Review: My Printrbot Simple 3D Printer

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Owning a 3D Printer is great. It is hands down the best tool I own (right next to my handy dandy Dremel). I purchased the Printrbot Simple back in December of 2013, it was a Christmas gift to myself. They no longer sell the exact model that I bought, so don't go looking for it, but I highly recommend getting a PrintrBot printer brand printer. I bought the "Assemble-it-yourself" kit, because it was 100 bucks cheaper. I also recommend doing that, regardless of your experience level (I'll touch more on that later). I put it together over the course of 2 days, and it printed well right off the bat. The one issue with it is its print volume is 4x4x4, so I am sort of limited with what I can do with it. But with a little bit of design work and thinking, you can make parts interlockable and forgo the limited volume issue (For example in my Custom Linear Actuator Project). All things considered I'd say the printer is a 9 out of 10.

An image of the PrintrBot Simple after my very first print.
An image of the PrintrBot Simple after my very first print.

Construction

Putting the Printrbot Simple (PB Simple) together was an awesome experience, especially for a young and enthusiastic electrical engineering student. The instructions on Printrbot's website were done very thoroughly in my opinion, with pictures detailing every single step. The laser-cut wood pieces came in sheets and I had to punch them out myself (sometimes with some coaxing from a razer blade). There was a bit of gluing, a lot of screwing, and a little bit of redoing (disclaimer: this rhyme was unintentional). Not only was the experience fun, but it was educational in 2 ways. One thing I got out of the experience was how basic CNC robotics should work in terms of bearings, actuation, and packaging. It taught me some principles that I've already applied to some other projects. The second thing I learned was how the machine worked, and how I'll be able to fix it. Putting it together gave me a good sense of where things were, and what could go wrong.

Operating the Printrbot Simple

At the time of writing, I have no issues operating the PB Simple. I have it set up (per PB's instruction) to work with Repetier Host  and I also find the software to be very simple. However, I have had some issues that I mostly attribute to user error and ignorance. These are some of the issues I ran/run into:

  • Royally screwing up the firmware: So when I first started out, I had accidently set up the end-stop values incorrectly, and the printer started to over-extend its X-axis. I panicked and hit the E-Stop button on the software and it didn't stop it, and then I unplugged communication to the control board (Yes I know I am dumb.) After getting things set up right, my printer did not work correctly by any means. I eventually found that the firmware somehow got messed up in that stint, and I needed to re-flash it. So; more learning experiences. After some digging and researching in Printrbot's website, I figured out how to flash the board, and within a few hours, fixed this issue.
  • Leveling the Bed: Once everything settled, I found that to keep my print bed level, I have to have the rear end of the bed as high as it will go, and my front as low as it will go. So not much room for adjustments. I attribute this to the fact that the printer arm sags the further it extends.
  • Tensioner too loose: This has bit me a couple times. When I first started out I most definitely did not have the tensioner tight enough. The issue was fine for awhile but eventually I started to notice splotchy-ness in my parts. The plastic bead the printer extruded would very in thickness in a very jittery fashion. Eventually, while troubleshooting this issue, I noticed that the extruder stopped extruding plastic entirely. I could see that the gear was turning, but it wasn't gripping the plastic. After some disassembling (minor) I found that my extruder gear had completely ate up some plastic and nearly clogged all of the teeth with plastic dust. So I cleaned the extruder gear with a needle, and retensioned it. I have to keep an eye on the tensioning screw, as it seems to wiggle its way a little loose from time to time.
  • Hot end clogged: I had similar conditions to when the tensioner was loose, but determined that it was not the problem. So I took the hot end apart, and took a look at the extruder tip. It had a lot of gunk in it on both sides. So I scraped off what I could, but that wasn't enough. Next, I stole some nail polish remover (acetone) from my girlfriend, and soaked the brass piece. I let it set in a closed container for a good 2 days, and then cleaned it with a toothpick and some cotton swabs. There was a bit that I couldn't get, so I bought one of those needle threader things and cut it in half. I used the stiff but thin metal wire to scrape the inside of the hot end hole completely clean. Things worked well after that.
  • I needed something to spool out the plastic: If I didn't have anything for the plastic spool to rotate on, it definitely would get tangled or cause to much tension and mess up the response of the extruder. This problem was quickly remedied by buying one of those cardboard book boxes, cutting slots in it, and placing a PVC pipe through it. This solution has worked for 3 years now.
The Printrbot printing a semi-solid gear (note the really loose tensioner screw. Oops)
The Printrbot printing a semi-solid gear (note the really loose tensioner screw. Oops)

As I said, most of these issues are completely due to me being inexperienced. Now I can run for very long stretches of time with no errors what so ever. I have also done some experimentation with temperatures and other print settings to completely optimize my prints. I highly recommend going through this process with a standard calibration piece to compare results from slightly changed settings. That brings me to my next thought; calibration. I have only calibrated this guy one time. I carried out a procedure similar to this one, except I used a dial indicator to make very precise measurements in axial movement. The process was very simple, and has been very effective. I had assumed that the machine would very in performance due to wood constantly warping due to atmospheric conditions. But it appears this is never really an issue.

Quality of Prints

The print quality is often very good. I typically will print at a resolution of 0.4mm I can do some things at smaller resolution (Like Dungeons and Dragons Mini-figures) but Z-axis movement errors start to compound, and the extruder will smear through the plastic. But when ever I print with my "Standard Settings" The quality is just as good as any other printer. One thing I found is that printing a skirt loop is absolutely necessary. When I first start my print, the heater will take about 3 to 4 minutes to heat up to 210º. During that time the extruder will "dribble" and two things will happen. One, it will smear plastic all over the place. Two, it will leave the extruder empty for awhile, and so the first layer won't have material to print with. So this is solved with a skirt ring around the model. It get's the extruder flowing well before starting on the actual model. By doing this, and making sure my bed is always level, my prints always come out just fine!

A 3D Printed pieces for the board game "Settlers of Catan"
A 3D Printed pieces for the board game "Settlers of Catan"

 

Everything Else

This wooden printer looks great sitting on my wooden desk. It certainly has a "raw" character that the engineer and tinkerer in me loves. It's footprint is small. It's very easy to use, and not really loud. I like printing in PLA because it smells good too. In general, owning a 3D printer is great, and allows me to bring some of my ideas to reality in a very quick fashion. Plastic is cheap and easy to work with. Get a 3D printer, make new things, and be awesome. I definitely recommend Printrbot brand printers.

A custom designed peice for my ACAPP Project.
A custom designed peice for my ACAPP Project.
A 3D Printed clip used to hold 2 peices of chemistry glassware
A 3D Printed clip used to hold 2 peices of chemistry glassware