Need Help!- Ballscrew 1610 2m

[kostas1]

Hi,
well, I purchased the follwing ballscrews from Chai: one 1800mm 2510, one 1200mm 2510, one 400mm 1605 for 3 axis, one ballscrew in each axis...
Do you think that one ballscrew will can handle the 1800mm length, given that I rotate screw?
Would it be better to also add a second ballnut to the longest ballscrew (x) so as to make it more stable?

What do you think/predict?

Kostas.

[TSJ]

If you rotate the ball nut why can't you just mount the motor to the gantry (using good techniques for cable management), attach a timing pully to the nut and motor and spin the nut with the motor. You have to lock down each end of the ball screw and support the ball screw at the gantry. If you have a problem with the belt you have to disassemble half of the ball screw attachments. I must be missing something, what will take 12 weeks.

[marchantdice]

Your going to have problems rotating a Chinese Ballscrew assembly...
I'll be honest you will have 2 problems....
1. what we call high and low
2. rotating ballnuts are usualy high helix 20x20, 25x25, 32x32 and 40x40

a second ballnut, this will not help you resolve issues with speeds...

Originally Posted by kostas1 Hi, well, I purchased the follwing ballscrews from Chai: one 1800mm 2510, one 1200mm 2510, one 400mm 1605 for 3 axis, one ballscrew in each axis... Do you think that one ballscrew will can handle the 1800mm length, given that I rotate screw? Would it be better to also add a second ballnut to the longest ballscrew (x) so as to make it more stable? What do you think/predict? Kostas.

[marchantdice]

The rotating ballnut must be housed, that is to say you must not fix a pulley directly to the ballnut....bearings must be fitted around the ballnut within a housing, the housing can then be assembled with a toothed pulley...the motor is then fixed to the frame / gantry...

Originally Posted by TSJ If you rotate the ball nut why can't you just mount the motor to the gantry (using good techniques for cable management), attach a timing pully to the nut and motor and spin the nut with the motor. You have to lock down each end of the ball screw and support the ball screw at the gantry. If you have a problem with the belt you have to disassemble half of the ball screw attachments. I must be missing something, what will take 12 weeks.

[kostas1]

Ok guys,
I am a little confused...we also have to have in mind the cost...

1) So if I go to rotating ballnut,how does this cost?

2) Also,what I am going to do with the machined ends of ballscrews in case that I will put rotating nut?Do the machined ends be useless then?

3) An option would be to buy an extra ballscrew,motor,driver to have two screws in the long axis that will move the gantry...is this approach more economic than putting a rotating ballnut and changing the ballscrews I already purchased?

4) Nook industries calculators show that I can have critical speed 2080RPM when using 25mm diameter ballscrew in a length of 1800mm and fixing type=D...So where is the real problem? Will it rack in the edges and don't have clear cuts near them?

Guys, it is really confusing and complex as I have had no experience before...I need a true explanatory guide on this...
Thanks,
Kostas.

[marchantdice]

Purchase an additional Ballscrew Assembly...you can either link the stepper motors in Mach3 or connect 2 stepper motors to 1 driver (not a reccomended method) but if you want a 4th axis this method will leave a free socket?

[kostas1]

Hi,
no,I will have 3 axis only...
This image you attached is the rotating nut right?
It seems that I cannot use it since:
1) I already purchased machined ballscrews ends
2) I will buy extra set of motor/driver/screw?

Will I have problem with the existing KL-6515 power supply, the C11 break out board and the connections?

Thanks,
Kostas.

[kostas1]

Hi,
I finally decided to go with one ballscrew in the middle of the gantry, but I made a trade off:I widen the gantry upright sides to 25cm and now I am thinking if It is better to make it 30cm...By widen the gantry upright sides, any racking possibility is minimized right?

Kostas.