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IndustryArena Forum > MetalWorking Machines > Benchtop Machines > Mach3, Mach 4 or Linux CNC for G0704
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  1. #121
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    Re: Mach3, Mach 4 or Linux CNC for G0704

    I dont think accuracy is so much the issue in this case, its just runs lumpy. Definitely was in cv mode. Could well be that mach 3 has some retarded code that disables CV mode selection as default, this sort of stuff really angers me, yet another reason to avoid mach 3 for general mess around. Like i say the motor tuning was the same and machine is tight enough to handle the speed as you can see the proof is in the pudding with the uccnc example. . Could it simply be the lack of decent motion control in the basic mach 3 bob that comes with the Chinese 6040. Who knows, a fairer test would have been trying 3 versions one using the uc400 mach3 plugin. frankly i dont intend on looking into it as the problem has been solved by uc400 + uccnc.

  2. #122
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    Re: Mach3, Mach 4 or Linux CNC for G0704

    ah ok. then ill bet cv is disabled.
    ill go dig up the setting tonight for you and then you could retest (air cutting will tell you instantly just be sound).

  3. #123
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    35538

    Re: Mach3, Mach 4 or Linux CNC for G0704

    In Mach3, make sure that when using CV mode, that ALL CV options are turned off, except for Stop CV on Angles. Both CV Feedrate and CV Distance should be off, and all the other settings in General Config.
    And make sure your lookahead is not set to a very low number.
    Gerry

    UCCNC 2017 Screenset
    http://www.thecncwoodworker.com/2017.html

    Mach3 2010 Screenset
    http://www.thecncwoodworker.com/2010.html

    JointCAM - CNC Dovetails & Box Joints
    http://www.g-forcecnc.com/jointcam.html

    (Note: The opinions expressed in this post are my own and are not necessarily those of CNCzone and its management)

  4. #124
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    Re: Mach3, Mach 4 or Linux CNC for G0704

    Quote Originally Posted by ger21 View Post
    In Mach3, make sure that when using CV mode, that ALL CV options are turned off, except for Stop CV on Angles. Both CV Feedrate and CV Distance should be off, and all the other settings in General Config.
    And make sure your lookahead is not set to a very low number.
    I will fire it back up and double check, for the purposes of the test i simply matched the mach 3 cv settings to the default uccnc settings. cv distance & cv feedrate setting is not used in uccnc so no value would have been entered and i cant be sure whether that was on or off.

    Look ahead was set at 300 lines, angle 89.

    But to me as feedrate was maintained and cutting time matched that of uccnc, even with the cv settings (which must be off?? why is this?) id expect result to be better than they were. Just seemed like a massive lack of smoothing which does suggest ihavenofish was correct in that is was in exact stop mode and down to the complete idiocy of mach 3 in which case it Needs a warning " these settings may not actually change anything"

  5. #125
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    Re: Mach3, Mach 4 or Linux CNC for G0704

    cv feedrate, thats the one! thanks ger.

    i never turned off cv distance though (or maybe it was already off, cant remember).

  6. #126
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    Re: Mach3, Mach 4 or Linux CNC for G0704

    Quote Originally Posted by Jon.N.CNC View Post
    I will fire it back up and double check, for the purposes of the test i simply matched the mach 3 cv settings to the default uccnc settings. cv distance & cv feedrate setting is not used in uccnc so no value would have been entered and i cant be sure whether that was on or off.

    Look ahead was set at 300 lines, angle 89.

    But to me as feedrate was maintained and cutting time matched that of uccnc, even with the cv settings (which must be off?? why is this?) id expect result to be better than they were.
    if cv feedrate is set to 1 in the xml, g64/cv is effectively off.

    sometimes mach3 can go really fast with cv off, but the thing will vibrate like mad which is the giveaway that its not working right.

