A maker is a serial novice. I’ve built several robots. Each time I build a new robot, I learn something new–either a new skill, something new about electronics, or something new about programming.
Every project we do as makers has at least one new thing for us to learn. Great projects have more than one thing to learn, as well as using skills we already have.
We should embrace learning–that’s how we grow.
For my BB-8, I’m doing mixed materials. The dome and body are both Styrofoam, with additional materials added as necessary. One of the pieces I’ve added is an aluminum band around the bottom of the dome.
I managed to find a strip of aluminum at Ace Hardware that’s 1/16″ thick, 3/4″x48″. The band only needed to be 37″, so I cut it off with a rotary tool. I needed to get the correct bend, and I wasn’t sure that this particular strip of aluminum would bend okay. I measured and found that the rings on an orange Home Depot bucket are 37″, so I clamped the aluminum to one of the buckets.
This gave it a nice bend, but it didn’t stay at this curvature. Next, I glued it to the dome and clamped it in place while the glue dried.
I did some spot gluing at the very ends. The result came out nice. I guess I’m ready to start as an apprentice cooper!
3D printing is only one tool in making. Saying “I only do 3D printing” is like a carpenter saying “I only use a saw”. We use 3D printing for a variety of purposes:
The type of finishing needed varies depending on the purpose. For calibration, finishing would obscure the results. Internal parts might need only to have rafts and supports removed, or possibly some sanding or filing for fit. Visible parts or complete objects should be finished to an appropriate look.
As object-oriented programmers (or procedural), we have a tendency to write a lot of code with barely any functions. It’s better to adopt a mindset that functions are cheap. The only time this isn’t true is when you measure the speed of the code and find that functions are slow–typically because you’re calling them millions of times. Other than that, we should be using functions much more than we currently are.
The condition of an if, while, or for is a perfect place to use functions if the condition is complicate. Something like a == b is fine, but a condition like a == b || (c != d && e == f) could be pulled out into a separate function.
The body of an if, while, or for is another good place to pull code out into a separate function.
Using functions gives us an opportunity to name a condition or a computation. This helps make the code more readable. For example:
if (condition == CONDITION1 || condition == CONDITION2) { }
or
if (isErrorCondition(condition)) { }
Similarly:
if (objectDetected()) {
motorLeft(BACK);
motorRight(BACK);
wait(100);
motorLeft(STOP);
motorRight(FORWARD);
wait(100);
motorLeft(FORWARD);
}
or
if (objectDetected()) {
robotAvoidObject();
}
I’m building a BB-8. My BB-8 is a mixture of Styrofoam, metal, and 3D printed parts.
Here are a couple of the 3D printed parts:
These pieces printed pretty much the way they’re sitting. On my printer, this left ridges going around parallel to the circles. I finished these pieces by sanding. So much sanding. I spent several hours sanding each piece. I used 220 grit sandpaper. Because these pieces aren’t going to be handled much (they’re going to be attached to BB-8’s dome), I only sanded them until they felt smooth to my fingers. For a different project, I might have continued on with different sandpapers to smooth them out even more. I sanded perpendicular to the ridges (e.g. up and down).
I used standard acrylic paint (black and gray mixed) and painted each one a couple of times, mostly to get the right color. This gives a really good look. I adjusted the colors in the image slightly to bring out the pieces more. They look really good in person.
These pieces are supposed to be some kind of metal or plastic, so I stopped with the painting. I’ll do some weathering on the dome when I’ve finished painting and assembly.
If these pieces had been intended to simulate wood or stone, then I would have textured the surface. For wood, you can simulate grain by cutting lines with an X-acto knife (one direction), and doing some light sanding with a 50 or 100 grit sandpaper, then washing with a dark color. For stone, you can rough the surface up even more with sandpaper, depending on what look or feel you’re going for.
I printed out a Star Wars comlink. It came in three pieces: a microphone, a grip, and an endcap. With the initial print, neither the microphone nor the endcap fit the grip. The inside diameters were too small. This may be an artifact of either the printer or the slicing software.
I used netfabb to resize the microphone and cap to be 2mm larger. They fit the grip, but then the outside diameter was larger than the grip, so it doesn’t look right.
