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Although Variass has a delivery reliability of 98%, the production process has a couple of characteristics which make control difficult. In total, 600 different products are delivered that are produced over more than 100 different product routings. In addition, the order sizes vary between 1 piece per order to 2000 pieces per order. Furthermore, the occupation per operation varies between 0 and 160 hours and processing times vary between 1 and 300 hours. These characteristics has led to three central problems:
- Orders stagnate 80% of the time;
- Problems with regard to capacity control within the independent working cells. Due to the varying order mix, capacity needs to be exchanged between cells constantly;
- Lead times are irregular.
In 2010, a POLCA-scan took place to assess the suitability of POLCA within the assembly department of Variass Veendam. To reduce variability, an overview of the inter-cell traffic between several cells was designed. Eventually, a schematic overview with the most important POLCA-loops was established. These POLCA-loops capture 91% of all order flows.
Since
the variety of products, production times and production routings are too high
to just use POLCA as it is, the design team of Variass made adjustments to make
POLCA fit for their purpose. They decided to link POLCA cards to cells instead
of different POLCA loops. In addition, it was chosen to use one central POLCA
board, centrally located and accessible to all cells. The information on this
central POLCA board helps to make sequencing and dispatching decisions in the
cells and provides information about the staffing within each cell. A
combination of this information helps the production manager to decide whether
it is necessary to move employees from one cell to another. The figure below shows the central bulletin board which indicates staffing information along with POLCA cards indicating the need for jobs. The manager is pointing to the number of workers in a particular cell.
