Sometimes We Remove Technology

I consulted in a plant that had a large machine that cut rubber tubing into pre-determined lengths. Next to the machine, I spotted a large wire container with cut tubing lengths.  It was labeled with a red tag with the word REJECT visible from twenty feet away.  The detail on the tag revealed that the tubing contained in this container had been cut too short.  It was probably going to have to be scrapped.

I asked why the tubing had been cut too short.  Probably human error in setting the machine, I was told.  The specs were not entered correctly and no one noticed until a full container had been cut.  We formed a work group to find a way to prevent this problem from every happening again.

We discovered that the internal customers for these products were two assembly lines.  Tubing that was too long could easily be cut down to size.  Tubing that was too short could not be used because it did not reach the two points in the assembly that needed to be linked. 

We quickly came to the idea that the tubing was quite easy to cut, so why not cut it just-in-time.  The team designed a guillotine (actually a small paper cutter), mounted it on a bench with a channel and a stop that measured the tubing to the required length, making it easy to cut just one piece when it was needed.  The roll of tubing was too large to have on the assembly line.  We cut off enough to supply the line for one day and rolled it onto a smaller reel.  Our arrangement worked well for a week on the first line. After that we duplicated the process on the second line.

Later the company negotiated with the supplier and was able to get tubing in smaller rolls suitable for putting directly on the assembly line.  Within the company there was some resistance to taking a “perfectly good” machine out of service, when it was still being paid for.  When I toured plants in Japan that were practicing lean manufacturing and continuous improvement, I saw several yards filled with equipment covered by tarps.  We were told that this was equipment taken out of service by efforts to make processes lean and reliable.

Lean Manufacturing Requires Responsive and Reliable Maintenance

Lean operations require maintenance that is responsive and reliable.  When we have isolated operations that are adding value to pieces in a batch that eventually gets passed on to another operation, one machine going down does not present itself as a critical event.

If we have many operations organized in a cell and one piece of equipment breaks down, the entire cell goes down.  We require equipment that does not go down very often – ideally not at all – and when it does go down we need to get it up and running as quickly as possible.  This imposes requirements on the maintenance system. The maintenance system is not limited to the maintenance function.  The system includes standard procedures that are followed by the operators and equipment that does not breakdown and/or can be repaired quickly.

A good way to begin to improve the maintenance system starts with a workshop focused on a single piece of equipment that is or will be critical to a lean, one-piece-at-a-time operation.  The workshop team goes through a process of detailing the machine.

What Else Gets in the Way?

Sometimes managers who are very enthusiastic about their kaizen experiences can be the obstacle to improvement in the kaizen way. At one factory the plant manager was one of the most enthusiastic people whom I had ever met.  After a couple of successful workshops with gratifying results he was ready to have “a kaizen event a week.”

This became a problem for one of the reasons I have already mentioned. The support systems for the new, lean, one-piece-flow, work to takt time approach were not in place.  The maintenance system could not respond when equipment went down.  There was not a system of supplying materials in small amounts.  Water-spiders from the early workshops would get drafted to do production work to cover for absenteeism.  Many of the products were fairly low volume, but suppliers brought in huge amounts of components.

What Get’s In the Way of Successful Kaizen?

A dirty little secret is that kaizen efforts often go nowhere, or don’t go very far. In too many cases I have seen very successful kaizen workshops or kaizen blitzes seem to be huge successes, only to have them fade within months or even weeks.

 What do I mean by successful workshops?  A team focuses on a work group or operation.  With the help of a facilitator they identify and figure out how to eliminate waste. The facilitator, who may or may not be an outside consultant, teaches how to look for waste and the strategies to accomplish its elimination. These include moving operations closer together, moving the operations into a U-shaped cell, doing away with batch processing and putting one-piece-flow in its place, and balancing the operation with takt time and cycle time studies, to name a few. The team figures how to accomplish these ideas in this particular case. 

At the end of the workshop, there is a dramatically different situation.  Fewer people are required to produce the same amount. Throughput time is drastically reduced.  Quality is documented to have substantially improved. Everyone agrees; this is better.  This is great stuff.  (Another example might be a SMED workshop that cuts changeover time from over two hours to forty five minutes.)

Why Not Manufacture in Easy Batches?

