Tag Archives: 3D printing

3D printing fixed it


Ok, so the big promise of 3D printing is that I can get whetever item I need at any moment, in whatever shape I desire, which would be very handy for repairs and replacements. As anyone dealing with 3D printing can attest, the truth is that it is not always that easy.

Usually making replacement parts is either too time consuming and tedious, too difficult (in particular getting correct measurements of complex shapes and turning them into 3D models), or the part has some technical requirements that 3D printing cannot fullfil (e.g. heat resistance, strength, weight, etc). I know, today you can 3D print almost any material in almost any configuration. Just not at home, and just not at a reasonable cost.

But every now and then, something in our household breaks or gets lost where it’s almost trivial to replace it with a 3d printed part. One such thing was a clasp. Here it is:


It’s  a very simple interlocking clasp which works nicely. The original was made from metal and curved, so it looked more elegant, but replicating the original shape would have taken quite some time. So I went for a simple square shape. Here is the clasp unlocking:



I didn’t want to cut and resew the straps, so I left small gaps in the clasp, threaded the straps through the gaps and then sealed them with extra PLA directly from the hotend.


Here are the STL files: buckle05_femal.stl, buckle05_male.stl

Another very useful replacement part was this lamp holder:



It’s not the most beautiful accessory in the world, but it helped me revive one of these old office-style lever lamps. We had lost the original base a long time ago, and the new one simply attaches to the edge of my desk. Looks hacky and makeshift, but works nicely.

Here is the STL: lampholder_02.stl


3D printed key knob


When buying a new lock for your front door, smart people consider buying a lock with a turning knob on the inside, like this:


Photo by user BlastOButter42 on Wikipedia

It allows you to lock – not just close – your front door with a turn of the knob. Well, I didn’t, and thus I ended up with a lock where I had to put my key in whenever I wanted to lock my door.

Well, it’s never too late to fix something like this. The solution is simple: Just print a knob around a spare key. And I did. This is what it looks like:



I went with a square shape, as it’s actually easier to turn than a round one. The way I did it, is I created a rounded cube in Blender, then removed an outline of my key from the inside. I generated the gcode file, then separated it into two files – one containing the lower half, and the other containing the upper half. I printed the first file:


Then I inserted the key:


And continued printing the second half (with absolute z coordinates, the printer starts off right where it stopped before; you just have to be sure that the head is first raised to the appropriate height before moving along x and y; otherwise it might crash into the already printed part).

Here is the STL file (which obviously doesn’t work for keys of a different shape):



3D printed loom thread separator


My daughter is the proud owner of a loom. Recently her interest in the loom was rekindled by a school project, and as we wanted to start working with the loom again, we noticed that one part was missing. A wooden bar with slits which keeps the individual threads nicely separated, so that the shuttle can go above every second one, and below every other second one. This part certainly has a nice and professional name among those skilled in the trade, but I don’t have a clue what’s it called.

Anyway, since it was nowhere to be found and an extensive search of house and garden didn’t turn up anything (as expected), I took it upon me to print one. The model was quickly done in Blender, as it is just a bar with regularly spaced slits.

Printing took about 4 hrs, but the result was quite nice (in bright orange PLA):

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This week on Thingiverse


Here is a run-down of a few nice things I found on Thingiverse, ready for 3D printing. Clicking on the images will take you directly to the Thingiverse object. Let’s start with some transportation options. This nice rocket, by Gabor Vecsei, has that nice quirky vintage cartoon look:



And here is a nice model of the Edge 450 – the airplane used in the Red Bull air races – by mitchr:



And if you are more of a nautical person, here is a beautiful ship, by Grant Edwards:



3P3D published a model of a Chicago fire hydrant, created via photogrammetry. Photogrammetry is a process where you take an (ideally large) set of photos of an object, from different angles, and use software to deduce the original 3D contour. For those of you who have already tried it, you know how tedious and difficult it can be to get the result right. The hydrant turned out very nice, I would say.



Makers Empire, who are creating 3D printing software, have published this spider. I like how they balanced the naturalistic model with rounded, slightly abstracted shapes. Very nice use of 3D primitives.



And Ashwin Mandal created this beautiful model of the Sidney opera house.



Finally, something useful: Paulo Leandro dos Santos made a hard disk adapter from 3.5″ to 5.25″. These can be picked up very cheap in computer stores, but if you are in a hurry, it might actually be easier to print one.


3D printed airplane miniature


This was an experiment: I wanted to see how well Shapeway’s stainless steel prints turn out, especially for tiny details. For a test, I picked a model of the Lockheed Model 10 Electra – the airplane Amelia Earheart flew on her last flight.

I will be showing some paper airplane models at the Aero Expo starting on Wednesday, April 14, and I thought it would be nice to bring along a 3D printed steel model as well.

I had made a paper model of a similar Lockheed airplane before, and after tinkering with the schematics a little bit (more on this in a future tutorial), I had a 3D model that was fit for printing.

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Turns out, Shapeway managed to produce a very nice print. This is not plastic, but stainless steel. It’s bronze-infused, meaning it has an almost golden sheen to it.

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As far as I know, Shapeways uses a sintering process to print these, so there is no need for support material, and thus no visible attachment points. Being used to working with plastics, the weight of a stainless steel model feels great, too.

