Dry Machining

Cost and performance of dry machining operations were documented using a pollution prevention template. This information will be useful to companies considering converting to dry machining from the use of cutting fluids.

A major function of cutting fluids is the removal of chips from the machining area, as well as transport of thermal energy. However, cutting fluids also present problems for employee health, disposal costs, and machinery maintenance.

Dry machining circumvents the need for cutting fluids. It has reached the stage where it is proven to work under defined conditions (high speeds and feeds, chip movement exists, correct tools in use). Most auto manufacturers are now employing dry machining. High capital costs will be a barrier to adoption of dry machining by the small job shop.

Contact:           John Bulloch, MTU, 906/487-3418

                        jbulloc@mtu.edu

Research Needs in Dry Machining

Introduction:

Issues such as the role of cutting fluids in machining and the impact of process wastes on the environment have long been under-emphasized as they seldom affect product value directly. However, an increasing awareness exists that the environmental and economic impacts of cutting fluid may surpass the benefits.

The use of cutting fluids presents a number of problems. Employee health and safety is threatened by cutting fluid inhalation, skin absorption, and ingestion. The most prevalent health problems of machine shop employees are dermatitis and respiratory problems. Due to potential health hazards and environmental impacts, the costs of using and disposing of cutting fluids have significantly increased. Additionally, the cleaning of machinery due to cutting fluid deposits is dirty, time-consuming, and disruptive to production.

Benefits of Dry Machining:

Dry machining, on the other hand, would circumvent the need for cutting fluid purchase and disposal, eliminate production shutdown for machinery clean-up, and improve employee health and safety. Dry machining would also result in more environmentally-friendly clean-up of workpieces, as no oil would have adhered to the workpiece. Moreover, chips will be uncontaminated, allowing for greater recycling. The cost advantages of dry machining include: no coolant, coolant pumps, chillers, or filters to purchase or maintain; clean chips to sell; and reduced workplace liability.

Technology Summary:

Dry machining technology and research has reached the stage where it is known that it does indeed work and under what conditions it can work. For instance, for dry machining to be properly employed, the correct tools need to be in use (specifically, PCD and CVD tools), speeds and feeds need to be high enough, and conditions need to be amenable to chip movement. Most auto manufacturers are employing some form of dry machining, particularly General Motors and Ford. As of January 1995, eight dry diamond high-speed machining systems had been installed or purchased by the Big 3 automakers. Additionally, facilities exist that rely solely on dry machining.

Research Needs:

Some limitations, or needs for further research, do exist, limiting the broad applicability of dry machining. Specifically, further research needs to be conducted on chip removal, designing better tools, and dry machining steel.

A major function of cutting fluids is the removal of chips from the machining area. Suction equipment has been employed to fulfill this function, but is expensive. Suction is also not always effective, depending on surface geometry. Material can remain on the cutting tool edge, causing built-up edge phenomena.

The problem with steel is due to the high heat need for machining steel. Another major function of cutting fluids, transport of thermal energy, needs to be fulfilled in steel, as the residual heat in machining steel is very high.

Tool modification is another need for further research, as dry machining, effective only at high speeds, results in higher temperatures and therefore, increased tool wear. Research has been conducted in the modification of tool geometry and tool coatings. Dry machining tools need to be designed to guarantee toughness and hardness, particularly high hot hardness. New coatings, particularly diamond coatings, act as a separator of the tool and workpiece and function as a coolant.

Potential Partners for Research:

Potential partners for further research in dry machining have been identified. Specifically, these include:

• Ford Motor Company
• Daimler-Benz
• MT-AMRI (a coordinated effort of the following universities)
• Michigan Technological University
• University of Nebraska
• University of California - Berkley
• University of Illinois - Urbana - Champaign

• LeBlond Makino
• Turchan, Inc.
• Guhring

Summary:

In summary, the following research needs have been identified for dry machining to be more broadly applicable:

• Chip removal
• fulfill the coolant function of chip removal in dry machining
• reduce build-up edge phenomena

• Tool modification
• increase tool life in conjunction with dry machining
• increase high hot hardness

• Dry machining steel
• fulfill the coolant function of transporting thermal energy from the workpiece

• Economic feasibility and application of dry machining in smaller shops

Waterborne Wood Finishing

Waterborne wood finishes are having some application success in the wood finishing industry primarily for cabinet makers, and low-to-medium-end furniture manufacturers. High-end furniture manufacturers have not been able to achieve comparable quality with waterborne finishes compared to solvent borne finishes. Even cabinet and medium-end furniture manufacturers have to be cautious of quality due to grain-raising and different sheens. Extended drying times also present production and throughput concerns for some manufacturers.