I still had the original microphone and cap, so I edited the grip model in Tinkercad using a circular ring, which I turned into a hole a scaled to just remove the outer portion of the connecting rings on the grip. Then I reprinted the grip, and everything fits and is the right size now. I painted the original–I still need to sand down the new one and paint it.
I received a Mod-t 3D printer from New Matter (after a year and a half of waiting, of course it arrived the week I was away on vacation).
The packaging is impressive.
The box itself has instructions for how to unbox the printer:
The instructions were simple to follow and resulted in this:
To set up the printer, you connect it to either a Windows computer or a Mac and download some software. The software sets up the printer’s firmware and helps it connect to wi-fi. Note that you need to be using WPA2. Our router was using WEP, so I had to upgrade it (and enter in new passwords for all of our wireless devices). After changing the router, I tried to connect the printer three times and got a “Failed to connect” message each time, and the printer status said it was disconnected. After the third time, I hit the Refresh button, and the printer was suddenly connected.
Once the printer was connected to wi-fi, the software wanted to print a test print. The test print is nice–it’s a 3D version of the New Matter logo. The print took a couple of minutes. To remove a print, you take off the build plate, which is a plastic plate that sits on top of the build platform. You can bend and twist the build plate, and the print will pop off. There’s a video at New Matter showing how to remove a print.
Next, I printed two copies of the Maker Faire Robot, which is a robot mascot from the Make 3D printer tests from 2014. The first print came out fine. On the second print, the robot’s arm was forward, like it was shaking hands, and the supports were rotated forward as well. I’m not sure what happened.
The next thing I printed was a space-filling (CPK) model of water. It came out beautifully–essential perfect for a 3D model, which means there are small ridges from the layers, but it is smooth and even. I really like the water molecule print. It came out well, and with the default 25% fill it has a good weight to it. This is going to be a nice print to finish (smooth and paint). I will post a final picture when it’s done.
When working on another print, the Mod-t had a calibration error and ended up melting a hole in the build plate. I talked to New Matter customer support, and they were very helpful. They’re sending us a new build plate, and on their suggestion, I sanded out the edge of the hole so it was even with the rest of the build plate and put blue painter’s tape over the hole. It’s working fine. If you’re new to 3D printing, it’s pretty common to put blue painter’s tape on build plates (depending on your 3D printer).
I’ve had one build fail because of a broken filament, and a second print fail because the filament got tangled and failed to feed correctly. That second one was my error–I didn’t feed the filament through the hole in the spool after it broke, so it managed to get free of the spool.
The firmware on the machine is still early–it’s version 0.5.0. New Matter is doing regular updates, and each update improves it.
I’m impressed with the machine–it’s quiet, reliable, and produces nice prints. It has a smaller build volume (6″ x 4″ x 5″ or 150mm x 100mm x 125mm), but I think it’s a good starter machine.
There are different types of software you can use to design 3D models for printing.
CAD software is good for building useful objects. It is based on building with solid 3D shapes and 3D holes (which are the same as the solid shapes).
Another way of creating 3D models is by using sculpting software. This type of software is similar to using clay. You can push the starting object in different directions to create a 3D model.
Photo reconstruction software works by taking a series of pictures of a real object and building a 3D model from the pictures. To get good results, you need at least one set of pictures from all angles around the object (maybe 10-20, depending on the software and the object), and then another pass from slightly above, angled down (maybe another 6-10 pictures).
After creating a model, sometimes there are problems with printing it directly. In those cases, you need software so you can go and clean it up (remove extraneous bits, close holes, make a flat base, etc.)
There are commercial services which will take your Minecraft world, extract your model, and 3D print it.
For all finishing techniques, please be careful and follow the appropriate safety precautions.
Acetone doesn’t work to smooth PLA. However, several people are experimenting with vapor smoothing using different materials (such as MEK substitute) and different techniques.
Sanding works, but it takes longer than for ABS. Basically, start with rougher sandpaper and work to finer, working over the material in small circles. Here’s a good example of sanding. Another specific example, going from 220 grit sandpaper to 600 grit wet sandpaper to #0000 steel wool.
You can try sand-blasting PLA prints. It definitely results in a unique look.
If you need to join two PLA pieces together, then friction welding may be what you’re looking for.