Raster Etching on Goldfinger Vector vs Raster G-Code works in Vector mode – laser is directed from Point A to Point B via a.
Download ReportTranscript Raster Etching on Goldfinger Vector vs Raster G-Code works in Vector mode – laser is directed from Point A to Point B via a.
Raster Etching on Goldfinger Vector vs Raster G-Code works in Vector mode – laser is directed from Point A to Point B via a path (line, arc, spline) Raster etching scans across line by line, turning the laser on and off as it scans back and forth (think bi-directional Dot Matrix Printer) Etching Parameters An Image file Image does not have to be resized first Preprocessing may not need to be performed – Goldfinger will automatically convert image to grayscale Position for upper left corner of image on the laser workbed (x, y)) Width and height of resulting etch (w, h) Units of distance per “pixel” – think 1/DPI (xscangap, yscangap) Keep it proportional to the original image or else be prepared for stretching! For mm, 25.4mm = 1 inch Overscan (overscan) Distance in x direction to scan past the image on each side Needed to allow laser gantry to accelerate to full speed before etching Etching Parameters Visualized x,y w h Overscan (exaggerated) Overscan (exaggerated) Magic G-Code Raster function is called by calling the O145 script from a G-Code file Script was written for Buildlog 2.x laser cutter Uses Python Image Library for image processing and ties into LinuxCNC HAL Script moves to (x-overscan,y) location and scans back and forth while taking input from image file on when to turn laser off and on O145 call [777] [8] [190] [100] [182] [0.085] ( pic x y w h [0.423] [8] xscangap yscangap overscan ) Parameter sanity Image x position must be >= the overscan value Image y position must be >= the image height Increasing the pixel density in y-axis (decreasing yscangap) == more lines to scan == longer to etch the image Increasing the pixel density in x-axis (decreasing xscangap) does not impact scan time Overscan of 8mm appears to work well Lower values may work as well, I have not experimented yet to see how low we can go Too low and the edges of the image will be darker than the middle due to the laser spending more time there Higher values of course add time so finding the minimum acceptable value will be useful DPI to scangap (for mm mode) == 25.4/DPI 300 DPI == 25.4/300 == 0.085 60 DPI == 25.4/60 == 0.423 Misc Notes I have so far only attempted plywood using PWM = 0.16 and Feedrate of 3000mm/min with good results Other materials will need adjustments to the power level and possibly the feedrate Raster etching function is useable within a vector cutting G-Code file as well but parameters like M63/M65/Spindle Speed need to be controlled before and after the raster function I would first try to adjust just power level as slower feedrates may drastically increase etching time Alternately, a vector file can be sent to the cutter after the raster file (prior to moving the work piece) Lower resolution needs more power Entire G-Code File % M63 P0 (Turn off synchronized motion) M65 P0 (Turn off digital output immediately) G00 Z0.000001 (Z-Magic output off) G21 (All units in mm) M68 E0 Q0.16 (Set the laser to fire at 0.16) F3000 (Feedrate 3000 mm/minute) M3 (Enable the spindle – Laser can fire) S0.000001 (Set the spindle to the slowest rate that LinuxCNC sees as being on) O145 call [777] [8] [190] [100] [182] [0.085] ( pic x y w h [8] xscangap yscangap overscan ) M5 (Disable the spindle – Laser cannot fire) % [0.423] The easy way Things to try Balsa wood (deeper etching) In theory, one could send multiple raster “layer” images to generate multiple depths of etching Scroll Saw Art Toast Acrylic Glass (Try 0.20 or so for PWM, maybe, I wouldn’t know) Resources / References https://knoxmakers.org/wiki/Raster_Engraving http://goldfinger.kmlan/raster.php https://www.youtube.com/watch?v=WEVeHWpXeF4 http://www.artifacturestudios.com/how-to-understand-thedifference-between-raster-and-vector-graphics/