Mechanical Engineering Commons^™

Analysis Of Variable Insensitive Friction Stir Welding Parameters, Robert L. Marrero Jr

LSU New Orleans Theses and Dissertations

Friction Stir Welding (FSW) was used to perform a Design of Experiment (DOE) to determine the welding parameters effects on yielding consistent mechanical properties across the length of the weld. The travel speed was varied across set forge force and RPM conditions, to find a dataset that will yield consistent mechanical properties independent of the travel speed. Six different welds were completed on two different aluminum panels, the advancing side being Aluminum alloy 2195-T8 at a thickness of .350”, with the retreating side being Aluminum alloy 2219-T851 with a gauge thickness of .360”. A Left-hand Right-hand self-reacting pin tool was …

Studying Chromium And Nickel Equivalency To Identify Viable Additive Manufacturing Stainless Steel Chemistries, Zachary T. Hilton, Joseph William Newkirk, Ronald J. O'Malley

Materials Science and Engineering Faculty Research & Creative Works

Chromium and nickel equivalency modeling has long been used in welding to determine the weldability of steel chemistries. A study was conducted to determine the applicability of Cr-Ni modeling to the additive manufacturing process. Many AM methods involve rapid solidification of small melt pools, similar to welding. Chemistries with varying Cr/Ni ratios were selected for use in a selective laser melting process and modeled using known models. Initial results indicate that the standard "safe welding zone" may not directly apply to additive manufacturing. The capability to build with chemistries outside the weldability “safe zone” could result in improved and varied …

Effect Of Optimizing Particle Size In Laser Metal Deposition With Blown Pre-Mixed Powders, Wei Li, Jingwei Zhang, Xinchang Zhang, Sreekar Karnati, Frank W. Liou

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Functionally Graded Material (FGM) is often fabricated by Laser metal deposition with pre-mixed multiple powders (PMM-powder). Since the supplied PMM-powder directly affects FGM’s composition, investigation on PMM-powder’s property is greatly needed. This paper employed experimental method to observe an important problem: PMM-powder separation in fabricating FGM. A novel particle size optimization method was introduced as solution to eliminate the powder separation. Pre-mixed pure Cu and 4047 Al powders were used to do two experiments. The first experiment result disclosed the existence of powder separation. By optimizing the particle size, the PMM-powder separation was effectively solved in the second experiment result.

Towards Defect Detection In Metal Slm Parts Using Modal Analysis "Fingerprinting", James Urban, Nick E. Capps, Brian M. West, Troy Hartwig, Ben Brown, Robert G. Landers, Douglas A. Bristow, Edward C. Kinzel

Mechanical and Aerospace Engineering Faculty Research & Creative Works

The validation of Additively Manufactured (AM) materials is a difficult and expensive process because the local engineering properties are a function of the thermal history. The thermal history varies with the process parameters, as well as the part geometry. This paper presents a case study using modal testing to identify defects in realistic AM parts. A setup consisting of a Scanning Laser Doppler Vibrometer (LDV) was used to identify the resonant frequencies for several geometrically identical parts on a build plate. Parts with suboptimal process parameters from purposely varying the process parameters, are identified by a shift in the mode …

Construction Of Metallic Glass Structures By Laser-Foil-Printing Technology, Yiyu Shen, Yingqi Li, Hai-Lung Tsai

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Metallic glasses (MGs) have superior mechanical properties such as high tensile strength, hardness, and corrosion resistance, as compared to crystalline metals. Although newly developed MGs have significantly reduced critical cooling rates down to 10 K/s, products of MGs are still limited to simple geometries such as foils/plates or rods with thin section-thickness which is mainly caused by the decrease of thermal conductivities of the new MGs. Recently, we developed a new Laser-foil-printing (LFP) additive manufacturing technology which welds foils, layer by layer, to construct desired 3D structures. With the LFP and Zr-based amorphous foils, 3D, large amorphous structures with complex …

