How to Calculate OEE for Manufacturing and Maintenance?

OEE, short for Overall Equipment Effectiveness, is a count of a production operation’s efficiency. It stamps how successfully a manufacturing line, tools, or different resources work, thinking about 3 fundamental variables, performance, availability, and quality.

This article demonstrates in detail how to calculate your OEE metric and its constituent variables. Plus, we’ll learn the formulas and computations with the help of practical examples.

Once you’ve read this complete article, you’ll have clarity about how OEE functions.

So, without wasting time, let’s get into that!

How to Calculate OEE?

OEE is an estimation utilized in Complete Productive Maintenance programs. The action incorporates machine viability and proficiency and is an evaluation metric ordinarily found in Lean Manufacturing. It helps answer 3 queries:

How regularly is the machine-accessible to run?

How quickly does it execute while it’s running?

How many quality pieces were produced?

The formula used to calculate OEE is displayed underneath:

OEE = Availability x Performance x Quality

Simply, OEE = A * P * Q

Performance Calculation

Sometimes mentioned as Efficiency, is a proportion of how well the machine executes while it is running (within the working time).

• Performance: Manufactured Pieces/ (Operating Time*Ideal Speed) * 100%
• Manufactured Pieces: unscheduled scrap and satisfactory pieces.
• Optimal Speed: ideal speed the part must execute on the machine.
• Working Time: Planned Manufacturing Time – Planned Downtime.

Availability Calculation

Availability is the measure of time the machine is accessible to run divided by the absolute conceivable accessible time. This calculation incorporates no performance numbers compared with how the equipment executes while it is running.

Availability = Operating Time/Planned Manufacturing Time

This is not quite the same as another normal measurement called Utilization. Accessibility/Availability just incorporates the time the machine was booked, arranged, or appointed to run.

Utilization can incorporate the entire hours of the day regardless of the plan. Utilization is more successful in insufficiency planning and investigating the ingestion of fixed expenses. Availability takes a look at the actual equipment itself and focuses in additional on factor cost absorption.

Operation time = Planned Manufacturing Time – Planned Downtime

Planned downtime incorporates meetings, middle breaks, and other routinely booked breaks that are independent of the equipment.

Quality Calculation

Quality is a proportion of the no. of parts within the specification contrasted with the number of were manufactured parts.

Sometimes, there is a “Planned” piece creation or “Projected” piece.

The projected piece is a hard term to utilize because every scrap is a lost benefit regardless of whether it is incorporated into the statement and cost. If a contender sorts out some way to diminish it, then you make a disadvantaged expense plan, and winning new business turns out to be all the more improbable.

For instance, if the equipment should get ready for a couple of pieces or become familiar with a task then these pieces must not be incorporated into the computation. But this addresses a possibility. Figuring out how to permanently keep away from these warm-up pieces or starting pieces is a valid improvement.

QUALITY = Acceptable Pieces/Total No. of Pieces * 100%

Total/Absolute Pieces = Acceptable Pieces + Unplanned Scrap Pieces

A test within massive creation processes is that parts from one process may not be perceived as defective until later downfall. Not in all cases, 100 percent assessment of 100 percent of the measures is practical, so imperfections might be seen as the downfall of the equipment that really made them.

This implies that really, the Quality part of OEE for that specific equipment would require to be recalculated with the lower count of Acceptable Pieces

OEE Calculation with Example

Estimating the OEE of more than an eight-hour shift that had:

• Total count of 5 scheduled break times that add up to 50 minutes.
• 10 minutes of unscheduled downtime due to a tooling disappointment.
• The best ratio of the equipment to execute this portion was estimated to be 400 pieces per minute.
• 150,000 pieces were delivered over the eight-hour shift.
• 25,000 pieces were rejected due to being out of perfection.

Now, let’s compute every component of OEE:

Availability (A)

There is an aggregate of 480 mins in a single shift. 50 additional mins were expected, so those mins will be eliminated from the denominator.

Thus, the denominator in Availability will become [480-50]/480 = 430 minutes (it is the Planned Manufacturing Time).

