complexity of the parts, as well as their critical tolerances. In many rebuilding facilities, transmissions are cleaned in aqueous spray washers followed by manual scrubbing in a solvent tank. The latter process is labor intensive, and uses cleaning chemicals (solvents) that can be harmful to workers and the environment. In this article, the benefits of using an alternate cleaning method - ultrasonic cleaning - will be described and evaluated. The results of this research were obtained from the installation of an ultrasonic cleaning system at an actual transmission rebuilding facility, Dial Transmission of Merrick, New York, located in western Long-Island. Dial Transmission rebuilds both manual and automatic transmissions, foreign and domestic, for automobiles and light trucks. This project was conducted by the Center for Integrated Manufacturing Studies (CIMS) at Rochester Institute of Technology (RIT). CIMS provides technology and workforce development solutions that strengthen its industrial clients' ability to compete in the global marketplace, and delivers results in the form of direct assistance, technology transfer and research and development. Funding for this project was provided by New York State Energy Research and Development Authority (NYSERDA). NYSERDA's focus is on research into energy supply and efficiency, as well as energy-related environmental issues. Both CIMS and NYSERDA seek to publicize the results of this project, so as to make other companies aware of the large benefits to be obtained frm- implementation of alternative, cost-effective cleaning technologies. Conventional Process The typical transmission cleaning process is a lengthy procedure. For small to mid-size transmission rebuilding companies, the transmission is fully disassembled after the core is received. Following disassembly, the parts are separated into various categories such as housings, input drums, planetary gears, bearings and valve plates. Bearings, planetary gears, valve plates and input drums are often cleaned in a solvent parts washer, and then blown dry with compressed air. In some cases, input drums cleaned in the solvents parts washer are also cleaned in an aqueous spray washer with transmission housings. If parts are not cleaned satisfactorily in the aqueous spray washer, they may be rewashed in that process, or
~~ -a Special Focus cleaned again in the solvents parts washer. CIMS evaluated conventional transmission cleaning processes at three companies and noted the following common problems: Varnish coated on the inside of input drums is difficult to remove. Manual scrubbing processes in solvent parts washers are laborintensive, particularly for valve bodies. Use of compressed air to dry parts is labor-intensive, and solvent droplets become airborne, compromising indoor air quality. Valve bodies must be cleaned thoroughly to prevent degradation of pistons and seals from small particles, but this is difficult to attain in conventional cleaning processes due to their complexity. Planetary gears cannot be washed in aqueous spray washers due to -- pntentbl rust problems from trapped water in needle bearings. Removal of contaminants from complex parts often requires pretreatment with toxic cleaners containing perchloroethylene, methanol, xylene, ethylbenzene and monochlorotoluene, all of which are hazardous. Some solvents from solvents parts washers pose safety hazards to workers, and can be more risky to dispose of than aqueous detergent chemistries. Figure 1. Demonstration at Dial Transmission -January 28,2003. Figure 2. Transmission parts before cleaning in ultrasonic parts washer. 1 i One of CIMS objectives for this project was to identify and implement an alternative cleaning system that would resolve these issues, while improving product quality at lower cost. Identification of Alternative Processes CIMS targeted replacement of the solvents parts washer with a safer and less labor-intensive cleaning process. Ideally, the alternative process should avoid the use of toxic cleaners and compressed air for drying parts. In addition, the alternative process should be capable of cleaning complex parts quickly and with aqueous-based chemistries. Several combinations of cleaning technologies were evaluated in CIMS Surface Cleaning Technology Evaluation Facility, with cleaning trials conducted on production-scale equipment, and forecasting of cleaning efficiency with computer models developed at CIMS for this purpose. Several types of cleaning equipment were evaluated during cleaning trials, including ultrasonic cleaning, enzymatic cleaning, highpressure aqueous washing and multi-media abrasive blasting. Cleaning efficacy was assessed for each trial, and cleaning statistics were entered into a database for subsequent retrieval and analysis. CIMS also estimated cleaning performance with the use of a computer s-4 Special Focus www.cleantechcentral.com
Special Focus Figure 3. Transmission parts after cleaning in ultrasonic parts washer. model developed at CIMS [see the October 2002 issue of CleanTech magazine]. This model, which was constructed from a database of hundreds of cleaning trials conducted at CIMS, produces a ranked list of feasible cleaning options based on cleaning requirements, substrates, contaminants loadings, part mass and volume, and several economic variables such as labor rates and resource costs, including power, heat, water, cleaning chemistries, et cetera. The system will list recommended cleaning technologies as well as specific chemistries, concentrations, and temperatures to be used in their operation. For both analytical methods (cleaning trials and computer modeling), ultrasonic cleaning was indicated as a feasible technology The line of cleaning equipment Equipment with the features you need to get the resufts you want: 0 Filtration 0 Waste fluid recycling 0 Oil removal 0 Programmable controllers 0 Agitation Automated material handling -- 0 Multiple frequency ultrasonics Our cleaning experts will... Analyze your application (FREE application testing in our lab) Specify an optimal cleaning process Identify effective chemistry Design, manufacture, install, and support your cleaning equipment v \BILACKSTONE*NEV \ ULTRASONICS ~_ Your Global Partner In Cleaning Innovation Phone: (716) 665-2340 * Fax: (716) 665-2480 Email: info@blackstone-neyxom Toll-free: (800) 766-6606 (www. blackstone-ney.com Circle 9 or request info instantly at www.cleantechcentral.com Special Focus www.cleantechcentral.com s-5
