Can PhotoVcarve be used to Laser engrave on a CNC Router????

[JJWMACHINECO]

Has anyone successfully converted there CNC router into a Laser engraving machine and used PhotoVcarve to generate the g-code to run in Mach3 to Laser the image?

[olf20]

Below is a link over on the Mach3 forum.
Tweakie has done a wonderful job of developing
his lazer.
Hope this help!!
http://www.machsupport.com/forum/index. ... 444.0.html
olf20 / Bob

[JJWMACHINECO]

Without reading through 58 pages in that thread, did he use PhotoVcarve to generate the g-code? That is really the question I'm asking to this forum. I know converting a CNC router to a Laser engraver can be done using Mach. It even has a plug in for doing it. I have seen that thread before and even read his build on his web site, but could not find anything about PhotoVcarve in the content. It may be there and just may have I missed it.

[JJWMACHINECO]

Looks like I need to answer this question myself. I was able to engrave a picture with a 1.7W Laser Diode on my CNC Router using PhotoVcarve to generate the code. Not perfect, but still experimenting with the settings.

I believe the biggest problem I have right now is the type of wood I'm using. It's cabinet grade plywood.

Laser Engraving

[ssflyer]

Looks like you need a lens to focus your laser...

[JJWMACHINECO]

Looks like you need a lens to focus your laser...

That was not the problem. It does have a focusing lens on the laser, and it was focused down to a .01" diameter beam. Since I'm used to making lithophanes, called out a Ball EM at first, and that is why it looked blurred. These pictures I processed the images in Corel Photopaint and then convert them to black and white. Then I brought them into PhotoVcarve and made my tool a engraving bit with 60 degrees per side and a .01" width tip. Cut at .015 depth which ends up at .0015 depth in the g-code because of blanking out the white in the image. So everywhere a black spot or area is in the picture, the laser would pulse on and then when it retracted, it would shut off and leave the light areas. Pretty much how Laser engraver works, except I used PhotoVcarve to generate a X, Y and Z code. My step over was .01" and I ran at 40 IPM. I pulsed the laser by building a simple circuit that hooked up to my Z axis that sensed the depth changes to turn the the laser diode on and off. The whole circuit is independent and not driven by Mach 3 at all, other then it moving the Z axis to trigger the laser.

Still working on refining all the settings, but Laser engraving with PhotoVcarve on a CNC router running in Mach is possible.

Model

Church

Avanti

Champ

Train

[ssflyer]

Pretty slick - looks like you're definitely getting there!

[dlgabry]

That's cool! Any chance you can post some detail on the laser?
Dave

[JJWMACHINECO]

This is the Laser I used on the latest pictures I posted.

http://www.amazon.com/gp/product/B0044T ... 00_details

It's a 1W and I had to do some modifications to it, like adding some heat sinks and a 3 element UV coated Glass focusing lens. The analog modulation did not work like expected, but I figured out how to pulse it.

The first picture I posted in this thread was done with one of these lasers.

http://www.ebay.com/itm/445nm-Blue-1-75 ... 2183wt_698

It had quit on me about 10 hours into my experimenting. I guess I worked it to hard. Right now it's back to the builder getting a new laser diode installed. One thing I liked about it was the analog modulation worked very good. I was actually getting shading because I was able to vary the power based on depths of cuts instead of pulsing it like I did with the 1W laser. I did not have to convert to black & white before bringing into PhotoVcarve with that laser either.

Right now I have my setup torn apart, upgrading the electronics to control the laser even more precisely and adding some cooling fans. When I get it put back together and running again, I will take some pictures of it and post them.

[JJWMACHINECO]

Got it back up and running again with cooling fans and a new high speed switching circuit. The circuit works great and is more responsive (on/off) to the Z axis movement then my first one. I can really see an improvement in the detail. PhotoVcarve actually previews the image exactly like it will be generated by the Laser. Here are some pictures of the latest image I lased and my setup on my CNC router. The picture was 9.6"X12" and took 4 hours and 27 minutes to complete. Not bad for only a 1W laser diode and I can't wait until I get my 1.7W laser back. I really enjoy doing laser engraving on my CNC router. I don't have to listen to the screaming sound of my 45,000 RPM spindle anymore and no more Corian dust or wood dust everywhere. However, I do have to wear 455nm laser filtering glasses and deal with the smell of burnt wood.

[dlgabry]

I've got to add this toy to my wishlist! Couple of questions.....
Was this done on bare wood, or was some sort of coating applied first?
The laser picture looks like there's a microswitch operated by the stud on the Z carriage?
I'm curous about the circuit you used to modulate the laser.
I think you said the feed rate you used was 40IPM?
Dave

[jimwill2]

Very impressive! Thanks for sharing details with us.

