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FLEXO Magazine : November 2008
TECHNOLOGIES & TECHNIQUES when cleaning by hand, while only 17 percent of those surveyed indicated that they use organic or green cleaning solutions.”1 In addition to being time consuming, traditional cleaning methods (sanding, scraping and scrubbing and dissolving con- taminants with alkaline-based and acidic chemicals) put the equipment and the cleaning crew at risk. Over time, the harsh chemicals can damage the press components, and they are also unsafe to work with due to their toxicity. In addition, following the cleaning process, any towels and waste from the solvents must also be collected as toxic waste resulting in additional sec- ondary waste disposal and treatment costs. Other methods, such as pressure blast cleaning systems that use soda or beads, can be very abrasive, may damage press components and leave behind secondary waste that also must be disposed of. In many cases, solvent-based cleaning and soda and bead blast- ing require the equipment to be disassembled and transported to special cleaning areas. Any time that equipment is disassembled and moved, it is at risk of being damaged. Once reassembled, the equipment must be properly aligned to ensure product quality. In addition, the prolonged shut-downs cost companies valuable production time while labor for disassembly, transport, cleaning, drying, reassembly and calibration is becoming increasingly more expensive. LEAPS AND BOUNDS Chemicals and scraping have been the standard methods for cleaning press components for years. Government agencies and environmental advocates, however, continue to put pressure on all industries to reduce the amount of chemicals because of their impact on the environment and the potential harm to people. Printers, like manufacturers, need a safe, user-friendly cleaning solution that is also effective, economical and environmentally responsible. Among the solutions being evaluated and used by printers today is a process that originated in the 1970s as a technology for the aerospace industry. Dry ice blast cleaning was developed originally to provide a cleaning solution that could eliminate the chemical cleaners being used to strip paint from airplanes. The Before dry ice blasting. After dry ice blasting. technology included a unit that produced the dry ice media and then fed the media directly into the blasting unit. The first gen- eration dry ice blast cleaning system, developed in Cincinnati, OH, was the size of a tractor trailer and could produce more than 450 lbs (204 kg) of dry ice an hour. Like the computer industry, the technology behind dry ice blasting and production has gone through a miniaturization pro- cess. Today, there are dry ice blasting machines that are powerful enough to clean the largest tire molds, yet delicate enough to clean electrical components and microchip manufacturing equip- ment. Moreover, some of the machines can now fit in the back of a Mini Cooper. In addition to miniaturization, market studies showed that the typical application for dry ice blasting does not require a fully integrated system with such a high level of sophis- tication. As a result, the technology has moved away from the large integrated system in favor of distinct blasting and dry ice production machines. The portability and simplicity of today’s dry ice blast cleaning systems have made the solution viable for virtu- ally any industry. Dry ice blast cleaning is similar in concept to sand or bead blasting. However, dry ice blast cleaning uses recycled Carbon Dioxide (CO2 ), in the form of solid dry ice particles that are ac- celerated through high-velocity nozzles to impinge upon the surface being cleaned. Dry ice particles have a temperature of -109 degrees Fahrenheit. As a result, the combination of the kinetic and thermal shock effects breaks the bond between the residue and the surface. The residue falls away from the surface and is easily disposed of. The dry ice particles sublimate upon impact, eliminating the added cost and inconvenience of sec- ondary waste treatment and disposal, as well as any downstream contamination. Dry ice blast cleaning is a metered and non-abrasive process, meaning that end-users can control the level of the blasting and it won’t wear away the surface being cleaned. The process elimi- nates the need for solvents and hand tools as it dissolves con- taminants and blasts them away. The Cold Jet study reported that more than 69 percent of manufacturing decision makers surveyed indicated that they have to completely shut down production to clean their equipment while 41 percent have to dis- mantle and move equipment to another loca- tion to be cleaned.2 Since most dry ice blast machines are portable, they can be wheeled to the print- ing presses and clean the equipment while it is still in place. With no secondary waste and the ability to clean machines while they are hot and online, dry ice blasting contributes to improvements in productivity while reducing the risk of equipment damage and the need to disassemble machines and relocate parts for cleaning. Printers that adhere to the principles of Lean Manufacturing and Total Preventative Maintenance are embracing dry ice blasting because of its ability to help reduce prolonged shutdown times. 48 F LEXO NOVEMB E R 20 0 8 www. f l e x o g r a p h y. o r g