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Andrés Witzke – 1 April 2019
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TECHNICAL PROJECTS LOOKS-LIKE PRODUCT MODEL COMPANY: EKKO AUDIO DATES: July 2016 – August 2016
Ekko Audio's HUB is an audio hub for headphones and speakers. It lets the user instantly share wireless audio with multiple simultaneous listeners using any earbuds, headphones or powered speakers.
For product pitches and investor meetings, the company wanted a looks and feels-like model. I was part of the team designing the "puck" component. Together with electrical engineers, and after multiple iterations, the design was finalized and sent to production.
CAD Model for 3D Printing
The main challenge of this project was maintaining constant and clear communication with the electrical engineers in order to determine the physical location of the top button, USB port, headphone jack, battery and lights.
In this prototype, I made the model as versatile as possible by 3D printing all the components (including mock prints for the electrical ports for tolerance purposes) and included thin disks that could be stacked in order to adjust the height of the circuit board.
Andrés Witzke – 1 April 2019
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SILICONE SKIRT SEAL COMPANY: Zombait DATES: July 2016
Zombait is a robotic fishing lure that keeps bait kicking like it is alive to catch Tuna, Billfish, Stripers, Tarpon, Wahoo, and more.
The product needed a silicone skirt to smooth the interface between the main body and the moving tail. The project consisted of designing a mold for a silicone skirt that would seal the gap between the actuated section of the product and the main body. Once designed, the mold and the core were 3D printed and, using Smooth-On silicone, the skirt was made.
Right to left: Mold, core, final blue silicone skirt after curing and assembled on the product.
The main challenge was minimizing the air bubbles trapped between the core
and the mold during the curing process, since the skirt is thin. To solve this, the mold was shaped so that it would fit inside a pressure chamber. The Smooth-On was poured, the mold put in a vacuum, and then fitted inside the tubular pressure chamber. It can make four skirts simultaneously, and three molds can be stacked in the chamber, maximizing time. These molds were used to make the skirts for the initial hundred units.
Andrés Witzke – 1 April 2019
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CATHETER MANUFACTURING PROCESS COMPANY: Fractyl Laboratories DATE: January 2017 - May 2017 I had the opportunity to work with Fractyl Laboratories, a medical device company that is focused on developing procedures to help patients with Type 2 Diabetes and NASH. Their main product is an oral catheter that chemically rebuilds the wall of the duodenum in order to improve insulin secretion. This project consisted of creating a new manufacturing process for a dual-flexibility catheter tube.
The process thermally welds two separate polymer catheter shafts of different flexibilities to create a composite shaft that improves the device ease-of-use and the patient's safety during the procedure.
Weld Housing
Main Equipment: Vante Jade (CAD Model by me)
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The design of this manufacturing operation included: • The selection of machinery: Based on the company’s goals and budget, I
performed a market study and built a proposal for the purchase of the equipment. • Inspection processes: to maintain the integrity of the final product, my colleague
and I built four separate inspection processes from scratch. This included designing fixtures for testing dimensions, pressure capability, proneness to kinking and the tensile strength of the weld.
• The manufacturing process: I studied the technology and designed production-grade fixtures in order to integrate the process into the manufacturing line.
The development of this process allowed Fractyl to eliminate outsourcing on two catheter post-extrusion operations. Representing significant cost savings and further streamlining the process.
RF Coil
Weld
Cross Section View of the Weld Housing
Rigid Shaft
Flexible Shaft
Andrés Witzke – 1 April 2019
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Final Product
An example of the fixtures designed for production
Andrés Witzke – 1 April 2019
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REDBULL FLUGTAG GLIDER COMPANY: MassChallenge DATES: August 2016
Through MassChallenge I was able to take part in the design and construction of the craft to be used in the Redbull FlugTag competition in Boston. Except for safety specifications, there weren't any clear instructions by event organizers on how the flying vehicle could be designed. After doing some research, I chose the Rogallo style glider based on practicality and safety since there would be a human pilot. Other factors heavily considered were cost, modularity and ease of assembly.
Initial CAD Model After creating a digital outline of the design, I calculated the amount of aluminum
needed. I chose aluminum because of its light weight and low cost, as well as its ease of machining. Due to transportation constraints, I sectioned the 20ft wingspan glider into modules and welded them strategically so that it would be rigid yet packagable. Brackets were used to join the welded parts together.
Andrés Witzke – 1 April 2019
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The final weight of the aluminum structure was 71 lbs. It was wrapped in vinyl tarp and successfully mounted onto the launching vehicle.
Final Build and Glider in action.
Despite the unfortunate head-on wind gust at the moment of launch, we placed fifth in the competition, and most importantly, our pilot was safe.
Andrés Witzke – 1 April 2019
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SUBMERSIBLE LEDs FOR ALGAE GROWTH UNIVERSITY: RENESSELAER POLYTECHNIC INSTITUTE DATE: June 2015 – August 2015
I lead a group of student researchers in a project for the Light Enabled Systems & Applications (LESA) Engineering Research Center headquartered in RPI. Using iterative design and testing often to assure we met the requirements, we designed and assembled induction driven generators and coupled them with voltage amplifying circuits and LEDs to be used in the harvesting of algae.
The future goal of this project is to submerge these generators inside a harvesting tank, and - by harnessing the kinetic energy from the turbulence of the water; the light emitting generators can be used to grow algae.
Below are some pictures of the work, followed by the final research poster. Above: Testing apparatus I designed to measure the voltage generated from the kinetic
energy of shaking the induction generator. Below: Final generator. 3D printed structure together with amplifying circuit and LEDs.
Andrés Witzke – 1 April 2019
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ORION CART UNIVERSITY: Boston University DATES: February 2016 – May 2016
CAD Model This project consisted in improving the common grocery cart. The goal was to make it easier for elderly users to overcome stairs and other obstacles, and to assure the safety of the user and the cargo in the process. The design was comprised of three systems:
• Climbing Mechanism: By using a triangular configuration of three wheels in each end of the axle (below, right), the force required to climb upstairs is much lower than a traditional two-wheel setting (below, left).
Climbing Profiles: Left, traditional. Right, Orion Cart.
Tradi Ori
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• Pivoting Basket: Allowing the basket to pivot assures the center of gravity of the cart will always be ahead of the axle. If dropped, the cart only falls forward, keeping the groceries in the basket.
Center of gravity of basket stays in front of axle and towards the staircase • Braking Gear System: The linked gears along the individual and main axles
make it so only one of the gears needs to be engaged for the system to brake in case the cart is dropped.
Left: Modeled gear system, Right: Prototype