Effectively, waterborne coating technologies are proven, but due to barriers that create uncertainty in the industry, it is the objective of the R&TT workgroup to develop and support information tools, and share this information with Roundtable membership.

Contact:           Cindy McComas, MnTAP, 612/627-4556

                        mccom003@tc.umn.edu

SCOPING STUDY

Waterborne Wood Finishing

1.1       Statement of Problem

The wood finishing national emission standards for hazardous air pollutants NESHAP requires wood furniture and kitchen cabinet manufacturers and other wood working businesses to use coatings with an average Hazardous Air Pollutant (HAP) content less than or equal to 1.0 lb HAP per lb. of solid applied. This requirement must be met by November 1997 for large manufacturers and by November 1998 for small less than 100 employee businesses. Many of these affected plants are located within current or potential ozone non-attainment areas which limit their ability to switch to non-HAP solvents because of restriction on Volatile Organic Compound (VOC) emissions that apply to non-attainment areas. In addition to the NESHAP, the new Ozone standard may put even more pressure on wood finishers in these areas.

Even before the NESHAP became law, waterborne wood furniture coatings were being touted as a primary means of complying with the upcoming NESHAP. However, many facilities that had tried water-borne coatings were experiencing technical difficulties with these coatings. Examples of technical difficulties include: raising of the wood grain due to exposure to water, slowing of production due to increased drying time, and difficulty repairing or touching-up the coatings when necessary.

On the other hand, some companies have reported successful implementation of waterborne finishing materials into their production lines, often with an improvement in product quality. A common requirement that these successful companies expressed was a need to work with different suppliers to identify a finishing material that was suitable to the individual plant's need. They stated that the range of applicability of individual waterborne coating formulations is much more narrow than for nitrocellulose lacquers. Unfortunately, the companies that have given up on waterborne finishing technologies have done so after attempting to use material provided by one or two suppliers who could not meet their process needs.

Another difficulty the industry has struggled with is customer acceptance of a different finished look that these coatings produce on the final coated product. It could be that marketing professionals would benefit from some form of additional training to convince customers that the appearance of the finished product is a better look than the previous coatings.

1.2       Project Goals

1.2.1    Project Area (1): Demonstration of New Waterborne Technologies

To advance the use of waterborne coating technology in the wood finishing industry, unbiased information from a demonstration project is needed regarding performance characteristics of various resin types and formulations relative to grain-raising, drying time, finish sheen, and repairability. This type of unbiased information will potentially enable wood finishers to make more informed decisions concerning formulations to evaluate in their particular coating process. Also needed are the identification and demonstration of advanced techniques to minimize grain-raising to permit increased utilization of waterborne finishing materials for the early components (stains and wash-coats) of a finishing sequence.

1.2.2    Project Area (2): Collaborative Efforts to Train Industry Sales Professionals

This project would encompass the collaborative efforts of industry experts, NPPR, and any contractor(s) involved to provide additional training and education of marketing and sales professionals to address their bias against waterborne finishes arising from past grievances of appearance problems associated with waterborne coating technology.

1.3       Pollution Prevention Benefits:

This technology has the potential to reduce VOC and HAP emissions in this industry by 50-75%. Also potential to transfer the technology to other sectors.

1.4       Tasks to Be Accomplished

1.4.1    Project Area (1):

Literature search and input from industry experts. A literature search could be conducted to identify the information that is currently available on new waterborne wood coating technologies. In addition, discussions with industry experts would help identify the most practical and beneficial demonstration to conduct that would have the greatest probability of success in the industry.

Demonstration. Conduct a demonstration at a representative wood finishing facility that is willing to cooperate and is willing to share the information with others in their industry.

Documentation. Document the literature search and demonstration project and communicate this information to small businesses via Trade Associations and electronic media such as CAGE and Enviro$ense.

1.4.2    Project Area (2):

Training Video. A training video could be developed on how to use new technology and the benefits of the finished coated product while showing how to re-educate the customer on the issue of appearance.

Training Seminar. Develop a streamlined, half- or one-day training seminar for wood finishers on technology benefits and ways to present the new coated products to the customer

Update Electronic Information Media. Update both the CAGE program and the Enviro$ense database with training seminar information.

1.5       Significance of Sector Nationally:

            There are over 9000 wood furniture and kitchen cabinet manufacturers in the United States.

