New Build 1000x600x200mm (newbie)

[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?

[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.

[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

[Noplace]

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

I see epoxy granite is mentioned a lot also online, what do you think of it? also do you have an example of a cement product for table tops/workshop floors so that I can check locally whats available?


EDIT: also what about UHPC, I highly prefer something that would be permanent instead of grain/sand structure that's why I'm asking about these options instead. thanks!

[njhussey]

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

Yes but the steel in bridges is normally reinforcing and therefore encased in concrete so no air can get to it, if done properly that is! Here we're talking about encasing concrete with steel, there's got to be a hole in to pour the concrete (and for air to escape) and therefore there's a way for air to get in. Now if you could pour it in a vacuum......

[JAZZCNC]

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

Different ball game and the steel is coated and protected before concrete is poured. The steel is also encased in concrete not the other way around.

[Neale]

...or the bridge is built from Cor-Ten steel which is allowed to weather and build up a rust-based patina that coats the surface and prevents further corrosion. Not many routers built of that, though!