A Need for Speed? Short Runs Put an Emphasis on Changeovers

By Mario Mucciacciaro

Time is money. It’s a fact all flexographic printers/converters understand. The faster a job can be set up, run to completion and broken down in preparation for the next job, the more jobs that can be run. Every minute that a press isn’t running is money lost.

In today’s flexible packaging market, printers throw around the words “high speed” in reference to wide web flexo presses. But what is “high speeds”? And more importantly, how critical is “speed,” in the strictest sense of the word? The answer to both questions is, “It depends.”
The large majority of wide web presses in operation today are running at anywhere from 900fpm to 1,200fpm. Those are considered typical working speeds. Some printers will run at 1,500fpm, which is considered pushing the limits. When mostflexo printers are thinking about high speed presses, they are referring to those that can run 1,800fpm and up. That’s because, at these speeds, you are in a different ballpark.

  • Most wide web printers run between 900fpm and 1,200fpm.
  • Speeds above 1,800fpm only make sense on long runs.
  • With shorter runs, changeover times are more critical than actual run speeds.

Once you start looking to 1,800fpm or more, many flexo printers have to consider buying a new press, and need to make adjustments in prepress, etc.

Fast Facts Technically, there is no limit to the speed that a gearless flexo press can run. The servo motors that drive the mandrelsare not limited by anything, per se. Heck, you can adjust the top speed of your car’s engine to go 200mph. The problem is there are components beyond the motor that have to be able to run at such speeds. The same thing applies in flexo.

Getting to high speeds requires more than just the press. You are talking about ink transfer, drying, prepress, and other factors. So the printer needs to be well equipped to run at high speeds. Ink is going to be a major player—what properties must the ink have to get it from the anilox to the plate and then the substrate at such speeds. On top of that, how do you dry the ink on that substrate? The anilox rolls have to have the right volume, and be able to release the ink without sending it everywhere. Not to mention, mandrels and carriers have to be suitable to run that fast; TIR tolerances have to be much tighter. Only when all these are in place, can a printer run at 2,400fpm or higher.

The Long and Short of It There are three parameters that have the greatest affect on production: changeover time, waste generated from startup,

and speed of the press. One of these alone does not give a competitive edge. Today, many printers are looking for machines that reduce waste and facilitate faster startup. Truth be told, many of them are forsaking speed.

The reason is, in today’s flexible packaging industry, the portion of long runs to short runs is increasing in favor of the latter. Customers will not accept stock inventory, and packaging is being constantly redesigned, even for legacy brands. As such, many printers are running at lengths of 10,000 to 20,000 feet. With a 10,000 foot job, there is too much waste generated by running at a high speed, not to mention roller handling is another concern. You are better off having a faster changeover.

Today, most people with geared presses are changing over eight colors in three hours! With gearless technology and the introduction of sleeve presses, it’s happening in as little as 20 minutes. Most eight color servo presses can be changed over in 20 to 30 minutes. With automatic impression setting, this time can be reduced even further. Most wide web press manufacturers have some version of this technology. This also reduces waste—bringing it down to as little as 150 feet per job.

Not to mention, there’s also automatic wash-up systems. Wide web anilox rolls are heavy, even if they are sleeved. To not have to remove each one and clean it by hand after every job saves a tremendous amount of time. Lastly, there’s also a human factor that can be controlled and fine tuned for even faster changeovers, by establishing a pit crew mentality and adopting elements of a Lean or SMED (single minute exchange of dies) workflow.
High speed matters the most when it comes to long run lengths. When you are producing orders of 1 million units, orthe work load duration spans over two working shifts, then speed will have a massive impact on profitability. But when daily changeovers occur six to eight times a day, the speed that matters most is in changeover.