Prusa i3

After building a Wolfstrap, designing my own printer, and building it, I had a couple of other design ideas going through my head.
After a while I thought to myself, there are quite a few designs out there and they all more or less are just a variant of each other.
So why spend weeks, months or a year trying to make/develop one more? Challange I guess is a very valid point, but I decided for now to have a closer look at the Prusa i3 instead.

I like the design that Prusa has come up with in regards to the single plate version. It looks sleek and is quite easy to build. It can be separated into 2 parts and therefore easier to transport as well.

After downloading the openscad files and checking out the ALU frame design I realised that this has got a lot of potential (for modifications and improvements, if you feel like it.)
On my first version of the i3 I used the frame as it is, as I wanted to check this design in regards to printing quality.
During my first build I modified some of the parts for my second i3, added some new parts and also changed the frame. I have not implemented all these changes yet as I design and modify as I go along. My first i3 which you can see in the photos below uses standard frame.

The most noticable change I have done is that I have got rid of the belts altogether. After having great difficulties finding GT2 belts and pullies, without paying way too much, I had had enough. I redesigned the parts to use braid fishing line. Yes you read that correctly. My version of the i3 uses Spectra Braid for both X and Y axis. If I wanted to I can still change the braid with belts but it involves changing the x-carriage and the belt holder under the bed.
It can’t get any cheaper than that and the best of all is that it works extremely well!
One of the benefits are that I can now print my own pulleys as well. Though pulleys are probably the hardest parts to print as they need to be very accurate.

I also decided that on my i3 I would use a Bowden extruder. The weight of a normal extruder setup is way to high and it really makes it hard to developing a multi nozzle setup due to weight. Sure it can be done but the weight of the motors are way to high for my liking.

I designed my own bowden extruder to test and it works quite well. There are a lot of good designs out there to use. I did my own as I needed a direct drive using 608 bearings and could not find one.
Then I designed a new hotend as well. This time I went for a stainless steel hot end. It worked first go. I did a slight modification and have already printed multiple complete set of parts for more i3’s, using my new i3 and nozzle. I only use ABS (will be testing some PLA later).

I had to do a lot of tweaking to get the bowden to work the way I wanted, a bowden is a different ball game altogether compared to a normal setup. And I am still tweaking it.

The quality of the parts coming off this machine is very good.

Will try to add some build details and info a bit later but for now here are some early photos:

Prusa i3
Put together and playing with the idea of using braid as I have difficulties sourcing GT2 belts locally.

Prusa i3

And guess what? I have decided to stick to braid as it works fine!
This printer works very well, and it looks good, just look at this:


Ready to print another set of parts….



9 Responses to Prusa i3

  1. 3d printer says:

    Hi, please more info about redesigned parts so we could use braid fishing line?

  2. Hello
    I see you have a new hotend version. Could you pleaser give me more details about it?
    I see a led heatsink and a push fitting.
    Thanks in advance.

    • 3dprinterman says:

      Yes the hot end is a small body of 8mm round stainless steel s304 with a ptfe tube inside. It has a M5 thread both ends. On top the coupling for the bowden tube. On the bottom there is a brass nozzle with a 0.3mm hole.
      The LED heatsink removes just enough heat to allow it to work with ABS.
      I have made another one……all metal but with a fan and no heatsink…..and it works for both PLA and ABS…
      But more about that one later.

  3. I’m glad I discovered your page. I’m looking at trying to build my own printer. I have some steppers in the junkbox, but they may be either too weak, or are the HV kind. I have two NEMA23’s with gear reduction drives, bi-polar (6 wire) rated at 8/6 volts, but with the gear drive are 0.1deg/step! Maybe I could use one of these with a belt for the Z axis? Also two 5v/1A nema23’s that should be powerfull enough for the X/Y axis. The handfull of Nema17’s I have are 4v/.95A six wire units that may be underpowered fo the job.
    I like your hotend / hotbed designs, and will probably try using one of them. Might also go with the drawer slides too. There is a maker fare/ Hamfest here tomorrow, maybe I can find some suitable parts (like stepper motors!).

  4. Goof says:

    Can you provide more detail on how you did the switch from pullies and belts to fishing line? I’m having hell getting the proper belts.

    • 3dprinterman says:

      My apologies for not responding quickly but I am hoping to add some details of what I have been doing the last year soon.
      The fishing line I use is the braid line type and it is 250lbs strength/thickness. Think I paid about $12 for 100m (very cheap).
      Have used thinner stuff as well but keep going back to the thicker stuff. It is about 1mm thick.
      I did have a “funny” problem with the line at one point but worked that out and will make some more detailed comments on that later.
      I use a v-groove bearing at one end and I print the pullies for the motors. It is very straight forward. The only special part is the pulley and the way I have designed the way I tension the line. Can be done in many ways but I have not altered mine since day one as it works fine.
      The printer I made first, the one in the photo, has held its tension on the line till today and have not needed any adjustments at all.
      Very happy with the way that works.
      Will publish some photos and probably the files as well in not too long so you can print them and try my way if you wish.

      Kind regards

  5. How have you mounted your printer? I see that you have placed it on a marble tile. Have you put anything in between the tile and the table to reduce the vibrations.

    • 3dprinterman says:

      The tile you see in the photo is a rubber tile, not marble.
      It costs around $12 and is excellent for dampening the noise BUT it really smells bad of rubber.
      So bad in fact that I ended up tossing it out with the rubbish.(recycled)
      What I am using now is just a small piece of carpet underlay. It reduces the noise by at least 75% I reckon.
      Have not noticed any side effects from having the soft underlay under the printers. And it allows me to run them at night in a room next to a bedroom.
      If you know anyone that are replacing their carpets you may find some usable underlay for free (just make sure it is clean).
      Or speak to a carpet layer (shop) and ask if they have some small pieces of underlay.
      You never know unless you ask.

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