We are computing OEE taking all machines that we have inhouse together. Setting time, breakdown hrs., etc are taken for all machines together and a single OEE is computed. Is this right? or should we compute for only the contsraint machine.

I would be looking at each machine. You may have a process where you have recognized a 'constraint' machine and bought a second one or something like that. I don't know how you could do a single OEE without having data on each machine/operation/etc.

You could measure this in 2 ways. First, calculate OEE for individual machines. Then use these figures to calculate plant efficiency. This would highlight individual machine concerns. You could have a plant efficiency at 75% but this would not show that 2 machines could be running at different levels of efficiency. So in effect one machine could be carrying the other. I guess its all down to the amount of time and effort you can put into it each week/month and what data is available.

I have attached an example of the difference in machine efficiency and plant efficiency for you to review.

If you are using OEE to establish throughput, you are making it more difficult to identify bottle necks by lumping all equipment together.

What I have found to be very beneficial in the past has been to do a Value Stream Map before applying the OEE calculations. It identifies restraints and then you can put actual numbers on how the restraints are detrimental to the process.

Thanks everyone for the response.

Randy,
What does value stream map mean? Kindly explain.

For some reason there was no reply-
Try the folowing threads

Have any of you heard of a Value Stream Mapping (http://elsmar.com/Forums/showthread.php?t=10018)

VSM (Value Stream Mapping) - Use constraints or leave 'wide open'? (http://elsmar.com/Forums/showthread.php?t=11968)

Howard - Thanks for noticing and helping out!

Also see: OEE - Overall Equipment Effectiveness - Initials and Definition (http://elsmar.com/Forums/showthread.php?t=13138)

Here's another worksheet. Just enter the data in the yellow fields.

Wayne

Hi, is there any link explaining the theoretical correlations between availability, performance, quality - so when I improve e.g. availability, which impacts does this have on performance and quality? thanks a lot

Hi, is there any link explaining the theoretical correlations between availability, performance, quality - so when I improve e.g. availability, which impacts does this have on performance and quality? thanks a lot

That isn't the point ot OEE, to determine some correlation. The purpose of OEE is to:

1) Be used as a baseline for tracking progress
2) Identify the biggest area of opportunity

Just take it for what it is, as it isn't meant to be an exercise in stastical analysis.

Wayne

Hi

I ve been tasked with the job of measuring the OEE for the machines that we have. But the problem I have is we manufacture bespoke products and our machines make a number of different parts daily.. all varying in sizes and shapes and lot-sizes - lot-size could be even 1 sometimes.
Could anyone help me out and give me some idea on how I could best measure the OEE of these machines.

Thanks

Hi

I ve been tasked with the job of measuring the OEE for the machines that we have. But the problem I have is we manufacture bespoke products and our machines make a number of different parts daily.. all varying in sizes and shapes and lot-sizes - lot-size could be even 1 sometimes.
Could anyone help me out and give me some idea on how I could best measure the OEE of these machines.

Thanks

At a macro level, measure OEE like you would any other machine or part. You are just likely to have more set-up time that needs to be accounted for, and the consideration of different cycle times for different parts. Make sure you break it down into one shift increments for data collection and analysis. Trying to record an entire day if running three shifts and your likely to run into complications from lost information/data, changes in parts requirements or other variables throughout the day that makes it more difficult to track.

Something to heavily consider though, is that OEE isn't a one size fits all application, it is really meant to be used in conjunction with a larger system to identify and then address waste (machine downtime, poor cycle times, long set-ups, quality, etc.) present in the system. I wouldn't try to apply OEE to every piece of equipment, there really isn't any need, but instead use it as part of the larger strategy to identify root causes.

If you have more questions about a specific machine, it may help to download one of the OEE spreadsheets (http://elsmar.com/Forums/showpost.php?p=227772&postcount=10)available here and populate some of the basic information (shift length, breaks, etc). Create another worksheet inside the file and populate it with some of the information you have available by part number (keep the part number generic: A, B, C, etc.) so there is no issue of non-disclosures not being signed. Information that will be needed is set-up time, cycle time (from the start of one piece to the start of the next piece on the machine), first-pass yield, scheduled maintenance, and typical lot sizes (just make an educated guess for this exercise).

Do that and shoot me an e-mail with the information. I'll then re-post the spreadsheet with my comments.

Wayne

Oee is a weapon in your arsenal and it's a weapon designed to target equipment constraints.

I would calculate a site OEE based on the theoretical maximum output of the plant divided by actual output if i wanted to get a sense of overall manufacturing capability. I would then have a seperate OEE dashboard sat below for each asset.

However in this same scenario you must remember other metrics that sit above OEE - the April edition of Works Management (which can be downloaded for free from their website) but which i can't link to yet as a new user will give you some ideas. Being open one reason for me recommending this article is that i contributed to it but as it's written by the Director of Cranfield Best Factory please don't let that put you off as it's very useful!