Recent Posts

11

Mach4 General Discussion / Re: Mach4 Loses Z Motion Reference After Idle

« Last post by cncmagic on July 14, 2026, 06:57:51 PM »

possibly... but not always... in some circumstances the actual application has some affect... as in my case... I found an issue that could not be easily resolved.. I did find a way to manage but because of the issue and no help from the developers I told my client to walk away from Mach4 for any future machine. This was not the first mach3 or mach4 I had done but it was a different application and gave a very peculiar problem. Took me over a year to resolve. And that's money directly out of my pocket..

12

Mach4 General Discussion / Re: G54 work offset changes after re-homing

« Last post by cncmagic on July 14, 2026, 06:50:41 PM »

yes, for most applications that is more than sufficient. And it sounds like you did your design based on good engineering practices.. that's probably why you don't have lots of issues with your machinery not doing what its supposed to do. 

13

Mach4 General Discussion / Re: G54 work offset changes after re-homing

« Last post by joeaverage on July 14, 2026, 06:40:51 PM »

Hi,
I use 5mm pitch ballscrews direct coupled to the servos. I have used the electronic gearing feature of the servo drives to effectively have a 5000 count per rev encoder, which in
turn results in a linear resolution of 1um (0.000039"). As a matter of practice I consider the smallest usable resolution of my machine is 5um (0.0002").

I have measured the repeatability of my homing procedure and it is at worst 0.02mm or 20um (0.0008"), and mostly it 0.01mm or 10um (0.0004"). Note that this is just with
good quality snap action microswitches. That I could do better by using Index Homing is not especially relevant as the homing procedure as is good enough.

Every once in a while I will mill a piece of aluminum with a 20mm or 25mm diameter boss and then very carefully measure how 'out of round' it is. The last time I did it was, about six months ago,
 9um (0.00035") out of round. This is a highly practical test, not only measuring the absolute accuracy of your machine but also its repeatability (multiple passes are taken and thus
any irrepeatable deviation would be obvious) while under actual cutting conditions, thus including flexure of the tool, spindle and machine, albeit under lightly loaded conditions but actually loaded.

Craig

14

Mach4 General Discussion / Re: G54 work offset changes after re-homing

« Last post by cncmagic on July 14, 2026, 05:37:57 PM »

yes... you can't actually calculate your accuracy without knowing the expansion of the components, this is simply a calculated number..... however if you calculate that your best accuracy is +/- 0.010" then don't be surprised when in practice you only manage +/- 0.030" or worse. . but when I design motion systems I need to know the necessary accuracy required and ensure that my gearing and other components are well with my spec. I normally go at least 10x my required accuracy. So if I need 0.001" then my design needs to show at least the ability to repeat within 0.0001"... we are drilling a 0.007" hole in a fuel nozzle... so repeatability was a major concern. Now, I didn't expect to hold 0.0001" in actual practice... parts needed to go into a fixture, but if I can show that the motors themselves could hold +/- 5 counts, and a count was 0.00005" then I could say my tolerance was +/- 0.00025" theoretical. I also need to determine the max rpm for my ballscrew (i try not to run them higher then maybe 60% of the max) and likewise the max pulse rate (freq) that both the servo and the motion board can manage. Again, I try to stay well below the max for either. just good design practices 

15

Mach4 General Discussion / Re: G54 work offset changes after re-homing

« Last post by joeaverage on July 14, 2026, 03:02:42 PM »

Hi,
I use Delta servos, and they too have their own homing procedure but I don't use it. I still use Machs homing routine and features.

you are still relying on the mechanical switch contacts break and make...

That is correct, and yet with quality snap action microswitches those switch activation and switch deactivation points are well specified and repeatable. As I posted earlier I get
0.02mm repeatability with good snap action microswitches. It was always my intention to refine that using Index Homing, as my ESS offers that feature......but I soon realised that 0.02mm
or eight tenths of one thousandth of an inch is in fact pretty damned good and I don't really need more than that.

gives me an accuracy in excess of 0.0000001" repeatability. 

I can well believe that you can calculate that level of precision but will not get within a bulls roar of it in practice. The thermal expansion of a steel ballscrew is vastly more than that.
The thermal coefficient of expansion of steel is 12um per degree C per meter. Thus if your ballscrew is say 600mm long and the temp varies by 4C from yesterday when you homed last then
the variance when you home today is 0.6 x 4 x 12=28.8um or 1.1 thousandths of an inch if you prefer. What advantage actually materialises when thermal expansion alone may be
many more times the resolution of you homing routine?.

Once I realised just the thermal expansion alone would well and truly exceed the resolution of  Index Homing (as I originally intended to do) and  was not going to make my machine
any better in practice, then I decided against the extra complexity(of Index Homing). Indeed my mother warned me that indulging in such self deceiving practices would likely be bad for my vision!

