Grantee Research Project Results
Final Report: Low-Cost Machining Without Cutting Fluids
EPA Contract Number: 68D02016Title: Low-Cost Machining Without Cutting Fluids
Investigators: Rozzi, Jay C.
Small Business: Creare Incorporated
EPA Contact: Richards, April
Phase: I
Project Period: April 1, 2002 through September 1, 2002
Project Amount: $69,891
RFA: Small Business Innovation Research (SBIR) - Phase I (2002) RFA Text | Recipients Lists
Research Category: SBIR - Pollution Prevention , Pollution Prevention/Sustainable Development , Small Business Innovation Research (SBIR)
Description:
Cutting fluids have been used in machining processes for many years to increase lubricity by spraying the coolant into the machining zone directly on the cutting tool and the part. This has the effect of decreasing the friction between the chip and the tool, which decreases the tool temperature, increases tool life, and improves the part's quality. These benefits come with significant costs, however. In high-volume machining operations, at least 16 percent of the machining cost is associated with the procurement, maintenance, and disposal of cutting fluids. This cost does not account for the health risks to which workers are exposed when using these fluids. Contact with fluids or their mists can cause maladies such as dermatitis and respiratory diseases, and some additives in cutting fluids may be carcinogenic. Because of these problems, the high-volume machining industry has, in recent years, moved toward dry cutting to reduce or eliminate the use of cutting fluids. Although it eliminates cutting fluids, this option increases fossil fuel consumption and energy costs because larger, more powerful machines are required to process less lubricious material. This option also increases the per-part costs by consuming more cutting tools and more machining time. The dry cutting option is not feasible for relatively small shop sites, where the capital for new machines is not available.
Creare Incorporated's solution is to cool the cutting tool indirectly using an inert working fluid. This novel, low-cost system eliminates the need for machining coolants. Tests have shown that the Creare Cutting-Tool Cooling System (CUTS) achieves performance that exceeds cutting fluids and suffers none of the drawbacks associated with machining coolants. The CUTS is a prevention-oriented solution to the environmental and occupational health problems posed by cutting fluids. This technology is an excellent way for small and large machine shops to eliminate the use of environmentally unfriendly, potentially toxic, and costly cutting fluids. In addition, the CUTS uses flow rates of the working fluid that are several orders of magnitude smaller than direct cooling methods, such as the jet impingement of machining coolant or liquid nitrogen (Zhao Z, Hong SY. Cooling strategies for cryogenic machining from a materials viewpoint, Journal of Materials Engineering and Performance 1992;1(5):669-678; Paul S, Dhar NR, Chattopadhyay AB. Beneficial effects of cryogenic cooling over dry and wet machining on tool wear and surface finish in turning AISI 1060 steel. Journal of Materials Processing Technology 2001;116:44-8). Creare Incorporated's system offers the unique opportunity to decrease the environmental impact of machining operations while simultaneously decreasing production costs through increased tool life and lower energy consumption. This combination increases the commercial potential of the technology.
The system has several environmental and cost benefits:
- Zero Toxic Emissions. The use of an inert working fluid by the CUTS
is a prevention-oriented, pollution control approach that eliminates the toxic
emissions from machining processes associated with cutting fluids. The system
produces only inert gas at flow rates 250 times less than conventional direct
cooling methods. The gas can be easily and safely vented to the environment.
- Low Cost. Detailed cost studies demonstrated that the CUTS represents
the lowest cost option for machining when compared to dry cutting and jet
cooling using a synthetic coolant. The costs of procurement, maintenance,
cleaning, and disposal of cutting fluids will be eliminated. Implementation
of the CUTS requires no significant modifications to the machine tool. Thus,
the system can be easily and affordably implemented by small and large machining
centers alike.
- Very Low-Flow Rate of Working Fluid. Because of its high heat transfer
capability, the CUTS requires only 10 L of inert working fluid to increase
the cutting tool life by twofold or more compared to an equivalent conventional
machining operation using 2,000 L of synthetic coolant. These coolant volumes
are needed for one machine operating constantly over an 8-hour shift.
