Eliminate these 6 Big Losses to improve OEE

Written By

Guntapudi Udayravichandra

OEE is one of the key factors in calculating efficiency of an Automation or machines. If any factory OEE is more than 85% than the utilization of Automation or machines is very good.

In this article we will learn how to increase OEE by eliminating or reducing 6 Big Losses.

Following are the 6 Big Losses;

1. Planned Stops
2. Unplanned Stops
3. Small Stops
4. Reduced Speed
5. Production Defects
6. Startup defects

What is OEE

For calculating OEE we require 3 factors: Availability, Performance and Quality.

Product of these factors will provide OEE of a Machinery. For more details of OEE you can refer to our OEE article.

Calculation of OEE is very easy task to do with all data in Hand. To know where we got decline or decrement of OEE, we need to know about a key tool, which will let us know where the OEE got affected, on which we need to focus to improve easily.

6 Big Losses

Today we are going to learn about one of the key tools of Lean that is 6 Big losses. It will be majorly focused on what are the reasons for the decline of the OEE.

As we know there are 3 factors are used for OEE calculation. 6 Big losses are segregated into 3 parts.

1. Availability losses
2. Performance losses
3. Quality loss

Let ‘s see each Loss in Details

Availability Losses

Getting into the topic first focuses on basics on Availability.

Availability will be calculated based on the availability of Machinery.

Availability: Actual Working Minutes / Planned Working Minutes

In the above formula it states that, How much time machinery is in working condition with Planned Working Minutes.

The other 2 factors mostly rely on this Availability. If Machinery is available for most possible time, then Performance and Quality can get more percentage. If all goes as per the Standards.

There are 2 losses in Availability:

1. Planned Stops
2. Unplanned Stops

Lets go into details of first two losses of 6big losses

Planned Stops

This also can be referred to as Set up time.  While Calculation of available time, need to reduce this planned time.

Planned Stops can be defined as “Down time which will be already known when Production is Planned”.  The time which can be directly deducted while the time of Planning. i.e., Machine will be idle at the time of other works are ongoing.

The events which come under Planned stops: Changeovers, Tooling changes, Planned Maintenance, cleaning of machinery, Planned Power cuts, Program set up, Startup loss and quality inspection.

How to eliminate Planned Stops

Planned stops majorly will be affected by Changeovers.  All the production stakeholders need to work on SMED- Single Minute Exchange of Die. Since SMED is a very good tool in reduction of Changeovers time. One key thing need to counter measure is need to make Internal changeover to External changeovers. It requires some key measures how to reduce the change over time by some easy and reliable countermeasures such as;

1. Material A/B System: Since some of the factories majorly the changeover will be because of material arrangements. To reduce this kind of down time. Production should follow A/B concept. ie, Need to have 2 set of tools or material holders for changeover.  Once one set is in production flow another set should be ready for next material changeover. So while material changeover time will happen but it can be minimized.
2. Centralized Programming: Most of the scenarios, programming is done while machine is in working time. If programming is done while production, then machine will be idle so centralized programming would be a good idea. So that program is copied in a pen drive and utilized for programming. This will also reduce Programming timing while changeover.
3. Planned Maintenance: Planned maintenance is very key to make production smooth and good life for the machinery. But planning on a working day is not such a good idea. If Planned Maintenance can be planned on a non-Production Day or during break times in a working day will be better. That will not make machines idle, and production will be smooth.
4. Tools Changeovers: Since tools changeovers are key to production, proper training to Maintenance team will be a good choice in reduction of Tooling changeovers.
5. Startup loss: Start up loss cannot be controlled, if a factory runs 24hrs production then start up loss will be not such a factor. Whenever changeover then it will be affected. But some factories will plan only 2 shifts, which there will be some idle time b/w 1^st Shift and 2^nd Shift. Then there will be 2 Start-up losses for each Shift. To reduce this kind of things, factory management should plan shifts one after another to reduce startup loss from 2 times to 1 time.

These 5 are major losses which can be minimized to increase maximum availability of Machinery. If any others please comment in comment section.

Un Planned Stops

This can also require Machinery Breakdown or Down time.

Unplanned Stops can be defined as “A Equipment breakdown for more than 5mins, which not considered in Production Planning”. ie, Machine will be idle due to equipment breakdown or other factors for more than 5mints.