The details turned out very nice. I was concerned with the propeller blades, as they are very small and thin, but they printed nicely and don’t feel like they will break off easily.

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So, all in all I would consider this a success, except maybe for the price, which is not horrible, but not insignificant either – after all, this is a very small model (about 5cm long). Nevertheless, if you want to have one, too, you can order it from Shapeways. Mine took about one week for printing and shipping.




Bird Cage Egg


This is a 3d print I made last minute for Easter: A bird in an egg-shaped cage. The egg is just a little bit smaller than a real chicken egg. I like this one in particular because it is something that would be difficult to do with injection molding – at least in one piece and one step.


The kids like it very much. And it is a fast print – about 20 min.


You can find the model here. I have made two variants, one with a ring to hang it, the other without.



Also, since we are on the topic of Easter trinkets, here is a beautiful model by Mirice on Thingiverse which I printed: An origami bunny in plastic:

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3D printed cookie cutter bear



My wife found a very nice idea on the web for cookie bears holding almonds. Naturally, we wanted to have those bears, too. However, we didn’t have a bear-shaped cookie cutter. So I turned to Thingiverse and found this very nice cutter from user rozoom, which not only cuts out bears, but also makes dents for the eyes and nose.

I felt that the arms could be a bit longer, in order to be easier to wrap around the almond, so I created a slightly modified version. Works like a charm:

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And – as a bonus – here are a few other cookies we made:





And my personal favourite, little Lederhosen bear:


3D printed spider ring


You got to love 3D printing: The turnaround time from an idea to its execution is extremely short. Yesterday in the evening I had the idea for a spider ring (don’t ask – that’s the kind of ideas you get when you have small kids). Scavenged Thingiverse for a spider model, and found this very nice Creative Commons model.

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Created a ring in Blender, added a stud to the spider, to make it easy to glue it to the ring, and printed the whole thing (actually, in two steps, first the spider, then the ring). The whole process took about half an hour. Nice.

You can find and download the final model here.

3D printing complex objects without support


With the popular and affordable standard method of 3D printing, FDM (fused deposition modelling, a fancy way of saying that the object is created by squirting a string of liquified plastic layer by layer onto a support), one problem is that overhangs are difficult to print. Anytime something protrudes horizontally from a model, the printer literally needs to print into thin air.

The obvious solution is support: These are elements that are not part of the model, but are printed underneath overhangs so that they are stabilized. The support elements need to be cut off after printing, and often require quite some post processing, to make the finished part still look good.

I recently wanted to print the comet 67P (this model, to be precise). It’s not trivial to print, as the comet does not have any flat surface you could use as the base. I didn’t want to use support, as for this model it would have meant cleaning and filing a large part of the surface. So here is what I did instead:

I digitally cut the model into two halves, so that I would have two flat surfaces. I printed the first half. Then I printed a negative ‘mold’ for the first half, which was essentially a cube from which I had subtracted the comet shape with a boolean operation in Blender. I then put the first half upside down (with the flat surface at the top) into the mold, positioned the nozzle of my printer at exactly the right height on the z axis, and printed the second half right on top of the first half.

This is the negative “mold”:


This photo was taken after printing the complete object. The squiggly string draped across the mold is the brim for the second part, which obviously was printed partially into thin air (should have turned brim printing off). If you look closely, you can see that I put a short strip of double-sided sticky tape into the mold, to keep the first part fixed.

This is right in the middle of printing the seond half onto the first one:




And this is the printed comet:



The difficulty is to get the second print aligned with the first one. There is no software support for this as of now (would be a nice addition to Slic3r or Repetier Host). So what you have to do is align the second half and the mold perfectly on the x and y axis, slice them, print the first half, then the mold, keep it stuck exactly where it is on the support, and then print the second half.

For the second half, you have to manually move the nozzle on the z axis until it is right above the top level of the mold (too low, and it will crash into the mold, too high, and the second part will fail to print properly, or will at least have the first few layers come out very loose and unsightly). Then home it on the x and y axis,

Now you have to disable homing in the G code. For this, I had to delete the command “G28” (“homing on all axes”). Since Slic3r creates G code with absolute coordinates, we need to tell the printer to assume the current position on the z axis as zero. This is done with the command “G92 Z0”, which sets the current position on the z axis to zero. Here is a nice reference of G code commands.

Depending on your model, you may actually not need a whole mold – most often, a number of struts is enough. This is how I printed this business card holding hand:

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Started by printing one hald (the backside):

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Removed it from the support, then printed the struts:

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Note that the struts have indentations which perfectly fit the back of the hand:

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Then I positioned the nozzle, and started to print the second half (the front):

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Again, you an see the brim I forgot (once again!) to turn off. It felt strange, simply picking up the finished object instead of carefully detaching it from the support:

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The struts are created just like the mold. You create a couple of cubes, then subtract the object from them.


I have first split the hand into two halves, using a large cube and two boolean operations (“Add modifier, Boolean, Difference / Intersect”). Then I have created seven small cubes, and joined them. then subtracted the back half of the hand using once again “Difference”.


The result is not perfect – you can still see a seam where the second half starts – but depending on how well the nozzle was aligned on the z axis, the seam can be quite small. It’s definitely better than gluing to halves together, and depending on the model looks better than using support.