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Author Topic: machine pauses after spindle/laser is triggerd  (Read 11298 times)

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Re: machine pauses after spindle/laser is triggerd
« Reply #20 on: September 16, 2009, 02:40:07 PM »
Hi guys, I am watching this thread. I am also in the process of putting together a laser system. I have a 70 watt fiber launched laser I am controlling with a Xantrex 12-100 power supply. I plan on using a DC-03 DigiSpeed GX V3 to convert the PWM signal to a 0-5 volt analog signal to send to the Xantrex power supply to modulate the laser power. I know a little more about lasers than I do g-code and was hoping I would be able to find a cheap way to generate the code necessary for laser cutting and engraving. I am starting to think I may be in over my head.
"Gravity, its not just a good idea its the law"
Re: machine pauses after spindle/laser is triggerd
« Reply #21 on: September 16, 2009, 09:42:00 PM »
Astro,

The gcode is pretty easy. If the shape you want to cut out is in dxf or can be translated to it, you can open it in lazycam and post it out to G-Code. You will probably have to edit it to make it work for your laser. This can be done with 3 or 4 find and replace operations in a text editor.

Lazycam, as you may already know, comes with Mach3.

Good luck,

Roger

Offline matd

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Re: machine pauses after spindle/laser is triggerd
« Reply #22 on: October 12, 2009, 11:44:11 AM »
Hi guys,

It's been a while but...

I have tried the technique described above by Chip with very good success. What I did was to to generate a pwm signal from the spindle output and use the relay on my BOB (PMDX 122) to open and close the circuit between pin 16 (the pin outputting my pwm) and the laser. The relay is opened and closed with the direction signal from my Z-Axis (Since my machine has none). There is little or no delay like there was with the M3 / M5 commands.

In my gcode, the power level of the laser is changed with an S command from S 0 to S 100  for 0-100% power. So at the start of my program I toggle the direction to down to make sure the relay is open (G0 Z-.001), set the power with S command then turn on the spindle with M3 and leave the spindle on thru out the program. To toggle the laser on and off, I issue G0 Z0.001 for laser on and G0 Z-0.001 for laser off.  At the end  of my program, I issue M5 to turn off pulse generation.

I can post more info about my setup when I get home (I'm on lunch at work now) if anyone is interested. Just let me know.

The next step is to figure out how to vary the power as a function of the speed of the x and y axis while using the relay to open close the signal to the laser unit. I would like to use one of the rotary axis to generate the pulses instead of the spindle but haven't yet figured out the setup to do this. Any suggestions are welcome.

Thanks for all the help guys.

Roger

Hi,

I'm having the same problem here.
How do you convert the Dir + or Dir - from the Z axis to a 0 or 5V signal ? What schematic/electronics do you use?
I was thinking about making a simple electronic tim delay on the signal, would't this also work?
Re: machine pauses after spindle/laser is triggerd
« Reply #23 on: October 12, 2009, 12:08:57 PM »
This is what I plan on using http://homanndesigns.com/store/index.php?main_page=product_info&cPath=1&products_id=21 it will take the PWM signal from Mark3 and convert it to a 0-5 volt analog signal.
"Gravity, its not just a good idea its the law"

Offline Tweakie.CNC

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Re: machine pauses after spindle/laser is triggerd
« Reply #24 on: October 12, 2009, 12:20:02 PM »
Thanks for the link - that looks like a nice piece of kit for the spindle control.

Tweakie.
Success consists of going from failure to failure without loss of enthusiasm.  Winston Churchill.
Re: machine pauses after spindle/laser is triggerd
« Reply #25 on: October 13, 2009, 08:30:11 AM »
On my machine, I am using the pwm signal from my PMDX-122 BOB directly as the 0-5V control voltage. No hardware other than my bob is required. If you put an analog volt meter on the "spindle" signal wire you will see the voltage appear to vary from 0 - 5V as the spindle speed is changed in mach 3.

In my case, the laser tube came out of a working unit (the table was just too small). Before dissassemblinig the unit, I put a scope on it. The control signal turned out to be a 5V PWM signal (The tube is a Synrad RF excited Co2 25Watt)

Let me know if you need to know how to the get pwm signal.

Regards,

Roger


Re: machine pauses after spindle/laser is triggerd
« Reply #26 on: October 13, 2009, 08:57:35 AM »
On my machine, I am using the pwm signal from my PMDX-122 BOB directly as the 0-5V control voltage. No hardware other than my bob is required. If you put an analog volt meter on the "spindle" signal wire you will see the voltage appear to vary from 0 - 5V as the spindle speed is changed in mach 3.

In my case, the laser tube came out of a working unit (the table was just too small). Before dissassemblinig the unit, I put a scope on it. The control signal turned out to be a 5V PWM signal (The tube is a Synrad RF excited Co2 25Watt)

Let me know if you need to know how to the get pwm signal.

Regards,

Roger




Yes, I would like to hear how you get the PWM signal.
"Gravity, its not just a good idea its the law"
Re: machine pauses after spindle/laser is triggerd
« Reply #27 on: October 13, 2009, 09:33:59 AM »
Sorry Matd,

I just reread your post and see that you were already asking how to make the pwm signal. As I said in my earlier post, no hardware other than my bob is required (in my case anyway).

To make the pwm signal, in mach, setup the spindle to make the pwm and the z axis to turn it on and off (since I assume your laser machine doesn't have an actual spindle or z-axis). To do this, go to "ports and pins" on the "Spindle Setup" tab set the following in the Motor Control section: "Use spindle motor output" to on, "PWM Control" to on. "PWMBASE Freq to 4166 (I could use some help understanding this. I do know a lower freq seems to cause the power to be lower (I think)) "Minimum PWM" set to 0. In the "General Parameters" section set all delays to 0. In "Special Options" everything is off.

In the "Motor Outputs" tab, The spindle is set up as follows: Enalbed checked, step pin set to 16, the dir pin is 0 (we are not changing the direction of the spindle signal. remember we are using the Z-axis to do that.) Dir LowActive and Setp Low Active both unchecked. Step and dir ports both set to 1.

Also in the "Motor outputs" tab, set the Z-Axis as follows (all we are using is the direction signal). Enabled checked, step pin is 0, dir pin 1, dir lowactive checked, step lowactive unchecked, step and dir ports set to 1. ) I have to use pin 1 which is hardwired in my bob to control the relay on my bob.

Under Config>Spindle Pulleys, set the current pulley to number 1, min speed = 0, max speed 100, ratio 1, reversed off.

Of course, you can change the pins per your setup. In this case though, I have two wires going to the control terminals on my laser.... one from the common on my BOB, the other is hooked to the normally open side of the relay on my bob. The common side of the relay is hooked to pin 16 (the pwm signal). This way the relay can open and close the circuit which is sending the pwm to the laser.

Hope this helps,

Roger