Lean & PDCA (Part 2)
Tuesday, December 27th, 2011In the previous post, I outlined how lean projects can be manged through Plan-Do-Check-Act (PDCA) cycles. Here, I’ll be walking through an example.
Plan
This step includes drawing current value stream (VS) map in terms of processes (or activities), calculating processing times on the value stream, and analyzing for waste. After conducting some brainstorming, the PDCA team can list opportunities for removing such waste by reducing, re-organizing, realigning, training. Finally, we prioritize such opportunities start implementation with those with highest impact first.
In this example, a pizza shop takes orders for delivery over the phone and processes manually. Customers complain about delivery time being long. Here is how the process works:
- The order taker writes down all order information (type of pizza, size, ingredients, ..etc.) as well as the address.
- Order gets verified by the manager before forwarded to the kitchen. In case of any missing information, the order taker calls the customer back for corrections
- Prepare pizza
- Pizza sits in queue before baking
- Bake, cut, package and label pizza
- Pizza waits in warmer for delivery
- Deliver pizza
The goal here is to eliminate all complaints due to “long delivery time”and increase customer satisfaction.
Times form the above value stream can be summarized as follows:
Lead Time: The time from the customer calling in until the pizza is delivered. In this example, the Lead time is 44 minutes.Value-Adding: All activities that add value to what the customer experiences / pays for. Those steps amount to 15 minutes which is about 34% of the lead time.
Delays / Waiting amounts to 8 minutes.
The PDCA team has conducted root-cause analysis to eliminate waste (and shorten delivery time). The team decided that the manual system for orders created delays and inefficiencies. So it was decided to implement a computerized system for entering orders and communicating them to the kitchen using computer monitors. Also, it was decided to hire an additional delivery driver. The future value-stream table is expected to look as follows:
Do
- Prepare and implement action plan for computerized system
- After implementation, let the system run and stabilize
- Collect delivery times data again for measuring progress
Check
- Data analysis after implementation of plan show a reduction of lead time by an average of 11 minutes. This is a reduction of approximately 25% of lead time.
- Complaints due to long delivery time were reduced by 60%.
Act
The updated value stream after implementation will become the “current” for the next PDCA. As can be seen from the updated value stream table, delays due”waiting for oven space” and “waiting for driver” are still there and could be minimized or eliminated by coming up with efficient methods and creating additional capacity.
Mustafa Shraim