Hello Guest it is May 13, 2021, 07:44:23 AM

Author Topic: Mach 3 Laser config  (Read 20692 times)

0 Members and 1 Guest are viewing this topic.

Mach 3 Laser config
« on: November 13, 2014, 08:29:46 AM »
Reposting here hoping somone can help me

Hi

I have a problem with the configuration of mach 3 and laser.

CNC Machine is a heiz 720T, this http://goo.gl/z2THoM laser kit is from J Tech Photonics using latest version of mach 3

I have managed to get it working with the db25 dual breakout board connecting pin 17 and 25 to laser board and making output to #3 and M3 Command on mach and creating a new profile in mach 3 for laser

My doubts are :

How can I stop the Z axis from moving without disabling it in ports config in mach 3 ?

After testing the laser I notice that it is burning too much especially near the edges of the drawing is there some setting to correct this ? I have tried to increase height and speed but problem remains.

Can someone please help me ?

Thank you

Offline Tweakie.CNC

*
  • *
  •  8,706 8,706
  • Super Kitty
    • View Profile
    • Tweakie.CNC
Re: Mach 3 Laser config
« Reply #1 on: November 13, 2014, 12:24:20 PM »
Hi Hydrops,

Basically, if your Gcode does not contain any Z axis moves then the Z axis should not move – simple as that really.
Perhaps use a text editor with ‘search and replace’ to delete any Z axis commands from your Gcode??

If you attach a picture, or two, of the excessive burn near the edges of the drawing this may give us a better understanding of the cause of the problem.

Tweakie.
KEEP SAFE !
Re: Mach 3 Laser config
« Reply #2 on: November 14, 2014, 12:34:28 PM »
Hi Tweakie,

thank you very much for replying

I use vectric aspire, is there any way I can do this besides deleting all z commands ?

I am considering buying pic engrave pro laser, do you know if this progam eliminates the z commands, which I thought it would but just to be sure.

I would prefer a program that I don't have to do text editing

Regarding the photos of the excesive burn, I will take some later and post here.

Just to have an idea, what stepover should I be doing for laser engraving ? In this case I created a tool in aspire with .2mm for the laser

Offline Tweakie.CNC

*
  • *
  •  8,706 8,706
  • Super Kitty
    • View Profile
    • Tweakie.CNC
Re: Mach 3 Laser config
« Reply #3 on: November 15, 2014, 01:39:09 AM »
Hi Hydrops,

1) The easiest way is to modify the Vectric post processor to include the M10/M11 commands and remove the Z axis commands. If it's any help to you, one of my modified post processors is here http://hobbymaro.puhasoft.hu/Tweakie/Laser.zip

2) John's PicLaser software allows the choice of axis letter for the laser trigger. With TTL work you just use the axis direction signal and with Greyscale work the actual axis position (either detected electronically with step/direction controlled electronic potentiometer or mechanically with rotary encoder - but there are other options).

3) A stepover of 0.15 to 0.2 mm is usually about right.

Tweakie.
« Last Edit: November 15, 2014, 05:49:04 AM by Tweakie.CNC »
KEEP SAFE !
Re: Mach 3 Laser config
« Reply #4 on: November 15, 2014, 09:47:01 AM »
Your step-over (Pixel Resolution in PicEngrave) for raster engraving images should be based on your focal point burn line. If this is set too small, overlapping of the burn lines will occur and detail will be lost and if it's set to high, un-burn lines will appear in your engraving. The smaller the focal point is, the finer image reproduction detail that can be achieved and gives a more intense burning power so you can engrave at a higher feedrate.

As Tweakie stated, you can set to a different axis letter other then Z and use another axis direction pin to TTL engrave using a Dithered image. PEP will generate Dithered images and allows A,B, & C axis letters also. There is another option in PEP that will allow you to use a Variable Feedrate (X,Y & F) to get shading using a TTL or CW Laser Diode drivers, but this requires a very good heat sink on your Laser Diode because it will run at full power for long periods of time. However, it does give excellent 8bit shading results.

Jeff

www.picengrave.com
Extensivly Re-worked/Re-designed/Modified Servo K2CNC KG-3925 and the Mini Laser Engraver
Re: Mach 3 Laser config
« Reply #5 on: November 20, 2014, 12:40:24 PM »
Thank you both very much for the replies

I will post a photo of the burned sample soon as I'm not near the machine right now

Tweakie, I downloaded the file where should I put this file ? Is it a script to open in mach 3 ?

As you guys said I would prefer to assign other axis but Z to control the laser and I would prefer a method where I don't have to edit every gcode file I load into mach 3.

Sorry for dumb question but what is TTL  ?

Jeff, do you have a link where I can read more about the variable feedrate ? Regarding the heatsink I have the mist hose installed on the machine which can also spray air only, can this be used to cool the diode ?

And by what I understand in PEP it is easy to assign other axis than Z, is this correct ?

Thank you for your patience, I'm having quite a hard time understanding and getting this stright
Re: Mach 3 Laser config
« Reply #6 on: November 20, 2014, 01:24:07 PM »
TTL is a type of modulation input which is 0v is laser off and 5v is laser on so you can pulse the laser. J-tech's TTL laser driver will also except a 5v max PWM signal to turn the laser on and off (pulse) at a very fast frequency.

The info is on our web site about the Variable Feed Rate in PDF links in the PEP page. You can also download the Demo from there. http://www.picengrave.com/PicEngraver%20Pro%204%20+%20Laser.htm

There is a fan avaliable for the LD heat sink on J-Tech's web site. Not only will it cool the heat sink, it will also blow the smoke away when engraving. It will also help to keep contaminates from collecting on the lens.  http://jtechphotonics.com/?product_cat=accessories

If you do use the VFR code, do not set the driver at no more then 1.7a. That is the maximum recommended amp input for the 9mm Nichia 445nm LD.

Jeff

www.picengrave.com
Extensivly Re-worked/Re-designed/Modified Servo K2CNC KG-3925 and the Mini Laser Engraver
Re: Mach 3 Laser config
« Reply #7 on: November 20, 2014, 01:39:46 PM »
I will read the pdf now.

regarding the fan I already brught with the kit, in fact it's got 2, one for the laser and one for the laser circuit board.

Can the M10/M11 commands that Tweakie refered to be implemented with PEP and do you have a tutorial explaining how to do it ?

Thank you very much
Re: Mach 3 Laser config
« Reply #8 on: November 20, 2014, 01:48:45 PM »
Not at this time will PEP generate the M10/M11 commands.

Jeff

www.picengrave.com
Extensivly Re-worked/Re-designed/Modified Servo K2CNC KG-3925 and the Mini Laser Engraver
Re: Mach 3 Laser config
« Reply #9 on: November 20, 2014, 01:52:34 PM »
So, if I understand right PEP will only work with Z axis for laser control, is that it?