3D Metal-Plastic Printer for Fabrication of Antennas on Custom and Flexible Surfaces

Transcription

1 University of Manitoba Department of Electrical & Computer Engineering ECE 4600 Group Design Project Progress Report 3D Metal-Plastic Printer for Fabrication of Antennas on Custom and Flexible Surfaces by Group 10 Gabriela Teles Kadeem Coleman Jongmin Kim Tyler Duke Yuhao Zhao Academic Supervisor(s) Dr. Cyrus Shafai and Dr. Lot Shafai Industry Supervisors Harris Liontas Novra Technologies Date of Submission January 12, 2015 Copyright 2015 Gabriela Teles, Tyler Duke, Kadeem Coleman, Yuhao Zhao, Jongmin Kim,

2 TABLE OF CONTENTS Table of Contents 1 Introduction Project Progress D Plastic Printer Progress Summary Inkjet Cartridge Integration Progress Summary Antenna Design Progress Summary Future Work D Plastic Printer Future Work Summary Inkjet Cartridge Integration Future Work Summary Antenna Design Future Work Summary Conclusions References Appendix A Updated Gantt Chart Appendix B Updated Budget i

3 1 Introduction 1 Introduction The objective of this project is to design and construct a 3D printer capable of printing highresolution microstrip antennas for research purposes. The printer will be able to print with two di erent types of materials; plastic and metallic ink. An open-sourced 3D plastic printer design is being modified to include a inkjet cartridge that will print with silver ink to serve as the conductor for the fabricated microstrip antenna. To date, construction of the 3D printer has been completed and calibration of the printer is currently underway. Final calibration and incorporation of the inkjet cartridge is scheduled to be completed by the end of January. Antenna design is slightly behind schedule, but work on the design is still scheduled to be completed on time for final completion of the project. A more detailed outline of the schedule can be found in the form of a Gantt chart in Appendix A. 2 Project Progress Our project is composed of two main sections, the 3D printer design and build, and the antenna design and testing. The 3D printer has two main components: the basic plastic printer design, and the inkjet cartridge and carrier. The basic 3D printer is based o an existing open-source design, and an inkjet cartridge will be incorporated to allow the printer to print with multiple materials. The antenna section of our project includes both the preliminary design on High Frequency Structural Simulator (HFSS) software, and testing and comparison of the antenna produced by the printer. The following sections will describe the progress made in each of these sections in detail D Plastic Printer Progress Summary The 3D printer is comprised of a mechanical system for traversing space using a Cartesian coordinate system. It uses a hot end extruder in order to apply the building material to a build platform located in the y-axis. The design of the printer was determined in early October, settling on a 1

4 2 Project Progress pre-existing design (Prusa Mendel) to reduce the initial building and configuration complexity in order to dedicate more time to integrating the inkjet printing system [1]. The first step for this aspect of the project was to build the 3D printer, which was completed over the month of December due to the late arrival of parts from various vendors. This build included setting up the various axes of the printer and testing of all the electrical components such as stepper motors, stepper drivers and end stop sensors to ensure they functioned properly before being included. Over the course of this initial testing it was discovered that the stepper drivers had arrived non-functional so replacements were ordered. Following the build of the printer, testing and calibration of the system as a whole commenced and is still ongoing. To ensure that the system would respond correctly as a whole, it was first necessary to ensure that the system would proceed to its home position (0,0,0) before other steps could be undertaken. Before calibration could take place, the hot end extruder motor had to be calibrated separately from the rest of the motors. Calibrating the hot end extruder has proved di cult and is still ongoing. Calibration of the rest of the machine involves printing a series of objects with known sizes, measuring the printed object, and adjusting the printers motor steps per mm according to the di erence between expected and actual size. A cube has been printed which measures 16x16x8mm; which has indicated the need for further adjustments in order to reproduce the desired 20x20x20mm cube. 2.2 Inkjet Cartridge Integration Progress Summary In order to print with silver ink we required a recyclable cartridge, a carrier to hold the cartridge and a means of controlling the ink deposition with a limited amount of pins available from the Arduino microcontroller. There is limited information available on inkjet cartridges therefore various types were researched. From a donated cartridge received in November, it was determined that in order to control the cartridge nozzles a new printer would have to be purchased in order to determine what signals each pin on the cartridge was receiving while in operation. This method was too 2

