Author Topic: The Original Prusa I3 Mk3  (Read 3056 times)


  • Member
  • ****
  • t
  • Posts: 47
The Original Prusa I3 Mk3
« on: November 24, 2018, 12:02:51 PM »
Hello Rebels!

Intro aka The why

I gave in!
After all my more or less custom builds: clunky Mendel, the Hugo based Bumblebee, Acryl, The unnamed delta, The Foosa, The very secret secret one.... I've managed to get frustrated enough by recurring printing issues, cheap parts, experiments, experimental firmware and ended up having a semi functional Acryl which still need a lot of the aging parts replaced and probably a new hotend too.

So I gave in and ordered an "Original Prusa I3 Mk3" printer kit. It's somewhere in Budapest at this time on it's way to Romania where DHL estimates it will  be delivered by Wednesday.
Considering the kit price of almost 800 Euro I cannot call it cheap compared to the Chinese kits you can land for around 200 $ on Gearbest or AliExpress   you might ask why this and not an A8 or some other cheaper kit.

I'll try to answer:
- this machine is made by the same man that 10 years ago was helping starting a revolution which today makes it possible to have a machine that prints actual parts - mr. Joseph Prusa - the price I pay is my contribution back
- I did my home work :) It's one of the best rated printers of 2017 and 2018
- It packs a bunch of sensors and features most notably 
   - auto calibration on all axes
   - auto mesh bed leveling calibration
   - no home switches!
   - magnetic hotbed with pei coated steel sheet - print is done you take the sheet and flex it - print just pops
   - original e3d hotend
   - original bondtech extruder parts
   - filament sensor - well I hear there are issues there but well
  - Prusa maintained Slic3r and Marlin flavor
   - 24v system out of the box

This shall be my Bosh grinder, my Proxxon router, my Makita, my machine to go to and print stuff when I want to print stuff ... whatever stuff that is.
I'm done with building printers ... well after I get this one going, and I'll try to focus on other things I have not touched in ages. Robots ? Maybe..  :)

I will try to keep a log of the build in this post with my own thought on the build added.

Part 0 - Ordered what now?
OK if you decide to get a kit from there are a few things you should know:
1. Everything plastic is printed in PETG on their own printer farm so if they have lots of orders in queue well you might have to wait - my order was placed on Friday 16th November, it stayed in "Payment accepted" state until Wednesday 21st  when it  switched to "Shipping soon" and finally shipped Thursday on 22. Depending on which carrier you select, DHL was the cheapest for me, and where you live it will take a while for it to ship, surprisingly Czechia to Romania  takes 7 days :/
2. The above was stated for a kit that was listed in stock with 3 days lead time that might change.
3. There is a table on the site which details rough shipping times but best is to just ask them on chat.

My take: well it probably depends on your luck and how busy the factory is  :)

Well this is all I have for now, Wednesday I should receive it ! Yey!

Part 1 - It's here! Assembly!  - currently updating ... stay tuned

DHL ringed my bell a day earlier (yey!) so this is waht I've got:
*DSC_0656.jpg (62.42 kB . 1024x576 - viewed 209 times)

And after the black stuff:
*DSC_0657.jpg (42.51 kB . 1024x576 - viewed 205 times)

Manuals and Haribos:
*DSC_0658.jpg (76.64 kB . 1024x576 - viewed 201 times)
Lots of little boxes:
*DSC_0659.jpg (77.37 kB . 1024x576 - viewed 207 times)
*DSC_0660.jpg (60.94 kB . 1024x576 - viewed 207 times)
Y axis
*DSC_0661.jpg (57.31 kB . 1024x576 - viewed 192 times)
*DSC_0662.jpg (62.27 kB . 1024x576 - viewed 203 times)
Final mechanics:
*DSC_0663.jpg (69.74 kB . 1024x576 - viewed 201 times)

Build so far went straight, no troubles at all, only issue I have encountered was a misalignment on the Y motor gear by my mistake.

