@Ryan I have been testing this program the Viktor made and posted on Thingiverse. I have some test results.
@viktorglekler I really like the program. I love the clean interface, the idea of keeping it simple but functional. I also like the way you made it so it doesn’t have to do as many unnecessary moves. Creative solution that took time and effort to implement I am sure. As a former programmer I commend you for a job well done.
Now if I may say the bad news. It doesn’t work very well for an MPCNC. The MPCNC has a lot of weight to move around. So it needs to take extra time and distance to get up to speed. Smaller laser engraver machines can accelerate faster so I think this program can work very well for them.
In some of my testing I used this horse image as an example. In my first attempt to use this program I set the speed to 600mm/min (or 10mm/s). I have tested this speed with my laser previously and I know it is a good speed to use that will produce the most even results. That should make the darkest spots at full power burn a dark brown. In the file created by the app it started with the legs. I saw the laser move directly to the first hoof then go back and forth left to right for a few lines then jump far to the right to start on the next hoof. It went back and forth left to right for a few lines then returned to the first hoof for a few lines. The problem is the machine at full acceleration couldn’t get up to full speed of 600 mm/m. So it was burning much darker than it should have. I let the test run for a while and the larger partial horse was the result. Way too dark.
[attachment file=83954]
It should look closer to this. This was made using a different program on the same machine, same wood material with same power settings. The only difference is speed. My previous burn used a constant speed close to 10 mm/s that passed the entire length of X one layer at a time.
I decided to end that test early and test again increasing the speed in the app to see if it made any difference. I changed it from 600 mm/m to 1800 mm/m. The result is pictured in the first image. The partial legs. They are just as dark as the first test at 600 mm/m. So I know for sure the top speed doesn’t matter if the acceleration is so slow that we will never reach that top speed.
I thought about running a test using lower power settings on the laser but I realized that would be like trying to hit a moving target. Sure, I could try a few combinations to eventually get the horse legs light enough to be correct but then the body of the horse would be way to light colored. So I gave up on that idea before I even tried it.
I decided to test an image that doesn’t have any “Skipped” space. aka every pixel is grey to black. No white pixels to get skipped. I was hoping to discover that the outer edges would be darker but the center of the image would be the perfect grey. (Unfortunately I left the travel speeds set so high that my machine skipped some steps so the X axes shifted a little. So don’t judge that part.) But if you look closely at this next image you will see that it actually worked. The far left and far right sides of this 80 mm square burn are darker where the machine is speeding up and slowing down. It looks like it is about 5 mm on either side that is darker than it should be but the rest is pretty good.
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In conclusion. I love this app and I am really sad that it won’t work for the MPCNC for most images and logos etc. I love the idea of eliminating wasted movement but it is that movement that keeps the constant speed necessary for a clean image burn.
@viktorglekler If you are willing to make a few changes for us MPCNC users could I please request the following:
- Have an option for full rectangle movement to minimize the accelerations.
- Or a more advanced option would be to have a setting for an acceleration buffer. A distance that the machine could use to travel beyond the burned image to speed up and slow down so the laser can be moving at the desired speed by the time it is supposed to turn on.
- PLEASE add the laser off command to the end of the gcode file. If you look at my third picture you will see a large burn hole near the corner of the test image where it finished the file and then left the laser on. This happened on a few other test runs I made as well. very dangerous. I was near the machine and heard it stop but I took a minute before I approached it. That minute could have started a fire and would have if I didn't have an air assist fan blowing on it.
- Please replace the feedrate and travel speed sliders with text boxes. It is very difficult to get close to the numbers I wanted with a mouse. It was even harder with a laptop touchpad. I gave up and just held the CTRL key and used the arrow keys to get to the numbers I wanted. Sorry to say but it was frustrating to make a small movement and be 1,000 over my target number.
- Please add Gcode to the beginning of the file that will turn the laser on with a power level of 5 (of 255) so it is visible. Then draw a rectangle around the area that the machine will go when it is cutting/burning. This way the user can see if they have the right size and alignment before the burning begins.
- Please add the ability to set the origin as the center of the image. This is a really cool feature that allows the user to be able to burn a logo or decal into the center of something.
- Please add the ability to perform a test burn that will compare speed vs Power level. I build a gcode script that does this but it would be better if it could be made into a program with parameters and settings so the user could control the max and min speed & power. Something like this would be helpful for users to get to know how their machine works and what settings would be best for them to use in the app.
