Make a 3D Printed Japanese Cord Loom (Kumihimo)

I get very excited when I see my kids doing any kind of creative project. Whether it's sewing, painting, Minecraft world building, sand castle building - even cooking. I get even more exciting if that creative activity somehow triggers a 3D printing idea. 

Project Idea 

When I spotted my daughter making a Japanese Cord bracelet using a hand-made cardboard loom, the idea of 3D Printing one was obvious.

Apparently, this is called Kumihimo, officially. There was something magical about using a cardboard Kumihimo loom to make a bracelet - but the cardboard clearly wasn't holding up too well, and I thought we could 3D Model and then print a more durable and colorful loom really easily. We set out to do just that - a basic one to start, and then perhaps we'd customize later.

all parts before subtraction
and construction

Project  Goals

The model is mostly simple looking - but there were some objectives I had to influence the model. First, I didn't want it to just be a solid disk, that would take too long to print. Second, I wanted to make it rather thin, again to influence print speed, but also to make it easy to carry. Third, I wanted it to be rather small, so it could easily fit in a pocket. 

The basic requirements are a hole in the middle, through which the threads form the finished cord, and many slots around the outer rim to hold the thread or yarn material securely.

Making The 3D Model

The ultimate shape I had in mind was like a wagon wheel. It wasn't perfectly obvious how I would achieve that at first. I realized that it would be easier to put two donut shapes together with spokes, than it would be to cut out the sort of holes I envisioned around the "wheel". 

This would take 4 cylinders. First the outer cylinder which was only 2mm high and 35mm radius. That was the outer dimension - 70mm across (diameter). Second, a 6mm radius cyleinder, which I used to cut the hole in the center. Third, a 25mm radius cylinder to cut out most of the inner material in the large cylinder. and fourth, a 12mm radius cylinder to make the inner hub. 

I leave it to the reader (that's you) to figure out the series of subtractions which resulted in two basic donut shaped cylinders - one for the outer part and one for the inner part (hub). Then, using 8 simple 2mm high rectangles, I made the spokes to connect the two donut shaped cylinders. 

To make the slots in the outer rim of the model, I simply created a wedge which I could replicate 32 times around the center of the cylinders, which were now aligned at the center, and then subtract all those from the outer rim. The outer part of the wedge was 1.6mm wide to leave enough room for thicker yarn.

Get The Model

If you want to make these, you can try to replicate the process above (lots of challenge left to the reader) or simply download my model and print away. It is not a very long print given that it is less than 2mm tall. The last resort is to buy one - lots of them on the web if you search for japanese cord loom or Kumihimo - but that takes the fun out ;)

3D Printed Event Hashtag for Google IO 2016

Back in 2008, I attended my first Google IO event - a conference put on by Google to focus on tools and platforms for developers mostly (programmers).

Since those early days, the event has grown tremendously and is now the premiere forum for Google to introduce new, innovative products for everyone, with a deep focus on platforms like Android and Chrome and developers on those platforms.

But this isn't a post about Google IO. This is a post about a 3D Printed keychain I designed to celebrate Google IO 2016.

Model design

I admit - I didn't give much thought to this design. I simply wanted to have something to give out to my friends and others who show interest in 3D Printing (if you see me there, mention this post and I'll give you one if I have any left).

I just used the Google IO 2016 hashtag that I hope everyone decides to use - so not the long version #GoogleIO2016 - but rather the shortened #io16.

To make this model, I simply created the text, using Gill Sans font (which seemed to match the font on the GoogleIO site the closest) and then made a frame to hold all the parts easily. I actually referred back to my old post about 3D Printing text to help choose the font and to consider positive and negative (cutout) designs.

Making the model slightly more interesting

This is a rather boring model, I know. To add just a bit of interest, I decided to try rotating each letter/number a bit on the y-axis.

At about 15 degrees, this looked pretty good! I simply chopped off the bottom part (underside) of each letter/number after rotating to keep a flat base, and this became the preferred design for sure.

