My Thoughts on the Printrbot Jr.

Ive had my printrbot jr for around a week now, and I figured I’d post of what I like and dislike about the printer. I bought the kit since it was cheaper and I thought it’d be cool to just put it together myself in case something ever happened to it, then I knew how it went together and how it worked so I could fix it.

The Bad:

When I put it together, they do not put the instructions to put it together in with the printer itself, which in a way is annoying, yet kinda cool because they rather show it being put together rather than just vague pictures, which you’ll find all of the parts on youtube. There’s also pages which show how to assemble everything which goes into more detail than he does in the video as the webpages and youtube videos seem to compliment each other. One thing I did realize is that they do not have the instructions to build the extruder with the instructions to build the printer kit, so you have to search the site or just google it to find how it goes together.

After I finally got everything and assembled, the fan cables either got shorted from moving the axis around, or came that way from the factory, and blew up the mosfet that controlled the fan. The thing refused to move any motors, and if I turned on the print head, it would heat up and everything fine, but motors wouldnt do anything. If I turned on the fan in repetier host, at around 60-85%, it would cause the Y axis motor to just buzz and I thought the board was dead. Later I found out that the fan was causing all of the issues and when I disconnected it, the printer ran fine. I ended up just taking the fan off and when I was taking it off, I saw the shorted wires where they frayed and shorted each other out, so I soldered them back how they were supposed to be and stuck a drop of conformal coating that you use with PCBs and put it back together and it worked fine.

After that issue was resolved, I discovered that most of the time, you need to have the USB plugged in before you plug in the power cord, or it wont detect the printer on the computer for some odd reason, but that’s an easy enough thing to fix. Just have to plug in the printer at the same time or after the computer. I use a Raspberry Pi system as a low powered print server/torrent server/web server, and I use repetier host software to convert the STL files to gcode. I run OctoPrint on the rpi bc in all honesty, it seems to run better and with alot less problems with trying to print some gcode like repetier-server. So just hook it up to the same power strip, and they both turn on at the same time.

Last things I noticed is that the Y endstop bolt is a bit too short, but I may have accidently used it in another location and the X axis wants to home to the right, which is backwards since the endstop switch is to the left. A little searching online found that some people had this issue, and it was a piece of cake to fix, just either put the X axis belt on upside down, or move 4 wires around in the connector, easy to do, but it could be corrected in firmware later on.

The Good:

The printer was fairly easy to put together and the webpage versions of the instructions were pretty easy to understand, they have a really nice export to pdf function that I used to save the instructions and had it running from my laptop, so I had everything all together in one place. The print quality is actually pretty good from what Ive seen, just watch your temperatures and it should print fairly decent prints. I do like the look of it, it’s very clean looking, and almost a steampunk’ish look to it. Also from seeing people online while researching taking 9-12 hours to print something, I was expecting it to be really slow, but the Printrbot Jr is actually pretty quick. I printed off a bunch of space invaders guitar picks, and it took like 5-10 minutes.

The PLA plastic is pretty neat, and sticks pretty easily, I use the blue painter’s tape, and it seems to stick to that fairly decent, but at times, it tends to be stubborn on the first layer on sticking to the print area, but just set the printer to heat up and let it preheat for around 3-5 minutes when it reaches the first layer temperature, and it sticks perfectly fine, it just needs to get the metal nozzle and such heated up inside. Only thing I have to warn you about PLA is that if you make supports on it, dont try using a knife trying to cut it out, just get the pliers. the plastic is very strong, and even my smaller items, Ive tried breaking them and like the guitar picks, I gave alot of my strength into trying to snap one, and still couldnt even make it budge. People talk about the lower melting point being an issue, but in all honesty, unless your putting it somewhere where it’ll get super hot, like around high current motors, or a flame, it’ll stand up to most stuff you throw it it. It is biodegradable, but it doesnt mean it’ll just wash away when it comes around water. They’re making pins for the hospitals out of PLA now because of the fact that it does dissolve, but it’s slow enough that it lets the bone grow back before it’s gone, which takes around 7-8 months. So 7-8 months submerged in liquid, that’s good enough for me. Just throw on some paint on the stuff, or laquer and it’ll be good to go forever.

Like I said before, the print quality is pretty good, it isnt like glass smooth coming out, but a little sandpaper and paint, and you’ll never know it came from a printer. The print area is alot bigger than I originally thought, I thought it would be around the size of a coffee cup or so, but that’s not even true. If you fold a normal sheet of paper in half, top to bottom, that’s around the size of the print area of it.

Ive been running mine at 195C when doing the first layer, and 190 for the rest of the layers, and it gives quite good results. Just set up the options in repetier-host when your setting up everything, and it’ll be good to go from then on.

