CNC Laser Engraving 8bit Shades of Grey 445nm

[JJWMACHINECO]

Yea Christopher,

they have quite a cool collection of clipart on there. Here are a few I did from that web site when I first started laser diode engravings on my CNC router. I do have both of my CNC routers setup to either TTL or Analog modulate the laser's power.

Jeff

[JJWMACHINECO]

We tried something new today that has been planned by us now for quite some time. Me and my son 3D spindle engraved a Laurel & Hardy height map greyscale with a 1/32" Ball End Mill with a 1/8" depth. We then laser engraved shades on it with analog modulation from the original image afterwards. We combined the gcode movements generated from Picengrave Pro 4 + Laser using both images to accomplish this. Our Dual 445nm Laser Diode's intersecting focal points follows the spindle engraving's contours up and down to maintain focus on the surface. This is the very first time ever trying to do this.

[Galvonaut]

That is great JJW!

What does the motor at the bottom do?

Keith

[JJWMACHINECO]

Thanks Keith,

The servo motor at the bottom is tied with a timing belt to a US Digital MA3 10bit analog shaft encoder.

One of these.

http://usdigital.com/products/ma3

It takes a 5v analog input (powered by the USB port) and outputs a 0-5v varied analog voltage based on a 0-360 degree rotation to the modulation input on the Flexmod P3. The axis A.0000" to A-.0255" in the gcode gives the 8bit shading in the engraving.

Picengrave Pro 4 + Laser interprets the shades in an image into settable depths for settable axis letters of a Z, A, B or C.

The greyscale height map gcode was generated at a Z.0000" to Z-.1250" based on the shades in that image and then spindle engraved. Then the A.0000" to A-.0255" gcode was generated based on the 8bit shades in original image. The trick was to take the spindle Gcode with the Z axis movements (to follow the contours), and add the LD's varied power gcode A axis movements for the MA3 shaft encoder to vary the power to the to get the 8bit shading onto it.

Here are the two different images we used, except the background on the greyscale heightmap was darkened and the text was removed.

Jeff

[Galvonaut]

Very clever indeed!

Keith

[JJWMACHINECO]

Thanks again Keith,

I also want to mention, we can change the steps for that servo motor in the Motor Tuning in Mach3 to get the overall power we need based on materials and the feedrates we need to engrave at. The MA3 has 10bit resolution (1024 increments) so even if I only use a 0-1.25v (1/4 power)to the P3 modulation, I still get 8bit resolution (256 incremental voltage changes).

Jeff

[Picengraver]

I engraved this yesterday on Baltic birch ply using a 445 LD with analog modulation and a maximum of 1.7 amps. The original size is 9 x 7 inches. Took right at 3 hours.
John Champlain

[JJWMACHINECO]

That is excellent John!!

It looks so real and thanks for sharing it with us.

Jeff

[VDX]

... I was testing my DIY-XY-Galvoscanner with a fiberlaser (only 5W max. due to the small mirrors, so no beam-expanding possible) -- the 'grey' Beethoven was on black Dibond, the 'white' one on the black painted tile from the first image.

This was around 10 minutes scanning time per image ... but can be as fast as 1 minute with proper mirrors and higher pulsing power ...





... and the same fiberlaser on my CNC-mill with around 7Watts -- more would 'explode' the surface, so the fine details will be gone.

This was around 50 minutes ...




Viktor

[swamidog]

those are beautiful. your beam size must be incredibly small.

i made a new lumia enclosure..

... I was testing my DIY-XY-Galvoscanner with a fiberlaser (only 5W max. due to the small mirrors, so no beam-expanding possible) -- the 'grey' Beethoven was on black Dibond, the 'white' one on the black painted tile from the first image.

This was around 10 minutes scanning time per image ... but can be as fast as 1 minute with proper mirrors and higher pulsing power ...





... and the same fiberlaser on my CNC-mill with around 7Watts -- more would 'explode' the surface, so the fine details will be gone.

This was around 50 minutes ...




Viktor