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Author Topic: How do i setup Mach3 to control a laser with TTL input?  (Read 36089 times)

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How do i setup Mach3 to control a laser with TTL input?
« on: March 20, 2009, 08:50:59 PM »
HI

I'll like to be able to control a small laser diode on my router via Mach3
For engraving letters on balsawood

I have seen some laser controllers that use TTL input on Ebay

How do I setup Mach3 to turn on/off the laser at the right moment?
As i understand it there is a small startup time for the laser before it's ready to "burn"
Is it possible to let Mach3 handle it all, or do i need to change something in my postprocessor aswell?

regards Borge

Offline Chaoticone

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Re: How do i setup Mach3 to control a laser with TTL input?
« Reply #1 on: March 20, 2009, 09:38:11 PM »
Borge, find out more about the control for the laser if you can. If it is a ttl signal it should be a piece of cake I would think. I'm only guessing here but I would think you could set it up either as a plasma since they have many of the same characteristics or maybe a couple of custom macros or customise the M3 for spindle/laser on and M5 for spindle/laser off. If the later would be the case useing a standard post processor would work fine I would think. Hopefully someone who has already done this will give a little more information but I have no doubts it could be done.

Brett
;D If you could see the things I have in my head, you would be laughing too. ;D

My guard dog is not what you need to worry about!
Re: How do i setup Mach3 to control a laser with TTL input?
« Reply #2 on: April 08, 2009, 08:50:12 AM »
Hi,  i got a cheap chinese machine (300x250mm x 40W), the machine came with moshidraw software , very unfriendly, slow.
I disassemble the entire machine, fixed correctly all guides and rollers, swapped the original  driver card and put  two router controler cards to X , Y and take the Z signal in paralel port pin to fire laser.  Now I can draw on artcam or Corel, cut Vectors and engraving at hight speed. I use Mach3 as controll software.
watch that:

0,5mm card boad cutting:    http://www.youtube.com/watch?v=L-YyxtKGTEU
5mm plywood cutting:     http://www.youtube.com/watch?v=DE5_8XmGsv4   
Re: How do i setup Mach3 to control a laser with TTL input?
« Reply #3 on: June 11, 2009, 09:39:34 AM »
Laser737. care to share some more details.

What controller board(s) did you use for the X/Y axis, and how did you wire them?

How is the laser interface controlled, directly from a breakout board?

What settings did you need for Mach3 to allow PWM of the laser?

Can it raster engrave too - any examples?

Thanks,
Zax.
Re: How do i setup Mach3 to control a laser with TTL input?
« Reply #4 on: June 11, 2009, 10:34:28 AM »
Hi Zax,
In short, I did mach "think"  that  is controlling a 3 axis  router, u can use any cnc router two axis card, u ll find alot in ebay, to fire laser i use a TIP 122 in paralel port  DIR pin .
So when mach " down Z" from zero the laser fire, when up stop,
I use ArtCam to make cutting or engraving setup than open it in mach and run, no gcode edition needed,  in artcam i create tools and  input a hight speed in Z azis setup, i imput 999999999 mm/sec , like tool diameter= 0,15mm - forward speed = 5mm/s , ( acreate 5 tools whith diference forward speed : 5 - 10 - 20 - 30 - 40 , i use 40 to engraving ) but u must imput in Z axis 9999999999 mm/s in all tools, it make laser on/off instantly.
It can cutting or engraving. Here    http://www.youtube.com/watch?v=DE5_8XmGsv4    u can see engranvig acrylic after cut plywood.
the machine runs fast like a rocket     http://www.youtube.com/watch?v=L-YyxtKGTEU  - engraving mdf http://www.youtube.com/watch?v=KQ6nRlcucUA

Offline Chaoticone

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Re: How do i setup Mach3 to control a laser with TTL input?
« Reply #5 on: June 12, 2009, 06:32:17 AM »
Laser737, thanks for the video links, very neat. Good job.  :)

Brett
;D If you could see the things I have in my head, you would be laughing too. ;D

My guard dog is not what you need to worry about!
Re: How do i setup Mach3 to control a laser with TTL input?
« Reply #6 on: June 12, 2009, 09:58:49 AM »
Laser737, very interesting... and simple solution.

I would prefer to control laser power density with PWM, as not all materials like full on. I also need the ability to raster as most of my work is engraving.

At the moment I use ArtCam to setup designs and then Newlydraw to output them, but would sure like to get away from that software.

Zax.
Re: How do i setup Mach3 to control a laser with TTL input?
« Reply #7 on: June 12, 2009, 10:51:49 AM »
ah ok,
but need u controll laser power in real time? to make 3D engraving? i c...  i use a simple potenciometer to control laser power, it work fine but i can only adjust power before  run machine. Now i´m working to control power by software . 
Re: How do i setup Mach3 to control a laser with TTL input?
« Reply #8 on: June 12, 2009, 01:18:41 PM »
I think the answer is to hook a Digispeed up as my laser accepts 0-5v input for power.

I would still require fast switching (PWM). For example, when engraving glass you get much better results if you have a lower DPI. The laser causes micro fractures so having them close together causes them to join and blur the result. Individual micro dots creates a much cleaner result.

Still not sure if Mach is the way to go since it appears limited regarding raster.

Zax.

Offline Tweakie.CNC

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Re: How do i setup Mach3 to control a laser with TTL input?
« Reply #9 on: June 13, 2009, 10:13:06 AM »
Hi Borge,
The laser TTL spec is usually <0.5volts for off and >2.0 for on. Providing it does not draw any appreciable current this input can be connected to the Z axis direction pin  on the BOB so that it turns the laser on for -Z moves and off for +Z moves. I disable the Z axis so that the laser focus is not disturbed and use the Z axis DRO scale factor to control the 'laser bite time' (which varies from material to material). If the laser operation is reversed then change the direction active low under ports and pins.
Although I have used this method quite successfully I now favour a simple shutter system to switch the laser beam on and off, again using the Z axis direction signal as I believe that longer laser life will be achieved by using a soft start when it is turned on from cold.

Tweakie.

There is some further information here :-

http://www.cooperman.talktalk.net/index_files/Page4549.htm
« Last Edit: June 13, 2009, 01:02:57 PM by Tweakie.CNC »
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