A manufacturer of aluminium cabinets (built-in cabinets in vehicles) delivers 50 cabinets per day to a customer. The fluctuation is 25 pieces per week. The customer demand must be 100% fulfilled.

The processing time per cabinet is 20 minutes in machining (3-shift operation possible), 24 h for 55 cabinets in coating (incl. drying time) and 0.5 h in assembly incl. quality inspection. In assembly up to 4 workstations can work in parallel. After assembly there is a buffer of up to 25 cabinets. A buffer of one daily quantity should be available before each processing step. One cabinet per day is sorted out due to quality defects in assembly. There are no other quality problems.

There is space on a load carrier for the parts of up to 15 cabinets (without necessary C parts). The load carriers are loaded after machining and then serve as load carriers until assembly.

For your calculations, assume 20 working days / 4 weeks per month and an equally distributed working time of 40h/week.

a) How many Kanban are needed for the system?

b) What is the maximum stock in circulation?

c) How would you provide standard parts, e.g. screws and hinges (classified as CXK in the supply concept) in the assembly? Explain your decision.