Special Focus meeting stated cleaning criteria. The particular ultrasonic cleaning system tested in CIMS' facility was a GMP 3523 non-agitating ultrasonic cleaning system manufactured by Blackstone-Ney Corporation. This equipment delivers 2,000 watts of ultrasonic power in a reservoir of 40 gallons, or a power density of 50 watts per gallon, and uses a 15% concentration of aqueous-based chemistries manufactured by Brulin Corporation at a temperature of 165 degrees F. Dial Transmission Installation Based on the results of the cleaning trials and computer modeling, Dial Transmission agreed to install the same Blackstone-NEY ultrasonic cleaning system tested at CIMS, and operate the system under the same conditions utilized during testing. The equipment was purchased from Global Sonics of Danville, Indiana, a s u p p l i ~ ~ oultrasmriic f eq~~$~~~entand cleaning chemistries. The benefits of ultrasonic cleaning became apparent to technicians at Dial Transmission immediately after the equipment was installed. The most noticeable difference was a reduction in the use of compressed air. Because parts cleaned at 165" F will flash dry upon removal from the cleaning bath, there is no need to dry the parts with compressed air. As a result, compressed air usage dropped 67 percent, with significant concomitant improvements in indoor air quality. In addition, labor costs were reduced as a drying step was eliminated. Because ultrasonic cleaning is particularly effective when used to clean parts with complex geometries, blind holes and narrow chambers, usage of solvents parts washers was reduced from eight hours per day to less than one hour per day, with corresponding reductions in labor costs. The total time spent on manual scrubbing processs-6 Special Focus www.cleantechcentral.com ~
Special Focus es per transmission was reduced throughput rate, the system will pay other manufacturing companies on from 90 minutes to 15 minutes. A for itself in 12 weeks, an outstanding January 28,2003. Twenty-three peosingle batch of small parts in the investment by any criteria. ple from 11 companies attended this Blackstone-NEY parts washer can Dial Transmission concluded their event. Participants at the demonbe cleaned in less than four minutes, participation in this project by agree- stration included automotive parts eliminating a production bottleneck. ing to demonstrate the technology to rebuilders, equipment/chemistry The particular solvents parts, washers used by Dial Transmission consisted of a sink and solvent pump, with a distillation unit that would run at night to purify contaminated solvent. Because the load on the solvents parts washers was significantly reduced, it was no longer necessary to perform a distillation on the cleaning fluid each day As a result, less energy was consumed, and less solvent was used and disposed of in the process. In addition, consumption of toxic cleaning sprays such as perchloroethylene and methanol was AUSpray.com is the new quality, competitively almost completely eliminated. Finally, product quality was improved, due to the superior performance of the ultrasonics parts washer in cleaning complex parts. Economic Performance At a labor rate of $20 per hour (not Dial Transmission's actual labor rate), the cost of cleaning a single transmission is reduced by $33.83. This includes the cost of energy, labor, cleaning chemistries, water and waste disposal. Even though the ultrasonic tank consumes a significant amount of energy for heating the cleaning bath and in using ultrasonic energy to clean parts, this is more than offset by reductions in use of compressed air and distillation frequencies in the solvents parts washers. As a result, energy consumption per transmission is reduced from 5.53 KWH to 5.44 KWH. Finally, reductions in labor of over two hours per transmission were obtained for the alternative cleaning process. The installed cost of the equipment is slightly more than $10,000. At Dial Transmission's present %&us today and discmx a new source for spray nozzles and acasmries or email us at Tecbinfo@All3pray.com Circle IO or request info instantly at www.cleantechcentral.com Special Focus www.cleantechcentral.com s-7
Special Focus manufacturers and distributors, and technology transfer organizations. Dial Transmission explained how parts were cleaned prior to implementation of the equipment, and how product quality was improved while reducing cleaning costs with installation of the new system. These demonstrations are very effective tools for propagating technology, as participants can observe parts being cleaned in an unbiased, no-pressure, actual production environment. Figure 4. Experimental testing for ultrasonics parts washer conducted at CIMS. Conclusion Ultrasonic cleaning is shown to be an effective means of cleaning certain transmission parts. It improves product quality while reducing operating expenses for cleaning, uses less energy and creates less environmental impact while improving worker safety. With a payback period of 12 weeks, it is clearly a worthwhile investment, for this application. Since this demonstration was conducted, CIMS has also installed washwater recycling equipment at Dial Transmission to extend the life of the cleaning bath used in the ultrasonic parts washer. This technology was also shown to be quite effective, and is the subject of another program being studied by CIMS to assist manufacturing and remanufacturing companies in improving productivity and product quality while reducing energy consumprion, o p e " g p impacts to the environment. CIMS will be reporting the findings of this and other programs in a subsequent articles in CleanTech magazine. Editor's Note NYSERDA has not reviewed the information contained herein, and the opinions expressed in this report do not necessarily reflect those of NYSERDA or the State of New York. About the Author Newton B. Green 11 is a senior staff engineer and Clean Technologies Team Leader at CIMS. The Clean Technologies Team works with remanufacturing companies and OEMs in suyface cleaning and finishing, washwater recycling, waste minimization, pollution prevention, and energy conservation. Mr. Green has over 19 years of experience in consulting engineering, project management and pollution prevention. He is a registered Professional Engineer, board-certified environmental engineer, and Project Management Professional. He may be reached by e-mail at reman@cims.rit.edu. Circle I I or request info instantly at www.cleantechcentral.com S-8 Special Focus www.cleantechcentral.com