During a workshop, a manager resisted the idea that batches are always to be avoided if possible.  He used the example of paying his bills by check (this was before the days of online bill-paying). It was easiest for him, he said, to sit down at the kitchen table, open all the bills and take them out, write all the checks, stuff all the envelopes, put stamps on all the envelopes and drop them in the mail.

I asked the group if there was anyone present who had ever sent the wrong check to a payee.  A couple of people admitted that it had happened to them.

If you practice one-piece-flow, processing one unit at a time – in this case one bill—you practically eliminate that particular mistake.  You open one envelope, read the bill, write the check, put it in the envelope with the bill stub, seal the envelope and put a stamp on it.  If you wait to put stamps on the envelopes until all have been sealed and stacked, there is more of a chance of skipping an envelope and mailing it without a stamp.

Takt Time

One of the concepts used by companies that are moving toward leaner operations is takt time.  It is also a concept that is often misunderstood in companies that have had a little exposure to lean processes and have picked up the term.

Takt time is the beat at which we should make a product or component to be in synch with the needs of the customer. The customer may be an internal customer such as a downstream process, or it may be an external customer, a dealer or an end user. Takt is a German word for beat when the subject is music.  The baton used by a band or orchestra leader is called a taktstock.

Let us suppose that a customer of any type needs 900 units, widgets of some kind.  The factory works an 8-hour shift, but a half hour a day goes into breaks and other planned downtime, leaving 7.5 available hours.  Seven and a half hours times 60 minutes, times 60 seconds, equals 27,000 seconds of available time in a shift.  If we divide 27,000 seconds into 900 units, we find that our takt time is 30 seconds per unit.  To be perfectly synchronized with the customers requirements for a day, we need to produce one widget every 30 seconds and each operation in the process should take exactly 30 seconds.

Keeping it Simple

We often overcomplicate things at work.  Complicated machines become obstacles to getting the job done.

In one factory, a large, highly automatic machine spun nuts onto threaded nipples.  The operator’s job was mostly to catch defective nut-to-nipple assemblies as they came out of the machine and set them aside for later repair.  If practically all of the assemblies were defective, because the nut had not been spun on straight and had jammed onto the nipple, he shut down the machine, tried to make adjustments to it, and generally ended up calling maintenance.  While maintenance tinkered with the machine, the operator would sit at a workbench and use channel locks to removed jammed nuts from the nipples, so that both parts could be put back into the machine. 

Sometimes, there were so many flawed assemblies, additional workers would be brought to the area, given channel locks and put to work undoing the bad assemblies.

I worked with a team of workers and managers on an improvement project that made this problem go away. We purchased two nut drivers with sockets sized to the nuts in question.  The nut drivers were of the type that activate when you press down on the nut, and stop when you release the pressure.  We mounted these upside down, side-by-side, in the center of a small workbench.  We fashioned some brackets to hold them with the sockets flush with the tabletop, through holes in the center of the workbench.  We had a bin with nuts and a bin with nipples on the workbench. The operator would take two nuts and slide them into the sockets.  He would then take two nipples and briefly press them into the nuts in the sockets. This activated the drivers to spin the nuts onto the nipples.

Management Gets More Than It Deserves

In the factories that I visit, I find that management often gets more than it deserves from the production workers.  I remember a woman at a workbench, taking four parts from bins and using a machine to drive a rivet through all four to make a sub-assembly for a circuit breaker. She did this over-and-over, but her rhythm would often be broken because one of the parts had the hole for the rivet off location and therefore would not go together easily with the other three.  She would struggle to make them go together, and sometimes succeed in forcing the rivet through all four parts.  Other times she would eventually set aside the defective component and reach for a replacement, which, all too often, would also be so far out of spec as to be unusable.

One Place to Get Started

There is not one way to start moving toward organizational excellence.  Here is one approach to getting started.

Learn to look at your organization with new eyes.  Where is the activity that does not add value to the product?  The amount of activity that does not add value can be thousands of times of the amount of activity that does add value. Figure out how to eliminate activity that does not add value.

For example, transportation of material does not add value.  Of course, product has to be moved from one operation to the next, but often we increase transportation by having unnecessary space between any two operations.  Because we have the space, we don't move each piece to the next step immediately, we allow the product-in-process to accumulate in containers, to the point where it can no longer be moved by hand.  Now we need a forklift to come and move the container.