Fabricating Zirconia Parts With Organic Support Material By The Ceramic On-Demand Extrusion Process, Wenbin Li, Amir Ghazanfari, Devin Mcmillen, Andrew Scherff, Ming-Chuan Leu, Greg Hilmas

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Ceramic On-Demand Extrusion (CODE) is an extrusion-based additive manufacturing process recently developed for fabricating dense, functional ceramic components. This paper presents a further development of this process and focuses on fabricating 3 mol% yttria-stabilized zirconia (3YSZ) components that cannot be fabricated without using support structures. The 3YSZ paste is deposited through the main nozzle, and a polycaprolactone (PCL) pellet feedstock is melted and deposited through an auxiliary nozzle to build support structures. After a green part is printed and dried, the support structures are removed by heating the part to ~70 ⁰C to melt the PCL. The part is then …

Development Of A Hybrid Manufacturing Process For Precision Metal Parts, Leon Hill, Todd E. Sparks, Frank W. Liou

Mechanical and Aerospace Engineering Faculty Research & Creative Works

This paper summarizes the research and development of a hybrid manufacturing process to produce fully dense metal parts with CNC-level precision. High performance metals, such as titanium alloys, nickel superalloys, tool steels, stainless steels, etc. can benefit from this process. Coupling the additive and the subtractive processes into a multi-axis workstation, the hybrid process, can produce and repair metal parts with accuracy. The surface quality of the final product is similar to the industrial milling capability. To achieve such a system, issues of the metal deposition process and the automated process planning of the hybrid manufacturing process will be discussed.

Additive Manufacturing Of High Solids Loading Hybrid Rocket Fuel Grains, Stephen P. Johnson, Michael Baier, Ibrahim E. Gunduz, Steven F. Son

The Summer Undergraduate Research Fellowship (SURF) Symposium

Hybrid rocket motors offer many of the benefits of both liquid and solid rocket systems. Like liquid engines, hybrid rocket motors are able to be throttled, can be stopped and restarted, and are safer than solid rocket motors since the fuel and oxidizer are in different physical states. Hybrid rocket motors are similar to solid motors in that they are relatively simple and have a high density-specific impulse. One of the major drawbacks of hybrid rocket motors is a slower burning rate than solid rocket motors. Complex port geometries provide greater burning surface area to compensate for lower burning rates …

Optimization And Control Of Production Of Graphene, Atharva Hans, Nimish M. Awalgaonkar, Majed Alrefae, Ilias Bilionis, Timothy S. Fisher

The Summer Undergraduate Research Fellowship (SURF) Symposium

Graphene is a 2-dimensional element of high practical importance. Despite its exceptional properties, graphene’s real applications in industrial or commercial products have been limited. There are many methods to produce graphene, but none has been successful in commercializing its production. Roll-to-roll plasma chemical vapor deposition (CVD) is used to manufacture graphene at large scale. In this research, we present a Bayesian linear regression model to predict the roll-to-roll plasma system’s electrode voltage and current; given a particular set of inputs. The inputs of the plasma system are power, pressure and concentration of gases; hydrogen, methane, oxygen, nitrogen and argon. This …

Impact Of Diy Home Manufacturing With 3d Printing On The Toy And Game Market, Emily Peterson, Joshua M. Pearce

Department of Materials Science and Engineering Publications

The 2020 toy and game market is projected to be US$135 billion. To determine if 3D printing could affect these markets if consumers offset purchases by 3D printing free designs, this study investigates the 100 most popular downloaded designs at MyMiniFactory in a month. Savings are quantified for using a Lulzbot Mini 3D printer and three filament types: commercial filament, pellet-extruded filament, and post-consumer waste converted to filament with a recyclebot. Case studies probed the quality of: (1) six common complex toys; (2) Lego blocks; and (3) the customizability of open source board games. All filaments analyzed saved the user …

Maximizing Operating Room Performance Using Portfolio Selection, Vivek Reddy Gunna, Amin Abedini, Wei Li

