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  1. #121
    Quote Originally Posted by CharlieRam View Post
    Yes. You would have to spin the ballscrew twice as fast as a 1610 to achieve the same linear speed

    Sent from my XT1072 using Tapatalk
    yes machine is already setup to just do that, as I mentioned speed is fine, motor stalls If I increase acceleration to higher than .5m/s^2 range

  2. #122
    But because the motor is spinning faster it will have less torque than the same motors in the other axis

    Sent from my XT1072 using Tapatalk

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  4. #123
    Quote Originally Posted by CharlieRam View Post
    But because the motor is spinning faster it will have less torque than the same motors in the other axis

    Sent from my XT1072 using Tapatalk
    thanks that makes sense! but makes me sad haha

  5. #124
    Quote Originally Posted by Noplace View Post
    yes machine is already setup to just do that, as I mentioned speed is fine, motor stalls If I increase acceleration to higher than .5m/s^2 range
    If you take the belt off the Z-axis and give it a slight push, does it start moving down by itself due to gravity? If not then your ballscrew and or rails may not be aligned well.

    To increase the acceleration capability the easiest way is to change the drive ratio. Make the pulley on the Z ballscrew larger, or the motor pulley smaller. The torque required for acceleration is proportional to the inertia reflected to the motor. This inertia scales with the drive ratio squared, so if you make the ballscrew pulley half the size, the motor will see about 1/4 of the inertia as before and the torque goes down by the same ratio. It's not quite as good as that as the larger diameter pulley will have a higher inertia, but you'll also reduce the torque required due to friction and lifting the axis (though that is already small).

    Once you think the motor tuning is correct, I recommend running random g-code rapid moves for say half an hour, as that will stress the system to give confidence that the machine will not stall. I've made a spreadsheet here to do it:

    http://www.mycncuk.com/threads/5843-...g-motor-tuning
    Old router build log here. New router build log here. Lathe build log here.
    Electric motorbike project here.

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  7. #125
    Guys quick question, filling up the steel tubes, is it worth it? can I use normal concrete for that? any disadvantages?

  8. #126
    I think kiln dried sand (as used for block paving) is the preferred thing to fill with for resonance. That way if you put bungs in you can empty it should you wish to move the machine...
    Neil...

    Build log...here

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  10. #127
    Quote Originally Posted by Noplace View Post
    Guys quick question, filling up the steel tubes, is it worth it? can I use normal concrete for that? any disadvantages?
    What's in Concrete that doesn't mix well with Steel.?? . . . Neil's suggestion is spot on and yes it's worth it.

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  12. #128
    Neil is correct, problem with creat is it can become brittle and brake up/crack, when that happens you end up with "lose" in your tubes and so on.

    We used to call it silver sand back in my paving/block driveway days, think there is a difference between it and kiln dried, silver being a finer grade as it needs to work it's way into all the joints on the blocks.

    .Me
    .Me

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  14. #129
    Quote Originally Posted by JAZZCNC View Post
    What's in Concrete that doesn't mix well with Steel.?? . . . Neil's suggestion is spot on and yes it's worth it.
    Umm are you talking about water? :p

  15. #130
    Quote Originally Posted by Noplace View Post
    Umm are you talking about water? :p

    When the steel is in something without oxygen there is no problem rusting. Otherwise all the bridges will fall down.



    As for the cracks cement for table tops or for workshop floors, it has additives, polymers, not to change size or crack
    project 1 , 2, Dust Shoe ...

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