West Lafayette, IN, United States
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Guo Y.,M4 Sciences LLC | Lee S.E.,M4 Sciences LLC | Mann J.B.,M4 Sciences LLC
Journal of Manufacturing Science and Engineering, Transactions of the ASME | Year: 2017

A new electromechanical modulation system designed with piezoelectric stacks for both linear actuation and force sensing functions is described. The system can be adapted for modulationassisted machining (MAM) drilling processes where a lowfrequency (<1000 Hz) sinusoidal oscillation is superimposed directly onto the drilling process, such that the feedrate is modulated. A series of drilling experiments were conducted in Ti6Al4V, 17-4 steel, and Al6061 with the system installed on a CNC machine. The drill displacement, thrust force, and chip morphology were characterized across a range of conventional and MAM drilling conditions. The mechanical response (stiffness) of the system agrees with the design specifications. The system offers new capabilities to control the modulation frequency and amplitude in MAM drilling, while simultaneously measuring the drilling thrust force in real time. The force sensing function enables detection of the intermittent separations between the drill tip and the workpiece surface (occurrence of discrete cutting), providing a method to prescribe and control the modulation conditions necessary for effective MAM drilling. Opportunities for force feedback control and process monitoring in MAM drilling processes are discussed. While the system described emphasizes MAM drilling, the capabilities can be extended to other machining processes. © Copyright 2017 by ASME.

Sagapuram D.,Purdue University | Yeung H.,Purdue University | Guo Y.,M4 Sciences LLC | Mahato A.,Purdue University | And 4 more authors.
CIRP Annals - Manufacturing Technology | Year: 2015

Large strain plastic flow in cutting of metals is studied at multiple length scales using high-speed imaging and marker techniques, complemented by particle image velocimetry and electron microscopy. Quantitative analysis of streak-lines, strain fields and microstructure, shows the flow to be often unsteady. Instabilities such as segmentation driven by ductile fracture, vortex-like flow in ductile metals, and shear banding in low-thermal diffusivity systems are elucidated using direct observations. A constrained-cutting process is demonstrated for suppressing the instabilities and unsteady flow. © 2015 CIRP.

Mann J.B.,M4 Sciences LLC | Saldana C.,Pennsylvania State University
Transactions of the North American Manufacturing Research Institution of SME | Year: 2013

The present study characterizes the effects of modulation amplitude on forces and specific energies in machining of AA6061-T6. These effects are correlated with tool load duty cycles that vary directly with modulation amplitude. Closed-form expressions were derived to evaluate fraction of time spent cutting in the presence of modulation. The duty cycle ratio ranges from 1 to 0.5 depending on the modulation amplitude used for a specific modulation frequency and spindle frequency combination. When the duty cycle decreased, average machining forces rise while the apparent average machining forces and specific energies both decrease. Use of apparent average machining forces for describing tool load profiles was found to be tenuous as maximum load on the tool actually increases in the presence of modulation. The ability to modify the fraction of time spent cutting has direct implications for affecting changes in thermal dissipation and interface lubrication, which are important in characterizing the effects of machining conditions on surface integrity and cutting tool performance.

Mahato A.,Purdue University | Guo Y.,M4 Sciences LLC | Sundaram N.K.,Indian Institute of Science | Chandrasekar S.,Purdue University
Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences | Year: 2014

Using high-resolution, in situ imaging of a hard, wedge-shaped model asperity sliding against a metal surface, we demonstrate a newmechanism for particle formation and delamination wear. Damage to the residual surface is caused by the occurrence of folds on the free surface of the prow-shaped region ahead of the wedge. This damage manifests itself as shallow crack-like features and surface tears, which are inclined at very acute angles to the surface. The transformation of folds into cracks, tears and particles is directly captured. Notably, a single sliding pass is sufficient to damage the surface, and subsequent passes result in the generation of platelet-like wear particles. Tracking the folding process at every stage from surface bumps to folds to cracks/tears/particles ensures that there is no ambiguity in capturing the mechanism of wear. Because fold formation and consequent delamination are quite general, our findings have broad applicability beyond wear itself, including implications for design of surface generation and conditioning processes. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

Guo Y.,M4 Sciences LLC | Compton W.D.,Purdue University | Chandrasekar S.,Purdue University
Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences | Year: 2015

The flow dynamics, deformation fields and chip-particle formation in cutting and sliding of metals are analysed, in situ, using high-speed imaging and particle image velocimetry. The model system is a brass workpiece loaded against a wedge indenter at low speeds. At large negative rake angles, the flow is steady with a prow of material forming ahead of the indenter. There is no material removal and a uniformly strained layer develops on the workpiece surface - the pure sliding regime. When the rake angle is less negative, the flow becomes unsteady, triggered by formation of a crack on the prow free surface and material removal ensuing - the cutting regime. The strain on the prow surface at crack initiation is found to be constant. Chip morphologies, such as discrete particle, segmented chip and continuous chip with mesoscale roughness, are shown to arise from a universal mechanism involving propagation of the prow crack, but to different distances towards the indenter tip. The simple shear deformation in continuous chip formation shows small-angle oscillations also linked to the prow crack. Implications for material removal processes and ductile failure are discussed. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

Mann J.B.,Purdue University | Mann J.B.,M4 Sciences LLC | Guo Y.,Purdue University | Saldana C.,Purdue University | And 3 more authors.
Tribology International | Year: 2011

The controlled application of low-frequency modulation to machining Modulation Assisted Machining (MAM) is shown to effect discrete chip formation and disrupt the severe contact condition at the toolchip interface. This enables chips of different morphologies, including discrete-particle like chips, to be created, and prescription of the machined surface texture. A model for MAM is used to describe chip formation regimes and textures. Benefits include improved chip management; enhanced lubrication; reduction of tool wear; and enhanced material removal rates. Prototype implementation of MAM in processes such as drilling and turning is described in case studies. © 2011 Elsevier Ltd. All rights reserved.

