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3D Printed Skull

I printed this skull back in 2019. The original file is this skull from Thingiverse. Now, it’s October 2020, so yeah, this took a while. I mean, I had it all printed long ago, and then I did an experiment where I covered one half of it with wood glue, and the other half with Smooth-On XTC-3D High Performance 3D Print Coating. I did this because I hate sanding prints (or wood, for that matter) and I wanted to test both methods of coating. For this application, I don’t know that it made much of a difference, but that might be due to the organic shape, and the fact that I primed and painted it afterwards…

Somewhere I’ve got photos of the coating process, but since they are nearly a year old now, I forgot to locate them. I do remember that the glue method took many more coats than the Smooth-On method, though of course glue is a much cheaper material…

You’ll notice the skull also looks a bit “weathered” and yeah, that was another test. I am not an “authentic movie prop maker” so I don’t know all those methods, and what I did was actually rub mud/moist dirt all over this thing and then let is sit for a long time. I eventually washed off a lot of the dirt because, well it was really dirty looking.

There are a few delicate parts of the print, and I’m pretty sure I broke off at least one piece and glued it back together. Again, since this is a pretty organic shape, no worries. And yes, it is pretty much life size.

I printed it in two pieces after slicing it in half, which means the surfaces touching the print bed are not visible as they are in the center of the skull, glue together. There’s a pretty bad seam that I never managed to get that sanded down quite right. I probably should have just taken a Dremel to it.

Overall I’m fairly pleased with how the skull turned out for a 3D printed object. It’s rare that I print “decorative” or “sculptural” prints since most of my prints are internal to some sort of enclosure with electronics inside.

Remember, the great thing about skulls is that we’ve all got one! (At least I hope.)

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Vinten Tripod Leg Lock

I was doing a video shoot with Ben Nelson for Brown Dog Gadgets last week and I noticed his Vinten tripod leg had an issue staying locked in place… Seems one of the leg lock pieces had broke in half. It seemed liked a perfect reason to fire up OpenSCAD and get the 3D printer spitting out a new part.

In the photo above you can see the new part in silver, and the two original parts on the other legs, in black.

It took two prints to get an acceptable fit. The first was a little too wide and wouldn’t quite fit in place. I tweaked the file just a bit and the second version worked well. I’ll walk through the process a bit below.

For an organic shape like this I usually start by putting it on a desktop scanner to get the profile. This one is curvy, and I’m not big on drawing curves in OpenSCAD, but I am big on scanning in an object and then tracing it in Inkscape. I did a few scans and even then I edited the image a bit to adjust the contrast.

I import the images into Inkscape, each layered directly on top of each other, then add another layer on top of that to do the drawing. I can then easily switch out the image below and compare things. For a symmetrical drawing like this I really just need to draw half of it, then I just dupe and flip to make the other half and combine them into one.

Once I have a vector file created I export that and then import it into an OpenSCAD file where I can extrude it changing it from a 2D shape to a 3D shape. Creating a solid object is the goal. Once I’ve got a solid object I can start knocking holes in it and adding angles by subtracting with various shapes. (The reddish parts are all subtractions or differences from the main piece.)

And yes, the above image does appear to be some sort of special forces TIE Fighter from the Star Wars universe.

Here’s our final piece, ready to be rendered, sliced, and printed. The original part had some pockets on the top and bottom, but since they were not required for functionality I left them out.

Ben installed it and briefly tested it and it seemed to work, though time will tell if it holds up under stress. (Also, this one is PLA so if he leaves the tripod in a hot car, it might soften and fail.) I’ll probably print a few more for him to keep in the tripod bag in case this one does fail in the field.

If you want to print one of these, you can grab the file from Vinten Tripod Leg Lock and have fun!

