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ZACH CARRIZALES

Portfolio

Exzactlines, LLC Engineering & Design Littleton, CO 80127 United States

Contact Information: Cell: (303) 842-9787 Email: exzactlines@gmail.com www.exzactlines.com

A Brief Introduction |

My name is Zach Carrizales, I am an ambitious 24-year-old, mechanical engineering graduate that lives to design, strives to build, insight wonder and allure in everyday life and the people around me. I utilize my high-energy, passion and a “win-win” frame of mind to create opportunities. My ability to see the bigger picture and my unique creative adeptness for problem solving strategies, in conjunction with my insatiable curiosity for all things engineering drives my commitment to create amazing things.

My Work |

My work is a culmination of all of the subjects and topics that my mind tends to wander toward. Many of my projects were possible because of my opportunities in college at Colorado State University. These projects took many forms, but can easily be summed with a few simple words; I like to make cool shit. The ‘Ooo’s’ and ‘Aaah’s’ from a marvelous and awesome experience can ignite a brief moment of pure wonder and elation in a true form. This is the source where I draw my passion for why I do what I do; the wonder in a moment.

1. Damage Tolerance Capability of Composite Joints 2. Multi-material 3D Printed Compliant Prosthetic Finger Project 3. The Archetype – A Custom 3D Printer 4. 3D Printed Thermoplastic Urethane Heart Valve Research Project 5. 3D Printed Biomechanically-sound Finger Demonstration Model 6. 3D Scanned and 3D Printed ABS Elephant Sculpture for the Loveland, Colorado International

Snow Sculpture Team 7. Manual Belt-Driven Record Player – Mechatronics Project 8. PTC Creo Café Racer

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Damage Tolerance Capability of Composite Joints

– A Boeing Sponsored Senior Design Project

Problem Statement Investigate composite joint design alternatives that could lead to improved performance with enhanced damage tolerance capability while creating a method or tool capable of optimizing joint performance. Overview The challenge of truly understanding and performing a true damage tolerance analysis of adhesively bonded composite material joints proved to be much more daunting than initial expectations. The challenges of modeling composite materials are the disparities between numerical modeling and observed material behavior in reality. Many of the current challenges are the high computational costs and that fact that validation requires trial and error testing for optimization. For the aviation industry, a predominant industry where composite materials are used, the major concern for the damage tolerance capability of composite materials is the loading of matrix material. When the matrix material is loaded (in most cases a two-part resin), safety issues during flight and increased costs due to higher inspection frequency, in addition to increased risk of failure.

Software Solidworks ANSYS Workbench ABAQUS CAE The project required my team and I to develop a tool to improve damage tolerance of composite joints. The team chose to use a three-step approach that utilized numerical modeling, mechanical testing, and then assessing predictability. The project focused on unidirectional carbon fiber prepreg composite material and three common forms of adhesively bonded lap joints; single-lap joints, double-lap joints

Challenges The most challenging component of the project proved to be the disparity between numerical modeling software capability and what would have been required to produce more accurate results. This required us to constantly find solutions to overcome these issues and improve our models predictive capability. The major plan deviation we had to perform was refining the scope from multiple complex geometries, that was originally planned, to single and double lap joints only. The reason for this adjustment were the due to limitations in modeling change in fiber direction with geometry. We switched from using ANSYS to ABAQUS because ANSYS was limited to zero thickness cohesive elements in ANSYS. Lastly, we had difficulty obtaining ABAQUS CAE research license because of the late plan deviation as it was outside of the project budget.

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Analysis 1. Data suggests closed-form adherend strength differs greatly from test

a. Peel stress likely contributed to low failure loads 2. Adhesive interface failures from low surface roughness 3. Double lap cohesive failure lower than predicted 4. Likely due to stress concentrations in adhesive build-up

Results Although the project was filled with a multitude of deviations we made four major conclusions from our study. Improvement conclusions

1. Manage adhesive build-up from flow a. Create fixture to control flow direction b. Control adhesive shape c. Machine excess adhesive overflow d. Move to film adhesive

Conclusions Although the project was filled with a multitude of deviations we made four major conclusions from our study and we ultimately could not complete what our team was initially tasked to do, we did collect the data to make several major conclusions. The four major conclusions that were uncovered throughout this project were:

1. Adhesive requires additional testing to isolate normal and shear delamination a. Double cantilever beam tests and End-notched flexural tests

2. Surface preparation is critical to achieve best adhesive performance 3. Helius PFA can output accurate predictions in the case of laminates 4. Helius PFA susceptible to inconsistencies produced from defects.