  7. #127
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    Re: Mach3, Mach 4 or Linux CNC for G0704

    Was correct in terms of feed rate. Sounded okay, not as smooth as ucnc but no visible or audible vibration and cutting foam is very quiet.

  8. #128
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    Re: Mach3, Mach 4 or Linux CNC for G0704

    I would say that you definitely have some type of issue to get cuts like that with Mach3, CV mode or not.
    Gerry

    UCCNC 2017 Screenset
    http://www.thecncwoodworker.com/2017.html

    Mach3 2010 Screenset
    http://www.thecncwoodworker.com/2010.html

    JointCAM - CNC Dovetails & Box Joints
    http://www.g-forcecnc.com/jointcam.html

    (Note: The opinions expressed in this post are my own and are not necessarily those of CNCzone and its management)

  9. #129
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    Quote Originally Posted by ger21 View Post
    I would say that you definitely have some type of issue to get cuts like that with Mach3, CV mode or not.
    I'm convinced it's no or poor motion control, as with many cheap Mach 3 bobs

  10. #130
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    Re: Mach3, Mach 4 or Linux CNC for G0704

    the break out board has nothing whatsoever to do with motion control. it only relays pulses from the parallel port with little or no alteration. all motion control is handle within mach3 on the pc.

    a break out is going to either work or not work. there wont be any in between - certainly none that could cause what youre seeing there.

  11. #131
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    Re: Mach3, Mach 4 or Linux CNC for G0704

    another note, some drives are sensitive to pulse timing, and will lose widely spaced pulses from mach3. geckos are notorious for this.

    whats basically happening is the drive looses steps and appears to "flatten" direction changes, like on a circle for example. it almost appears like backlash. most programs have many reversals and end up often in the same place, and can appear not to have lost position despite be waaaay out.

    if you check "sherline mode" in the main setup page (where you set core frequency) this will switch mach3 to a 50% duty cycle on the pulse stream and will fix this issue.

  12. #132
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    Re: Mach3, Mach 4 or Linux CNC for G0704

    I think Jon thought about a motion controller BOB which is a motion controller + BOB all in one which chinese often manufactures and sells on ebay and other places like that.

  13. #133
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    Re: Mach3, Mach 4 or Linux CNC for G0704

    Quote Originally Posted by OlfCNC View Post
    I think Jon thought about a motion controller BOB which is a motion controller + BOB all in one which chinese often manufactures and sells on ebay and other places like that.
    id hesitate to call those motion controllers. they are pulse generators. mach3 is still controling all motion. i can see a pulse generator card with bad synchronisation between axes making some crap cuts. ive avoided those usb cards (including smooth stepper), they tend to be plagued with issues.

  14. #134
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    Re: Mach3, Mach 4 or Linux CNC for G0704

    Yep, but 99.99% of the people call them motion controllers and they are sold on that name, so it is the term what it is called by people and on what name people know these devices.
    Anyways I just wanted you guys know what Jon might thought about when he mentioned "BOB" on that 6040 machine.

  15. #135
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    Re: Mach3, Mach 4 or Linux CNC for G0704

    ive avoided those usb cards (including smooth stepper), they tend to be plagued with issues.
    I'm curious what would you use then?
    The only other option I know about is the LPT port. But in my understanding then the "pulse card" is a PC software module which is very likely to be worse than a microcontroller timed external pulse card.

  16. #136
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    Re: Mach3, Mach 4 or Linux CNC for G0704

    parport i use with mach3. works just fine. only drawback is limited speed and limited number of io. a microcontroller like the avr/arduino cant compete here, nowhere near enough speed to be useful for a fast router, it can indeed control steppers n such... but it so out of its depth on a 3 or 4 axis high speed router or mill.

    on linuxcnc i have a mesa card - which is a high performance pulse generator.