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SD Card Rescue Mission

I got a frantic message from my daughter Saturday morning. Seems she was shooting photos all day on Friday and when inserting the SD card from her camera into her computer (and another computer, and then her camera again) it would not mount. She did note that it was a little “damaged” on the corner…

The photo above shows some of the carnage that ensued. She brought the card to me, and I told her I’ve read that you can cut the card in half, remove the “chip” and insert it into a new card. I first cut in half a micro SD card adapter (since I have a lot of them) but that was no good. It’s internal design didn’t match up. No loss. Then I tried the card that came with my 3D printer, since it was only 4GB, and that did not work… I eventually told her that she might have to purchase an exact match so the chip would fit right…

She headed out to the store, found one, brought it to me, and five minutes later, Bob was your uncle. Meaning… it worked! I did warn her to just copy all files off it, and not to rely on it for the future. (She also bought a new SD card to replace it.) So now I had two of the “chips” from SD cards with no cases…

What else to do but 3D print replacements! I found a few models, and chose this Replacement SD Card Case to print. It printed pretty quickly, since it’s small and flat.

I ended up using a bit of super glue to hold the chip in place, and then adding electrical tape to it to shim it a bit so it would fit right into the SD card slot…

It sort of works… in some SD readers, but not all. That said, I’d recommend this fix for rescue, but I’m not sure I’d call the card reliable for everyday use. For instance, I’d prefer to not have it fail physically in my laptop, but in an external card reader I could tear apart if needed, I’ll use it. It seems to work fine in my Nikon camera, but not in my 3D printer, so… hit and miss.

If you go this route it might work, it might not… maybe there’s a better 3D model to use, I don’t know, and I super glued mine in place, which means I’ll wait until the next SD card failure.

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Fight COVID-19 with 3D Printing

I was talking to Caleb the other day and I mentioned how my favorite thing happening was the pairing of 3D printing nerds and people sewing masks collaborating because the sewers want bias tape makers and you can easily make them on a 3D printer. I swear I heard someone I know cry out “Finally! Having six different 3D printers will pay off!”

But seriously, Caleb wrote it up for MAKE, 3D Print This Simple Tool Now, To Help Local Sewers Make More Masks for Covid-19, and yes, it is a useful tool. I’ve probably given away over 50 of them in the last week.

Like others, I had started by printing visors for face shields, but I then jumped into the efforts we’re spearheading at Milwaukee Makerspace to produce a high volume of visors by milling HDPE on CNC machines. It’s faster, and the material choice is perfect for cleaning, disinfecting, and reuse, which may not be the case for 3D printed visors. (But, hey, if a 3D printer is all you’ve got, print away!)

So what is “bias tape” anyway? I will admit, I am not much of a maker when it comes to sewing, but these photos from a friend help illustrate how you use this thing. It’s for making the straps of a face mask that has ties on it. I guess elastic is running out, and some hospitals don’t want elastic, so you make your own bias tape with this thing.

Cut your fabric to size, pin it to your ironing board, run it through the device, and iron it down… then you sew it. (I think I got that right.) Also note, I did not design this. Someone mentioned they were printing this 4cm model so I just offered to help by printing more. I then cajoled a few local friends with 3D printers to also start printing them… we’ve made a lot of them now.

Last week when I was printing them like mad I was doing one at a time so I could grab it off the print bed, toss it in the box on my front porch and always have the box well stocked, as people were coming all day long to get them. Typically you might fill your print bed with 9 or 12 or 16 and hit print and come back 12 hours later, but I wanted these out fast, when there was demand, so one at a time made sense. (Plus, I’m working from home and a break every 35 minutes to walk to the printer helped me get my steps in!) I asked a friend to print some and he said “Yeah, I’ll have a bunch in 6 hours” but we had people wanting to pick one up ASAP, so…

While the full bed does make sense for overnight or if you’re away from the printer, I eventually switched to “one at a time sequence printing” where my printer will print 4, but not all at once, it will print one, then move to an empty part of the bed, print another, etc. This allows me to grab one off the bed as soon as it’s done, and the printer keeps going without me having to hit print again. This is great because even though I monitor the printer, I might be on a long call or doing something else where printing one at a time isn’t ideal.

The two groups I’ve been giving these to are The Masked Sewists for SE Wisconsin and Wisconsin Face Mask Warriors. Let me tell you, these sewing people have quite the maker network happening! They’ve got drop off points, tips & tricks for making, and they are sharing and encouraging each other. My favorite post was one that said “Finally! I can use all the fabric I bought for imaginary projects.” I think many makers can identify with that statement.

