In my last post, I began presenting a problem-solving case study on a company that manufactures stainless steel pressurized vessels. In Part 1, I laid out the background information about this company and began using the problem solving roadmap.
I also developed the team’s problem statement, which was:
Pinholes and weld spatter are occurring on 100 percent of the stainless steel tanks at a rate of approximately eleven hours per day, creating significant amounts of rework. Based upon a recent study, as many as 100 hours per week of rework time have been observed for these two problems, and the trend is constant.
Continuing with applying our problem solving roadmap to weld spatter and pinholes
In Part 2 of this series, I will continue with the step-by-step method for solving the problem involving weld spatter and pinholes. As I stated in my last post, it is important to understand that when we solve problems, there are often positive side benefits that we may not have anticipated.
2.0 Select a success metric
Now that all members of the team understand the problem in exactly the same way, they can begin the process that will ultimately lead them to the root cause and corrective action. It’s important that the team is able to understand if their apparent solutions have a positive impact on their problem. In other words, how will they know if what they are doing has resulted in a positive impact? They will be able to know by selecting what I refer to as a success metric. The team chose to measure the amount of daily rework hours per day.
II. Investigate, organize, and analyze the data
The next step for the team to accomplish was to investigate the problem, in much the same manner as a police force would investigate a crime. There are clues and bits of evidence at the scene of the crime that, when assembled in a logical and structured fashion, will lead the team of investigators to the root cause of these problems. So the team investigated, organized, and then analyzed all of the pertinent and relevant information.
3.0 – 4.0 Record the symptoms and relevant data
Symptoms are the warning signs and signals that something has gone out of kilter or is amiss. Just as a doctor records things like temperature, blood pressure, or visual abnormalities, so too must the team look for outward signs that things are not as they might be or should be. As a group, the team reviewed the process of making tanks and recorded various observations and then met to discuss their findings as follows:
- There was a noticeable and inconsistent gap between the tank and the structural rings, prior to welding the rings in place. Where the gap existed, there was an excessive amount of weld spatter present.
- Not all welders were operating at the same speed setting.
- The tanks were located on variable speed floor mounted rollers that turned the tanks as the welds were made. The turning speeds were not the same for all tanks.
- As the tanks turned on the rollers, often there would be a jerking or slipping action. This tended to speed up and slow down the tanks during the welding of the rings.
- The anti-spatter material used was not applied consistently by all of the weld operators.
- Not all welders were using the same welding wire type.
- The welding angle used by the welders was inconsistent from operator to operator.
- The legs on the rings did not appear to be symmetrical from side to side.
Coming in the next post
In Part 3, we will continue working our way through the various steps in our problem solving roadmap.
Until next time,
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