REDESIGN OF A MANUAL ASSEMBLY
Corona crisis, blockade of the Suez Canal by a container ship, Ukraine war, 100% lockdown Shanghai. All of this is affecting supply chains around the world. Despite all the supply bottlenecks in raw materials, a manufacturer of industrial fans in the Karlsruhe area is recording steadily growing incoming orders. This is increasingly leading to barely acceptable delivery times for the customer. One of the manufacturer's strengths is its wide range of variants and products tailored to customer requirements. The existing assembly islands are mainly specialized on certain product groups and are not very flexible. As part of the OPEX project, the existing assembly concept is to be revised. Efficiency is to be improved in the double-digit range in order to meet demand.
At the beginning, a value stream mapping gave us an overview of the overall situation. In the next step, we conducted a screening of various assembly islands using standard work workshops. Here, the high proportion of movement and transport activities of the assemblers was particularly noticeable. The assembly procedure also varies from employee to employee. We introduced a tally sheet in which the assemblers recorded the type and duration of assembly interruptions. The list substantiates the observations from the standard workshops. The resulting Pareto shows transport of parts in first place with more than two working days per month. Picking errors follow in second place at about five hours. This means that faulty parts are delivered, which then have to be replaced again by logistics, and that is how long assembly takes.
With this knowledge as a basis, we went back and designed a future-proof concept. The dimensions of the production hall were transferred to a white paper, workstations and equipment were mapped to scale. This allowed us to move everything around on a "greenfield" basis and to design and discuss various scenarios. The layout finally selected for follow-up includes one line each for small and large equipment. In addition, bypasses are provided for spare parts assembly and special constructions. Material is supplied and removed exclusively via conveyor and roller belts, thus almost completely minimizing walking and transport distances for the assemblers. All workstations are standardized and can assemble all equipment variants within the line. The final test is clocked at 3 minutes at each of 4 test stations. One-piece flow with batch size 1 is implemented in paperless production. Of the approx. 600m² production area, approx. 100m² remain as free space for expansion in case of future growth.
In order to avoid a long standstill of the assembly, the concept is divided into phases. In the first phase, a subarea is implemented to verify the concept and optimize processes. The second phase then involves the conversion of the remaining workstations. Finally, the "paperless production" is implemented.
The complete conversion with tests and adjustments can be implemented within one year and enables the customer to increase its output noticeably in the double-digit percentage range.