Frank Pfefferkorn - Academia.edu (original) (raw)

Papers by Frank Pfefferkorn

Thermal Spray 2021: Proceedings from the International Thermal Spray Conference

Cold spray deposition is being investigated for mitigation of chloride-induced stress corrosion c... more Cold spray deposition is being investigated for mitigation of chloride-induced stress corrosion cracking (CISCC) in dry cask storage systems (DCSS) for spent nuclear fuel. Welded regions of austenitic stainless-steel canisters in DCSS are under tensile stress and susceptible to environmental chloride corrosion, which can potentially lead to the formation of CISCC. The low thermal input and high throughput nature of cold spraying make it a viable repair and mitigation option for managing potential CISCC. Cold spray coatings are under compressive stress and act as a barrier in Cl-rich environments. Characterization data including microstructure, hardness, and corrosion resistance are presented for cold spray coatings on stainless steel substrates.

Journal of Laser Applications

The field of laser polishing has grown to include many strategies and materials, but several barr... more The field of laser polishing has grown to include many strategies and materials, but several barriers remain to widespread commercialization of this technology, one being a lack of predictive capability of how laser polishing affects part edge features. The objective of the present work is to present a method of predicting this change in edge geometry and compare the results with experimental observation of laser polishing on blunt, square, and sharp edges. This was done by measuring the edge geometry before and after polishing using optical focus-variation metrology and comparing this with a prediction from a laser polishing simulation. The results showed good agreement in the edge rounding behavior between simulation and experiment except for an asymmetry of the observed polished edge at higher power that is not captured in the capillary smoothing model. This indicates that the present model can act as a good model for predicting edge rounding at lower power conditions, but additional capability in predicting material buildup and displacement at higher power needs to be added for fully pre-dictive capability. V C 2017 Laser Institute of America. [http://dx.doi.org/10.2351/1.4976560]

Journal of Manufacturing Science and Engineering

Hybrid welding/joining of lightweight metals to carbon fiber reinforced polymers (CFRPs) typicall... more Hybrid welding/joining of lightweight metals to carbon fiber reinforced polymers (CFRPs) typically relies on the adhesive bond created when the molten polymer matrix hardens in contact with the metallic surface. It is hypothesized that these bonds can be improved upon by fully displacing the polymer and infiltrating the carbon fibers with the metallic constituent to create load-bearing fibers that bridge the two materials. Friction stir welding (FSW) holds potential to melt and displace the polymer matrix, plasticize the metal constituent, and force the plasticized metal to flow around the fibers. Preliminary investigations were performed by FSW in AA 6061-T6 plates sandwiched against dry carbon fiber bundles. The FSW process plasticizes the aluminum while applying pressure, forcing the material to flow around the fibers. Cross-sectional images of the samples were used to measure the distance of infiltration of the aluminum into the carbon fiber bed. A fiber infiltration model previ...

International Journal of Heat and Mass Transfer, May 1, 2005

A three-dimensional, unsteady heat transfer model has been developed for predicting the temperatu... more A three-dimensional, unsteady heat transfer model has been developed for predicting the temperature field in partially-stabilized zirconia (PSZ) undergoing laser-assisted machining. The semi-transparent PSZ is treated as optically thick within a spectral band from approximately 0.5 to 8μm. After comparing the diffusion approximation and the discrete ordinates method for predicting internal radiative transfer, suitability of the diffusion approximation is established from a comparison of model predictions with surface temperature measurements. The temperature predictions are in good agreement with measured values during machining. Parametric calculations reveal that laser power and feedrate have the greatest effect on machining temperatures.