This is where I took a brake to eat next step was the extruder. It's the most complicated part of the build by most accounts. I forgot to snap pics during this phase though.

Putting the extruder together went smooth except for the final steps where I did not pay attention and did not pull the cables trough the channels made for the purpose, the extruder parts are black and combined with the poor lighting conditions it's easy to miss.

Another observation is regarding the printed manual, while it's nice to have I had to resort to the online version as you can magnify the pictures, especially towards the end of the build where there are lots of black parts.

Assembly ... continued

So as I have already mentioned I got focused on the extruder part and forgot to take pics till finished.

Between the last pics above and the ones below I had to cover the following:

- extruder assembly - it took at least an hour, a fairly complicated but very nicely designed part, great attention is required with the cabling and the nut inserts
- adding the e3d to it - you just push it in and done
- add the fans
- add the extruder motor and align and tension the bondtech parts - patience and grace required, the assembly is tricky and there is this idler printed part which has a bit of a too short 3mm rod which needs to get centered properly to support both sides of the idler ... maybe next time I have to open that part up add a longer pin.
- route the wires to the back and clamp everything together - and that is the extruder

note: I got the latest revision of the parts B7 and the online manual is split to take this into account you just have to pay attention. 

Next was adding the hotbed and the psu - straight forward no real issues there.

The last part of the build consists of cable management and adding the electronics.

Managing the cables is a pain point in most of my builds however Prusa makes sure to give you lots of help there with channels on the extruder and ziptie points all over the frame.
Also a note here: The original kits came with spiral cable covers now they have switched to textile covers. I got the textile ones and I think I have managed to get them in place pretty nicely.

Finally it's complete! Total building time with some brakes included: around 8h. I think it's doable in a shorter time but there was no hurry so there you go.

Now comes the flight precheck part, basically making sure the X,Y, Z are somewhat in proper shape for the calibration.

Next was powering it up ... Woo no smoke :D

First boot will take you to the setup wizard which will guide you trough the calibration Joseph Prusa himself guides you trough it!

To make up for it here are some pics after:

The finished Prusa on it's table:
*DSC_0664.jpg (93.7 kB . 1024x576 - viewed 211 times)

Part 2 - Upgrades!

Since the Einsy board is already provisioned with a raspberry pi zero connector why not use it?
Prusa also thought so so they provided a guide on how to add the pi to your build here:

I just followed the steps, printed the parts, etc, until I got the the pins. I have completely  failed to pay attention to the orientation of the board so I have managed to put the pins on the wrong side of the board  :(
After a lot of careful prying on them I have managed to move them to the proper placing, wrote the image to the sd card, added my wifi creds, put the card in the pi, monted it on the machine and voila Octoprint! Pics below.

Preparing the rpi zero w for Octoprint enabling:
*DSC_0665.jpg (61.72 kB . 1024x576 - viewed 215 times)
*DSC_0666.jpg (60.74 kB . 1024x576 - viewed 199 times)
Aaand of course I got the pins on the wrong side of the board ... mirrored :/
*DSC_0667.jpg (47.34 kB . 1024x576 - viewed 191 times)
*DSC_0668.jpg (75.09 kB . 1024x576 - viewed 189 times)
Fixed ... after a fight to get the pins out.
*DSC_0669.jpg (69.54 kB . 1024x576 - viewed 194 times)
And mounted on the printer.
*DSC_0670.jpg (68.99 kB . 1024x576 - viewed 205 times)
*DSC_0671.jpg (46.97 kB . 1024x576 - viewed 185 times)
*DSC_0672.jpg (40.2 kB . 1024x576 - viewed 191 times)
*DSC_0673.jpg (41.54 kB . 1024x576 - viewed 184 times)
*DSC_0674.jpg (42.24 kB . 1024x576 - viewed 193 times)

It printed quite well both from Cura and Slic3rPE, from serial or SDCard.

