TL;DR: I designed and printed a custom hook to store our oil screen on the back of our cabinet door to save some space.
Inspired by similar projects seen in various places online, I spent about an hour’s time measuring, designing, and printing a small custom hook to hang an oil screen on the back of a cabinet door.
Due to the simplicity of the part and the application, I decided to spend some time making deliberate choices to optimize performance. First was the design of the part itself. While I could have used a generic 3M command hook to achieve a similar effect, the tight custom fit of this hook prevents excessive movement and noise. Second, I decided to use PETG instead of PLA, a no-brainer for when strength is required. My last optimization was in the chosen print orientation. Despite requiring more support material, the orientation I used is actually ideal for the loading expected in this application. FDM printed parts are weakest parallel to the layer lines—that is, they are susceptible to delamination when loads pull the layers apart.
That’s pretty much all I’ve got–here’s to a year full of fun projects in 2021!
TL;DR: I printed a slow feeder bowl for Bailey out of food safe filament and coated it with an FDA-compliant food safe resin. It works, but I think she hates it and me for making it.
I’ve wanted to experiment with 3D prints out of PETG for a while, and finally found some time to do so during this long Thanksgiving weekend. PETG (polyethylene terephthalate glycol-modified) is a 3D-printable plastic with numerous advantageous properties:
The drawback is that it is a bit trickier than PLA (the most typical home 3D printed filament) to print. I invested an hour’s worth of time to adjust settings and complete two quick test prints before deciding I dialed my printer in enough to start a real project.
Our dog Bailey is a voraciously fast eater and I recently learned that various slow feeder bowls existed. However, most of the products on the market seem designed for larger dogs, and I wanted to make something that would fit in our existing holder. Spoiler image below:
The design of the bowl was straightforward. I measured the dimensions of our existing metal bowl, added another mm of thickness of the bowl for strength, added an extruded “B” in the middle to act as an obstacle, and finally made some cuts in the B to allow Bailey to access all the nooks and crannies. I took care to fillet any sharp edges away to ensure safety:
The quality of my first real PETG print exceeded my expectations… Based on troubles I’ve read about people having, I expected some blobs/zits or stringing issues, but surprisingly, I didn’t have any real problems at all. The ease of support material separation was shocking too–99.8+% of my support came off in a single piece, and the remaining two pieces were easily removed with pliers:
After the print was complete, I coated the bowl with this neat FDA 21 CFR 175.300 compliant resin I bought a while ago but hadn’t tried out before. The biggest pain point with the coating process was the 48-hour cure time. Luckily this was a long weekend, haha.
After washing the bowl with soap and water, I tested it out with Bailey by putting in a few training treats. She did not look very happy…
She eventually came around to eating, but clearly wasn’t happy:
I hope she doesn’t hate me forever because of this…
TL;DR: Tiff and I took advantage of a few lazy quarantine weekends to plan and create a few custom pieces of wall décor.
A few weeks ago, I posted photos previewing string art Tiff and I started working on. We planned a series of four. While she focused on making the most adorable one, three fell to me. For the background of pieces, we upcycled an old dress otherwise destined for Goodwill. This was my first string art project in about 7 years and actually found the act of stringing quite meditative and refreshing.
As a bonus art project, we also created a shattered mirror piece. I purchased “sliceable” adhesive-backed plastic mirrors for a different project but first wanted to experiment with how easily cut the parts were. I doodled a geometric hummingbird design while Tiff picked colors for and assembled the background from cardstock we had laying around. Cutting the mirror was harder than I expected, but got much better by the end.
I originally intended to add a simplified geometric rose to match the rest of the aesthetic, but it was difficult for my friends to figure out what it was. We went with a bundle of curvy cherry blossoms instead, and I think I dig the contrast in shape and colors.
TL;DR: A cord lock for Tiff’s hat broke… so I made a replacement shaped like Baymax since I had white material installed in my printer and I was too lazy to change it, haha.
Tiff got a great sun hat from a friend’s beach birthday party last year. I use it almost every day when walking Bailey. I noticed that the cord lock was starting to break, so I decided to make something useful while scratching my maker itch now that the need for PPE has declined.
Since I currently have black TPU (an elastic material not really suited for this application) installed in one printer, white PLA installed in my other, and a severe lazy streak, I needed to design something white and ovoid.
