Paper ID #33423
Integrating 3D Printing into Engineering Technology Curriculum
Dr. Mert Bal, Miami University
Mert Bal received his PhD degree in Mechanical Engineering from the Eastern Mediterranean Univer- sity, North Cyprus in 2008. He was a Post-Doctoral Fellow in the University of Western Ontario, and a Visiting Researcher at the National Research Council Canada in London, Ontario, Canada between 2008 and 2010. He was involved in various research projects in the areas of collaborative intelligence, localiza- tion and collaborative information processing in wireless sensor networks, intelligent agents, agent-based manufacturing scheduling, systems control and automation, distributed control of holonic systems and integrated manufacturing, agile manufacturing, virtual reality and remote laboratory applications in edu- cation. He has authored or co-authored various journal and conference publications in these areas. Mert Bal is currently the Chair and Associate Professor at the Miami University, Department of Engineering Technology, Ohio, United States of America.
Dr. Farnaz Pakdel, Miami University
American Society for Engineering Education, 2021c
Integrating 3D Printing into Engineering Technology Curriculum 1. Introduction
Three-dimensional (3-D) printing has witnessed significant improvements since its inception as this process enables economical and rapid prototyping of various product designs within a very short time period. The recent technical advancement in 3-D printing managed to scale down the size of 3-D printers and the complexity of process, where it is a more affordable technology for educators, students, engineers, researchers and scientists [1].
Through 3-D printing technology, complex geometric shapes, multi-material and
multi-functional parts can be additively manufactured in a single operation which is a big advantage over conventional manufacturing processes. Large portion of the manufacturing industry has realized the benefits of the AM technology and started utilizing AM as an integral part of their processes. For example, General Electric (GE) Corporation has invested
approximately $1.5 billion in advanced manufacturing and additive technologies, in addition to building a global network of Additive centers focused on advancing science [2]. The company uses the additive manufacturing processes for manufacturing its jet engine nozzles because it uses less material than conventional techniques. That reduces production costs and, because it makes the parts lighter, yields significant fuel savings for airlines. Conventional techniques would require welding about 20 small pieces together, a labor-intensive process in which a high percentage of the material ends up being scrapped [3]. In order to be competent, modern
engineers will need more advanced skills in CAD and optimization that focus on construction of 3-D structures with a growing number of metals, plastic, ceramic and gel materials [4].
Increasing use of 3-D printing technologies in industrial applications such as design and prototyping of products, has started creating demands for a skilled workforce of engineers and technicians who are proficient in all aspects of the additive manufacturing processes, from software-driven 3-D designs to hands-on execution of these designs using modern 3-D printing platforms. These recent developments in the 3-D printing sector has also taken the attention of many higher education institutions to assure that their students get familiar with the 3-D printing technologies and get well-prepared to industry. For maximum effectiveness, this integration often requires development of higher education institutions offering educational programs or
coursework. A growing number of institutions have started investing on 3-D printers of various kinds and integrate them into their engineering or technology education curriculum throughout systematic coursework that focuses on the main principles of the technology, so that their students can receive instruction and experience on the design principles for 3-D printing, proper selection of printing materials as well as proper operation techniques of the 3-D printing
machines and corresponding modeling and slicing software tools [5].
This paper presents one such effort of integrating 3-D printing technology into engineering technology curriculum by means of a hands-on elective course on 3-D printing. The course focuses on various aspects of 3-D printing technologies and it aims to teach the engineering and technology students proper design and operation techniques of various 3-D printing techniques including the choices of 3-D printing platforms as well as different modeling and slicing techniques. In this paper, we discuss the hands-on experiments and projects of the 3-D printing course and describe the teaching experiences in this course gathered over the past three years at the Department of Engineering Technology at the Miami University.
2. Elective Course: Introduction to 3-D Printing
Introduction to 3-D Printing is a 12-week long elective course designed for provide instruction and hands-on experiences to engineering, engineering technology as well as non-engineering or technology major students using a variety of laboratory experiments on key topics of additive manufacturing. The course consists of both lecture and laboratory sessions. However, most contents of this course have been developed as lab-intensive with the aim of providing the students with maximal learning experience on the technology via the experiential learning approach. The laboratory activities designed for this course allow students to discover for themselves the potential and limitations of 3-D Printing through a build design project.
