Seagate Technology is a leading manufacturer of hard disk drives.
Seagate Technology cleans laser-welding fixtures for disk drive suspensions. The fixtures collect carbon soils in their holes, which accurately navigate the laser. Prior to using the CO2 composite spray cleaning process, cleaning was accomplished by swabbing each hole with IPA and/or acetone.
Said Seagate Laser Welding Engineer David Buedorf, “Since the implementation of the system, we have achieved an estimated 2-3 percent yield improvement. Cleaning time has been reduced to one-fifth of the original time needed, and the improved fixture cleaning results in longer production runs between cleanings.”
“Today’s Forecast: It Looks like Snow”, Precision Cleaning, May 1999
Michael Mills, Senior Manager, SCAQMD, provided the following response to a request for clarification regarding CO2 cleaning technology and VOC regulations.
“Thank you for your letter regarding alternate cleaning technologies.”
“SCAQMD Rule 1171 refers to Solvent Cleaning Operations. Definition on page 1171-5 states “VOLATILE ORGANIC COMPOUND (VOC) is any chemical compound which contains the element carbon, excluding methane, carbon monoxide, carbon dioxide, carbonic acid, metallic carbides or carbonates, ammonium carbonate, and exempt compounds. Our conclusion is that since carbon dioxide is by definition neither a VOC nor an air contaminant, the equipment and/or process is exempt from CAQMD permits pursuant to Rules 201 and 203.”
Michael D. Mills
South Coast Air Quality Management District (California)
Letter to Deflex Corporation, April 7, 1994
Bill Irving, Program Analyst, USEPA, provided the following response to a request for clarification regarding CO2 cleaning technology and Global Warming Gas regulations.
“Thank you for your interest in the issue of global climate change.”
“Based on your description of how carbon dioxide is used in your industry, I agree that there is no net effect on carbon dioxide emissions to the atmosphere. This CO2 would have been emitted into the atmosphere from its original source had it not been captured by your suppliers.”
U.S. Environmental Protection Agency
Facsimile to Deflex Corporation, November 25, 1997
In early 1995, a program was initiated by the Environmental Protection Agency to investigate new and innovative surface cleaning and degreasing technologies as alternatives to ozone-depleting compounds including 1,1,1- trichloroethane (TCA), methylene chloride, and Freon 113 [1,1,2-trichloro-1,2,2-trifluoroethane, chlorofluorocarbon (CFC)-113]. One promising candidate identified during the investigation was liquid carbon dioxide (LCO2). The United States Air Force at the Warner Robins Air Logistics Center (WR-ALC), Robins AFB, GA, was requested to participate in the demonstration and served as the demonstration site. The WR-ALC uses several surface cleaning processes at the facility during aircraft systems maintenance. These processes generate a broad range of air, water and solid waste environmental contaminants. The volume of these wastes could be reduced by the use of LCO2 cleaning.
LCO2 is of interest as a potential solvent degreasing substitute largely because of what it is not. First of all, it is not an ozone-depleting compound (ODC). Therefore, it does not present a threat to the earth’s ozone layer as found with typical chlorofluorocarbon (CFC) solvents. It is nonflammable and has low toxicity. Thus, is does not present a safety hazard when used properly. Finally, LCO2 is not expensive when compared to CFCs and equivalent substitutes. This is important to its viability as an industrial surface cleaning and degreasing solvent.
The objective of the project was to demonstrate the viability and efficiency of the LCO2 cleaning as an alternative to current cleaning and degreasing technologies. The study was designed to show that LCO2 cleaning, when properly integrated into the manufacturing process, could remove various organic and solid contaminants typically removed during vapor degreasing with ozone-depleting solvents.
The LCO2 process was shown to be equivalent to TCA in performance for cleaning the parts evaluated during this project. Successful introduction of the LCO2 process into a facility will require a detailed knowledge of the contaminant to be removed, the desired surface cleanliness level and the configuration of the part. This knowledge will permit the LCO2 process to be effectively implemented into a production operation to achieve the required cleanliness level, with an optimal ROI.
“Demonstration of Liquid CO2 as an Alternative for Metal Parts Cleaning”, Precision Cleaning, Sept 1996
“Demonstration of Liquid Carbon Dioxide Process for Cleaning Metal Parts”, USEPA Report, November 1996