Dry ice cleaning

Medical device manufacturers face challenges in cleaning and maintaining equipment, as well as deburring or deflashing products. Many parts produced are small, and equipment is finely detailed and expensive. Residue build-up in small mold cavities and on expensive tooling used during production can harm the quality of the end product. Build-up can push parts out of tolerances, elevating scrap rates, and could eventually clog mold cavities, impeding tooling performance. Residue can also prevent the imprinting of small, critical details, such as measuring scales on syringes.

Because of the small size of mold cavities – and in many cases, the delicate nature of the equipment – cleaning is typically labor intensive. The high tolerances on the parts also demand stringent quality controls – the cleaning process must equal the manufacturing process in terms of quality and diligence – so manufacturers try a variety of methods (See sidebar on page 20).

Improving quality

When grinding needles or laser-etching holes and slots, burrs can form that require deburring. Clogging reduces airflow and can damage the parts, which then must be scrapped.

Traditional cleaning methods – such as sandblasting, chemical solvents, and manual scraping, chipping, drilling, and scrubbing with brushes – are time consuming, with cleaning a single mold taking an hour or more, including equipment disassembly and reassembly. In addition to being physically demanding on maintenance workers, these cleaning methods can damage the equipment and are not completely reliable.

Benefits, safety, savings

CO2 recycled into dry ice pellets or pieces can be accelerated at supersonic speeds to delicately remove residue from parts and equipment, reducing cleaning time by as much as 75%. The process is helping medical device manufacturers improve quality, increase production, prolong equipment life, improve worker safety, reduce costs, and support environmental initiatives.

Unlike abrasive cleaning methods, the combination of the kinetic and thermal gradient effects breaks the bond between the residue and the surface. When the dry ice hits the surface, it sublimates, (transitions from solid to gas with no liquid step), eliminating any secondary waste. After sublimation, miniscule contaminants fall to the floor or are captured in a high-efficiency particulate air (HEPA) filter.

Since dry ice blasting cleans without abrasive or corrosive solvents, equipment lasts longer. Unlike sandblasting, no media can get trapped in tight spaces within the equipment to cause damage.

The environmentally responsible cleaning process produces no secondary waste, reducing the possibility of downstream contamination. Workers do not face exposure to harmful solvents or work with extremely hot equipment, and there is no repetitive motion that can cause injury to workers.

Labor costs for cleaning delicate molds are reduced as cleaning can be done by one person with a single system.

Benefits

Pushing back scheduled cleaning to meet production demands can have both short- and long-term implications for manufacturers. Unless molds and equipment are consistently and properly maintained, production and quality may suffer in the short-term, while the equipment life may be cut short or plagued with constant repair. Dry ice blast cleaning enables manufacturers to clean faster and more often, helping consistently produce high quality results while also extending the life of equipment. Cleaning quickly enables manufacturers to get back to production and growing the bottom line.

Cold Jet LLC

www.coldjet.com