Timeline
Lingfeng Wang
added to the journal ago
Linear Rail Design
I started with a simple sketch of its cross section. The bearings will be 5mm steel balls that I found laying around. I printed out a short ~10cm section of the track, and one of the things that rides on top. At the start, I used 6 balls as a contact, however I realized that this had too much friction. I tried a couple designs until I found one that worked
After trying it in person, I realised I could make the rail thinner, and a bit smaller, so I did that too. I spent quite a bit of time on refining the new cross section, ensuring that it would work well.
This worked well, but it still had a bit of friction. I looked online for other bearing designs, and I saw that they were quite complicated, requiring a loop of bearings. I decided that this was good enough, even though it isn’t a “real” linear rail.
The final linear rail I printed is alright for now, however it still had a bit of resistance since I was not able to make a linear rail with the complexity that was small enough to be used. The bearings drag along the rail more than roll, but there is not much I can do without making it twice as big and much more complex.
Lingfeng Wang
added to the journal ago
Starting ideas + little bit of CAD
To begin, before designing the CNC itself, I cadded the Nema 17 motors I chose for this project, and I sketched out a rough idea of what I want the CNC to look like. The entire CNC will be 3d printed, and roughly 15x15x15 cm. Each axis will be controlled by one Nema 17, using 3 in total.
Blue, Red, Green are the X, Z, Y Axes. The green lines are the moving parts of the frame, and the purple line is the hot wire.
The X (forward/back), Z (up/down) axes will be part of one CoreXY movement, and the Y (rotation) axis will be a geared down stepper.
Additionally, I cadded out the Nema 17 motor I will be using. I have quite a strange variant of Nema 17, and could not find it online. I also cadded out a limit switch using 5x5mm mouse switches, because I had them laying around. These should be the electronic components I will be using within the actual build, with the rest being outside of the main build (controller, drivers, etc).
Lingfeng Wang
started Foam CNC ago