Sep 19, 2015

Put a hole in it (Make your 3D Prints useful)

Many 3D Printed models that we make are pretty useless. Things like logos, name tags, even models of objects like buildings or vehicles or cartoon characters. I've found one little change I can make to most models to make them at least semi-useful.

Put a hole in it!

I've gotten into the habit of adding a loop or a hole in my models so that at least the object can be hung from a backpack, used as a zipper pull or put on a keychain. This is especially meaningful when teaching a beginner or a group of younger students, as it gives beginner 3D printing enthusiasts a way to show off their work and start a conversation about their new hobby ("Yo, what's that plastic bulldog hanging from your backpack?").

The first time I did this was with the first model I ever printed on my printer. I found a great simple set of Minecraft (tm) tools on Thingiverse. They were cool, but very useless. I simply added a keychain hole to the handle of each of the four tools and they definitely became more useful - or at least displayable.

How to do it

There are two simple methods to achieve this.

First, you can actually punch a hole in the model by subtracting a round circle from the main model with a cylinder. This is the best method for the flat models. I've found that about 4mm is the right total diameter to make it easy to get a key ring into the hole - but it also matters how much material you leave around the hole. It seems that 2-3mm is about right to get enough strength with not too much width to get a keyring around the material.
I try to pick a corner of the model for the hole to give more clearance for the keyring. Sometimes you can get lucky and the hole can become a natural part of the model - like in the Twitter bird name tag examples in the post about name tags.

TinkerCad Torus shapes
Second, you can add a small ring of plastic at the edge of your model - which is the most useful method for wide models which are not really flat enough to allow clearance for a keyring. The two shapes which work for this method are the torus - which is a rounded-edged ring, or a flat cylinder with its center removed. Again, you want to have approximately a 3-4mm hole and 2-3mm of material on all sides - so either of these shapes should have a total outside diameter of around 7-10mm depending on how much strength you need and how thick of a keyring you expect to use.

If you use the second method, remember to add the ring (torus or hollow cylinder) to a place which is conducive to successful printing - not floating out on the side of the model which will require supports or just fail to print right.

Doing this in TinkerCad or 123D

In TinkerCad - you're either using the "cylinder hole" object - aligning the hole object with the place you want the hole - or using a torus, which is offered in a few different ways in the Geometric Shapes category.

In Autodesk 123D Design - you've pretty much got the same options - using a Cylinder and subtracting that from the main object to punch the hole, or using a torus and adding it to the model in a position which will let it print successfully

Sometimes, the hole can be part of the model (birds eye)

Sep 14, 2015

3D Printed Pen Holder V2 - the "Peacock"

Just a few hours after using my first print of the "Porcupine" pen holder - I had a dozen new design ideas. One of them I had to immediately pursue, as I knew it would be more compact, take less time to print, and present the colored markers in a really cool display pattern.

One recommendation I always make is to save the individual elements of your 3D Models as you are making them BEFORE you combine them into a single object. That paid off for me here - as I went back to the elements used in the Porcupine model and was able to easily re-purpose them into the new Peacock design.

The basis of this design was to increase he density of pens which could be held into less space. To do that I interleaved the individual pen holder cylinders in two rows with each row facing inward toward the other so the pens criss-cross in a line. I also shortened the cylinders by about 10mm to make it print faster.

Another modification I made was to add personalization - with our @MkrClub twitter handle proudly embossed on the front of the model :)

Sharpie, of course, is a trademark of Sharpie corporation...

Sep 13, 2015

3D Printed Porcupine Pen Holder

I recently told a crowd of people that I feel a small adrenaline rush when I see arts and crafts supplies. Sounds crazy, unless you can relate to it, but even the sight of a large colorful set of Sharpies makes me want to create something. That got me thinking that while I have lots of those supplies, I rarely see them during a normal day - and I wanted to change that.

The Problem

I have a couple of dozen colorful Sharpie markers in my draw, or sometimes in a pile on my desk, since those sets almost always come in those annoying plastic covered cardboard packages with nothing useful for storage. It occurred to me that a rainbow of creative colors like that should be on display - always - to inspire creativity and simply look good. If you follow this blog, you know I even put Sharpies to good use when coloring 3D Printing projects.

