Identification of waste in the maintenance process
L. (Tex) LeugnerFacilities Maintenance Machinery and Equipment Maintenance Preventative Maintenance condition monitoring equipment reliability improvement maintenance maintenance process predictive maintenance reliability waste
Industrial equipment design changes as technology changes. As a result, maintenance is not a function, but rather an ongoing dynamic process.
Company culture must be continually reviewed and developed to ensure that every employee remains part of the equipment reliability improvement process.
When continuously improving an equipment reliability program, two fundamental questions must be answered; what is effective maintenance, and what is efficient maintenance?
Effective maintenance means doing the right maintenance tasks at the right time, while efficient maintenance means carrying out each maintenance activity correctly so that rework is never necessary.
Many tools have been developed over the years to assist maintenance and operations professionals to help answer these questions, including predictive maintenance condition monitoring, reliability centered maintenance, the 6S program and equipment reliability improvement programs, utilizing Six Sigma statistical measurement.
However, simply put, most organizations could resolve many of their maintenance problems by recognizing and removing waste with the implementation of lean maintenance; a strategy that recognizes and removes eight forms of waste.
How does your organization deal with waste of maintenance overproduction?
LOGIC: Overproduction includes poorly prioritized or excessive preventive maintenance (PM). PM programs must be reviewed periodically to ensure that these activities are proven effective at reducing potential machine failures and production stoppages, and carried out efficiently.
How does your maintenance department eliminate the waste of waiting?
LOGIC: lost time waiting for parts, waiting for transportation to the site, waiting for equipment to be shutdown prior to work, waiting for planning and/or scheduling are only a few of the time wasters that maintenance technicians experience in many organizations.
How does your organization deal with the waste excessive travel?
LOGIC: many manufacturing and process facilities cover acres of property. Examples include energy producers and automotive plants. Waste includes technician’s travel to the job, spare parts, special tools or product delivery.
How does your organization deal with inappropriate or unnecessary processing in the maintenance group?
LOGIC: examples of this waste include excessive work order processing, missing work order information, poor or no planning, scheduling mistakes and utilizing planners or schedulers for activities unrelated to their specific responsibilities.
How does your organization deal with waste associated with inventories?
LOGIC: examples of this waste include poor (or no) control of tool cribs and spare parts stock rooms. Some organizations place special tool and spare parts control up to maintenance planners or the technicians themselves which are invitations to stock control disasters.
How does your maintenance group manage the waste associated with unnecessary motion?
LOGIC: this waste includes technicians looking for additional technical information, picking parts or supplies (not pre-packaged for pick up or delivery to the job site), and ordering and obtaining additional resources never included on work orders.
How does your organization manage the waste associated with knowledge and skill?
LOGIC: this waste includes under utilizing the knowledge of machine operators (who very often know more about certain machines and processes), than the technician and under-utilized skills or knowledge of the technicians themselves.
How does your organization manage the waste associated with defects, call-backs and repetitive failures?
LOGIC: these include poorly concluded or incomplete repairs due to production demand over-ride, poor or incomplete work order instruction detail, poor (or no) planning or scheduling, the frequent absence of proper failure analyses processes and procedures.
Eliminating the sources of waste described above can be done by developing processes and procedures that will help the maintenance organization provide effective and efficient service to the production or manufacturing group.
The process must focus on continuous machine reliability improvement, and begins with thorough and complete documentation of the specific critical equipment necessary for uninterrupted production in the facility. Next, preventive maintenance procedures and processes must be correctly and completely documented, including when and how maintenance activities are to be carried out.
This process should include monitoring the time required to carry out specific maintenance activities, including preventive, corrective and repair tasks. When and where appropriate, the application of condition monitoring tools, such as taking vibration measurements and obtaining oil samples, can be included as part of the preventive maintenance program, and technicians should be trained to carry out these tasks as part of their PM routes.
Whereas OEE (overall equipment effectiveness), measures loss in equipment, OME (overall maintenance effectiveness) on the other hand, measures losses (waste) within the maintenance processes and provides information on waste in the maintenance work backlog.
Scheduled PM, including necessary condition monitoring, can be generated according to a pre-established program often referred to as the “forecasted backlog.” Thus, PMs are removed from the planning and scheduling of the “ready backlog,” that includes corrective maintenance, specific improvement projects and jobs approved for carry over from a previous shift.
All of this work requires the full and complete attention of the maintenance planner/scheduler to ensure that all parts, supplies and any special tools are correctly and properly ordered and obtained just in time to conform to the schedule. When undertaking the repair work itself, the process of documentation continues including the work done, how much time was required and the inclusion of unexpected delays due to an absence of spares or tools resulting from the frequent discovery of more extensive damage to the machine on disassembly.
Finally, where a critical machine component or the machine itself has failed, analysis of all critical components or machine failures should be carried out in order to prevent re-occurrence.
Once all of these processes are well developed, it makes it much easier to continually improve upon the processes and procedures that can remove even more of the waste described, making it easier to make improvement adjustments, and these can be leveraged across the entire organization. Although most company’s maintenance programs are driven by preventive maintenance, condition monitoring, planning and scheduling and work order management, the identification, measurement improvement and ongoing analyses of labour hours expended efficiently and effectively is the key to reliability improvement. MRO
L. (Tex) Leugner, the author of Practical Handbook of Machinery Lubrication, is a 15-year veteran of the Royal Canadian Electrical Mechanical Engineers, where he served as a technical specialist. He was the founder and operations manager of Maintenance Technology International Inc. for 30 years. Tex holds an STLE lubricant specialist certification and is a millwright and heavy-duty mechanic. He can be reached at firstname.lastname@example.org.