One thing that bothered me was the belt idlers being toothless so I replaced them with my own (chinese) toothed ones, not quite sure if it helps in any way except for reducing vibrations and maybe noise.

I have measured the parts, x/y/z sizes are on the mark so even though my belts are not the same tension, the firmware mods Prusa did to Marlin are really great!

One issue I've noticed is parts are not sticking very well even with the heatbed and all, Prusa recommends cleaning the bed after each use with isopropilic alcohol I don't have around at this point, I'll update once I can comment on that.
Finally the parts are coming out great, there are some artifacts which are well in the "normal" range for a FDM based printer.

I did not do any real tunning so far,  it might be overextruding just a bit but I don't want to mess with it to much at this point.

Regarding the profiles for Slic3rPE there is a (peculiar to me) choice on 0.45 extrusion width for the layer, not sure why not 0.4 but to my previous experience Slic3r doe have a weird way of calculating this which never really produced great results for me, so Prusa Research might be on to something.

As for Cura well the profiles are a bit hard to get in there but once done it does print fairly well ... except for retraction blobs here and there (I don't think they spent much time on that though).  This might be some tunning on my part to do... Still the same goes for slic3r so not quite settled on what to actually use for now.

Well this concludes my build and my thoughts on it so far.

Final take? Well I did recommend people to get a Prusa before and I'm standing by my choice. Now that I managed to get mine it's all what I had expected no surprises there. It is a stable build, very well supported by a huge community and in a state of continuous development and improvement.

There are some mild hiccups along the way but hey  it's a kit you build.

Is is it worth the price you pay? I would say yes, the quality of all parts is above the cheaper kits by far. Only adding the e3d original, the bondtech gears and the Einsy electronics gives around 300 Euros.  Add to it the custom hotbed, the build plates, the branded motors, the wiring, the custom frame ... yup that will go around 500 - 600 Euros and there you go. 

That's all I have so far, signing off,

« Last Edit: November 30, 2018, 04:38:10 AM by tinhead »


  • Member
  • *
  • B
  • Posts: 85
Re: The Original Prusa I3 Mk3
« Reply #1 on: November 25, 2018, 04:40:31 AM »
Nice kit :) Big benefit is if you have any issues with it there is a big company and community to help you. But it's bloody expensive for a Prusa I3 style printer.


  • Member
  • ****
  • t
  • Posts: 47
Re: The Original Prusa I3 Mk3
« Reply #2 on: November 25, 2018, 06:11:22 AM »
Yup it is not cheap at all but still compared to things like Ultimaker it is a lot better.
I don't expect any issues with the build but let's see how it goes  :)


  • Member
  • *
  • B
  • Posts: 85
Re: The Original Prusa I3 Mk3
« Reply #3 on: November 25, 2018, 07:54:21 AM »
I looked into buying one before I built my P3steel printer. That's some time ago, the kit has improved quite a bit since then. Back then I was not convinced with the frame / many printed parts of the kit. That's one of the reasons I built a P3steel. I move my printer regularly, then it's a real benefit to have a sturdy chassis.
Print quality should be high, E3D V6 and the Bondtech extruder are high quality parts. My own printer uses (genuine) E3D V6 hot end and an E3D Titan extruder. I'm very happy with that combination.


  • calling from free Europe
  • Moderator
  • Sr. Member
  • *****
  • Posts: 469
Re: The Original Prusa I3 Mk3
« Reply #4 on: November 26, 2018, 02:24:05 PM »
Think its a good call TH,, you bashed enough parts together ^-^ ..... am curious thou you gonna upgrade  to multi martial 
I build bots


  • Member
  • ****
  • t
  • Posts: 47
Re: The Original Prusa I3 Mk3
« Reply #5 on: November 26, 2018, 02:42:26 PM »
That would be another 300 Euros hmm maybe the Easter Bunny can help... ;)


  • Member
  • ****
  • t
  • Posts: 47
Re: The Original Prusa I3 Mk3
« Reply #6 on: November 30, 2018, 04:38:53 AM »
Updated, bump!