Got an event coming up? Got a Twitter hashtag you like? Make a 3D Printed keychain to show some love!

The Model

If you've really become a fan of GoogleIO, you might want to print some of these before the event on Wednesday this week (May 18-20, 2016).
Here is the model on Thingiverse :)

3D Printed Piggy Bank - a Journey in Problem Solving

This is a guest post from Bethany Jones, who currently teaches a 7th grade science elective called Engineering Design in Mason, Ohio. Bethany is the mother of two tiny humans and one very energetic dog. She is a tinkerer, lover of learning and recent 3D printing enthusiast.

“If at first you don’t succeed, call it version 1.0”

This has become my motto as I have leapt headfirst into the world of 3D printing with my 7th graders. One thing I have tried to share with my students is that it’s not all about the end product, but the journey you take along the way. There is often more learning that takes place through failing than if you get it right the first time around.  

Ever since our 3D printer arrived a month ago, I have been adamant that it not just be a toy, but an avenue for creation.  I am encouraging my students to try designing something on their own that has a purpose or that solves a problem. In an attempt to show them that I was in this crazy new adventure with them, (as well as wanting to test the print size limits of the printer) I decided to make a piggy bank.

I kid you not, about an hour into the print, a group of students are hovering over the printer watching in awe and one says, “how are you going to get the money out Mrs. Jones?” Face-palm. I had forgotten to put a hole in the bottom to get the money out! 

I told my kids that we’d just have to break it open. It ended up not mattering, as this version printed with a giant mystery hole in the back. But I quickly went back to the computer and edited my model to include a money-retrieval hole in the bottom. Great teachable moment about learning from your mistakes right? 

My students and I had fun analyzing the possible causes for the other print issues and we decided to try and make the walls thicker for more support and hopefully close the mysterious hole.

The second time around, I think something went awry with the printer as everything went well until the very end. The slot on the top printed crooked and the ears  were hanging on by a thread about halfway up. Since I couldn’t find any explanation for this, I printed the same model with no edits and it worked! Third time's the charm!

I am loving the iterative process of designing, printing, redesigning and reprinting until I get something right. It is a wonderful lesson that my students are learning as well. I am finding that in a world where they may have been afraid to fail before, they are energized by the possibility that they can analyze the problem and attempt to fix it! Beyond making something cool to look at, it is something to be proud of when you can create something on your computer screen and make it come to life as a tangible object to enjoy and share with others.

Piggy Bank: http://www.thingiverse.com/thing:1533937

*Addendum: Fast forward one day past writing this post and the poor perfect piggy version 3.0 took a flying leap off my desk and met his demise as a clean break ripped through his body, splitting him in twine. I almost cried real tears in front of my students. But looking on the bright side, as one must do to remain sane, we can now analyze broken piggy from the inside out.

4th Grader Science Fair Project: Stronger 3D Printing

Every year, my kids participate in our school district's science fair. This past year (March, 2016), my 4th grade daughter - working on her 5th science fair since Kindergarten - decided to use 3D printing as her target.

After some discussion with her 3D printing-crazed dad (ahem), she decided to test the strength of 3D Printing using different print orientations.

The problem she was working on in her project was how to print stronger 3D printed objects.

She witnessed an issue I had with some hooks I printed for my pegboard a while back, and she generally thought that was an area that could use some experimentation.
Yes - I helped lead her in this direction - no doubt about it.

Her hypothesis was that the vertical layers (layered upwards along the z-axis) were not as strong as the horizontal layers printed along the x- and y-axis. She has seen many failed prints (of mine!) and has gotten familiar with the difference between the upward layers of a print and the horizontal layers.

Two test links - one horizontal, one vertical

I'll leave all the details to the slide deck - embedded below - which she made and printed for her poster board for the 2016 Science Fair.

