Preventive Maintenance

What is Preventive Maintenance?

Preventive Maintenance, also known as Preventative Maintenance, is an activity performed on the equipment to reduce the risk of failure. It proactively identifies potential failure points, replacing the worn out spare parts and carrying out general servicing, all of which is to impact the equipment functioning positively.

Preventive maintenance is also referred to as  Planned Maintenance, Scheduled Maintenance and  Preventative Maintenance.

How is Preventive Maintenance different from Breakdown Maintenance?

Breakdown Maintenance or Reactive Maintenance refers to carrying out maintenance activities after the equipment failure.  It’s primarily a break-fix activity executed to repair the failed equipment and bring it back to the working condition.  There is no planning or proactive approach involved, and breakdown maintenance is carried out as a reaction to equipment failure.

Preventive Maintenance is a planned maintenance activity carried out proactively, while the equipment is still in a running condition.  It is executed to avoid potential failures and costly downtime.   Equipment breakdowns are costly, resulting in wasted working hours, suboptimal use of associated equipment and missed opportunity costs. Therefore the primary goal of preventive maintenance is to avoid such equipment breakdown before it occurs.

Benefits of Preventive Maintenance

  • Improves equipment reliability resulting in higher production and product quality
  • Increases equipment life due to fewer failures and prevention of excessive damage
  • Keeps equipment in good condition increasing resource utilization and efficiency
  • Reduces unplanned downtime by resolving problems when they are tiny
  • Ensures other upstream and downstream equipment on the assembly lines utilized to their full potential
  • Increases productivity, avoids repetitive failures and optimizes labor and operational costs.
  • Institutionalize the process thereby ensuring repeatability and consistency
  • Increases the overall safety of the equipment

What are the different types of Preventive Maintenance?

Different types of Preventive Maintenance include

a.    Time Based Maintenance 

Time Based Maintenance (TBM) wherein, the preventive maintenance activities recur periodically, based on a specific calendar schedule. Weekly, Monthly, Quarterly, Annual, Bi-annual scheduled maintenance are examples of TBM.  Time based maintenance is generally a planned maintenance program and is based on elapsed time.  Time based preventive maintenance  recurs over fixed intervals, regardless of their usage or performance, in that period. 

A variant of time based preventive maintenance is floating schedules, wherein the successive maintenance schedule occurrence will depend on the previous completion.  Floating schedules require the earlier scheduled  maintenance activity to be complete and the specified time interval has elapsed.   

With fixed interval preventive maintenance schedules, successive work orders will get generated irrespective of the status of the prior work orders. Floating preventive maintenance schedules avoid unnecessary queueing up of redundant preventative work orders, by imposing an extra condition of prior work order closure.

 

 

b.   Usage Based Maintenance

Usage Based Maintenance (UBM) wherein preventive maintenance schedules are based on the equipment usage, rather than elapsed time.  Thus, Usage based maintenance avoids redundant preventative maintenance activities on unused equipment.  Usage based maintenance may recur based on run hours or cumulative production units etc.

Usage based requires a metering mechanism to track the parameter that trigger the preventive maintenance schedule.  Such metering mechanism may be automated and captured directly from the machine interface or manually done via log books.   Every time the preventative maintenance work order is generated, the meter is reset or the system is configured to increment the metering interval for calculating the new threshold.   

Usage based maintenance is not dependent on mere calendar and thus an advanced preventive maintenance program, that takes into account the actual usage of the equipment.   Usage based preventative maintenance can occur at different intervals of time, based on equipment usage.

 

c.    Condition Based Maintenance

Condition Based Maintenance (CBM) wherein preventive maintenance work orders are generated when certain critical parameters breach the specified threshold or control limit. 

In Condition based maintenance, the normal operating range for the critical parameters are configured in the system as a business rule. Meter readings of the critical parameters at regular intervals are compared against these business rules.  Any discrepancies in  critical parameters is treated as a symptom of malfunction and a  preventative work order is generated with that issue code.

Condition based maintenance gives alerts on the first occurrence of the symptoms and thus avoids costly breakdowns.   They provide sufficient time for the maintenance team to prepare, respond and repair before the equipment failure.

Condition based maintenance requires robust operational technology systems like PLC, SCADA, MES, Internet of Things etc. that continuously monitor the equipment performance parameters and report to the CMMS Software.

 

d.   Event Based Maintenance

Event Based Maintenance (EBM) occurs upon the incidence of a certain events like annual fire drill, customer visit etc.  A set of scheduled work orders will be generated upon the occurrence of the event.   Unlike time based maintenance that occurs on a specific schedule, usage or condition based maintenance that occurs based on certain parameters,  Event based Maintenance is dependent on external events.  

