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Messages - charliev

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1
General Mach Discussion / MAXNC and linear motion (G00 and G01)
« on: March 08, 2013, 11:28:48 PM »
Hello,

I have my MAXNC CL10 working with MACH3 and I did some cutting today, yay!

I have a mystery that I hope a MAXNC user can help me with... it appears the the MAXNC treats the G00 and G01 code the same (unless I am totally missing something since I am a newbie...)

Here's my setup...
1. With a piece of plexiglass in the vice, I brought the endmilll down within 0.0375 of the TOP of the piece (used a 0.0375 feeler gauge)
2. Zero'd X/Y/Z on MACH3
3. Turned on the spindle and set spindle speed and issued this command: G01 Z-0.0375 F4.0
4. Endmill now is basically on the TOP surface of the piece
5. Next, issued this command: G01 Z-0.50 F2.0

Here's my issue... I expected Z to be -0.50 away (relative) from the last command, instead it went to an absolute Z distance of -0.50 (what is was expecting was an absolute distance of -0.5375)

a) Am I using the wrong G code to accomplish a relative position? Have I got the wrong idea what the G01 code does? If so, what is the linear motion code that moves RELATIVE to the current position?
OR,
b) Does the MAXNC controller not recognize the G01 (or relative position code) and interprets it like a G00?

-charlie

2
General Mach Discussion / Re: MAXNC CL10 "qaudrature" and MACH3
« on: March 08, 2013, 11:12:04 PM »
Wow, this was excellent info, THANK YOU for taking the time to post this!

I read through the info (except the EDN link didn't work, I think I need to create a login...)

So, it appears that the phase (in reference to A/B) is the direction... is it true then that the *step* is incremented on a rising/falling edge of the wave? When looking at the video  - the o-scope seems to have a constant wave when the motor was NOT running? If steps are either the raising or falling edge... then I would think that A/B would be a constant hi or low while there was no motion (?)

So, still a bit unclear how I would decode *step* info.

-charlie

3
General Mach Discussion / MAXNC CL10 "qaudrature" and MACH3
« on: March 07, 2013, 03:58:41 PM »
Hello,

Finally got my MACNC CL10 running under MACH3 using the MAXNC CL mode... yay!

Can anyone explain the theory behind "quadrature" vs. "step and direction"? I find MAX to be useless when it comes to technical documentation (or any documentation for that matter).

The scope of what I'm looking for is this... I want to count STEPS coming out of MACH3 with a separate circuit (like a PIC), however, since both MACH3 and the MAXNC CL are utilizing "quadrature" I'm not familiar with that... would anyone be interested in explaining that, else pointing me to a link that explains it?

I understand the "quadrature" count, but don't have a reference of how it relates to STEP and DIRECTION.

All help is greatly appreciated!
Thank you!
-charlie

4
General Mach Discussion / Re: Laser modulation signal?
« on: March 07, 2013, 03:37:31 PM »
I don't have much \$ invested; enjoying the theory, design and problem solving at this point. I have a couple of lenses that will allow me to focus the laser - so, we'll see... if not, then I'll do some engraving with it!

We'll see....

-charlie

5
General Mach Discussion / Re: IPM of table does not match (F)eedrate
« on: March 07, 2013, 03:27:49 PM »
Ahhh, of course, makes sense John!
Thank you!
-c

6
General Mach Discussion / Re: Laser modulation signal?
« on: March 07, 2013, 03:20:07 PM »
Hi John,

Kapton and Mylar are films of choice when making inexpensive SMT stencils that are cut via Laser, Kapton being much more expensive and durable. I have an IR laser diode and am told the film must be a dark as possible... I want to experiment with colored acrylic sheet at the same thickness once I am successful with Kapton and Mylar...

To your point about burning... this is why the laser needs to be pulsed. The link that Fred27 posted in this thread explains the issue of cutting very well and shows pics of various pulse rates, etc. Such a control would "dial-in" the correct setting for making the best cut, and would scale this setting with the travel/speed of the table - all for uniformity.

Everyone's input has been quite good, and I appreciate everyone's response to my questions!

-charlie

7
General Mach Discussion / IPM of table does not match (F)eedrate
« on: March 07, 2013, 02:51:11 PM »
Hello,

My background is software development... I've *finally* gotten my MAXNC CL10 working with MACH3 (which was no small feat). I'm in the process of confirming that the MAXNC table is 1:1 with MACH3...

The table X/Y/Z seems to be dead-on correct with the SRO of MACH3... however, when I issue the following command:
G01 X4.0 F4.0
In order to move the table 4 inches to the right at 4ipm feed rate... it takes 1:23 to do so. In my development world this is unacceptable... however, I have no machinist background.... shouldn't the actual feed rate of F4.0 be  *close* to 4 inches per minute on the table?

Again, keep in mind this is a MAXNC... where probably all bets are off...

Just looking for some feed back... AND, if there is some setting that I can fool with in MACH3 please let me know... Steps are set to 8000 (and as mentioned) seem to be correct distance-wise.

-charlie

8
General Mach Discussion / Re: Laser modulation signal?
« on: March 07, 2013, 11:49:44 AM »
Thanks Fred27, I'll give it a look.
-charlie

9
General Mach Discussion / Re: Laser modulation signal?
« on: March 07, 2013, 10:33:39 AM »
Hi John,

This may only be my ignorance as I have never worked with a Laser cutting application before. The SMT Stencil needs to be accurate with a very good/sharp edge. Since the unit I am attempting to utilize is only 1W (and I consider this very low power for a cutting application) I wanted to utilize "full power" in the cut.

In order to dial-in the fine edge I require, I felt that I would need to pulse the laser so the material does not burn. I've run this buy the vendor that sourced the laser diode and optics and he concurred.

I need to go through (at least) 0.005" material, and I don't believe anything but full power will accomplish this...

I noticed that my table (and I assume any table) ramps up/down with speed... furthermore, I want to be able to set speed in my G Code... I'd like to build a "follower" circuit that will vary the laser pulses, such that the pulses are uniform across speed changes... this would require some varying signal to come from MACH3 (easiest) or the Mill itself to trigger the Laser.

As I admitted, I have no Laser experience, but theoretically, if I need a desired cut *depth* without burning, I'd need to pulse the 1W Laser rather than varying the output.... but, I'm open to new, more experienced thinking.

Thoughts?
-charlie

10
General Mach Discussion / Re: Laser modulation signal?
« on: March 07, 2013, 09:24:07 AM »
Thank you for the replies!

Dan: Can you provide more info on how this is setup in MACH3?

Tweakie: The Stencil starts-out as a GERBER file that gets converted to DXF. These are vector files, I believe I'd loose too much resolution going to a raster image to suite the apps (unless they support GERBER or DXF).

Since the laser is so low power, I'd like to toggle it full power at some interval that varies with speed - I am not against creating my own circuit from a PIC... maybe OR'ing the STEP signals on X and Y, running this through a lowpass filter to create a DC voltage (table speed indicator...) then use that to vary the frequency of a PWM signal that is set to make the best cut... this signal would trigger the modulator to pulse the laser at a desired frequency and vary the pulse accordingly to the speed of the table.

Not sure if I'm on the right track... (?)

-charlie

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