Replacing a Broken GoPro Drone part with 3D Printing

One of the most exciting things about 3D Printing is when you can use it to replace or fix something that breaks. Last time this happened, it was a clock which fell off the wall (no , I didn't knock it off the wall). This time, it was a small GoPro camera part.

Is it strange that I felt lucky when I had something break that gave me this opportunity again? Yes, it's strange. But at least I didn't break it intentionally ;)

The Problem (the broken thing)

I have an older model Drone (DJI Phantom 2) which has an older GoPro Hero 3+ connected to it using a Zenmuse gimbal on the underside of the aircraft. The GoPro is held to the gimbal with a hard plastic strap. That hard plastic strap broke.

As you can see in the image, the break was right at the part where the screw receptacle fits. As soon as I saw this, I knew that I could likely re-use the screw receptacles and fit them into a new 3D Printed plastic strap.

The Solution

I measured the inside spacing of the plastic strap and the thickness of the plastic in both dimensions. It was pretty simple to design a solution here.

First I created a rectangle block to represent the outer measurement (which was the inner measurement plus times the plastic strap thickness (times two for the width measurement since there are two sides to account for on that dimension but only one on the height). Then I created a similar block for the inside measurement to be used to SUBTRACT from the first block. That gave me the basic shape of the strap.

For the ends where the screw receptacles would go, I created a small 7mm x 7mm x 7mm block and then tweaked one edge to make a slightly angled side as you can see in the image. This was an almost exact replica of the original strap design. I duplicated that block for the other side.
I combined those parts so that I had one part for the whole strap.

Then I subtracted holes into the ends of the blocks where the screw receptacles would go. This was the only area where the model needed some precision - so it took a couple of tests to get it right. These holes were 2.1mm radius (4.2mm diameter) and 5.5mm deep.

The Model

Having the metal screw receptacles from the original part made this really easy. If I didn't have those, I might have just left a tiny hole in the plastic ends and hope the screws would hold on to the plastic, but I'm not confident that would work for very long.

If you plan on printing this part, be sure to get a hold of screw receptacles, or modify the model to have a different connection design.

You can find the GoPro Hero 3+ Gimbal Strap on my Thingiverse page.

Creeper Paper Clips (3D Printed)

After my daughter decided that the Heart-Shaped paperclips were a great gift for her friends for Valentines day, she realized that maybe the boys in the class should have a non-heart option.

We 3D printed a few of the Superbowl football paperclips as an option, but then came up with another idea - Creeper Clips! These have the face of the popular Minecraft (tm) creature called the Creeper. It's a simple pixelated creepy face with a paperclip base.

Design Approach

There was one interesting thing about this model that's worth sharing (besides the paperclip part which I've already over-used). To get the multi-color pixelated look, I created different thickness areas on the face of the model.

original with tiny 2.5mm pixel size

To do this, I simply made 2.5mm by 2.5mm square tiles that were 0.4mm thick, and randomly (but evenly) pasted them on the base model in depths of one or two tiles. That resulted in a model which had 3 depths, each of which lets through a different amount of light and therefore gives the appearance of multiple shades of green - giving the Creeper quite an authentic look!

Adjusting the Model

Turns out the tiny 2.5mm blocks don't print that well at speed or when printing many copies at the same time. I adjusted by doubling the size of the "pixels" to 5mm squares, and got a much better result without sacrificing the look of the final print.

different height pixels colored for visibility

I also created a larger size by simply scaling up, which also increased the size of the original pixels to 3.25mm, which also worked pretty well.

The final adjustment was to give more space between the inner shape and the clip. I started with 1.5mm, which tended to crease or cut the paper that it was clipped onto - so I increased it to 2.6mm for a much better result.

The Model

Here is the Creeper Clip paperclip model. Print a few dozen to give away to your Minecraft fan friends!

A Fancy 3D Printed Raspberry Pi Enclosure

The Raspberry Pi helps make learning about computers fun and accessible for many people - and has given the maker community a powerful computing platform in a tiny package. Actually - it's a small integrated circuit board without a  "package" - it doesn't always even come with a case.

