Company X now had substantially reduced the number of no shows on their schedule. The new upper control limit was three [3 times the square of the mean,] down from six. This meant they could now schedule their time more accurately, which resulted in more clients served per week.
Wheel alignment was a major part of the company’s business at that time. It was reasoned, if the amount of time required to perform an alignment could be reduced, still more clients could be served.
Using the same charting method, the time to perform an alignment was charted. Once the mean and upper and lower limits were established, the system was shown to be in statistical control [no special causes.] To improve the process, the system would have to be improved.
A plan was needed to use Plan, Do, Study, Act (PDSA.) Wheel alignment is not a single thing, it is a large collection of things. When any one goes wrong, whether or not it gets to the client, time is needed to correct the problem. This time is called non-value added (NVA) because it increases cost, without adding value. Without adding value, because if the problem could be prevented, rather than fixed, an equally good or better alignment could be done in less time [money?]
For instance, the company could accurately state their comeback rate is very low. The questions are, very low compared to what and by what method.
It was decided, comparing one company to another or even all other companies would help very little. Having less comebacks than someone else is really not very helpful. Continual improvement was the plan. Continual improvement of the company’s previous best, was a better indicator. No matter the number, there is room for improvement and that would be the plan.
Second, by what method. Company X , at that time, was increasing quality using the method most companies still use today. That is Do, Inspect, Rework and Deliver (DIRD). First the vehicle was aligned. Then it was test driven. Now it was put back on the machine, as needed to perfectly center the steering wheel or remove any pull that still existed. The end product was a vehicle that drove perfectly straight and had a centered wheel. Unfortunately the process was loaded with NVA steps.
To reduce time [cost] a better way had to be found. The process was plotted on an Ishikawa [fishbone] diagram. This diagram, named for its creator is quite helpful in making the steps of a process visible. Many programs exist that can produce this tool or it can easily be drawn by hand. As many causes of problems as could be determined were listed.
It was decided that each part was so inter-dependent that they should all be improved simultaneously. Training men to do a better job would be useless, if their equipment was not accurate and did not repeat.
Time and assets were allocated and the company formed three teams. Each team undertook two of the major headings. Under each heading, the items were subjected to the PDSA cycle. Plan; “What might make this better?” Do; Each plan was implemented and the results tested. Study; Did the results change for the better? Act; If yes the plan was implemented, if no, the plan was revised.
For example, air pressure. All of the gauges in the shop were gathered and tested. It was found they did not read the same. There was no way to know which were right and which wrong. A calibration fixture was built and sent to a local testing lab for verification. Now, it was found many gauges did not repeat. The problem was solved by constructing their own, using higher quality gauges.
Alignment readings were recorded, the car taken off the rack and then immediately put back and readings taken again. The readings were not the same, the machine did not repeat. One thing found was the slip plates did not let the car settle the same each time. The were serviced and service of the plates was added to the maintenance schedule.
How firmly the bolt, securing the alignment head to the clamp, was tightened also changed the readings. Lubricating the rack, with synthetic grease allowed it to settle more consistently. Adding bright colored caps to the grease fittings helped keep dirt out and made them easier to locate. This too was added to the maintenance schedule. A precision level was bought and a good deal of improvement made by precisely leveling the racks.
An in-house calibration fixture was purchased and put to use. Accuracy of the instrumentation could now be measured against this standard. Disassembling the heads, cleaning and tightening the mirrors also made the machine more consistent. A dab of epoxy on each mirror helped the heads hold calibration much better. Several improvements were made until the machines read accurately and repeated consistently.
All alignment techs received specialized training and all at the same time. Their procedures were standardized so each man consistently got the same results as the others.
Many PDSA cycles were run over a six-week period. The results included; Alignment time was reduced 40% with a sizeable reduction in an already low comeback rate. This was accomplished with the same machines, racks and the same personnel. The process continues to this day. The same process can be used to improve the way a client checks in when they drop their vehicle, the way an oil change is done or almost any process in the business.
A few points I would like to restate. SPC, PDSA and the Ishikawa diagram are tools that can be used on almost any process. The goal is to identify and remove as many non-value added (NVA) steps as possible. NVA steps are removed by preventing the problems they [NVA steps] are in place to correct. Where DIRD is used, there will always be non-value added steps and as quality improves, cost go up. The opposite is true with continual improvement. As quality increases, cost go down because of elimination of inspection and rework.
Treating common cause variation as a special cause fills processes with NVA steps. I believe this is largely occurs because of a lack of understanding variation and a lack of the use of SPC. We have all seen companies like this. When anything goes wrong a rule is made, someone is chastised, things are changed and people are changed. Still the problems persist, cost increase and profit drops. When prices are raised, clients are loss and the cycle continues.
These tools have been known and have been proven for many years. The Japanese have largely elevated them to a way of life. In the US these methods are rarely considered for a number of reasons.
Dr. Deming explained these reasons and the cures in his fourteen points. In my next series of post I will try to discuss each of the 14 points, within the limits of my understanding.
Joined: 15 May 2007 Posts: 146 Location: Garden City, KS
Posted: Mon Jun 04, 2007 9:35 pm Post subject:
Awesome...simply awesome. I'm willing to bet that the personel involved in the planning and studying stages were extremely motivated. To feel the freedom bestowed by you to find the best way to perform the service, plus find and eliminate as many NVAS's as possibe would be very enpowering. It would make the Acting (carrying out the revised steps/service(s) ) much easier and effortless because they were involved and decided heavily what actions would need to be taken. And above all, when costs were lowered and profits raised...they saw that benefit as well. Do you have more examples? I'm going to start working on my own fishbone diagram right now! Thanks for the great post Louis! Later, Matt.
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