With proper source material in place, knocking out the design was straightforward for me. I decided to use the sculpting tools in Fusion 360. Sculpting is great for quickly making organic shapes that don’t require a lot of exact dimensions. Fusion makes it super easy to combine sculpted forms with parametrically defined features as well. I split Baymax’s body into two parts, one main body and a removable front plate to install the spring and legs.
Since the part was very small, I initially had some troubles with Cura deciding some areas (primarily the cut out for feet to retract into the body for cord installation) were so thin that I must not have wanted material there. I solved this problem by reshaping the Baymax body a bit and scaling the parts up by roughly 15%.
Overall, I’m pretty happy with the results… despite it looking slightly terrifying, IMO… like Baymax lost a fight. Maybe I should have gone with some sort of squid ¯\_(ツ)_/¯.
As always, hope everybody is staying safe and healthy!
Looking at the Baymax cord lock I made last week depressed me because it looks like his body is getting pierced by some sort of tentacled foe. I decided to replace it by designing a Blooper (the squid thing from Mario games), since it is also white, but looks natural with long arms:
I used all the same tools I used for Baymax to make Blooper, but it was much faster the second time around. While I like this cord lock looks better, but Tiff doesn’t like it because of all the legs, hahaha ¯\_(ツ)_/¯.
TL;DR: It gets hot in SoCal so I overengineered a shelf to hold a fan to
blow cool air into our bedroom at night.
Just a quick post this time—I decided to put my printer to work making
another functional print! SoCal is a desert, so it gets very hot during the
day, but cooler at night. A few days this past week were especially brutal. To
help circulate the air at night, we use a little Vornado fan, but its
effectiveness wanes when it doesn’t have access to cooler air.
I designed a very simple shelf comprised of brackets, a brace, and the shelf itself. I sized the brackets specifically for our bedroom windowsill. There is a very satisfying click during installation, but the shelf is very easily removable in case we need to close the window.
I didn’t end up printing the shelf part because I found a piece of spare wood which will work perfectly, and I installed a piece of cardboard until I find time to cut it. Although this specific design isn’t super generalizable, I decided to upload it to thingiverse anyway in case anybody is inspired to made minor modifications to fit their needs:
TL;DR: I believe #BlackLivesMatter. I still can’t say anything more
eloquently than what has been said by others elsewhere, so I’m going to chip
into the cause in my own way. If you’ve donated to a reputable social justice charity,
I’m more than happy to send you some 3D Printed #earsavers or touch-free door
Despite law enforcement agencies across the country telegraphing they don’t believe
so, black lives do matter. To help the cause in a small way, I designed a new
earsaver and a touch-free door opener/keypad stylus.
The earsaver is a modified version of the NIH-approved design found here: https://3dprint.nih.gov/discover/3dpx-013615. No critical outside dimensions were altered, and the part remains very flexible. Earsavers are very useful for anybody who needs to wear a mask (aka EVERYBODY WHO LEAVES THEIR HOME). You put this on the back of your head and hook your mask straps around it instead of around your ears. This takes the pressure off your ears and makes wearing the mask much more tolerable.
Creating the door opener/stylus was a bit more involved; I created the design from scratch, using a few existing designs as inspiration. The hook is useful for opening door handles without touching the surfaces. A strip of copper tape wrapped around the fist allows the stylus to function on capacitive touch screens, as long as you touch the bottom of the strip with your thumb. This is useful for pressing buttons at the self-checkout line in grocery stores.
If you’d like some of these doodads, I’m happy to send them to you free of
charge. Since I literally finalized the design at lunch today, I don’t have a huge
stockpile right now. For now, I’m going to prioritize those who have donated to
reputable social justice related charities, but I aim to eventually provide
these for anybody who wants them, so feel free to reach out!
TL;DR: Since the acute need for PPE has diminished, I am no longer producing parts on regular basis. However, I do have a reserve of face shields and earsavers remaining, and am more than happy to ramp up production if you or anybody you know need equipment.
Over the past 8 weeks, I personally manufactured about 1000 face shields and 1000 ear savers on my two 3D printers, delivering a quantity of about 880 of each to healthcare friends and friends of friends in places all over the country including: LA, SF, OC, Oakland, Tennessee, Oregon, South Carolina, Georgia, and New York. Furthermore, two local groups I work with have distributed over 75,000 and 22,000 face shields and other units of PPE, respectively.
