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FLEXO Magazine : March 2011
Plants & Processes Attack Scrap!!! It can Make or Break a converter By robert Moran “Cost modeling is in demand,” says Darby. “Printers want new hires to understand it. They expect them to have ex- perimented with it, as well as be capable of analyzing data collected and drawing conclusions from it.” According to Darby, scrap comes in several forms: trim, makeready and print-run. Some scrap is routine and to be expected as a result of normal pressruns. Then there is what Darby calls “catastrophic scrap,” the result of mechanical mishaps and malfunctions that shred paper, spew ink or otherwise destroy materials on a grand scale. So much is at stake with this latter form of scrap that Darby issues a warn- ing whenever he has the chance: “Catastrophic scrap on one large order can eat up the year’s profit!” It’s a warning he repeated for the benefit of approximately 60 converters in a day-long workshop, “Scrap Reduction Through Scrap Prevention,” hosted by Nordmeccanica Group and its adhesives-making partner Henkel Corp. at Nordmec- canica’s North American headquarters in Edgewood, N.Y. in February. Darby, the session’s keynote speaker, maintains today as he did then that plants need to concentrate on different kinds of scrap depending on the type of runs they do. “Plants with short runs and frequent job changes need to concentrate on makeready scrap. Plants with long runs and few job changes need to concentrate on run scrap. All plants need to concen- trate on catastrophic sources of scrap.” Given estimates of press scrap at 5 percent to 9 percent of material and laminator scrap at 3 percent to 7 percent, it is clear to see that waste reduction is a sound strategy, accord- ing to Darby. He is not shy in offering strategies for reducing waste, and advises preparing for scrap according to category so as to avoid catastrophe. Trim ScrAp Trim scrap makes sense when graphic needs can be built into the print design. Examples include edge lines and register marks. Darby says trim scrap also proves valid when machine design minimizes web movement—starting with the unwind. Edge guides are important and can help the situa- tion, but they are far from the be-all and end-all. A simple routine maintenance program will minimize web movement and therefore assist in reducing trim scrap. The objective here is to keep rollers level. A supplier’s ability to consistently deliver straight edges on the substrate also weighs into the equation. mAkereAdy ScrAp Shorter machines, combined with quality tension controls, will consume less material as the press gets up to color and quality. Smaller adhesive reservoirs will also assist in achiev- ing lower lamination waste. Darby stresses appropriate process control. Accurate mixing and correct ratios will afford consistent laydown, and stabilizing process conditions such as nip and drying tempera- tures prior to start-up will produce the desired results more quickly. run ScrAp Limiting roll changes within roll splices and curtailing process upsets will promote optimal run conditions, says Darby. Proper surface treatments, coupled with appropriate tension controls, can reduce wrinkle and tear issues— including web breaks, which are counted among the root causes of catastrophic scrap. Good humidity controls are also essential. Faster cure and long potlife adhesives may play a role in reducing waste. Automatic splicing systems can decrease scrap, as can integrated electronic com- munication systems that monitor and report conditions on press and on laminator, which maintains materials balance. Modern, solvent- free lamination systems in development also show promise for improving the cost of scrap. Finally, as always, proper maintenance is paramount. n solvent-free lamination and adhesives with longer potlife were demonstrated at the nordmeccanica/Henkel sponsored workshop, “scrap reduction through scrap Prevention,” where clemson University’s Duncan Darby, PhD was the keynote speaker. www.flexography.org MarcH 2011 FLEXO 15 A dAy in The Life of A SoLvenT-free LAminATor In February, Nordmeccanica Group and Henkel Corp. partnered in presenting a one-day interactive workshop on scrap prevention op- portunities/solutions in the laminated flexible packaging industry. The event, held at Nordmeccanica’s North American headquarters, attracted between 50 and 60 flex- ible packaging converters. It featured a keynote address by Duncan Darby, PhD, of Clemson University ’s Center for Flexible Packaging; a live demonstration of solvent-free technology on Nordmeccanica’s Super Simplex laminator; and laboratory experiments involving adhesive potlife and fast curing technologies. The proceeding included the introduction of Henkel’s new laminating adhesive system (Liofol LA773-21/LA6016-21), which combines a curing agent with a two-component solvent-free poly- urethane adhesive. It was designed to enhance speed, safety and productivity and thereby im- prove a converter’s bottom line. Food packaging, health care, pharmaceutical and cosmetic ap- plications are targeted, and sustainability-related advantages are being promoted. Giancarlo caimmi, nordmeccanica Guido Kollbach, Henkel FLX_March11.indd 15 3/18/11 1:32 PM