Maintenance Strategy

[shirsendu_roy2]

I am trying to capture some information related to maintenance strategy in this blog post.

If we need to perform some maintenance tasks on a piece of equipment or a group of equipment or a system based on some predefined frequency (more than one frequency) we use a maintenance strategy. If the tasks have only one frequency we might not use a maintenance strategy.

Before creating a maintenance strategy we may need to analyze how the tasks have been defined by the reliability team. We can define a maintenance strategy as hierarchical or non-hierarchical or as a combination of both of them.

Let's consider a situation where the maintenance tasks for a Pump define as below

1M task - Greasing

2M task - Greasing + Seal inspection

3M task - Greasing + Seal inspection + Coupling inspection

6M task - Greasing + Seal inspection + Coupling inspection + Alignment

12M task - Greasing + Seal inspection + Coupling inspection + Alignment + Internal inspection

We could see in the higher frequency tasks, the lower frequency tasks are also included, so for the above situation we can use a hierarchical maintenance strategy, i.e. in the work order, we would see only one task which is the highest frequency task in the particular call.

Package

Cycle text

1 MON

2 MON

3 MON

4 MON

5 MON

6 MON

7 MON

8 MON

9 MON

10 MON

11 MON

12 MON

1

1 Monthly

1M

1M

1M

1M

2

2 Monthly

2M

2M

2M

2M

3

3 Monthly

3M

3M

4

6 Monthly

6M

5

12 Monthly

YR

Let's consider another situation where we need to use a non-hierarchical maintenance strategy, i.e. the higher frequency tasks do not include the lower frequency tasks like the below table

1M task - Greasing

2M task - Seal inspection

3M task - Coupling inspection

6M task - Alignment

12M task - Internal inspection

Package

Cycle text

1 MON

2 MON

3 MON

4 MON

5 MON

6 MON

7 MON

8 MON

9 MON

10 MON

11 MON

12 MON

1

1 Monthly

1M

1M

1M

1M

1M

1M

1M

1M

1M

1M

1M

1M

2

2 Monthly

2M

2M

2M

2M

2M

2M

3

3 Monthly

3M

3M

3M

3M

4

6 Monthly

6M

6M

5

12 Monthly

YR

To create a maintenance strategy we use TCODE IP11. Or through Fiori App "MAINTAIN MAINTENANCE STRATEGIES"

To create a new maintenance strategy we need to fill some mandatory fields and some non-mandatory fields.

1. Name ( Mandatory field) - To identify the maintenance strategy we need to provide the name.

2. Description ( Mandatory field) - we can use this field to identify whether it's a hierarchy or non-hierarchy-based maintenance strategy.

3. Scheduling indicator (Mandatory field ) - We have a total of four types of scheduling indicators. For a time-based maintenance strategy, we can use the following scheduling indicators, "Time", " Time - Key date" & " Time - factory caldr". For measuring counter (Like running hour) based maintenance strategy we will use scheduling indicator "Activity".(For the maintenance strategy with a Time-based scheduling indicator the call object's (work order or notification) planned date will be calculated based on the frequency.

PlanDate

04.02.2022

06.03.2022

05.04.2022

05.05.2022

04.06.2022

For the maintenance strategy with a Time- Key date-based scheduling indicator the call object's (work order or notification) planned date will be calculated based on the frequency but the planned date will be the same date.

PlanDate

04.02.2022

04.03.2022

04.04.2022

04.05.2022

04.06.2022

For the maintenance strategy with a Time- factory caldr-based scheduling indicator the call object's (work order or notification) planned date will be calculated based on the frequency but holidays will not be counted. So in between two 1 monthly call objects, there will be gaps for 30 working days, not 30 calendar days)

PlanDate

18.02.2022

01.03.2022

17.04.2022

28.05.2022

09.06.2022

4. Package sequence- Here we need to define different packages with their frequency.

To create a new maintenance package we need to fill some fields

4.1 Package no-  We need to define the Consecutive number of the maintenance packages. i.e. 1,2,3...

4.2 Cycle length- Here we can define the task frequency.

4.3 Unit- Here we need to define the Unit of the task frequency. i.e. Monthy, Weekly, etc.

4.4 Maintenance cycle text - we can enter a short description of the task frequency. i.e. 1 Monthly, 1 Weekly, etc.

4.5 Cycle short text - Here we can define the shot text of the task frequency.

4.6 Hierarchy - Here we can define the packages that will follow a hierarchical maintenance strategy

Hierarchy

1

2

3

4

5

or a non-hierarchical maintenance strategy.

Hierarchy

1

1

1

1

1

4.7 Hierarchy short text - Here we can define short text for the hierarchy.

4.8 Offset- Here we can define the offset of the package.

This offset is very helpful during migration activity like non SAP CMMS system to SAP or ECC ERP to S4 HANA migration.

Example- Suppose we have one 6 Monthly task in the legacy system and we have already performed the tasks two months ago. So if we want to migrate this task, and today we are going to schedule the maintenance plan through IP10, with the start date of today's date then the offset will be four months.

4.9 Offset short text - Here we can define short text for the hierarchy.

4.10 Initial (Lead float)- If we want to start the work before the planned date, then we can specify the number of days as a preliminary buffer here.

Example- If there is no lead float the basic start date will be the same as the planned date but if specify the lead float 2 days then the basic start date will be 2 days before the planned date.

4.11 Subsequent (Follow-up float) - If we want to finish the work after the planned date, then we can specify the number of days as a follow-up buffer here.

Note: For point numbers 4.10 and 4.11, the changes of the dates in the work order will depend on the customizing setting.

Customizing IMG path

SPRO>Plant Maintenance and Customer Service>Maintenance and Service Processing>Maintenance and Service Orders>Scheduling>Set Scheduling Parameters

or

We can use TCODE OPU7

To change the dates according to the lead and follow-up float we need to use the option "Do not adjust basic dates, dep. reqmts to operation dates" for "Adjust dates" in the "Adjust scheduling" section.

5. Strategy unit ( Mandatory field) - We need to define the strategy unit.

6. Call Horizon - If we need to get the call date before the planned date we can define that through call horizon. We can define call horizon by % or days ( Calendar days or factory calendar date).

Note - We can define the call horizon by days only in S4 HANA, not in ECC.

8. Shift factor for late compliance - If we want to change the next planned date based on the late completion of the previous call we can define here by how much percentage the next planned date should be shifted.

7. Tolerance for late compliance(%) - We can define the tolerance value here to define the limit when we do not want to change the next planned date if the last late completion date is within the tolerance limit.

9. Shift factor for early compliance - If we want to change the next planned date based on the early completion of the previous call we can define here by how much percentage the next planned date should be shifted.

10. Tolerance for early compliance(%) - We can define the tolerance value here to define the limit when we do not want to change the next planned date if the last early completion date is within the tolerance limit.

11. Factory calendar - We can define the factory calendar here.

12. Authorization Group - By assigning Authorization Group we can define the group that can use the maintenance strategy. If we left this field blank then anyone will be able to use the maintenance strategy.

13. Number of packages - We will be able to see the number of packages available in the maintenance strategy.

14. Usage - We can see the list of maintenance plans where the maintenance strategy has been used. We can get the same list by executing TCODE IP14 also.

Some other useful TCODEs

IP12 - To display maintenance strategy

IP11U - To reschedule the maintenance plan after changing the maintenance strategy.

I have articulated the things I know about maintenance strategy. I hope this might be helpful for someone trying to understand the philosophy behind the maintenance strategy.

Please share your valuable feedback and questions in the comment section.