015 / .020 deep engraving in 4140 - What kind of laser does it take ?

[MassiveTool]

.015 / .020 deep engraving in 4140 - What kind of laser does it take ?

Not sure if this is the right place to ask this but if anyone could help me that would be great.

What I need to do is Laser Engrave .015 / .020 deep in 4140 carbon steel.

I have an old 3 Axis CNC vertical machining center with a true programmable 4th axis rotary that I want to retrofit / replace the spindle with a laser on the “Z” axis and use it to engrave.

Now this seems pretty straightforward to me, remove the spindle – replace it with a laser. The laser cuts instead of a cutter in a spindle the “X” “Y” and “A” provide precision movement with the use of standard “G” code programming.

The “Z” axis can be moved for focus as needed.

But I am hung up on 2 details. (Probably because I don’t know a thing about lasers)

1) What would I need as far as laser power to reliably engrave .015 / .020 deep in carbon steel ?
2) How will I interface the “firing” on and off of the laser with the CNC so I can engrave and everything is not connected by a burn line. I would like to do this with an “M” code much like spindle on /off (M3)-(M5) unless there is a better way of course.

IE:
1)Laser on- engrave the letter “A”
2)laser off
3)Move to new position
4)Laser on- engrave the letter “B”
5)laser off
6)Move to new position

and so on.

If anyone here could point me in the right direction I would greatly appreciate it.

Also, does anyone know of a unit that is commercially available that I could just blot on ? This is an option for me too.

Thanks in advance.
MassiveTool

[davereagan]

Why take the spindle out? Just mount the laser a little below it and save a bunch of time and the machine can still cut later if you want. You could just unplug the coolant pump and look for the coolant relay. Have someone turn M8 on and off while you are right at the control panel with your ears close to hear which one it is. You can run a circuit through that relay pretty easily for the laser if it is just a simple on/off.

[zax15uk]

I would suggest a diode laser system, it would be much easier to integrate onto the Z-assembly and capable of etching alloy steel.

Low power Nd:YAG or a fiber laser would work well.

Check out www.laserphotonics.com or just do a search for the above laser technology.

Obviously bolting on a laser has significant safety concerns, you will need to consider shielding and other safety precautions. I modified the dust (vacuum) extractor head to work as a laser shield, and wear protective glasses when around the machine.

Zax.

[MassiveTool]

Originally Posted by zax15uk I would suggest a diode laser system, it would be much easier to integrate onto the Z-assembly and capable of etching alloy steel. Low power Nd:YAG or a fiber laser would work well. Check out www.laserphotonics.com or just do a search for the above laser technology. Obviously bolting on a laser has significant safety concerns, you will need to consider shielding and other safety precautions. I modified the dust (vacuum) extractor head to work as a laser shield, and wear protective glasses when around the machine. Zax.

Hey Zax

Thanks for the input and the link.

I think this is a step in the right direction for my project. I’m going to contact this company see if I can set something up for a meeting.

Living in the North East where even in July the temperature can’t seem to get past 70degrees and if it does it’s raining I’m always looking for a good reason to go to Florida anyway.

Thanks again !