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Comminution by the Attrition Grinding Process

Description: From Introduction: "Studies also were made to determine the efficiency of the process in grinding a variety of individual minerals, pigments, metals, and ceramics. As a result of this work, the process was adapted by industry to produce paper-filler-grade kaolin and ultrafine titania pigment on a commercial scale. This report summarizes the results of the Bureau's research studies and includes a brief description of the commercial applications."
Date: unknown
Creator: Stanczyk, Martin H. & Feld, I. L.
Partner: UNT Libraries Government Documents Department

In-process EDM truing to generate complex contours on metal-bond, superabrasive grinding wheels for precision grinding structural ceramics

Description: The demand and use of precision grinding of structural ceramics continue to increase as the worldwide advanced ceramic industry surpasses $20 billion is sales. Included in this industry are engineering structural ceramics, electronic ceramics, bioceramics and others. These materials are used in applications such as engine components, casting and extrusion dies, bearings, medical implants, nozzles, thermal insulators, and more. Along with the variety of ceramic applications comes a broad range of precision requirements, which in turn leads to various required processes to accommodate a spectrum of specifications. A process for grinding ceramic components to micrometer tolerances was employed and further developed at Lawrence Livermore National Laboratory for two separate grinding projects.
Date: August 1, 1997
Creator: Piscotty, M.A.; Davis, P.J.; Saito, T.T.; Blaedel, K.L. & Griffith, L.
Partner: UNT Libraries Government Documents Department

A Mill for the Quantitative Grinding of TF₄

Description: Abstract: "A monel metal rod mill has been designed, built, and tested for grinding five hundred gram batches of anhydrous tuballoy tetrafluoride to a fineness such that one hundred per cent will pass an eighty mesh screen; the grinding being accomplished without loss of material, and with the addition of less than two hundred parts per million of contaminating metals. The grinding time per batch is not more than fifty minutes."
Date: 1945
Creator: Webb, A. D.; Peed, W. F.; Pancoast, L. H. & Johnsson, Karl Otto
Partner: UNT Libraries Government Documents Department

Precision grinding process development for brittle materials

Description: High performance, brittle materials are the materials of choice for many of today's engineering applications. This paper describes three separate precision grinding processes developed at Lawrence Liver-more National Laboratory to machine precision ceramic components. Included in the discussion of the precision processes is a variety of grinding wheel dressing, truing and profiling techniques.
Date: April 1, 1999
Creator: Blaedel, K L; Davis, P J & Piscotty, M A
Partner: UNT Libraries Government Documents Department

Grinding miniature pinion gears

Description: Although grinding inherently produces a better involute form and finer surface finish than other basic gear-fabrication methods, equipment, and experience in grinding 120-pitch gears with 0.100inch pitch diameter were not available when Bendix Kansas City placed a process development contract with the Fellows Company. Bendix had been producing a functional miniature gear by hobbing, but the required surface finish was borderline and burrs on the part were difficult to remove. As a result of this project, a repeatable process was developed for grinding the tooth form and maintaining a l6AA surface finish with minimum burrs. An experimental machine was used in this process development; production equipment is not yet available in U. S. industry for this process but could be developed. (auth)
Date: October 1, 1973
Creator: Stiles, R.W.
Partner: UNT Libraries Government Documents Department

Grinding machines

Description: This report provides the definition of grinding and discusses different processes, types, and operations of grinding.
Date: November 26, 1940
Creator: United States. Army. Air Corps.
Partner: UNT Libraries Government Documents Department

Next generation grinding spindle for cost-effective manufacture of advanced ceramic components

Description: Finish grinding of advanced structural ceramics has generally been considered an extremely slow and costly process. Recently, however, results from the High-Speed, Low-Damage (HSLD) program have clearly demonstrated that numerous finish-process performance benefits can be realized by grinding silicon nitride at high wheel speeds. A new, single-step, roughing-process capable of producing high-quality silicon nitride parts at high material removal rates while dramatically reducing finishing costs has been developed.
Date: January 1, 2000
Creator: Kovach, J.A. & Laurich, M.A.
Partner: UNT Libraries Government Documents Department

Electrolytic In-process Dressing (ELID) for high-efficiency, precision grinding of ceramic parts: An experiment study

