Ender 3 3D Printer

- February 26, 2020

I've previously experimented with trying to find suitable off-the-shelf enclosures to house my various controllers and sensors, and had come to the conclusion that the ideal scenario would be to build custom enclosures using a three-dimensional (3D) printer.

In last year's Black Friday sales, I was amazed to come across one of the most common 3D printers, the Creality Ender 3, and find out how cheap they were. Further, even the filament is reasonably priced.

So, after a few months of deliberation, I finally took the plunge, and purchased an Ender 3. You can see a photo of the constructed printer here.

And you can see the unboxing and constituent parts here:

The printer took around two to three hours to assemble, and I was guided by this useful video by 3D Printing Canada.

For those not familiar with 3D printing, the Ender 3 is a fused deposition modelling (FDM) printer. Basically it has three stepper motors which can position a heated extruding nozzle along each of the three axes of motion, relative to a bed on which the printed part is constructed. A fourth stepper motor pushes plastic filament through the nozzle. By following the right path, and pushing out melted plastic filament at the right time, the printer can create 3D shapes.

In the case of the Ender 3:

the z axis stepper motor rotates a screw drive that moves a gantry up and down
the y axis stepper motor actually moves the bed forward and back
the x axis stepper motor is attached to a drive belt which moves the print head along the gantry.

Another important part of the printing process is a piece of software known as a slicer. The slicer cleverly takes a 3D computer model, and creates the path that the extruding nozzle must follow. This includes constructing infill geometry so that the part does not need to be solid, thereby saving a lot of plastic! I downloaded and installed a slicer called Cura. Cura has settings for many popular printers, including the Ender 3.

It's also necessary to have some filament. There are multiple filament types; the most common filament for 3D printing is polylactic acid (PLA), however other commonly used filaments are ABS and PETG. After doing some reading I learned that PLA is derived from plant based materials, and generally emits fewer volatile organic compounds (VOCs), so I decided to start there, and purchased a couple of different types; some white Creality ST-PLA filament, and some blue Solutech PLA filament.

There are a few important set up steps after assembly, and again I used another useful video from 3D Printing Canada. These steps include feeding the filament into the extruder, and setting the bed level correctly. These two videos from Filament Friday and Nerys also helped me with bed levelling.

Now it was time to do some printing, so I started looking for models to start with.

The first model I printed was this calibration cube, which I found on thingiverse.

You can see the model in the slicing software Cura here:

And here is a preview of the slicer derived path for one vertical level, showing the infill. In this case I was using 20% cubic infill. In this image you can also see the skirt (the line around the object on surface of the bed) which Cura inserts by default. The skirt is useful for checking that the bed level is correct before the print starts, and it is possible to adjust the bed level on the fly if problems are occurring.

The Ender 3 comes with a removable bed surface, which I tend to remove after every print to help with detaching the print. Removing and replacing the bed surface can slightly alter the bed level, and so I find it is good to check the bed levelling as each print starts, and readjust if necessary, to ensure the print is adhering to the bed and the first layer looks okay. The skirt is very helpful for this.

Now, on with the first print.

Note that the cube is not actually oriented correctly after the print, and it should have been rotated so that the x and y axes were switched. This calibration print actually failed in that the dimensions along the x-axis of the printer (perpendicular to the Y face in this case) were too short. After a bit of investigation I realised this was because the x-axis stepper motor belt was too loose. You can see that this has also caused some imperfections on the Z face. After tightening the x-axis belt, and doing a second print, the dimensions were fine.

I then ran off a few more test prints.

Firstly this articulated butterfly from thingiverse. I am fascinated by the way it is possible to print connected articulated joints with a 3D printer. It opens up some really interesting possibilities.