Individual shuttles can also be removed or replaced without bringing the system to a complete standstill. In extreme cases, it is also possible to "simply" replace an entire processing robot.

Two processing robots

In order to achieve the desired production output, the machining operations are automatically divided between two processing robots and typical machining operations - such as hinges and row drilling - are combined in one drilling stroke. For this purpose, the two machining robots each carry a multifunctional head with 41 tools, so that all necessary machining operations can be carried out without changing tools.