Schnaithmann Maschinenbau GmbH manufactures conveyor and assembly systems for automation, assembly, material flow and handling tasks in Remshalden near Stuttgart. Schnaithmann has developed a conveyor system for a new baking oven line for the traditional Swiss company V-Zug AG, manufacturer of high-quality household appliances. At the production site in Zug, Switzerland, it ensures the smooth transport of different types of appliances through the individual assembly and testing stations. The modular conveyor system can be flexibly adapted to the respective production requirements and can also be expanded so that all current and future oven types can be assembled there - even in batch size 1. The new conveyor system also increased the degree of automation within the oven assembly.
For more than 100 years, high-quality and innovative household appliances have been manufactured in the Swiss community of Zug. In 1913, the company's history began with a galvanizing plant, where sheet metal goods for household and handicraft were produced. Soon afterwards, V-Zug also began producing hand-operated washing machines, which were followed by fully automatic washing machines, tumble dryers and dishwashers from the 1950s onwards. Today the product range also includes ovens and stoves, steam cookers, hobs, microwaves, coffee machines, extractor hoods as well as refrigerators and freezers. V-Zug's appliances rank in the high-priced premium or luxury segment. The company generates an average of 80 to 85 percent of its annual sales, currently around 600 million Swiss francs, in Switzerland, with the remainder being generated primarily in France, Belgium, China and North America.
The complete range of equipment is manufactured to order, except for a few models, which means that production varies greatly. Each household appliance should be shipped within two days of receipt of the order. For a goal like this, in-house production depth is important. A new pressing facility is currently being built at the Zug site with ultra-modern servo transfer presses, on which all sheet metal parts for the household appliance range are to be manufactured. "We are making this effort quite deliberately," explains Roman Janser, head of assembly in the Kitchen segment, "because we want to be as independent as possible from suppliers. We are also the only domestic household appliance manufacturer that develops and manufactures its products exclusively in Switzerland. For us, 'Swiss Made' is therefore not only a seal of quality but also a promise of value.
Every household appliance from V-Zug must pass through up to a 600 test processes during its production without errors before it is released for shipment. This and the high proportion of manual assembly work are time-consuming. For this reason, V-Zug attaches great importance to manufacturing and logistics concepts that guarantee the highest possible productivity without overburdening employees. Such concepts are developed in-house in the plant planning department. Project manager Paul Cathomas explains: "We work very closely with our development department and therefore know the technical specifications and features of each new device very early on. Furthermore, we know better than any external planner the sequence of the individual production and testing steps, their subtleties and the respective time requirements. We know the premises in which the system is to be installed. And we are always present, so we can quickly adapt our system planning or optimize assembly and logistics processes if necessary in the event of design changes to the product". When planning all parts of the system on which a household appliance is to be manufactured, tested and packaged, Cathomas and his staff draw on extensive know-how, e.g. with regard to the targeted use of automation and robot technology for monotonous or difficult work steps, the ergonomic design of workplaces, or intralogistics and kanban control. The experience of the employees from production and assembly is also brought into this planning process. In addition, the specifications of the required manufacturing and assembly equipment are defined and who is to supply it. The construction, installation and commissioning of the system in accordance with the detailed specifications of V-Zug is then usually the task of a system designer as general contractor. The assembly and testing equipment are expected to have a high level of availability, reliability and durability. Several generations of equipment are manufactured on each system over the course of its life, so that only product-specific adaptations are required in the event of a product relaunch.
Two years ago, V-Zug needed a new system because the old one had technically outlived its usefulness. The development department worked on a completely new oven line based on a modular platform for several different types of appliances. The engineers worked on production and logistics concepts in the system planning. The question arose as to the most suitable conveyor system on which the new ovens would be mounted and tested, similar to workpiece carriers. "In line with our platform concept, we needed a modular conveyor system that could be adapted or extended to our respective production requirements so flexibly that we could mount all current and future oven types on it - even in batch size one," recalls Roman Janser. Janser, Cathomas and colleagues made themselves familiar with the system at Motek 2017 in Stuttgart, where they met Schnaithmann. In the same month, V-Zug sent Schnaithmann a concrete inquiry for a conveyor system. Sales engineers from the Remshalden-based machine manufacturer traveled to Switzerland to discuss the specifications of the desired system and the scheduling together with V-Zug. They had agreed on an accumulating chain conveyor system that not only met the required technical specifications with regard to load capacity, height, indexing and control, but also offered the desired modularity, scalability and reusability. In January 2018, the supply contract was signed and sealed. Because the new oven types were to be launched on the market as quickly as possible, a two-stage plan was defined: Stage one comprised the delivery, installation and commissioning of the conveyor system in the test area by June 2018, while in stage two the same was to be done by the end of the year in the assembly area.
One challenge was a special spatial issue in the Swiss plant: the test area is located in a mezzanine above the assembly area. The ovens had to be raised to this level. There was a lift, but it was not compatible with the desired conveyor system. A new lift was therefore required. Schnaithmann had already installed similar lifts in the assembly department of an automobile manufacturer. "The way in which this task was solved shows Schnaithmann's great experience in special machine construction," emphasizes Cathomas. "In general, the cooperation was very close and good right from the planning phase". Wolfgang Schneider, Key Account Manager at Schnaithmann, agrees with this. All coordination was carried out through the short official channels. The same is true for the company itself. Sales engineers and designers, who form a project team, sit table to table. This always means that all those involved have the same level of knowledge about the progress of the respective project. And for each customer there is only one contact person, the project manager. "For us, it was not so much the required technical specifications that posed the greatest challenge, but the tight schedule," explains Schneider. "We also manufacture standardized components in stock to keep delivery times short. These are normally between eight and twelve weeks, but with a system of this kind, you need a lot more time. The weight and size of the furnaces were no problem for our conveyor systems, but we had to install and commission one part of the system within a two-week time frame while production was still running, and the other part during the company vacations between Christmas and New Year's Day".
The implementation on site was then mainly the task of the team from Cathomas and Janser. The installation manager remembers about 40 moves before, during and after the installation of the conveyor system. Parts of the assembly line including the automatic stations were dismantled and rebuilt on a cleared area in order to be able to continue production for a few days and to make room for the new conveyor system. "The service technicians and programmers from Schnaithmann managed the installation and commissioning professionally", praises Cathomas. "Even the one or other interface problem that did occur during the integration despite the exact planning was solved in an unspectacular way". It is important to mention this: With the new conveyor system, V-Zug has also increased the degree of automation within the oven assembly. "It doesn't help at all," explains Janser, "to install a future-oriented conveyor system and to leave the production technology at a level that no longer meets current and future requirements. Where manual work used to be the norm, multi-spindle automatic screwdriving machines are now in operation. Also the application of the heat insulation is no longer done manually but automatically. And there are more examples. The conveyor system has been in operation for a good year and Janser's conclusion is positive: "We have not had any problems so far. The availability of the system is very high. We are still not using it to full capacity in terms of cycle time. But that will come with the following oven types".