Mechanical Engineering Faculty Publications

The operating room (OR) is responsible for most hospital admissions and is one of the most cost and work intensive areas in the hospital. From recent trends, we observe an ironic parallel increase among expenditure and waiting time. Therefore, improving OR scheduling has become obligatory, particularly in terms of patient flow and benefit. Most of the hospitals rely on average patient arrivals and processing times in OR planning. But in practice, variations in arrivals and processing times causes high instability in OR performance. Our model of optimization provides OR schedules maximizing patient flow and benefit at a fixed level of …

An Optimization Model For Operating Room Scheduling To Reduce Blocking Across The Perioperative Process, Amin Abedini, Wei Li, Honghan Ye

Mechanical Engineering Faculty Publications

Operating room (OR) scheduling is important. Because of increasing demand for surgical services, hospitals must provide high quality care more efficiently with limited resources. When constructing the OR schedule, it is necessary to consider the availability of downstream resources, such as intensive care unit (ICU) and post anaesthesia care unit (PACU). The unavailability of downstream resources causes blockings between every two consecutive stages. In this paper we address the master surgical schedule (MSS) problem in order to minimize blockings between two consecutive stages. First, we present a blocking minimization (BM) model for the MSS by using integer programming, based on …

Three Hundred And Sixty Degree Real-Time Monitoring Of 3-D Printing Using Computer Analysis Of Two Camera Views, Siranee Nuchitprasitchai, Michael C. Roggemann, Joshua M. Pearce

Department of Materials Science and Engineering Publications

Prosumer (producing consumer)-based desktop additive manufacturing has been enabled by the recent radical reduction in 3-D printer capital costs created by the open-source release of the self-replicating rapid prototype (RepRap). To continue this success, there have been some efforts to improve reliability, which are either too expensive or lacked automation. A promising method to improve reliability is to use computer vision, although the success rates are still too low for widespread use. To overcome these challenges an open source low-cost reliable real-time optimal monitoring platform for 3-D printing from double cameras is presented here. This error detection system is implemented …

Free And Open Source 3-D Model Customizer For Websites To Democratize Design With Openscad, Yuenyong Nilsiam, Joshua M. Pearce

Department of Materials Science and Engineering Publications

3-D printing has entered the consumer market because of recent radical price declines. Consumers can save substantial money by offsetting purchases with DIY pre-designed 3-D printed products. However, even more value can be obtained with distributed manufacturing using mass customization. Unfortunately, the average consumer is not technically sophisticated enough to easily design their own products. One solution to this is the use of an overlay on OpenSCAD parametric code, although current solutions force users to relinquish all rights to their own designs. There is thus a substantial need in the open source design community for a libre 3-D model customizer, …

Energy Payback Time Of A Solar Photovoltaic Powered Waste Plastic Recyclebot System, Shan Zhong, Pratiksha Rakhe, Joshua M. Pearce

Department of Materials Science and Engineering Publications

The growth of both plastic consumption and prosumer 3-D printing are driving an interest in producing 3-D printer filaments from waste plastic. This study quantifies the embodied energy of a vertical DC solar photovoltaic (PV) powered recyclebot based on life cycle energy analysis and compares it to horizontal AC recyclebots, conventional recycling, and the production of a virgin 3-D printer filament. The energy payback time (EPBT) is calculated using the embodied energy of the materials making up the recyclebot itself and is found to be about five days for the extrusion of a poly lactic acid (PLA) filament or 2.5 …

Open Source Multi-Head 3d Printer For Polymer-Metal Composite Component Manufacturing, J. Laureto, Joshua M. Pearce

