Bailey Slow Feeder

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:

  • High strength
  • High density
  • High temperature
  • UV resistant
  • Food safe

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:

Bailey’s custom slow feeder bowl fit perfectly!

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:

Left: Top view, Right: Iso view. I cut the “B” into an arch so Bailey could reach all the food and made sure to fillet all sharp edges.

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:

Top: 3D print in various stages of completion. Bottom: Removal of support material. I was surprised at the great quality, high strength, and ease of support material for my first PETG print.

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.

Right: Top view of bowl post resin. Left-Top: Showing off shininess of the bowl. Left-Bottom: Water beading up on the print after washing. Not pictured: 48 hours of waiting, and the popsicle stick, old tofu container, and paintbrush all sacrificed to make this happen.

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…

Does she look most annoyed, confused, angry, or disappointed?

Quarantine Wall Decor

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.

A series of four string artworks we completed during the Great Coronatine of 2020

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.

Upper Right: Finished work; Everything else: various stages of planning/making

Baymax Cord Lock

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.

White? Check. Ovoid? Check. Fun? Check Check Check.

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.

Sculpt and boolean tools in Fusion 360 made designing and cutting the parts up for 3d printing a breeze!

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%.

Functional? Check.

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!

UPDATE: 7/25/2020:

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 think Blooper looks better than Baymax cause the strings are tentacles XD

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)_/¯.

Window Sill Shelf

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.

A simple, but effective design. I originally intended to print the shelf itself too, but I found a piece of wood that I’ll cut later to eliminate the use of this piece of cardboard, haha.

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:

https://www.thingiverse.com/thing:4462927

Stay safe and healthy!

#BlackLivesMatter Gear

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 openers.

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.

I modified an NIH-approved design to allow wearers to show solidarity with the movement.

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.

This touch-free door opener doubles as a stylus useful for hitting capacitive-touch buttons at self-checkouts. The strip of copper tape is the secret-sauce which allows this functionality.

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!

COVID: Endgame

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.

This is what ~50 lbs of empty filament spools looks like

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.

Quick update — now with earsavers!

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 earsavers (https://3dprint.nih.gov/discover/3dpx-013759) 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:

Left: 75x frames and 260x earsavers ready to be delivered this weekend
Right-Top: I’ve chewed through quite a bit of material… each spool is 2 kg >.<
Right-Bottom: 100x frames and 400x shields delivered last week

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!

N95 Respirator

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:

  1. The mask – this remained untouched from the original
  2. 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.
  3. 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.

Checking dimensions of the part against a photo

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.

Cross-sectioned view of the new cartridge system

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.

Printed cartridge with a real N95-rated filter

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.

Rubber window seals were used to create an air-tight fit

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!

Successful test of 1-way valve!

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 huge success.

An actual N95-rated respirator!

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.

Despite giving away my filter materials, not all is lost for me in terms of making pseudo n95 masks! The NIH actually approved of this design for clinical use: https://3dprint.nih.gov/discover/3dpx-013429 and both Keck (USC) and Cedars Sinai accept this alternative N95-esque design:  https://blog.crashspace.org/covid/

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 started with.

Hope everybody stays safe and healthy out there!

COVID19 Face Shields

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:

  1. 3D Printed Frame, ideally PETG, but PLA will work in a pinch
  2. Shield, made from transparent PET, PVC, or Acetate sheets
  3. Straps, optional for some designs
Prototypes

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.

First batch of face shields ready for delivery!

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.

Manufacturing

If you’d like to help, there’s a few ways you can pitch in:

  1. Find a local open source makers group and see if you can volunteer, especially if you have access to a 3D printer, laser cutter, or have sewing skills. There’s also lots of organizing and logistics support that honestly is just best done at the grassroots level. Here’s a roster of some local groups on Facebook:
    https://docs.google.com/spreadsheets/d/1JH5uL3WW6PwvwFRe4wqXkheK0-jcGYqaPmb9J3Dr6Ac/edit#gid=179139280
  2. Alternatively, if you want to donate to help me with material costs, I’d greatly appreciate it. Venmo @iampip is easy, and anything you can afford to give would be fantastic and will go directly to covering costs. For transparency, here’s what my outlays have been so far (not counting my N95 project, capital investments, and operational costs):
    https://docs.google.com/spreadsheets/d/17J_YbjUwo13Z-j28TjhQLMCv-tRQZK2QEVbqOquLPa4/edit?usp=sharing

    EDIT: Thanks for all the outpouring of support so far! Any excess donations I receive will be given to Good360. They have a similar mission centered around distributing goods where they need to go, and they have an excellent rating on Charity Navigator: https://www.charitynavigator.org/index.cfm?bay=search.summary&orgid=3752

Booklet Maker

TL;DR: I designed and printed a booklet maker for a friend.  

Instead of completing the Inktober challenge I spent the month of October designing and printing gifts for friends… and I spent November writing about them, haha. I posted about a Darth Vader dice tower here, an Ironman figurine here, and the third project I completed is this booklet maker.

My friend Will reached out for help solving a specific problem: he likes to staple papers into booklets, but needed a way to make them more easily and consistently. We went back and forth with some requirements (number of sheets at a time, staple placement, etc.), he drop shipped a stapler to me, and I started designing.

I began by modeling the classic Swingline 747 stapler from caliper measurements. I needed an accurate stapler model to ensure a good fit for whatever 3D printed part I would ultimately design. Capturing the draft of the side and determining the clearance available during stapler actuation was of paramount importance, so I created the stapler in two components and added movable mates.

Creating the stapler model in two components to allow for assembly mating features proved very useful in determining space available for designing

For this project there were advantages to taking a top-down design approach. In a new part model, I created a layout sketch to place the staplers per the desired specifications 6 inches apart on a line ¼ inch away from the left margin.

Taking a top-down design approach ensured the requirements were met from the beginning. All dimensions were driven from where the staples ultimately need to go.

With the staplers fixed in place, I focused my attention on the design of the main paper retention body. The trickiest part of the design was creating an attachment method that keeps a clear path for the stapler head to reach the crimp area.

After completing a test print to check the fit, I made a few adjustments to the paper backstop height, mirrored the body and connected the two halves with beam extrusions. Pictures speak louder than words, so here’s the build gallery:

Will tells me he’s very happy with the results, and I couldn’t be happier myself.

Action shot! It might take a bit of time for the gif to load