Unplanned Stops may be caused due to Unplanned Maintenance, Material delay from Warehouse, Unplanned power cut, Miss feeding, Due to lack of training for Operator, Spares unavailability, technical issues (Program issues, IT problems).

In this type of loss most time taking is Unplanned Maintenance. Where we should have corrective actions in quick time. To Reduce time of Machine.

How to eliminate Un Planned Stops

As these types of losses are unplanned most of them cannot be forecast but some of the losses can be reduced, not fully but can be reduced to some extent.

1. Unplanned Maintenance: These can be reduced by regular maintenance for machines and concern Maintenance need to have clear knowledge on machinery. So that the idle time cannot be more. This required proper TPM for the machinery.
2. Material Feeding delay: Material delay is also one of the key issues in unplanned breakdowns. Concern production team should be aware of WIP and stock of production. Due to material delay there could be more time for Changeover
3. Miss Feeding: Miss feeding is also another issue of down time, operators should be trained before handover of machine.
4. Unplanned Power Cuts: Unplanned power cuts also cause major down time issue. Some machines required more time to get temperature, Air pressure and working conditions into normal. So if possible, need to get UPS with machine investment. Since supplier will provide perfect UPS while manufacturing. This may reduce the power cuts issue.
5. Spares Unavailability: Many factories will face lack of spares in housed. To overcome this issue, concern production team should list out key spares which cause breakdown and need to have at least for 6months. Since most of the machinery are from oversees. Spare parts transportation will take at least 15days so need to have additional spares.
6. Technical Issues: A automation always requires a perfect IT support to make sure it always connects to Supplier when it is required since Covid most of the suppliers are working remotely. So in case of IT issues need to have IT support.

This is all about availability losses and some countermeasures to reduce.

Performance Losses

First we will look into the basics of the performance

Performance is defined based on the output of the machine on concern day.

Performance = Actual Output / Target output

The above formula states that how much output a machine produced with target output.

There are 2 losses in Performance:

1. Small Stops
2. Reduced Speed

Let’s look into 2 losses of Performance.

Small Stops

In availability loss Unplanned stop and small stops are bit identical. But the comparison is that here the time taken for the down time is less than 5minutes.

These types of losses can be quickly corrected by the concerned production operator, supervisor, or maintenance person.

How to eliminate Small Stops

This type of issue also can be followed same as Unplanned losses countermeasure to reduce small stops as well.

The major countermeasure to follow in this type of small stop is to train operators more and more to get full knowledge on frequent and periodic issues and how to correct. For this the related departments need to be on the floor all the time to make it small stops.

If Lack of training and Unavailability of related persons small stops will go as unplanned stops i.e., down time will be more than 5minutes.

Reduced Speed

Reduced speed is another killer of production. Reduced speed can happen by utilizing machine for more years. Machine cycle time will be increased and by this the productivity of the machine will be automatically reduced.

How to eliminate Reduced Speed

For enhancement of this many factories are moving to advanced machinery which will make excess investment. For this we need to follow the following.

1. Upgrade of Machinery technology: Since machinery keeps advancing from time to time. In this scenario, due to reduced speed machine productivity can be reduced to 60%~70%.  We can directly contact machine speed regarding the speed increment which will be exactly same with TT/TCT set by IE. It may require very little investment to improve or upgrade the machinery.
2. Upgrade of Spares:

A few machines may be Pneumatic which runs on air compressor if air bar is reduced machine may reduce the speed. So, if we upgrade to electrical motors then we can improve the speed of the machine

For Auto machines not all parts of a machine will be used for production, only 1 or 2 spares could be used for the speed for the machine, if we can upgrade these spares then we can automatically increase the speed of the machine.  

Based on the machinery requirement, need to list out the requirements to enhancement of speed. Then we can automatically increase the speed of the machinery.

Tip For Companies in reading: In these type of cases suppliers will ask for the new machinery maybe if company would complete AMC (Annual Maintenance Contract) with supplier. Need to upgrade AMC and then ask for the machine upgrades, it will make sure suppliers will provide. 

This is about performance losses if any support required. Comment to know.

Quality Losses

These are the 6 Big losses and well as countermeasures for each loss. Hope you learned how to minimize losses, implement the countermeasures, and let us know the results. Please comment if any support requires.

Guntapudi Udayravichandra @guntapudi

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