The Operating Time is in the numerator which eliminates the all-out Unplanned Downtime that was simply 10 mins connected with an equipment failure. Thus, the Operating Time was a total of 420 mins

Hence, A = 420 mins/430 mins = 97.67%

A Note: Keep as a primary concern, one more typical measurement estimated by organizations is Utilization. For this situation, Utilization will be 420/480 = 87.5%.

At the end of the day, no matter what the justification for lost downtime, the machine was used at 87.5% of the possible time during the shift.

Performance (P)

This response to the inquiry, how well did the equipment execute when it was running? The key phrases are “the point at which it was running” That’s why the denominator is checking out at the 420 mins of run time.

Assuming the machine must run 400 pieces each min, multiply that by 420 mins to get the count of pieces that require to have been made, which is 168,000 pieces.

The equipment really made 150,000 pieces. In this manner, there have probably have been a few losses.

Hence, P = 150,000 Pieces/168,000 Pieces = 89.29%

Quality (Q)

As there were 25,000 pieces rejected that implies 125,000 out of the 150,000 were perfect.

So, Q = 125,000/150,000 = 83.33%

To have the OEE, do A * P * Q:

OEE = 97.67% * 89.29% * 83.33% = 72.7%

Can OEE Be Over 100%?

No! An OEE value of 100 percent addresses perfect manufacturing – producing just great parts, as quick as could be expected, with no stop time.

OEE Score Evaluation

The ideal value of 100 percent generally is a definite objective. In real-life cases, think about a bunch of intervals while assessing the degree of equipment effectiveness in production.

OEE score < 65 %

An OEE value of under 65% demonstrates that there is extensive opportunity to get better because accessible limits aren’t being ideally used. In the present state, there’s an immediate need to completely evaluate the variables that are adding to stops and lost manufacturing. It’s suggested to break down often happening issues to identify and have them be solved before they can go uncontrollable.

OEE scores between 65 % and 85 %

Most assembling tasks are in this range. However, these qualities are common, they additionally show that there is an opportunity to get better. In such a case, it tends to be prudent to carry out processes for automatic advancement and constant monitoring of the processes.

OEE score > 85 %

Production tasks with an OEE value above 85% are at the highest level. They made the benchmark for other, less successful tasks to follow. With conventional equipment, however, it isn’t sensible to make progress toward a score a lot higher than 85%. A few machines utilized in the car business accomplish an OEE score of 90%, which is extraordinary. In a perfect world, proficient equipment must generally run at maximum speed without turning out any damaged parts. However, 100 percent viability is difficult to get, since even the best machines, in the long run, require upkeep or retooling.

Why is it Important to Calculate OEE?

There are 3 significant advantages of evaluating production by using:  overall equipment effectiveness:

Increasing Output Capacity

OEE assists with recognizing bottlenecks happening in processes. The key is the collection and deep evaluation of information progressively. By predicting and dispensing machine glitches, you can solve perhaps the most concerning issue in production, that’s downtime.

Decreasing Costs

Preventive upkeep based on the OEE information has another advantage. By effectively preventing costly fixes and delayed downtime, you can hold machine-related expenses in check.

Improving Productivity & Revenue

The ultimate objective of OEE enhancement is typical. To deliver more products in a similar measure of time. Joined with expanded manufacturing quality, ultimately, you’ll want to serve more clients. Furthermore, that assists in accomplishing the greater objective, generating more revenue income.

How to Improve OEE?

Numerous components impact the overall OEE score. Executing best practices like preventive maintenance, automation, or lean assembling can drastically further improve producing strategies.

Yet, everything begins with information collection. Ongoing experiences, detailing, and investigation are the foundation of upgrades. In light of the information, you can recognize the bottlenecks, flimsy points, and inadequate cycles.

Resource upkeep additionally comes into place. By getting a view of equipment, machines, or inventory network, directors can present improvements like computerized spare parts and order booking.

Sum Up

Utilizing OEE is certainly not a single measure; it can separate into different parts. It’s best used to recognize pinpoints that will take further investigation for key execution improvement. From manual, semi, to completely automatic tasks or processes, carrying out OEE devices as a component of your lean assembling protocol will further improve execution for any task in your organization.