 

How do you administer a Preventive Maintenance Program?

Preventive Maintenance is a crucial part of any business activity since its principal objective is to preserve the availability of the assets that can use for the business. Preventive Maintenance program follows the Enterprise Maintenance Plan and adheres to the goals and objectives laid out in that.

1. Preventive Maintenance Planning (Preventative Maintenance Planning)

Efficient preventive maintenance requires careful planning and preparation. Based on the asset hierarchy, equipment grouping and usage conditions, detailed plans including maintenance task checklists, spare parts replacement, and tools required for supporting the maintenance activity described. Checklists and spare parts replacement schedule are drawn using a combination of manufacturer’s specifications, operating knowledge and past learnings.

The principal deliverable is to design a preventive maintenance procedure that is comprehensive, adequately, repeatable, clearly specified granular tasks with estimated duration and optimal recurrence frequency of preventive maintenance.

2. Preventive Maintenance Scheduling (Preventative Maintenance Scheduling)

Scheduling is a long-range planning activity and includes the recurrence pattern or conditions that trigger the preventive maintenance.  Scheduling involves defining the business rules that trigger the Preventive Maintenance Work Order to be generated.   It’s based on a combination of different types of Preventive Maintenance like Time Based Maintenance, Usage Based Maintenance, Condition Based Maintenance, Event Based Maintenance etc.  

 

CMMS helps in creating Effective Preventive Maintenance Programs

3. Planning & Administration

Administration of preventive maintenance is based on prevailing on-ground situations, including equipment and resource availability. It includes  prioritization of PM tasks,  adjusting and fine tuning individual equipment schedules based on their availability, resource levelling to distribute uniform workload and scheduling the activities in such a way it causes least disturbance to production(eg. holidays, third shift etc.) and communicating to all stakeholders.  

4. Execution. 

Preventive maintenance execution consists of multiple tasks, often involving cross-functional teams, and has performed in a specified sequence. For efficient utilization of time and quicker turnaround, adherence to preparatory activities listed in the plan is a must. Includes collecting the spare parts specified, booking of standard tools and securing necessary work permits.

Efficient execution requires following the laid out task plan and also ensuring conformance to duration and timeliness. Abnormalities observed, if any, should be reported back for proper analysis and remediation. Adequate handover upon completion and documentation of completion status and spares consumption has followed.

5. Continuous Improvement:

Ongoing improvements to the processes, operational tasks, schedules, etc., based on the learnings from the history and industry best practices help to institutionalize the knowledge and standards and to roll out a world-class preventive maintenance program. Includes definition and tracking of metrics,  identifying opportunities for streamlining the practices, eliminating waste and deploying horizontally.

Horizontal Deployment is the process of sharing the learnings and best practices laterally across the organization. In preventive maintenance context, the improvements made for specific equipment, to avoid a potential breakdown can be copied over to all the other stuff belonging to the same class of material. Propagates peer-level learning and avoids expensive failures.

 

What is a Preventive Maintenance schedule?  

 

Preventive Maintenance schedules (PM schedules) are defining the trigger conditions that will generate a preventive maintenance work order for a specific asset.  PM Schedules will follow a set pattern  like weekly on Monday, Wednesday  and Friday, 5th of every month or last Sunday of every third month etc. or 365 days since completion of last work order generated by the same parent schedule or for every 3,000 equipment run hours.   In addition to these trigger conditions, PM schedules will also contain the specific asset details, the list of jobs that need to be completed, sequencing of steps, if any, assignment details like individual or group who will execute the job. 

 

PM Schedules may also contain the spares that needs to be changed, maintenance and safety instructions, work permits to be procured, common tools required (eg. Cranes, forklifts etc.), vendor coordinate required, if any and shift in which it needs to be carried out.  PM Schedules are configured as a parent schedule with all the details and when the trigger conditions are met, PM work orders are created by the system automatically with all underlying details and assign it to the relevant person or group.

 

 

What is a Preventive Maintenance task list?

 

Preventive Maintenance task lists (PM task lists), sometimes referred as PM Checklists, PM Sheets or Job Plans are the list of tasks that needs to be executed and the inspections to be carried out,  to complete the Preventive Maintenance.   PM Task lists will define who (assignment), what (task name), when (sequence, if any), how (task details and spares to be replaced) etc. 

 

How do you measure the Preventive Maintenance programs?

Key Metrics that are used to measure the Preventive Maintenance programs are

1.     PM Compliance:

Preventive Maintenance Compliance (PM Compliance or PMC or Schedule Compliance) is the rate of completion of Preventive Maintenance schedules.   It is measured as the number of preventive maintenance activities completed to total number scheduled in a given period of time and is expressed as a percentage.

