Brigham Young University BYU ScholarsArchive Theses and Dissertations 2020-08-13 Modular 3D Printer System Software For Research Environments Clayton D. Ramstedt Brigham Young University Follow this and additional works at: https://scholarsarchive.byu.edu/etd Part of the Engineering Commons BYU ScholarsArchive Citation Ramstedt, Clayton D., "Modular 3D Printer System Software For Research Environments" (2020). Theses and Dissertations. 8688. https://scholarsarchive.byu.edu/etd/8688 This Thesis is brought to you for free and open access by BYU ScholarsArchive. It has been accepted for inclusion in Theses and Dissertations by an authorized administrator of BYU ScholarsArchive. For more information, please contact [email protected], [email protected]. Modular 3D Printer System Software For Research Environments Clayton D Ramstedt A thesis submitted to the faculty of Brigham Young University in partial fulfillment of the requirements for the degree of Master of Science Greg Nordin, Chair Adam T. Woolley Philip B. Lundrigan Department of Electrical and Computer Engineering Brigham Young University Copyright © 2020 Clayton D Ramstedt All Rights Reserved ABSTRACT Modular 3D Printer System Software For Research Environments Clayton D Ramstedt Department of Electrical and Computer Engineering, BYU Master of Science The Nordin group at Brigham Young University has been focused on developing 3D printing technology for fabrication of lab-on-a-chip (microfluidic) devices since 2013. As we showed in 2015, commercial 3D printers and resins have not been developed to meet the highly specialized needs of microfluidic device fabrication. We have therefore created custom 3D printers and resins specifically designed to meet these needs. As part ofthis development process, ad hoc 3D printer control software has been developed. However, the software is difficult to modify and maintain to support the numerous experimental iterations of hardware used in our custom 3D printers. This highlights the need for modular yet reliable system software that is easy to use, learn, and work with to adapt to the unique challenges of a student workforce. This thesis details the design and implementation of new 3D printer system software that meets these needs. In particular, a software engineering principle- based design approach is taken that lends itself to several specific development patterns that permit easy incorporation of new hardware into a 3D printer to enable rapid evaluation of and development with such new hardware. Keywords: SLA 3D printing, microfluidics, lab on a chip, system software architecture ACKNOWLEDGMENTS Thank you to my advisor Dr. Greg Nordin and my parents Greg and Susan Ramstedt, whose constant stream of support, encouragement and good ideas made this thesis possible. CONTENTS List of Tables ........................................ xi List of Figures ....................................... xiii Chapter 1 Introduction ................................. 1 Chapter 2 Background ................................. 5 2.1 How SLA 3D Printing Works .......................... 5 2.1.1 Resin and light .............................. 5 2.1.2 Focus Calibration ............................. 6 2.1.3 Electronics ................................ 7 2.2 Previous Attempts at System Software ..................... 7 2.2.1 Desktop Application ........................... 7 2.2.2 Web Application ............................. 9 2.2.3 Summary of Lessons Learned ...................... 12 Chapter 3 Simplified Architecture Description .................... 19 3.1 Tools ........................................ 19 3.1.1 Coding Languages ............................ 19 3.1.2 Operating Systems ............................ 20 3.1.3 Web Server ................................ 21 3.1.4 Configuration and Print Settings Files . 21 3.1.5 Frontend Framework ........................... 22 3.1.6 Unit Testing ............................... 23 3.2 Simplified Architecture Description ....................... 23 3.2.1 Web Server ................................ 24 3.2.2 Frontend ................................. 25 3.2.3 System Software Core .......................... 25 3.2.4 Backend .................................. 27 3.2.5 Putting it all together .......................... 28 Chapter 4 Detailed Architecture Description ..................... 31 4.1 Starting and stopping the backend ....................... 31 4.2 Structure of the message router process ..................... 32 4.2.1 Handling web server messages ...................... 34 4.2.2 Forwarding messages ........................... 36 4.3 Print job process ................................. 38 4.4 Hardware processes ................................ 40 4.5 File system usage ................................. 