5 2 Project Progress complex to complete by our February deadline. Through more research do it yourself (DIY) inkjet printer projects were discovered which referred to components needed to complete the integration of our inkjet head. An HP C6602 cartridge was chosen as the nozzle used to print the silver ink [2]. This cartridge was chosen because it is the only cartridge that has specifications available to the public. This cartridge has a HP Q2347A carrier available for purchase and open source software for interfacing this specific cartridge and carrier combination with an Arduino. In December, the cartridge type was decided followed by design and simulation of the electric circuit used to interface the Arduino and the cartridge. The circuit is based o of a DIY printer design and includes; a power reduction circuit, carriage safety circuit and a pin reduction circuit. The design of the power reduction circuit was based o of a circuit provided in the LM317T adjustable regulator datasheet [3]. Multisim software was used to run a simulation to ensure that the circuit worked. Construction of the power reduction circuit resulted in successfully converting the 32 Volt (V) supply to 20 V; this is required to power the cartridge. To eliminate random voltages from the Arduino being sent to the carrier and causing misfiring of the inkjet nozzles when not in use it was determined that the power to the carrier needed to be cut. An optocoupler was purchased to allow us to turn the 20 V supply to the cartridge on and o by utilizing pins on the Arduino. In the design we included a LED to provide indication of when the switch is on or o. The HP C6602 cartridge prints using 12 nozzles and due to the limited pins available on the Arduino a pin reduction circuit was designed [2]. A 16-channel analog demultiplexer was purchased to allow us to control the nozzles of the HP C6602 cartridge, using 4 pins. Since the cartridge pins operate at a higher voltage then the rated voltage for the demultiplexer, high voltage darlington drivers comprised of eight NPN darlington pairs was purchased to allow us to connection of high voltage components to low voltage components. 3

6 3 Future Work 2.3 Antenna Design Progress Summary The antenna design was divided into two main steps. The first step was to obtain the dimensions of the patch, location of the feeding point and the radiation pattern using empirical formulas coded in MATLAB [4]. This work was completed within the first two months of the project. In the second step, design results from step one were used as a starting point to design the microstrip antenna in HFSS simulation software. Using HFSS the antenna design was optimized by assuming specific conditions. The first set of conditions included Perfect Electric Conductor (PEC) metallic conductors, a lossless dielectric substrate and an infinite ground plane. The antenna patch size was optimized to attain the desired resonant frequency and the feeding point was adjusted based on best impedance matching. A simulation with these first set of conditions was completed by the end of October. The second set of design conditions were similar to the first, except the ground plane was reduced to a finite size to make the antenna fabrication of the designed antenna practical. The size was chosen to be 0.7 times the free-space wavelength at resonant frequency because the actual permittivity of the substrate is unknown. Both simulations have been completed and the results recorded. This simulation was completed by the end of the first week of January. Another set of conditions has yet to be tested and simulated, and this will be discussed in the future work section of the report. 3 Future Work The following sections outline the work to be completed for the project D Plastic Printer Future Work Summary The work remaining on the 3D plastic printer is all related to calibration of the system. Calibration is currently ongoing as we have yet to print a completed object of a given size. Once this is complete 4

7 4 Conclusions integration of the inkjet head can begin. 3.2 Inkjet Cartridge Integration Future Work Summary Fully incorporating the inkjet head into the existing plastic printer design is set to be completed by the end of January. This includes adjusting the design of the cartridge carrier to work with our existing system. Once this is complete, the remaining work will be to calibrate and test the full system, as well as print our antenna. The complete design will also require integration of a halogen lamp. The lamp will be used to cure the silver ink without having to remove the antenna in-between layers. 3.3 Antenna Design Future Work Summary For future work, final simulations and antenna testing will be completed. This involves antenna optimization by applying conductivity of conductors, and permittivity and dielectric loss of the substrate. The conductivity of silver ink is related to the resistive loss of the patch and therefore it will also a ect the input impedance of the antenna. Knowing the conductivity of silver ink is critical to matching the antenna. The silver conductor is first printed over a surface (i.e. paper or plastic film) and then allowed to dry under a halogen lamp. The conductivity of the conductor can be found by knowing the dimensions and electrical resistance of the conductor. The permittivity and loss tangent of the substrate can be obtained using a ring resonator technique [5]. Antenna testing involves pattern measurement and gain measurement using antenna measurement chamber and impedance mismatch measurement using Vector Network Analyzer (VNA). These tests will be performed to test the quality of the 3D printed antenna once the antenna is successfully fabricated. 4 Conclusions To summarize, the basic plastic printing design of our 3D printer is nearing completion and requires final calibration. The parts required to incorporate the inkjet head into the design are on order. 5