Journal of Manufacturing Science and Engineering, 2009

The precision of parts created by microfabrication processes is limited by surface roughness. The... more The precision of parts created by microfabrication processes is limited by surface roughness. Therefore, as a means of improving surface roughness, pulsed laser micropolishing on nickel was examined numerically and experimentally. A one-dimensional finite element method model was used to estimate the melt depth and duration for single 50–300 ns laser pulses. The critical frequency was introduced to predict the effectiveness of polishing in the spatial frequency domain. A 1064 nm Nd:YAG laser with 300 ns pulses was used to experimentally investigate pulsed laser polishing on microfabricated nickel samples with microscale line features. A microfabricated sample with 2.5 μm wide and 0.2 μm high lines spaced 5 μm apart and one with 5 μm wide and 0.38 μm high lines spaced 10 μm apart were polished with 300 ns long pulses of 47.2 J/cm2 and 44.1 J/cm2 fluences, respectively. The critical frequency for these experimental conditions was predicted and compared with the reduction in the average surface roughness measured for samples with two different spatial frequency contents. The average surface roughness of 5 μm and 10 μm wavelength line features were reduced from 0.112 μm to 0.015 μm and from 0.112 μm to 0.059 μm, respectively. Four regimes of pulsed laser micropolishing are identified as a function of laser fluence for a given pulse width: (1) at low fluences no polishing occurs due to insufficient melting, (2) moderate fluences allow sufficient melt time for surface wave damping and significant smoothing occurs, (3) increasing fluence reduces smoothing, and (4) high fluences cause roughening due to large recoil pressure and ablation. Significant improvements in average surface roughness can be achieved by pulsed laser micropolishing if the dominant frequency content of the original surface features is above the critical spatial frequency for polishing.

Journal of Micro and Nano Manufacturing, Jun 1, 2014

Http Dx Doi Org 10 1080 08916159708946549, Apr 23, 2007

ABSTRACT

Journal of Manufacturing Science and Engineering, 2004

Laser-assisted machining (LAM) of magnesia-partially-stabilized zirconia (PSZ) is investigated to... more Laser-assisted machining (LAM) of magnesia-partially-stabilized zirconia (PSZ) is investigated to determine the effect of heating on machinability, as determined by tool wear, cutting energy, surface integrity, and material removal mechanisms. It is found that PSZ can be successfully machined with a polycrystalline cubic boron nitride tool and that tool life increases with material removal temperature up to a maximum of 121 minutes. The benefit of laser-assistance in material removal is also demonstrated by the 2.5 fold decrease in the specific cutting energy with increased temperature. It is shown surface roughness varies significantly with tool wear with little dependence on cutting temperature unlike in LAM of other ceramics. Evidence of mixed brittle and ductile material removal mechanisms is presented, and the optimum condition within the test matrix is established.

Journal of Manufacturing Processes, 2009

ABSTRACT Pulsed laser micro-polishing (PLμP) was investigated as a method to reduce the surface r... more ABSTRACT Pulsed laser micro-polishing (PLμP) was investigated as a method to reduce the surface roughness of micro-milled Ti6Al4V samples. Thermal modeling was presented to estimate the melt depth and duration caused by a single laser pulse ranging from 50–1000 ns on a flat Ti6Al4V surface. Predictions of the spatial frequency domain that experiences significant amplitude reductions (i.e., polishing) agrees well with experiments. Polishing was performed using a 1064 nm Nd:YAG laser in Q-switch mode at a repetition rate of 4 kHz, 50–70 μm laser spot size, and pulse duration of 650 ns. Surface cracking was observed when polishing the samples in air, a result of oxides forming on the workpiece surface. To prevent oxidation during the laser polishing process Argon, an inert shielding gas that is heavier than air, was employed. Polishing results with Argon shielding demonstrated a reduction in average surface roughness by a factor of two. Two-dimensional polishing is demonstrated using a computer controlled optical scan head. In addition, the PLμP process was used to effectively reduce surface scratches on Ti6Al4V samples.

