Messages

771

General Mach Discussion / Re: deviations of 0.3 mm, in small parts: MACH3

« on: January 07, 2010, 04:38:51 PM »

"Under all circumstances, most tooth-belts have remarkable backlash" - That's just not true.  There are MANY toothed belt systems that have essentially zero backlash, otherwise you would not see them used in CNC drives.  XL belts are VERY common in CNC equipment, as are the newer, and even better, GT2 belts.

Regards,
Ray L.

772

General Mach Discussion / Re: Repeat paths & integration

« on: January 06, 2010, 04:42:46 PM »

If the program you're running is really that simple, you could do the whole thing in a macro:

TRIGGER_IN = OEMTRIG1              ' Mach3 signal to trigger code execution
ACKNOWLEDGE_OUT = OUTPUT1  ' Mach3 signal to send acknowledge at end of execution

While 1

    ' Wait for input, when true...
    WaitForTrigger()
    Code "G01 X0.6 F2.0"
    Code "G01 X1.2 F10.0"

    ' Pulse output
    SendAcknowledge()

    ' Wait for input, when true...
    WaitForTrigger()
    G01 X0.6 F2.0
    G01 X0.0 F10.0

    ' Pulse output
    SendAcknowledge()

    ' Wait for input, when true...
    WaitForTrigger()
    G01 X0.6 F2.0
    G01 X1.2 F10.0
    ' Pulse output
    SendAcknowledge()

Wend

Sub WaitForTrigger()
    While IsActive(TRIGGER_IN) = 0
        Sleep 100
    Wend
End Sub


Sub SendAcknowledge()
    ActivateSignal(ACKNOWLEDGE_OUT)
    Sleep 100
    DeactivateSignal(ACKNOWLEDGE_OUT)
End Sub


You can put the above code into a file named M999.m1s ("999" can be any number over 100) in the Mach3\macros\<YourProfileName> directory.  Then, typing M999 on the MDI line, or in a G-code program, will run the macro.  Since it's an endless loop, you'll have to use E-Stop or ESC to terminate it.  Alternatively, you can put the WaitForTrigger subroutine into M998.m1s, and the SendAcknowledge subroutine into M999.m1s, then use M998 in your G-code when you want to wait for the external trigger to be asserted, and M999 when you want the acknowledge to be sent.

Regards,
Ray L.

773

General Mach Discussion / Re: VistaCNC iMach/iMachPro pendant Driver

« on: January 05, 2010, 11:21:43 PM »

I'm probably going to purchase one of these pendants soon.

What do you recommend.. the USB, or parallel port version?

Your plugin here... work good with 4 axis set-up?

There is no USB version....  Works fine with 4-axes.

774

General Mach Discussion / Re: CNC4PC C11G Analog Output Spindle Control

« on: January 04, 2010, 11:22:32 PM »

Personally, I'd take a PWM spindle control interface over a Step/Dir charge pump any day.  Peter Homanns DC03 works flawlessly, and is VERY accurate and linear.  I can typically set VFD frequency to with 0.5Hz or better.

Regards,
Ray L.

775

General Mach Discussion / Re: Why not G54 instead of G52 for multiple parts?

« on: January 04, 2010, 12:05:57 PM »

If you know the part offsets in advance, it's probably easier to hard-code them into the program using G62/G92.  If not, then it's probably easier to setup fixtures manually with G54-G59, and not have to modify the code for each run.  But, either will get the job done.

Regards,
Ray L.

776

General Mach Discussion / Re: Using The Knee For Tool Length Compensation

« on: January 03, 2010, 09:29:43 PM »

One clarification:  The M843 and M849 macros require only the (optional) LED, no DROs.  The M808 and M809 macros use the probing macros in the other thread, which require a number of non-standard DROs to set the probing parameters.

Regards,
Ray L.