When my daughter opened up her new Kano Raspberry Pi kit that she got as a gift, the "package" - the enclosure for the electronics - was one of the things that made the kit approachable and easy. Then, within hours of that insight, a good friend and blogger asked me if I had designed a Raspberry Pi enclosure for 3D Printing. My response was a fast "Not yet, but it's on the way".

Design Goals

I wanted my Raspberry Pi enclosure design to be more than just a box with holes for the wires. I wanted it to be good looking and inviting. I decided I would use the Raspberry Pi logo itself as the design for the box. Of course the box had to also be functional. The Pi had to fit in there easily and have a way to secure it and, of course, all the wire ports need to be accessible. Of course, like so many designs I do, I wanted it to be easily printable without supports - and I expected it to be two parts - a bottom to hold the board, and a fitted top, preferably one which held securely without screws.

Summary of This Design Journey

There were a few forks in this design road - so I figured I should just summarize them first so readers get a sense of how I ended up with the current design.

1) I started with the Raspberry Pi version 1 Model B (Two USB ports) - which has a specific size and layout of interface ports - implying layout of the holes in the sides of the case. Then I realized (after I got the general sizing all correct and printed) that most people, including my daughter, now have the version 2 design. (more info on Pi Models)

2) I moved to the Raspberry Pi 2 layout - using my daughter's Kano board as my basis for measurement. That got me designing in the right direction,  and I completed a box design with the right layout to fit that Pi 2 board. But it seemed boring.

3) I added a Raspberry Pi Logo-shaped bottom to the box, then created a custom top which was also in the shape and design of the Raspberry Pi logo. This looked really good - and had plenty of challenge creating the fitted top.

4) The shape of the Raspberry Pi logo was so nice, that I decided to make the whole box that shape - with adjustments to fit the board within it. I was finally satisfied after some adjustments to the top to make the Raspberry-ness really show, some strengthening of the walls, better fittings to make the top snap in place and addition of optional screw holes. 

This is where I am with my current design, but I'll fill in the details now for those who want to know more.

Basic Design Of The Box

I started with a box - figuring I would add the design elements as shapes on top and bottom of the box to give the whole package the appearance of the Raspberry Pi logo. So the focus to start was the alignment of the wire holes and screw holes and the general fit of the IC board.

After measuring the Pi board (approx 85mm x 56mm), I created a basic rectangle with those outer dimensions plus an additional 3mm extra space on all sides - that's 2mm walls with 1mm space on each side. The rectangle is now 91mm x 62mm - and I use the "Shell" command and define 2mm walls to get the hollowed out box where the Pi will fit.

Useful Trick for Early Design Testing

Drawing with all measurements

The placement of the seven (7!) port holes was critical to the success of the design, and no amount of measurement makes for a fool proof design or print. So, when I thought I had the whole bottom box design ready to go, I didn't want to print the whole thing until I was sure I hadn't messed something up. So, I came up with a method for testing a smaller version of my print to test that the placement of screw holes and wire port holes was correct.

It's worth mentioning that I created a Google Drawing which documented all the measurements in once place visually.

bottom portion only as a test

I only needed to test the bottom half inch of height - about 20% of the total printed object - to see if the mounting holes and wire port holes were positioned correctly. To isolate that portion of the object, I created a big rectangle which was slightly larger than the whole box and positioned it over a copy of the box,  specifically positioning it over the portion of the box I did NOT want to print.

Then I did a "Combine" / "Subtract" to remove the whole top of the copy of the box. That left me with the bottom portion. I printed that - which took about 45 minutes rather than the 3 hours the whole box would have taken, checked that it worked out, made adjustments and repeated. Two tries and it was done.

