Automation of a Glow Discharge Spectrometer
Sponsor: Professor Kenneth Vecchio
Embedded Files
Fig 1.1: LECO Glow Discharge Spectrometer (GDS900)
Figure 1.2: Photo of the final prototype
MAE 156B: Senior Design Project (Spring 2024)
David DeHaro, Eric Montejo-Francisco, Louis King, and Micah Cerros
GDS Automation Process.mp4Video outlining the automation process of a LECO Glow Discharge Spectrometer (GDS900).
Team 4 Posterboard - FINAL DRAFT.pdf
156b Report FINAL DRAFT- Team 04.pdfProject Background
Project Background
Professor Kenneth Vecchio's research lab in UCSD's nanoengineering department focuses on advanced material discovery. They employ a "High-Throughput Rapid Experimental Alloy Development" (HT-READ) methodology in which AI helps create a material composition, which is then fabricated using a metal 3D printer. The chemical composition of the 3D printed alloys must be verified through the use of a LECO Corporation Glow Discharge Spectrometer (GDS900, see figure 1.1), and the results are fed back to the AI for further material refinement. The loop continues until the optimization of the composition is reached.
Sets of these alloy samples are contained on disks, resembling “wagon-wheel” like shapes, where each “spoke” is one sample (figure 1.3). Previously, a postdoctoral researcher working in Professor Vecchio's lab, Dr. Haoren Wang, would manually align each spoke to a 9mm diameter O-ring on the spectrometer (figure 1.4) and then begin analysis. The goal of this project was to design, manufacture, and program a system to automate the process of analyzing every sample on one wagon-wheel to increase the efficiency of the alloy development process as well as allow Dr. Wang's workflow to be less tedious.
Figure 1.3: "Wagon-wheel" shaped alloy samples.
Figure 1.4: Sample placement location within the GDS. The O-ring where the spokes of the wagon-wheel must be placed is shown in blue.
Functional Requirements of Project
Functional Requirements of Project
Hardware Goals
Hardware Goals
Create a robotic mechanism that can align and place every spoke of both wagon-wheels on the GDS O-ring for measurement.
Enable the mechanism to move the sample away from the O-ring between every measurement in order for the GDS to perform self-cleaning.
Allow for easy sample loading and unloading.
Software Goals
Software Goals
Allow the user to start the measurement process by clicking a button once the sample is loaded.
Establish communication between the designed device and the GDS in order to synchronize sample placement, analysis, and GDS self-cleaning.
Retract the sample to a safe position and alert the user of any issues or errors that arise during analysis.
Overview of Design Solution
Click here for a more detailed description of the design and performance results.Overview of Design Solution
Mechanical Design
Mechanical Design
Figure 1.5: Full CAD of mechanical design of the prototype (left) and implementation within the GDS (right). The GDS components are shown in pink and the X-Axis Actuation Assembly is omitted of clarity in the right figure.
The designed mechanism consists of a three-axis positioning device and is split into four main components:
- Vertical Z-Axis Ball Screw Slider Assembly
This component is the main base of the mechanism that is mounted inside the GDS. A NEMA 23 stepper motor drives a ball-screw which is used to move the sample up and down along the z-axis direction.
- Horizontal Y-Axis Assembly
This component is mounted on the vertical axis assembly. A NEMA 8 stepper motor drives a lead-screw which is used to move the sample side to side along the y-axis direction.
- Wagon-Wheel Gripper Assembly
This component holds both sized wagon-wheel samples. A spring-loaded arm allows for easy loading of the sample. Additionally, the gripper is mounted on sliders that allow it to move freely in the x-axis direction. The X-Axis assembly along with the cooling puck are used to clamp the gripper and sample against the O-ring, then springs retract the gripper and sample once analysis is complete.
- Into the GDS X-Axis Actuation Assembly
This component is also mounted directly to the GDS. It consists of a rack and pinion driven by a NEMA 23 stepper motor used to push the GDS cooling puck forwards in order to clamp the sample against the GDS O-ring for analysis.
Electrical Hardware
Electrical Hardware
Figure 1.6: Electrical hardware schematic (left), control box with components list (middle).
Figure 1.7: Buttons used to manually jog the mechanism during calibration.
Software Implementation
Software Implementation
The overall architecture of the software – shown in figure 1.8 – functions to synchronize the positioning of the sample alignment mechanism with the analysis and self cleaning of the GDS. A software application developed by LECO (CornerStone) is used to interface with the GDS. An Application Programming Interface (API) send commands to the GDS through CornerStone and communicates with the Programmable Logic Controller (PLC, or Arduino MEGA). The PLC is used to control the motors driving the alignment mechanism.
Figure 1.8: Architecture of software connections.
Figure 1.11: General User Interface (GUI) shown on the PC computer, used to complete calibration, choose wagon-wheel size, start analysis, and handle errors that arise.
Please click here for a more detailed description of the design and a summary. of performance results.
User Manual.pdfPage updated
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