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Re: Sherline CNC RT settings....

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  • Ron Ginger
    ... Just pick some number and try it, say 10 ipm. jog the machine back and forth and listen. If its nice and smooth sounding, raise the number a bit and try
    Message 1 of 10 , Mar 14, 2009
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      >
      > I too would like any info on Velocity and Acceleration on all the axes. I
      > know that it depends on voltage/motors/power supply etc. but where to start
      > first?
      >
      > Do you write a G-code stress test and measure for incorrect positioning at
      > the end?
      >
      > Hamilton
      >

      Just pick some number and try it, say 10 ipm. jog the machine back and
      forth and listen. If its nice and smooth sounding, raise the number a
      bit and try again. When you are too high its going to growl and buzz
      like mad. Lower the number by 10% or so and try again. Same with
      acceleration.

      You want to wind up with the highest numbers that are solidly reliable.

      After you have some speeds that seem reasonable you need to make some
      accuracy measurements. Set up an indicator and make an exact move using
      the MDI input. Dont try to run a program things will change to fat. Just
      test one move- G01 X1, then G01X0 back and forth. When you are sure its
      right do the same for Y and then Z.

      It takes some time and feel. The final speed numbers will depend on lots
      of variables of your machine, like how tight the gibs are, how well
      things are aligned, etc. You cannot put much trust in numbers that
      others get.


      The exception is the number of steps per inch (or mm). This is NOT a
      tuneable number, it is a mathematical constant based on your lead screw
      pitch, motor steps per rev, micro stepping of the drive. You must
      calculate a proper value and use it.

      ron ginger
    • Hamilton Elliott
      Hi Ron, Thanks for that information but as usual prompts more questions ;) Michael was wondering about a rotary table, is it the same for that or would you
      Message 2 of 10 , Mar 14, 2009
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        Hi Ron,
        Thanks for that information but as usual prompts more questions ;)

        Michael was wondering about a rotary table, is it the same for that or would
        you just try to run it slower?

        I asked about a stress type test because I thought that using more than one
        axis at a time might cause the system to lose steps where one axis on its
        own would be OK? Again you could get it to return to a fixed point to
        compare it from where it started?

        I have seen some of your posts on the Mach3 forum so I know that you use it?
        I have not seen much code/macros etc for use with a rotary axis. Is it
        (4th)normally used on its own to just rotate the part between sessions of
        "ordinary" XYZ machining?


        Thanks again for your patience with newbie questions.

        Hamilton



        -----Original Message-----
        From: SherlineCNC@yahoogroups.com [mailto:SherlineCNC@yahoogroups.com] On
        Behalf Of Ron Ginger
        Sent: 14 March 2009 17:18
        To: SherlineCNC@yahoogroups.com
        Subject: [SherlineCNC] Re: Sherline CNC RT settings....

        >
        > I too would like any info on Velocity and Acceleration on all the
        > axes. I know that it depends on voltage/motors/power supply etc. but
        > where to start first?
        >
        > Do you write a G-code stress test and measure for incorrect
        > positioning at the end?
        >
        > Hamilton
        >

        Just pick some number and try it, say 10 ipm. jog the machine back and forth
        and listen. If its nice and smooth sounding, raise the number a bit and try
        again. When you are too high its going to growl and buzz like mad. Lower the
        number by 10% or so and try again. Same with acceleration.

        You want to wind up with the highest numbers that are solidly reliable.

        After you have some speeds that seem reasonable you need to make some
        accuracy measurements. Set up an indicator and make an exact move using the
        MDI input. Dont try to run a program things will change to fat. Just test
        one move- G01 X1, then G01X0 back and forth. When you are sure its right do
        the same for Y and then Z.

        It takes some time and feel. The final speed numbers will depend on lots of
        variables of your machine, like how tight the gibs are, how well things are
        aligned, etc. You cannot put much trust in numbers that others get.


        The exception is the number of steps per inch (or mm). This is NOT a
        tuneable number, it is a mathematical constant based on your lead screw
        pitch, motor steps per rev, micro stepping of the drive. You must calculate
        a proper value and use it.

        ron ginger


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      • Tom Hubin
        Hello Hamilton, ... I have a Sherline 5410 CNC mill with a PMDX 4 axis driver (only 3 axes installed). I use TurboCnc on a 200MHz Toshiba Satellite laptop for
        Message 3 of 10 , Mar 15, 2009
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          Hello Hamilton,

          > I too would like any info on Velocity and Acceleration on all the axes. I
          > know that it depends on voltage/motors/power supply etc. but where to start
          > first?

          I have a Sherline 5410 CNC mill with a PMDX 4 axis driver (only 3 axes
          installed). I use TurboCnc on a 200MHz Toshiba Satellite laptop for
          machining. I use Mach3 on an 800MHz Dell Inspiron laptop for some
          experimental work. I have dual axis steppers with dials left on so I can
          use manually.

          The steppers are double stacked and rated for 200 oz-in. The system does
          not run much faster than when I had the Sherline factory steppers.
          However, I have managed to break more things, including the x axis
          coupler.

