What is Preventive Maintenance and How it works with SAP

This article gives you understanding of Preventive Maintenance processing with SAP Plant Maintenance. In Part 2, I will provide step by step guide for each of the items provided in this article.

What is Preventive Maintenance? 

Preventative maintenance (or PM) is the systematic servicing of equipment to reduce the possibility of failure and downtime. It improves upon your ROI and helps in maximum productivity in turn delivering business growth.
 

Why Preventive Maintenance is required & how is it helpful?

• To have standard check lists with operations to check the health of the machine periodically and optimize the maintenance schedules based on the results.
• To plan advanced procurement of components and provision of service for any technical object in a fixed interval.
• To carry out regular interval based maintenance on the technical object on a fixed frequency.
• Budgeting of resources: both material and human.
• To perform tasks to maintain the target condition and to determine the condition of a technical system.
• Mass planning of Preventative maintenance of all the equipment in a section / area.
• Maintenance activities carried out at a fixed frequency, can be planned and scheduled using this functionality.
• To identify a need of a corrective maintenance to replace a particular part of Main machinery in order to avoid any possible breakdown

Master Data required for Preventive Maintenance execution in SAP: 

• Functional Location
• Equipment
• Work Center
• Catalogs
• Maintenance Task list
• Service master (for external service procurement)
   

Preventive Maintenance’s components:

1) Maintenance Strategy (Transaction – IP11) :

It defines the criteria/rules for the sequence of planned maintenance work. It contains general scheduling information, and can therefore be assigned to as many maintenance task lists (PM task lists) and maintenance plans as required. A maintenance strategy contains maintenance packages in which the following information is defined:

• The cycle in which the individual work should be performed. For instance, every 100 operating hours, every three months, etc.)
• Extra data which could affect scheduling

What are the benefits?

• It reduces the time you need to create a maintenance:

You do not need to create the same scheduling information for each maintenance plan as it automatically gets fetched when you assign a strategy to a plan during creation.

• Update scheduling information easily and quick

When you make changes in the maintenance strategy (e.g, delete packages, change the preliminary or follow-up buffer), the changes are also valid for the assigned maintenance plans (they are referenced). However, the scheduling parameters are copied into the respective maintenance plan.
 

2) Maintenance Items (Transaction – IP04) : 

A maintenance item describes which tasks should take place regularly at a technical object or a group of technical objects. Of course, you can assign as many maintenance items as you want to a maintenance plan. But it will always automatically contains at least one item. Service procurement’s maintenance plans and those plans, which refer to an outline agreement have only one item.

Key ideas about maintenance items:

• An item can only be assigned to one plan.
• You must have created the maintenance item you want to assign to a single cycle plan or multiple counter plans without reference to a maintenance strategy.
• The maintenance item you assign to a strategy plan must have the same maintenance strategy as the maintenance plan.

How can you assign maintenance items to a plan?

• Create a maintenance plan and then create a maintenance item directly in that plan by entering the required data in the tab strip Item.
• Create additional items in a maintenance plan.
• Create a maintenance item without assignment and subsequently assign it to a maintenance plan

3) Maintenance Plans (IP01/IP41/IP42):

Maintenance plans describe the dates and scope of the tasks. You can create maintenance plans for the technical objects in your company, thereby ensuring that your technical objects function optimally. You will create a maintenance plan for both funcional locations and equipment.

Information included in a maintenance plan:

1.     Maintenance Item (Functional location/Equipment)
2.     Scheduling information
   1. maintenance cycle
   2. maintenance strategy ( Packages sequence)
   3. maintenance cycles sets in case of multiple counter plans
   4. Call Horizon, Start of cycle, Shift factors etc.

Types of maintenance plans

1) Time-Based Maintenance Plan

Maintenance is performed in specific cycles for time-based maintenance planning (every X months). To represent simple maintenance cycles, you can create a single cycle plan. To represent complex maintenance cycles, you can create a strategy plan based on a time-based maintenance strategy.
 

2) Performance-Based Maintenance Plan

With performance-based maintenance plans, you can plan regular maintenance based on counter readings maintained for measuring points at pieces of equipment and functional locations. To represent simple maintenance cycles, you can create a single cycle plan. To represent complex maintenance cycles, you can create a strategy plan based on a performance based maintenance strategy.

Assign a counter to the maintenance plan. Maintenance takes place when the counter for the technical object has reached a certain reading, for example, every 100 operating hours, every 100 molding cycles. The calculated planned date depends on the counter reading at the time of planning, and the estimated annual performance that has been defined for the counter.

Maintenance Plans Classification 

• Single Cycle Plans:

A single cycle plan is the simplest form of maintenance plan. You create a single cycle plan and define exactly a time-based or performance-based maintenance cycle, in which you specify the interval at which the maintenance plan should be executed. It can be time based & performance based both.

• Strategy Cycle Plans:

We create a strategy plan and assign a maintenance strategy in which you have defined the maintenance cycles (in the strategy maintenance packages). A maintenance strategy contains general scheduling information and can therefore be assigned to as many maintenance plans and maintenance task lists as required. For Example: A maintenance task is performed on a reference object after every 1000, 2000 & 5000 operating hours

• Multiple Counter Plans:

Multiple counter plans are used in counter-based (performance-based) maintenance. This type of maintenance planning is not based on a maintenance strategy. This means that you create a multiple counter plan without a maintenance strategy.

In the multiple counter plan you create maintenance cycles and allocate counters of equipment or functional locations with different dimensions to them, for example, flight hours, number of takeoffs and landings, kilometers traveled. You can also integrate time-based cycles into the maintenance plan. However, these do not have counters. Alternatively, you can also create a multiple counter plan with a cycle set as a copy model for maintenance cycles.
 

Maintenance Plans Category

Maintenance plan categories are possible based on call object generated by a maintenance plan:
                       1) Maintenance Order
                       2) Maintenance Notification
                       3) Service Entry sheets
 

Maintenance Plans scheduling (Transaction – IP10) :

We schedule a maintenance plan with which the system generates maintenance Notification/Order for the defined cycles.  For each scheduling, the system calculates the due date (planned date) for a maintenance call object based on the scheduling parameters and the defined frequency like weekly, monthly, quarterly, yearly etc and generates maintenance calls. These maintenance calls can be fixed or skipped as per requirement. If the call object is selected as notification, then the maintenance order of required type can be created through the notification screen.

Deadline Monitoring (Transaction IP30) : 

This function will simplify the generation of maintenance call objects for plans. Start the deadline monitoring at regular intervals using an internally programmed report. The system then generates the maintenance call objects according to the cycles defined. A start date or an initial counter reading must have been entered in the scheduling parameters for the maintenance plan, or you must have already scheduled the maintenance plan once.

When you run the deadline monitoring function, the system converts all the maintenance calls, for which the call horizon has been reached, into maintenance call objects. The system also performs a complete rescheduling of the maintenance plan and ensures that maintenance calls are always available for the period which you have defined as the scheduling period.