  17. #137
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    Re: Mach3, Mach 4 or Linux CNC for G0704

    parport i use with mach3. works just fine. only drawback is limited speed and limited number of io. a microcontroller like the avr/arduino cant compete here, nowhere near enough speed to be useful for a fast router, it can indeed control steppers n such... but it so out of its depth on a 3 or 4 axis high speed router or mill.
    I see, ok. But LPT port is acient-ware and the thing Windows is not realtime caused me lots of troubles like instantly stopped motion when Windows updates and other softwares kicked in and things like that and jerky unprecise timing pulses.
    With the UC100 motion controller or "pulse card" my steppers can run about 160% faster probably just because the timing is better.
    And I don't think you are correct about the micro or FPGA can't do the same speed, I mean the same amount of information could be throughput on a USB or ethernet connection faster than on an old obsolete LPT port and then that information only needed to be reconstructed back to pulses on a parallel port looking connector or something like that.

  18. #138
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    Re: Mach3, Mach 4 or Linux CNC for G0704

    Quote Originally Posted by OlfCNC View Post
    I see, ok. But LPT port is acient-ware and the thing Windows is not realtime caused me lots of troubles like instantly stopped motion when Windows updates and other softwares kicked in and things like that and jerky unprecise timing pulses.
    hahahah.. no. just, no. you set up the machine to work as a cnc control, not a web surfing box. you turn everything off. ive never seen any for of "windows" issue running mach3.

    With the UC100 motion controller or "pulse card" my steppers can run about 160% faster probably just because the timing is better.
    timing might be better, hard to say. mach does not have the best timing (hence the misses slow pulses i mentioned), but i dont think thats parport related, or mach related. linuxcnc has much better pulse timing than mach3, and its also just software.

    And I don't think you are correct about the micro or FPGA can't do the same speed, I mean the same amount of information could be throughput on a USB or ethernet connection faster than on an old obsolete LPT port and then that information only needed to be reconstructed back to pulses on a parallel port looking connector or something like that.
    you said grbl. that implies arduino level stuff. theres plenty of higher power systems out there for sure, but they dont cost $9.99 on ebay also theres a reason ethernet and usb are not used much and parport is. parport works. sure its slow and limited, but it works. ethernet and especially usb are inherently not realtime. so called realtime ethernet system like my beckhohf ethercat system are not really ethernet as you know it. they use the host tranciever and cable, but its all proprietary protocols. you cant stick your modem or printer on it

  19. #139
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    Re: Mach3, Mach 4 or Linux CNC for G0704

    That foam still puzzles me a bit. Too many of us have machined too many curved things with Mach3 and had really excellent results to just say it's a defect in Mach3. It just does not compute that way.
    On the other hand, foam can be really tricky stuff to machine. You really need to 'keep moving and not stop' if you don't want gouges in the edges. When the cutter stops moving the foam sometimes seems to pull in around the cutter. Very bumpy edges - which is what this looks like.
    Cheers
    Roger

  20. #140
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    Re: Mach3, Mach 4 or Linux CNC for G0704

    hahahah.. no. just, no. you set up the machine to work as a cnc control, not a web surfing box. you turn everything off. ive never seen any for of "windows" issue running mach3.
    Haha, I'm watching vids (Youtube all day long with running the UC100/400 "pulse cards" and never had any problems.

    you said grbl. that implies arduino level stuff. theres plenty of higher power systems out there for sure, but they dont cost $9.99 on ebay also theres a reason ethernet and usb are not used much and parport is. parport works. sure its slow and limited, but it works. ethernet and especially usb are inherently not realtime. so called realtime ethernet system like my beckhohf ethercat system are not really ethernet as you know it. they use the host tranciever and cable, but its all proprietary protocols. you cant stick your modem or printer on it
    Yep, I have one VMC also, that uses EtherCAT, but that is just not the same price range, I mean it is no $9.99.
    And this is why Mach3 "pulse cards" come with plugins running motion buffers, to overcome the non-realtime issues.
    In summary I do not think the problem is with the concept of using a USB or ethernet card, I think an issue can be if one is not properly coded or made.

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