The Design Idea

I decided on a whim to create a functional pen holder that would also look good on my desk by showing off the colors of the markers. The image in my mind was a "porcupine" or "sea urchin" pattern - where the colors of the pens could really be shown and the pens could be easily inserted and retrieved.

The 3D Model

I first created one individual holder without a base - just a hollow cylinder. Measuring my Sharpie markers, it seemed 12.5mm inside diameter would be enough to hold most pretty firmly - and 1.75mm walls would be strong enough. I created a cylinder with a 16mm outside diameter and hollowed it out so it had 12.5mm open inside. It was made 40mm tall to give plenty of support to pens which are about 140mm long.

Now I could replicate that one holder as many times as I wanted and put it on a base.
NOTE: I always tell people to actually 3D print smaller versions of your models before committing to large prints. This helps avoid the avoidable fail. In this case I SHOULD HAVE printed one of these cylinders to test it - but I didn't. It turned out fine - but I still stand by that approach of testing small parts of your model before committing to a 9 hour print (oops I just gave away how long this took to print).

Get the Porcupine Pen Holder Model File on my Page

Creating Symmetry

Trying to create symmetric geometry in my 3D Modeling app (Autodesk 123D Design) was a bit harder than I first expected. I wanted the holder to be stable - so it needed a wide base.  I also wanted the individual holders to be exposed (rather than be inset holes in a block) so that it looked porcupine-like even without any pens in it.  The base I envisioned would be a "Spherical Cap" - that is a cut off part of a sphere - with the pen holding cylinders sticking out in a perfectly geometric pattern.

Turns out there is no great way to position cylinders evenly spaced and correctly angled on the surface of a sphere. The method I came up used the SNAP tool which puts a face of one object perfectly on the face of another object. Even though that tool snaps to the same spot on a cylinder or sphere, I found I could snap one cylinder, then rotate the sphere and snap again - repeating that for the number of holders I wanted and being careful to rotate on the planes the same distance each time.

I actually used large cylinders as the base to get that rotate/snap pattern working on one plane at a time, and then rotating a duplicate of the whole thing on the z-axis - but after all that work, I realized I could have done it all on the sphere in the first place.

The Result

 This was a large model - probably my largest since the School Locker Pencil Cup I created several months ago (what is it with me and pen/pencil holders!). The estimated time to print was 8 hrs 34 min from Cura and it actually took 9 hrs 7 min to complete (overnight, of course) on my Lulzbot TAZ4.

The resulting pen holder works beautifully and achieved my vision for keeping lots of color and creativity within view and within reach! I've got lots of ideas on how to make this design even better.

Ideas For Version 2.0

Seeing this thing in action gave me a bunch of ideas for improvement or just interesting design alterations:

> Add a flat surface on the base for simple personalization (company name, twitter handle, etc).
> Flatten the top of all the cylinders on the same plane
> add a business card holder in front
> add a ring of straight standing holders around the perimeter
> make a square block which has the same pattern of pen holders inset into it.

Share your ideas please in the comments!

Sep 10, 2015

Hang Anything with the 3D Printed Figure-8 Rubber Band Hanger

I thought I was pretty smart when I 3D Printed some specialized pegboard holders to store my cans of hairspray (yes - hairspray) near my #3DPrinters. Well - it was pretty cool, but not so helpful to people without pegboard. So - after a few interactions on twitter with about the hairspray that comes with the Polar 3D printer, a different idea struck me. A new way to hang up cans of anything - in fact, a way to hang up practically anything at al on any hook at all. Different sized rubber-bands, smaller, perhaps custom-shaped figure-eights, and many other design tweaks could make this an even more versatile design - but I had to share this one as soon as it left the print-bed.


The design is almost too simple. A combination of two circles with one of them opened up just a bit (5mm to be exact) to allow for both connecting them together and for hanging. The resulting part looks like a figure-eight with an opening - and it takes two of them as a pair, along with a rubber band, to make the thing work.