777

General Mach Discussion / Re: Using The Knee For Tool Length Compensation

« on: January 03, 2010, 09:01:33 PM »

BTW - The rest of my probing macros are available here:

http://www.machsupport.com/forum/index.php/topic,13624.0.html

Regards,
Ray L.

778

General Mach Discussion / Using The Knee For Tool Length Compensation

« on: January 03, 2010, 08:44:08 PM »

Below are my new macros for using the knee for tool length compensation.  This is a capability Mach3 does not currently really support, so I had to use a slightly kludgy, but perfectly functional, approach, that will be done away with as soon as v4 is released.  This means you cannot use G43 and G49, but instead must use M843 and M849 to perform the same functions.

Four macros are provided:

M808 is used for probing the length of the "master" tool.  It is strongly recommended that a "dummy" master tool be used that is as long, or longer, than any real tool  I use a piece of 1/2" rod, with a spherical end, in a spare endmill holder.

M809 is used for probing the length of all tools but the master tool.  The probing procedure is to first run the M808 macro on the master tool, then run the M809 on each subsequent tool.  See the header of the M808 macro for more details.

M843 is used, in place of G43, to enable tool length compensation.  The P parameter is used, in place of the H parameter, to specify the tool whose offset is to be used.

M849 is used, in place of G49, to disable tool length compensation.

The macros currently use one non-standard DRO, and one non-standard LED.  The macros themselves are quite simple to modify if you wish to change this, as only the main body of each macro uses the DRO or LED, and each is only a few lines of code.  All subroutines are identical to ones in the probing macros I posted earlier today in another thread.

Regards,
Ray L.

779

General Mach Discussion / New Probing/Measuring Macros

« on: January 03, 2010, 03:56:24 PM »

Below are my latest set of probing and measuring macros.  They provide the following capabilities:

Locating any edge of an objects, the mid-point between two edges, the center of a circle or pocket, and precisely aligning a vise to the X or Y axis.  All of these can either zero the axis DROs to the probed features, or simpy position without zeroing the DROs.  In addition, most operations can be performed for measurement purposes only, simply reporting the distance measured - for example, from the current position to an edge, the distance between two edges, or diameter of a circle.

The major improvement here is use of a two-stage probing technique - First, a high-speed probe is performed, to find the edge quickly.  Then, the probe is retracted about 0.020", and a second probe performed, at slow speed, for better accuracy.  This has consistenly given me 0.0001" repeatability, using a 50 IPM fast probe pass.  Since over-shoot is likely at such speeds, I do NOT recommend use of rigid probes.

These are not quite usable "out of the box", as they get a number of parameters from non-standard DROs.  So, you will have to either add these DROs to your screenset, or modify the macros to hard-wire these parameters.  All parameters are loaded in a subroutine, and the subroutine is identical in all macros that use it, so modification of the code is quite simple by simply modifying one copy, then copying/pasting it into the other macros that require it.  A brief explanation of what's required is contained in the included .txt file.

Note that I am providing these as-is, and cannot provide more than very minimal support and hand-holding.  If you're a "newbie", or not comfortable with Mach3 VB code, this is probably not for you.

Regards,
Ray L.

780

General Mach Discussion / Re: Stupid Probing Question....

« on: January 03, 2010, 01:16:15 PM »

So, the more I learn about how the type of probe I have really works, the less I like it.  It's great for doing surface and outline probing, and measurement - any operation where you don't really care if the tip is perfectly concentric to the spindle centerline - but just seems like a huge hassle for doing machine setup, which is what I'm most interested in.  I'm definitely going to make myself a contact probe, with a Mach3-proof spring-loaded tip.  It will be FAR easier to calibrate, and should maintain calibration much better.  And, it will trigger on first contact, not at some later switch opening point.  I've got a nice, simple design in mind.  Hopefully I can get it built up in the next week or so.  I plan to use a ball-bearing as the spherical probe tip, and a spring pre-loaded spherical ball bearing as the primary support.

Regards,
Ray L.