Tag: How to Calculate OEE

OEE For Manufacturing

We are often asked what companies (or types of companies) are using OEE as part of their daily operations.  While our focus has been primarily in the automotive industry, we are highly encouraged by the level of integration deployed in the Semiconductor Industry.  We have found an excellent article that describes how OEE among other metrics is being used to sustain and improve performance in the semiconductor industry.

Somehow it is not surprising to learn the semiconductor industry has established a high level of OEE integration in their operations.  Perhaps this is the reason why electronics continue to improve at such a rapid pace in both technology and price.

To get a better understanding of how the semiconductor industry has integrated OEE and other related metrics into their operational strategy, click here.

The article clearly presents a concise hierarchy of metrics (including OEE) typically used in operations and includes their interactions and dependencies.  The semiconductor industry serves as a great benchmark for OEE integration and how it is used as powerful tool to improve operations.

While we have reviewed some articles that describe OEE as an over rated metric, we believe that the proof of wisdom is in the result.  The semiconductor industry is exemplary in this regard.  It is clear that electronics industry “gets it”.

As we have mentioned in many of our previous posts, OEE should not be an isolated metric.  While it can be assessed and reviewed independently, it is important to understand the effect on the system and organization as a whole.

We appreciate your feedback.  Please feel free to leave us a comment or send us an e-mail with your suggestions to leanexecution@gmail.com

Until Next Time – STAY lean!

OEE for Batch Processes

Coke being pushed into a quenching car, Hanna ...
Image via Wikipedia

We recently received an e-mail regarding OEE calculations for batch processes and more specifically the effect on down stream equipment that is directly dependent (perhaps integrated) on the batch process.  While the inquiry was specifically related to the printing industry, batch processing is found throughout manufacturing. Our more recent experiences pertain to heat treating operations where parts are loaded into a stationary fixed-load oven as opposed to a continuous belt process.

Batch processing will inherently cause directly integrated downstream equipment (such as cooling, quenching, or coating processes) to be idle. In many cases it doesn’t make sense to measure the OEE of each co-dependent piece of equipment that are part of the same line or process. Unless there is a strong case otherwise, it may be better to de-integrate or de-couple subsequent downstream processes.

Batch processing presents a myriad of challenges for line balancing, batch sizes, and capacity management in general.  We presented two articles in April 2009 that addressed the topic of  where OEE should be measured.  Click here for Part I or Click  here for Part II.

Scheduling Concerns – Theory of Constraints

Ideally, we want to measure OEE at the bottleneck operation.  When we apply the Theory of Constraints to our production process, we can assure that the flow of material is optimized through the whole system.  The key of course is to make sure that we have correctly identified the bottleneck operation.  In many cases this is the batch process.

While we are often challenged to balance our production operations, the real goal is to create a schedule that can be driven by demand.  Rather than build excess inventories of parts that aren’t required, we want to be able to synchronize our operations to produce on demand and as required to keep the bottleneck operation running.  Build only what is necessary:  the right part, the right quantity, at the right time.

Through my own experience, I have realized the greatest successes using the Theory of Constraints to establish our material flows and production scheduling strategy for batch processes.  Although an in-depth discussion is beyond the scope of this article, I highly recommend reading the following books that convey the concepts and application through a well written and uniquely entertaining style:

  1. In his book “The Goal“, Dr. Eliyahu A. Goldratt presents a unique story of a troubled plant and the steps they took to turn the operation around.
  2. Another book titled “Velocity“, from the AGI-Goldratt Institute and Jeff Cox also demonstrates how the Theory of Constraints and Lean Six Sigma can work together to bring operations to all new level of performance, efficiency, and effectiveness.

I am fond of the “fable” based story line presented by these books as it is allows you to create an image of the operation in your own mind while maintaining an objective view.  The analogies and references used in these books also serve as excellent instruction aids that can be used when teaching your own teams how the Theory of Constraints work.  We can quickly realize that the companies presented in either of the above books are not much different from our own.  As such, we are quickly pulled into the story to see what happens and how the journey unfolds as the story unfolds.

Please leave your comments regarding this or other topics.  We appreciate your feedback.  Also, remember to get your free OEE spreadsheets.  See our free downloads page or click on the file you want from the “Orange” box file on the sidebar.

Until Next Time – STAY lean!

