Matching Items (7)
Filtering by

Clear all filters

156687-Thumbnail Image.png
Description
Additive manufacturing (AM) describes an array of methods used to create a 3D object layer by layer. The increasing popularity of AM in the past decade has been due to its demonstrated potential to increase design flexibility, produce rapid prototypes, and decrease material waste. Temporary supports are an

Additive manufacturing (AM) describes an array of methods used to create a 3D object layer by layer. The increasing popularity of AM in the past decade has been due to its demonstrated potential to increase design flexibility, produce rapid prototypes, and decrease material waste. Temporary supports are an inconvenient necessity in many metal AM parts. These sacrificial structures are used to fabricate large overhangs, anchor the part to the build substrate, and provide a heat pathway to avoid warping. Polymers AM has addressed this issue by using support material that is soluble in an electrolyte that the base material is not. In contrast, metals AM has traditionally approached support removal using time consuming, costly methods such as electrical discharge machining or a dremel.

This work introduces dissolvable supports to single- and multi-material metals AM. The multi-material approach uses material choice to design a functionally graded material where corrosion is the functionality being varied. The single-material approach is the primary focus of this thesis, leveraging already common post-print heat treatments to locally alter the microstructure near the surface. By including a sensitizing agent in the ageing heat treatment, carbon is diffused into the part decreasing the corrosion resistance to a depth equal to at least half the support thickness. In a properly chosen electrolyte, this layer is easily chemically, or electrochemically removed. Stainless steel 316 (SS316) and Inconel 718 are both investigated to study this process using two popular alloys. The microstructure evolution and corrosion properties are investigated for both. For SS316, the effect of applied electrochemical potential is investigated to describe the varying corrosion phenomena induced, and the effect of potential choice on resultant roughness. In summary, a new approach to remove supports from metal AM parts is introduced to decrease costs and further the field of metals AM by expanding the design space.
ContributorsLefky, Christopher (Author) / Hildreth, Owen (Thesis advisor) / Chawla, Nikhilesh (Committee member) / Azeredo, Bruno (Committee member) / Rykaczewski, Konrad (Committee member) / Nian, Qiong (Committee member) / Arizona State University (Publisher)
Created2018
134678-Thumbnail Image.png
Description
Many industries require workers in warehouse and stockroom environments to perform frequent lifting tasks. Over time these repeated tasks can lead to excess strain on the worker's body and reduced productivity. This project seeks to develop an exoskeletal wrist fixture to be used in conjunction with a powered exoskeleton arm

Many industries require workers in warehouse and stockroom environments to perform frequent lifting tasks. Over time these repeated tasks can lead to excess strain on the worker's body and reduced productivity. This project seeks to develop an exoskeletal wrist fixture to be used in conjunction with a powered exoskeleton arm to aid workers performing box lifting types of tasks. Existing products aimed at improving worker comfort and productivity typically employ either fully powered exoskeleton suits or utilize minimally powered spring arms and/or fixtures. These designs either reduce stress to the user's body through powered arms and grippers operated via handheld controls which have limited functionality, or they use a more minimal setup that reduces some load, but exposes the user's hands and wrists to injury by directing support to the forearm. The design proposed here seeks to strike a balance between size, weight, and power requirements and also proposes a novel wrist exoskeleton design which minimizes stress on the user's wrists by directly interfacing with the object to be picked up. The design of the wrist exoskeleton was approached through initially selecting degrees of freedom and a ROM (range of motion) to accommodate. Feel and functionality were improved through an iterative prototyping process which yielded two primary designs. A novel "clip-in" method was proposed to allow the user to easily attach and detach from the exoskeleton. Designs utilized a contact surface intended to be used with dry fibrillary adhesives to maximize exoskeleton grip. Two final designs, which used two pivots in opposite kinematic order, were constructed and tested to determine the best kinematic layout. The best design had two prototypes created to be worn with passive test arms that attached to the user though a specially designed belt.
ContributorsGreason, Kenneth Berend (Author) / Sugar, Thomas (Thesis director) / Holgate, Matthew (Committee member) / Mechanical and Aerospace Engineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2016-12
Description

3D printing prosthetics for amputees is an innovative opportunity to provide a lower cost and customized alternative to current technologies. Companies, such as E-NABLE and YouBionic are developing myoelectric prosthetics, electrically powered terminal devices activated by electromyography (EMG), for transradial amputees. Prosthetics that are 3D printed are less expensive for