Journal of Manufacturing Science and Engineering, 2009

The objective of this work was to improve our understanding of pulsed laser micropolishing (PLμP)... more The objective of this work was to improve our understanding of pulsed laser micropolishing (PLμP) by studying the effects of laser pulse length and feed rate (pulses per millimeter) on surface roughness. PLμP experiments were conducted with a multimode neodymium-doped yttrium aluminum garnet (Nd:YAG) laser (1064 nm wavelength) that was focused down to approximately 50 μm diameter and scanned over the stationary workpiece surface. Simulation results presented here and previous work suggest that longer laser pulses result in smoother surfaces. Results on microfabricated nickel samples using laser pulse durations of 300 ns and 650 ns test this hypothesis. Polishing with 300 ns and 650 ns pulse durations results in an average surface roughness of 66 nm and 47 nm, respectively; reductions of 30% and 50% compared with the original surface. Furthermore, PLμP is shown to introduce a minor artifact on the sample surface whose spatial frequency (1/mm) is directly related to the laser feed rate (pulses/mm).

Manufacturing Letters, 2015

The objective of the work is the reduction and eventual avoidance of post welding inspections tha... more The objective of the work is the reduction and eventual avoidance of post welding inspections that are currently needed to ensure defect-free welds. An analytical thermal model of the FSW process along with an analytical disturbance model is developed. This disturbance model relates defect formation to variations in the measured temperature and is based on experimental process identification. A dynamic disturbance observer computes an estimate of the disturbance signal, which is further processed in order to provide information about the presence of defects along the weld. Experiments for one kind of disturbance verify that the observer shows good tracking behavior.

ASME 2007 International Manufacturing Science and Engineering Conference, 2007

Laser assisted machining is an alternative to conventional machining of hard and/or difficult-to-... more Laser assisted machining is an alternative to conventional machining of hard and/or difficult-to-process materials which involves pre-heating of a focused area with a laser beam over the surface of the workpiece to cause localized thermal softening along the path of the cutting action. The main advantage that laser assisted machining has over conventional machining is the increased material removal rate and productivity. Laser assisted micromilling is a scaled down derivative of laser assisted machining assuming that the process effectiveness potentially exists at the meso/micro scale. It is well-known that continuous-wave (c.w.) lasers generate a wide and deep heat affected zone, and can cause microstructure alterations, potentially making laser assistance counter-productive at the meso/micro scale. The novel use of a pulsed laser in assisting micromilling enables processing of die/mold metal alloys that are typically hard and/or difficult-to-process in micro scale, while reducing the heat affected zone. A fairly innovative technique is introduced by thermally softening only the focused microscale area of the work material with induced heat from a pulsed laser, and material removal is performed immediately with micro mechanical end milling. The focus of this paper is to present a fundamental understanding of the pulsed laser assisted micromilling (PLAM), in particular, to investigate the influence of pulsing on microscale localized thermal softening by coupling with the finite element simulation of the micromilling process. Experiments and Finite element method-based process simulations for micromilling of AISI 4340 steel with and without the laser assistance are conducted to study the influence of the pulsed laser thermal softening on the reduction in cutting forces and its influence on the temperature rise in the cutting tool.

Proceedings - Frontiers in Education Conference

Thermodynamics, fluid mechanics, and heat transfer comprise the thermal stem, which, along with t... more Thermodynamics, fluid mechanics, and heat transfer comprise the thermal stem, which, along with the mechanical systems stem, is required for the BS degree in Mechanical Engineering. Traditionally, each of these subjects is covered in a separate course. A set of concept inventories that cover the fundamental concepts in the Thermal Science subject areas have been developed. The inventories have been given in courses at the University of Wisconsin and other universities over the last three semesters. An analysis of the results from the inventories and the development of a second version of one of the inventories are reported in this Work in Progress. Index Terms-assessment, concept inventories, teaching methods.

International Journal of Engineering Education

This work describes the introduction of microscale manufacturing education into the mechanical en... more This work describes the introduction of microscale manufacturing education into the mechanical engineering curriculum at the Purdue University. Lectures and laboratories on microscale manufacturing are integrated into an undergraduate technical elective course, Principles and Practices of Manufacturing Processes. Three one-hour lectures introduce fundamental microfabrication processes with a focus on soft lithography. Two microfabrication laboratories have been designed, developed, and implemented using a newly developed pilot facility within Purdue's Multiscale Manufacturing Center (MMC). Through the laboratories, students gain hands-on microfabrication experience and achieve devices with features as small as 10 "m. We expect this work will serve as a model to establish similar manufacturing educational laboratories at other institutions.