Craig

16

General Mach Discussion / Newbie trying to get Mach3 Configured

« Last post by fluterly on July 14, 2026, 11:50:20 AM »

I was given a CNC router my dad bought to play with but never got time (he bought it secondhand).  It's a 2012 or so vintage Automation Technologies KL6090 3 axis router.  It's set up with a CM100 parallel port card and a Sanfar E300 spindle PWM.  I have installed a demo copy of Mach 3 on a Windows 7 32 bit machine.

I have been able to find some documentation on the machine but I suspect the parallel port card is a new addition vs the factory.  I have been able to get the X, Y, Z axis moving and mostly working (think I need to get the homing switches figured out eventually) but my big issue is getting the spindle working.

I'm attaching a photo of the cabinet and the break out board.  I forgot to get a copy of my config, and that's at home.  I can add it if needed.  XYZ were on 2, 4, and 6 pins as I recall.  Let me know any other info I can provide.  Any help is greatly appreciated.

Thank you.

17

Mach4 General Discussion / Re: G54 work offset changes after re-homing

« Last post by cncmagic on July 14, 2026, 05:52:35 AM »

and its not a process from my motion controller... the servo's have their own built in homing procedure. Usually even the motion cards/modules don't use the 'z' marker either. They are only as accurate as the switch make and break repeatability and their own characteristics. Could be off by thousands of an inch repeatability. 

18

Mach4 General Discussion / Re: G54 work offset changes after re-homing

« Last post by cncmagic on July 14, 2026, 05:48:10 AM »

that's not the same thing... you are still relying on the mechanical switch contacts break and make... as I said, my system does it's procedure outside of Mach4 and uses the 'z' marker on the servo encoder. With the gearin I have and the encoder count, even being off a count or two, gives me an accuracy in excess of 0.0000001" repeatability. 

19

Mach3 and G-Rex / Re: Why is the Auto Tool Zero button not working?

« Last post by thomasbest on July 13, 2026, 11:13:59 PM »

It looks like the script itself isn't the problem since it runs correctly with Run Script. The "Not Yet Implemented" message usually means the Auto Tool Zero button in your controller profile or screen set isn't actually linked to a working function. In other words, the button isn't executing your M930.m1s macro—it simply hasn't been implemented for that particular screen or controller plugin.

20

Mach4 General Discussion / Re: G54 work offset changes after re-homing

« Last post by joeaverage on July 13, 2026, 05:29:36 PM »

Hi,
Mach4 has always done that, as did Mach3 before it.

The native homing procedure is:
1) the axis to be homed advances in the programmed direction at the programmed homing speed (as set in the Mach Control plugin)
2) On home switch activation the axis decelerates to a stop. Once the motion controller signals that the machine has stopped it then reverses that axis at the back-off velocity (as programmed in the
motion control plugin)
3) When the switch deactivates the motion controller decelerates the axis to a stop.
4) When the motion control signals Mach that all axes are stopped the Mach latches the axis position as reported by the motion controller in integer step units and resets Mach Machine Coordinate
Counter to zero.

There are a few variations on that general theme. For example instead of setting the Machine Coordinate counter to zero, Mach may set it to some Offset as programmed in the Mach Control plugin, Homing Tab.

Note that Mach does NOT provide a means to back off a certain distance, and never has. Starting, at first I believe with the PoKeys 57CNC motion control you could program the motion control to back-off
the home switch a programmable distance, as set in the motion control plugin. Many people found that useful and consequently all the other motion control manufacturers copied the same thing.
Thus when you program your machine to back-off the home switch by 75mm say, the actual process is that the axis homes to the switch until it activates, then backs off until the home switch deactivates,
i.e. the standard Mach homing procedure, but then the motion control drives an extra certain distance.

Index homing is another feature that is not native to Mach. It is a feature offered by the motion control.

The homing procedure with Index Homing is that the axis homes toward the home switch until it activates, then backs off only until the home switch deactivates, as per normal and standard Mach homing procedure
but then the motion control carries on the rotation of the axis stepper or servo UNTIL its index switch is activated. Then and only then does it signal Mach that all axes are stopped and Mach can latch
the machine position. That this is a feature of the motion control note that Index Homing is programmed in the motion control plugin.....not Mach's Control plugin.

So both programmable back-off distance and Index Homing are both features of the motion control and are not in fact native to Mach at all.

Note also that in every instance the core homing procedure is that the axis advanced is at the programmed speed and direction UNTIL the home switch goes active and then backs up UNTIL the switch
again goes inactive. This places a very strict demand to the repeatability of a  home switch to activate and then reliably and precisely deactivate. Most people assume that a switch with zero dead-band is
the ideal, but in fact this is incorrect. Snap action microswitches has a very precise and repeatable dead-band, also called hysteresis, and thus despite having a difference in the moment of activation verses
deactivation they perform extremely well as home switches, better in my opinion than proximity switches which have at best, a poorly defined hysteresis.

Craig