New Printrbot Plus V2 – Scrap Built

Posted: August 5, 2017 in Uncategorized

If you have followed, I tried adding a plastic extruder to my CNC Router. The results were less than desirable. Not horrible all of the time but terribly unreliable. So, I finally decided to build my own 3D printer. Having studied RepRap and many other printers I settled on something that I could build with the tools I had, a CNC router. I started out with the items I had:

  • 650watt PSU (Computer power supply)
  • Printrbot Geared Extruder and hotend
  • Heated Bed
  • 2 x T2.5 10 tooth sprocket
  • 1m of T2.5 reinforced belt
  • Ramps 1.4 board (Bought as a kit and assembled… That was hard, not for the faint of heart)

I had to gather a few other items:

I tried to get everything I could from Printrbot. This ensured compatibility as well as giving some money to the person who designed it to begin with. I also had to order a bunch of bolts to assemble the thing. I got these from boltdepot. I am not going to post that BOM as I was off on a few things. Follow the one on Printrbot’s website. It is “Mostly” right. I would recommend you get a few more #6-0.75 bolts and you will need some collars for roller bearings on the Y-Axis (More on that later).

The next step was to produce the wood parts. I downloaded the inventor files from printrbot.com and took the time to create DXF files of each part and loaded them into my CAM software:

The next challenge was trying to find the right wood. I never did… I ended up using the closed thing I could, 0.23in thick BC grade plywood (Yuck). I figured thickness was more important than quality. This decision would lead to voids the plywood causing some structural issues in some area. If I were to do this again I think I would special order. I optimized the CAM files for a 1/32in bit and added dog bones everywhere I needed to.

About 1 hour later I had a pile of parts:

I was ready to start. Except, my bolts still hadn’t come in. They would take another week to arrive, the Fedex ground that boltdepot.com uses is just too slow. Drop that stuff in a flat rate priority mail box and get it in a couple days.

Finally everything arrived and I got to building. You will notice that I spent the week waiting painting as much as I could. A nice satin white. I mentioned that you will need spacers that are not mentioned anywhere on the official BOM. This little 5/16in collars did the job great for me. I don’t remember where I got them, I have a whole pack from a project long ago. Another option would be to just use a 5/16in bolt. It is a little big though the wood, but it would work.

It took me two evening to assemble everything, but I am really happy with how it turned out.

Wiring was a bit of a pain. The RAMPS board can be a challenge. When you are setting the motor current and have all of the drivers plugged in, the ground for the current sense is right next to the VMOT pin. Well, I accidently shorted the two pins and blew a board. A quick Amazon order and the next day I had a replacement, time to get printing:

I printed a few pieces and quickly realized that the 1/4in thick aluminum plate was just not getting hot enough. With an IR thermometer I read it as reaching 80oC. I removed the plate and am printing now on kapton directly on top of my heated bed PCB. I am now able to get 110oC which has allowed the pieces to stick much better.

If you remember me talking about how the voids in the plywood were causing issues, my Z nut on the right side was working loose due to one of these voids. I decided that before things broke down too much I would print replacement Z nut traps.

It is not the prettiest piece ever, but remember the printer was only working in the Z axis on one side. I think given that, there aren’t too bad. I printed two, one for each side. These had another benefit that they decoupled the X-axis from the Z axis. I now have no Z-Wobble, while before it was pretty bad. The next immediate upgrade was to replace the plywood shaft couplings on the Z-axis with printed ones. I found a decent coupe on thingiverse and customized it to the 5/16in diameter threaded rod:

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