Agency: Department of Defense | Branch: Army | Program: STTR | Phase: Phase I | Award Amount: 99.89K | Year: 2010

This STTR project seeks to develop a new manufacturing system for large-scale, low-cost production of bulk ultrafine grained (UFG) or nanostructured metals in plate, sheet or bar forms. These capabilities will be based on scale-up of a new class of machining-based processes called large strain extrusion machining (LSEM) that has been effective at creating high strength, nanoscale microstructures in a variety of alloy systems. Combining the strengths of M4 Sciences and Purdue University, the project will build on findings that hybrid machining-extrusion processes, based on LSEM constrained chip formation, offer a transformative approach for overcoming the limitations to large-scale production of UFG alloys by Severe Plastic Deformation (SPD) processing. The new hybrid machining processes can impart the large levels of plastic strain needed to effect grain refinement under controlled conditions, while simultaneously providing unprecedented control of the resulting bulk form (size and shape). Based on a strong foundation of preliminary work and intellectual property development, the project seeks to demonstrate LSEM of 4340 steel alloy, integrating systematic processing studies, material characterization, and analysis of energy, cost and equipment requirements.

Agency: National Science Foundation | Branch: | Program: SBIR | Phase: Phase I | Award Amount: 199.99K | Year: 2010

This Small Business Innovation Research (SBIR) Phase I project will demonstrate a new way to produce metal fibers in materials such as titanium and aluminum alloys using a special machining process known as Modulation-Assisted Machining or MAM. The most widely adopted method for producing metal fibers is a multi-step wire drawing process, where small diameter wires are drawn from a metal billet and subsequently cut into discrete lengths. However, this process is limited to materials that can be drawn into wires and the capital equipment costs are high and related infrastructure requirements complex. The MAM process has evolved from research at Purdue University and has demonstrated the potential to radically change the capacity and flexibility of metal fiber production while simultaneously achieving a lower cost. By using the MAM process, fibers can be machined directly from metal bars. The project objectives include: 1) Produce aluminum alloy and titanium fibers using MAM; 2) Characterize the effects of MAM parameters on fiber geometry and microstructure; 3) Measure the strength of fibers produced by MAM; and, 4) demonstrate fiber production scale-up concepts. This is expected to enhance the application of MAM to a viable process for production of metal fibers. The broader impact/commercial potential of this project is that MAM processes will enable a method for production of metal fibers in virtually any metal alloy system. MAM could offer a new, low-cost method to produce fibers that are difficult or impossible to create using existing technology. The commercial potential for this project lies in the design and development of special modulation devices that adapt MAM technology for fiber-making using a CNC machine tool rather than a complex manufacturing plant. The extension of MAM technology into materials production will increase the market space for M4 Sciences products and increase commercial and research activity in the total market. Increased commercial impact also lies in the development of advanced metal fiber materials produced by MAM. These new metal fibers are expected to lead to commercial opportunities for the company's modulation devices for the production of metal fiber-based products and composite material systems that improve our quality of life. MAM could transform current machining technology from a process traditionally used to produce discrete parts with specific geometry to a process that produces advanced materials. Equally important, the proposed research will further the understanding of the effects of modulation on energy efficiency of machining processes.

M4 Sciences LLC | Date: 2013-11-05

Assemblies, apparatus, and methods are described for designing modulation tool holder assemblies and installations for modulation-assisted machining, and, in particular, for rotating machining applications that benefit from the sinusoidal modulation motion while cutting fluids are simultaneously applied through the tool. In addition, the design of rotating modulation tool holder assemblies and systems is described. In a tool holder assembly for modulation in a rotating spindle, the electric power and/or control signals are transferred from an external source to the modulation tool holder assembly installed in the rotating machine spindle. Similarly, the high-pressure cutting fluid is transferred from a stationary source to the rotating tool holder assembly for modulation.

M4 Sciences LLC | Date: 2010-05-18

electro-mechanical drilling devices for use with lathes; electro-mechanical tool holders for industrial machines; electronically controlled industrial machines for producing very small parts; Machine tool holders; Machines and machine tools for the cutting and forming of materials; Metalworking machine tools; Tool holders for metalworking machines; Machine tool holders for use in forming particle sized parts; Machines and machine tools for the cutting and forming of materials into particle sized parts; Metalworking machine tools for use in forming particle sized parts. electronic controllers for industrial machines. design, development and engineering services for others in the field of precision machining processes, tools, and tool holders.

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