How efficient is your preventive maintenance program? The reality is that the typical preventive maintenance program achieves a staggeringly low 25-30% efficiency in labor hours. Where do the other hours go?
SEAM Group utilizes techniques based on Lean principles to identify waste in the PM work process. Over the next few weeks, this blog series will identify each type of waste to target for elimination to achieve efficiency in the PM process.
7 Wastes of Preventive Maintenance:
Producing more than the customer needs
The first part of the seven wastes is overproduction. Waste results from producing more than is required at any given moment by the next workstation or the final customer. Typical examples are; producing products to the stock based on sales forecasts, producing more parts to avoid lost time due to long set-ups, and batch process resulting in extra output in case of breakdowns.
Over-Production Waste in PMs:
- Redundant activities resulting from disconnected systems and/or work orders
- Tasks that cost more than the value provided. An example would be OEM manuals that are well-intentioned but without justification
- Over PM on non-critical equipment, specified by PMs copied from like type critical equipment or OEM manuals
- Performing PM tasks more often than needed
- Repairing non-urgent items found during a PM when the repair is not immediately required.
2. Movement of product that does not add value
Any time a product is moved, there is a risk of the product being damaged, lost, unavailable for further processing, or quality degradation. It is also an additional cost in labor, storage, and equipment that adds no value to the product and is something that a customer would not be willing to pay for.
Transportation Waste in PMs:
- Excessive travel between PMs through not using route functionality and poor scheduling.
- Excessive travel within a PM because the Craft does not have what’s required to complete the PM.
3. Movement of people that does not add value
The motion refers to the producer, worker, or equipment making the product. Excessive motion results in waste through unneeded reaching, sorting through materials, lifting boxes of parts, or walking. Consequences of this type of motion include safety issues and potential damage to products and equipment. Spaghetti diagrams can be used to help identify this waste.
Motion Waste in PMs:
- Performing PM tasks that can be designed out. Poor equipment design, and lack of RCFA.
- Excessive craft movement around the machine. Poorly organized PM tasking order within the work order.
- Excessive guard removal or accessibility. Poor equipment design.
4. Idle time created when material, information, people, or equipment is not ready
Whenever goods or products are not being moved or processed, the time spent waiting is easily identified as waste. Typically a significant percentage of a product’s manufacturing time is spent waiting to be processed.
Waiting for inspections, parts, prints, information, or machine repair can add hours to the production cycle and is regarded as a loss to the entire plant output.
Waiting Waste in PMs:
PM tasks waiting for equipment to be down that could be done while running. Centralized PM execution (all at once)
Waiting on equipment access. PM’s where maintenance schedules and production schedules do not match.
Waiting for parts on discovered defects during the PM. Poor planning, lack of repair decision matrix.
5. Effort that adds no value from the customer’s viewpoint
Waste in processing occurs either when more work is done on a product than is needed to finish it, or when tools and equipment are used in the production process that is more precise, expensive, or complex than are required.
Some examples of over-processing might include using expensive legacy equipment where less complex equipment could be used, over-tight tolerances, multiple cleaning of parts, excessive paperwork, and awkward tool or part design. Processing waste is sometimes described as using a sledgehammer to crack a peanut.
Processing Waste in PMs:
PM Tasks performed by inappropriate or higher skill set than necessary. Policy, training, poor task instructions, subjective criteria, equipment design
Excessive PM task time resulting from poor equipment design
PM tasks performed and failures still occurring. Lack of “PM task to failure” analysis
Excessive paperwork of work orders. Technology limitations, Crafts not using PC
6. More materials, parts, or products on hand than the customer needs right now
This sixth waste can be physically and visually identified. (See our previous blog posts for the first five of the seven Wastes: Over-Production, Transportation, Motion, Waiting, and Processing.)
Inventory in the form of raw materials, unfinished products or parts, or finished goods sitting on a pallet is non-income producing capital outlays. These build-ups can also be indicators of production problems and will uncover hidden constraints in the manufacturing process. Common causes of inventory build-ups include raw materials being stockpiled to compensate for supplier lead times, a lack of flow for work in process, long set-ups for finished goods, excessive lead times for consumable supplies, and paperwork delays for purchased components.
Inventory Waste in PMs:
Carrying too many PM-related spare parts. Pulling PM parts from stock instead of ordering them as needed, wrong PM task type.
Carrying too many Repair related spare parts. Repairing discovery when found.
Non-applicable PM tasks. Generic PMs, OEM manuals, CMMS limitations
PM that cannot foresee or prevent problems. Reactionary PM addition because of an unpleasant event.
7. Work that contains errors, rework, mistakes, or lacks something necessary
The last of the 7 Wastes is the one that is most frequently targeted, often to the exclusion of the other six. (Over-Production, Transportation, Motion, Waiting, Processing, and Inventory.
Defects are often a significant percentage of total manufacturing costs and reducing this waste is a major focus of many cost reduction or improvement initiatives. When defects occur, they can create issues in addition to the material cost by requiring re-inspections, rescheduling, and capacity loss. Waste through defects can be from scrap through process failure, reworks from misloaded parts, field failures in equipment, missing parts, variation, or batch process defects.
Defects of Waste in PMs:
- Inferior or inappropriate PM task. Training or systems limitations
- PM Tasks are performed incorrectly or take longer due to vague information. The assumption that people should know what to do, a poor planning function.
- Equipment failures where no PM strategy exists. Poor PM Development process, OEM manuals, and new equipment.
In summary, the categories used to define the 7 Wastes in Production are directly applicable to optimizing SEAM Group strategies. The use of these categories will help identify the wastes in your maintenance processes and permit either immediate removal of the waste or implementation of cultural changes that will give you long-term improvement in your PM program.
When done in isolation, PM Optimization (waste removal) yields tremendous impacts on craft labor, as well as increased reliability by doing the “right” PM. But when done as part of a Lean maintenance management system, can double the amount of work that an existing team can accomplish.