When critical equipment fails the traditional cry is “Fix It Now!” In most cases, that’s exactly what happens. The equipment gets “fixed” and is up and running. That is, until it fails again. The problem continues and the fixes continue.
The reliability improvement answer is “Troubleshooting” to the point of “Problem Solving,” and then “Problem Eliminating.” Personnel learn from the process and are able to leverage the skills they gain elsewhere.
A site’s work culture, however, defines which of these two approaches is ultimately followed.
TYPICAL SCENARIO
The following is a summary of an actual production process fix-it-now scenario, as explained by senior operators.
1. “When we started the process the diaphragm pump did not start and the fluid overflowed all over the floor. We were shut down for a day cleaning up. Maintenance came and repaired the pump.”
2. “Then, it happened again! The diaphragm pump wouldn’t start in the line startup cycle.”
3. “So, we figured out that the line air pressure had to be cranked all the way up to get the pump jump-started.”
4. “When maintenance came and checked the pump out it was running fine.”
5. “The pump won’t start automatically. We still have to crank the line air pressure all the way up to get it started. Maintenance says there’s a problem in the controls, not with the pump.”
This condition was observed over a six-month period. As the frustrated equipment operators explained, “Every time maintenance showed up we had the pump running. So, they left, blaming the process controls. And, the problem continued almost every time we started the production process.”
LET’S SOLVE THE PROBLEM SCENARIO
This scenario offers a practical hands-on way to teach root cause analysis. In it, we follow a basic scientific method to identify and eliminate the causes of the above diaphragm-pump problem.
(NOTE: This process is not exclusive to pumping systems: A similar step-by-step approach can be taken with other categories of plant equipment.)
1. Go look at the pump. Talk to the operators. Observe the startup problem. Verify the description of the problem: “Diaphragm pump won’t start up in the line startup cycle. The line air pressure has to be cranked all the way up to get it jump-started.”
2. Check on the pump maintenance and repair history, i.e, work order history, pump-shop work performed, parts purchased/used. Here’s what we found:
a. Work order subject: “Diaphragm pump repair”
b. Pump shop work orders: “Rebuilt the pump. Put on new check balls and seals.”
c. Parts purchased/used: “Pump rebuild kit (check balls and seals)”
3. Check the pump OEM documents for “Pump Maintenance.” We found the following three procedures:
a. Pump check balls & seals replacement
b. Diaphragm replacement
c. Air motor rebuild
4. Verify pump parts purchased in the past 12 months:
a. Pump rebuild kit includes check balls & seals: “Three kits ordered”
b. Air motor rebuild kits: “No kits ordered”
5. Symptoms observed:
a. After the pump was started by cranking up the pressure it operates as designed. So, the diaphragms, check balls and seals appear to be working properly.
b. Check the startup air-pressure setting and the control functions. They were set at the proper pressures.
c. “Diaphragm pump won’t start up in the line startup cycle. The line air pressure has to be cranked all the way up to get it started” indicates a potential problem with the air motor that drives the pump diaphragms.
6. Potential cause of the diaphragm pump problems: “Air motor not operating properly.”
7. Solution to try: “Order an air motor rebuild kit and rebuild the air motor.”
8. Did this action solve the problem (Yes/No)? “YES, the pump started normally with process startup.” If “NO,” consider the possibility that the pump-personnel (maintenance) did NOT:
a. Troubleshoot the pump problem, and/or
b. Did not understand how the pump works, especially the function of the air motor (since an air-motor repair kit was not purchased).
ELIMINATE THE PROBLEM
When this troubleshooting/problem-solving scenario was reviewed with the maintenance supervisor, it was discovered that the new maintenance personnel who were routinely sent to fix the pump had never considered the air motor in the diaphragm pump.
At this point, An Action Plan was developed. It included a review of the OEM pump maintenance procedures, a bench examination of a spare pump, stocking- spare diaphragms, pump-rebuild kits, and air-motor rebuild kits, then communicating how the problem was solved to both operations and maintenance.
THE TAKEAWAY
Making a production process reliable depends on eliminating the problems with the weak links, the chronic failures, the most penalizing problems first. This new reliability-improvement process is now working in the plant. Furthermore, the story is being shared as a best-practice in troubleshooting, problem solving, and problem elimination. It has become a foundation building block for a reliability improvement work culture in one key manufacturing process.
The goal is to keep adding building blocks to the reliability improvement work culture foundation.TRR
ABOUT THE AUTHOR
Bob Williamson is a long-time contributor to the people-side of the world-class-maintenance and manufacturing body of knowledge across dozens of industry types. His background in maintenance, machine and tool design, and teaching has positioned his work with over 500 companies and plants, facilities, and equipment-oriented organizations. Contact him directly at 512-800-6031 or b[email protected].
