Printrbot Jr. Arrives…. mostly

Its been a fun week… first the laser and now the Printrbot Jr. arrived last night!

We weren’t going to build the printer until this weekend, but decided to take a look at all the pretty wood pieces. Printrbot has a nice diagram ( showing all the laser cut pieces so we laid it all out just to make sure we had them all.


Dang! We are missing part 326!!!! Printrbot doesn’t have the design files up for this printer yet, so I posted on the Printrbot forums to see if anyone had one of these parts kicking around that they could measure up for me. I also put in a support request on the Printrbot website saying that I had a missing part.

They shipped out a replacement part gratis about 30 minutes later! Wow. Awesome service. No response on the forum from other users though. Just not enough Jr. printers out in the wild yet I guess.

But who the heck wants to wait a week for that part??? So I did some googling and found a nice picture of the missing part.

Looks easy enough. Its just holding two piece of wood together which trap a nut on the z-axis drive. The outside dimensions aren’t critical, so just a matter of getting the inside right.

I took the pdf from their website and imported it into CorelDraw. I then took a few measurements of the parts that will plug into this and resized the pdf of part 326 up to what I figured I needed.

I then fired up the frikkin’ laser! Well…. actually I did a test cut on the plywood to find a nice speed and power level which would blast through some 1/4″ plywood in one cut. After a couple of attempts, I found that 5mm/s and 15mA did it nicely… just barely pops the laser through the other side. Perfect. Put a new piece on the table and started cutting. Less than a minute later, out pops the missing 326!

Perfect fit on the first try! Crazy luck. Its a little more snug than the Printrbot cuts which is nice. Looks like Printrbot uses plywood which is 5.5mm thick instead of 6mm (1/4″). What the heck??? Anyhow, makes no difference on this part so I’m not sweating it.

Ready to hand off to the kids for the big assemble starting tomorrow! Its too bad that we won’t have it built in time for the Maker Faire happening in Ottawa this weekend, but those are the breaks I guess.

So the laser is proving useful already. I could have cut that on the CNC mill I suppose, but the laser is much more fun. And incredibly fast in comparison.

Below is my first object that I cut out instead of just engraving. It actually took me 7 tries before I found the right combo of speed and current to be able to get it in one shot. The laser was able to repeatably trace over the same thing 7 times which was nice to see. No missing steps from the looks of it.

Also tried to engrave an Aztec calendar on some crummy wood. Tried it 2 different ways just for the fun of it. It came out not too bad it the one of the right smoked like crazy so the details are lost. I’m going to have to put an air assist nozzle on pretty soon!


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5 Responses to Printrbot Jr. Arrives…. mostly

  1. Nick says:

    Hello Aaron,

    how’s the printer doing? Have you tried it out?
    Was thinking of buying one but would prefer to be reassured about the quality/usability…

  2. Aaron Ramsey says:

    The printer is pretty good. I’ll post up some pictures this weekend showing a print. I’ve struggled a bit getting the PLA to stick to the bed. I was spoiled by my other printer with the heated bed…. that really makes it much easier. I may end up building a PCB for heating the bed, but first I’m going to try and get the bed a little more level to see if that helps.

    I think that the plywood print bed bows a bit across itself. If I level the 4 corners I end up with the middle slightly higher (maybe 0.1mm or so). Its not much, but its enough that my prints smoosh a bit in the middle and make a mess. If I compensate for that, then the filament doesn’t stick well when printing away from the middle. Printing with a raft works nicely, but I hate peeling a raft off the bottom when I’m done. 😉

    My plan is to remove the bed completely and mount a piece of glass instead. It should be a little more flat and make it easier to get everything nice and level.

  3. Michelle says:

    Hi there! We just got our printrbot jr. put together here in Kansas City, but are having trouble finding info on some basics to put into Slic3r, such as the optimal print bed size, and extrusion temp. Have you had any luck getting a good print with PLA? What settings did you use?

    • Aaron Ramsey says:


      Sorry for the late reply. I’m using Kisslicer for slicing instead of Slic3r. I’ve found that its a little more reliable at this point. I’m happy to share the Kisslicer config files as a starting point for you if you are still interested.

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