Vergence AnalyticsVergence Analytics

OEE: Frequently Asked Questions

We added a new page to our site to address some of the more frequently asked questions (FAQ’s) we receive regarding OEE.  We trust you will find this information to be of interest as you move forward on your lean journey.  We always appreciate your feedback, so feel free to leave us a comment or send an e-mail directly to LeanExecution@gmail.com or Vergence.Consulting@gmail.com

We have had an incredibly busy summer as more companies are pursuing lean manufacturing practices to improve their performance.  OEE has certainly been one of the core topics of discussion.  We have found that more companies are placing a significant emphasis on Actual versus Planned performance.  It would seem that we are finally starting to realize that we can introduce a system of accountability that leads to improvements rather than reprimands.

Keep Your Data CLEAN

One of the debates we recently encountered was quantity versus time driven performance data when looking at OEE data.  The argument was made that employees can relate more readily to quantities than time.  We would challenge this as a matter of training and the terminology used by operations personnel when discussing performance.  We recommend using and maintaining a time based calculation for all OEE calculations.  Employees are more than aware of the value of their time and will make every effort to make sure that they get paid for their time served.

Why are we so sure of this?  Most direct labour personnel are paid an hourly rate.  Make one error on their pay or forget to pay their overtime and they will be standing in line at your office wondering why they didn’t get paid for the TIME they worked.  They will tell you – to the penny – what their pay should have been.  If you are paying a piece rate per part, you can be sure that the employees have already established how many parts per hour they need to produce to achieve their target hourly earnings.

As another point of interest and to maintain consistency throughout the company, be reminded that finance departments establish hourly Labour and Overhead rates to the job functions and machines respectively.  Quite frankly, the quantity of parts produced versus plan doesn’t really translate into money earned or lost.  However, one hour of lost labour and everyone can do the math – to the penny.

When your discussing performance – remember, time is the key.  We have worked in some shops where a machine is scheduled to run 25,000 parts per day while another runs a low volume product or sits idle 2 of the 5 days of the the week.  When it comes right down to the crunch for operations – how many hours did you earn and how many hours did you actually work.

Even after all this discussion we decided it may be an interesting exercise to demonstrate the differences between a model based on time versus one based (seemingly) only on Quantitative data.  We’ll create the spreadsheet and make it available to you when its done!

Remember to take advantage of our free spreadsheet templates.  Simply click on the free files in the sidebar or visit our free downloads page.

We trust you’re enjoying your summer.

Until Next Time – STAY Lean!

Vergence Business Associates

OEE Topics for 2009

We changed our theme!

Today was another day to do a little maintenance. We spent a little time revamping our look and feel. We hope you enjoy the changes and find our site a little easier to navigate.  We updated our Free Downloads page to present another easier and more direct venue to get your files instantly using Box.Net. If you’re already familiar with WordPress, you know how great this widget is. Downloads could never be faster or easier.

We also took some time to update some of our pages. We would suggest, however, that the best detailed content appears in the individual articles that we have posted.

Upcoming Topics for 2009

  1. Tracking OEE Improvements:  We have noticed an increase in the number of requests to discuss tracking OEE improvements.  We have been working on a few different approaches even for our own consulting practice and look forward to sharing some thoughts and ideas here.
  2. How OEE can improve your Cost of Non-Quality.  It’s more than yield.
  3. What OEE can do for your Inventory.  Improvements should be cascading to other areas of your operation – including the warehouse.
  4. Innovation – Defining your future with OEE
  5. OEE and Agile – Going beyond lean with OEE.
  6. Best Practices – OEE in real life, in real time

If you would like to suggest a topic for a future post, ask a question, or make a suggestion, please leave a comment or simply send an e-mail to LeanExecution@gmail.com or vergence.consulting@gmail.com.  We do appreciate your feedback.

Until Next Time – STAY lean!

Vergence Business Associates

We respect your privacy, your information will not be shared, sold, or distributed to any third parties.  We will only use your e-mail to communicate with you at your request.  You will not be subject to any advertising or marketing campaigns.

OEE Training – Online

Getting Started

Online Training is more rampant now than ever.  If you want to learn about OEE and how to calculate it correctly then we have all the information you need right here.  Simply click on the categories of interest to you and research your specific topic or Click Here to get started.  This is the first article that got us started in November of 2008.  All of our online content is presently available at no charge.

Free Spreadsheet Templates

We offer several OEE Spreadhseet Templates that are available at no cost to our visitors and clients. Feel free to click on the “Free Downloads” template on the sidebar.  This is a new feature and trust that you will find this a much easier solution that provides immediate access to our documents.  If you can’t find what you are looking for, contact us by e-mail (leanexecution@gmail.com) or leave a comment with your suggestions for other templates that you would like to see available on our site.

