How to Calculate OEE – The Real OEE Formula with Examples

December 3, 2008 Leave a comment Go to comments
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A lot of time and effort can be wasted collecting data and analyzing the results.  Fortunately, Overall Equipment Effectiveness, or OEE, is one of those metrics that is easily calculated and can be applied to any process, department, or the entire organization.

We have created  a number of Excel spreadsheets that are immediately available from our FREE Downloads page or from the Free Downloads widget on the side bar.  These spreadsheets can be modified as required for your application.

OEE is comprised of three factors:  Availability, Performance, and Quality.  While calculating these factors is fairly straightforward, it is important to recognize that a standard industry definition for OEE does not exist.  It is important to understand the assumptions you are making to make sure that you understand the final OEE result.  This is increasingly more important when attempting to compare the results of one department or plant against the performance of another.

OEE measures how effectively TIME is used to produce a quality product.  We have established the following definitions of TIME to be used to calculate OEE:

  1. Scheduled Production Time or Planned Production Time
  2. Planned Down Time:  Scheduled down time events
  3. Unplanned Down Time:  Unscheduled down time events
  4. NAT = Net Available Time (Scheduled Production Time – Planned Down Time)
  5. NOT = Net Operating Time (Net Available Time – Unplanned Down Time)
  6. IOT = Ideal Operating Time (Time to Produce All Parts at Rate)
  7. LOT = Lost Operating Time Due to Production of Scrap or Non-Saleable Product.

Although we will provide examples of these calculations, the following formulas are used to calculate each of the OEE factors and overall OEE:

  1. Availability % = NOT / NAT * 100
  2. Performance % = IOT / NOT * 100
  3. Quality = (IOT – LOT) / IOT * 100
  4. OEE = Availability * Performance * Quality

You will notice that a quick way to check your OEE result is to calculate the time required to make good parts divided by the Net Available Time:

OEE = (IOT – LOT) / NAT

A word on Availability:

Availability is based on the actual “scheduled production time”.  Assuming a production process is scheduled to run over an 8 hour shift or 480 minutes (60 * 8), the following definitions are applied for planned and unplanned downtime.

Planned Downtime:

  1. Scheduled break times.
  2. Scheduled clean up at the end of the shift.
  3. Scheduled Preventive Maintenance.

Unplanned (Process/Equipment) Downtime:

  1. Setup / Tool Changes
  2. Material Changes
  3. Material Handling
  4. Quality Concerns
  5. Process Downtime
  6. Equipment Failures
  7. Personnel Relief

While it could be argued that setup or tool changes are planned events, they are considered part of the overall production process.  If tool change or set up events affect equipment or capacity utilization, then an effort to reduce these times will reflected by improved availability and an increase in available capacity.  It also makes capacity utilization much easier to calculate.  Again, knowing what is in the definition is important.  The purpose of establishing OEE is to drive improvement in your organization.  For example, Quick Die Change, or SMED, programs are specifically geared to improve the change over process.  If a separate program is used to manage the change over process, then you may so choose to leave this activity as a separate entity.

A word of caution! OEE is a metric, not a program.  Use existing systems and processes wherever possible to manage or support your OEE activities at launch.  New initiatives often fail because they are introduced in isolation and are often accompanied by “new ways” of doing business and tend to disrupt other existing work flows.  A true improvement or initiative that saves the company time and money will stand on its own merits.  This same initiative can be acted upon regardless of whether an “OEE Improvement Plan” exists.

I highly recommend reading Velocity: Combining Lean, Six Sigma and the Theory of Constraints to Achieve Breakthrough Performance – A Business Novel.  This engaging story exemplifies the challenges of integrating new initiatives into a company and how to overcome them.  This book ranks among the best with other books like The Goal.

Calculating OEE:  A real life example

An 8 hour shift is scheduled to produce three parts as shown in the schedule below.  The shift has two 10 minute breaks and a 5 minute clean up period.