I designed, printed and tested my first pair within 15 minutes of the idea.
THAT, my friends, is the power of 3D Printing. From idea to physical product test in 15 minutes. Even if this didn't work, I could at least start improving the design that soon after conceiving it. But in this case, this simple little product actually worked!

I created a quick video to show my first attempt at using the Figure-8 Rubber Band Hanger to hang up the hairspray that comes with the Polar3D printer.

3D Printing FTW!

The Model

Here's a link to the actual STL Model file on Pinshape...

Here's some other pictures showing how I can hang up other awkward things which don't have hanging holes or friendly shapes.

Sep 5, 2015

Fixed My Clock in No Time With 3D Printing

original part - broken
We've had a simple battery powered clock in the same spot on our wall for a decade. It matches the colors in the room and it works. Someone knocked into it the other day and it fell off the wall. The broken plastic parts on the floor told me it would not hang back up, as the plastic housing that held it on the wall and held the battery in place was permanently broken.

I smelled an opportunity for 3D printing!

The part that needed to be replaced was basically a hollow box with a protrusion that could be used to hang the whole clock on a nail. There was also a hole in the middle where the motor which turns the clock hands sticks through. Luckily, the housing which holds the guts of the clock gears was intact, except for a small part which held the battery contact.  I just needed the hanger box and had to make sure it was a tight enough fit to push the battery contact against the battery again.

I used my digital caliper to measure the inside of the box. I added the thickness I wanted for the walls to come up with the outside measurement of the box - which turned out to be 61mm square, with 2.5mm wall thickness.

In my 3D Modeling app (Autodesk 123D Design) I created the 61mm square box - 16mm high - and hollowed it out from one side. This is super easy in 123D using the Modify, Hollow tool.

Then I put a 16mm hole in the middle (measured from the broken part) by creating a 16mm diameter cylinder and subtracting it from the center of the box.

A small rectangle was added and connected to the top of the box, with a tapered lower edge (to avoid a complete overhang which would not print well). I also tapered the sides outward to give it more hanging strength and then punched a 5mm hole into it to be the hanger so the whole thing can be hung back up on the same nail from where it fell in the first place.

BAM! after only one measurement fail - which I caught super early in the print - I had the clock box printed, electronic guts back inside, and the clock was back on the wall in that same spot we've been expecting to see it for the past decade.

This model will also be added to my list of "useful things" that I've made with my 3D Printer - gaining some credibility with people who think I'm just fooling around making only useless plastic trinkets ;)

Tame Your Wires With The 3D Printed Wire Parking Lot

The mess of power and charging wires under and next to my desk is a disgrace. It's probably unsafe, and it's certainly ugly - but the main problem is, it takes me a few minutes to find the right wire each time I try to plug in any one of my many electronic devices. It's simply non-functional - and now, they are so tangled, there is hardly enough slack to even reach the top of my desk! ARGH!

The Idea

I was determined to design a simple multi-wire holder which let me easily keep the end of the wire close at hand, find the right wires fast and to avoid future tangles.

My idea was simple. I just wanted a "parking spot" for the end of each wire - most of which are micro-USB. I also have one iPad wire and one Mac wire. My goal was to create something fairly generic that would work for the ends of most any wire.

I wanted to be able to insert and remove each wire from it's parking spot easily, but have the wire held securely when it is parked.

The Design

My first iteration was simply a tapered hole in a shallow board with an entry slot through which the thin part of the wire could be inserted.

As I tested that design in a small version, I realized I could improve it by adding some separators between multiple spots which helped to make sure the ends of each wire did not touch each other.

The Print

I ended up with a 5-spot parking lot to which I added screw holes to secure this to a nearby side table. The result is incredibly functional and so far is solving my problem! I'm sure I need at least 5 more parking spots already, and I might add a system of labeling each wire too (since some have slightly different power profiles).

I'll definitely be adding this print to my answer to the oft-asked question "What have you printed that is actually useful?".

The Model

You can find this model on my Pinshape page.