Advanced Visitors

We trust that the content presented here is of interest to you as well.  We have provided many articles of interest related to OEE and Lean.  Simply review the categories and posts available or visit our pages for more information.  Our articles present detailed discussions and best practices applicable to the featured topic.

If you have any questions, comments, or suggestions for a future topic, simply leave a comment or send an e-mail to leanexecution@gmail.com or vergence.consulting@gmail.com.  We respect your privacy.  We will not share, disclose, sell, or distribute your e-mail or personal information with any third parties.  Your e-mail will only be used to contact you at your request.  You will not be subject to any advertising or marketing campaigns.  See our privacy policy for more details.

Until Next Time – STAY lean!

Vergence Business Associates

OEE Integration: Can you fix it?

As we are all aware, inspecting or measuring parts does not change the quality of the product.   Likewise, measuring and reporting OEE alone does not solve problems or improve performance.  While it is fair to say that increased focus and measurement of any process usually results in some degree of improvement, these are typically attributed to changes in human behavior due to observation and not necessarily real process improvements.

Using OEE to identify opportunities in your operation is the equivalent of turning the light on in a dark room.  Although the room hasn’t changed, we certainly have a better understanding of what it looks like.  As such, OEE is a vantage point metric that can be used to illuminate our understanding of the process and identify opportunities to drive improvements.

It is essential for your team to develop and utilize effective problem solving skills to successfully identify systemic and process root causes for failure and to develop and execute permanent corrective actions to resolve them.  Our experience suggests that the lack of solid and proven problem solving skills coupled with poor execution is the leading cause of failure for new initiatives such as OEE.

We introduced an approach to improving OEE in our “Improve OEE:  A Hands On Approach“, post (03-Jan-09).  Although we identified some of the tools that could be used to solve of the problems, we didn’t spend much time going into the details.  Over the next few posts, we’ll discuss some of the ideas in a little more detail.

The real problem for most companies is identifying what the real underlying root cause of the current “failure” mode is.  Without a good understanding of the root cause, the solutions developed and implemented will not be effective, only serving to temporarily cure the immediate superficial symptoms.

Using effective problem solving skills to analyze the OEE data and to develop and execute permanent corrective actions will assure sustainable and ever improving performance.

Until Next Time – STAY lean!

OEE Where do we Measure – Part II

We have stated that policies and procedures will have an impact on your OEE implementation strategy.  One reader commented on Part I of this post stating that “OEE should be measured at the ‘design’ bottleneck process / piece of equipment that sets the pace of the line.”  While this is certainly an effective approach, the question is whether or not company policy or procedure supports the measurement of OEE in this manner.  Nothing is as simple as it looks.  Take this to the boardroom and see what kind of response you get.  We’re flexible.

As such, this becomes yet another consideration for what is being measured, how the data going to be used, and what is the significance of the results.  While we didn’t elude to a multi-series post, the comment was indeed timely.  The risk of not understanding the data could result in other inefficiencies that are built into the process that could mask either upstream or downstream disruptions.

Inventory – Hiding Opportunities

Whenever we think of the “bottleneck”, we instantly turn to the Theory of Constraints.  The objective is to ensure that the bottleneck operation is performing as required – no disruptions.  In many cases, process engineers will anticipate the bottleneck and incorporate buffers or safety stock into the process to minimize the effect of any potential process disruptions.

On one hand, the inventory, whether in the form of off-line storage or internalized, by using a buffer (or part queue), will in essence minimize or eliminate the effects of external disruptions.  On the other hand, there is a premium to be paid to carry the excess inventory as well.

While buffers or part queue’s can serve as a visual indicator of how well the process is performing, assuming the method used to calculate the queue quantities is correct, our previous post was eluding to the fact that many manufacturers incorporate contingency strategies into the process after the fact such as inventory that was not part of the original process design or reworking product on line.

Incorporating a rework station as part of the manufacturing process because the tooling or equipment is not capable of producing a quality part at rate may eventually be absorbed as part of the “normal” or standard operating procedure.  As such, it is important to manage standardized operating procedures in conjunction with Value Stream Maps to avoid degradation from the base line process.

