Mach3turn problem notice

[johnas]

Incidently, the spindle will sync quite well for short thread lengths, but from what I have heard is that after a few inches of length for threads the timing gets muddled or something. I believe it's something like four inches or so. I've threaded several items without problems... one was the ballscrew end for bearing block mounting of my router after cutting it to length. I hope you can live with your limited use of Mach3turn until the super low cost of Mach4 comes out.

Nice work, BTW.

My understanding is that Mach3 uses one sync pulse on the spindle, and an averaging algorithm to determine z movement speed.

This is fine if your spindle speed is absolutely rock solid, but if it wavers slightly (say, when cutting metal) ;-) then the rotational accuracy/z position suffers.

For my LinuxCNC build, I'm following the usual way for LinuxCNC - an index pulse, and a number of sub-pulses (32? 64??) to actually give pretty good rotational accuracy.

Really, if you think about it, the averaging speed scheme can only result in inaccuracy, unless you have a rock-solid spindle drive. I don't know about you, but none of my lathes (4) are rock-solid; my 11x24 one is pretty good, but the clutch needs re-adjustment.

I'm not sure how many sub-pulses to give my lathe spindle - something to experiment with when I get it running.

I'm very happy with LinuxCNC and my mill hardware, I expect the same level of gratification with my lathe build - but time will tell...

 

[jumps4]

this is my pride and joy build
http://www.hobby-machinist.com/showthread.php/8187-rung-fu-clone-RF-45-ZX45-cnc-conversion
the lathe was fun but i never put into it what i have the zx45
i have been so tempted to look into linuxcnc but i'm funny about not trying to get into too many different things all at the same time, it makes mush out of my tiny brain
steve

 

[jumps4]

Here is a possible alternative or addition to Mach3turn that you might find useful:
Mach "lazyturn":
http://www.machsupport.com/forum/index.php/board,73.0.html

The manual:
http://www.machsupport.com/forum/index.php/topic,10091.new.html#new

Art did this after selling the Mach3. Rich wrote the manual.

I have lazyturn and have to go back and take a better look now, i thought i was doing the right thing by staying with the basic version to keep things simple untill i had the bugs worked out and never thought my problems were software, i always though it had to be something i was or have done wrong somewhere.
i will give it a closer look
thank you
steve

 

[Bloy]

5 minutes later the lathe started feeding at full z axis speed and burried the cutter into the part so deep it stopped the spindle motor and was smoking the belt, and the stepper motors were just screaming. steve

This doesn't sound at all like a software problem. I would begin to suspect EMI / RFI, breakout board or something related in the cabling. Power wiring parallel to signal feeds? I'm not saying it isn't Mach3, but your example doesn't sound like it is either.
Any errant programs running in the background? Those kinds of problems are tough to sort out.

Heh! Right now I've been rebooting this computer several times and fiddling with the memory sticks. It started to get slow so I checked the available mem and although I got two gigs, only one was recognized.

 

[jumps4]

I have 2 cnc lathes and 2 cnc mills each with their own pc that does nothing but run that machine, thats all the pc does
it only happens if i try to change feed rate when running if i dont touch anything the program completes perfectly
and the problem also happens if you try to pause and restart then the program gets lost and may not start in the correct position even if i didnt make a move while paused. as long as i start the program and not stop anything everything works.
there is nothing else on the pc i know of that would run it is gutted out just the basics and no network or internet enabled
i can do a " run from here" move just not a pause and restart some times, i think its only when contouring, straight line moves work fine and can be paused and restarted i have run versions from 22 thru 67 trying to get rid of different issues and maybe i find a fix for one and cause something else i havent seen before.
can you change your feed rate in turn while contouring and if so what version are you using?
my system is clean signals nice wave forms and i have no ground loop issues i can find
i'm pretty sure it's software or settings related and may have to do with sync mode being enabled
if i have to set everything in setup for threading different than normal contour turning, making complete parts with lots of operations is not going to work very well. i make one of a kind parts if i was perfecting code for a run of parts it would be easier to get smooth operations figured out and adjust things to work the best for the run. but if i have to change setups for different operations it will be no fun.
steve

 

[jumps4]

I'm pretty good at the wiring and emi/ rfi solutions/prevention
look at all the shielding lol
steve

 

[johnas]

this is my pride and joy build
http://www.hobby-machinist.com/showthread.php/8187-rung-fu-clone-RF-45-ZX45-cnc-conversion
the lathe was fun but i never put into it what i have the zx45
i have been so tempted to look into linuxcnc but i'm funny about not trying to get into too many different things all at the same time, it makes mush out of my tiny brain
steve

I understand the "change the software issue" - I have not had a Microsoft-based OS on my desk since 1996, so I'd be worried about going to Mach3!

Anyway, for me, it's LinuxCNC, as it works very well, and I have figured it out. I can't bash Mach3, nor can I compare directly; I just understand from the LinuxCNC mailing list, and other boards, that people migrate to LinuxCNC for lathe control. Possibly, there's migration the other way, too, but I don't read those forums or email lists! ;-)

Good luck, and I hope you solve the issue, one way or the other. I really enjoy your postings, please keep going.

 

[Bloy]

can you change your feed rate in turn while contouring and if so what version are you using?
my system is clean signals nice wave forms and i have no ground loop issues i can find
i'm pretty sure it's software or settings related and may have to do with sync mode being enabled
steve

As I say, I'm dusting off my machines, so haven't used them lately.
If I recall, I don't think feedrate changes in mach3turn in sync mode during operations should be done. That may be one of the major "glitches" in Turn.

I never trusted my machines to change the feedrate during operations, although many do. I just did air and scrap tests until I found a comfortable rate to run the code from start to finish....in turn. If I were trying to achieve some level of production, I might be as miffed as you are. Just consider the cost for what it DOES do.


If I were you, I would flood all your pictures and information into the Mach forum and see if you can get answers. Maybe at least you will learn the limitations of Mach3Turn from some of the regulars there, and maybe some workarounds.
You'll get better responses by informing concisely what you experience. But be nice!

Remember, show them your setups .


Your electrical system LOOKS good, in fact down right nice! But it does not necessarily exclude sufficient voltage pullups and sinking. Many problems are the differences of computers with 3.5Vdc rather than 5vdc, although I would think you have that covered.

I myself have been thinking of diving into LinuxCNC for lathework and if I "get it", may expand to mill. But i like Mach3 for mill, routing.

You might want to peruse this guy's work. He has developed a great turning center using the mill. He has a trunnion fourth axis and other devices.
here is his thread...it is long but skimming through it will reveal many pictures to go along with his explanations.

http://www.machsupport.com/forum/index.php/topic,11422.0.html

Here is his video page
http://www.youtube.com/watch?v=2KNit__LJE4

 

[jumps4]

my mill runs on a uc100 usb controller at 200ipm without missing steps ( not that i will run it at that! the 300lb head moving down at 200ipm is scary ) i have max set at 100ipm
and now that i know there is a fix on the way from brian for turn i'm going to do my mods to the lathe anyway ( i bought the parts ) because it will be fixed with mach4. until then i do this as a hobby so there is no real reason to panic.
steve