41 4.6 Summary ..................................... 42 iv Chapter 5 The Structure of the Code Base ...................... 47 5.1 main.py ...................................... 48 5.2 Messages ...................................... 52 5.3 Process Interfaces ................................. 58 5.3.1 Light Engines ............................... 58 5.3.2 Axes .................................... 70 5.3.3 Print job controller and print job file validator . 74 5.4 Web server .................................... 81 5.5 Configuration Management System ....................... 84 5.6 Tests ........................................ 90 5.6.1 Driver tests ................................ 90 5.6.2 Processes ................................. 91 5.6.3 API .................................... 94 5.7 Final thoughts .................................. 94 Chapter 6 Development Patterns ............................ 97 6.1 Adding hardware ................................. 97 6.1.1 Pattern 1: creating a driver for an existing interface . 98 6.1.2 Pattern 2: creating a new hardware interface . 99 6.1.3 Pattern 3: adding new controller interfaces . 102 6.2 Summary ..................................... 103 Chapter 7 Conclusions and Future Work . 105 7.1 Conclusions .................................... 105 7.2 Future Research .................................. 106 7.2.1 Integration into production research 3D printer . 106 7.2.2 Replace Flask’s development web server with a dedicated web server 106 7.2.3 API handler refactor . 107 7.2.4 Logging .................................. 108 7.2.5 File browser ................................ 108 7.2.6 Impact assessment and prospects . 108 References .......................................... 111 Appendix A Appendix ................................... 113 A.1 main.py ...................................... 114 A.2 ABC_Message.py ................................. 119 A.3 light_engine_message.py ............................. 121 A.4 system_messages.py ............................... 134 A.5 LightEnginesInterface.py ............................. 139 A.6 ABC_LightEngineDriver.py . 148 A.7 LightEngineDummyDriver.py . 155 A.8 AxisDummyDriver.py .............................. 165 A.9 AxesInterface.py ................................. 172 v A.10 PrintJobController.py .............................. 180 A.11 server.py ...................................... 206 A.12 LightEngineBrightness.py ............................ 216 A.13 ConfigManager.py ................................ 219 A.14 config_schema.json ................................ 226 A.15 AxesInterfaceConfig.py .............................. 231 A.16 ABC_AxesDriverConfig.py . 234 A.17 AxisDummyDriverConfig.py . 238 A.18 axes_driver_schema.json ............................ 239 A.19 axes_dummy_driver.json ............................ 241 A.20 grbl_test.py .................................... 242 A.21 test_MessageRouter.py .............................. 244 A.22 Publisher.py .................................... 247 vi LIST OF TABLES 6.1 Table used to find all of the edge cases in the GUI components for the printjob controller web UI. ................................... 103 vii LIST OF FIGURES 2.1 10 µm layers stacked on top of each other as viewed under a scanning electron microscope. The dimples along the layers indicate individual pixels from the cross sectional image. ................................. 14 2.2 3D printed microfluidic pump. The grid pattern is a by product of the individual pixels in the layer images. .............................. 15 2.3 Illustration of a cross-sectional layer of a 3D print being projected as an image onto the build platform of the Asiga Pico Plus 3D printer. Grey pixels are turned off and yellow pixels are turn on. Our recent custom 3D printers operate onthe same principle but do not have the pixels rotated 45◦. Image used with permission from [9]. ........................................ 15 2.4 Layer-by-layer fabrication process for a simplified device. The device is rotated 180◦in (D) relative to (A-C). Image used with permission from [9]. 16 2.5 CAD model of a SLA 3D Printer .......................... 17 2.6 Model-View-Controller Architecture ......................... 18 3.1 3D Printer System Software Simplified Architecture . 23 3.2 Backend architecture for a 3D printer ........................ 26 4.1 Threads used in the message router process to service a light engine api request. Threads that are directly adjacent to each other have a parent-child relationship to each other, with the thread with the largest circle being the parent. Numbered connections relate to the explanation in section 4.2.1 and correlate to Figure 4.2. 33 4.2 State of the job queue for servicing an API call in Figure 4.1. See sections