Hi! Welcome to my portfolio page. Here’s my latest resume. This page showcases some of the things that I’ve worked on professionally, that may not be well described in a resume.
Interested? Please reach out - ttstam@gmail.com.
STAMP & Elrond - Industrial Automation
This pair of robotic work cells are capable of testing and calibrating 800 sets of toothbrushes every hour. I designed all the fixtures on the machines, as well as the palletized handling system that the machine runs on. Because of the unique clamping requirement for calibration, the pallet is designed to be lifted up and located from the bottom while specialized grippers grip the DUT and lift the DUT off the pallet for calibration. A dummy load that simulates the moment of inertia of a toothbrush head is then applied. Through pogo pins that contact the PCA, the machine drives the brush head through a range of frequencies while a Keyence laser measuring system measures the vibration amplitude. The computer then selects the drive frequency that results in the maximum amplitude displacement and programs it into the DUT. Finally, at the next station, the overload condition is calibrated into the handle and when everything passes, a solder joint is made on the DUT to electrically connect the battery.
STAMP, the first machine, was designed in about 2 months. The project kicked off in June and by August, we were building the machine in China. It was installed and commissioned at the factory by the end of October. Elrond, the second machine, was designed in under a month. We received the PO about 2 weeks before Halloween and by the first week of the new year, the machine was built, installed, and commissioned at the factory. There are now 3 sets of these machines running at various locations around the world, and every one of the client’s toothbrushes passes through one of these machines before leaving the factory.
As a bonus, I shot the raw footage above as well for my video editing team.
AR Glasses SLAM camera calibration fixture
This is an 11-axis end effector for a GP7 robot, designed to exercise an AR glasses’ set of SLAM cameras for calibration. Five of the axis are for positioning the two eyeball cameras looking through the AR display lens, while the other 6 axis puts a controlled and repeatable flex on the AR glasses. A 6-axis load cell in each side measures the force applied to the DUT during the calibration procedure.
The GP7 robot has a 7kg payload limit, with 2kg taken up by the DUT. To meet the weight requirement, extensive FEA was performed to strategically remove weight from the machined parts. Finally, the base plate was machined out of magnesium alloy (62% the density of aluminum!) for further weight saving. We came in under the weight limit that we were allocated - no small feat given the weight of the 11 linear actuators and supporting Renishaw encoders.
Home-built multi-material 3D printer
The machine’s carriage consists of a kinematic (Maxwell) coupling with a cable actuated lock. It is capable of automated print head changing. I built it to get experience in multi-material 3D printing and to learn more about computer vision systems (the machine uses an optical microscope for print head position calibration).
Drone propeller and drivetrain testers
These are a pair of testers for qualifying drone propellers and drivetrain motors. I owned the mechanical engineering and supported the systems engineering of the testers, including measurement accuracy, vibration reduction, and fixture V&V.
Just for fun…
A friend of mine gave me his hand-me-down Peg Perego Gator. I modified it to run on Ryobi 18V batteries, then added pneumatic tires and a variable speed throttle instead of the bang-bang controls that it came with. My sons helped along the way. With grippier pneumatic tires and the ability to vary the throttle, it can traverse my hilly backyard without issues.
Facial recognition camera system
I lead the hardware team developing a facial recognition system for a major theme park. I helped the client develop their specification of the system, verify their assumptions with quick turn prototyping, and then worked with the industrial designer to package the cameras and optically laminated display. I also identified an issue with the IR lighting for the facial recognition system (pertaining to test subjects wearing glasses) and lead the efforts to resolve it.
The final design features a capacitive touch screen optically laminated to 4mm thick ion-strengthened glass, with a magnetically attached LED light ring that hides the screws.
Glowforge
I was employee #20 at Glowforge, assigned to the air filter project. The original goal for the Glowforge air filter was a thin “pancake” air filter that sat underneath the Glowforge. Both from a UX and physics perspective, this was not a well considered product - but I was told to implement it anyway.
Within a week of starting on the job, I was able to prove that the air filter that they were about to launch $1 million in tooling for, based on computer simulations, wouldn’t work. Within a month, I was able to prototype and validate an air filter cartridge design that did work. I then built up their air filter test lab and was able to create a working prototype, squeezing the filter cartridge into the compact space underneath the Glowforge, though the product never made it to market.
Test Fixtures
I architected and built the building blocks for a modular test fixture system. At the time, my employer did not have good manufacturing capabilities, so the system was designed to be modular and leverage off the shelf optical fixturing components, and we leaned on overseas manufacturing partners for part manufacturing. Here, it is configured for a major athletic apparel maker for testing a self-lacing shoe module.
Robotic Air Hockey Table for Microsoft
I lead a team developing a robotic air hockey table. Upon reviewing the robot’s specifications, I proposed a custom-built gantry that trades positioning accuracy for speed. We ultimately ended up with an off-the-shelf robot gantry. The results aren’t as impressive as I would have liked, as seen in the video.
More videos are available here.