3D printing prosthetics for amputees is an innovative opportunity to provide a lower cost and customized alternative to current technologies. Companies, such as E-NABLE and YouBionic are developing myoelectric prosthetics, electrically powered terminal devices activated by electromyography (EMG), for transradial amputees. Prosthetics that are 3D printed are less expensive for juvenile use, more sustainable, and more accessible for those without insurance. Although they are typically not outfitted with the same complex grip patterns or durability of a traditional myoelectric prosthetic, they offer a sufficient durability (withstanding up to 150 N on average) and allow for new opportunities in prosthetic development. Devils Prosthetics, a student research and development group associated with Engineering Projects in Community Service (EPICS), has investigated the benefits and pitfalls of utilizing polyethylene terephthalate glycol (PETG) for 3D printing prosthetics as well as combining a MyoWare EMG sensor with machine learning for optimal control of the prosthetic.

ContributorsGryskiewicz, Jarek (Author) / Alessio, Gabby (Co-author) / Hiramina, Jason (Co-author) / Schoepf, Jared (Thesis director) / Shimono, Satoshi (Committee member) / Nemgar, Noah (Committee member) / Barrett, The Honors College (Contributor) / Harrington Bioengineering Program (Contributor)
Created2023-05
Description

3D printing prosthetics for amputees is an innovative opportunity to provide a lower cost and customized alternative to current technologies. Companies, such as E-NABLE and YouBionic are developing myoelectric prosthetics, electrically powered terminal devices activated by electromyography (EMG), for transradial amputees. Prosthetics that are 3D printed are less expensive for

3D printing prosthetics for amputees is an innovative opportunity to provide a lower cost and customized alternative to current technologies. Companies, such as E-NABLE and YouBionic are developing myoelectric prosthetics, electrically powered terminal devices activated by electromyography (EMG), for transradial amputees. Prosthetics that are 3D printed are less expensive for juvenile use, more sustainable, and more accessible for those without insurance. Although they are typically not outfitted with the same complex grip patterns or durability of a traditional myoelectric prosthetic, they offer a sufficient durability (withstanding up to 150 N on average) and allow for new opportunities in prosthetic development. Devils Prosthetics, a student research and development group associated with Engineering Projects in Community Service (EPICS), has investigated the benefits and pitfalls of utilizing polyethylene terephthalate glycol (PETG) for 3D printing prosthetics as well as combining a MyoWare EMG sensor with machine learning for optimal control of the prosthetic.

ContributorsHiramine, Jason (Author) / Alessio, Gabriella (Co-author) / Gryskiewicz, Jarek (Co-author) / Schoepf, Jared (Thesis director) / Shimono, Satoshi (Committee member) / Nemgar, Noah (Committee member) / Barrett, The Honors College (Contributor) / Harrington Bioengineering Program (Contributor) / School of Mathematical and Statistical Sciences (Contributor)
Created2023-05
Description

As a result of the increase of pollution related to industrialization in Vietnam, acid rain has become a prevalent issue for Vietnamese farmers who are forced to rinse their crops – risking damage due to overwatering and poor harvest. Thus, the team was motivated to develop a solution to harmful

As a result of the increase of pollution related to industrialization in Vietnam, acid rain has become a prevalent issue for Vietnamese farmers who are forced to rinse their crops – risking damage due to overwatering and poor harvest. Thus, the team was motivated to develop a solution to harmful impacts of acidic rainwater by creating a system with the ability to capture rainwater and determine its level of acidity in order to optimize the crop watering process, and promote productive crops. By conducting preliminary research on rainfall and tropical climate in Vietnam, existing products on the market, and pH sensors for monitoring and device material, the team was able to design a number of devices to collect, store, and measure the pH of rainwater. After developing a number of initial design requirements based on the needs of the farmers, a final prototype was developed using the best aspects of each initial design. Tests were conducted with varying structural and aqueous materials to represent a broad range of environmental conditions. While the scope of the project was ultimately limited to prototyping purposes, the principles explored throughout this thesis project can successfully be applied to a fully-functioning production model available for commercial use on Vietnamese farms. Given more time for development, improvements would be made in the extent of materials tested, and the configuration of electronics and data acquisition, in order to further optimize the process of determining rainwater acidity.

