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Topics - ggallant571

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1
General Discussion / GRBL problem
« on: December 08, 2020, 07:38:51 PM »
I have grbl-1.1f installed on a couple of machines and today isolated a problem with the firmware. If a limit switch is asserted when  the CPU comes out of reset, the HOME function does not work. I ended up manually moving the rail and resetting the CPU.

2
General Discussion / Etching ceramic tile
« on: November 30, 2020, 04:43:39 PM »
I've been have pretty good results etching white ceramic tile by painting with black or dark green high temperature paint. When it works, the ceramic surface is slightly fractured and the paint gets firmly embedded. Scratch resistant, dishwasher safe.

The downside is thin lines etched in parallel to the burn path are nice while those perpendicular are not so nice. Especially under a microscope. If the lines are 3 or more pixels wide there is no problem.

Getting the speed/power recipe correct is critical. Being off by 50mm/min can make a huge difference. Tried slowing the speed for single width pixels but it wasn't very helpful (works nice on wood). Wondering if a 45 degree burn would be better.


3
General Discussion / Odd behavior at low power
« on: October 19, 2020, 12:24:35 PM »
I am etching some material that reacts to the laser at low power. My problem is the first pixel on every line, from both directions, is much darker than the rest of the line. I am not sure of the exact length but it looks like single pixel under the microscope.

4
General Discussion / Etching Ceramic Tile
« on: September 25, 2020, 05:56:09 PM »
I have been experimenting etching ceramic tile with a 2.5W diode laser. Nicky Norton has published on Facebook a nice tutorial along with about 100 great images using white paint on white tile. I have 100% failure but using dark paints has been very promising. Attached was with dark green high temperature paint. After etching washed with acetone and dish detergent. Getting the right paint layer depth is critical. So far, success outnumbers failures. Just bought a box of 92 100x100mm tiles and 4 of these 200x100mm for under $15US. Suspect the cost of paint and cleaners cost more than the tile.

Should you give it a try it is very important to wash the tiles prior to painting.

5
General Discussion / Odd Homing Behavior
« on: August 12, 2020, 07:38:24 PM »
I have a core-xy etcher that has been in use for over two years. Recently started having odd behavior when performing homing operations. About 50% of the time it works as expected. Triggers the limit switch on the Y rail, backs off a bit, drives the carriage along the X rail till the limit switch trips, and backs off 5 mm. The other 50% it does a small surge and stops wait an "error<-1>" message on the console.

Firmware is grbl-1.1f.

Can replicate in a terminal emulator by typing $h.



6
General Discussion / GRBL G00 and laser
« on: July 02, 2020, 10:49:14 AM »
I thought that the laser isalways  turned OFF during G00 motions.

7
General Discussion / Scratch paper
« on: June 30, 2020, 07:30:18 PM »
I have been experimenting with burning images in scratch paper. Scratch paper consists of 4 layers, paper, clay, crayon, ink. Normal use is using a scratch tool remove the lop layer of India Ink exposing the colored layer below. Some users on a Facebook page tried using a laser with fairly good results. I think most use a CO2 at high speed and very low power at a 600 DPI resolution.

I tried with a 2.5W diode laser. The trick is to apply enough energy to burn the ink but not touch the crayon. Got acceptable results when I filtered the black pixels to be 1 out of 4 with a speed of approx 3400mm/min and a power of 90 out of 255 on the thinner brand of paper and a power of 150 on the thicker paper (ink seems to be different).

I suspect that part of the problem is I do all burns at a 0.1mm resolution and that the grid scheme effectively changed that to something close to 0.20 in X and 0.14 in Y. I also means that the laser is only driven On for one pixel (0.1mm). I need to do the math and tests but suspect that the laser is not fully ON before being turned OFF. Question is how to quantify and control that process. What test patterns and materials can be used? Is there a difference between running that laser as a raster and firing while in motion vs coming to a stop and pulsing the laser.

There are two goals in this quest. First is to making the underlying colors more vivid. Second is to learn how mathematical transforms (filters) affect the end result. After laser etching for almost 4 years (mostly slate & 2 tone wood) I feel like an absolute beginner. I don't know the art, math, or physics necessary to get repeatable results. If there is any interest we could create a category here specific to this technique.