The other things I printed last week were these PAPR connector parts. I got a message last week from a guy who said they were working on this Open Source PAPR (Powered Air-Purifying Respirator) project, and wanted prints to make molds for resin casting the parts. I printed four sets so he could send them out to four teams to work on. I haven’t heard back on their progress yet but I wish them well.

Oh, one last story! I got a message on Facebook from a lady who wanted one of the bias tape makers and I said “Come get one! They are on my porch!” and she said “I’m in Florida, can you ship one?” So I asked where in Florida, and she said Orlando… so I got her in touch with my pals at MakerFX and they printed one for her. Maker Network Activated!

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Hangers

Back in 2018 while at Brinn Labs I was tasked with doing a mobile activity (the kind of mobiles you hang, not the kind that are British cell phones) and I came up with an idea based on the work of Man Ray, specifically his Obstruction sculpture.

man-ray-obstruction-instructions

hanger-svg

I designed a hanger that could be fabricated at a small size (approximately 5″ x 1.5″) and could hang more hangers from the ends. Man Ray’s version used full size hangers that had wire hooks and holes on each end of the wooden part which made it easy to link them all together. Mine was a bit different with a simpler one-piece design. I assume the hangers Man Ray used could swivel completely around, which is an added bonus my version would not have. (But there’s always more than one way to do it.)

Here’s a hanger laser cut from 3mm Baltic Birch plywood. The nice thing about 3mm Baltic Birch plywood is that it’s easy (for me) to find scrap that is around 1.5″ tall and use it for this, which meant I had no real material cost as I could essentially create these from scrap.

I should note that I originally tried using corrugated cardboard, which is even more abundant than 3mm Baltic Birch plywood. While it sort of worked, it depended a lot on exactly where the corrugation was after cutting. I abandoned the cardboard version after a few tests. (If I had made larger hangers I think the cardboard version could have worked fine.)

Because the hanger was a simple 2.5D object I also created a 3D printed version of the hanger… like many of the things I create I tend to come up with ways others could make them depending on the equipment they have available. If you don’t have a laser cutter but do have a 3D printer you can still easily create a bunch of these.

In the photo above you see four versions. Version 1 is the plain Baltic Birch version; Version 2 is a sanded and stained Baltic Birch version; Version 3 is a 3D printed version using grey PLA plastic; and Version 4 is laser cut from clear 3mm Acrylic. Again, multiple methods and materials to choose from.

Since I was working towards making a lot of hangers for an event I just cut them all quickly on the laser cutter and didn’t pay much attention to quality, so the backs of the wood hangers got a bit charred from the honeycomb bed. This is the part where it shouldn’t matter, but sometimes things bug you… so later I ended up designing a small jig to hold the hangers so I could sand them and make them look nice. I don’t know why I torture myself… I hate sanding.

Designing the jig involved creating a slightly larger version of the hanger and then differencing it from a small rectangular shape, then 3D printing it. It worked well to hold the hangers in place while sanding them, but in the end staining them a darker color was much easier. (Again, I really hate sanding.)

When I made the hangers I sort of envisioned it as a game where one or more people would try to build the hanging structure without it falling. Sort of a reverse Jenga perhaps, or maybe more like Barrel of Monkeys though I’ll admit I was completely wrong about how you play Barrel of Monkeys, and this video shows the correct way.

Overall I’m fairly pleased with how this projected turned out. Oh, I should note that the hexagonal tops on the hangers were mean to mimic the hexagonal logo of Brinn Labs. they could certainly have been more rounded or another sort of shape. Who knows? I may redesign these hangers in the future after a bit more prototyping. As I mentioned, this was a quick project and once I got a working hanger I just kicked out a bunch.

hanger-square8877

I hope I was able to create the “increasing confusion” that May Ray talked about in the instructions for Obstruction. It’s certainly a bit confusing when you are creating the structure, and at times I wished I had a helper to attach two hangers while I was attaching two hangers.

I’ll probably get around to releasing the files for this in case anyone else wants to do something with it.