What makes Prusa i3 MK2 the best 3D printer?

It's a fully open source 3D printer out there.

Prusa i3 MK2 - 3D printer
Swapnil Bhartiya

I have been thinking about buying a 3D printer for a long time. However, I could never justify the $2000+ cost of a good quality printer, especially knowing that there would never be any practical use for it. I have played with 3D printers before at tech shows, but all they did was print the same stock object.

Then one of my friends bought a cheap 3D printer from Amazon and invited me over to have a look at it. He had printed cases for his Raspberry Pis, toys for his kids and even some Halloween decorations.

I started to get excited about the possibilities and I began my search for an open source 3D printer.

While my preference for open source is a matter of principle, I have a condition that it has to be better than its proprietary counterpart. Prusa i3 MK2 met that requirement.

A bit about Prusa

Prusa i3 is a fully open sourced fused deposition modeling printer developed by Josef Prusa from Czechia. The first Prusa i3 printer was released in 2010 and, being open source, it led to many clones. The popularity of Prusa i3 Mendel enabled Josef Prusa to set-up a company called Prusa Research. Now he has a team of engineers, designers, admins and support staff. (I tried two of the clones; instead of using best-of-breed hardware, they were cheap knock off implementations of the Prusa i3 concept.)

In 2016, Prusa released the Prusa i3 MK2 printer. The brain of the printer is the Rambo Mini board, which is powered by open source Arduino Mega 2560 and comes with drivers for four stepper motors. It runs on a modified version of Marlin firmware that’s open source.

There are two versions of MK2: a kit version that needs to be assembled for $699 and a fully assembled and tested printer for $899. The coolest thing about MK2 is that all the plastic parts are 3D printed, which means that you can print your own printer! If you order a pre-assembled printer, Prusa prints the parts, assembles and tests them, then ships them out. In the case of the kit, they just ship the parts. This means the kit version is shipped quicker than the pre-assembled version. 

I am an arch Linux user, so I don’t mind getting my hands dirty. I went ahead and ordered the kit, which arrived in a week because I splurged on expedited shipping.

The printer comes with two documents that will assist you in assembling it; there is  also an updated assembly guide online that is available in different languages. It took me around 4-5 hours to assemble the printer and I was ready for my first print.

The first experience

If you are new to 3D printing, imagine that you are trying to create an object out of thin air. Not literally, but you get the point; you are creating an object. There are a lot of variables and a lot of moving parts, which means a small flaw can ruin the whole print.

That’s where Prusa shines. The modifications that they made to the open source Marlin firmware automates tasks that can be a nightmare on other printers.

Prusa i3 is an open frame design, which allows for future upgrades and modifications. It uses a combination of rods and aluminum frames to build the printer. If you self-assembled the printer, the firmware calibrates the printer to ensure that the xy plane is perpendicular to the z plane. The firmware is smart enough to compensate for minor flaws.

After the successful XYZ calibration, the firmware fine-tunes the distance of the nozzle from the bed. This part is incredibly important as it sets the thickness of the layers.

The magic happens with two custom components: a heated bed and PINDA probe. Prusa custom made the heated bed, which uses fiberglass and resin, eliminating the need for a glass or aluminum plate. The unibody design incorporates a PCB for heating, and this design allows for evenly distributed heating across the bed. The bed also incorporated 9 zones that work with the PINDA probe that’s attached to the hot-end. The firmware runs two sets of tests that detect the position of the heated bed and its distance from the nozzle. Once that’s done, you have to run a vCalibration script that comes preloaded on the Micro SD Card that comes with the printer. That program allows you to refine the thickness of the print layer. Once these three steps are complete, you are ready to print.

(Calibrating these things manually on other 3D printers is a nightmare.)

In addition to this initial set-up, the firmware comes with many features that allow for better control during the print itself. You can pause and change the filament for a different color, adjust the height of the layers, increase or decrease temperature, and much more.

The electronic unit of the printer, which is a Rambo Mini board, comes with a USB port. I installed Octo Print on a Raspberry Pi 3 and plugged it into the printer. I also installed a Raspberry Pi camera. Now I can manage my printer wirelessly over the local network. I can keep an eye on the ongoing prints through the webcam and make changes accordingly.

Here are some of the objects that I 3D printed:

3D printing Swapnil Bhartiya

I have been using the printer since November and have been printing heavily on it. The only thing that I have broken so far is the thermistor. Prusa offers a limited time warranty, but instead of waiting for another week for the part to arrive from Europe,  I bought a replacement from MatterHacker for $8 that came the next day. I also ordered some spare parts such as a heated bed, PINDA probe and extruder in case something broke during a project.

One of the coolest things about this printer, compared to others on the market, is that due to open source hardware and software, I can buy parts from any hardware vendor and use it on my printer. The only custom parts are the PINDA probe and the heated bed that’s designed and sold by Prusa.

Some key reasons the Prusa i3 MK2 is the best 3D printer available:

  • It's affordable ($699 for the kit version; $899 for the pre-assembled version)
  • Fully open source hardware and software
  • Automatic everything
  • It's future-proof because you can upgrade to newer versions
  • Printable parts means total control over maintenance
  • High-quality prints
  • Open hardware means you can swap the hot end and nozzle with other standard units to get more precise prints

The print quality of the Prusa i3 MK2 is better than I've seen from some $3000 printers. Because I can swap the nozzle, I can even print tiny jewellery with it. I am amazed at the quality that you get with this printer.

If you are planning to get a 3D printer, I  suggest looking no further than Prusa i3 MK2.

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