Lean
Think of a maintenance department as serving internal customers: the various departments and workers in the company.
Lean is different from the traditional western, mass production model that relies on economies of scale to create profits. The more you make the cheaper the product will become, the greater the potential profit margin. It is based on predictions of customer needs, or creating customer needs. It has difficulty dealing with unusual changes in demand.
Lean production responds to proven customer demand. Pull processing – the customer pulls production. In a mass system the producer pushes product onto the market, push processing.
Lean requires:
building a long-term culture that focuses on continuous improvement
respect for workers and improving their training
Lean is a philosophy that focuses:
on meeting customer needs
on continuous, gradual improvement
on making continuously better products
on valuing the input of workers
on taking the long term view
on eliminating mistakes
on eliminating waste
Waste = using too many resources (materials, time, energy, space, money, human resources, poor instructions)
Waste:
overproduction
defects
unnecessary processing
waiting (wasting time)
wasting human time and talent
too many steps or moving around
excessive transportation
excessive inventory.
Lean production includes working with suppliers, sub contractors, and sellers to streamline the whole production process. The goal is that production would flow smoothly avoiding costly starts and stops.
Just in time “produce only what is needed, when it is needed, and only in the quantity needed.” Production process must be flexible and respond quickly.
Lean inventory = just what you need where you need it
In mass production = just in case inventory. Extra supplies and products are stored just in case they are needed.
RESOURCES
The philosophy of Lean Production
http://www.sitemaker.gr/silamianos/assets/confpaper.pdf
check on Wikipedia
Lean Principles Applied to CMM (article)
Running a CMM system is a good place to implement lean practices.
5 S
Seiri (Sorting) Getting rid of anything that is not necessary, store or discard
Seiton (Straighten) – workplace arranged for efficiency, clean orderly, limit movement or effort required to locate parts and then transport parts.
Seiso (Shine) – keep the place clean and neat so that the visual cues of problems can be noted right away, daily activity
Seiketsu (Standardize) – operations - what is to be done and who will do it, measurement of quality work, make sure everyone knows the standards.
Hitsuke (Sustain) - discipline of working to standards, understand and obey, eliminate unproductive habits, work to improve.
workers must want to work this way
uses workplace organization to improve production
therefore discipline & commitment are required.
Costs are lowered in a lean system by eliminating waste including “non-value added activities”
Muda – Waste
Overproduction = doing too much
Transportation – movement of people, materials, information = job planning
Waiting – for parts or decisions or other work to be done (wrench time versus think time)
Inventory – only stock the parts or materials and supplies you need – material supply process
Motion – the doing of a task
Process simplification = a process outside of the flow of production
Defects – the mass production system does inspection at the end of production to catch defects before they are shipped. The problem is that the resources have already been “spent” to make the waste product” Try to prevent problems immediately, as they happen, then prevent them from recurring. Inspections occur during production, at each stage of production and workers are empowered to stop production to repair problems.
Safety prevents waste of human resources
Information – need the right information at the right time (not too much, not too little, not too late)
Principles
Pull processing – (demand drives the work) in maintenance the demand is no (or very few) breakdowns and no defects
Design and plan for quality
Eliminate waste
Continuous improvement
Flexibility
Long term relationships
Poka-yoke –mistake proof determining the cause of problems and then removing the cause to prevent further errors (root cause analysis)
Judgment errors – finding problems after the process
Informative inspections –analyzing data from inspections during the process
Source inspections – inspection before the process begins to prevent errors.
Kaizen = continuous improvement is both a philosophy and a formal process with kaizen meetings to solve problems
MEAN LEAN
One of the terms applied to just cost cutting, job cutting interpretation of Lean is Mean Lean. Often modern managers think they are doing lean without understanding the importance of workers and long term relationships. They do the cutting without understanding the philosophy.
Reliability Centered Maintenance
another philosophy of maintenance
Reliablity centered maintenance is a system for designing a cost effective maintenance program. It can be a detailed complex, computer, statistically driven, but at its basics it is fairly simple. Its ideas can be applied to designing and operating a PM system, and can also guide your learning as you do maintenance, troubleshooting, repair and energy work.
These are core principles of RCM. These nine fundamental concepts are:
• Failures happen.
• Not all failures have the same probability
• Not all failures have the same consequences
• Simple components wear out, complex systems break down
• Good maintenance provides required functionality for lowest practicable cost
• Maintenance can only achieve inherent design reliability of the equipment
• Unnecessary maintenance takes resources away from necessary maintenance
• Good maintenance programs undergo continuous improvement.
Maintenance consists of all actions taken to ensure that components, equipment, and systems provide their intended functions when required.
An RCM system is based on answering the following questions:
1. What are the functions and desired standards of performance of the equipment?
2. In what ways can it fail to fulfil its functions? (Which are the most likely failures? How likely is each type of failure? Will the failures be obvious? Can it be a partial failure?)
3. What causes each failure?
4. What happens when each failure occurs? (What is the risk, danger etc.?)
5. In what way does each failure matter? What are the consequences of a full or partial failure?
6. What can be done to predict or prevent each failure? What will it cost to predict or prevent each failure?
7. What should be done if a suitable proactive task cannot be found (default actions) (no task might be available, or it might be too costly for the risk)?
Equipment is studied in the context of where when and how it is being used
All maintenance actions can be classified into one of the following categories:
• Corrective Maintenance – Restore lost or degraded function
• Preventive Maintenance – Minimizes opportunity for function to fail
• Alterative Maintenance – Eliminate unsatisfactory condition by changing system design or use
Within the category of preventive maintenance all tasks accomplished can be described as belonging to one of five (5) major task types:
• Condition Directed – Renew life based on measured condition compared to a standard
• Time Directed – Renew life regardless of condition
• Failure Finding – Determine whether failure has occurred
• Servicing – Add/replenish consumables
• Lubrication – Oil, grease or otherwise lubricate
We do maintenance because we believe that hardware reliability
degrades with age, but that we can do something to restore or
maintain the original reliability that pays for itself.
RCM is reliability-centered. Its objective is to maintain the inherent reliability of the system or equipment design, recognizing that changes in inherent reliability may be achieved only through design changes. We must understand that the equipment or system must be studied in the situation in which it is working.
Potential resources
A web resource for RCM
http://www.reliabilityweb.com/
An article I found helpful
http://www.reliabilityweb.com/art08/7_questions_rcm.htm
Source: http://cf.linnbenton.edu/eit/mec/greend/upload/Lean%20Manufacturing.doc
Web site to visit: http://cf.linnbenton.edu
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