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Multi-material 3D Printed Compliant Prosthetic Finger Project – An Independent Study Project Problem Statement Investigate the additive manufacturing capabilities of ABS and TPU thermoplastic polymer filaments with current desktop 3D printing devices and the application of these materials in low-cost, compliant prosthetics. Overview In this study, I tested dual-material interaction capabilities of ABS and TPU thermoplastic polymer filaments and their application in a no-assembly, compliant prosthetic finger. Suitable designs for compliant mechanisms with no-assembly capabilities that simulate grasping were considered and selected. Models that demonstrated the most potential closely simulated a tenodesis grasp and release, an orthopedic observation of a passive hand grasp and release mechanism, effected by wrist extension or flexion, respectively. The tenodesis grasp was emulated because a model could be 3D printed in the inactivated state and return to that state under the compliant material’s elastic properties. Prototypical finger models were 3D printed in a single process in ABS and TPU using a dual-material melt extrusion printer, with no assembly of components. Software Used:

Solidworks 2015-16 Student Edition

ANSYS 2015-16

Simplify 3D Slicing Software

Lulzbot Cura Slicing Engine

Results The capability for dual-material 3D printing of compliant prosthetic devices using commercially available materials and devices is there, however developments need to be made in how low viscosity materials, like TPU, are printed. Additionally, further research and topology optimization could be performed to design a better device that displays more finger extension and grip force with less activation energy – or better control of material print density to channel input force more efficiently.

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The Archetype – A Custom 3D Printer Problem Statement Current 3D printers grow increasing costly as bed volumes increase, however accuracy and overall functionality do not increase by the same margin as you spend more money. I discovered that I could build a device with a larger build volume, improved mechanical precise functionality and a climate controlled, enclosed build volume for a fraction of the cost of what I could buy it for. Overview I am currently designing and building a custom 3D printer that represents the culmination of the many lessons I learned while working with extrusion-based 3D printing systems at the Idea2Product 3D Printing and Scanning Lab at Colorado State University. Specifically, the areas I am focused on improving are;

1. Minimizing part count without decreased print function or proficiency. a. Linear Ball Screw – using linear ball screws instead of lead screws as an actuation

source allows for minimized backlash and extends actuation system lifetime. b. Sarrus Linkage Print Bed design – which provides one actuation source – limiting

chance of binding, linkage design that minimizes need for constant manual bed leveling.

2. 400mm x 320mm Print platform a. Increases print volume to use for larger flat parts

3. Temperature Controlled Enclosed Build Volume a. More heat efficient material printing temperature conditions b. More consistent part heating and cooling during printing

Below are some early design pictures displaying prominent 3D printer components.

Current Status The Archetype 3D Printer is currently still being built and is awaiting delivery of final components before assembly.

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3D Printed Thermoplastic Urethane Heart Valve – A Research Project Problem Statement Explore the capability, potential and limitations of using current additive manufacturing technology to produce synthetic heart valves out of thermoplastic urethane. Overview Traditionally heart valve leaflets are made in several ways, either through hand-stitching animal heart valve leaflets to frames and then surgically implanting them into the patient. These traditional, porcine (pig) valves often require replacement after a designated number of fatigue cycles – between 10-15 years. The 3D printed Thermoplastic Polyurethane Heart Valve project aimed to improve the ease of producing artificial heart valves, improve the potential geometries that are possible to produce and improve fatigue life of the valve leaflets themselves. I took over the production or 3D printing of the TPU sample sheets for the director of the project, Dr. David Prawel, and learned a great deal. The most notable things I learned about were the capability of the extrusion-based 3D printers on the market, the incredible material properties of Thermoplastic Polyurethane plastic, and how 3D printing (along with other additive manufacturing technology) may revolutionize personal health care. Results The results of testing the test samples that were cut out of the sheets I printed showed remarkable fatigue capability, coupled with the good bio-compatibility gave Dr. David Prawel the confidence to file a provisional patent naming me and several other project researchers as inventors on the patent.