I purchased 4 different brands/type of paper. Have only experimented with two. Both were "rainbow" crayon layer. Attached is picture of first success. BTW - looks much better than the picture


8
T2 Engraving / T2 Language
« on: May 26, 2020, 03:48:09 PM »
Zax - would you mind stating what language you developed T2 in. We have an Arduino Mega Greenhouse controller that has a local 4x20 display and configuration/logging via SD card. Would like to add wifi and a GUI for remote control and display of operating conditions. Nothing to to with Lasers but we started with C# on Visual Studio and the learning curve is steep.

9
General Discussion / Odd Behavior
« on: March 29, 2020, 06:19:45 PM »
My 2.5W diode had been performing poorly. Replaced it with a 3.5W that has a much larger forcus point. Been doing mostly cutting so switched back to 2.5W. Todaty I wanted to do an etch and did the test burns on cardboard. Came out horrible. Any horizontal lines that were less than 3 pixels wide wide either very faded on just not there. Put the 3.5 back in and repeated test. Again not very good. Did some test cutting and both diodes behaved as expected. Did some test etching and both misbehaved.

This is with grbl-1.1f with laser mode enabled. Looked at the gcode and the speeds are not changing when doing the horizontal line so I don't think it is related to acceleration. 

Wondering if grbl with laser mode on always mucks with the laser power.

Current thoungths:

1. Disable laser mode.
2. Change the gcode generator such that it only emits a Fxxx on a change in speed.
3. Lower both the power and the speed.

Any other?????????????

Attached is the image that I am trying to etch. If anyone does etch please post you results. On my fixture I am burning at a 0.1mm resolution so this image is 110x110mm.

10
General Discussion / Replacement Eleksmaker 2.5W modules
« on: March 11, 2020, 08:17:23 AM »
My 2.5W has been slowly degrading, OK for etching, poor for cutting. Twice have swapped in a 3.5W and gone back. Both are Eleksmaker with the blue heatsink. Yesterday I measured the kerf on the 3.3w and the best I can focus to is 0.9mm measured on a 20mm square pattern. Tried swapping the focus lenses between the 2.5 and 3.5 modules and it got worse.

Went to eleksmaker.com to purchase another 2.5W module. They no longer have a store but forward to https:eleksmaker.alieexpress.com. This site does not respond. I do not want  a "fake" clone with exaggerated specs!!!!! Where to purchase?

On a related issue, does anyone have experience with different lenses. I have some that I purchased about 3 years ago and they all are worthless.



11
Projects / Wine glass etcher
« on: February 21, 2020, 06:55:11 AM »
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?



12
General Discussion / Nano bootloader
« on: February 13, 2020, 07:15:14 PM »
I have not done any firmware updates on factory fresh Nano's for at least 2 years. Got some cheap Nano's cause I fried one and now having problems loading grbl-1.1f. Suspect it has the older large bootloader. It connects at 57600, does the write, read, and fails on the verify at address 0c7F00. What is required to get a more modern (small/faster) version?

The simple Blink test from the Arduino environment works.

 

13
General Discussion / Ideal laser distance
« on: February 04, 2020, 02:56:09 PM »
After three years of playing with diode lasers I am finally getting around to determining what is the ideal distance from lens to work. I know it depends on the lens. Originally I was at 150mm, went to 120 for a long time, currently at 100mm. My 2.5W has been under-performing lately and getting a good focal point is difficult.

14
General Discussion / PNG to SVG utility
« on: January 13, 2020, 09:52:10 AM »
I have been slooooooowly developing a utility to convert raster PNG images to vector SVG. I want to combine outline cutting, inside shape cutting, and etching into a single process. The end goal is to make shadowbox style multi-layered cuts with minimal manual intervention.

I am looking for a relatively complex design that you own and would like converted. Currently at the "beta" level so it may take a while to tweek the utility before it comes back to you. The attached image shows a png download (upper) and the resulting cut (lower) in 0.5mm maple veneer. Spent about two hours cleaning up the original image including converting the image to just black & white (a step that the utility should eventually not be required).

15
General Discussion / Early BCL documentation
« on: January 13, 2020, 09:29:03 AM »
I have been advising new members to read Ralph's excellent document on calibrating your diode laser using BCL. After searching and some PM's with Ralph it appears I must have been mistaken. He does have a series of video tutorials that cover the topics but not a document.

However, I recall printing one. This was during the early days of BCL development when a number of us volunteered to be  beta testers. As I normally don't use Windows on my home systems, I setup 2 dual boot laptops, one with Windows 7 and another with 10. Those environments are long gone.  If anyone has the docs please post or email.

In the meantime, watch the videos!!!.

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