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Engraving Text

Hey Dave,

While waiting for Will, I think I can answer the second question for you.

When you are doing laser engraving, your laser is the cutting tool.  Simply zero out the X and Y axis where you want them as if the cutting laser was the router tool bit.  From what I have read, most guys use a red dot pointer laser that is synced up with the cutting laser.  Both the red dot and the cutting laser are pointing at the same spot.  In other words, if you have a laser engraving job you want to do, act as if the router is not even there.

You will want to insure your cutting laser is mounted straight up and down.  The red dot laser can come in at an angle.  BUT, the trick here is you need to know what distance the cutting laser head is from the surface you want engraved to insure you got the red dot just right.  In other words, if your red dot laser is coming in at a slight angle, the two lasers points can be in different locations on your surface depending on the Z axis position.  There is only one correct (Z axis) position that both your red dot laser and cutting laser are going to be pointing at the same spot on your surface.  Whatever that measurement is, you will always have to make sure your Z axis is set to that before trying to line up the cutting laser with the red dot laser.  I hope that makes sense.

 

Dave, I'm not sure what you mean by "can't get the registration to work".

To answer your questions:
1: it took me a while to work this out myself, I couldn't find a specific 'how to' for my laser, I interpolated several online sources, and got lucky.

My control board has a power plug, a three wire socket, and a two wire socket.  Using the two wire socket I connected one wire to the spindle control output on my CNC control module, and the other wire grounded on the gantry (my older control module doesn't have laser output, and I use a separate VFD for my spindle motor).  I use G-Code 'M3' and 'M5' commands to turn the laser ON & Off and control percentage power using 'S… '.

2: I'm not sure how you would align your laser to your datum.   If they swap out cleanly and easily you could try something similar to what I did:

With an engraving bit in the spindle motor I drilled a fine hole in a piece of wood fixed to my table.  Set X and Y to 0.00 at that point.  Turned on my laser at low power (just enough to see a dot, <5%)  and moved the dot to the middle of the hole.  Turned off the laser and read the X&Y values which gave me the offset of my laser to my spindle motor.  This way I can use the spindle motor with a probe and touch plates to define a spot that is half the probe plus the offset X & Y from the datum.

Having done that, I found that a simpler method of for each and every job, aligning the laser with my datum is much easier and more practical: I turn on the laser at low power , move the dot to the datum by eye, set X & Y to 0.00.

Thanks Will,

I finally got mine working and engraving. Surprisingly a 2W laser is more powerful than expected. I'm engraving at 3% and 175 inches/min (75 mm/sec).

As I destroyed my Lear throttle, I'm building my own modifying Saitek throttles. Not exact but functional. I engraved the cover. When I finish I'll post.

Have you considered using LaserGRBL? I'm trying to drive my CNC next week with it. Very nice product for free. It will drive your CNC and laser directly thru USB.


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