Lean behaviors can often be facilitated by the same stuff. A group that I have been working with has implemented a simple, yet powerful improvement idea that illustrates this phenomena within their low volume, high mix business.  The improvement was instituted to help gain and maintain stability within their mixed model production kanban system. It also provides insight into the root causes that drive some of that instability.

It seems that representatives of the various downstream customers of the in-process kanban (no batch production in the upstream process, the kanban are satisfied in a FIFO manner) were frequently seeking to  move a given kanban to the head of the line…mostly because of their own mismanagement and other barriers. The reshuffle requests were as many as three per shift. It was like an open bar.

Leadership implemented a “passport” system. It’s not really novel, others have applied it. But, it works!

Basically, each of the four consuming departments (with many multiple cells) that are downstream of the kanban are limited to three weekly passes that they can exercise. Each pass entitles the user the opportunity to reshuffle one of the kanbans within the sequence. So, there are rules and there is a finite number of opportunities. No free-for-all here.

There is also also accountability and transparency. The unused passes are hung at a station near the supplying process’ production coordinator workstation. Triggered or used passes are inserted into a locked  lexan box so you can see who has been exercising their passes – the name of the downstream department’s production coordinator is printed on their respective passes. See the picture, below.

Oh, and not all passes are the same. They come with different levels of escalation and, perhaps, pain. The first pass is green in color – essentially a “freebie” that can be used for one priority reshuffle. The second pass is yellow in color and requires the supplying department’s manager to sign-off on the pass. This means that a conversation has to occur…with an explanation as to why the pass needs to be triggered. The third pass is red in color and needs the plant manager’s sign-off for it to be accepted. Few folks want to have that conversation – especially if the root cause is/was within their control.

Guess what? The operation is down to about three kanban priority moves per week and a lot less  volatility. The system works a heck of a lot better now. Transparency, scarceness and accountability have changed behaviors and provided further insight into other improvement opportunities.

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So, when does it make sense to simulate an improvement? We actually do it all the time when we trystorm. Trystorming is a melding of brainstorming and simulation. It can be really simple stuff or it can be much more involved. People tend to be fairly OK with the simple stuff, but start getting weak in the knees when meaty simulation is required. They don’t want to take too much time simulating. It can be slow and tedious.

Simple simulation. People can tolerate simple simulation like pantomiming the new standard work sequence with a draft standard work sheet and standard work combination sheet in hand before they try it out for the first time. Then they can make adjustments on the way. Hey, who wouldn’t be OK with that level of effort and spontaneity?

More extensive. The more extensive simulations take time and require a certain rigor. Why do we need to endure this pain? Because the implementation of improved or brand new systems can cause big problems if we don’t iron out some of the more substantial flaws. Often we don’t know what we don’t know. Here are two types of extensive simulations.

• Many people apply 3P (production preparation process) when developing substantially new or improved processes  and/or products.  As we all know, locking in a poorly designed product or process is a recipe for long-term pain and suffering. In brief, 3P is a team-based methodology in which the members down-select from multiple alternatives to seven different ways for a new improved process (or product), simulate the new process with crude, inexpensive, and quickly applied materials (PVC, cardboard, wood, duct tape, etc.), then whittle down the options to three best process designs (as measured against predetermined selection criteria), followed by more trystorming and then ultimate selection.
• Supermarket pull is a wonderful thing when properly applied, but you’ve got to get it right in order to ensure that the downstream customers are not starved and that there is no excess inventory. Pull system or kanban system simulations are extremely valuable. Using production kanban as an example, after taking a first cut at demand analysis, percent load analysis, determining what the kanban strategy will be (i.e., in process, batch – pattern, batch board, triangle), sizing the kanban, formulating the draft standard work (how/who/when regarding kanban posts, emergency kanbans, scheduling protocol, etc.), etc., we need to simulate the system using real historical demand data and some invented surprises.  The simulation requires cards for all of the inventory, mock kanban posts, “scheduling,” capacity analysis…the whole nine yards! It is critical to find out when and where the system breaks in a big way and then figure out what needs to be adjusted…before it goes live.

So, what are your experiences with either high intensity simulations or implementations where it would have been a good idea to simulate (or simulate better)?

Related posts: Kaizen Principle: Be like MacGyver, use creativity before capital!, Check Please! Without it, PDCA and SDCA do NOT work.

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