Production Schedule:

  • M/C:  A   Part #:  A123, Cycle:  10 (seconds), Produced:  2240, SCRAP:  50, Unplanned Downtime:  32 minutes
  • M/C:  B   Part #:  B456, Cycle:  45 (seconds), Produced:  450, SCRAP:  25, Unplanned Downtime:  18 minutes
  • M/C:  C   Part #:  C789, Cycle:  70 (seconds), Produced:  229, SCRAP:  11, Unplanned Downtime:  22 minutes

Lets start by calculating our time factors for each machine:

Net Available Time:  Since each machine is scheduled to run for the full 8 hour shift, the Net Available Time for each machine is calculated as follows:

  1. Scheduled Time = 8 hours = 480 Minutes (8 * 60)
  2. Planned Down Time = 2 breaks * 10 minutes + clean up 5 minutes = 25 minutes
  3. Net Available Time (NAT) = 480 – 25 = 455 minutes

Machine A

  1. Unplanned Downtime = 32 minutes
  2. Net Operating Time (NOT) = Net Available Time – Unplanned Downtime
  3. NOT = 455 – 32 = 423 minutes
  4. Ideal Operating Time (IOT):  2240 total parts * 10 seconds = 22400 / 60 = 373.33 minutes
  5. Lost Operating Time (LOT):  50 scrap parts * 10 seconds = 500 / 60 = 8.33 minutes

Machine A:  OEE Factors are calculated as follows:

  1. Availability:  NOT / NAT = (423 / 455) * 100 = 92.97 %
  2. Performance:  IOT / NOT = (373.33 / 423 ) * 100 = 88.26%
  3. Quality:  (IOT – LOT) / IOT = (373.33 – 8.33) / 373.33 * 100 = 97.77%
  4. OEE = A * P * Q = 92.97% * 88.26% * 97.77% = 80.22%

We could also have calculated OEE using the Quick Check as shown below:

Time to produce good parts ONLY:  373.33 – 8.33 = 365

OEE = (IOT – LOT) / NAT = (373.33 – 8.33) / 455 * 100 = 80.22%

Using the same formulas as above the time factors for Machines B and C follow.

Machine B

  1. Unplanned Downtime = 18 minutes
  2. Net Operating Time (NOT) = Net Available Time – Unplanned Downtime
  3. NOT = 455 – 18 = 437 minutes
  4. Ideal Operating Time (IOT):  450 total parts * 45 seconds = 20250 / 60 = 337.5 minutes
  5. Lost Operating Time (LOT):  25 scrap parts * 45 seconds = 1125 / 60 = 18.75 minutes

Machine B:  OEE Factors are calculated as follows:

  1. Availability:  NOT / NAT = (437 / 455) * 100 = 96.04 %
  2. Performance:  IOT / NOT = (337.5 / 437 ) * 100 = 77.23%
  3. Quality:  (IOT – LOT) / IOT = (337.5 – 18.75) / 337.5 * 100 = 94.44%
  4. OEE = A * P * Q = 96.04% * 77.23% * 94.44% = 70.05%

We could also have calculated OEE using the Quick Check as shown below:

Time to produce good parts ONLY:  337.5 – 18.75 = 318.75

OEE = (IOT – LOT) / NAT = (337.5 – 18.75) / 455 * 100 = 70.05%

Machine C

  1. Unplanned Downtime = 22 minutes
  2. Net Operating Time (NOT) = Net Available Time – Unplanned Downtime
  3. NOT = 455 – 22 = 433 minutes
  4. Ideal Operating Time (IOT):  229 total parts * 70 seconds = 16030 / 60 = 267.17 minutes
  5. Lost Operating Time (LOT):  11 scrap parts * 70 seconds = 770 / 60 = 12.83 minutes

Machine C:  OEE Factors are calculated as follows:

  1. Availability:  NOT / NAT = (433 / 455) * 100 = 95.16 %
  2. Performance:  IOT / NOT = (267.17 / 433 ) * 100 = 61.70%
  3. Quality:  (IOT – LOT) / IOT = (267.17 – 12.83) / 267.17 * 100 = 95.20%
  4. OEE = A * P * Q = 95.16% * 61.70% * 95.20% = 55.90%

We could also have calculated OEE using the Quick Check as shown below:

Time to produce good parts ONLY = 267.17 – 12.83 = 254.34

OEE = (IOT – LOT) / NAT = (337.5 – 18.75) / 455 * 100 = 55.90%

Our next post will show you how to calculate a truly weighted OEE based on the examples given here.

Until Next Time – STAY Lean!

If you have any questions regarding this post or simply want more information, please feel free to send an email to leanexecution@gmail.com

Twitter: @Versalytics
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  1. September 22, 2011 at 7:18 am

    Very helpful !!!

  2. Beatriz Simões
    October 8, 2011 at 9:37 am

    I like very much this site because the comments are based in pratical applications and help a lot of users.
    I have a doubt.

    The performance efficiency is a factor in the calculation of OEE. It is a function of cycle time (theoretical time to produce a unit of product):

    Performance Efficiency = (Ideal Cycle Time x Total Prod Qt) / Net Operating Time) x 100

    Total Prod Qt: total quantity of products

    Cycle time is easily measured in continuous production lines.
    However, I am calculating the OEE for a batch process equipment.
    It is a tablet coating equipment. We fill the machine with the entire batch of tablets, the process is carried out and then we discharge the batch of coated tablets. I was thinking of dividing the batch production time by the total number of tablets processed to determine the cycle time of each batch, but I don`t know if it is correct to call it cycle time? Is there another formula to calculate the performance for batch processes?

    Another question. I would like to calculate the capacity of this equipment using OEE, but I need an academic reference of it. Do you know any? As I am attending a master´s degree program and my project will be about the application of OEE in the pharmaceutical industry, I need to reference this calculation.

    Thanks in advance

  3. bhagath singh
    February 7, 2012 at 10:19 am

    hello sir…,
    this is bhagath singh, i use zonal centrifuse… how i will get OEE

    • February 12, 2012 at 8:57 am

      OEE does not depend on the type of equipment you are using, only the cycle time for your process.

  4. Mark
    June 20, 2012 at 5:32 am

    Hi Sir i would to know hould can i get the “cycle time” for production of goods or per scheduled production. please answer me as soon as you read this comment. thank you so much

    • June 20, 2012 at 10:27 pm

      Hi Mark, thank you for your comment. I trust the following will help to answer your question.

      The cycle time is the ideal amount of time required to produce a part or product. In my experience, one machine or process may be used to run a variety of parts, each requiring a different cycle time due to size, shape, complexity, or other factors directly attributed to the product itself.

      As such, I recommend performing a time study to determine the cycle time for each part or product that is produced in a given machine. As improvements are introduced, additional time studies will be required to maintain your standards.

      For automated processes, such as automated assembly lines or robotic welding operations, the cycle time is typically stated or shown on the PLC or machine controller and can also be confirmed through a simple time study.

      Processes that are driven by human effort (manual operations) are typically measured using the “button to button” time. The cycle time begins when the operator starts the machine and ends when the operator starts the machine again to produce the next part. This assures that all loading and unloading activities are captured in the total cycle time.

      Note that some companies use the “machine capacity rate” or “plate” rate. For example, a press may be rated to run up to 60 strokes per minute yielding a cycle time of 1 second while the tooling may only be capable of running at 30 strokes per minute yielding a cycle time of 2 seconds.

      I recommend using the part specific cycle time, however, your plant policy may state that the “machine capacity rate” is the goal.

      To establish your cycle time, I recommend performing a time study over a reasonable period of time and sufficient quantity of parts (suitable for your process) to capture any slight variances that may occur during the machine cycle and over the course of the run.

      For processes that rely on human effort alone, it is important to consider factors such as fatigue. This is one of the many reasons that job rotation is becoming common place in many plants.

      As a final note, the Performance factor for your OEE should not exceed 100% as this implies that the process was running faster than the ideal cycle time you already established. If this is the case, understand what changed, document, and perform another time study to update your standard.

      I trust this meets with your immediate requirements and thank you for your question.

  5. Mohammed Raheemuddin
    June 27, 2012 at 4:48 pm

    Really this help me alot in improving OEE, If you could provide me the downtime calculation like MTTr, MTBF Etc……

    • July 1, 2012 at 2:15 pm

      Thank you for your comment Mohammed, I’m glad to hear that we have helped to make improvements in your OEE. MTTR and MTBF are based on data collected over time and are summarized as follows:

      MTTR – Mean Time To Repair = Total Corrective Maintenance Time / Total Number of Corrective Maintenance Actions.

      Note that some companies distinguish between response time and actual repair time. For example, it may take someone 15 minutes to respond to a 5 minute repair. The objective is to both minimize the response time and the repair time.

      MTBF – Mean Time Between Failures = Total Operating Time / Total Failures
      Where, Total Operating Time is the actual machine UP Time

      A good application for MTTR and MTBF can be found in spot welding operations where tip changes are quite frequent. Data can be collected over a relatively short period of time to determine the real life of a weld tip before it must be “dressed” or replaced altogether.

      Thank you for visiting with us.

  6. Vinayak
    August 22, 2012 at 11:53 am

    Does Tool change / Tool index downtime come under availability or Performance ?

    • August 23, 2012 at 6:40 am

      If the Tool change or Tool index time is incurred during the cycle time required to produce a part, the “down time” falls under Performance.

      The time required to complete one full production cycle (“button to button” or “start to start”) is the cycle time. Operations or sequences that occur during the cycle are all inclusive in the cycle time.

      If the tool change is required to produce a different part, the down time falls under Availability.

      Thank you for visiting!

  7. Manoj Gupta
    September 2, 2012 at 5:48 am

    Sir, Please explain how to calculate performance in more detail.

    …Thank you Sir …

    • September 4, 2012 at 6:14 am

      Manoj, thank you for visiting our site.

      Our “How to Calculate OEE – Tutorial” is available for download free of charge and thoroughly explains how to calculate all of the factors for OEE.

  8. B K Das
    November 1, 2012 at 9:45 am

    OEE has fascinated maintenance world for quite some time and dominated the discussion space also in a significant way. But I feel while it may have served the purpose of integrating some factors affecting the performance of a plant related to maintenance it has limited us also. It is time for critical analysis of this term and its validity also.
    I am not going to repeat some of the limitations of OEE which has been spoken about in the past such as treating 20%*80%*90% equal to 40%*60%*60% whereas they are not and not acknowledging the relative weightage of the three factors or the cost associated with them etc.
    Instead I am going to speak of two aspects of it:
    1. How do we make use of information on OEE? Obviously we break it into the three components and analyse each of them separately and make an action plan on each of them. What is the additional value derived by it in such a case?
    2. The value of OEE may be in fact giving wrong indication. Look at the following example:

    Let us take a plant suppose to produce 1 component per hour under normal circumstances and let us consider a 30 days month.

    It is shutdown for maintenance for 12 hrs in a month and has a breakdown for 6 hrs. Hence the availability is = (720-12-6)/720*100 = 97.5%
    (loss of production= 18 components)

    Let us assume it had problem in one of the machines foe which they had to run it at reduced rate (75%) for 12days. Though the machine did not stop producing but correcting the vibration problem took long. Hence the speed factor is =(18+0.75*12/30*100 = 90%
    (loss of production= 72 components)

    Let us further assume there was a fault in one of the machines which started generating 6defects per day and it took 3 days to diagnose and rectify it. Hence the quality factor is = (30*24-6*3)/(30*24)*100 = 97.5%
    (loss of production= 18components)

    Let us look at OEE. OEE = (0.975*0.90*0.975)*100 = 85.6%
    If we calculate loss of production by this it is = 720*14.4/100 = 103.7

    Whereas the loss of production actually is = 18+72+18 = 108 which will be reflected by the actual availability figure of 100-2.5-10-2.5 = 85.

    In this example the difference is only 0.6% but one can take more extreme value and find out that it is in fact much more.

    Hence while I fully agree that being aware of, measuring, keeping track of and making action plan against all the three factors is absolutely essential, the more meaningful way is the conventional way. All aware organisations measure all three convert them into equivalent and make action plan for improvement against all of them. If at all there is meaning full way of combining them it is addition. We may give it a name, let’s say Overall Performance for simplicity.

    • November 2, 2012 at 7:23 am

      Thank you for your comment. I trust the following will clarify our perspective and also address our concerns regarding your application of the OEE formulas as described in the scenario presented. You will find that the correct application of the formulas for OEE will yield the identical result.

      1. The objective of OEE is not necessarily to create 3 separate action plans, 1 for each of the factors. Rather all factors should be considered as a whole to determine whether correlations between factors exists. The factors serve to isolate 3 aspects of the process that may be contributing to reduced OEE.

      A poorly maintained process can result in excessive cumulative downtime for “band aid” fixes, reduced cycle times (lower performance), and increased quality defects. From this perspective, a single and proper process fix resolves three “correlating” factors.

      In other words, the factors serve to identify both correlating and individual incidents or conditions that may affect them.

      2. Regarding your calculations of OEE, you are attempting to calculate TEEP (Total Equipment Effectiveness Performance), not OEE. As a result, it appears that there is some confusion with the application of the formulas to calculate OEE as well.

      Planned maintenance is not considered as available operating time and therefore is not a factor in the OEE calculation, however, it is required for TEEP.

      Total Time Available = 30 days * 24 hours = 720 hours
      Net Available Time = Total Time Available – Planned Downtime
      Net Available Time = 720 – 12 = 708 hours

      Planned Availability = Net Available Time / Total Time Available = 708 / 720 = 98.33%

      OEE Availability as presented by your “scenario” should be as follows:

      Net Available Time = 720 – 12 hours = 708
      Net Operating Time = 708 – 6 = 702 hours

      OEE Availability = Net Operating Time / Net Available Time = 702 / 708 = 99.43%

      The cumulative (TEEP Availability * OEE Availability) factor is (98.33% * 99.43%) = 97.77%

      Performance as presented by your “scenario” is also incorrect. Your formula assumes 30 days of net operating time when in fact only 702 hours are available after accounting for lost availability. The resulting performance calculation should be as follows:

      If the machine was operating at 75% for 12 days, the performance loss for 12 days = 25%. Therefore, the Ideal Operating Time is calculated as follows:

      Ideal Operating Time = Net Operating Time – Performance Lost Time
      Ideal Operating Time = 702 – 25%*(12*24) = 702 – 72 = 630 hours

      Performance = Ideal Operating Time / Net Operating Time = 630 / 702 = 89.74%

      Finally, the Quality factor is Net Value Added Time / Ideal Operating Time

      Value Added Time = Ideal Operating Time – Quality Losses
      Value Added Time = 630 – (6 * 3) = 612

      Quality = Value Added Time / Ideal Operating Time = 612 / 630 = 97.14%

      OEE = Availability * Performance * Quality
      OEE = 99.43 * 89.74 * 97.14 = 87.2%

      TEEP = 98.33% * OEE = 98.33 * 86.67%
      TEEP = 85.23%

      Calculation variance is the result of rounding only. Not error introduced as a result of the formulas themselves.

      In summary,

      Multiplying each of the factors together, Availability * Performance * Quality, should yield the same result as the following formula:

      OEE = Ideal Time * Total Good Parts Produced / Net Available Time

      OEE = 612 / 702 = 87.2%
      TEEP = 612 / 720 = 85.0%

      This formula easily confirms whether the resulting OEE calculation is correct and eliminates the need to determine each individual factor.

      3. Regarding the significance of each factor, we have also written (and made available on our downloads page) a copy of our cost based OEE spreadsheet that uses cost drivers to determine which factor has the most significant effect from a cost perspective.

  9. November 7, 2012 at 11:12 am

    Dear sir, We are chemical industry in which we want to implement OEE concept. Can you please help how to implement OEE concept in chemical industry maintenance. Also in chemical industries, Quality of product is depend upon many parameters like raw material quality, process steps, adding times. Then how we calculate quality ? What will be formula for quality of equipment in our industry which is batch type. Please guide.

    • November 8, 2012 at 6:42 am

      Thank you for your request for assistance. I have reviewed your website and I am encouraged to note that your quality system is ISO-9001 registered. This suggests that an operating system exists where a frame work for implementing OEE can be established.

      As you may appreciate, OEE is premised on three key factors: Time, Rate, and First Time Through Quality. Regardless of the commodity type, the ideal rate of production through your process is a pre-requisite for OEE.

      The nature of your integration / implementation is best served offline to address your specific needs. I can be reached by e-mail at Redge@Versalytics.com

      Thank you and we look forward to working with you.

  10. Boobalan.s
    June 8, 2013 at 2:31 am

    hello sir,
    how to calculate the OEE for continuous production such as paper industries, please give it with example.

  11. December 28, 2013 at 7:21 am

    I have to deal with machine performances improvement everyday, I’m an automation engineer like many of you, so I developed a powerful tool for Android to get cycle time just tapping on a button, record every cycle time and export data. I hope you will find useful: https://play.google.com/store/apps/details?id=com.avafab.cycletime

    • December 28, 2013 at 9:28 am

      “Operator” variation is introduced with each button push and will be more significant with shorter cycle times. To minimize this error, I recommend adding a feature that allows the user to enter the number of parts produced or cycles completed over a measured period of time.

      For example, consider a clock hanging on the wall and measuring the movement of the second hand. Counting 10 movements then pushing the button is likely to provide a better “average” cycle time than averaging the time of 10 presses of the button. It is very doubtful that any of the individual “observed” lapsed times will equal 1 second. The accuracy of the cycle time is misleading since the operator error is likely more significant than the resolution presented.

      Although the intentions are good, we can’t recommend this app as presented. We note that similar functionality is provided on the BlackBerry’s clock app although the data send option is limited. Apple’s clock provides “stop watch” capabilities without the ability to export data.

      Thank you for visiting our site and we’ll keep watching for any future updates.

      • December 28, 2013 at 9:47 am

        I agree with you, we cannot avoid error introduced by user (operator). This app is just to have an idea of the speed of a machine. Your idea is very interesting, I will keep in mind for the next update! I usually design machines control software with an internal cycle time calculator that use a on/off signal as trigger (very fast), so it is very accurate, but sometimes we have machines in which the programmer doesn’t provided this calculator and the only way to get it is to use a stopwatch. Unfortunately common stopwatches doesn’t have an instant mean calculator and so I decided to built it by myself because mean is very significant in processes where each cycle time could be different, due to a series of causes. I usually take times looking at both machine internal counter on hmi screen and my app, my error is usually under 100ms that for processes of 10 seconds is acceptable. For next updates I will try to get a signal directly from the machine as trigger ( I don’t know exactly how), this could be an idea for improving accurance.

      • January 7, 2014 at 10:06 pm

        For automation, I’m accustomed to seeing the cycle time displayed on the HMI screen. After visiting your website, I can appreciate that you would be doing the same.

        It’s good to see comments from machine builders and programmers here.

        Thank you again for your comment.

  12. January 7, 2014 at 1:56 pm

    Hello Redge,
    I have a quick question regarding scrap parts and OEE. I see in the calculations that for each scrap part, it is assumed that there is a complete cycle loss. This may be the case in stamping presses where the quality is assessed after the machine operation.

    However, what if quality can be determined at different points in the cycle?
    For example, if a part is inspected prior to loading to the machine, and a defect is found, it can be rejected before cycling the machine. In this case, there is not a complete cycle loss. If this happens multiple times an hour, it can severely skew the calculations. ie. 20 scrap parts at only a 15 s loss each, compared to a complete cycle of say 60 s each.
    How would you deal with a situation like this?
    Thanks!
    Martin

    • January 7, 2014 at 9:57 pm

      Hello Martin, this is an excellent question and I agree with your synopsis. The objective of OEE is to capture and identify assignable causes for lost time. In this case I would treat this downtime as an availability loss with the added benefit of knowing the assignable cause (in-process quality defect).

      The quality factor is intended to measure “First Time Through Quality”. The operative word in this case is “through”. If a product is deemed defective prior to entering the process, it doesn’t make sense to reflect this against the quality factor.

      Thanks for visiting!

      • January 8, 2014 at 4:08 pm

        Thanks for the response. I hadn’t thought of adding it to the Availability calculation, but you are absolutely right. The machine is available to be used, but the operator is spending time looking for a good part to load into it. This is an availability loss.

        And your point about “first time through quality” is spot on, since lean thinking assumes all incoming stock to be good.

        I still don’t have an easy way to track the time loss here, since it is not a complete cycle, but what I have decided to do is assign an average “partial” cycle time to each defective part. The operator spends time dealing with the part, but it is not practical for me to get an exact time for each scrap part dealt with. I am working on a way to automate this time tracking, but for now I will use an average “scrap loss time” for each part and apply it to the Availability metric.
        Thanks again.

      • January 8, 2014 at 8:40 pm

        Martin, it sounds like you’ve got it and you’re definitely on the right track. I appreciate your original question and your feed back.

        Thank you again for visiting.

  13. Vinayak Kamath
    January 7, 2014 at 9:07 pm

    Redge :
    If the Tool change or Tool index time is incurred during the cycle time required to produce a part, the “down time” falls under Performance.
    The time required to complete one full production cycle (“button to button” or “start to start”) is the cycle time. Operations or sequences that occur during the cycle are all inclusive in the cycle time.
    If the tool change is required to produce a different part, the down time falls under Availability.
    Thank you for visiting!

    Hi I am Vinayak Kamath,

    I have a small query on the Tool change time. We have CNC Turning & Machining Centres. We need to index/replace the tool once it gets worn out. This happens many times during the production of a batch of identical parts. We consider this downtime under availability. Is this correct ?

    Thanks in advance.

  14. Juan Galan
    February 11, 2014 at 6:41 am

    I am looking for s simple formula that I can use to determine how many pieces a machine center can run in an hour by my take a simple stop watch cycle time study. I used to run production and we had time studies performed to establish the number of pieces required to run every hour.

    • February 12, 2014 at 11:58 pm

      Juan, you don’t provide much detail regarding your time study method, however, the following formulas may provide the answer you are looking for. We recommend measuring the time required to produce a reasonable quantity of parts (without disruption).

      There are two immediate approaches for a very simple study: 1) Measure the time required to produce “x” parts or, 2) Count the number of parts produced over a fixed period of time. We prefer the first method for processes with a clearly defined “finished” product or cycle.

      Parts per Hour = (“x” parts produced / “y” seconds of time) x (3600 seconds / hour)

      If you have determined the number of seconds required to produce a single part, as implied by your comment, then Parts per Hour = (3600 seconds per Hour) / (Seconds / Part).

      By way of example, if the cycle time is 10 seconds then,

      Parts per Hour = 3600 / 10 = 360

      For scheduling purposes, we strongly suggest using OEE to determine a realistic hourly run rate rather than a pure cycle time.

      Thank you for visiting.

      • Juan Galan
        February 13, 2014 at 7:28 am

        Very helpful. Thanks

  15. santossh jha
    April 30, 2014 at 2:51 am

    I am implementation of lean management system in aautomobile service centers and i am finding it very difficult to collect datas or i am not able to understand what to collect or the calculations that can be done relating to lean.few of which i know are takt time,vsm etc..can you plz help????

    • April 30, 2014 at 9:04 am

      Lean is the pursuit of perfection through the relentless elimination of waste. Data collection efforts should be focused to address areas where waste is prevalent in your operation. You may have to create metrics that meet your needs. Here are just a few examples that you may find helpful.

      Customer Focus: Customers want their cars repaired the right way and in the shortest time possible. So, it may be worth your while to measure Customer wait times, Time to Service (Plan versus Actual), Repeat Services for the same Symptoms / Causes.

      Lean is not a simple matter of measuring “something” or just “anything”. Why and what you measure must be meaningful to you, the company, and ultimately the customer. Your analysis of plan versus actual performance, “things gone wrong”, or “things gone right”, or other metrics that you create should resolve to a corrective action or actions that lead to improvements.

      Lean is not a prescriptive set of measurable data points, rather it is a culture that focuses on the elimination of waste through continuous improvements (daily).

      Thank you for your comment. We wish you the best of successes on your lean journey.

  16. Nayan Solanki
    June 10, 2014 at 5:45 am

    How can calculate the Ideal run rate???

  17. Ankit
    June 28, 2014 at 2:19 pm

    Sir i am appointed to access the OEE of the Carding Machine and i am confused about the Quality as it is difficult to determine the defected Meter run of the output.

    • July 25, 2014 at 8:51 pm

      Thank you for your inquiry, however, we don’t have enough information to provide you with a meaningful response. Please provide more detail regarding your process.

  18. Naresh Junagade
    July 15, 2014 at 11:59 am

    Tollo changeover is planned or unplanned ?

    • July 15, 2014 at 6:00 pm

      Tool change over is unplanned downtime – although we know it must occur at some point – and will affect your availability factor.

  1. March 20, 2009 at 4:30 pm
  2. November 29, 2009 at 4:26 pm
  3. September 19, 2010 at 4:41 am

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