2015 ASEE Annual Conference and Exposition Proceedings, 2015

Madison. He has been an instructor in the UW-Madison College of Engineering since 1988. He holds ... more Madison. He has been an instructor in the UW-Madison College of Engineering since 1988. He holds both BS and MS degrees from the UW-Madison in Engineering Mechanics. He has taught undergraduate classes in Capstone Design, Geometric Modeling, Computer-Aided Design, Product Dissection, Product Redesign and Prototype Fabrication, and Engineering Graphics. He has worked as a mechanical designer in industry and has been teaching capstone design at the UW-Madison since 1996. He has created and taught industrial outreach courses in Geometric Dimensioning and Tolerancing (GD&T) and co-manages the Metrology Lab in the department of Mechanical Engineering. He also served as a member of the ASME Y14.41 SubCommittee charged with the development of standards for the inclusion of Geometric Dimensioning and Tolerancing specifications within solid model product definitions.

A hybrid surface treatment method is presented on S7 tool steel by alloying the surface layer wit... more A hybrid surface treatment method is presented on S7 tool steel by alloying the surface layer with boron and following with pulsed laser micro polishing (PLuP). The objective of the hybrid approach is twofold: First, surface alloying changes the properties of the surface layer that are relevant to the PLuP process (e.g. liquid metal density, viscosity, and surface tension). This allows more control over the laser polishing phenomena for better smoothing. Second, surface alloying and laser melting/quenching is proposed as a novel method of creating amorphous surface coatings. In this work, boron was introduced into the surface of an S7 tool steel sample using pack cementation. This sample was then ground on a bias to create a flat surface with a gradient in chemical composition and this surface was laser melted. The effect of this variation in alloy chemistry on the surface features created by pulsed laser melting is presented.

Thermal Spray 2021: Proceedings from the International Thermal Spray Conference

Cold spray deposition is being investigated for mitigation of chloride-induced stress corrosion c... more Cold spray deposition is being investigated for mitigation of chloride-induced stress corrosion cracking (CISCC) in dry cask storage systems (DCSS) for spent nuclear fuel. Welded regions of austenitic stainless-steel canisters in DCSS are under tensile stress and susceptible to environmental chloride corrosion, which can potentially lead to the formation of CISCC. The low thermal input and high throughput nature of cold spraying make it a viable repair and mitigation option for managing potential CISCC. Cold spray coatings are under compressive stress and act as a barrier in Cl-rich environments. Characterization data including microstructure, hardness, and corrosion resistance are presented for cold spray coatings on stainless steel substrates.

Journal of Laser Applications

The field of laser polishing has grown to include many strategies and materials, but several barr... more The field of laser polishing has grown to include many strategies and materials, but several barriers remain to widespread commercialization of this technology, one being a lack of predictive capability of how laser polishing affects part edge features. The objective of the present work is to present a method of predicting this change in edge geometry and compare the results with experimental observation of laser polishing on blunt, square, and sharp edges. This was done by measuring the edge geometry before and after polishing using optical focus-variation metrology and comparing this with a prediction from a laser polishing simulation. The results showed good agreement in the edge rounding behavior between simulation and experiment except for an asymmetry of the observed polished edge at higher power that is not captured in the capillary smoothing model. This indicates that the present model can act as a good model for predicting edge rounding at lower power conditions, but additional capability in predicting material buildup and displacement at higher power needs to be added for fully pre-dictive capability. V C 2017 Laser Institute of America. [http://dx.doi.org/10.2351/1.4976560]