This course is intended for registered Miami University students with minimal prior exposure to Computer Aided Drafting (CAD) or manufacturing technologies. It will be particularly useful to students outside of engineering and design who find themselves on a multi-disciplinary product design team, such as those in the business school or medical schools. Students will learn the history, current applications, materials, methods of 3-D printing which are currently in use in the industry. They will also gain hands-on experience on using 3D modeling software and operating various 3-D printers to create and print their designs.
For the delivery of the laboratory activities of the course, the computer workstations and 3-D printing equipment available in the Additive Manufacturing Laboratory (AM Lab) of the Miami University is utilized. The AM Lab at Miami University is partially funded by state equipment grants and it includes several 3-D modeling and printing equipment of various types.
The AM Lab consists of a mix of CubePro™ and Makerbot™ FDA printers with capabilities of printing various types of polymeric materials (PVS, ABS, Nylon etc.). The lab also includes one MCOR™ IRIS paper-based printer, a ProJet™ 260c sandstone printer and a Nobel 1.0™ UV Laser SLA printer. The lab also involves two high-end, high-definition 3-D scanners from
NextEngine™, and Artec™. The course covers techniques for basic 3-D modeling techniques to create solid models with appropriate design intent. The lab uses AutoCAD™ and as the main modeling platform. In order to improve design skills with complex geometries, students are given lab activities which require them to design by looking at the aspect of 3-D printing. After having given basic dimensional and functional requirements, the students are asked to model their products with complex features and use the advantages of 3-D printing for generating a physical prototype of it. Students are left free to work on their project during the class periods and their efforts are systematically observed during the class presentations. The typical weekly schedule of the course is presented in Table 1.
The student learning outcomes of the Introduction to 3D Printing course are as follows: Upon completion of the course,
i. Students will be able to think critically about public reports of 3-D printing in the media;
ii. Students will be able to identify 3-D printing techniques and describe the differences between the 3-D printing and the traditional methods of manufacturing;
iii. Students will be able to access specific resources needed to 3-D print an object; include CAD software, CAD libraries, additional CAD and printing web tutorials, and 3-D printing service providers;
iv. Students will be able to be able to open, view, manipulate and edit three-dimensional object files;
v. Students will be able to create new three-dimensional object files from scratch;
vi. Students will be able to Prepare and optimize those files for 3D printing;
vii. Students will be able to perform all steps necessary to 3-D print a simple, custom object using Fused Deposition Modeling (FDM) and Laminated Object Modeling (LOM)-based printers.
Table 1: Weekly schedule of the Lecture Topics and Lab Activities
Week(s) Lecture Topic and Lab Activity
1
Lecture: Course Introductions. Definition and history of additive manufacturing. Comparison of additive manufacturing with traditional manufacturing.
Exploring the types of 3D printing. Basic forms of Additive Manufacturing. Advantages and limitations of 3D printing processes.
Lab Orientation: Lab Safety, Tour of Additive Manufacturing Lab. Introducing the 3D printing equipment. 3D printing demonstration.
2-3
Lecture: How does 3D printing work? Classification of additive manufacturing processes and materials. Polymer and paper-based printing processes. Metal and ceramic powder processes. Quality issues and analysis.
Lab Activity 1: Identifying sources for 3D-Printable Objects. Object repositories. Introduction to Grab CAD and Thing verse.
Setup and model preparation for MakerBot and CubePro FDM printers. Download and print with an FDM machine.
4-5
Lecture: Business aspects of 3D Printing. Global impacts of 3D printing on business and manufacturing. Ethics of additive manufacturing. Future of 3D-printed designs.
Lab Activity 2: Setup and model preparation using 3D scanners. Scan and print with desktop and handheld 3D scanners.
5-6
Lecture: Introduction to computer aided design (CAD) using 3D modeling. Model generation and editing for 3D printing using CAD software. Mesh editing and slicing applications. Lab Activity 3: Setup and model preparation for Nobel 1.0 SLA and ProJet Binder-Jetting 3D Printer. Design a 3D object, modify and print using Tinker CAD.