OEE can serve as an isolated diagnostic tool and as a metric to monitor and manage your overall operation.  Company policy should consider how OEE is to be applied.  While most companies manage OEE for all processes, they are typically managed individually.  Many companies also calculate weighted department, plant, and customer driven OEE indices.

Regardless of the OEE index reported, it is important to understand the complexities introduced by product mix and volumes when considering the use of a weighted OEE index.  The variability of the individual OEE factors compounds the understanding of the net OEE index even more.

We have provided FREE Files for you to download and use at your convenience.  A detailed discussion is also provided in our OEE tutorial.  See the “FREE Files” BOX on the sidebar.

We look forward to your comments.  If you prefer, please send an e-mail to leanexecution@gmail.com

We look forward to hearing from you.

Until next time, STAY – lean!

OEE Calculation Errors

Database Errors

We agree that collecting and tracking OEE data is a task best suited for a database, however, all the bells and whistles of an OEE system don’t serve much purpose if the calculations are wrong.  Before you make a significant investment in your OEE data collection, tracking, and monitoring system, make sure the system you plan to purchase is calculating the OEE results correctly.

The ultimate system is one that supports automated data collection technology to minimize data entry costs, reduces the risk of entry errors, and provides reporting or monitoring of OEE in real time.  These solutions may be purchased “off the shelf” or customized to your specific process application.

Excel Spreadsheets

If a database is the best approach, you may ask why we use Excel spreadsheets to present our examples or why we supply templates to allow you to track and monitor OEE.  We have four primary reasons:

  1. Almost everyone is familiar with spreadsheets and most people have access to them on their computer.
  2. We determined that a customized database solution being used was not calculating the weighted OEE factors correctly and the overall OEE index was also wrong.  We found it necessary to develop a spreadsheet that made it easy to validate the database calculations.
  3. Database enhancements were easier to develop and demonstrate using a spreadsheet.  We encountered a production process that was equipped with automated data collection capability and provided an overwhelming amount of performance data in real time.  It was easier to perform database queries and use the power of PIVOT tables to develop the desired solutions.
  4. Spreadsheet templates allow you to start collecting and analyzing data immediately.  It also allows the users to get a “feel” for the data.  Although the graphs and drill downs offered by databases are based on predetermined rules, humans are still required to make sense of the data.

Recommendations

In summary, validate the software and its capabilities prior to purchase.  We have observed installations where the OEE data is used to monitor current production performance and the reports generated by the system are used to support the results – good or bad.

We have also evaluated a number of other free OEE spreadsheet offerings on the web and observed that some of these also fail to correctly calculate OEE where multiple machines or part numbers are concerned.  Take a look at our free spreadsheets offerings (see the sidebar).  Our tutorial provides an in depth explanation of how to calculate OEE for single and multiple machines or parts.

The purpose of measuring OEE is to ensure sustained performance with the objective to continually improve over time.  Don’t fall into the trap of setting up a system that, once installed, will only be used to generate reports to justify the current results.

Take the time to train your team and demonstrate how the results will be used to improve their processes.  Involve all of your employees from the very beginning, including the system selection process, so they understand the intent and can provide feedback for what may be meaningful to them while, in turn, they can support the company’s goals and objectives.

Reference Posts.

We encourage you to visit our previous posts showing how to calculate OEE for multiple parts and machines.

  1. Single Process – Multiple Shifts:  OEE

  2. Multiple Parts / Processes:  OEE

  3. Practical OEE

  4. Weighted Calculations:  OEE

  5. How to Calculate OEE

  6. Overall Equipment Efficiency

If you have any questions, comments, or wish to suggest a topic for a future post, please forward an e-mail to leanexecution@gmail.com

We appreciate your feedback.

Until next time – STAY Lean!

OEE: Take the Hit

The simplicity of measuring and calculating OEE is compounded by the factors that ultimately influence the end result.  Because the concept of OEE can be readily embraced by most employees, it is easy for many people to get involved in the process of making improvements.

Unfortunately the variables involved with OEE, like those of many other measurement systems, fall under scrutiny.  The goal of achieving yet even higher OEE numbers is met with yet another review of the factors and how they are treated.  Usually the scope of this often heated discussion is focused on Availability.

The greatest task of all occurs when attempting to classify what qualifies as planned versus unplanned downtime.  Availability is the primary factor where significant improvements can be realized and is most certainly the focus of every TPM program in existence.  However, another significant factor that can greatly impact Availability is setup time.