1.6       Current Source of Information

• EPA Office of Air Quality Planning and Standards
• Midwest Research Institute (EPA contractor for the Wood Furniture NESHAP)
• American Furniture Manufacturer's Association
• Coatings Suppliers (e.g., Lilly, Akzo-Nobel, PPG, Valspar, Sherwin-Williams)
• EPA Office of Research and Development
• State Pollution Prevention Programs
• National Paint and Coatings Association

1.7       Expertise Needed to Carry Out Project

• Knowledge and rapport with wood furniture manufacturing industry
• Knowledge of coatings techniques and technologies

1.8       Utility to Other Sectors

Advancement of waterborne coatings technologies and acceptance of waterborne finishes for this "fashion" industry could overcome hurdles to implementation of the technology in several other sectors.

1.9       Time Line

The wood finishing NESHAP requires wood furniture and kitchen cabinet manufacturers and other wood working businesses to use coatings with an average Hazardous Air Pollutant (HAP) content less than or equal to 1.0 lb. HAP per lb. of solid applied by November 1997 for large manufacturers and by November 1998 for small less than 100 employees businesses.

1.10     Level of Effort/Budget

1.10.1  Project Area (1):

1.10.2  Project Area (2):

1.11     Deliverables

* - Time from date of initiation of funding

1.12     Lead Agency/Organization

NC Division of Pollution Prevention and Environmental Assistance.

1.13     Partners

Research Triangle Institute

American Furniture Manufacturers Association

Kitchen Cabinet Manufacturers Association

Architectural Woodworking Institute

1.14     Funding Sources

U.S. Environmental Protection Agency

Electric Power Research Institute

Closed Loop Aqueous Cleaning

A pollution prevention template approach was used to document the cost and performance of 6 closed loop aqueous cleaning systems. The template will be used by technical assistance staff to help businesses close loop their systems.

Efforts to replace ozone-depleting cleaning solvents have been occurring since the late 1980s as a result of the Montreal Protocol, which dictated a world-wide phase out of the manufacture of many ozone-depleting chemicals. Of the cleaning alternatives that have been implemented by manufacturers, one of the most popular is aqueous cleaning systems. Closed-looping these systems further reduces wastewater discharge.

Results from this effort indicate that closed loop systems in a variety of configurations can be used to reuse aqueous cleaning solution without detrimental problems due to contaminant build-up.

Contact:           Karen Thomas, TURI, 978/934-3143

                        karen_thomas@uml.edu

Document the Performance of Closed-Loop Aqueous Cleaning Technologies

BACKGROUND: Efforts to replace ozone-depleting solvents such as Freon, often used in vapor degreasing systems, primarily have occurred since the late 1980s as a result of the Montreal Protocol, which dictated a worldwide phase-out of many ozone-depleting chemicals. In the past decade, there has also been significant efforts to replace cleaning solvents that, regardless of their ozone-depleting potential, are known or suspected carcinogens.

Of the cleaning alternatives that have been implemented by manufacturers, one of the most popular is aqueous cleaning systems. These systems have been popular because the cleaning solution is not regulated and does not have the potential to become regulated, and because with the proper system design, aqueous cleaners have been proven very effective in many industrial cleaning applications that previously used regulated solvents.

A primary disadvantage of aqueous processes is that they generate wastewater streams. which must be properly disposed of and may require treatment prior to discharge. Whether this spent aqueous cleaner is a problem will be case-specific and will depend on the volume of spent cleaner generated, the nature of the contaminants, and the local water discharge regulations. For larger volume throughputs, fees for fresh water and sewer discharge can also become a factor.

One way to avoid this problem is to close loop the aqueous cleaning system. This requires removal of undesirable contaminants that interfere with cleaning efficiency, typically by using some type of filtration. However, when removing contaminants the closed-loop system has to leave any special cleaning additives in solution, such as surfactants, or they need to be added back in through a make-up system.

Simple processing of aqueous cleaning solutions using gross separation techniques for treatment prior to discharge such as oil/water separators or simple filters is widely used and well known, but more sophisticated approaches that can allow full closed-looping, such as membrane filtration, are still not fully understood by many manufacturers. To date, the majority of work done to extend cleaner life has been done within private companies, and is not publicly available.

Additional applied research and documentation of industry experiences is necessary to provide an available knowledge base to help manufacturers reduce the waste water streams they generate as a result of aqueous cleaning. Extending the life of the cleaning solution will reduce both cleaner purchases and wastewater treatment costs. Access to this type of information would allow manufacturers to design better closed-loop systems for their aqueous cleaners at a lower cost. It would also encourage more manufacturers to work towards closed-looping their current systems. This would have the end result of reducing water use and water pollution generated by aqueous cleaning processes. It could also reduce the water discharge permitting requirement for those facilities using aqueous cleaning systems.