Description: This report describes Electrolytic In-process Dressing (ELID) as applied to the efficient, high-precision grinding of structural ceramics, and describes work performed jointly by Dr. B.P. Bandyopadhyay, University of North Dakota, and Dr. R. Ohmori, of the Institute of Physical and Chemical Research (RINEN), Tokyo, Japan, from June through August, 1994. Dr. Ohmori pioneered the novel ELID grinding technology which incorporates electrolytically enhanced, in-process dressing of metal bonded superabrasive wheels. The principle of ELID grinding technology is discussed in the report as will its application for rough grinding and precision grinding. Two types of silicon nitride based ceramics (Kyocerals Si{sub 3}N{sub 4}, and Eaton`s SRBSN) were ground under various conditions with ELID methods. Mirror surface finishes were obtained with {number_sign} 4000 mesh size wheel (average grain size = 4 {mu}m). Results of these investigations are presented in this report. These include the effects of wheel bond type, type of power supply, abrasive grit friability, and cooling fluid composition. The effects of various parameters are discussed in terms of the mechanisms of ELID grinding, and in particular, the manner of boundary layer formation on the wheels and abrasive grit protrusion.
Date: August 1, 1995
Creator: Bandyopadhyay, B.P.
Partner: UNT Libraries Government Documents Department

Ball-Mill Grinding

Description: Report issued by the Bureau of Mines discussing the ball-mill grinding technique. Different methods of mill grinding are presented and compared with ball-mill grinding. This report includes tables, illustrations, and photographs.
Date: 1937
Creator: Coghill, Will H. & DeVaney, Fred D.
Partner: UNT Libraries Government Documents Department

Surface waviness resulting from single point diamond dressing in cylindrical grinding

Description: This paper describes an experimental investigation of workpiece surface waviness that stems from poor single point diamond wheel dressing procedures in cylindrical grinding. If done improperly, single point dressing can produce a thread on the grinding wheel surface that is then imposed on the workpiece during machining. The circumferential waviness exhibited by the threaded workpiece is similar to that resulting from one per rev vibrations of the grinding wheel. In order to differentiate between these two sources of waviness, a geometrical approach to predicting the circumferential and axial waves produced during grinding is presented. The concepts presented are illustrated through a series of plunge grinding tests incorporating dressing procedures of varying quality. Test results verify that dressing induced circumferential waviness is similar to waviness resulting from one per rev type vibrations of the grinding wheel. The two sources can be distinguished, however, through examination of the workpiece waviness in the axial direction.
Date: May 1, 1996
Creator: Redmond, J.; Hinnerichs, T. & Apodaca, E.
Partner: UNT Libraries Government Documents Department

Ceramic component manufacturing process development. Final report

Description: Ceramic materials are well suited for applications where temperature, wear, and corrosion resistance are necessary. The toughness and wear resistance properties that make ceramics desirable, also make fabrication of parts difficult. The objective of this CRADA was to increase the grinding efficiency on Ceradyne Incorporated silicon nitride. This was to be accomplished through optimization of grinding wheel life and increasing silicon nitride material removal rates. Experiments were conducted to determine the relationship between grinding parameters, wheel wear, and material removal rates. Due to excessive, unexplained variation in the experimental results, a consistent relationship between the selected grinding parameters and wheel wear could not be established. Maximum material removal rates were limited by spindle and table drive power. Additional experiments were conducted to evaluate high speed grinding. When compared to conventional grinding speeds, the material removal rates using high speed grinding (13,000 SFM) increased by a factor of five to ten with no degradation of fracture strength.
Date: September 30, 1996
Creator: Robinson, S.
Partner: UNT Libraries Government Documents Department

Working with the superabrasives industry to optimize tooling for grinding brittle materials

Description: The optics manufacturing industry is undertaking a significant modernization, as computer-numeric-controlled (CNC) equipment is joining or replacing open-loop equipment and hand lapping/polishing on the shop floor. Several prototype CNC lens grinding platforms employing ring tools are undergoing development and demonstration at the Center for Optics Manufacturing in Rochester, NY, and several machine tool companies have CNC product lines aimed at the optics industry. Benefits to using CNC ring tool grinding equipment include: essentially unlimited flexibility in selecting radii of curvature without special radiused tooling, the potential for CIM linkages to CAD workstations, and the cultural shift from craftsmen with undocumented procedures to CNC machine operators employing computerized routines for process control. In recent years, these developments, have inspired a number of US optics companies to invest in CNC equipment and participate in process development activities involving bound diamond tooling. This modernization process,extends beyond large optics companies that have historically embraced advanced equipment, to also include smaller optical shops where a shift to CNC equipment requires a significant company commitment. This paper addresses our efforts to optimize fine grinding wheels to support the new generation of CNC equipment. We begin with a discussion of how fine grinding fits into the optical production process, and then describe an initiative for improving the linkage between optics industry and the grinding wheel industry. For the purposes of this paper, we define fine wheels to have diamond sizes below 20 micrometers, which includes wheels used for what is sometimes called medium grinding (e.g. 10-20 micrometers diamond) and for fine grinding (e.g. 2-4 micrometers diamond).
Date: May 1, 1996
Creator: Taylor, J.S.; Piscotty, M.A.; Blaedel, K.L. & Gray, F.A.
Partner: UNT Libraries Government Documents Department