[JJWMACHINECO]

I've got to add this toy to my wishlist! Couple of questions.....
Was this done on bare wood, or was some sort of coating applied first?
The laser picture looks like there's a microswitch operated by the stud on the Z carriage?
I'm curous about the circuit you used to modulate the laser.
I think you said the feed rate you used was 40IPM?
Dave

The wood is unfinished birch cabinet grade plywood.

The electrical components were bought from RadioShack. Selectable 300ma power supply from 1.5,3,4.5,6,7.5,9 and 12VDC. A LM317T adjustable voltage regulator circuit. Schematic of circuit is on the package of the chip. This will give you variable voltage based on input voltage, but will not go down to zero volts, therefore you have to put a 5V 7805 on the output so it will give you 0-5V or lower based on your input.

Potentiometer is attached to Z axis through a 2 disk Huco slip clutch to keep over travel of Z axis from damaging potentiometer. The stud is to keep the board I made from rotating and has rubber between the stud and the board to allow for any slight wobbling of the potentiometer shaft. With this board, it works great on a laser that has Analog or TTL 0-5V Modulation that works properly, it needs an input voltage of 7.5VDC from the power supply which will give you 0-4.8VDC on the output. You move the Z axis to focus the laser off the material. I found that a black anodized surface works best for that because it does not reflect the beam and does not burn the surface while your adjusting the Z axis. I use the analog voltage meter to calibrate Z0.0" You just loosen the slip clutch and rotate the potentiometer until it just reads 0 Volts and then tighten the slip clutch back up.

I made a new profile in Mach for the laser. You have the go into motor tuning setup and change the Steps Per for the Z axis so the volts on the meter will go from 0-4.8V with the Z axis moving from Z0. to Z-.005". This movement is not enough to bring the laser out of focus. G-Code from PhotoVcarve then will vary the power from 0 to full power and give you shading and I used a Z retract of +.002" to insure the laser goes off completely when it retracts. When I get that laser back, I still need to refine the settings some more to get the image to come out perfect. Feed rates are a big factor with the power of the laser also. I found that 40-50IPM works best with my 1W-1.7W lasers. If you want it darker, slow the feed rate down, but of course it takes longer.

The problem I had with the analog modulation on the 1W laser was with no voltage to the connections, the laser would come on. I found that if I touched the the positive and negative wire together, the laser would go off. I started with a 5V SPDT relay so when Z went into negative, the laser would come on and when it would go positive on Z, it would go off. It worked, but the problem with a relay is the drop in voltage is not the same as the drop out voltage, therefore it was effecting the resolution of the lasered image. A diode across the positive and negative of the relay coil helped collapse the coil voltage quicker, but it was not enough. The relay package states it's good for 10,000,000 cycles, but I switched it on on/off 88,525 times in the last image I posted alone, so I needed something more reliable and switches on/off as close as possible to the same voltage. I then made a new board with a Triac to do the switching. It switched on/off within .0002" of Z movement instead of the .001” I was getting with the relay. The gate on the Triac needs 3V maximum voltage to switch, so changing my power supply to 6V and readjusting the motor tuning steps, I got 2.5V at a negative .0015” on Z.

Giving a value of .015” of cut depth and a retract of Z+.0015” in PhotoVcarve and making all white of a black and white image transparent, will generate a code that makes the cut deptch Z-.0015” where black is and will retract to Z+.0015” where white is. No special PP is used either.

Very impressive! Thanks for sharing details with us.

Thanks for the compliment Jim. It took some time to figure all this out and allot of help from my son.

I made this one today just for fun.

Jeff

[dlgabry]

Jeff, nice job and thanks very much for the detailed description!!! Looks like it's time for me to beging foraging through my junk box(es) to see what I can use
Dave

[JJWMACHINECO]

Jeff, nice job and thanks very much for the detailed description!!! Looks like it's time for me to beging foraging through my junk box(es) to see what I can use
Dave

Thanks Dave. If you get something put together and start lasering, please post some pictures.

I have been reading that Basswood is good for woodburning, so I went to my local craft store and found some. Unfortunately the largest piece they had was 24" long by 4" wide 1/8" thick so I bought a couple. I decided to do a couple of tests at the same time. 1st is reliability of my laser switching circuit laser and 2nd, exactly how good of a resolution can I get with this setup and 3rd, see how well the Basswood laser engraves. I found a panoramic photo that was taken in 1926 and was real busy with allot of people in it that would fit on my Basswood piece I just purchased. I generated the code to do crosshatch this time and it ran 7 hours 41 minutes continuous with 358,589 lines of code and it turned the laser on and off by retracting 191,785 times by checking it with my text editor.

My laser printer for wood with the PhotoVcarve driver passed with flying colors. The switching circuit and laser had no failures what so ever and the resolution was as good as the original photo. I did not notice any difference using the Basswood compared to the Birch plywood. I think I will try a laser engraving using my 4th axis next.