8 4 Conclusions Once the parts are in our possession we will be able to add the inkjet head and begin calibration and testing of the system as a whole. The antenna design, despite being behind schedule, will still maintain it s final completion date as indicated on the Gantt chart. Work in this area is being expedited and we expect to get back on schedule within the next two weeks. 6

9 REFERENCES References [1] Prusa mendel. [Online]. Available: Mendel (iteration 2) [2] N. C. L. Patrick Hannan, Jared Knutzen and J. Markham, Diy inkjet printer, December [3] Ka317/lm317 regulator datasheet, December [Online]. Available: fairchildsemi.com/datasheets/lm/lm317.pdf [4] C. Balanis, Antenna Theory Analysis and Design, 3rd ed. John Wiley and Sons, [5] M. A. Rashidian, Dielectric characterization of materials using a modified microstrip ring resonator technique, IEEE Transactions on Dielectrics and Electrical Insulation, vol. 19, p. 1392,

10 Appendix A Updated Gantt Chart Task/Milestone Planned September 2014 October 2014 November 2014 December 2014 January 2014 February 2014 March 2014 Start End Sep-01 Oct Preliminary Work Research Ink and Printable Materials Sep-01 Sep-21 Research Printer Parts Sep-01 Sep-21 Research Antenna Designs Sep-01 Oct Materials Sep-14 Oct-19 Gather Material List and Pricing Sep-14 Sep-21 Order Printer Parts Sep-28 Oct-05 Order Ink/Printable Material Sep-28 Oct Design Sep-14 Feb-12 Printer Design Sep-14 Oct-05 Antenna Design & CAD Drawing Oct-05 Feb Printer Oct-19 Feb-15 Build of Plastic 3D Printer Oct-19 Jan-11 Interfacing & Calibration Dec-01 Jan-30 Inkjet Cartridge Incorporation Dec-01 Feb Testing & Optimization Jan-11 Feb-30 Prototype Construction Jan-11 Feb-01 Printer Calibration Jan-18 Fab-07 Feb-07 Feb-14 Build & Test of Antenna Control Antenna Testing Feb-07 Feb Administrative Schedule Project Proposal Sep-14 Sep-28 Informal Oral Progress Report Nov-09 Nov-16 Formal Written Progress Report Nov-23 Jan-12 Formal Oral Progress Report Nov-30 Jan-16 Project Title Feb-08 Feb-13 Final Report Draft Submission Feb-08 Feb-23 Final Report Mar-01 Mar-04 Project Presentation Mar-01 Mar-13 Completed Tasks Tasks to be Completed Fig. A.1: Updated Gantt Chart 8

11 Appendix B Updated Budget The budget for this project is $ and is outlined in the table on the next page. $ of the budget is composed of items available for use through the Department of Electrical and Computer Engineering. The remaining $ of the budget was allotted to items required to be purchased through the budget provided by the department. Please Note: *Items that were already provided or were acquired without funds from the budget. **Miscellaneous parts such as resistors and capacitors required for circuit hardware. 9

12 Table I: Project Budget Item Supplier Unit Cost Quantity Shipping Cost Total Electronics Package Sainsmart $ $0.00 $ M8 Threaded Rod Mixshop $ $5.00 $ mm Smooth Bar Mixshop $ $5.00 $24.00 Prusa Mendel Hardware Set Mixshop $ $5.00 $23.50 Linear Bearing Mixshop $ $5.00 $15.80 PLA Printer Filament (Black) Amazon $ $0.00 $32.99 Internal PC Power Supply Amazon $ $0.00 $38.37 Bowden Extruder Hardware Ebay $ $7.00 $30.13 Halogen Lamp Home Depot $ $0.00 $10.98 Refillable Ink Jet Cartridge Transact $ $10.35 $25.80 Cartridge Carrier Transact $ $10.35 $18.60 Wiper Transact $ $10.35 $10.69 Control Antenna Conductor Department $ $0.00 $0.00 Inkshield PCB NicolasLewis $ $3.00 $12.00 Stepper Motor Driver Mixshop $ $0.00 $8.19 *PCB Department $ $0.00 $ *Silver Printer Ink Department $250 1 $0.00 $ MK8 Drive Gear Ebay $ $7.72 $18.32 **Misc. Parts Digikey $ $8.00 $26.19 *Machine Shop Time Department $0.00 8hrs $0.00 $0.00 *HFSS Software Department $ $0.00 $ *Misc. Wood Products Gabriela $0.00 TBD $0.00 $0.00 *HP Desktop Printer Kadeem $ $0.00 $0.00 Total: $