Comparison of Materials for Use in the Precision Grinding of Optical Components

Description: Precision grinding of optical components is becoming an accepted practice for rapidly and deterministically fabrication optical surfaces to final or near-final surface finish and figure. In this paper, a comparison of grinding techniques and materials is performed. Flat and spherical surfaces were ground in three different substrate materials: BK7 glass, chemical vapor deposited (CVD) silicon carbide ceramic, and sapphire. Spherical surfaces were used to determine the contouring capacity of the process, and flat surfaces were used for surface finish measurements. The recently developed Precitech Optimum 2800 diamond turning and grinding platform was used to grind surfaces in 40mm diameter substrates sapphire and silicon carbide substrates and 200 mm BK7 glass substrates using diamond grinding wheels. The results of this study compare the surface finish and figure for the three materials.
Date: December 31, 1997
Creator: Evans, Boyd M. III; Miller, Arthur C. Jr. & Egert, Charles M.
Partner: UNT Libraries Government Documents Department

Effects of imbalance and geometric error on precision grinding machines

Description: To study balancing in grinding, a simple mechanical system was examined. It was essential to study such a well-defined system, as opposed to a large, complex system such as a machining center. The use of a compact, well-defined system enabled easy quantification of the imbalance force input, its phase angle to any geometric decentering, and good understanding of the machine mode shapes. It is important to understand a simple system such as the one I examined given that imbalance is so intimately coupled to machine dynamics. It is possible to extend the results presented here to industrial machines, although that is not part of this work. In addition to the empirical testing, a simple mechanical system to look at how mode shapes, balance, and geometric error interplay to yield spindle error motion was modelled. The results of this model will be presented along with the results from a more global grinding model. The global model, presented at ASPE in November 1996, allows one to examine the effects of changing global machine parameters like stiffness and damping. This geometrically abstract, one-dimensional model will be presented to demonstrate the usefulness of an abstract approach for first-order understanding but it will not be the main focus of this thesis. 19 refs., 36 figs., 10 tables.
Date: June 1, 1997
Creator: Bibler, J.E.
Partner: UNT Libraries Government Documents Department

Innovative technology summary report: Concrete grinder

Description: The Flex concrete grinder is a lightweight, hand-held concrete and coating removal system used for decontaminating or stripping concrete surfaces. The US Department of Energy has successfully demonstrated it for decontaminating walls and floors for free release surveys prior to demolition work. The grinder is an electric-powered tool with a vacuum port for dust extraction and a diamond grinding wheel. The grinder is suitable for flat or slightly curved surfaces and results in a smooth surface, which makes release surveys more reliable. The grinder is lightweight and produces very little vibration, thus reducing worker fatigue. The grinder is more efficient than traditional baseline, tools at removing contamination from concrete surfaces (more than four times faster than hand-held pneumatic scabbling and scaling tools). Grinder consumables (i.e., replacement diamond grinding wheel) are more expensive than the replacement carbide parts for the scaler and scabbler. However, operating costs are outweighed by the lower purchase price of the grinder (50% of the price of the baseline scaler and 8% of the price of the baseline scabbler). Overall, the concrete grinder is an attractive alternative to traditional scabbling and scaling pneumatic tools. To this end, in July 1998, the outer rod room exposed walls of the Safe Storage Enclosure (SSE), an area measuring approximately 150 m{sup 2}, may be decontaminated with the hand-held grinder. This concrete grinder technology was demonstrated for the first time at the DOE`s Hanford Site. Decontamination of a sample room walls was performed at the C Reactor to free release the walls prior to demolition. The demonstration was conducted by onsite D and D workers, who were instructed by the vendor prior to and during the demonstration.
Date: September 1, 1998
Partner: UNT Libraries Government Documents Department

Innovative grinding wheel design for cost-effective machining of advanced ceramics

