Lately it seems I have been hearing a lot about overall equipment effectiveness (OEE) as an important metric in flexo printing. Plate and other vendors are touting the ability of their products and processes to enhance OEE and thus improve productivity, throughput and profitability. I was interested to see a study on this topic for digital presses, produced by John Zarwan of jzarwanpartners, and thought a summary of his findings would be of interest to our members.
What Is OEE?
So first, what do we mean by OEE?
Overall Equipment Effectiveness, or OEE, according to Zarwan’s report, is a performance indicator that quantifies the contributions of individual pieces of equipment within an operation. OEE combines three key production elements—equipment availability, performance, and quality—into a single metric. It measures the time equipment is fully productive, establishing a relationship between the maximum that can theoretically be produced and what is actually accomplished. This metric gives print providers a powerful tool that can be used to measure and improve operations.
From my own experience, I believe this to be a very important metric. While digital presses have greatly improved in reliability in the more than 25 years I have been following this market, I still hear from printing operations that sometimes it seems like the vendor’s technician is a staff member, they are there so often. This occurrence varies from vendor to vendor and press model to press model, but its frequency does affect press utilization and the ability to meet deadlines and revenue objectives. And it certainly should be a consideration when buying a digital press.
In his research, Zarwan examined the OEE of three digital presses: the Canon imagePRESS C10000VP, Ricoh Pro C9110, and Xerox® Color 1000i Press. He investigated their effectiveness in an operating environment. Are the presses available to print? Do the presses perform as promised? Do they meet expectations for quality? He collected relevant job information from a number of establishments running these presses and found that all three presses achieved high quality with very little waste, but as expected, differences in availability were mostly related to press breakdowns and the amount of time required to repair. He also found that the greatest amount of variation in availability had to do with press performance – how fast the machine printed compared to its rated speed. We know there are a lot of variables here, since vendors always say “up to” when quoting speed numbers!
And the Findings Were …
Zarwan found the OEE of all three presses to be acceptable, but with room for improvement. The figure below summarizes the results.
For a deeper understanding of this topic, I recommend that you read the full report, which goes into great detail about not only OEE but overall operational excellence, with lots of good advice. He states, “It should also be noted that OEE is the product of three factors, not a simple average of them. The OEE calculation therefore rewards consistency and punishes variability. For example, 10% x 90% = 9%, while 50% x 50% = 25%, even though the simple average of each is the same (50%). So if the cost of an error is high, then slowing down to achieve higher quality may be more important than maximizing performance or availability. This would likely result in a lower OEE, but that may be acceptable given business or customer requirements.”
In addition to using OEE as a decision criterion in buying a new press, Zarwan also points out that OEE can be used as a way of identifying and changing processes that negatively affect the operation, such as eliminating waste or shortening job setup and changeover. Of course, these factors may affect analog presses more than digital presses. He adds, “The ability to improve OEE through workflow changes for a digital press is more limited. A printer can try to schedule jobs with similar types of substrates, make sure the press is maintained and calibrated properly, or alter the standard number of proofs produced. RIPs can be optimized. Operators can be better trained. Beyond that, however, it basically comes down to equipment performance.” Which is why the study results are so interesting, especially if you are in the market for a new digital press.
To get your free copy of this important report, simply email Zarwan at [email protected]!