Journal of Manufacturing Science and Engineering

Hybrid welding/joining of lightweight metals to carbon fiber reinforced polymers (CFRPs) typicall... more Hybrid welding/joining of lightweight metals to carbon fiber reinforced polymers (CFRPs) typically relies on the adhesive bond created when the molten polymer matrix hardens in contact with the metallic surface. It is hypothesized that these bonds can be improved upon by fully displacing the polymer and infiltrating the carbon fibers with the metallic constituent to create load-bearing fibers that bridge the two materials. Friction stir welding (FSW) holds potential to melt and displace the polymer matrix, plasticize the metal constituent, and force the plasticized metal to flow around the fibers. Preliminary investigations were performed by FSW in AA 6061-T6 plates sandwiched against dry carbon fiber bundles. The FSW process plasticizes the aluminum while applying pressure, forcing the material to flow around the fibers. Cross-sectional images of the samples were used to measure the distance of infiltration of the aluminum into the carbon fiber bed. A fiber infiltration model previ...

International Journal of Heat and Mass Transfer, May 1, 2005

A three-dimensional, unsteady heat transfer model has been developed for predicting the temperatu... more A three-dimensional, unsteady heat transfer model has been developed for predicting the temperature field in partially-stabilized zirconia (PSZ) undergoing laser-assisted machining. The semi-transparent PSZ is treated as optically thick within a spectral band from approximately 0.5 to 8μm. After comparing the diffusion approximation and the discrete ordinates method for predicting internal radiative transfer, suitability of the diffusion approximation is established from a comparison of model predictions with surface temperature measurements. The temperature predictions are in good agreement with measured values during machining. Parametric calculations reveal that laser power and feedrate have the greatest effect on machining temperatures.

Journal of Manufacturing Science and Engineering, 2009

The precision of parts created by microfabrication processes is limited by surface roughness. The... more The precision of parts created by microfabrication processes is limited by surface roughness. Therefore, as a means of improving surface roughness, pulsed laser micropolishing on nickel was examined numerically and experimentally. A one-dimensional finite element method model was used to estimate the melt depth and duration for single 50–300 ns laser pulses. The critical frequency was introduced to predict the effectiveness of polishing in the spatial frequency domain. A 1064 nm Nd:YAG laser with 300 ns pulses was used to experimentally investigate pulsed laser polishing on microfabricated nickel samples with microscale line features. A microfabricated sample with 2.5 μm wide and 0.2 μm high lines spaced 5 μm apart and one with 5 μm wide and 0.38 μm high lines spaced 10 μm apart were polished with 300 ns long pulses of 47.2 J/cm2 and 44.1 J/cm2 fluences, respectively. The critical frequency for these experimental conditions was predicted and compared with the reduction in the average surface roughness measured for samples with two different spatial frequency contents. The average surface roughness of 5 μm and 10 μm wavelength line features were reduced from 0.112 μm to 0.015 μm and from 0.112 μm to 0.059 μm, respectively. Four regimes of pulsed laser micropolishing are identified as a function of laser fluence for a given pulse width: (1) at low fluences no polishing occurs due to insufficient melting, (2) moderate fluences allow sufficient melt time for surface wave damping and significant smoothing occurs, (3) increasing fluence reduces smoothing, and (4) high fluences cause roughening due to large recoil pressure and ablation. Significant improvements in average surface roughness can be achieved by pulsed laser micropolishing if the dominant frequency content of the original surface features is above the critical spatial frequency for polishing.

Journal of Micro and Nano Manufacturing, Jun 1, 2014

Http Dx Doi Org 10 1080 08916159708946549, Apr 23, 2007

ABSTRACT

Journal of Manufacturing Science and Engineering, 2004

Laser-assisted machining (LAM) of magnesia-partially-stabilized zirconia (PSZ) is investigated to... more Laser-assisted machining (LAM) of magnesia-partially-stabilized zirconia (PSZ) is investigated to determine the effect of heating on machinability, as determined by tool wear, cutting energy, surface integrity, and material removal mechanisms. It is found that PSZ can be successfully machined with a polycrystalline cubic boron nitride tool and that tool life increases with material removal temperature up to a maximum of 121 minutes. The benefit of laser-assistance in material removal is also demonstrated by the 2.5 fold decrease in the specific cutting energy with increased temperature. It is shown surface roughness varies significantly with tool wear with little dependence on cutting temperature unlike in LAM of other ceramics. Evidence of mixed brittle and ductile material removal mechanisms is presented, and the optimum condition within the test matrix is established.

