Need Help!- Help with preload for linear guideways? thanks

[luis81]

For a milling machine for metal (aluminum, brass and copper) with linear guide QHH20CA Hiwin which is the most recommended preload Z0 or ZA?
Thanks

[luis81]

help !!! thanks

[judleroy]

I would think (and i'm not an expert) that for the materials your cutting you will be fine either way.

[luis81]

milling machine no cutting machine

[RICHARD ZASTROW]

luis81, Here in the USA, milling, drilling, lathe turning, etc. are all referred to as metal "cutting". Just a small language problem.LOL

Dick Z

[mactec54]

luis81

Your answer is to use the ZA The Z0 is to free & only has a very light preload almost zero

[luis81]

Originally Posted by mactec54 luis81 Your answer is to use the ZA The Z0 is to free & only has a very light preload almost zero

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For fear that a medium preload was too I have already orderd carriage with light preload but I picked up the ball cage model. I will not use cutters more than 10 mm in diameter.

The model carriage is:

QHW20CCZ0H

static load 25630N = 2615 Kgf
dynamic loading 23080 N = 2355 Kgf
Preload (0 to 0.02)>> 23080x0.02 = 461.6 N = 47.10 Kgf

I will use 4 for each plane, therefore

Total Preload

47.10 Kgf* 4 carriage = 188 kgf for plane


Do not know if this will be good or bad. What do you think? thanks a lot

[mactec54]

luis81

The Z0 will work for light milling, but they won't dampen the vibration that happens when milling steel as well as the ZA will, see if you can change your order

[luis81]

Hello mactec54,
I can change the order but I have doubts, so I will provide more data on my cnc project.

The configuration I want to do is like the machine you see in the picture below.





My gantry weighs approximately 32 kg
For ballscrew I'll buy it on ebay, chinese ballscrew diameter 20 mm and 5 mm pitch.

If I choose a large preload the ZA then the total preload would be approximately 471 and 659 Kgf but I think it can be much.

In this case how much force should have a minimum motor for normal operation? Don't need high cutting speeds. Thanks a lot

[luis81]

_

[luis81]

Originally Posted by mactec54 luis81 The Z0 will work for light milling, but they won't dampen the vibration that happens when milling steel as well as the ZA will, see if you can change your order

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My gantry Weighs Approximately 32 kg. For ballscrew I'll buy it on ebay, chinese ballscrew diameter 20 mm and 5 mm pitch.

If you choose half guides preloaded total theoretical preload would be between 471 and 659 Kgf. With AC servos from DMM Technology :

High Torque Brushless AC servo motor
Rated torque: 2.9 Nm(409 oz-in), peak torque: 7.2 Nm(1015 oz-in), Max Speed >1000rpm, Peak power 900W.

Would be sufficient to obtain optimum speed connecting them directly to the shaft ??. I do not intend to obtain large cutting speeds. Thanks a lot

[mactec54]

uis81

I will see if I can do some tests, I have some Z0 & ZA bearings, for 20mm rails