However, it appears that more and more hospitals are getting their supply chains back in order, and the shortfalls do not seem as desperate as they were a few weeks ago.
I feel this was a huge accomplishment, and I could not have done it without the support of everybody who chipped in for expenses—it was incredibly generous of you. I plan to donate the remaining funds to the charity Good360 in a few weeks if the need remains low and seems unlikely to ramp up in the short-to-medium term.
I hope everybody has a wonderful Memorial Day Weekend, and stays as happy and healthy as possible. I sincerely hope enough of us remain vigilant and change our habits enough to ensure the gains and sacrifices we’ve made the past few weeks are not wasted. I pray that the worst of this situation is truly over for us. However, if there’s one silver lining to this, I know that if the need for more PPE arises again, we’ll be able to ramp back up much faster next time.
TL;DR: In addition to face shields, I’m now producing NIH-approved
earsavers. Let me know if you need some!
About two weeks ago, I upgraded my old cloggy 0.4mm nozzle to a great 0.8mm
nozzle courtesy of Micro Swiss (https://store.micro-swiss.com/).
Making this switch greatly increased my printing capacity—when you go from a
smaller nozzle to a larger one, the volume of material you can deposit
increases by r^2–you reduce both the travel count within each layer, and
increase the layer height at which you can print at. This leads to a huge boost
in printing speed, with the drawback of losing details. However, for what I’m
mass-producing right now, loss in detail is a very minor concern, so cutting my
print time nearly in half on one printer is well worth the trade off.
While I continue manufacturing and delivering NIH-approved face shields on
one printer, I’ve dedicated my other to the production of NIH-approved
for the next week or two. These popular devices are great for relieving
pressure off the ears of healthcare workers who need to wear surgical masks for
hours on end during their shifts. By the end of this week, I will have
delivered over 350 of them (including shipments to South Carolina, Tennessee,
Oregon, and NorCal!)
Here’s a snapshot of my life for the past few weeks:
Let me know if you or any of your healthcare worker friends need any face
shields or earsavers! I’m happy to ship them out.
Again, hope everybody stays safe and healthy out there!
TL;DR: I made a working respirator using a small stockpile of N95
replacement filters I have… However, since a local hospital has the appropriate
adapters and real respirators, for the greater good, it makes the most sense
for me to simply donate my materials.
Two weeks ago, I completed the design of, and successfully tested a
prototype N95 respirator. Before everything was sold out, I managed to buy a
small stockpile of about forty 3M 5N11 particulate filters, typically used for
industrial purposes. Unfortunately, I didn’t find any of the requisite adapters
nor compatible respirators.
Luckily, what I did find was this great project called S.A.F.E
(self-assembly filtration unit for emergencies) from the Medical University of
South Carolina (MUSC) (https://web.musc.edu/innovation/covid-19-innovation/safe-cartridge-system-and-masks)
to use as a starting point for my own design. In the original design, MUSC
recommends using part of a furnace HEPA filter as the filtering material
inserted in a replaceable cartridge system. What I believe was the true key to
their design, however, is the inclusion of a simple one-way valve. The valve
makes it easier to breathe out, prevents excessive CO2 buildup, and extends the
life of the filter, but it does not prevent the user from spreading COVID-19 if
they are already infected.
To speed up the printing process (and thereby the prototyping and
fit-checking stages), I broke the system into three main components:
The mask – this remained untouched from the original
The tube – This component was originally built into the
cartridge, and attaches the filter to the mask. The tube also houses the
one-way valve, which I thought was a particularly high-risk feature, so I
wanted to be able to test it separately.
The cartridge – I needed to replace the HEPA filter
design to fit 5N11 replacements.
Since the mask needed no modifications and changes to the tube were minor, I
was free to focus my energy on creating a cartridge to fit filter replacement
pads. To be honest, even this was a fairly straightforward design job… I took a
few measurements of my filter and made a simple enclosure, making sure that the
tube would fit into the back. One neat trick I employed to check my fit before
printing was that I took a photo of my pad and imported it into my design
software to ensure all my geometry looked correct.
While I originally intended the design to be a snap fit to make it easier to
swap out the 5N11, I decided that simply sealing everything in place with hot
glue, and turning the cartridge into a single-use item would be safer. It is
simply much harder to guarantee a seal if end users are the ones making changes.
