For a while now I have had the idea of designing and building a new 3D printer. The previous 3D printer I designed and built 5-6 years ago is still in use, but too often now I run into its limitations and it is starting to impact my workflow too much. My biggest issues with the old printer are that the build platform is too small (200*200mm) for my needs, it is a hassle to hook the printer up with an Ethernet cable for every print (a permanent cable between the router and printer would go across my walking path) and the printer is annoyingly loud. Aside from that there are also a bunch of smaller issues, such as misalignment problems that have crept in and components that are starting to wear out.
I thought about upgrading the old printer, but this is not feasible because of the Makerbeams that the frame is built out of. The 10x10mm aluminium extrusion was already a questionable choice for the frame when I started building the printer, but as I increased the build volume over time the lack of rigidity of the Makerbeams became quite clear. I had to reinforce the frame with a decent bit of cross-bracing and extra beams to make sure it did not flex too much during printing. Enlarging the frame to fit a 300*300mm build plate would require an even larger amount of extra reinforcement to keep it rigid enough. Considering the impracticality of that and the price of the Makerbeams (very high compared to 2020 or 3030 extrusion) I did not consider that to be a valid option.
The best thing to do in my opinion was to design and build a new printer from scratch. A big challenge, but also a lot of fun. Since building the last printer I have learnt a lot and would like to apply some of that new knowledge to the design of a new printer.
After sitting down and writing out the list of design goals for the new 3D printer I came up with the following (rough) list of goals/specifications:
- 300*300*~400mm print volume – This is big enough for any of my upcoming projects. Going even bigger would be excessive/impractical/expensive.
- 3030 extrusion for the frame – This should be sufficiently rigid for these printer dimensions. I am definitely making sure things are rigid enough this time around.
- 2020 extrusion for the moving parts – The X and Z gantries are kept as light as possible (while still being rigid) by using 2020 instead of 3030 extrusion.
- 240V heated bed – Powering the bed using mains power (as opposed to 12/24V) means the wiring does not have to carry as many amps which is a lot safer. Plus I can get a smaller power supply for the electronics.
- Linear rails for all axes – From what I read even the Chinese linear rails seem to be quite a bit more precise than linear rods and bearings. They are a bit more expensive (than linear rods/bearings) but I think they are worth the extra cost.
- Triple leadscrew + double linear rail setup for the Z axis – This seems to be the most stable way to move the Z gantry up and down without over-constraining it.
- CoreXY mechanics – This will be the same as the previous printer. Having the X/Y stepper motor mass mounted on the frame allows for faster acceleration of the XY carriage, less ringing, etc.
- Fully enclosed with acrylic/Plexiglas panels – The printer will be enclosed to dampen sound, to be able to heat the chamber to allow for printing of ABS and some other warpy plastics, to be able to filter any fumes, and to keep dust out of the printer.
- 32-bit controller – A bit of a no-brainer. The printer needs to be able to print with high speed, high acceleration, high resolution and as little noise as possible. An 8-bit controller simply doesn’t cut it.
- WiFi connectivity instead of Ethernet – No more Ethernet cables across my office. In combination with the 32-bit specification above the logical choice for a control board is the Duet 2 Wifi. This board also uses the TMC2660 stepper drivers which can run the steppers silently using 1/256-step microstepping.
- Touch screen interface – I will be controlling the 3D printer mostly over WiFi, but it might be useful to be able to control it standalone sometimes. Plus I think having a touch screen on the printer is awesome.
Over the last couple months I designed most of the printer in SOLIDWORKS, and the majority of parts have been ordered and have since arrived. I have started the build itself as well:
The next step is to install the Z gantry in the 3D printer and properly align all linear rails and lead screws. This is a step that I expect to be very tedious and to take up the most time. Not coincidentally it is also the step I am looking the least forward to. I will do this in the next part of this article series.