7-8
Lecture: Introduction to 3D solid model generation. Geometric analysis for manufacturability with 3D printers.
Lab Activity 4: Setup and model preparation for MCOR-IRIS Paper-based 3D printer. Download, modify and print using AutoCAD 3-D.
9-12 Lab activity 5: Final Project. Work on the final project. Generate, prepare and 3D print a complex, functional model.
3. 3-D Printing Laboratory Activities
a. Lab Activity: Download and Print a 3D Design with FDM
In this lab activity, the students explore available repositories for 3-D printing objects and download 3-D design files from the web. The goal of this activity is to familiarize the students with the steps of the rapid prototyping process as well as the slicing software or other similar apps needed for operating the 3-D printers. In this activity, each student is assigned with a task to search online repository websites such as Thing verse, Grab CAD and others to find and
download an already existing 3-D model file in STL file format. Then the students are required to follow the given instructions and 3-D print the selected file by using a Fused Deposition Modeling (FDM) printer.
In order to operate the FDA printer, students are also given instructions to set up and configure the slicing software used for the 3-D printer they would like to use. If they would like to use the MakerBot printer, then they are required to use the MakerBot Print app to prepare their models for printing. The students learn the basic steps of preparing the STL files for 3-D printing. They first insert the STL file into the 3-D print platform and adjust its position and orientation along with the printer settings. To optimize the print time, the students are advised to scale the STL model down so the resulting printed object dimensions would fit in a cube of maximum 2 or 3 cubic inches.
Figure 1: Scaling STL object in MakerBot app.
b. Lab Activity: Design and Print a CAD Object (Eye Bracket)
In this lab activity, the students are assigned a task of creating and 3-D printing a
miniature-sized, custom eye bracket and a mating pin part using a web-based CAD environment. An eye bracket is a very common engineering part that is used to make parts in a simple and convenient way using standard fasteners, and it allows for easy future disassembly if needed. The
design of an eye bracket has been chosen for this assignment since it has a modeling complexity that is appropriate to the expected competency level of the students. Two-piece composition is also another useful feature of the eye bracket design that makes it suitable for this application. Building a part that is composed of two mating pieces helps students realize the capabilities and limitations of some 3-D printing techniques in achieving close tolerances.
For the CAD modeling part of the assignment, the students use the Tinker CAD, browser-based CAD modeling platform. TinkerCAD is an online modeling application from Autodesk,
commonly used for modeling for 3D printing applications. TinkerCAD is chosen for this lab activity due to its ease of access and easy learning curve. Students are provided with basic instructions on 3-D CAD modelling with TinkerCAD. They are also provided a step-by-step tutorial on modeling simple objects prior to doing the assigned lab activity.
Once they complete the tutorial, the students are required to design a 3-D model of an eye bracket shown in Figure 2, and a simple Shackle with a pin that would assemble with the clearance fit in the eye bracket (See Figure 3). Students must decide the dimensions of the shackle based on the existing eye bracket dimensions. Students are reminded to incorporate additional clearance in the dimensions of the CAD model when they are to 3-D print parts that have to fit/slide together after printing. Students usually better determine the amount of required clearance by experimentation. In our experience, if an FDM printer is to be used, a good starting place for clearance is two times the layer height at which the printing is going to take place. Students are given this tip and they are asked to make a few smaller test prints at different clearances to find out if the 2x layer height rule holds for their situation and model orientation.
Figure 2: Orthographic and Isometric Views of the Eye Bracket as provided to the students in the lab handout.
Figure 3: Sample eye bracket and shackle design picture as provided to the students in the lab handout.
c. Lab Activity: Scan, Modify and Print – PHASE 1
This lab activity focuses on 3-D modeling via 3-D scanning technologies, in which students are asked to generate and print a miniature-sized, custom part by generating a CAD model by 3-D scanning an existing object. This project is the first one of the two lab activities designed with the scope of familiarizing the students with alternate methods of generating 3-D model files using 3-D scanners. The activity also aims at improving students’ understanding and skills on post processing the model files by editing or modifying them before physical prototyping. The PHASE 1 of this lab activity uses Nextengine Desktop 3D Laser Scanner for generating a CAD model from an existing object. The PHASE 2 uses a handheld, high resolution 3-D scanner, which is explained in the next section.
