The status-quo: Sinking numbers of pieces, increasing versions
The challenge: Cost reduction
In the past few years, model versions on the automotive market have continually increased.For the supplier, this means that production is shifting from the production of a lot of similar parts to fewer but more diverse parts. At the same time, the prices should not rise despite the increase in different versions and the associated higher expense and effort in production.Up to now, automation solutions could almost only be used for one product. With decreasing production volume, these plants were no longer operating at capacity and were, in some cases, no longer usable for other products at the end of the product cycle. This also meant that a new plant had to be procured for a new product variation.
The idea: An automatic production with the greatest possible flexibility
Against this background, the idea of developing an automatic production emerged which would make possible the production of different products on one plant and with low set-up effort and expenditure.
During a six-month development period, experts from the Söhnergroup and the Battenfeld Company jointly designed the so-called “flexible cell”. After a further six-month construction period, the prototype was ready.
If the product run is reduced, a further variation can be now added in the existing assembly unit.
In contrast to previous automation solutions, existing tools can be used here without modification and a version change can be done in approx. 1 hour. That means that the plant can be used to almost 100% capacity. The expense for customers only amounts to the cost of the part-specific components because the “basic set-up” remains the same.
Trial by fire – passed!
The prototype of the flexible cell was tested using a product line from the Bosch Company.
Different connector housings were injected on a vertical rotary injection moulding machine. The plant is designed so that a change from one variation to another is possible within the usual tool set-up period. This involves exchanging only the components (e.g. inspection station, punch) which are necessary for the new version. Two six-axis robots, a linear unit, the tray changer and the injection molding machine remain as fixed components of the plant.
The concept and the advantages of this automation solution convinced the customer and following the first successful tests on the new plant, a second plant was ordered.
Meanwhile the second “flexible cell” has now been successfully set up at Steffen Söhner in Reinholdshain. Once the plant has been released by the customer, this flexible cell will also begin production.
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