The tube only took about half an hour to print, so I made that first to test
the valve. The S.A.F.E. design called for the use of heavier rubber for the
flap, but the only material I had available were thin inspection gloves. Luckily,
the design was robust as-is! However, since my membrane material was much thinner
and tended to curl, I paid extra special attention to ensure the curl direction
defaulted to the closed position. Next, I made the filter cartridge. Since I
had checked all my dimensions electronically before, the parts fit together
perfectly on my first try—yay! I hot glued a filter in place to make sure the
only path for air was through the filter pad itself.
Since the mask took hours to print, I made it overnight. Unfortunately,
sometime in the middle of the night, my nozzle clogged a bit and/or my extruder
skipped a few steps. This resulted in some underextruded and weak layers, which
caused the mask to break as I removed it from the print bed and cleaned up
support materials. However, since the breaks were clean, I was able to fix the
mask in a quick and dirty way by simply smothering the interface with hot glue.
I then attached some rubber material used for sealing windows to the inside of
the mask to ensure I could get a tight airtight seal on my face.
Assembling the mask was simply a matter of attaching the cartridge with tube
into the corresponding hole in the mask. I put the mask on and breathed in and
out to ensure the valve operated as intended. Then, I did a vacuum test—I covered
the filter with a sheet of plastic, and breathed in extra hard… and… success! I
was able to hold the plastic up, demonstrating no leaks in my mask!
Despite some initial success, I quickly realized there were some potential
issues with my mask design. First, the positioning of the filter is non-ideal
for healthcare workers. Although the filter is out of the way for the doctor,
it is facing a potentially exposed area where it is super easy for a patient’s
cough to cover the filter itself. Second, my design lacks any sort of exterior
grating to protect the filter. Regardless, I saw the two units I did make as a
As an engineer, I really love designing and making stuff. However, in this
situation, I realized that if any hospitals actually had the real adapters and
respirators to pair with my 5N11 filters, then the filters would be better
utilized as donated goods. I contacted a few hospitals in my area, and UCI said
they could accept them.
As an aside, now that I have two printers running, my output has tripled (my
2nd printer has a bigger build area than my first), and with bigger
nozzles coming in, I expect my output to increase again to *FOUR* times what I
TL;DR: I’ve been busy making supplies for COVID. You can help!
Throughout this lockdown, I’ve dedicated nearly all my spare time to helping
out where I can with COVID19 (not even really taking time to doodle! T_T). I
doubt I need to educate anybody on the crucial need for PPE in the US.
Accordingly, the two main projects I’ve undertaken are:
N95 respirator design
Face shield manufacturing
While there’s a bigger shortage of N95 masks and respirators, designing one
that actually works well is tricky, and it’s a topic for a future post. On the
other hand, there are plenty of easy to make open-source face shield designs
out there, and hospitals around the globe are accepting them. In conjunction
with other PPE, face shields keep healthcare workers safe by preventing
droplets from sneezes and coughs from reaching their faces.
The face shields are comprised of three main components:
3D Printed Frame, ideally PETG, but PLA will work in a
Shield, made from transparent PET, PVC, or Acetate
Straps, optional for some designs
After searching around for a while, I’ve become heavily involved in a dedicated group of local Orange County makers. While we’ve just really started ramping up in the past week, we have collectively already delivered over 318 face shields to hospitals in Santa Ana, Long Beach, Norwalk, and Riverside, and we have orders pending from 24 facilities for over 1700 shields… This includes repeat commitments of 780 units per week.
Personally, I’ve delivered a small batch of initial units to local
healthcare friends on the front lines, while I’m working out the kinks in the
manufacturing process. This week, I’m on the hook to deliver 55 face shields to
local clinics. I’ve just published improvements to two popular designs to thingiverse.
The improvements allow parts to be printed in stacks, giving makers more
downtime between needing to fuss with printers, and allows for more fully
utilized overnight printing. I fully admit that this idea was shamelessly
stolen from other members of the OC makers group:
With my current capacity, I’m able to do between 10 and 15 frames per day.
However, to keep up with the increasing demand, I ordered another printer, so
hopefully I’ll be able to boost my production to nearly frames 30 daily this
week. Tiff has pitched in to help with hole punching shields, and she’s been a
trooper in allowing this to take over tons of my time (and a lot of the space
in the living room), so I wanted to give her a special shout out <3.
If you’d like to help, there’s a few ways you can pitch in: