We often blame the old machine when we have a quality problem. This old thing doesn't work like it used to. At some point, we end up buying a new machine. But the problem wasn't the entire machine. Some part of it had failed or worn out. The machine ought to have a much longer life when you replace worn parts. The trouble is, a lot of people give up the hunt for the elusive broken part of the machine.
A company I worked with was dispensing fine powders as a part of one of their processes. The reject rate was too high because the amount of powder dispensed was sometimes too much, other times too little. The problem was in the variability of the dispensing process. A new, half million-dollar machine was purchased to replace the old machine and for a while, both machines worked side-by-side. Now get this. The new machine was worse than the old one! More overweight rejects. More underweight rejects.
I was able to work with the company on this specific project and we determined the root cause of the old machine's variability problem. It was corrected and was producing over 99% quality product (up from 85%!) in a few weeks. The new machine was significantly different and required some pretty serious redesign work. My contribution was over and I moved onto other assignments but I hear from people still there that the new machine is in the corner. No longer needed.
Old machines don't fail. Parts of it wear. The root cause of many old machine problems turns out to be a hundred dollar part. It's well worth spending the time to figure this out.
Wednesday, August 27, 2008
Collect the Evidence
All manufacturing companies have quality problems. These problems typically consume 15 to 25% of sales revenue. Problems of this magnitude must not be treated lightly. A sound, structured approach is necessary or the problem will just continue to bleed.
The first task is to meet with the smart people in the company and discuss what could possibly be going wrong. There's value in this because it may be a known problem, something that has happened in the past. But once you have checked the obvious, other ideas are just opinions and best guesses and they are likely to waste more time. It's important to keep in mind that the meeting can only bring up existing knowledge. If there's something new or unexpected happening, it's not likely to be identified in a brainstorming session. There are hundreds of things that could be going wrong but only one or two actually are going wrong.
All processes communicate their behaviour. The problem is that we do not speak the same language. We need to use tools to tap into this 'voice of the process.' In my experience, when you tap into this voice, you always learn something new.
As an example, if your process is a dispensing process, start taking before and after weights to better understand the dispensing process. Learn how the process varies from item-to-item, shift-to-shift, week-to-week. If you use ovens, use thermocouples to see how temperature varies from top-to-bottom, front-to-back and over time. I've used tachometers before to measure the speed of a moving conveyor. The belt speed was set to 30 feet per minute but the tachometer showed us that the belt was getting hung up somewhere and the belt speed would stagger a little. Not visible by eye, but measureable with the right tool. And the stagger was the root cause of a quality problem we were chasing. This was not identified in the initial brainstorming session.
Use measuring tools to learn about process behaviour. Evidence trumps opinion when you're solving quality problems.
The first task is to meet with the smart people in the company and discuss what could possibly be going wrong. There's value in this because it may be a known problem, something that has happened in the past. But once you have checked the obvious, other ideas are just opinions and best guesses and they are likely to waste more time. It's important to keep in mind that the meeting can only bring up existing knowledge. If there's something new or unexpected happening, it's not likely to be identified in a brainstorming session. There are hundreds of things that could be going wrong but only one or two actually are going wrong.
All processes communicate their behaviour. The problem is that we do not speak the same language. We need to use tools to tap into this 'voice of the process.' In my experience, when you tap into this voice, you always learn something new.
As an example, if your process is a dispensing process, start taking before and after weights to better understand the dispensing process. Learn how the process varies from item-to-item, shift-to-shift, week-to-week. If you use ovens, use thermocouples to see how temperature varies from top-to-bottom, front-to-back and over time. I've used tachometers before to measure the speed of a moving conveyor. The belt speed was set to 30 feet per minute but the tachometer showed us that the belt was getting hung up somewhere and the belt speed would stagger a little. Not visible by eye, but measureable with the right tool. And the stagger was the root cause of a quality problem we were chasing. This was not identified in the initial brainstorming session.
Use measuring tools to learn about process behaviour. Evidence trumps opinion when you're solving quality problems.
Monday, August 18, 2008
Sample Size
A manufacturer recently recorded 14 test failures out of a total of 318 products submitted for testing. This failure caused some panic and with it, some hasty decisions. Root cause analysis was performed in a meeting room. Wrong place. A decision was made to modify some tooling on the assumption that this was the root cause. With the new tooling in place another 30 samples were submitted and all passed the test. And there was much rejoicing.
The sample size was wrong. The problem still existed and there was a lot more product in inventory because the group celebrated early, producing a lot more units with both the modified tool and the real root cause.
The sample size chosen only provided 75% confidence, not enough for such an important decision.
There are many reasons why problem solving efforts fail. Knowing the minimum sample size required is one of them and it shouldn't be.
The sample size was wrong. The problem still existed and there was a lot more product in inventory because the group celebrated early, producing a lot more units with both the modified tool and the real root cause.
The sample size chosen only provided 75% confidence, not enough for such an important decision.
There are many reasons why problem solving efforts fail. Knowing the minimum sample size required is one of them and it shouldn't be.
