Vapor Degreasing Medical Parts

Globe Tool and Manufacturing (Minneapolis, MN) prides itself on its close tolerances (+/- 0.0005 inch or less) on stamped or drawn metal parts produced from titanium, stainless steel or aluminum. The ability to perform such precise work on small, intricate, thin parts comes from the company's commitment to do virtually every operation in-house, from tool and die design to 100% hand inspection programs.

Globe's experienced and devoted work force is essential to its ability to design and produce all of its own manufacturing processes. The company has more than 200 experienced and dedicated employees - eight who have served the company for more than 40 years and about 40 who have worked there for more than 25 years.

These dedicated employees work in Globe's 85,000-ft2 plant, which houses a vast array of production and inspection equipment for final trimming and finishing. One of the most critical pieces of equipment within the plant is the large capacity solvent degreaser.

Since much of the company's work is medical related, including heart pacemaker cases, stringent quality measures must be maintained before the finished product can be shipped directly to its customers' stock. Heart pacemakers and their batteries are implanted in the human body. Therefore, they require the utmost in cleanliness and quality to ensure their reliability.

Various heart pacemaker parts after cleaning in the vapor degreasing system (pencil for scale).

Globe was able to achieve passable results by vapor spray degreasing with trichloroethylene in open top degreasers followed by aqueous cleaning and rinsing using vertical agitation in manually operated tanks plus an automated five tank system. However, drying was difficult and water spots were hard to eliminate.

As its production increased, Globe looked for a better cleaning method. The company worked with Finishing Equipment, a manufacturer of both aqueous and solvent cleaning equipment, to determine what would be the best cleaning system for the company. Tests confirmed that an ultrasonic trichloroethylene degreasing system, using rotation, multiple immersion, counter-current three-stage cleaning and condensate sprays would provide excellent results.

So, Globe installed a Finishing Equipment enclosed automated degreaser. The machine handles and cleans 10 trays of parts at one time, totaling about 600 trays in two shifts.

Various pacemaker parts require different cycles, and it is important that this cycle be done with certainty. To ensure the appropriate cleaning cycle is used, each part arrives at the machine with its assigned bar code. The bar code is fed into the computer system to instruct the machine on which cycle to operate. The computer control system also records the actual cycle that those parts receive and provides a permanent record.

The three-stage cycle in the machine provides virtually pure, distilled solvent in the third sump. The condensate final spray is pure distilled solvent with no non-volatile residue. The purity of solvent for cleaning and rinsing is essential due to the applications of the parts Globe produces.

Extensive testing of surface cleanliness was conducted by outside facilities. It was found that molecular cleanliness of the new system was improved compared to the previous system. "The improved and consistent level of cleanliness is the biggest factor," stated Kurt Carlson, Globe's director of facility maintenance. "Since installation of the vapor degreaser, other substantial benefits have been achieved as well. Production has increased about five times while our trichloroethylene use has been reduced 50%. Also 90% of our need for aqueous cleaning and subsequent extra effort for drying and removal of water residues has been eliminated."

The degreasing system is cooled by recirculated tower water, and no process water is used. This has reduced water costs and use as well as chemical and wastewater costs. Energy savings have resulted from reduced drying and water heating costs. "Now we are more environmentally friendly too," emphasized Mr. Carlson. "We have reduced our emissions by more than 50% and saved substantial labor per week. What once was one of our toughest and most undesirable operations at the plant has become a task that people enjoy doing."

And, what about the increased production need that started Globe's search for a new cleaning system? According to Tim Knapp, president, "We couldn't achieve the production that we now have without it."