The subtraction shapes used to cut the wire ports and SD slot

Making Wire and Port Holes

I had to make 7 holes in the sides of this basic box. It seemed the best way to do this to allow for a few later adjustments would be to create and position 7 rectangles which would be used to subtract material from the box. Any later adjustments I made, even to the box itself, would allow me to re-subtract these same boxes, in their correct positions, from the adjusted box. This turned out to be an insightful move, as I made many box adjustments that otherwise would have been hard to maintain the holes if they were pre-made in the box itself. Once the boxes were positioned correctly, I did the "combine"/"subtract" command - with all 7 rectangles as the source - and voila, the box had 7 holes in it.

Screw mounts added where needed

Securing the Pi Board (screw holes)

To offer a way to secure the Pi board to the case seemed easy enough - since the Pi 1 has two screw holes and the Pi 2 has 4. But now that I had all my port and wire holes positioned, I realized that I needed to lift the board up a bit from the bottom of the case to give room for screws. This was luckily easier than it may have been, given the method I used to subtract the holes from the box. I just lifted all the subtraction shapes up 3mm and re-subtracted them from the box. I then placed small 3mm high rectangles (about 5mm square each) in the areas where the screw holes were needed and carefully measured as many angles as possible to get the holes positioned relative to the box sides and to each other. I used 1.25mm Radius cylinders to subtract holes from those shapes and aligned them to sit on the bottom of the box. Theses would also serve to hold the Pi board away from the bottom of the case with enough room for the bottom-mounted SD card and the small soldering nubs that stick out the bottom.

The Raspberry Shape - from Simple to Complex

To get the Raspberry Pi logo turned into a 3D object, I used an old trick that I've written about a couple of times. I pulled an image of the logo into Google Drawings and traced over it with the Polyline tool to create the Scalable Vector Graphics version that my 3D Modeling software can understand. With some foresight, I actually traced the outline of the raspberry separately from the inner designs of the raspberry, so that I would have some flexibility with the final objects.

I went through several iterations of using this design. As mentioned earlier, first I created a base with the outer shape - and this definitely made the plain old box look more interesting. Then I created the top with all the inner designs subtracted out. This was also a huge improvement to the plain old box.

Ultimately, after printing a very successful box shaped container with a top and bottom raspberry shape, I decided that the whole box should be raspberry shaped. The start was easy. I created the box with the raspberry outline extruded to 27mm, then hollowed out using the "Shell" tool in 123D Design. I then moved over the original box and started combining shapes - removing walls where they overlapped in areas which would be in the way of the Pi board, and combining walls where more support was needed.

Then, my original idea to save the subtraction shapes for the 7 side holes came in super handy. I moved them over, in their relative positions, to the raspberry shaped box, and subtracted them again. This worked wonderfully! The Pi Board screw holes were also moved in their original positions after adding another 1mm of height to the mounts to give the board more breathing room and the screw holes more depth.

Securing the Removable Box Top

Making the top snap into place in a way which did not require top screws was one of my design goals, and became the toughest part of this design. I experimented with a few methods before settling on opposing and offset half-round, 1mm deep rim pieces. I originally added too many of these sets of snap-together parts, and the fit was too tight - but with four of these sets, the fit was just right.

Even with the snap-togetherness of the top, I decided to add screw holes and mounts for people who want an ultra-secure enclosure. This was easy-ish - using tall 6x6mm towers on the inside of the box, and subtracting 2.5mm diameter screw holes 15mm deep into them, and through the top at the same time (to get perfect alignment).

The Final Model

There were lots of last minute adjustments, and overall, if I'm really honest about how much time I spent creating this model, I would estimate 10 hours of work not including printing time. I really obsessed over the design of the top, the combination of etched designs and full-through holes, which are functional in a case for something that might heat up like the Pi.

The final model is now available on PinShape. Please post pictures of your print on PinShape or on Twitter and include @MkrClub !

