question in using mach3 in a laser cnc

[waleed alhadidi]

Hi
i am new in using mach3 in a laser cnc , and my question is : how can mach3 control the time of running the laser head ? if i want to run the laser for a specific time period then how can i control this period ?

thank you
waleed

[boern69]

Hello , I have the same question
I already read,
that someone controls his laser with the pwm modulation
of the axis stepper in mach 2d mod.

I have a synrad 48-1
tickle freq 5khz
pulse length 1mikrosec +- 0,2 mikrosec
raise fall time <= 100ns 0,5v to 3,5V dc nominal is 5vDC

Can anybody explain how to control wtih mach3 or linkmotion software

I prefer mach3 because I already have it!

Thanks and best regards bjoern

[Mongkol]

Hi All,
Mach ---->can do only vector,can not do raster method.
Link motion----> can do both vector and raster method.
Laser, Mach can not engrave on material. It can only cut.
In another way, Link motion can do both engrave and cut on material.

Cheers,
Mongkol

[waleed alhadidi]

that's ok mongkol , 2D cutting is all what we want with laser , but the question is still : how can we use mach3 for 2d cutting with laser ?

[boern69]

Can any one imagine to take the pwm control of the z-axis for using
as the power control of the laser.... and explain it here.
Perhaps a pic( microcontroler) will be useful but without it will be less
complicated.

thanks regards

[waleed alhadidi]

I have no good knowedge at laser systems but i expect that the laser pwm controller comes with the laser head and not connected to the program .

[student1616]

at first i belive the same.
but after looking at this videos,i think its quite possible to use mach3 to do engraving.
"http://www.youtube.com/watch?v=gnZ26ZAfo4c"]YouTube - CNC laser ploter burns evil monkey
i have no idea how to do that.iam trying to contact the author.once i get some info,i'll sure do share.

[waleed alhadidi]

Thanks student1616,
We are waiting for the new information from the author.

[PoppaBear10]

Hey Fella's mabey I can help. (BTW Mach can do Laser Engraving)

I have NOT ever run a Laser, but I do alot with Mach controls.

So if my assumptions are wrong, please correct me and define the issue step by step, and I can try and help you with a solution.

PWM: In mach3, under Config->Ports and Pins, Tab to the "Spindle", on that dialog page you will see a setting under Spindle that allows PWM control.
So, you can use the "Spndle" to control your lazers output.

For instance lets say "S0" would equal Laser OFF, and "S100" would = Laser ON at full power.

Set under "Config->Spindle Pulleys set Pulley #1, range 0-100, ratio 1.

What this would do is as your "Spindle speed" would range from what ever you programmed fron 0-100&#37; power.

You can use the M3 command to Enable the Laser unit as a whole if you want, and M5 to Turn off the Lazer as well.

If you dont want to use the M3 and M5 commands, and just use the PWM for laser outputs for 0-100%, then use One of Mach3's Enable outputs as a safty that will Dissable the Laser for an estop, and enable it when mach is in non-Estop mode.

LASER ENGRAVING: There is a Plug in for this on the Download Plugins of the Mach support site about 1/3rd of the way down the page.
http://www.machsupport.com/plugins.php

scott

[lasersafe1]

Hello all,
I finally got fed up with the MoshiDraw software that came with my Chinese 40W laser engraver. I purchased Mach 3 to run my mill, so it was a quick change to get it on my laser. I replaced the stepper drives and set up output 1 (Spindle) to trigger the laser on and off. First run was with Arts "roadrunner" file. This file turns the spindle on at start and off at the end, so the laser is running at all points between at the power setting I have manually dialed in at the laser. The spindle does not turn off during the rapids. I could go in and edit the Gcode to turn it on and off during rapids, but it would be so much easier if I could set up a trigger within Mach 3 that turns the laser on when Z= -.1 and off when Z has moved up for a rapid. Any advice out there? I really need to sit down and learn more about Mach 3. Certainly the same operations that occur for Plasma cutting could be used to trigger the laser on and off for my present paper cutting operations.
"http://www.youtube.com/watch?v=0xJH2_K8NbU"]YouTube - Laser engraver running MACH3

[Torchhead]

When the outputs (and which ones) turn on is in the POST of the CAM program. For example the POST for SheetCAM to MACH for plasma triggers OUTPUT 1 on after the XY postion moves and after a Z move to a pierce height. That would come close to what you want by doing rapids at Rapid Height, move to the start point, lower the head to a "pierce height" (which would be your cut height) fire the Laser and start moving. It turns the output off at the end of the cut and raises to rapid height and does the process all over. You need to select a CAM program that will let you control your toolpath and cut process and output proper g-code for MACH.

TOM Caudle
www.CandCNC.com
Totally Modular CNC Electronics

[lasersafe1]

I think I understand what you're saying, but let me give you the following example. Image 1 is loaded into a program called BMP2CNC. The internals of this program assume I am using a mill. It outputs the rastered cut program shown in image 2. It will POST Gcode to Mach3.

Clearly in this configuration I would want to setup my laser for PWM based on the depth of Z. A deep Z would be full power (or some max setting) and a shallow Z would be low power. The safe Z would be laser off.

This method of control would take the brand of CAM program out of the mix and Mach 3 would control power based on cut depth. For paper cutting, this would be On-off control, but when I want to go back to rastering I would want power control.

I'm sure someone out there has done this, or someone sells a device to do it. Heck, I already know my backup plan; I will actually connect a small NEMA 17 stepper motor to a 10 turn pot that sets power for my laser. Viola, Z-axis analog power control! The home reset switch for the Z axis would be created by an electronic comparator near the lowest pot setting.

This is just a fun hobby for me at the moment, but I want to explore all the things I can get this one tool to do for me. I got the laser for $950 from ebay.