Project: converting the Anet A8 to a CoreXY type 3D printer

In the summer of 2017 I started the conversion of my Anet A8 3D printer to an AM8, essentialy replacing the flimsy acrylic frame of the printer with a new one made of aluminum profile extrusions. The conversion went well, and the robustness of the printer improved considerably.

A few months ago, an accident in connecting a power cable caused the need to replace the motherboard. The new board, a MKS Gen L 1.0 with TMC21100 stepper drivers, allowed for better print speeds but also revealed the limitations of the printer design. In particular, the operation of the Y-axis, with the entire heated bed moving back and forward, caused noise and vibration when printing at high speeds.

So, now that it’s summer again, it was time for redesign. This time I chose a CoreXY style with two stepper motors working together for moving the X and Y axes, and the heated bed only moving up and down on the Z axis.

One of the most popular such designs is the HypeCube Evolution that uses 3030 aluminum profile extrusions for robust construction that allows for print volumes of 300x300x300.

In order to minimize the cost of the conversion I thought to use as many of the existing Anet parts as possible. Luckily I was not first to think like that. There is already a similar project, called Anet Evolution, based on the Hypercube Evolution, but adapted to use the Anet A8 threaded and smooth rods, print bed, and print head, on a 2020 profile frame for lower cost.

So I based my conversion on this, with a few changes:

  • To better fit the electronics at the bottom of the frame, I used longer vertical 2020 extrusions (540mm instead of 500mm) and 2040 extrusions for the base.
  • I changed the print head because I have been using a E3D V6 head in a Bowden design for a long time and did not want to switch back to the Anet MK8 direct extruder.

For mounting the electronics (the board, the 2 MOSFETs, the Raspberry Pi 3B and it’s DC-DC converter), I used a 460×420 acrylic panel screwed under the aluminum frame.

As measured after fitting the X & Y axis and the print head, the maximum build area of the printer is aproximetely 260×270. In a future upgrade I might swap the print bed for a larger one without the need of any other modifications.

As you can see at the photos, it’s still a work in progress. The basic parts are in place but I need to do the wiring (and because I want to do a neat job at that, it will take me some more time).

Parts Used:

The Aluminum Extrusions were purchased online on CNC CAT. Most other parts were purchased online on AliExpress or localy.

Aluminum Extrusions:

  • 4x 380mm 2020 Extrusion
  • 2x 380mm 2040 Extrusion
  • 2x 420mm 2020 Extrusion
  • 2x 420mm 2040 Extrusion
  • 4x 540mm 2020 Extrusion
  • 2x 410mm 2020 Extrusion (for the bed)
  • 2x 240mm 2020 Extrusion (for the bed)

Connectors:

  • 32x T-Slot L-Shape 2020 Aluminum Profile Interior Corner Connector Joint Bracket for 2020 Alu-profile (with M4 screws)
  • 4x 2020 Corner Bracket

Screws etc:

  • 5×10 Button head philips screws
  • 5×20 Button head philips screws
  • 4×10 Button head philips screws
  • M3x10 Socket head screws
  • M3x10 Socket head screws
  • M3x12 Socket head screws
  • M3x16 Socket head screws
  • M3x20 Socket head screws
  • M3x25 Socket head screws
  • M5 Drop-In T Nuts for 2020 profile
  • M3x5x5mm Brass Knurl Round Insert Nuts
  • Various other nuts and washers

Belts and Pulleys:

  • 6 x GT2 Idler Pulley (20 teeth) 3mm
  • 2 x GT2 Idler Pulley without teeth (20 teeth) 3mm
  • 5m GT2 6mm Reinforced Belt

Printed Parts Used:

The printed parts were made on my AM8, using black PETG filament.

I will upload my custom designed parts on thingiverse as soon as I complete the build and confirm it’s working as intended.

To Do List:

  • Decide on the placement of the Power Supply (at the back or at the bottom of the frame)
  • Wiring everything (neatly)
  • Adding a second acrylic panel on top of the electronics, with corresponding holes for cooling fans
  • Mounting the Graphics Controller on the lower front left side of the frame
  • Incorporating a Filament Spool Holder, probably on the lower right side of the frame
  • Adding a second pair of vertical smooth rods on the right side of the Z-Frame
  • Adding a LED strip on the top edge of the frame
  • Decide on the placement of the Pi-Cam