H2 build report

[leehambley]

I started on a H2 build more than a year ago, but due to incompatibility between my lathe housing, and the H2 enclosure I stalled for a while, also I rarely/never use my lathe and I didn't need to hurry. As a new owner of a Bambu X1, and having relearned FreeCAD after their 1.0 RC I decided to finish off the build.

The machine is a Optimum TU 2406 V - Vario; it's probably not dissimilar to any other asia-made lathe, however being a vario (variable speed) it had some decent built-in electronics with a 5, and 9v supply on the power board.

I was able to mount the stepper motor below the lead screw, under the fascia using 1:1 ratio gears which I custom printed. I would like to change this for 1:3 pulleys so I get more torque, but the 3d printed gears (with a filed-in keyway) work basically fine for now, however they are noisy due to not running perfectly round.

I originally had a Honeywell DIN rail 5, and 24v power supply in an electrical enclosure below the lathe, however I couldn't source a single cabinet large enough to house the comically-large 24v din rail power supply. I had an inexpensive no-name 24v/3.5A DC supply which came with some CNC kit I never used hanging around. This 24v PSU fits inside the side cover where the belt-drive and is conveniently close to where the main power switch.etc exist.

For the 5v, the machine's built-in tachometer already had 5v, which I tapped and used to power the Arduino.

Attached a bunch of pics, I hope someone gets some benefit from this thread.

Edit to add: the freecad files in the h2 directory seem to be an older version than the stls in the h2 directory; I stumbled over this and modified the printed case directly with a finger sander.

Edit again to add: the hand-drawn labels are actually 3d-printed into the case, but I had such a hard time to model the icons and project the geometry to have neat icons, that I gave up and hand-drew them in the slicer.

[kachurovskiy]

Hi @leehambley, thanks for sharing with us! Hope the little H2 is helpful in your work.

[andreev-]

Hello, please tell me if you turn the spindle for some time, will the degree readings be displayed correctly?

[leehambley]

I don't lose synchronisation here, but there is a reduction between the encoder and the spindle. At higher rpms it does struggle and I think the Stepper is not strong enough

[andreev-]

2024-10-05.17.39.33.mp4

[andreev-]

Why can this happen?

[kachurovskiy]

Try changing https://github.com/kachurovskiy/nanoels/blob/main/h2/h2.ino#L51 DIR_CHANGE_DIFF_MICROS to 0:

#define DIR_CHANGE_DIFF_MICROS (int) 0

This disables the steady-direction logic and always reads encoder direction from the pin. Sometimes disabling it helps with angle problems.

[andreev-]

doesn't help