- All the Benefits of Dry Cutting. One of the primary benefits of dry cutting is that the chips and the finished part exit the machine clean, dry, and ready for the next production step. Using the CUTS, the same benefits are realized at a lower cost.
Summary/Accomplishments (Outputs/Outcomes):
The proof-of-concept testing during this project met or exceeded all of the technical objectives and clearly demonstrates the technical feasibility of the innovative CUTS. The novel CUTS:
- Reduces the environmental impact of the machining process by 21 percent
for dry machining and by a factor of two for jet cooling with a synthetic
coolant.
- Increases the tool life by 50 percent at high cutting speeds and by 700
percent at low cutting speeds at working fluid volume flow rates 250 times
less than a typical synthetic coolant.
- Decreases part production costs by at least 20 percent compared to dry cutting
and jet cooling with a synthetic coolant.
- Improves the final part quality while maintaining a high degree of dimensional accuracy compared to dry cutting and jet cooling with a synthetic coolant.
The Creare CUTS is a unique opportunity to increase the environmental friendliness of the machining process while significantly decreasing the production cost. Creare Incorporated believes that there are at least four significant markets for CUTS technology insertion:
- Environmentally Friendly Machining Systems. The results of this project
demonstrated that such a system is technically feasible and commercially viable.
- Vision-Based Control of Machining Processes. The elimination of flood
or jet coolants opens the door for vision-based control for large-scale manufacturing
processes or the processing of hazardous materials.
- High-Performance Machine Tool Systems for Advanced Materials Processing.
Combining this technology with advanced cutting tools will increase their
ability to withstand the high cutting forces associated with difficult-to-machine
materials, such as ceramics, titanium, superalloys, ceramic-matrix composites,
and metal-matrix composites (MMCs). Use of this technology will enable faster,
more accurate processing of these materials for a wide variety of engineering
applications.
- Ultra-High Accuracy Machining Using Precise Cutting Tool Temperature Control. A CUTS coupled to an appropriate control strategy would enable precise thermal control for high-accuracy machining.
Creare Incorporated has taken some actions during the Phase I research project to accelerate the commercialization of this technology. With the help of commercialization assistance from the U.S. Environmental Protection Agency, potential partners were identified to carry the technology to commercialization. Potential partners include a large manufacturer of cryogens and cryogenic systems, a producer of metal-cutting systems for high-volume applications, and a manufacturer of finished MMC parts.
Conclusions:
This Phase I research project has clearly demonstrated that the proof-of-concept for the CUTS meets or exceeds all technical and economic objectives. The innovative CUTS is technically feasible and commercially viable. When compared to dry cutting and jet cooling with a synthetic coolant, it was demonstrated that the novel CUTS significantly reduces the environmental impact of the machining process, increases the tool life, decreases part production cost, and improves the final part quality. The Creare CUTS is a unique opportunity to increase the environmental friendliness of machining processes while significantly decreasing the production cost. These findings and initial commercialization efforts clearly justify the continuation of this project to the next phase, which will focus on design optimization, integration, and testing.
Supplemental Keywords:
machining, cutting fluids, fluidless machining, environmentally conscious machining, toxic emissions, dry cutting, jet cooling, ceramics, titanium, superalloys, ceramic-matrix composites, metal-matrix composites, SBIR, RFA, Scientific Discipline, Sustainable Industry/Business, cleaner production/pollution prevention, Physics, Environmental Chemistry, Sustainable Environment, Technology for Sustainable Environment, Economics and Business, Environmental Engineering, in-process changes, dry machining, cleaner production, waste minimization, waste reduction, environmentally conscious manufacturing, nanocoatings, clean technology, cutting tools, alternative materials, cutting fluids, coating processes, process modification, machining, innovative technology, pollution prevention, nonocaotings, industrial innovations, source reductionSBIR Phase II:
Low-Cost Machining Without Cutting Fluids | Final ReportThe perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.