Journal of Manufacturing Processes, 2009

ABSTRACT Pulsed laser micro-polishing (PLμP) was investigated as a method to reduce the surface r... more ABSTRACT Pulsed laser micro-polishing (PLμP) was investigated as a method to reduce the surface roughness of micro-milled Ti6Al4V samples. Thermal modeling was presented to estimate the melt depth and duration caused by a single laser pulse ranging from 50–1000 ns on a flat Ti6Al4V surface. Predictions of the spatial frequency domain that experiences significant amplitude reductions (i.e., polishing) agrees well with experiments. Polishing was performed using a 1064 nm Nd:YAG laser in Q-switch mode at a repetition rate of 4 kHz, 50–70 μm laser spot size, and pulse duration of 650 ns. Surface cracking was observed when polishing the samples in air, a result of oxides forming on the workpiece surface. To prevent oxidation during the laser polishing process Argon, an inert shielding gas that is heavier than air, was employed. Polishing results with Argon shielding demonstrated a reduction in average surface roughness by a factor of two. Two-dimensional polishing is demonstrated using a computer controlled optical scan head. In addition, the PLμP process was used to effectively reduce surface scratches on Ti6Al4V samples.

Journal of Manufacturing Science and Engineering, 2009

The objective of this work was to improve our understanding of pulsed laser micropolishing (PLμP)... more The objective of this work was to improve our understanding of pulsed laser micropolishing (PLμP) by studying the effects of laser pulse length and feed rate (pulses per millimeter) on surface roughness. PLμP experiments were conducted with a multimode neodymium-doped yttrium aluminum garnet (Nd:YAG) laser (1064 nm wavelength) that was focused down to approximately 50 μm diameter and scanned over the stationary workpiece surface. Simulation results presented here and previous work suggest that longer laser pulses result in smoother surfaces. Results on microfabricated nickel samples using laser pulse durations of 300 ns and 650 ns test this hypothesis. Polishing with 300 ns and 650 ns pulse durations results in an average surface roughness of 66 nm and 47 nm, respectively; reductions of 30% and 50% compared with the original surface. Furthermore, PLμP is shown to introduce a minor artifact on the sample surface whose spatial frequency (1/mm) is directly related to the laser feed rate (pulses/mm).

Manufacturing Letters, 2015

The objective of the work is the reduction and eventual avoidance of post welding inspections tha... more The objective of the work is the reduction and eventual avoidance of post welding inspections that are currently needed to ensure defect-free welds. An analytical thermal model of the FSW process along with an analytical disturbance model is developed. This disturbance model relates defect formation to variations in the measured temperature and is based on experimental process identification. A dynamic disturbance observer computes an estimate of the disturbance signal, which is further processed in order to provide information about the presence of defects along the weld. Experiments for one kind of disturbance verify that the observer shows good tracking behavior.