Department of Materials Science and Engineering Publications

As low-cost desktop 3D printing is now dominated by free and open source self-replicating rapid prototype (RepRap) derivatives, there is an intense interest in extending the scope of potential applications to manufacturing. This study describes a manufacturing technology that enables a constrained set of polymer-metal composite components. This paper provides (1) free and open source hardware and (2) software for printing systems that achieves metal wire embedment into a polymer matrix 3D-printed part via a novel weaving and wrapping method using (3) OpenSCAD and parametric coding for customized g-code commands. Composite parts are evaluated from the technical viability of manufacturing …

Multi-Criteria Flow-Shop Scheduling Optimization, Raviteja Arikati

Industrial and Manufacturing Engineering

A flow-shop is a type of manufacturing job shop where similar jobs follow a similar, linear sequence through the shop. Every day, flow-shops receive several different orders and it is up to the scheduler to plan the daily schedule. This schedule should be designed to prevent bottlenecks in the shop, to have on-time delivery of products, and satisfy several other requirements. Often, schedulers perform subjective scheduling and utilize simple heuristics or just intuition to schedule the jobs. With computer-based scheduling, schedulers can now create schedules and determine quantitatively what sorts of schedules work best. Currently, much of the computer-based schedules …

Yeager Multi-Function Tool Ql+, Osiel Flores-Hernandez, Carter Wilson, David Wright, Mitchell Jackson

Industrial and Manufacturing Engineering

No abstract provided.

Polar Coordinate Farm Bot Final Project Report, John Brown, Kasenia Colombo, Lucas Salem, Ning Jeng, Rory Stothers, Sam Lees

Industrial and Manufacturing Engineering

FarmBot Inc. is a local startup that is advancing precision agriculture through automation and open source technology. The original FarmBot model, FarmBot Genesis, operates over a rectangular area of 3 x 1.5 meters. It plants, waters, weeds and grows produce autonomously using CNC technology. Our project sponsor and inventor of FarmBot, Rory Aronson, tasked our team with developing and testing a polar coordinate farmbot capable of performing on par with the Cartesian farmbot in growing a circular vegetable garden in a user’s backyard. A successful project was defined by meeting specific customer requirements and engineering specifications predetermined and discussed with …

Design Of An Automated Welding Process For Synergy Mfg., Parsa Bakhtiari

Industrial and Manufacturing Engineering

This senior project involves a partnership with a local off-road parts manufacturer called Synergy Mfg. Synergy is experiencing a rapid increase in demand that is difficult to meet with their current processes. Because of this issue, Synergy is exploring automation in order to decrease their cycle times and increase their production output. More specifically, this report concentrates on automating a manual welding process that has a lengthy cycle time which causes Synergy’s difficulties with meeting demand. Due to time constraints, this project focused on the automation of a welding process for only one part that Synergy produces. This part contains …

Predictive Analytics In Forecasting, Matthew Suarez

Industrial and Manufacturing Engineering

Predicting future demand can be of tremendous help to businesses in scheduling and allocating appropriate amounts of material and labor. The more accurate these predictions are, the more the business will save money by matching supply with demand as closely as possible. The approach for an accurate forecast, and the goal of this project, involves using data analytics techniques on past historical sales data. Working with Campus Dining, a year's worth of their daily sales data will be analyzed and ultimately used for the end result of both an accurate forecasting technique and a way to display the results in …

Design Of A Finger Lime Loading System, Joel Jameson Hitchen

Industrial and Manufacturing Engineering

Automation for post harvest processing of finger limes is required to meet demand for the new citrus fruit being introduced to United States of America food and agriculture market. As labor wages rise, and demand climbs for finger lime product a creative solution is needed to eliminate human labor and reduce the manual input needed to process finger limes. Building on an already successful processing tool, a semi-­automated loading system was designed and implemented to overcome the problem.