Quality Resources
Most manufacturers that I have worked with over the years have a small band of Quality department employees. A Manager, one or two engineers, an auditor and a couple of technicians and inspectors. The output from such a department tends to be a fair amount of Quality administration such as ISO 9001 registration documentation.
But the job of each department in the organization is to prioritize economic performance and Quality administration doesn't cut it. The Quality resources must be responsible for problem solving. Not just identifying them and issuing additional documentation (CARs, NCRs, etc.) but actually resolving the company's top problems. Solving the top few problems in a company will put at least 10 points back to the bottom line. That's how to allocate your Quality resources.
But the job of each department in the organization is to prioritize economic performance and Quality administration doesn't cut it. The Quality resources must be responsible for problem solving. Not just identifying them and issuing additional documentation (CARs, NCRs, etc.) but actually resolving the company's top problems. Solving the top few problems in a company will put at least 10 points back to the bottom line. That's how to allocate your Quality resources.
Tuesday, August 12, 2008
Similarities in Quality Problems
Manufacturers view their processes as unique and so they see their problems as unique. But when you step back from this focused viewpoint and see these activities from a cross-industry perspective, they’re very much alike.
I’ve worked in a lot of manufacturing companies and their processes are all the same. Raw materials are purchased according to schedule. Incoming inspection approves them for use. Parts are fitted, formed, welded, trimmed, heated, cooled, measured, assembled, tested, packaged and shipped against orders. Even at the detailed level of the processes we see many similarities. Vibratory feeders, ovens, conveyors, dispensers, laminators, presses, welders, adhesives, rotary tables, lasers and more. Similar processes show up in companies manufacturing very different products. Quality problems that show up in different companies also tend to be similar.
Develop your problem solving capabilities. When you are good at problem solving, you can make a huge difference in your company.
I’ve worked in a lot of manufacturing companies and their processes are all the same. Raw materials are purchased according to schedule. Incoming inspection approves them for use. Parts are fitted, formed, welded, trimmed, heated, cooled, measured, assembled, tested, packaged and shipped against orders. Even at the detailed level of the processes we see many similarities. Vibratory feeders, ovens, conveyors, dispensers, laminators, presses, welders, adhesives, rotary tables, lasers and more. Similar processes show up in companies manufacturing very different products. Quality problems that show up in different companies also tend to be similar.
Develop your problem solving capabilities. When you are good at problem solving, you can make a huge difference in your company.
Sunday, July 27, 2008
Solving a Quality Problem
Most efforts at solving a quality problem start in the boardroom and unfortunately spend too much time there. This is where we brainstorm and throw our ideas on the table for review. The place to be when you're trying to solve a quality problem is on the factory floor where the problem is created. Like a detective trying to solve a crime, you need to be at the scene of the crime and collecting clues. This sounds obvious but it is surprising how infrequently people take this approach.
I was working with a group in China a few years back and there was a quality problem that caused significant numbers of their product to fail and they had not been able to determine the root cause. Upstream in their process was a 12-station rotary table that was used for swaging (forming metal). There were no labels on this rotary table identifying station 1 vs 2 vs 3 etc. So we labelled them 1 to 12 and then took items off the process and lined them up in several rows of 12. It was there right in front of us. Station #5 produced terrible product. The company management was impressed with how quickly we resolved a long-standing quality problem.
Brainstorming doesn't work. Gathering evidence does.
I was working with a group in China a few years back and there was a quality problem that caused significant numbers of their product to fail and they had not been able to determine the root cause. Upstream in their process was a 12-station rotary table that was used for swaging (forming metal). There were no labels on this rotary table identifying station 1 vs 2 vs 3 etc. So we labelled them 1 to 12 and then took items off the process and lined them up in several rows of 12. It was there right in front of us. Station #5 produced terrible product. The company management was impressed with how quickly we resolved a long-standing quality problem.
Brainstorming doesn't work. Gathering evidence does.
Monday, July 21, 2008
Quality Problems in Manufacturing
In 2005, CME's 20/20 Magazine published results from a Management Issues Survey. The least satisfactory skill set among employees in Manufacturing was Problem Solving. 
All manufacturers have quality problems. Plenty of them. We tend to assign these to our technical employees assuming that they possess the required skills. Engineers will certainly have strong math skills and engineering intuition. But this isn’t enough. There are other elements of problem solving that need to be known such as nonparametric statistics, variation reduction strategies and components of variance techniques. Problem solving is a skill that can be learned. It’s important, indeed necessary, that manufacturers develop problem solving skills among their employees and dedicate a small team to doing nothing else.
All manufacturers have quality problems. Plenty of them. We tend to assign these to our technical employees assuming that they possess the required skills. Engineers will certainly have strong math skills and engineering intuition. But this isn’t enough. There are other elements of problem solving that need to be known such as nonparametric statistics, variation reduction strategies and components of variance techniques. Problem solving is a skill that can be learned. It’s important, indeed necessary, that manufacturers develop problem solving skills among their employees and dedicate a small team to doing nothing else.
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