OBJECTIVES:

1. Document the actual performance of different filtration techniques and equipment types used to recycle the aqueous cleaners, in terms of removing various typically encountered contaminants, such as oil and grease.

1. Document the effect of different filtration techniques and recycling equipment on the aqueous cleaning solution effectiveness (i.e., does it remove cleaning additives when it removes contaminants).

1. Conduct cost analyses of installed closed-loop systems at manufacturing facilities.

GENERAL APPROACH: The Pollution Prevention Technology Application Analysis Template (P2 template), developed by a consultant with EPA Region I support (originally for remediation technologies), will be used to document cost and performance of existing closed loop aqueous cleaning systems in operation. In some cases existing case studies will be used to feed data and information into the P2 template format. In other cases, data will be collected from companies to complete the P2 template format.

At this point, a number of states (MA, IL, NC, and MN) have joined together through a workgroup of the NPPR to put existing case studies into the P2 template format. The P2 template has been modified to incorporate parameters that are specific to data collection for closed loop aqueous cleaning for technology performance, baseline parameters, cost information, and regulatory information. Each state is committed to documenting 1-3 case studies, but staff resources continue to be limiting.

Beyond the current efforts of the states, resources are needed to collect data from 25 shops with closed loop systems where case studies do not exist and then put into P2 template format. The NPPR workgroup plans to gather data from a range of separation methods, including simple (bag) filtration, membrane filtration, gravity plate separation, evaporation/condensation systems, and hybrid systems.

NPPR believes using the P2 application template provides a number of benefits: 1) the template provides standardization of technology reviews and sets minimum information requirements (cost and performance) and state technical assistance (TA) providers will accept more widely demonstrated technology; 2) the template provides a consistent reporting format that will promote technology transfer and reduce the time it takes TA providers to find relevant and useful information; 3) the template provides enough flexibility so that the reviews can be tailored to meet single technology applications, or expanded to collect cost and performance data on a range of applications.

APPROXIMATE SCHEDULE: Technology verification for cost and performance -- 18 months. Total time -- 18 months.

Closed Mold Fiberglass Reinforced Plastic

Traditional open mold and spray resin applications to produce a variety of fiberglass reinforced plastic products result in significant stryrene emissions. Styrene emissions may be reduced by minimizing resin contact with air, such as through the use of a closed mold system. There is incentive to reduce styrene due to lower OSHA standards and CAAA MACT standards. At the outset, equipment cost may appear to be a barrier to implementing closed mold, but many companies using closed mold are experiencing competitive advantages and have not been willing to share information.

Closed mold case studies are needed to document cost and performance using the pollution prevention template format.

Contact:           Cindy McComas, MnTAP, 612/627-4556

                        mccom003@tc.umn.edu

Demonstrate and Document the Performance of Closed Molding Technologies to Reduce Styrene Emissions From Fiberglass Reinforced Plastics Operations

BACKGROUND: Reinforced plastics make up about 5% of the total plastic demand, but new developments in blending, compounding, and fabrication will rapidly increase this demand with new product developments in many areas. Thousands of products are manufactured from reinforced plastics. Examples include hulls for boats and canoes; bodies for recreational vehicles such as snowmobiles; building panels, utility poles; sporting equipment, appliances, and power tools; bathtub, shower, and vanity installations; automotive, aerospace, and aircraft components; and structural components for chemical process equipment and storage tanks. Eighty percent of the companies are small and have less than 20 employees.

A variety of processing techniques are used to produce these products, including open molding hand or spray layup, closed molding, filament winding, continuous lamination, pultrusion, and casting. Approximately 80% of the industry uses the open or closed molding processing technique. Although the processes are different, the types of wastes generated as similar, including styrene emissions, cured resin scrap, and solvent from clean-up. A commonly used resin is unsaturated polyester resin (depending on the application) which is supplied in liquid form typically dissolved in styrene monomer (reactive diluent) as the solvent. Styrene emissions are the primary environmental and health issue.

Concern about the health effects of workplace exposure to styrene vapors, as well as the contribution of VOCs such as styrene to air pollution are prompting the fiberglass industry to implement practices that reduce the level of styrene emitted by polyester resins. The OSHA workplace airborne threshold limit value (TLV) is 100 parts per million, although in some states it is 50 ppm. Recently, five industry trade groups who use styrene-containing resins entered into an agreement with OSHA to reduce 8-hour exposures at member facilities to below 50 ppm by June 1997.

