The Over-Packed Dispatch Bench
A mail-order pharmacy fills prescriptions at a single bench. The team prides itself on keeping every station stocked. At the packing bench, a clerk spends the first 20 minutes of each shift pulling 300 padded envelopes from a store room 40 metres away and stacking them beside the seat. The bench holds 320 envelopes, so the stack is refilled once more mid-shift. Prescriptions arrive in batches averaging 45 per hour, but the clerk can pack only 40 per hour, and the backlog grows until a second clerk is pulled from labelling at 2pm each day. The labelling area then falls behind. The manager's proposal is to buy a second packing bench and hire a part-time stocker to keep envelopes topped up so the clerk never leaves the seat.
1. Classify the envelope stock, the walk to the store room, and the 2pm reassignment of the labelling clerk. Which are waste, and of which type?
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Envelope stock beside the seat. Inventory waste. 320 envelopes is roughly seven hours of demand at 45/hour; it is buffer stock hiding a supply problem (the distance to the store room), not value-adding work.
The 40-metre walk. Transportation and motion waste. Material is being moved further than the process needs, and the clerk's body is moving without advancing the prescription.
The 2pm reassignment. This is not waste in itself; it is a symptom. Pulling a labelling clerk to packing creates a new bottleneck upstream. The underlying issue is a capacity imbalance (40 packed/hour vs 45 arriving/hour), which is a waiting/backlog problem, not a staffing problem to be solved by borrowing.
2. Evaluate the manager's proposal against Lean principles. What would a Lean thinker do instead, and what would you measure to prove it worked?
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The proposal adds waste rather than removing it. A second bench plus a stocker institutionalises the transportation (someone now walks envelopes for a living) and adds inventory and an extra pair of hands to a process whose real constraint is a 40/hour packing rate against 45/hour demand. It also spends capital before the cause is understood.
Lean alternatives, in order of preference:
- Move the supply closer - relocate envelope storage to the bench, eliminating the walk and most of the buffer.
- Attack the 5/hour gap at the constraint - observe the packing step for the largest time losses (reaching, searching, double-handling) and standardise the work.
- Level the arrival of work if batches can be smoothed, so the bench is not hit with 45/hour surges.
- Only then consider adding capacity.
Measures to prove it: hourly throughput at packing, backlog at 2pm, number of labelling reassignments per week, and distance walked per shift. Success is the labelling clerk staying in labelling and the backlog not forming - not a tidier bench.