The Printer - Assembly and first Prints

Late July came, and with it, a 3D printer...some assembly required.

In this blog (there's a lot to cover) I'll touch upon the following topics.

• Building the Pursa i3 Mk2 kit, key points
• Calibration, calibration and more calibration
• First prints and expectations vs. reality
• What next

As I write, I've had two weeks of hands-on printing and lots of beginner anecdotes to share, but first; is it everything I hoped it would be? Yes, and more. It's almost become an obsession, and it lives in a two foot square corner of the kitchen. The term 3D printer doesn't do it justice, it's essentially a fabrication robot. A needy one at that.

It's also noisy. This was a big problem because I have a family, and some of them need to do things like sleep. When complex prints can take over a day and you only have a 12 hours print window it limits what you can do. While some 3D printers are said to be really quiet, this one is louder than an XBOX 360 attached to the Powerlifter from Aliens. That's a surprisingly good description of the sound it makes. I will cover how I ameliorated the noise problem in the last part of this blog entry.
BUT NOW.....

The Kit - It Arriveth!!!!

The backlog for the Prusa kit was seven weeks. It arrived on week six. News of early shipping hit the Facebook Prusa group along with news of new bigger offices.

I loved the obvious attention to quality control from the moment you open the box. Among the paperwork were hard copies of component tests.

Do they know I'm a test engineer? I LOVE this.

Every printer comes complete with "Jelly Delight"

The estimated build time is about 12 hours. This was accurate, taking three nights to complete following the well documented build manual which incorporated the latest updates and suggestions from previous builders. Impressive. The major problem I had was identifying part orientation in photographs. Quite a few people have problems with orientation, even when the manual states it in big letters. And I had done my research before hand, following the Facebook group clued me into many of these issues and what to look out for. Such as the "dot" stamped into the y-axis bed frame, this should face UP. The plastic Z axis end stops should have the flat part facing UP. The 3mm filament that acts as a cable support from the back of the extruder should curl UP.

Keep those three points in mind and it will save you a lot of time going back to fix it later. There follows a number of assembly photos covering the general build process.

Boxes - check

Y-Axis frame - take time getting this SQUARE now.

Y-Axis motor, endstop microswitch, belt, linear bearings, bed frame.

The "hot end", or extruder.
Filament goes into tube, down into heat block (with the wires) which melts it, squirts out the nozzle.

Extruder (X-Axis) bearings. Yes those are zip ties holding it together.

X-Axis end-stop microswitch.

Z-Axis stepper motor (one of two)

Frame and bed assembled.

Extruder assembly complete, cooling fans installed.

When the final assembly steps had been completed I didn't want to turn it on. The last time I built a kit with someone and did that it exploded. Well, it was a mini Tesla coil that generated lightning to play MIDI files and the resulting cascade failure in the primary power circuit vaporised a hole in the end of a protective fuse. But what a bang. 

No drama, it worked. The control panel LCD sprang to life and the machine guided me through the first calibration steps. 20 minutes later it was squirting hot plastic in a precise pattern over the print bed. It lives. However this would be a pattern I would see a lot of over the next few days...and weeks.

I did not count on the amount of time it would take to fine-tune this kit. It would be weeks of tinkering. But the biggest issue for the household would be the noise, but this turned out to be the easiest problem to solve.

The Backlog

My plans to build objects for flight simulation were been totally disrupted by a backlog of objects I found on the community site "Thingiverse". Many of these were "upgrades" to the Prusa i3 Mk2 to enhance quality of builds and reduce noise.

Printing objects from the SD card required physically moving a card between the printer and my PC. This rapidly gets old when you are experimenting. However there turned out to be a really easy and super fun solution, all it needed was a RaspberryPI Zero W. The "W" denotes it has Wi-Fi capability (important).

Remote controlled Printing and Monitoring - Over Wifi

Perhaps the easiest and quickest of upgrades. With a Raspberry PI Zero running a stock image file of "OctoPI". With the additional of a USB cable to the printer and 5v power supply, the 3D Printer can be operated over the internet via any web browser. Well, at least from your local network.

PiZero W - with optional camera

OctoPi is available from octopi.octoprint.org.

On powering up it self-configures and makes itself available on your local network via a web interface. From which you can upload GCODE printer files, control the printers steppers motors, temperatures. Best of all, if you have added a camera module, OctoPI can video stream your print (complete with MP4 video recordings in timelapse mode).

The next task was noise reduction.

The Prusa i3 Mk2 stands on four small legs with fabric pads. But much of the vibration is transmitted into the surface it sits on. There is also the fan noise but we'll come to that later.

I happen to have some EVA foam mats (exercise mats) for cosplay armor crafting, and one of these under the printer did dampen the sound however the printer sinks into the surface and improperly supported parts of the frame that shouldn't be. This needed a different solution and it came from a Facebook suggestion, use a paving slab.

A trip to B&Q later...

Cheap at half the price! Turned out to be the best four quid I spent that month.

We put the grey paving slab ON the mat. I cut spaces for IKEA Lack table legs.

A single grey Anthracite paving slab. It's quite dusty so I washed it, rubbed it down, washed again, let it dry then sealed it using a clear varnish (matt finish). Then placed it on top of the EVA foam. As I was building an enclosure for it to live in using IKEA Lack tables (these are five quid each) I cut space for the table legs. Turned out the slab was the perfect size to fit between the table legs.

The slab was the perfect platform, being of high mass it absorbs a lot of energy and didn't transmit much noise and movement. The foam padding great smooths out the bumps on the "top side" of the paving slab (since I'm resting the printer on the flat underside).

This provided a huge reduction in noise, but still had a way to go before I would be allowed to run the printer in the house overnight without it being a nuisance. And many large prints could take 20+ hours, so this had to work.

Next blog....

The enclosure and disaster strikes.