Make KPI's (Maintenance)

This is the second article for KPI's serial, where we will cover the second part related to the Maintenance department.

we have covered already the production part in the last article and next articles we will cover (Quality and safety) KPI's.

Let's have another refresher for the KPI's Aims and characteristics.

The Main 4 Charatesrtics for measuring KPI's in the supply chain

1- Cost Reduction aimed.

2-Release Cash aimed.

3-Enhance a Service Level.

4- Reducing Business Waste.

What is the responsibility of the maintenance department?!

Before we jump into the responsibility, let me take you in a quick tour on the maintenance department, there are two departments under of maintenance :

1- Mechanical Departement.

2- Electrical Department.

Under each department, there are Engineers and technicians either mechanical or electrical, and those people are reporting to the maintenance manager.

Sometimes the projects department in the factories would be under the maintenance department depends on the factory hierarchy.

The main responsibilities of the Maintenance department are:

1- Reducing and optimizing the breakdowns on machines.

2-Performing all the overhauls needed for machines.

3-Implementing all the planned and preventative maintenance through the agreed cycle times.

4-Managing the maintenance budget.

KPI's for Maintenance:

1-Mean Time between Failure. (MTBF).

2-Mean Time to Repair (MTTR).

3-Maintenance Cost.

1-Mean Time between Failure (MTBF).

This time represented the average time expected from two consecutive cycles of the same failure on a specific machine or it's the expected number of operating hours before a machine has a breakdown.

Below is the formula for the MTBF:

This picture explains the meaning of the MTBF

I will go into more detail for the MTBF as the failure definition here is so generic.

Let's take an example to make it understandable, below is a picture shows a continuous flow line for laundry soap.

This line has almost 7 machines starting from the filling till the packing (end of line).

Here is the interesting part of the maintenance side, each machine is defined on the maintenance sheets or systems by code or number and considered as an asset.

For instance, in the above example, we have a line named Line 1, and under this line, there are 7 machines, each machine is coded with a number as per the above picture.

And under each machine, there is a list of well know breakdowns that are defined accordingly.

Breakdown: any machine stoppage that takes more than 10 minutes and here this loss comes under the maintenance team, not the production team.

Each breakdown is also defined by code on system or sheets, these breakdowns are almost repetitive and cyclical.

How the Breakdown got triggered Manually through the maintenance system?

Below is a sample for the Breakdown sheet that is been assigned between the line supervisor (operator) and the technician, the sheet has almost the below info:

1-Line number.

2-Machine number.

3-The Breakdown time in minutes.

4-The reason for the breakdown.

5-Signature from the Line Supervisor.

After fixing the breakdown that occurs on the line for that machine and signs this sheet, at the end of each shift, those sheets got consolidated and given to a data entry technician to feed the maintenance system with all breakdowns on machines/lines, so data will be stored accordingly.

Here it comes the calculation of the (Mean time between failure), this time can be calculated at many levels, could be calculated on the below levels:

1-Factory level including all lines.

2-Line level including all machine breakdowns.

3-Machine level breakdowns.

4-The Break down level.

The MTBF usually got reported on the factory level to give a wider view on how the factory is operating and each level you go down will help you on getting more details to attack the biggest breakdown losses and drive action plans to improve the O.E.E of the factory.

Example :

A line operates at 8 hours, this line faced 2 breakdowns, the first break down took 1.5 hours and the second break down took 0.5 hours.

How can we calculate the MTBF?

MTBF= (Total operating time-breakdown time)/Number of breakdowns= (8-1.5-0.5)/2= 6/2= 3 hours.

Then MTBF =3 Hours, means each 3 hours a breakdown appears on this line.

Note: The more MTBF, the better the result, where the best number for MTBF is infinity.

Below is an example of the MTBF over time in Min, where April 2018 was the best month.

2-Mean Time to Repair (MTTR)

It represents the average time required to repair a breakdown or it's the measurement for the "Maintabilty", and this gives you an indication of the skills and abilities of the maintenance team to repair a breakdown.

Below is the formula for the MTTR:

This picture explains the meaning of the MTTR:

This time mainly depends on the skills of the (Technicians), and how long will it take to fix a specific breakdown.

Sometimes, you will realize that the same breakdown is been fixed faster by a specific technician compared to other technicians.

And here it comes the role of the Technician/Breakdown Matrix to have a view on the breakdowns vs the technicians and taking out a correlation between (Mand Vs Failure on machines), so the output would be circulating the right pieces of training within the maintenance team, hence they can enhance the skills of other technicians so that Mean time to repair got reduced accordingly.

The same sheet that we discussed in the Meantime between failure is used to report the breakdown, Name of the technician and the time taken to fix the failure, so this info will be fed to the maintenance system as well.

This time (MTTR) needs a sincerity from technicians to think proactively to put all preventative parameters to stop these breakdowns from re-occurring again, as sometimes due to the pressure that has been set on each technician to reduce the MTTR, they can fix the breakdown just for fixation, not in a proactive way and the same breakdown could occur again in next shift with another technician, that's why maintenance Engineers and Managers should watch out from this.

Example :

A line operates at 8 hours, this line faced 2 breakdowns, the first break down took 1.5 hours and the second break down took 0.5 hours.

How can we calculate the Mean Time to Repair (MTTR)?!

MTTR= (Total breakdown times/Number of breakdowns)= (1.5+0.5)/2= 1 hour.

This 1 hour represents the average time to fix the breakdown.

Note: The Less MTTR, the better the result, where the best number for MTTR is Zero.

Below is an example of the MTTR over time in Hours, where August 2018 was the best month.

Sometimes, O.E.E (Overall equipment effectivness) would be a KPI for maintenance but (MTTR and MTBF) would serve the purpose as it will be one of the O.E.E losses under the breakdown loss tree.

3-Maintenance Cost

This is the cost of the maintenance spent on the machinery to sustain the machine status consistently in a productive way, and this cost include mainly the below:

1-Overhauling of Machinery.

2-Spare parts costs.

There is a reference for the best practice maintenance cost as a percentage.

The percentage is (2% to 9%) from the Asset value, almost of companies are using the Net- book (NBV) value form the asset not the Gross book value (GBV).

Hope that this article adds new info for you, and please don't forget the below: