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OEE for Varying Cycle Times

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  • #55789

    Robert
    Guest

    Is there a form of oee or similar metric for equipment with varying cycle times?

    For example, if you make eyeglass lenses on an automated cnc type machine, how could you calculate oee? The speed of the machine depends on the material and the prescription, but there’s no way to batch jobs with those attributes to do a weighted cycle time. Jobs are processed as they come in. First in first out.

    What would any of you recommend as a better metric/s for this type of situation?

    Thanks,
    Rob

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    #201732

    Chris Seider
    Participant

    One approach is to accept the fastest cycle time as the top technical speed INDEPENDENT of the material being processed. Losses are then bucketed and “known” losses are accounted for the material impact.

    I’ve seen that approach and it’s clean because it does impact capacity also since OEE does impact proven capacity questions.

    Others will say calculate performance losses based on different technical speeds but then no one will EVER (most likely) ask how to improve speeds of slower running materials.

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    #201738

    Robert
    Guest

    Thanks Chris, that makes a lot of sense.

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    #201739

    Mike Chambers
    Participant

    Chris is right, especially for a manual system. Keep in mind the purpose of OEE is to drive improvement. To Chris’ point, if the resolution and ease of use is an issue, there will be limited improvement.

    An automatic system that archives historical performance can overcome this. We use a real-time system that is based in MS Excel/Office that has this capability. You could then rank and attack your “bottom 10” bad actors for a given time period.

    Yet another option is to not get bogged down in the details and instead work using a duration that is long enough to wipe out the effects of mix. That may be an hour, shift or day … whatever makes sense.

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    #201740

    Chris Seider
    Participant

    @MikeC
    Nice to have those automated gathering systems to get to analysis! Neat.

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    #201742

    Robert
    Guest

    Mike,

    “An automatic system that archives historical performance can overcome this. We use a real-time system that is based in MS Excel/Office that has this capability.”

    Do you know how your system archives this data? Is it some type of proprietary interface that’s part of the machinery? An after market sensor setup?

    I’m also software developer and I’m curious how this is done.

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    #201743

    Chris Seider
    Participant

    @rmnrdi
    Check this site out. http://www.debtechsystems.com/default.htm
    I’ve used them to design with me a system to track losses for a fully manual system with no signals from the field. It’s very easy for operators to use.

    They can get with you on the details. I have no financial connection with this organization and get no compensation. Mention my name and they will know what they helped us implement.

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    #201744

    Mike Chambers
    Participant

    Robert,

    “Do you know how your system archives this data? Is it some type of proprietary interface that’s part of the machinery? An after market sensor setup?”

    The system (known as Real-Time Production Efficiency Monitoring) archives the data by default at midnight on the last day of the month. The norm is to accumulate it in shared network storage where it can be analyzed by anyone.

    No, the interface is not proprietary. It’s MS Office-based and readily links to PLC’s, data loggers, and Arduino-type devices.

    The sensors can be after market or OEM.

    Let me say I do have a financial interest in this. My company is the one that developed the system back in 2009. Having said that, we have yet to find a more economical way of monitoring a manufacturing process in real-time. It’s incredibly flexible and MS Office can usually be supported in-house. Our book available at Amazon or eBay provides details.

    Given my involvement and the fact I don’t want to hijack this thread, I’m reluctant to post additional details here. If there’s interest, I will post screen shots and answer additional questions in a separate thread.

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    #201745

    Mike Chambers
    Participant

    Oooops … one of the posted links have changed. The correct link for Amazon can be found here.

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    #201749

    Robert
    Guest

    Thanks guys. I’ll be sure to check out the resources.

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