Beyond the Obvious
Posted: November 30, 2011
This paper will explore some of the less obvious benefits of automatic
roll-change to narrow and mid-web printing operations.
There have been many case studies over the years that clearly substantiate the value of automatic roll change in narrow- and mid-web printing operations. Increased production and substrate waste reductions can be tracked to calculate an ROI analysis that can justify adding roll-change automation to printing presses. However, process improvements such as automation impact many other facets of your operation that are not readily measured or ordinarily considered as part of an ROI analysis. Collectively these secondary benefits represent a significant overall operational improvement.
Re-use of short rolls
Typically, partially used rolls containing less than 600 ft are considered scrap and are either recycled or sent to the landfill. In addition to wasting 600 ft of usable substrate, it costs additional money to dispose of these rolls. With automation these rolls can be used for cleanups, make-readies, or actual production runs. Waste is minimized and profits are maximized, and it's a pre-emptive way to be more environmentally responsible.
Buying on an exact program
A manual roll change can consume upwards of 300 feet or more of substrate plus ink which necessitates running a substantial overage to achieve the required sellable product. If a job has five roll changes, this could represent 1,500 feet or more of extra substrate and ink just to complete the job. With automation you only have the waste of a single make-ready and start-up, then virtually all of the subsequent rolls become sellable product. With roll-change automation you can limit your overage to as little as 3%. This savings is especially important when using expensive specialty substrates and inks.
Buying your substrate and ink on an exact program can be a powerful competitive advantage. It enables you to compete head-to-head with larger printers who maintain larger inventories of substrates and inks.
Manual roll change requires flagging the take-up rolls for edits to remove the unusable or substandard impressions. At best flagging is an inexact process that necessitates a careful off-line inspection. With roll-change automation the only edit required is at the first start-up. From that point on, it's continuous production, and each roll of product is good from beginning to end. Depending upon the number of roll changes in a job, automation could save you 20% to 30% in post production editing labor.
When you eliminate manual roll changes your web tension and print speed remain constant, images stabilize and color matches are maintained throughout the run. You will print optimum impressions from the beginning of the run to the end. There is no need to clean the plates during the print run because there is less chance of damaging solids buildup. Plates perform better and last longer.
Production at process speed
Most press operators exercise caution when it comes to manual roll changes. They would prefer to run the press slower and stop early to avoid having to re-web the press. Once you gain confidence in your automatic roll-change system, you're more comfortable running your press at the optimum process speed throughout the run. This results in a dramatic increase in the amount of product produced daily.
Consecutive numbering and barcoding
When using manual roll change on jobs requiring consecutive numbering and barcoding, it can take from 200 to 300 additional feet of substrate and ink to get everything matched up and in sequence again. This excessive waste is eliminated with automated roll change. You start the job and run it until it's finished-consecutive numbering and barcoding are maintained without interruptions.
No shaft handling
Depending on the press unwind, manual roll change may require handling heavy shafts or using external lifting systems. On an automatic roll changer with integrated lift and load, the spindle is guided into the core and a push of a button lifts and moves the roll into place. There is far less risk of operator injury and roll damage.
Running a press with non-stop roll change reduces energy costs. Recently, German label producer GEWA Etiketten GmbH performed a comparison test to measure the energy consumption of two presses running identical jobs involving two roll changes. The presses were a Gallus EM 340 six-color line and a Gallus RCS all-servo press fitted with eight stations. The first test measured the energy consumed while using manual roll change. The second test measured the energy consumed while using automatic roll change. For the second test, both presses were fitted with Martin Automatic MBSC unwind/splice and STR rewind units. The results were impressive, with an average of 23% less power per job! GEWA Etiketten projects that the splicer and rewind reduce their electricity consumption costs by €10,000 per year.
Extend the effective service life of UV bulbs
During manual roll changes, typical UV lamps are powered down to 20% to 25% of power and the exposure shutters are closed. These bulbs remain in a standby mode until the press starts back up to speed. While the cost of the energy consumed in this standby mode may not be a significant number, it is still consuming hours of the UV bulb's useful service life without producing product. With automatic roll change, the UV system is powered up and stays that way until the end of the run. There is no wasted energy in standby mode, and every hour of the useful bulb service life is dedicated to producing sellable product.
While the value of these less obvious benefits can vary from company to company, there is still value here that can help you create a competitive advantage. We invite you to look beyond the obvious and consider the benefits of automation in a more holistic way.