More Holiday 3D Printing - The Snowflake

The holidays are a great time for gift giving, and if you have a 3D Printer, nothing is more fun (exaggeration warning) than 3D Printing a gift for someone you love (or just like a little). My previous post which featured the Christmas Tree ornament/decoration was a simple way to start - and then I then posted the Snowman design which followed the same pattern. This new design - the Snowflake - has a slightly more interesting base design with circular symmetry and offered an opportunity to change to a more complex construction model too.

The first version of the design is the simple two-part construction, but the second version creates a much fuller final product by using three parts fit together at 60 degree angles rather than 90 degrees.

The first, too-complicated, design
but I will print this one too soon.

Design Goals

As in the previous holiday decoration designs, I was aiming here for simplicity and ease in printing as well as creating a mode symmetrical model that could eventually be constructed using 3 parts. The mostly flat parts are designed to easily fit together to form three-dimensional objects - something easy to hang on a tree or stand up on a shelf. Both Snowflake models in this post meet that objective.

Snowflake Design Overview

The snowflake took me a few tries to come up with a method that worked well. I tried drawing it with a sketch, but couldn't get it to look right. I knew I would need to use a duplicating method to get the symmetry no matter how I modeled it. I finally just used long rectangles overlapping with some shelled outlines of rectangles at the outer edges. 

This looked amazing - but was much bigger than I had hoped. I simplified that design starting from scratch, and used a simple cylinder in the middle around which the single crystal of the flake I designed could be repeated in a circular pattern. I knew I could use this basic design with both the 2-part and the 3-part final design, so I focused on getting this right first.

Snowflake Details

The tool in 123D Design to get that symmetrical circular pattern is the "Pattern" tool. Selecting "Circular Pattern" lets you repeat the single set of crystal objects in a circular pattern around the diameter of the center cylinder object - which is selected as the "Axis" of the pattern.

This tool was perfect for the job - and I could see how I could create many different designs with the same base set of objects. With the simpler and smaller crystal pattern, and repeating it 6-times around the center cylinder, I was able to get a simple, small design to try.

The final step was to create a slot in the center to allow two of these "flakes" to fit together at right angles. I simply duplicated the design, turned one 90 degrees and moved it half the distance off the other so that each would have a slot halfway down the middle. 

Note: I actually made that slot 0.3mm deeper than halfway to allow for a bit of printing imprecision, as always. The design also required that I had enough room between the crystal legs to allow the two parts to fit together.

The More Complex 3-Part Snowflake Design

I realized with this two-part design, that it could actually look much better with 3 parts fit together. I took some time to figure out how to actually accomplish this, but the math seemed straight forward. With three parts crossing at the center, there would be 6 sections, which means each would be separated by 60 degrees around the circle to create the full 360 degrees.

I accomplished this by creating center slots which, instead of cut perpendicular at 90 degrees, were cut (subtracted) at an angle of 60 degrees. The tricky part was that 3rd piece.

The first two (which are actually exactly the same) fit together nicely since they had slots cut halfway up the center on each - but the 3rd piece now needed a place to go. I achieved this by extending the center of the 3rd piece and cutting a slot which was the full length of the centers of the first two, and by cutting TWO 60 degree angles in that same slot. This allowed the 3rd part to fit over two other parts in the center.

There was one problem - at that shallower angle, the extended parts of each flake overlapped and didn't let the parts slide together. I had two options - either cut the slot through those parts too, or, make the height of the model shallower overall. I decided on the latter, reducing the height of each flake part from 2.0mm to 1.6mm - getting to that number only through experimenting until the flakes didn't overlap.

view of the center where 3 parts
come together

The image included here shows the center where the 3 parts come together, showing the angles a little more clearly - and the other image describes the differences between the parts (the first two are actually exactly the same). 

The Models

As always, here are links to the 3D Models:

Snowflake - 2-part - One part which should be printed twice to fit together (and stands on it's own or hangs from a tree quite nicely.

Snowflake - 3-part - Three parts (even though 2 of them are the same) included in this file to be printed at once. You can also hang each part as it's own decoration, or put them together to create a beautiful ornament or decoration for a shelf.