Effect Of Composition And Build Direction On Additively Manufactured Hastelloy X Alloys, Justin A. Spitzer, Jeffrey T. Schloetter, Sarah Zerga

Materials Engineering

Microcracking has caused premature failure and reduction in properties in additively manufactured (AM) Hastelloy X. The purpose of this research is to meet or exceed the mechanical properties of wrought Hastelloy X by modifying the composition and build direction of Hastelloy X manufactured using Direct Metal Deposition (DMD). Tensile testing, scanning electron microscopy (SEM), and metallography were performed on the samples. ANOVA was used to analyze the dependence that the properties had on build direction and composition. The nominal composition wrought samples had a yield strength of 310.1 MPa and a 60.79% Elongation. Alloy P60-X18 in a horizontal build had …

Additive Manufacturing For Post-Processing, Nathan D. Goodwin, Andrew Furmidge

Mechanical Engineering

Additive Manufacturing for Post Processing (AMPP) is a team comprised of two Cal Poly Mechanical Engineering students: Nathan Goodwin and Andrew Furmidge. The project is focused in the area of metal additive manufacturing (AM) machines, which are still a developing technology. Improvements have been made to the quality of the machines in the past years, but many limitations still exist. One of these is the inability to print parts that are larger than the build volume. In an effort to solve this problem, whole parts are divided into pieces that are printed individually. This team’s senior project is to create …

Bear Minimum: Ultralight Composite Bear Canister, Rama B. Adajian, Adam C. Eisenbarth

Mechanical Engineering

The ultralight backpacking community needs a strong, easy to use, safe bear canister that is lighter than current market products for trekking in the backcountry. A full design of the lid for the bear canister is to be completed. This includes the locking mechanism to ensure it is bear proof, the interface between the lid and the canister, and the structure of the lid so it passes the strength and weight specifications. The lid, along with the already designed canister body, is to be manufactured with formal documentation. The lid will initially be tested separately and then with the canister …

Characterization Of Flexible Hybrid Electronics Using Stretchable Silver Ink And Ultra-Thin Silicon Die, Joshua A. Ledgerwood

Master's Theses

Flexible Hybrid Electronics (FHEs) offer many advantages to the future of wearable technology. By combining the dynamic performance of conductive inks, and the functionality of ultra-thinned, traditional IC technology, new FHE devices allow for development of applications previously excluded by relying on a specific type of electronics technology.

The characterization and reliability analysis of stretchable conductive inks paired with ultra-thin silicon die in theµm range was conducted. A silver based ink designed to be stretchable was screen printed on a TPU substrate and cured using box oven, conveyor convection oven, and photonic curing processes. Reliability tests were conducted including a …

Inyo National Forest Sign Maker, Brandon Mainini, Lauren Kirk, Alec Boyer

Mechanical Engineering

No abstract provided.

Development Of 3d Compression Molded Composite Primary Structure, Sean D. Tischler, Jacob H. Goldstein, Alea A. Perez

Mechanical Engineering

The work accomplished by the Black Gold team improved upon the carbon fiber compression molding research and information available on the Cal Poly San Luis Obispo campus. The team used the rear suspension rocker arm off a Ventana Alpino mountain bike as a design goal for this project. This research and body of work includes the methods used to design a compression molded part for complex part loading and shape. This extends to the process of choosing an appropriate layup process, in addition to benefits and drawbacks of the use of chopped fibers in compression molding. The research includes the …

Leading Edge Boundary Layer Suction Device For The Cal Poly Rolling Road Wind Tunnel, Daniel C. Glover, Liam M. Madden, Robert J. Cabri

Mechanical Engineering

Over the course of three quarters from Fall of 2016 to Spring of 2017, our team designed and built a boundary layer suction device. The boundary layer suction device has three main functions: a scoop that redirects most of the boundary layer air out of the wind tunnel, fans that suck the remaining boundary layer air through a porous plate and ducting and out of the wind tunnel, and a transition bridge that transitions the remaining air smoothly onto the rolling road. The wind tunnel is owned by Cal Poly and the rolling road is a new addition to it. …

Universal Fixture For Orbital Tube Welding, Kevin P. Mcgowan, William Divittorio, Jesse Castaneda

Mechanical Engineering

No abstract provided.