CNC Laser Engraving 8bit Shades of Grey 445nm

[JJWMACHINECO]

Check out our new 445nm laser diode engraving machine. First one we did not build our self. Well, some assembly was required.

Gcode was generated with our newly released grbl compatible PicEngrave Pro 5.

[JJWMACHINECO]

We are getting very impressive results engraving photos with our new J-Techphotonics 445nm 2.8W Shapeoko laser kit with there G2 lens.

Arduino UNO GRBL controller with PWM to vary the intensity on Pin 11. The firmware allows you to switch to Z axis control with a $L0 command to adjust focal height, then PWM laser control with a $L1 command to laser engrave photos.

the LaserMode grbl hex file can be downloaded here: http://www.picengrave.com/downloads/...-Andy-grbl.zip

If your looking for a complete laser diode cutting & engraving solution for your CNC machine, we recommend a J-Tech Laser System. The J-Tech comes standard with a high quality G2 lens which in our testing engraves photos very impressively. http://jtechphotonics.com/

Gcode generated with PicEngrave Pro 5 for this engraving.

[swamidog]

We are getting very impressive results engraving photos with our new J-Techphotonics 445nm 2.8W Shapeoko laser kit with there G2 lens.

Arduino UNO GRBL controller with PWM to vary the intensity on Pin 11. The firmware allows you to switch to Z axis control with a $L0 command to adjust focal height, then PWM laser control with a $L1 command to laser engrave photos.

the LaserMode grbl hex file can be downloaded here: http://www.picengrave.com/downloads/...-Andy-grbl.zip

Gcode generated with PicEngrave Pro 5.

Attachment 46228

that is beautiful. i'm getting some really profound results with high dpi dithering on my c02 system, but i could certainly get nicer results if i could do actual greyscale.

[JJWMACHINECO]

Thanks Swami,

Will your controller except a PWM signal to change the power of your laser? If so, there may be a way to do it with an Arduino Uno & the LaserMode grbl. It takes X,Y & Z0-Z255 commands and outputs PWM signal at 1khz between 0-5v.

There is another discussion of another PWM grbl on Github now for controlling a laser's power and it uses S0-S255 commands. They are real close on getting it to work properly. https://github.com/grbl/grbl/issues/...mment-72577742

Jeff

[JJWMACHINECO]

Here are two photo engravings we done from the same edited image on two different CNC laser engraving machines we have.

This one was done on our Shapeoko 2 with the J-Tech laser system using there G2 lens. We used the PWM Z commands Z10 min Z255 max with the LaserMode grbl.



The second one was done on our EmBlaser (aka LazerBlade) with a 3 element glass lens. We used the PWM commands S10 min S255 max with it's grbl.



The spot on Albert's chin in the EmBlaser engraving is not a wart or mole. It was a knot in the Poplar wood we used.

[swamidog]

Thanks Swami,

Will your controller except a PWM signal to change the power of your laser? If so, there may be a way to do it with an Arduino Uno & the LaserMode grbl. It takes X,Y & Z0-Z255 commands and outputs PWM signal at 1khz between 0-5v.[/url]

Jeff

the current controller i use won't, but there is rumored to be an update that will allow for it. even without it, i'm quite quite good results with 600 dpi dithering on slate tile.

[JJWMACHINECO]

the current controller i use won't, but there is rumored to be an update that will allow for it. even without it, i'm quite quite good results with 600 dpi dithering on slate tile.

Theoretically, when using PWM we are just pulsing the LD very fast. The DPI is so high, they just blend together into a solid burn line. You can see the pulsing glare lines in our videos. Our analog modulation LD engraving machines glare lines are solid (no Pulsing).

[RickTown]

Jeff,

I really like what you're doing.

Couple of questions...
With using the shaft encoder, It seems like there's a possibility of delayed laser shoots and turn-offs due to the mechanical nature of the modulation. At least perhaps during high speed burning over an already routed picture. I'm curious if you've seen any visible artifacts from the "less than instant" modulation.

Also, if you're engraving something like aluminum that doesn't color like wood, does the grayscale show up as well as dithering?

Thanks,
Rick

[JJWMACHINECO]

Hi Rick,

There is no apparent delay with the modulation. All three Axis movements are synchronized together on the same line of Gcode in the file. We also set all the accels for the steppers or servo motors the same and with a 3.33-1 ratio from the motor to the encoder, it's very responsive and quick rotational movements. The US Digital MA3 shaft encoder's Position Sampling Rate is 2.61 Khz. I'm not sure what the specs are with the Flexmod's response time from the modulation.

http://cdn2.usdigital.com/assets/dat...48170413905335

The highest Wattage laser diode engraver we build is 4.5W on a servo CNC router and we are able to engrave photos on Birch Ply at blended feedrate on 225IPM with Mach3. It's not powerful enough to engrave on aluminum.

We have 8bit engraved on Artist Canvas, Leather, back of mirrors and of-course wood. It just takes some experimenting with feeds and power levels for the different materials.

Jeff

[RickTown]

That's good to hear. I guess the example I had in mind was let's say you're engraving horizontally and burning a very fine, very dark vertical line, I was wondering if the line would be sharp or if there would be some gradient on both sides from the encoder spinning up or down.

If not then this sounds like the perfect solution to make a laser compatible with basically any CNC software.

It looks like it's time to order some parts and heat up the ol' soldering iron...

Thanks.