Plant Design for Reliability
A plant is not designed to produce defects
Retard deterioration. Detect defects, before they cause breakdowns.
Restore damaged components into proper condition, at minimum cost.
Plant Maintenance deals with defects and deterioration at your equipment. However, every defect must be avoided.
No computer program, no outsourcing, no benchmarking, no auditing eliminates one single defect!
A reduction of 40 – 75 % breakdowns within just the first year is possible!
Fighting defects at your manufacturing equipment
- “Servicing”, maintenance, mainly preventing -or retarding- deterioration through cleaning, lubricating, impregnating and conserving
- “Inspection”, checking condition or function of plant in order to identify deterioration or defects in time
- “Repair”, eliminating defects and putting plant back into a proper (not necessarily the initial) condition
The Effects of Maintenance Management
Reducing number of (unwanted) occurrences (what I call Preventive Maintenance)
- eliminating “weak components” (suffering from substandard defects occurring chronically)
- eliminating causes of defects occurring sporadically
- retarding deterioration through servicing
- systematically designing new plant resisting deterioration and easy to maintain (“Reliability” and “Maintainability”)
Optimization of the workload per maintenance activity
- pplying efficient technologies
- avoiding idling from poor organization
Minimizing indirect material cost for maintenance
- optimizing stock cost, mainly through avoiding uneconomical stocks of spares by using more economical alternatives to make parts and material available
- minimizing out-of-stock cost by putting adequate priorities
- optimizing issuing cost by un-bureaucratic means
- optimizing indirect purchasing cost
Where and how should you optimize your maintenance?
- You measure and assess quantitatively the output, how far you achieve the above maintenance effects.
- You acknowledge the fact, that the majority of all defects (and of all maintenance cost) occur, not because your plant just deteriorates but because the equipment components are being ruined through organizational failures.
- Just auditing your procedures (and not measuring their output) would not give you significant guidelines.
What many people mean when talking about “Preventive Maintenance”
Since many decades people are dreaming of this: After pre-determined periods all (or most) defects should be eliminated by replacing the components with new ones. This way they hope to carry out maintenance in well planned and controlled revisions (not in individual repairs, the moment of which had not been known much time in advance). As prototype they refer to airlines, (wrongly) claiming that these after a given period of time would strip down their aircrafts and replace the components irrespective of their actual condition.
We know since 1960 (the latest) that this procedure
- is in fact harmfully impairing the plant and process reliability, because it damages additional components that prior to this intervention had been intact,
- is uneconomical, because – due to the wide statistical spread if life time – not fully exploiting the actual potential component life but replacing most components long before their potential life has been elapsed
- is expensive because requiring frequent and long shut down times
Then we know since 1990 that only a minority of all defects (and the resulting breakdowns and malfunctions) occur at components, of which we could that predict, because they are short-life components or “weak components”.
If you spend more than 10% of your maintenance budget on periodic maintenance activities, you are wasting money!
The only cure is: Avoiding defects, don’t try to control them (you can’t)!