Arthrex Internship
Aug. 2022 - Nov. 2022
General Overview
After graduating from the University of Florida in spring of 2022 and working for the Human Neuromechanics Lab during summer of 2022, I joined Arthrex as a test engineering intern within the Imaging and Resection (I&R) department in August of 2022. During my three months at Arthrex, I was a part of various different projects, which can be grouped into four main categories: testing, documentation, design, and miscellaneous.
Project Categories & Results
Testing
Most of my internship entailed testing three Arthrex products in the I&R lab: the RF probes, the DualWave Outflow Tube Sets, and the DualWave Pump Remotes. Each test had a specific test protocol, which detailed how to set up and execute test experiments. My responsibility as the test engineer was to follow the test protocol, record the test results, and report my findings back to the design engineers.
For the RF probes, I executed a total of eight different test protocols with my mentor: water leakage testing, leakage current testing, dielectric strength testing, fluid ingress testing, longevity testing, temperature testing, continuity testing, and clog testing. Each of these tests had unique setups and troubleshooting issues that my mentor and I solved as we conducted each test. As a result of performing all of these tests, I got to use a pressure gage to determine if the probes could withstand water at a certain psi (water leakage testing), an oscilloscope and Hipot tester to push current through the probes to see if they could withstand a certain voltage (leakage current and dielectric strength testing), an LCR meter for checking the probe impedance before and after water submersion to determine button functionality (fluid ingress and continuity testing), thermocouples to determine probe temperature at various locations on the probe while ablating (temperature testing), and a custom, three-axis robot with prewritten G-code to determine how long and how well the probe could ablate in tissue (longevity and clog testing). An image of the RF probe can be seen below.
For the DualWave Outflow Tube sets (seen below on the left), I performed a leak and kink collapse test with another intern to determine if the tubes would leak water or create a kink when pumping water through the system using the Dualwave Arthroscopy Pump (seen below on the right). I also preformed flex testing at a certain location on the tube set to determine if the tubes could withstand bending at 120° and 180° (clockwise and counterclockwise) at 150 cycles and 50 cycles, respectively. I used a pre-written Arduino code and a custom test fixture to perform the flex test.
For the DualWave Pump Remote (seen below), I tested each of the buttons on various remote samples to determine if they could activate different arthroscopy pumps and transmit the appropriate number of volts when activating each button.
Regarding results, I completed each test protocol on time and efficiently, recording all test findings and following Arthrex’s good documentation practices (GDP) when documenting test findings.
Documentation
After each test protocol was completed, a summary and report needed to be written, detailing the results of the experiment. Since the RF probe test protocols were primarily my mentor’s projects (I was tasked by my supervisor to assist her in all protocols/tests), I did not write any summaries or reports for those tests. However, for the flex testing and pump remote design verification tests, I documented the test results and findings in a summary and completed the report myself since those two projects were my responsibility alone.
Design
Towards the end of my internship, I was tasked with creating a test fixture to that could be used to perform a surface roughness test on RF probe electrodes. The fixture would be mounted onto a KEYANCE device to perform the test, so my primary requirements were to ensure that the fixture was under 8 cubic inches and that the fixture would be able to secure the electrode in a flat, fixed position for the test.
I designed two versions of the fixture, which can be seen below. One version can hold one electrode at a time whereas the other can hold two at a time. I designed the fixture using the cavity feature on SOLIDWORKS, modifying the cavity to ensure just enough space within it for the electrode to slide into (without too much clearance) and using two points of contact so the electrode’s top surface remained parallel with the top surface of the fixture. Since the electrode has a tapped hole in it (not seen below), I made sure to include a hole in the fixture so that the RF probe’s threaded rod could be placed into that hole and screwed into the electrode, securing the electrode into a fixed position. Once designed, both versions of the fixture were 3D printed and placed under a microscope to make sure the electrode’s top surface was parallel to the surface of the fixture.
Miscellaneous
During my internship, I also performed other, smaller tasks such as redesigning a camera mount for one of the test fixtures using SOLIDWORKS, modifying the clog test fixture by adding certain features to one of its components on SOLDIWORKS and 3D printing it, soldering wires on a test fixture to improve functionality, and making modifications to the flex test fixture to reduce noise under operation.
Shortcomings & Lessons Learned
For almost every test protocol that was executed, some sort of issue would arise. I do not believe any of them went as smoothly as the protocol suggested they would, which meant that there was plenty of troubleshooting throughout the process. On one side, this proved annoying considering that some of the protocols needed to be completed as soon as possible. However, each issue was an opportunity to brainstorm and critically think about how the problem could be solved. Each protocol provided a nice exercise in improvisation and learning how to quickly and efficiently solve unexpected issues.
While 3D printing the test fixture, I learned about print orientation, and how it can influence the functionality of the print. When I created the final version of the test fixture, I sent out two copies to be printed without specifying the direction I wanted the layers to be printed in. I ended up with two different print orientations, which can be seen below.
I noticed that with horizontally printed layers, the electrode slid into the fixture perfectly with no slack. However, with vertically printed layers, I had to pick away at support material within the cavity to get the electrode to fit in it. I realized that for this design, specifying horizontally printed layers prevented additional material from forming in the cavity due to the contours within the cavity. Additionally, I also learned that photopolymer filament was best for this application since the test fixture needed very small, precise dimensions for the cavity to have just enough clearance to allow the electrode to sit within it.
Overall Experience & Skills Attained
Despite the internship lasting only three months, I learned so much during my time here. I learned about the various ways Arthrex tests their products within the I&R department (also getting to see each of those devices used by surgeons during cadaver lab demonstrations), how to troubleshoot issues quickly and efficiently to encourage project completion, good documentation practices when writing summaries for reports, and how to use various different electro-mechanical devices and test fixtures in the lab. I also gained additional experience in design and soldering, and I attended a few career-development classes during my time at Arthrex. Overall, it was an incredible experience, and I am very grateful to have spent this time working with great people at a fantastic company.