Once the students scan their model objects with the Desktop scanner, they are asked to post-process their models and correct the defects on the model which are resulting from laser scanning. For this purpose, the students need to modify the result of the scan using the Next Engine scanner app. Students are given instructions and a step-by-step tutorial to use this
software. Once they completed the post processing, the students transfer the completed model to printer slicer software, modify and prepare for printing and print the scanned model with an FDM printer. The use of 3-D scanner software application for scanning and model preparation involves several steps that require students to manually adjust and calibrate the several images of the scanned object model. Students spend a considerable amount of time learning the tips and tricks of the calibration process in order to be able to complete their scans.
d. Lab Activity: Scan, Modify and Print – PHASE 2
In the PHASE 2 of this lab activity, the students create and print a miniature-sized, custom part by generating a CAD model through scanning an actual object using an Artec Spider Handheld Scanner (Figure 4). Once the model is generated with the Artec Spider, the students will need to modify the result of the scan using a free 3D modeling app called the 3D Builder. You will print
the final model with a MakerBot 3D Printer. By scanning the model with the Artec Spider scanner, students generate a base model file. They are then asked to import the file into a 3D Builder app for additional modifications. We typically ask students to add an additional feature to the scanned model in the 3D builder app such as a flat stand or foundation that would attach at the bottom of the model, or a handle or a ring to attach keys or other parts to it.
Students are given step-by-step instructions and a demonstration of using the Artec Spider software called the “Artec Studio 12 Professional”. Like the 3D scanner app in the Phase 1 of this lab activity, the Artec Studio app also requires calibration and processing for correcting the scanned models. Figure 5 shows snapshots taken from this app during the modeling and processing of the 3-D scan.
Once the customizations are added to the model, students are asked to scale their models down to a size suitable to be 3-D printed within a couple of hours. Typically, we will scale the object for it to be able to fit in a cube of 2x2x2 in dimensions in order to optimize the total prototyping time.
Figure 4: Artec Spider Handheld 3-D Scanner
Figure 5: Calibration and 3-D Scanning of models with Artec Studio Professional
e. Lab Activity: Design and Print 3D Objects with AutoCAD and MCOR IRIS Printer In this lab activity, students create 3-D object models using AutoCAD professional CAD
modeling software, which is commonly used in many areas of engineering. Students also use the MCOR IRIS Paper-based 3D printer to produce their designs.
Students are first provided with a step-by-step tutorial on basics of 3D modeling with AutoCAD. Once a basic example on 3-D solid modeling is completed, the students are then moved to modeling a small 3-D wrench model with given dimensions using AutoCAD (See Figure 6). At this point, we also provide the students the basic tip of drawing the wrench on a separate handout. They are first asked to draw the given geometry of the wrench in 2-D. Then, they are
asked to extrude the model into a 3-D solid model. The final step of modeling is filleting the edges of the wrench.
Figure 6: 2-D and 3-D models of the wrench used in the lab activity
Once the model is completed, the students are then asked to post process the wrench model file for printing with the MCOR IRIS paper-based printer. MCOR IRIS is a high-end printer that uses recycled paper as the print material (Figure 7). It produces durable parts by adhering layers of recycled paper via a high-strength adhesive. The 3-D printing technology MCOR IRIS uses is a variant of the Laminated Object Modeling (LOM) technique.
Figure 7: MCOR-IRIS Paper Printer (left) - students scanning an object with the Artec Spider Handheld scanner (right)
f. Lab Activity: Design and Print a Geneva Drive Display Stand (Team Project) In this final lab activity, the students are asked to work in teams of two or three students to design a functional Geneva Drive system mounted on a base and vertical stand. To begin the project, students are first presented with videos and animated pictures showing the operating principle and the principle of Geneva Drive mechanism. We also instruct students the basic proportions required for building a functioning Geneva gear pair. Then the students are asked to design the system by determining suitable form and dimensions for construction of the 3-D models.
This activity requires students to use complete CAD software such as AutoCAD for building the 3-D models. They can choose any of the 3-D technologies available to use for printing their models.