2.    PM Effectiveness:

Effectiveness is the capability of producing a desired result or the ability to produce desired output.  Thus Preventive Maintenance to be effective it has to meet the intended business outcome of preventing breakdowns.   Preventive Maintenance Effectiveness (PM Effectiveness or PME) is an indicator on the degree of success or its likelihood in achieving desired result.

What is Shutdown Maintenance?

Process industries run continuously and thus isolated preventive maintenance without impacting the more extensive operations is difficult. Planned maintenance for such sectors involves a shutdown of the entire services to facilitate the preventive maintenance activities.

The scale of operations, complexities and interdependencies demand a great deal of planning to determine what needs to be shut down and in what sequence, and what must be done during the shutdown, what may be done to restart the plant and resume operations, including contingency plans, and what can be done after the restart.

Shutdown maintenance is done once in a few years and preparation and planning draws extensively from history, statistical techniques, risk analysis, project management and coordination.

Future of Preventive Maintenance

Preventive maintenance programs started with simple planning exercises with wall charts and card indexes. Visual schematics, project plans, process diagrams and color codifications aid in simplification of preventative maintenance planning and execution. History cards, job control, safety and sustainability procedures and past learnings were used to improve effectiveness. Larger plants went for Computerized Maintenance Management Systems (CMMS) to streamline the various equipment that they manage.

While early CMMS tend to focus more on preventative maintenance scheduling, resource management and inventory, advancements in technology brought in many more conditional monitoring capabilities inbuilt in CMMS. Technological advances in real-time data capture, large-scale and cost-effective storage systems and analytics enabled quicker adoption of condition-based maintenance across industries. Simultaneously the significant shifts in the cloud, analytics, and mobile CMMS technologies made such sophisticated CMMS available for even small and medium organizations at affordable costs.

Evolution and maturity of Plant Maintenance practices
 Breakdown MaintenancePreventive Maintenance
Predictive Maintenance
FocusFix failures after they occurAvoid failures Forecast failures
Control
Triggers Equipment breakdownRun hours
Elapsed calendar time
Breach of critical
parameters
Statistical analysis
Trend deterioration
Actions arising out of
predictive algorithms &
sophisticated
equipment modeling
EnablersTroubleshooting
Maintenance support
Maintenance checklists Condition Monitoring
SCADA, Internet of Things
Maintenance
Behaviour
Run to failure
Reactive
Organized and SystematicOptimized and Futuristic

Condition monitoring has become ubiquitous today with most equipment manufacturers providing data access to critical parameters. CMMS integration with sensors, programmable logic controllers (PLCs), SCADA, smart devices and other automated sources of data capture is leading to a data explosion. Humongous data inundation has shifted the focus of tools from consumption to management by exception and action-oriented insights.

Real-time data availability simultaneously from multiple types of equipment has led to the modeling of systems behavior more accurately. Powerful algorithms and system modeling is redefining modern shop floor and leading to a holistic understanding of equipment, operating conditions and helps us predict their failures. Preventive maintenance today is transforming itself into predictive maintenance.

Why is MaintWiz CMMS an ideal solution for managing your Preventive Maintenance programs?

MaintWiz is a new age platform that helps you to digitize your maintenance operations and assist you with powerful tools to manage Predictive, Preventive and Breakdown Maintenance programs. MaintWiz is a Simple, Easy to use, Integrated, Cost effective and Scalable solution.

Key benefits of MaintWiz in designing and administering Preventive Maintenance plan include:

1.  Robust feature set to manage the entire preventive maintenance program, including scheduling, checklists, spare parts, tools management, resource management and tracking.
2. Comprehensive scheduling capabilities to match the unique needs of every industry. Support time-based maintenance (fixed and floating), condition based maintenance and event-based maintenance.
3. Sophisticated functionalities under the hood are simplified for the user, with easy to use excel uploads. Excel uploads support schedule setup, task lists design and spare parts recommendations. Copy paste functionality to copy assignments over from past work orders is also available.
4. Planning Workbench: Adjusting the preventive maintenance work orders generated out of the long-range scheduling to meet short-term, tactical on-ground realities without impacting the master schedules. You can optimize the plan based on equipment availability, resource leveling, spare parts and tools availability
5. One-click maintenance to help maintenance team complete their preventive maintenance tasks at the point of work, via a mobile app.
6. State of the art analytics and interactive reports to monitor preventive maintenance compliance, cost of preventive maintenance, horizontal deployments and more.

With MaintWiz there are no entry or exit costs. It’s offered on a monthly subscription basis. Excel templates based data upload enables you to start quickly on Day 1. Experience the complete power with Zero Capital Investments and Zero Implementation Time.

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