ASME 2007 International Manufacturing Science and Engineering Conference, 2007

Laser assisted machining is an alternative to conventional machining of hard and/or difficult-to-... more Laser assisted machining is an alternative to conventional machining of hard and/or difficult-to-process materials which involves pre-heating of a focused area with a laser beam over the surface of the workpiece to cause localized thermal softening along the path of the cutting action. The main advantage that laser assisted machining has over conventional machining is the increased material removal rate and productivity. Laser assisted micromilling is a scaled down derivative of laser assisted machining assuming that the process effectiveness potentially exists at the meso/micro scale. It is well-known that continuous-wave (c.w.) lasers generate a wide and deep heat affected zone, and can cause microstructure alterations, potentially making laser assistance counter-productive at the meso/micro scale. The novel use of a pulsed laser in assisting micromilling enables processing of die/mold metal alloys that are typically hard and/or difficult-to-process in micro scale, while reducing the heat affected zone. A fairly innovative technique is introduced by thermally softening only the focused microscale area of the work material with induced heat from a pulsed laser, and material removal is performed immediately with micro mechanical end milling. The focus of this paper is to present a fundamental understanding of the pulsed laser assisted micromilling (PLAM), in particular, to investigate the influence of pulsing on microscale localized thermal softening by coupling with the finite element simulation of the micromilling process. Experiments and Finite element method-based process simulations for micromilling of AISI 4340 steel with and without the laser assistance are conducted to study the influence of the pulsed laser thermal softening on the reduction in cutting forces and its influence on the temperature rise in the cutting tool.

Proceedings - Frontiers in Education Conference

Thermodynamics, fluid mechanics, and heat transfer comprise the thermal stem, which, along with t... more Thermodynamics, fluid mechanics, and heat transfer comprise the thermal stem, which, along with the mechanical systems stem, is required for the BS degree in Mechanical Engineering. Traditionally, each of these subjects is covered in a separate course. A set of concept inventories that cover the fundamental concepts in the Thermal Science subject areas have been developed. The inventories have been given in courses at the University of Wisconsin and other universities over the last three semesters. An analysis of the results from the inventories and the development of a second version of one of the inventories are reported in this Work in Progress. Index Terms-assessment, concept inventories, teaching methods.

International Journal of Engineering Education

This work describes the introduction of microscale manufacturing education into the mechanical en... more This work describes the introduction of microscale manufacturing education into the mechanical engineering curriculum at the Purdue University. Lectures and laboratories on microscale manufacturing are integrated into an undergraduate technical elective course, Principles and Practices of Manufacturing Processes. Three one-hour lectures introduce fundamental microfabrication processes with a focus on soft lithography. Two microfabrication laboratories have been designed, developed, and implemented using a newly developed pilot facility within Purdue's Multiscale Manufacturing Center (MMC). Through the laboratories, students gain hands-on microfabrication experience and achieve devices with features as small as 10 "m. We expect this work will serve as a model to establish similar manufacturing educational laboratories at other institutions.

2015 ASEE Annual Conference and Exposition Proceedings, 2015

Madison. He has been an instructor in the UW-Madison College of Engineering since 1988. He holds ... more Madison. He has been an instructor in the UW-Madison College of Engineering since 1988. He holds both BS and MS degrees from the UW-Madison in Engineering Mechanics. He has taught undergraduate classes in Capstone Design, Geometric Modeling, Computer-Aided Design, Product Dissection, Product Redesign and Prototype Fabrication, and Engineering Graphics. He has worked as a mechanical designer in industry and has been teaching capstone design at the UW-Madison since 1996. He has created and taught industrial outreach courses in Geometric Dimensioning and Tolerancing (GD&T) and co-manages the Metrology Lab in the department of Mechanical Engineering. He also served as a member of the ASME Y14.41 SubCommittee charged with the development of standards for the inclusion of Geometric Dimensioning and Tolerancing specifications within solid model product definitions.

A hybrid surface treatment method is presented on S7 tool steel by alloying the surface layer wit... more A hybrid surface treatment method is presented on S7 tool steel by alloying the surface layer with boron and following with pulsed laser micro polishing (PLuP). The objective of the hybrid approach is twofold: First, surface alloying changes the properties of the surface layer that are relevant to the PLuP process (e.g. liquid metal density, viscosity, and surface tension). This allows more control over the laser polishing phenomena for better smoothing. Second, surface alloying and laser melting/quenching is proposed as a novel method of creating amorphous surface coatings. In this work, boron was introduced into the surface of an S7 tool steel sample using pack cementation. This sample was then ground on a bias to create a flat surface with a gradient in chemical composition and this surface was laser melted. The effect of this variation in alloy chemistry on the surface features created by pulsed laser melting is presented.