While putting it together, you’ll notice that the bearings and motors are of the highest quality, and every other part is custom made. Im fairly certain that all of the wood parts and everything are made in shop at Printrbot, and everything is very tight to put together, but a little sandpaper and everything fits very snug and tight. Another thing is, and is nice, it is open source hardware, so if anything ever breaks down, the schematics and everything are available online to help figure out where the issues are and how to fix the issues. Also something that I noticed, there is no cheap, “made in china” stuff with this printer, I believe that everything is made in the US.

Also, people say about the smells of the plastic, and in all honesty, when Im printing stuff off with PLA, I dont smell anything other than a faint smell that you only notice after printing for like 8 or 9 hours straight (guilty of that :P)Ā  The printer is fairly quiet, and if you have a laser printer, or used a laser printer, it’s no louder than that.

If you have any issues at all, the printrbot site has a main forum which the admins seem to browse daily, and seem really helpful. If they dont answer your question right away, dont think it’s getting ignored, it may take a day or two to get a reply because of them trying to reproduce the issue.

The conclusion:

Overall, I think it’s a really great printer, it had that one little hiccup at the beginning, but after that, the little things are a piece of cake to get around, and you can hook it up to almost anything and run it off of that. I had my little fake raspberry pi netbook running it for a few days until I finally decided that I rather have my netbook back and hooked up the raspberry pi rather than needing to sit there at the desk all the time waiting on it to print. Just convert the stuff to gcode, go to the page on the rpi, upload the gcode file, and click print. Easy as pi šŸ˜›

Most people will just hook it up to the same computer that is running repetier-host, and will run it like that, but I like having freedom to just throw a bit of code on there from my laptop and take the laptop off to work on something else while it’s printing.

Also Ive discovered that if you have the large rubber feet for like you’d use on the inside of cabinets, and put them on your table around the printer, it helps a ton because the printer loves to shake a ton when printing from the speed of it printing and all of the axes going all over the place shifting the weight. The printer is very sturdy and wont come apart, even with all of the vibration and shaking, so that’s not an issue.

The printer is a really good way to fix those little things you have around the house and get your foot in the door with 3d printing. If you have a bit of patience and are adventurous about how things work like me, I would get the kit, it’s cheaper, but there may be a small hiccup here or there when your first getting started, but overall, Im quite happy with the quality of the product. If you just want to get straight into 3d printing, I’d just get the assembled version, and then you wont have any issues.

On a rating of 1-10, I’d have to give the printer around an 8.5/10, if I wouldnt have had the little fan hiccup, I would have given 9.5/10. And I would reccommend it to those who are getting into 3d printing.

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2 Responses to My Thoughts on the Printrbot Jr.

  1. Karen L says:

    I so enjoyed reading about this! Thanks for sharing.

    Do you have to use pellets or can you use sheets? And how do you determine the quantity of material for each project? Of course, using sheets would be the same as paper when figuring, but if you are using pellets and extruding them, that would be different. Can the thickness of different parts you want to make be adjusted?

    • cae2100 says:

      it just uses the filament, 1.75mm filament, and no sheets or pellets here. The thickness of the layers are adjustable, but I havnt really played with those settings that much yet. The pellets are designed for the really expensive printers, like the 10,000 dollar ones and up I believe. There is a few projects floating around the open source communities like the filastruder that is homemade options that will feed in pellets and scrap prints, and shred the plastic and extrude it into a filament. Maybe later on down the road, Ill look into that option, but atm, Im just using the filament. I have around 3 big spools of the natural PLA, and each spool is around 1,000 feet, which cost around 30 dollars, so not really that much in a rush into making more filament atm. šŸ˜›

      As for the materials and the quantity of the material, it’ll show how much is going to be used right on the screen when you convert it to gcode and it also shows it in octoprint while it’s printing. Most of the time, I use a honeycomb filler, and it doesnt really use up that much filament. Ive printed almost nonstop for a few days, and Ive barely put a dent in my spool’s supply.

      For the best place that Ive found to get the filament, the stuff at printrbot seems to be the cheapest, at around 30 dollars unlike most places which are 40-45 per spool, and the quality seems to be really good. No real moisture in it like you hear about on various places online. The only thing is, they only have natural color, which is like kinda a milky clear color, but all you need to do is just paint it, or color it with a marker since it really works good like that too, and your good to go. When I go to makerfaire, Ill take a little money with me because you can buy the filaments in all colors up there.

      You can technically run ABS plastic in it, but you need an addon which is the heated printerbed, which I may look into later. ABS is the same thing that legos are made up, but smell aweful when printing. (smells like burning plastic) The reason why it needs the heated bed is because ABS loves to curl upwards if it’s not printed on a hot surface and your prints will just bow and pop off, and destroy themselves.

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