The figure 8 below shows an example of a basic Geneva mechanism and its components.
In this team project, we work closely with the students and supervise them to make sure that they generate a functioning product model and a physical prototype. We discuss with the students the other desired features and requirements as needed. Students are expected to create the CAD models of the separate parts of the stand individually as the design and assembly must be carried out in teams. Multiple parts may be printed separately and assembled to achieve a functioning product. So, they must consider splitting the CAD modeling tasks once the design is made. Students must also consider adding their names/initials and date of completion into their models as embossed letters. We display the finished assembly of the prototype Geneva Gear stand on the Department’s 3-D Printing Hall-of-Fame exhibition with the students’ names on them as a memory of the class.
Figure 8: Sample Geneva Drive Display Stand
4. Discussions and Conclusions
The introductory 3D printing course presented in this paper has been in place and taught in the elective course every winter term at the Department of Engineering Technology at Miami University. With the hands-on lab activities, the students are introduced to the processes of 3-D modeling, scanning, prototype proof-of-concept model development as well as a variety of 3-D printing techniques throughout the diverse body of equipment used. In addition to supporting engineering technology courses, the introductory 3D printing course is also helpful to students from various majors other than engineering technology. For over the past three years, about 40% of the enrollment of the course have been by non-engineering or technology students. Students
from disciplines such as health information technology, computer information technology, business and creative arts have expressed interest in this course and they reportedly utilized what they learned in this course in building prototypes for their research and class projects in their disciplines. The added value of the 3-D printing course at Miami University is the reality that it allows students to be exposed to the understanding of the behavior and performance of different materials used in 3-D printing processes.
Based on what we learned from the informal surveys and end-of-semester evaluations carried out for this course, the learning experiences of the students taking the presented 3-D printing course were overall very positive. All the students enrolled in the introductory 3-D printing course successfully created the 3-D CAD model assignments and most students successfully printed their prototypes using the 3-D printers in the AM Lab. Some students initially had one or more errors in their completed parts, and only four students made changes to their drawings once given the corresponding model.
The following are some of the student responses/comments recorded via the student surveys and evaluations on a question entitled: “Which aspects of this course/instructor led to a valuable learning experience”?
● “I value the hands-on experience of learning the software and then being able to have the software with me to practice once the semester is over. I love how we have the 3D printer in Miami University and don't have to travel to see them we can see them in the same building the class is in.”
● “The course was well-organized; the instructor was very in depth and allowed for a ton of Q&A. Overall great information on the topic of the course”
● “Hands on labs”
● “It was beneficial to learn to use the software and be able to actually see the operation of several different 3-D printers”
● “Learning the history and the future of 3d printing. I didn't know there is different types and methods of 3-D printing. I thought it was helpful in knowing because it could be a business venture in the future”
As we continue offering this course, we will develop new materials and modules to deliver to the students. We also plan to collect and publish more formal assessment data with a standard
grading protocol in future iterations of the lab activities to demonstrate the effectiveness of the course in technology education.
Acknowledgements:
The development of the AM Lab used for this class project was partially funded by grants sponsored by both the Ohio Department of Higher Education (ODHE) and the Armin J. Fleck Trust.
References
[1] T. Serdar, “Educational Challenges in Design for Additive Manufacturing”, Paper presented at 2016 ASEE Annual Conference & Exposition, New Orleans, Louisiana. 10.18260/p.27294
[2] G. Pahl, and W. Beitz, “Engineering design: a systematic approach”, Springer Science & Business Media, 2013.
[3] G.M. Nannan , C. Leu. “Additive manufacturing: technology, applications and research needs”, M.C. Front. Mech. Eng. 8: 215. 2013. doi:10.1007/s11465-013-0248-8
[4] ASTM, (2009), ASTM International Committee F42 on Additive Manufacturing Technologies, ASTM F2792–10 Standard Terminology for Additive Manufacturing Technologies, ASTM, West Conshohocken, PA.
[5] M. Bal and A.O. Abatan, "Developing Additive Manufacturing Laboratory to Support Instruction and Research in Engineering Technology", Proceedings of ASEE 2017 Annual Conference and Exposition, June 2017, Columbus, OH.
