Testing The Limits Of The Cube

Yesterday I printed a sample Rook.cube file that came with the USB stick accompanying the Cube (see “The 3D Printing Revolution Has Begun“). I’m pretty sure the folks at 3D Systems must have tweaked the Rook  model and tested it thoroughly so that it prints flawlessly on the Cube. Also, from a 3D printabality perspective, its  important to note that the Rook sits flat on the base and has no over hangs. As such there is no need for rafts and supports. So basically there isn’t much that could go wrong with the model.

As engineers we are wired to design things keeping failure in mind, with the result that failure is always on the top of our minds. So me being me, I wanted to see the Cube fail. I searched through my archive of 3D models and found a file describing a pretty coarse hammer head shark. I picked that model since it had very thin features for the fins.

I scaled down the model so that it could fit the Cube build volume and that made the fins even thinner.

Common sense told me to orient the shark upright instead of sleeping on its side because that would give the fins a better chance of building properly. Also if I didn’t reorient the shark one fin would be printed over another. And since the “hammer head” of the shark would start printing first there would need to be supports up to the lower fin and supports between the lower and upper fin. With the fins themselves being so thin and not parallel to the XY plane, the Cube would need to build them in steps and not as a single hatch pattern. A recipe for disaster.

But then as a consumer its not my job to understand all these things. Say someone uploaded this file on Cubify.com and I downloaded it to print it on my Cube. I’m expected to simply import it into the Cube client and hit print, right? So that is precisely what I did.

Click to enlarge

This is what the Cube Client software looks like. Its very simple and easy to use. No menus, toolbar, command lines and complicated user interfaces. There is a 3D graphics area that represents the Cube platform. Above it icons for a wizard approach to 3D printing. You start by importing a .stl or a .creation file. Next you click the heal icon to automatically fill holes, stitch gaps, etc. Then you reorient the model if necessary. I didn’t do this. Next you click the “Center” icon to move all objects to the center of the print pad. If you have imported more than one model they are placed side by side. When you are ready to start printing you click the “Build” icon to let the software slice the model and generate the G code for the printer. If your computer is not physically connected to a Cube you will be asked to enter a .cube file name that you can save to a USB stick and insert into a Cube or send to someone who has a Cube. Otherwise you click the “Print” icon and the Cube will start printing. It’s as simple as that.

The Cube started by printing the raft, which is basically a rough platform that serves as the base for the supports.

It took two hours to build the shark. You can see the supports extending from the raft to the body of the shark.

After the Cube finishes printing you need hold the print pad under running water so that the magic glue gets dissolved and the 3D print comes off the print pad. The supports are loosely connected to the raft. So you can simply peel off the raft from the supports.

Normally you can simply peel or pinch off the supports from the 3D print. But I feared that I would rip off the fins of the shark as well while doing do. So I used my Victorinox key chain to carefully cut away the delicate parts. I also needed to sand the support stubs off the body of the shark but realized that I didn’t have any sand paper in the house. So I pinched one of my wife’s emery boards and got to work. 😉

As you can see the fins of the shark turned out just fine.

Let’s take a closer look at the fins.

The tech specs of the Cube state that its resolution is 0.25 mm (0.01 inches). This means the thinnest object that I can print will need to be just one layer thick that the thickness of that layer would be 0.25 mm. However, as you can see from the image above, the fins are not built using a single layer since they are inclined to the XY plane.

My micrometer tells me that the fin is 0.86 mm. I’m impressed.