Case Study – Frequent maintenance in Stack Analyser (Banish MUDA)
This is a beautiful case study resembling positive approach of the team towards finding solution.
A stack analyser was having very high frequency of maintenance. Being mounted in stack of incineration plant, the probe was exposed to dust & acidic gases, which were the main cause of probe failure. Main Issues with the Analyser is:
- High Frequency of Cell and heater failure.
- Frequent chocking of cell assembly.
- High time required for cleaning and cell replacement.
- High cost of maintenance
The team took up the challenge to come out of the issue. The study done was a good example of usage of various reliability tools like RCA, Fishbone diagram, Brainstorming, etc. ,there is another angle to it, ie. Lean Management. The main objective of the study was to reduce the quantity of jobs performed on the analyser.
The team has recently gone through “7 Wastes-Mr. TIMWOOD “. They decided to identify the wastes in the activities on the analyser. All the activities were identified & written.
Each activity was studied and type wastes were identified.
Analysis of the identified waste is as under:
- Transportation of probe to the repair location: Can the probe be repaired at the installed location?
- Motion of the workmen for steaming, hammering & temporarily electrical connections: Why Steaming, Hammering is required? Why temporarily connections are required?
- Defect during leak checking: What is the procedure for ensuring correct assembly?
- Inventory: How to reduce inventory required supporting the frequent maintenance?
- Waiting: Why can’t the warm up done at location?
- Over Processing: Why calibration & response check is required two times?
The next step was to find answer to these questions. The maximum time was consumed by removal of Cell & seal assembly. RCA tool, Why Why analysis was used to drill down to accumulation of the acidic dust at the cell as the root cause. A ceramic diffuser was prepared with OEM, to put in place of mesh, which is more capable of filtering dust. This small change after value engineering has resulted in substantial improvement in terms of time, cost, inventory, maintenance frequency, reliability & availability of the instrument.
Cost of Modification: Rs. 25000
- Total time of job was reduced from 8.8 hours to 4.3 hours.
- No. of jobs reduced from 10/year to 4/year.
- Material cost reduced from Rs. 1.8 Lakh to Zero.
Experience of industries has been concentrated in different quality, Reliability & Lean tools. Correct knowledge & implementation of these tools is necessary for best results.
Check other case studies on Vanilla Ice Cream and Flight 5390 failure.
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Case Study- Frequent maintenance in Stack Analyser (Lean Tools)