ContributorsRuiz Vargas, Vianney (Author) / Borrel, Henri (Co-author) / Masterson, William (Co-author) / Sweis, Hannah (Co-author) / Schoepf, Jared (Thesis director) / Grewal, Anoop (Committee member) / Barrett, The Honors College (Contributor) / Mechanical and Aerospace Engineering Program (Contributor) / School of International Letters and Cultures (Contributor)
Created2023-05
Description

3D printing prosthetics for amputees is an innovative opportunity to provide a lower cost and customized alternative to current technologies. Companies, such as E-NABLE and YouBionic are developing myoelectric prosthetics, electrically powered terminal devices activated by electromyography (EMG), for transradial amputees. Prosthetics that are 3D printed are less expensive for

3D printing prosthetics for amputees is an innovative opportunity to provide a lower cost and customized alternative to current technologies. Companies, such as E-NABLE and YouBionic are developing myoelectric prosthetics, electrically powered terminal devices activated by electromyography (EMG), for transradial amputees. Prosthetics that are 3D printed are less expensive for juvenile use, more sustainable, and more accessible for those without insurance. Although they are typically not outfitted with the same complex grip patterns or durability of a traditional myoelectric prosthetic, they offer a sufficient durability (withstanding up to 150 N on average) and allow for new opportunities in prosthetic development. Devils Prosthetics, a student research and development group associated with Engineering Projects in Community Service (EPICS), has investigated the benefits and pitfalls of utilizing polyethylene terephthalate glycol (PETG) for 3D printing prosthetics as well as combining a MyoWare EMG sensor with machine learning for optimal control of the prosthetic.

ContributorsAlessio, Gabriella (Author) / Gryskiewicz, Jarek (Co-author) / Hiramine, Jason (Co-author) / Schoepf, Jared (Thesis director) / Shimono, Satoshi (Committee member) / Nemgar, Noah (Committee member) / Barrett, The Honors College (Contributor) / Harrington Bioengineering Program (Contributor) / College of Integrative Sciences and Arts (Contributor)
Created2023-05
Description
Layer-wise extrusion of soft-solid like cement pastes and mortars is commonly used in 3D printing of concrete. Rheological and mechanical characterization of the printable binder for on-demand flow and subsequent structuration is a critical challenge. This research is an effort to understand the mechanics of cementitious binders as soft solids

Layer-wise extrusion of soft-solid like cement pastes and mortars is commonly used in 3D printing of concrete. Rheological and mechanical characterization of the printable binder for on-demand flow and subsequent structuration is a critical challenge. This research is an effort to understand the mechanics of cementitious binders as soft solids in the fresh state, towards establishing material-process relationships to enhance print quality. This study introduces 3D printable binders developed based on rotational and capillary rheology test parameters, and establish the direct influence of packing coefficients, geometric ratio, slip velocities, and critical print velocities on the extrudate quality. The ratio of packing fraction to the square of average particle diameter (0.01-0.02), and equivalent microstructural index (5-20) were suitable for printing, and were directly related to the cohesion and extrusional yield stress of the material. In fact, steady state pressure for printing (30-40 kPa) is proportional to the extrusional yield stress, and increases with the geometric ratio (0-60) and print velocity (5-50 mm/s). Higher print velocities results in higher wall shear stresses and was exponentially related to the slip layer thickness (estimated between 1-5μ), while the addition of superplasticizers improve the slip layer thickness and the extrudate flow. However, the steady state pressure and printer capacity limits the maximum print velocity while the deadzone length limits the minimum velocity allowable (critical velocity regime) for printing. The evolution of buildability with time for the fresh state mortars was characterized with digital image correlation using compressive strain and strain rate in printed layers. The fresh state characteristics (interlayer and interfilamentous) and process parameters (layer height and fiber dimensions) influence the hardened mechanical properties. A lower layer height generally improves the mechanical properties and slight addition of fiber (up to 0.3% by volume) results in a 15-30% increase in the mechanical properties. 3D scanning and point-cloud analysis was also used to assess the geometric tolerance of a print based on mean error distances, print accuracy index, and layer-wise percent overlap. The research output will contribute to a synergistic material-process design and development of test methods for printability in the context of 3D printing of concrete.
ContributorsAmbadi Omanakuttan Nair, Sooraj Kumar (Author) / Neithalath, Narayanan (Thesis advisor) / Rajan, Subramaniam (Committee member) / Mobasher, Barzin (Committee member) / Hoover, Christian (Committee member) / Chawla, Nikhilesh (Committee member) / Arizona State University (Publisher)
Created2021