  • Member
  • *
  • B
  • Posts: 85
Re: The Original Prusa I3 Mk3
« Reply #7 on: November 30, 2018, 02:26:48 PM »
I've never used toothed pulleys on the idlers. Don't think they are necessary?


  • Member
  • ****
  • t
  • Posts: 47
Re: The Original Prusa I3 Mk3
« Reply #8 on: November 30, 2018, 02:49:52 PM »
Well belt has teeth rubbing on the flat pulleys, if nothing else at least the belt sits better. I had them already so why not try?

Oh yeah and there is the diameter which is about one... Or so smaller on the teeth iders so belt is going straighter horizontally... Neat.


* Search

* Recent Topics

Saturn pics anyone by James
[September 17, 2019, 08:09:06 AM]

Hello Robot Rebels by Passixs
[September 15, 2019, 10:19:10 PM]

All Ya'll. And me. by James
[September 09, 2019, 10:35:19 PM]

MSD - Motorized solder dispenser (Work in progress) by James
[September 09, 2019, 08:45:29 PM]

It may be dangerous to work in the virtual realm by ZeroMax
[September 05, 2019, 05:55:16 PM]

"1984 Nixie Time" by Gareth
[August 25, 2019, 12:21:58 PM]

Just wanted to say Hi. by ErwinCanto
[August 18, 2019, 10:11:28 PM]

SDR (Software Defined Radio) by Gareth
[August 14, 2019, 01:12:21 PM]

PLX-DAQ by AmandaG
[August 06, 2019, 01:58:42 PM]

DIY Yellow Servo by AmandaG
[August 06, 2019, 01:08:09 PM]

Comp? :o by Impala
[August 02, 2019, 07:32:20 PM]

Website to do list by Killer Angel
[August 02, 2019, 05:38:30 AM]

I Like the new front page! by James
[July 31, 2019, 12:29:53 AM]

Pictures on the front page! by tinhead
[July 30, 2019, 05:17:20 AM]

4x5 Macro Keypad by James
[July 28, 2019, 08:30:41 PM]

* Recent Posts

Re: Saturn pics anyone by James
[September 17, 2019, 08:09:06 AM]

Re: Saturn pics anyone by Passixs
[September 15, 2019, 10:23:38 PM]

Re: Hello Robot Rebels by Passixs
[September 15, 2019, 10:19:10 PM]

Re: All Ya'll. And me. by James
[September 09, 2019, 10:35:19 PM]

Re: MSD - Motorized solder dispenser (Work in progress) by James
[September 09, 2019, 08:45:29 PM]

Re: MSD - Motorized solder dispenser (Work in progress) by arclite7
[September 08, 2019, 04:17:21 AM]

Re: MSD - Motorized solder dispenser (Work in progress) by Gareth
[September 06, 2019, 05:18:40 AM]

All Ya'll. And me. by ZeroMax
[September 05, 2019, 05:56:35 PM]

Re: It may be dangerous to work in the virtual realm by ZeroMax
[September 05, 2019, 05:55:16 PM]

MSD - Motorized solder dispenser (Work in progress) by James
[September 01, 2019, 07:45:19 PM]

"1984 Nixie Time" Update 20190825 by Gareth
[August 25, 2019, 12:21:58 PM]

Re: "1984 Nixie Time" - Update 20190822 by Gareth
[August 22, 2019, 05:59:29 AM]

Re: "1984 Nixie Time" - Update by Gareth
[August 20, 2019, 11:15:36 AM]

Re: "1984 Nixie Time" by Bajdi
[August 20, 2019, 09:35:39 AM]

Just wanted to say Hi. by ErwinCanto
[August 18, 2019, 10:11:28 PM]