Gordon Robertson
Custom Shampoo Production Cell
The Task
Working for élan unlimited, I was told to design the mechanical portion of their custom shampoo production cell.
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The cell had to take a bottle, place it under nine separate pumps where portions of the custom shampoo would be added, and then return the bottle so it can be shipped.
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It had to be nearly automated, with minimal human interaction for sanitary reasons
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It had to be highly compact
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It should be easy to manufacture, assemble, and test
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Appear professional for potential investors
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It should be cheap
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Design and production will be almost entirely remote.
Testimonial on my work
I had a lot of fun working on this project with élan unlimited. At the end of this project, Russ Dancho, the Chief Production Officer gave this testimonial
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I recently had the pleasure of working with Gordon on the development of a production cell for a startup that I'm working with. We are custom-mixing hair care products and needed an inexpensive, reliable automation cell. The cheapest reliable peristaltic pumps we could find cost $150, so Gordon designed and 3D printed a pump for about $10 that used skateboard bearings and standard hardware. He worked with us to optimize the design of the pump parts and printed parts when our printers broke down. He was immediately responsive throughout our process, usually turning around change requests overnight.
Gordon also designed the overall layout and structure of the production cell, arranging a large amount of complicated componentry in a very small space. He designed the support structure and tubing guides thoughtfully and adjusted them as our design evolved. As with the pump designs, Gordon's work was excellent - he turned around designs very quickly and his work was uniformly excellent.
I recommend Gordon highly for a lead engineering role in your company. He's an excellent designer, a whiz on CAD, responsive, and easy to work with.
Sincerely,
Russ Dancho
Chief Production Officer
élan unlimited, Inc.
Initial Approach
I started the project by making numerous sketches of the overall cell as well as individual portions.
These served a dual-purpose, letting me brainstorm possible solutions and providing an easy way to get feedback on my design and make sure I fully understood the task.
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The design I ultimately chose used a turntable with 10 discrete locations and a series of pumps suspended above the bottle.
This led to the next task.
Peristaltic Pump Design and Manufacturing
The biggest challenge of this project was designing custom peristaltic pumps
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Going into it, I mapped out the constraints the pumps had to meet.
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They should be easy to assemble
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They should be easy to manufacture
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They should be light and sturdy
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They must be able to be manufactured using only a 3D printer and basic tools
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They have to work with the specified tube, beams, and stepper motor
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They have to be easy to install and maintain from above.
As I had never made a peristaltic pump before and had limited experience with them, the first step was doing some market research on other pumps.
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From there, I found pumps with features that matched what I wanted, such as a model that was easy to operate.
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The first step was creating and iterating upon rough models for the pump. These could be easily printed and tested, allowing me to rapidly iterate on ideas and make sure I was headed in the right direction.
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Once I had a sufficiently detailed design, the next step was characterizing the 3D printer being used.
I designed and sent over various test parts that let me quantify the needed tolerancing and achieve very tight fits.
With these tolerances, I could move onto the stage of iterating, testing, and finalizing the layout of the pumps.
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Due to the rapidly changing nature of working in a startup, I spent a significant amount of time going back over my parts within the CAD and making sure that they were well documents and easily defined. This let me rapidly and efficiently adapt to changing specifications.
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Ultimately, the final design of the pumps had the following effects
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Using 3D printed materials allowed for ten-fold cost savings
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The pumps are easy to fit together and the tubes can be changed from above
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The PLA used could be easily purchased in different colors, allowing for a visually appealing pump
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The pump itself is made up of only five printed parts, making it easy to print and assemble
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Turntable Design
Now that the pumps were designed, I could focus on finalizing the design of the turntable.
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I refined my design down to two components that would fit into the overall structure.
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A stable turntable
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A gearbox
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Using the same bearings on the turntable as the pump, I designed an easy to assemble, cheap turntable.
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The gearbox fastened to a stepper motor and used bevel gears to transmit the stepper's output to the turntable. ​
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This was a simple and effective solution that could be easily programmed.
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Final Throughts
This project was a lot of fun and I thoroughly enjoyed it. I was given numerous challenging tasks, each with its own set of explicit and implicit constraints and objectives, and the responsibility and autonomy to really grapple with them.
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My favorite moment is either seeing the pump work for the first time or the gradual process of seeing the overall design come together as the pump, turntable, gearbox... started to be extremely refined in their design.
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I'm extremely grateful for this opportunity and I felt I managed to hone my CAD skills, communication skills, and design practices so I could quickly, efficiently, and effectively create a design, modify that design as time goes on, and communicate the design and its function so it can be manufactured and assembled remotely.
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If given the chance to work on a similar project, I would love to apply the skills and techniques I've learned on this one. I would also emphasize the clear communication of the different objectives and their ranking. I felt I struggled somewhat in striking that perfect balance and think that spending the time to very explicitly lay those out would help.