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3D Printed Biomechanically-sound Finger Demonstration Model – An Academic Teaching Aid Problem Statement There are very few biomechanically correct demonstration models to illustrate the movement and functionality of the human finger. Overview The lack of functional bio-mechanically correct movement in anatomy teaching demonstration devices prompted this collaboration between Dr. David Greene and me. The motion of bio-mechanical movement was decided based on the instruction of Dr. David Greene and his years of experience in the occupational therapy field, while I designed the model shown below. Dr. David Greene is now using several these models for a class he teaches to demonstrate the motion of the human finger including the major tendons and the general motion of the finger. Shown on the right is a picture of the first prototype of the concept that was created by Professor Dr. David Greene to demonstrate the simple biomechanical function of the finger. In this original prototype Dr. Greene used wooden blocks as the metacarpal and the phalanges, while strings (shown in white and yellow) were used to demonstrate the tendon/muscle motion. The metacarpal bones was fixed to the base plate using finishing nails and eye hooks were used to route the strings in accordance with the typical path of the tendons in the finger. Results Dr. Greene’s prototype was used as inspiration for a more robust design and anatomically correct size which I modeled and printed. Below, shows early ideas and proof of concept (left) and a print of the final design (right) before final assembly.

Dr. Greene is now working on the second itteration of this finger demonstration model for even more biomedchanically sound finger functionality.

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3D Scanned and 3D Printed ABS Elephant Sculpture for the Loveland, Colorado International Snow Sculpture Team – A Commercial Project Problem Statement Could we scan a clay sculpture with fine details and reproduce it digitally then 3D print a replica in ABS using a TAZ 5 3D printer. Overview Loveland, Colorado International Snow Sculpture team needs a more robust reference model, besides an unfired clay model, to use during their competition in Breckenridge, Colorado. The team came to our lab to have the clay model 3D scanned and then that digital model printed out of plastic to be used as the durable model during the competition as reference. I and one other I2P lab employee worked on the project together, splitting the digital processing, printing and final assembly equally. The scanning process turned out to be extremely challenging, taking nearly 4 scan attempts, nearly 8 hours of scanning and digital mesh manipulation using MeshMixer, Blender and Netfabb software to prepare the model so that it could be printed. Because the digital model needed to be a 1:1 scale of clay model we could not print the model in one whole piece and had to be cut digitally. Each portion was printed, 3 hours of post processing was performed to removed support material, after printing and then the printed model was assembled using a two part epoxy.

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The final 3D printed model was a near prefect duplicate of the clay model, 3D printed in ABS, delivered on time to be used by the team during the International Snow Sculpture contest.

The final snow sculpture is shown below in Breckenridge, a few days after the event was open to the public. The Snow Sculpture team from Loveland the I2P helped out, ended up placing 3rd in the event. Warm weather during the days following the event caused a few of the other teams sculptures to crumble, the elephant sculpture was lucky enough to endure the warm weather only sustaining minor damage to the right tusk.

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The Manual Belt-Driven Record Player – A Mechatronics Project Problem Statement Conceptualize, design, fabricate, revise and present a mechatronic device that displays mechanical ingenuity and electronic component understanding of class concepts. Overview Tasked with performing the initial phases of early product development for a class, I and 4 other team members decided to create a manual record player with 4 key end goals.

1. Produce a device that met all the mechanical and electronic component requirements. 2. Meet the early deadline goals. 3. Produce a record player that produced a quality sound. 4. Produce a finish product that displayed the product refinement of a marketable product.

Results Final assembly and testing was performed ironing out some of the minor kinks. Overall, the record player was designed and built with some neat functionality including a speed adjustment setting to play both 33 and 45 records. Additionally, the lights and volume nob located in the front of the machine would light up and pulsate outward during the startup sequence, then returning to the previous volume setting. We could not, however solve an amplification issue we ran into. The simple pre-amp that we thought would be enough to amplify the sound before entering the speakers was not quite enough. Granted we could hear quality music coming from the record player, we could not increase the volume passed a certain point. Ultimately, the team met all four of the key goals we set out to meet in addition to scoring well on the final grade.

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PTC Creo Café Racer – A CAD Project Problem Statement Design and render an assembly of at least 12 individual parts using PTC Creo Parametric to demonstrate proficiency in the software. Overview Using PTC Creo Parametric CAD software I partnered with one other mechanical engineer to devise a beautiful cafe racer that blended classic cafe racer design characteristics with imaginative new design approaches. We were tasked with merely demonstrating our skills with the Creo software and utilizing the techniques taught in the curriculum to produce an object and rendering that culminated in more than twelve parts. The design we came up with does not possess real world dimensioning or tolerances, and therefore could not be built. However, I think my teammate and I were, ultimately, successful in producing a beautiful rendering.

Results The work on the rendered images and CAD files for this particular project earned my partner and I a perfect score plus additional points for going beyond the project’s requirements and producing a stunning result.