I am making a birdhouse at the request of my very young grandson. I am using Birch ply which is 3mm thick. It was lightly sanded with 240 grit to make a nice surface to receive the image. LightBurn laser driving software was used for controlling my 4.2W JTech blue diode laser (445NM). The laser has a high resolution lens and it focusses sharply at precisely 3.175mm (1/8") away from the workpiece.
The traversal speed was set to 1000mm per minute (39.37 inches) and the power was set to 25%. The .jpeg image was processed in Affinity Photo to make the background transparent and the file was exported as a .png file, which can carry an alpha channel (transparency). The image processing in LightBurn used a dithering process known as Jarvis and the burn occupied around 90 minutes. workpiece size is A5. This is 148 x 210mm and approximates to 6 x 8" for our north American cousins.
The relatively quick traversal speed was applied so that the laser did not have time to scorch the wood nor did it produce any smoke damage. The video linked shows that no burning, scorching or smoke was present during this engraving. What you see is the un-retouched image demonstrating how the workpiece came off the CNC machine after engraving with the laser. Any and all comments are welcome.
EDIT:To add short video link and a little more text.
Thank you for your kind comment, Michael. The traversal speed really helped the timing. Upping the speed and the power could have been done but when you can feel and hear the CNC machine every time it changes direction, the slower speed helps to smooth the pathway.
Besides which, the LightBurn software allows for an over movement (I set mine to plus 2.5%) so that at the end of each travel direction, the laser switches off as it reaches the end of the image. It then continues moving in the same direction with the laser off so that it slows down gently. When it returns, it accelerates in that 2.5% window and reaches full speed where the laser switches on again just as it reaches the image boundary. The end result is an even burn at the edges of the image.
I don’t know anything about V Carve’s laser toolpath creation. I do know that LightBurn starts from a somewhat different place. Instead of one tool that can do many things, the LightBurn approach is to making a single tool that controls lasers and can work with any type of laser or 8bit CNC controller. It is rational in use and easy to learn.
I don’t know if it supports the 32bit Duet controller yet. It can drive diode, CO2 and Fibre lasers and what it does is dedicated to laser driving. It has a lot of tricks up its software sleeves and I have always found it to very well considered and it is updated regularly.
