Engraving Images Using TTL (pulsing)
Some materials and images do not engrave very well using varied intensity. Wood that has allot of grains or is too dark to get decent shaded results, must be done the old fashion way that the Commercial CO2 laser engraving machines still do today. They have to convert the image to 1bit Black and White and then pulse the laser with dots to get the allusion of shades.
We picked up a cheap Cigar Box at a yard sale and the wood is a little dark, so we are going to explain how to TTL engrave an image on it with the EmBlaser.
First to insure there are only Black & White in the image, we needed to Dither it first. In the PEP5 image editor there are 11 different Dithering Algorithms to choose from. PicEdit Lite also has this Dithering feature. We are going to use Atkinson on a Clipart image that we decided to use on this Cigar Box.
After re-sizing the image and Dithering it, we loaded it into PEP5 to generate the gcode. Since we only want zero power or full power for pulsing, we set Min at S0 and Max at S255. If the image is not 1bit, the Gcode PicEngrave Pro 5 or PicLaser Lite generates will have power variations in between the S0 and S255 values, so the image Dithering process is very important. We don't know what this wood is or how it will burn, so we set the Feed Rate at 60IPM (1524mm/min).
After starting this engraving I realized, we could have increased the the Feed Rate more, or lowered the Max power as it's burning the image a little dark. You can experiment with the different Dithering Algorithms, max power setting and Feed Rate to achieve the desired result on the different materials you choose.
The Gcode file was 1,466,683 lines long and we streamed it to the EmBlaser with PicSender.