          I can run all of my axes at 20ipm rapid. However, I have to keep
          everything clean and lubricated and adjusted to do this. Just a little
          friction can make it skip steps. I don't do any production work so rapid
          speed is really not important to me so I usually set all three axes for
          10ipm.

          Acceleration is also unimportant for non-production work and high
          acceleration is often problematic. So I set my acceleration to reach
          full speed in 1 second.

          Both of these values should be achievable on a Sherline unless you have
          weak steppers or low voltage electronics.

          Using multiple axes makes no difference unless your drivers cannot power
          multiple axes simultaneously. That would be unusual.

          Perhaps you should give us more particulars about your system. Which
          Sherline model and how old and how used (history and present)? What
          brand stepper motors and what voltage, current, torque? What electronic
          driver? What software (EMC, TurboCnc, Mach3, other)? What computer type
          (i.e. laprop, desktop) and clock speed?

          Some of our answers will depend on the combination of items above that
          you happen to have.

          And then, just for fun, what do you plan to make with it?

          Tom Hubin
          thubin@...
        • Hamilton Elliott
          Hi Tom, Thank you for your comprehensive reply. You may have realised from the question that I am a complete and utter newbie!! If fact so much so that I
          Message 4 of 10 , Mar 15, 2009
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            Hi Tom,
            Thank you for your comprehensive reply. You may have realised from the
            question that I am a complete and utter newbie!!

            If fact so much so that I haven't got a mill yet. It is ordered, but hasn't
            arrived. I am in Ireland so getting things delivered takes a bit longer. I
            have ordered almost a month ago through the Swedish distributor which also
            adds to the time. He gives a good deal on the shipping charges so it is
            worth the wait.

            I have ordered a 5410A-CNC-CE with the CNC ready rotary table.
            I have a Gecko 540 which came very quickly and at very reasonable shipping
            $25.00
            I have 4 KL23H284-35-4B steppers @ 387 oz in Static also arrived quickly @
            $69.95 shipping
            Also a KL-350-48 48Volts 7.5Amp power supply
            The computer I had spare. I tried a faster Toshiba laptop than yours but
            unfortunately wouldn't work with Mach3. (no EPP parallel port) so the
            desktop is a 1.8GHz just for Mach3.
            My plans are to use the setup to make accessories for Steadicams for video
            (broadcast quality). I am also involved in video production but not at
            broadcast quality level. I also want to make fun projects like Sterling
            engines etc.

            So if you can imagine I have the CNC bit all set up with the steppers in a
            line on the table with no mill, very frustrating. While I wait for the mill
            I have been reading the CNC and Mach3 forums trying to glean useful
            information.

            Because of my programming experience I am interested in wizards and macros
            in Mach3 and I would hope to write a few when I get more experience with
            milling.

            Because a lot of the info I have read is about big mills or routers I felt
            that other Sherline users would be the best source of basic knowledge of
            where to start setting the configuration settings.

            The examples you have given are great because they apply to Sherline and
            give me a real idea of what to expect.


            Many thanks,
            Hamilton


            -----Original Message-----
            From: SherlineCNC@yahoogroups.com [mailto:SherlineCNC@yahoogroups.com] On
            Behalf Of Tom Hubin
            Sent: 15 March 2009 11:57
            To: SherlineCNC@yahoogroups.com
            Subject: Re: [SherlineCNC] Sherline CNC RT settings....

            Hello Hamilton,

            > I too would like any info on Velocity and Acceleration on all the
            > axes. I know that it depends on voltage/motors/power supply etc. but
            > where to start first?

            I have a Sherline 5410 CNC mill with a PMDX 4 axis driver (only 3 axes
            installed). I use TurboCnc on a 200MHz Toshiba Satellite laptop for
            machining. I use Mach3 on an 800MHz Dell Inspiron laptop for some
            experimental work. I have dual axis steppers with dials left on so I can use
            manually.

            The steppers are double stacked and rated for 200 oz-in. The system does not
            run much faster than when I had the Sherline factory steppers.
            However, I have managed to break more things, including the x axis coupler.

            I can run all of my axes at 20ipm rapid. However, I have to keep everything
            clean and lubricated and adjusted to do this. Just a little friction can
            make it skip steps. I don't do any production work so rapid speed is really
            not important to me so I usually set all three axes for 10ipm.

            Acceleration is also unimportant for non-production work and high
            acceleration is often problematic. So I set my acceleration to reach full
            speed in 1 second.

            Both of these values should be achievable on a Sherline unless you have weak
            steppers or low voltage electronics.

            Using multiple axes makes no difference unless your drivers cannot power
            multiple axes simultaneously. That would be unusual.

            Perhaps you should give us more particulars about your system. Which
            Sherline model and how old and how used (history and present)? What brand
            stepper motors and what voltage, current, torque? What electronic driver?
            What software (EMC, TurboCnc, Mach3, other)? What computer type (i.e.
            laprop, desktop) and clock speed?

            Some of our answers will depend on the combination of items above that you
            happen to have.

            And then, just for fun, what do you plan to make with it?

            Tom Hubin
            thubin@...
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