Lean Factory Simulation

Lean Factory Simulation Card Exercise

Objective:

To demonstrate in a short simulation the benefits from lean thinking.

Material:

3X5 index cards, minimum of 300. letter size envelopes, 50 minimum. masking tape; writing instruments, pencils or ballpoint pens. flip chart and felt tip pens. Several tables or desks. watch, preferably a stop watch, but a wristwatch with second hand is ok.

Roles:

Production workers-- 3 or 4 depending upon the size of the group Warehouse person- raw material ; Material handler; Final inspector; Customer Timekeeper

Setup:

Place tables apart in a large room or use desks/tables in adjoining rooms. Assign each production worker, the warehouseperson and final inspector to a table or desk. None of these should be adjoining (i.e. simulating a factory laid out in machine colonies.) Place the customer at his or her own table in the vicinity of those persons in the group who are not participating in the simulation and a distance from the final inspector. The timekeeper can be with the observers as well. Material handler is obvious below.

Simulation:

The product is an index card with each production person's name on it. To keep the time short, use only first names on the cards. The customer will accept as many of the signed cards as the factory can produce.

The workers make a sample (prototype) and get agreement from the customer. This is the product specification card and subsequent “product” should match this card exactly.

1/9/18 DNHanink Consulting page 1 of 4 Run #1:

The batch size is 10 cards. The envelopes are the material handling totes. The length of the simulation is 3 or 5 minutes depending on how much time for the training is available.

The timekeeper signals the simulation is to begin. The warehouse person picks 10 cards from his or her raw material inventory and places them into an envelope. The material handler takes it to the first production worker.

Production worker #1 removes the cards from the envelope, signs his name on each card, and places the cards back into the envelope. The material handler takes this batch to Production worker #2, who does the same thing as worker #1. The batch is mover to worker #3 and so on until the batch is finished. Then, the material handler takes the batch to the final inspector, who checks each card against the spec card. If they are OK, the material handler takes them to the customer. The customer checks the cards to see that they match the spec card (prototype) exactly- accepts them if they do; rejects if not.

As this is a push system, the warehouse person begins picking a second batch as soon as the material handler carries away the first batch, and continues picking and making batches as fast as he can. As each batch is ready he signals the material handler to return to move the batch to the first production worker. (The customer will take as many products as the factory can make so everyone has to work as hard as possible, right?)

The material handler is moving among all the stations moving card batches, not necessarily in the order of the production steps. Each worker is trying to move as many cards through his or her operation as possible. The material handler usually is walking briskly among the tables.

At the end of the 3 or 5 minutes, the timekeeper signals the factory to stop production. All cards are stopped wherever they are.

On the flip chart, the session facilitator creates columns for data to be collected. Specific results for each simulation will be entered in rows on the chart. The data captured are these:  number of workers;  # of pieces received by customer;  # of pieces good versus bad at the customer;  work-in-process; # of in-process rejects.  distance traveled by the material handler.

After collecting the data from Run #1, the facilitator announces that the second simulation will have a batch size of 5. He or she asks for suggestions to improve the factory prior to the next run.  Usually someone will suggest moving the workers together into a production line. This substantially reduces the material handler's task. Sometimes participants suggest combining this job with the inspector's.  Someone may suggest combining the first production step with the raw material inventory. 1/9/18 DNHanink Consulting page 2 of 4  There may have been quality problems because people were rushing during the first simulation. Sometimes the group will suggest a need for a roving floor inspector- this could be the material handler’s or warehouse person’s new assignment.

Run #2:

Again the factory is operated for 3 or 5 minutes with a 5 piece batch size. Again the customer will accept as many cards as the factory will produce as long as they are exact matches of the prototype. At the end of the 3 or 5 minutes, collect the same data again and enter it on the flip chart.

Ask for observations. Usually there has been some improvement in performance. At least the material handler has not had much to do, if the job has not been made redundant (Retrain material handler for another task – sales or?). Facilitator notes the improvement percentages.

Facilitator asks for suggestions to improve the factory. Sometimes there are unanticipated events, especially around quality, that require discussion and corrective action.  Often, especially in non-union shops, someone will question the need for any inspectors. If each person is responsible for his or her quality, then no inspector is required. Spec cards for each process step or some other one piece lesson is then required.  Often someone will suggest that the customer and factory should be co- located.  Someone may suggest making and passing one piece at a time. And if so, then the need for the totes (envelopes) is questioned.

Make the suggested changes. If someone has not made the last recommendation, then the facilitator sets up the next simulation this way- i.e. passing one piece but still a push system.

Run #3:

Again, run the factory for 3 or 5 minutes. Collect the data and compare with the preceding simulation runs. There should have been a significant improvement in productivity by virtue of producing more good cards with fewer people. There should have been less WIP, much shorter distances and better quality results.

Run #4: To this point each simulation has used a push production system. The facilitator sets up the next simulation to be a pull system.

The facilitator uses the masking tape to mark a box on the table between each operator and between the last operator and the customer. A card finished to that point is placed in each location. The facilitator instructs the workers to only perform their operation when the box with the card they finished is empty and, then, to just make one card for the box. The customer begins the simulation by pulling the finished card from the box next to the last

1/9/18 DNHanink Consulting page 3 of 4 worker and then each operator successively replaces the card as the following operator or the customer consumes them.

Run the simulation again for 3 or 5 minutes. Collect the same data and contrast it with the previous runs. After subtracting the beginning WIP, the production should still be better than the single piece push system. (Runs #3 and 4 can be shorter than #1 & 2 as the output is usually substantially better than #1 &2. But then the results need to be stated in terms of the man-minutes consumed by each factory run.)

Discuss the results with the entire team. Ask how the operators felt during the various simulations. In all likelihood they will agree that the pull system was a less hectic "factory" condition than the others were and they will probably be surprised to see that they actually out performed all of the other simulations.

Final Notes:

This simple simulation captures the essence of the lean system. It dramatically shows how production can be increased, yet quality improved and inventory, floor space and travel distances reduced. The facilitator should relate this to the elimination of waste.

It is possible to enhance the simulation if that is desired. Using different colored index card stock and different colored ballpoint pens could produce more complex products. The pens could be used to introduce a setup feature if the different colored ink cartridges needed to be assembled into the pens for the first and second simulations.

Scrutinizing the handwriting and dog-earing the index cards can make a bigger issue around quality. This would be to reinforce the need for process controls and the responsibility of each worker to do a good job.

The facilitator needs to be prepared to deal with the people/jobs that become redundant during the simulation. Potential answer: retrain for other available jobs; set up additional production lines to make more product for the customer or other customers; put folks into a temporary kaizen offices to assist with other improvements; or if these are really not feasible, then saving remaining jobs reluctantly may have to be the answer.

Frankly keeping it simple usually is best. It is not a perfect simulation, but in a very short time, usually 60 to 75 minutes, the workshop members can apply the five principles of Lean Thinking and actually experience the results. Participants are usually amazed at the results.

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