Wine glass etcher

[ggallant571]

Couple of years ago I built an etcher with a rotary table for etching wine glasses. It has a spring loaded chuck that hold the glass in a vertical orientation. The X axis is the rotation and the Y is vertical. Adjusting the Z (distance from the glass) is manual via a slide mechanism. Last week I added a Z leadscrew and motor. I purchased some short distance (200mm) non-contact sensors and would like to follow the contour of the glass.

Current thinking is to run a distance calibration pass and have the host software do the math to compensate for distance and speed.

I can use either Arduino Nano with GRBL or a STM32 with home-brew firmware. Both have pros and cons. Possible implementations:

1. Add code to STM32 base
2. Change to GRBL-2.0 for ARM.
3. Trim unused code from GRBL-1.1 (ie ARCs, info messages, status reports)
4. Switch boards to an ESP32 package.

Switching to GRBL 2.0 for ARM appears to be the preferred long term solution while the ESP32 with radio link sounds interesting. There is an active ESP32 development effort that I am monitoring.

I prefer 3 for quick testing as the distance sensor has examples for Arduino. Any thoughts on how to get 2K code space from GRBL?

[ThothLoki]

Do you happen to have a picture of your design? I have been looking into making a vertical rotary engraver and would like to compare designs.

Love the idea of a Z axis to follow the contour

[ggallant571]

Attached are some pictures. Glad to see you are considering making one. I have the parts (somewhere) to get short distance (less than 200mm) non contact measurements. Supposed to work with clear glass. Also thought about adding two cameras and trying to detect the laser line. Having someone else also making one might just get me motivated.

How is the new baby?

[ThothLoki]

What are you using to turn the glass? i see the nema, but what kind of coupler?

I am thinking of going with a polar design for the "turntable"

[ThothLoki]

Start of my initial design

[ggallant571]

The rotary table was a hard crank intended for a milling machine. I bought it used for $15US. Removed the hand crank. The shaft diameter matched the diameter of the NEMA 17 motor. Used a generic shaft coupler with a vibration cut. Housing between the table and motor is 3D printed although I probably should have used long screws with simple tubes cut to length.

[ggallant571]

The chuck is spring loaded. 3 jaws expand under pressure towards the outside. Easy to mount glass but it means the image needs to be inverted. The range of glass that fits is limited so there is a different one for each style of glass.

I used openscad to model the fixture. It is a "C" like language for making 2d/3d designs. Popular with programmers and electrical engineers, useless to artists and people comfortable manipulating designs by mouse.

[ThothLoki]

I am going to use some toothed bearings and gt2 belt that i pulled from some PTZ cameras.

I need to take some measurements to get things lined up correctly, but most of my equipment is in storage right now while I am moving.

I am decent at editing openscad models, but writing them from scratch.....not so good. I am more a fusion360 user but now that I have moved over to linux, that is hard to use. I need to upgrade my computer to make fusion work on linux (gpu issues).

[ggallant571]

Have you thought about how to coat the glass prior to etching. Diode laser passes thru without generating any heat.

[ThothLoki]

I have used matte black acrylic paint with success (cheap Apple Barrel brand from Walmart). As long as you have an even coat, it works great and washes off with warm water.

I have used black spray paint before but that is a huge pain to remove (need goof off and a lot of time)