In addition, two new CAAA National Emission Standards for Hazardous Air Pollutants (NESHAP) will require future reductions of styrene emissions. Maximum Achievable Control Technology (MACT) standards are schedule to be promulgated for the reinforced plastic composites source category by mid-1988, and for the boat manufacturing source category by the year 2000. Conventional control technology options for these operations can be expensive due to the relatively high volumes of air and low styrene concentrations at typical facilities.

Two source categories build fiber reinforced plastic (FRP) products. The reinforced plastic composites source category has over 680 facilities, with total styrene emissions currently about 17,000 tons per year. Facilities conducting gel coating and open molding processes account for 84 percent of the total styrene emissions. The boat manufacturing source category has been estimated to have at least 145 major facilities with total hazardous air pollutant (HAP) emissions of 7,000 tons per year. Hazardous air pollutants emitted in boat manufacturing include styrene and methyl methacrylate, present in most gel coat materials. Therefore, combined HAP emissions, primarily styrene, from the two source categories are over 24,000 tons per year (TRI 1993).

The most effective styrene reduction strategies rely upon minimizing resin contact with air (reducing atomization), keeping as much styrene monomer from leaving the resin system, and maximizing it into the product (improving transfer efficiency). Some styrene reductions can be achieved through resin application techniques, operator training, and the use of low-styrene resins. However, the most effective technology that significantly reduces styrene emissions is the use of closed molding systems. Emissions from closed molding operations are lower due to the enclosed nature of the molding operations which minimizes contact with air. Emissions are further reduced by confining the resins in the mold until curing is complete. The benefits of closed molding include improved product quality, reduced styrene emissions, better improved physical characteristics, reduced energy usage over open mold and optimized glass-to-resin rations. In addition, trim and scrap waste is also reduced in closed molding processes, because catalyzed resins are pumped, not sprayed, although other waste types may be generated.

Use of closed molding processes has not been widely used due to the high cost of the equipment, the necessary mold conversions, and slower cycle times (for some technology applications) and cosmetic appearances (for certain process methods). Accomplishment of the following will help advance the adoption of closed molding technologies to reduce styrene emissions.

OBJECTIVES:

1. Develop a matrix of appropriate closed molding options/processes and resin application options (spray lay-up, flow coating, pressure-red rolling, HVLP, etc.) that meet the needs of specific product applications (boat manufacturing, tub/shower manufacturing, etc.).

1. Conduct technology verification using the Pollution Prevention Technology Application Analysis Template (P2 template) to document cost and performance of existing closed molding systems currently in use for various product manufacture applications.

1. Conduct a test project in a controlled chamber to gather data on reduced styrene from various closed molding technologies to include in the MACT.

GENERAL APPROACH: Development and use of a matrix that indicates the best resin applications and molding technologies to reduce styrene emissions for manufacturing a specific product can be used as an education and practical application tool for selecting systems.

Documentation of the cost and performance of existing closed molding systems (especially compared to open molding) in a number of shops for various product types using the P2 template tool would be very useful to persuade other FRP shops that closed molding holds potential to reduce costs and improve quality, as well as reduced styrene emissions. NPPR believes that using the P2 application template assures some level of technology verification, reporting consistency, and flexibility of different technologies.

Conducting a test project in a controlled chamber comparing styrene emissions from closed molding versus open molding will provide data that will be useful to EPA as the MACT standards are developed. The MACT standard could be used as a regulatory tool to push the adoption of closed molding technologies.

APPROXIMATE SCHEDULE: Technology verification for cost and performance -- 12 months. Test project -- 12 months. Total time -- two years.

Waterborne Adhesives

Waterborne adhesives are being readily adopted for use in broad industrial applications, especially for large end users. Capital costs are low for machinery and technology to manufacture and use low VOC adhesives, even for small companies. Two primary incentives to move from solvent based adhesives to water based adhesives have been:

• OSHA standard reduction for methylene chloride (common adhesive carrier) from 500 ppm to 25 ppm.
• National emission standards for HAPs in several coating categories.
• VOC emission standards for end-users to use adhesives with a limited VOC content.

The R&TT workgroup objective is to advance the knowledge of performance-proven, low emitting industrial adhesive technologies through the support and development of information tools.

Contact: Dean Cornstubble, RTI, 919/541-6813

dean@rti.ord

Adhesive Bonding: A Review of Current Technologies for Reducing Solvent Emissions