The State of the Printrbot Simple

Back in the summer of 2014 I bought a Printrbot Simple 1405. It was a nice little printer with a build volume of 100x100x120mm. It took about two days to assemble to printer and another day to get the software working. This is one of the first thing is made, aSquartle on Printrbot Simple Low Poly Squirtle. This was an amazing start; to see a Pokemon built layer by layer was the coolest thing ever.

The Printrbot was great but the build volume was limiting and the cold aluminum bed led to a lot of curling prints. As a novice to 3D Printing, Thingiverse was my best friend. I was lucky enough to find that someone had already created the designs to make print volume larger.

The first mod was a simple x-axis size increase. With the x-axis size increased ever so slightly, I was then able to print the 300mm y-axis no sag mod. This gave my printer a massive theoretical y-axis length. Though in practice, the hotend will drop as it is pushed further out. However, it gave me enough build volume to print off the third mod, 1405 Simple X Expanded. Now my y-axis and x-axis are freed from the initial size constrains of the original Printrbot but in the process the Printrbot is noticeably less cute. Around this time I replaced the acme rod for a M5 threaded rod. This is the standard rod size used for most marlin based printers and allows for 100 micron printer height. On my printer is also these stabilizing legs for the larger print bed.

Printrbot Wood built plateNote on the evolution of the bed: the Printrbot comes with a polished aluminum build plate that is machined flat. After enlarging the size of my build platform I tried to drill holes in glass and screw this to the printer’s x-axis. This lead to several pains of glass shattering which I was very unhappy about. Next I used a wood built plate with a heated bed and glass put on top of all of that, pictured on the right. As you may already know, wood is fairly heavy. This leads to a lot of initial mass in the printer and the printer tends to shake a lot. I also had to use big metal washers to activate the Printrbot’s metal detecting end stop. My greatest achievement was discovering that the holes on the heated bed lined up perfectly with the holes on the printed x-axis supports. This allowed me to mount the bed on four screws with 4 springs. I stopped using the auto-leveling function of the printer because it was more reliable to level the bed myself with the four screws. I purchased a 300x200mm heated bed for my printer and began the search for a new printing surface. I bought a borax glass bed for the bed but that broke when an iPhone was dropped on it. My current printing surface is a 200x300x2mm sheet of carbon fiber I got from eBay. This is a beautifully strong and flat material to print on. I no longer fear glass shattering or falling iPhones.

The next mod I found by chance on Thingiverse while browsing. It’s called the Tri Rod Mod and is the greatest mod I have installed. It adds an extra rod to the y-axisPrintrbot feb and the z-axis. This adds an incredible amount of structure to the printer. It should also be noted that I am printing with the double precision edition of the x and y mods and I enjoy 160 steps/mm setting.

In the future I plan on extending the x-axis frame with this mod. However, the fully printed Printrbot frame is incompatible with the Tri Rod Mod. I will have to modify the frame to accommodate both mods. When I replace the last piece of wood with plastic, I also plan to replace the stepper motors with ones that have double the steps/rev of the current motors. I have no idea if the 320 steps/mm will increase the quality of prints but it is worth a try. I would also like to replace the noisy linear bearing with 3D printed bearings, once I buy the Bridge plastic.

Well that’s about all for my little Printrbot. My second printer is the Kossel mini and is now my pet project to upgrade. I hope you enjoyed reading my article 🙂


Shopping List:

Here is a cursory list of things you will need to upgrade your printer.

8 mm rod: **

  • 400 mm x3 for the y-axis, this will allow for about 200 mm of y travel space
  • 500 mm x3 for the z-axis, about 300 mm of vertical travel
  • 500 mm x2 for the x-axis, this will leave a little hang over on the ends of the axis as shown in the picture and allows for 300 mm travel

4 more Lm8uu bearings, I bought them from eBay. Buy more than you need because they aren’t always the best quality and buying more prevents you from using a noisy one.

GT2 timing belt: 1 meter per axis should be fine 300 mm on the x and 200 on the y.

M5 threaded rod and nuts

5mm to 5mm coulpler for the M5 rod to couple the motor

A new heated bed and a high power mosfet, the Printrbot has trouble powering a large bed. Don’t forget to use a proper power supply for the higher power demands of the large heated bed.

You’ll want some 40mm fans off eBay to cool different parts of the printer. Some wire is needed to extend the range of most 40mm fans to be powered from the power supply.

While I’m at it you should use a bigger power supply for the Printrbot. The one that comes with the printer doesn’t have enough current to drive a heated bed. I use an ATX power supply with two 12V rails. One is connected to the Printrbot and the other rail is connected to the heated bed using the high power switch. You could use two smaller ATX power supplies, 250W each, to power the board. You’ll also want to break out a 12V rail to power any additional fans. I used a proto board with standard headers to plug the fans into.

Update 24/2:
Someone has combined the tri rod mod with the fully printed frame! Will make the change when I get more filament.


Rods and screws with USPS shipping option.

eBay for most everything else.


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