New Build 1000x600x200mm (newbie)

[Noplace]

Yes. You would have to spin the ballscrew twice as fast as a 1610 to achieve the same linear speed

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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

[CharlieRam]

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

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[Noplace]

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

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thanks that makes sense! but makes me sad haha

[Jonathan]

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

[Noplace]

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

[njhussey]

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...

[JAZZCNC]

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.

[Lee Roberts]

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

[Noplace]

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

[Boyan Silyavski]

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