Description: This Final Report covers the Phase II Innovative Grinding Wheel (IGW) program in which Norton Company successfully developed a novel grinding wheel for cost-effective cylindrical grinding of advanced ceramics. In 1995, Norton Company successfully completed the 16-month Phase I technical effort to define requirements, design, develop, and evaluate a next-generation grinding wheel for cost-effective cylindrical grinding of advanced ceramics using small prototype wheels. The Phase II program was initiated to scale-up the new superabrasive wheel specification to larger diameters, 305-mm to 406-mm, required for most production grinding of cylindrical ceramic parts, and to perform in-house and independent validation grinding tests.
Date: May 1, 2000
Creator: Licht, R.H.; Kuo, P.; Liu, S.; Murphy, D.; Picone, J.W. & Ramanath, S.
Partner: UNT Libraries Government Documents Department

Vitreous bond CBN high speed and high material removal rate grinding of ceramics

Description: High speed (up to 127 m/s) and high material removal rate (up to 10 mm{sup 3}/s/mm) grinding experiments using a vitreous bond CBN wheel were conducted to investigate the effects of material removal rate, wheel speed, dwell time and truing speed ratio on cylindrical grinding of silicon nitride and zirconia. Experimental results show that the high grinding wheel surface speed can reduce the effective chip thickness, lower grinding forces, enable high material removal rate grinding and achieve a higher G-ratio. The radial feed rate was increased to as high as 0.34 {micro}m/s for zirconia and 0.25 {micro}m/s for silicon nitride grinding to explore the advantage of using high wheel speed for cost-effective high material removal rate grinding of ceramics.
Date: August 1, 1998
Creator: Shih, A.J.; Grant, M.B.; Yonushonis, T.M.; Morris, T.O. & McSpadden, S.B.
Partner: UNT Libraries Government Documents Department

Performance evaluation of bound diamond ring tools

Description: LLNL is collaborating with the Center for Optics Manufacturing (COM) and the American Precision Optics Manufacturers Association (APOMA) to optimize bound diamond ring tools for the spherical generation of high quality optical surfaces. An important element of this work is establishing an experimentally-verified link between tooling properties and workpiece quality indicators such as roughness, subsurface damage and removal rate. In this paper, we report on a standardized methodology for assessing ring tool performance and its preliminary application to a set of commercially-available wheels. Our goals are to (1) assist optics manufacturers (users of the ring tools) in evaluating tools and in assessing their applicability for a given operation, and (2) provide performance feedback to wheel manufacturers to help optimize tooling for the optics industry. Our paper includes measurements of wheel performance for three 2-4 micron diamond bronze-bond wheels that were supplied by different manufacturers to nominally- identical specifications. Preliminary data suggests that the difference in performance levels among the wheels were small.
Date: July 14, 1995
Creator: Piscotty, M.A.; Taylor, J.S. & Blaedel, K.L.
Partner: UNT Libraries Government Documents Department

Value of Distributed Preprocessing of Biomass Feedstocks to a Bioenergy Industry

Description: Biomass preprocessing is one of the primary operations in the feedstock assembly system and the front-end of a biorefinery. Its purpose is to chop, grind, or otherwise format the biomass into a suitable feedstock for conversion to ethanol and other bioproducts. Many variables such as equipment cost and efficiency, and feedstock moisture content, particle size, bulk density, compressibility, and flowability affect the location and implementation of this unit operation. Previous conceptual designs show this operation to be located at the front-end of the biorefinery. However, data are presented that show distributed preprocessing at the field-side or in a fixed preprocessing facility can provide significant cost benefits by producing a higher value feedstock with improved handling, transporting, and merchandising potential. In addition, data supporting the preferential deconstruction of feedstock materials due to their bio-composite structure identifies the potential for significant improvements in equipment efficiencies and compositional quality upgrades. Theses data are collected from full-scale low and high capacity hammermill grinders with various screen sizes. Multiple feedstock varieties with a range of moisture values were used in the preprocessing tests. The comparative values of the different grinding configurations, feedstock varieties, and moisture levels are assessed through post-grinding analysis of the different particle fractions separated with a medium-scale forage particle separator and a Rototap separator. The results show that distributed preprocessing produces a material that has bulk flowable properties and fractionation benefits that can improve the ease of transporting, handling and conveying the material to the biorefinery and improve the biochemical and thermochemical conversion processes.
Date: July 1, 2006
Creator: Wright, Christopher T
Partner: UNT Libraries Government Documents Department