We still receive questions and comments from our readers regarding setup time and whether or not they should “take the hit” for it.  We have met up with different rationale and reasoning to exclude setup time from the availability factor such as:  “We have all kinds of capacity and do the setups in our free time.” Or, “We do the setups on the off shift so the equipment is always ready when the first shift comes in.”

Regardless of the rationale, our short answer to the question of inclusion for setup time remains a simple, “Yes, take the hit.”  Before we get to much further let’s define what it is.  Setup time is typically defined as the time required to change or setup the next process.  The duration of time is measured from the last good part produced to the first good part produced from the new process.

Improving setup times provides for shorter runs, reduced inventories, increased available capacity, increased responsiveness, improved maintenance, and in turn, improved quality.  Shorter runs also provide the opportunity to maintain tools more effectively between runs as they are not as subject to excessive wear caused by longer run times and higher production levels.

Setup and Quick Die Change / Quick Tool Change

An exhaustive amount of work has been completed in many manufacturing disciplines to reduce and improve setup times.  Certainly, by simply ignoring the setup time, there is no real way to determine whether the new methods are having an impact unless another measurement system for setup is introduced.  We already have a measurement system in place, so why invent another one?

Quick Die Change and other Quick Tool Change strategies are common place in industries such as automotive stamping plants.  The objectives for Quick Die Change are attributed to LEAN principles such as single part flow and reduced inventories.  The benefits of these efforts, of course, extend to OEE and availability.

Setup and Production Sequencing

To exemplify the effect of sequencing and setup, consider a single tool that makes 8 variations of a product.  For the sake of discussion, let’s assume the only difference is the number of holes punched into the part.  The time for each punch removed from, or added to, the tool is the same.

The objective for scheduling this tool is quite obvious.  We need to minimize the number of punch changes to minimize the downtime.  If the parts required range from 1 hole to 8 holes, and we need 100 parts of each variant, we would arrange the schedule in such a manner as to make sure we are only adding one punch to the tool as we move on to the next variant.

In this case, setup time and sequencing are clearly a cause for concern and consideration.  Secondly, it is much easier to calculate the time required to run all the parts and how much capacity is required.  Including setup in the OEE factor also simplifies the calculation of overall capacity utilization for the piece of equipment in general.

In Conclusion

As we have stated in previous posts, the objective of measuring OEE is to identify opportunities for improvement.  Achieving higher numbers through the process of debate and elimating elements for consideration is not making improvements.  Don’t masquerade the problem or the opportunities. 

Setup is certainly one area where improvements can be measured and quantified.  Availability and OEE results provide an opportunity to demonstrate the effectiveness of these improvements accordingly.

If the leadership of the company is setting policy then the explanations for performance in this regard should be understood.  The only numbers that really matter are on the bottom line and hopefully they are black.

We would also encourage you to visit two of our recent posts, Improving OEE – A hands on approach (posted 03-Jan-09) and OEE and Availability, (posted 31-Dec-2008).

Until next time, stay LEAN.

OEE and Overtime

A number of requests have been received recently that point to a lack of clarity in the definition of Overall Equipment Effectiveness (OEE).  One of the questions we were recently asked is:

How do you calculate OEE for Overtime hours?

Overtime and OEE

Our first response is quite simple.  OEE doesn’t care whether you are working overtime or straight time.  The basic OEE definition pertains to equipment effectiveness.  If the machine is scheduled to run production, the same basic calculations apply regardless of the day or hours worked.

If your machine is running two shifts and customer requirements increase to the point where you no longer have capacity to meet demand , two choices exist:  either work overtime or add an additional shift to make up for the shortfall.  In both cases, the production time would be scheduled.

If capacity should be available but simply isn’t because of extenuating circumstances such as poor quality (material or process) or equipment condition, the same rules still apply.  Production is scheduled, therefore machines must run to meet customer demand.  The difference in this case is not increased customer demand but rather the inability to produce parts due to extenuating equipment or process conditions.

While appropriate action should be taken to address the reason(s) for working overtime, the fact that you are working it should not change the method used to calculate OEE.

This question, like many others we receive, reinforce our recommendation to clearly state what is being measured and why.  We also stated in previous posts that OEE is relative for your organization – a standard industry wide definition for OEE exists only by way of calculation.  The elements and how they are to be considered for calculation purposes are subject to company policy.

We appreciate the feedback and look forward to hearing from our readers.  To submit your questions, comments, or suggest a topic for a future post, send an e-mail to LeanExecution@gmail.com

Until next time – stay LEAN.