Sturdy and Fast all Steel CNC , my first build

[Boyan Silyavski]

Hi,
All pulleys and belts are from beltingonline.com
Nothing special, ball screws machined normally. 2 grub screws on pulley. A drop of instant glue on the shaft. If I was doing it for myself i would file or drill the shaft where the grub screws are. Now it's more forgiving for mistakes

On the big machine I am building now for myself I use only aluminum pulleys as it would be geared 20:30 t and the rotating nut is heavy so I don't want to have too high inertia. These I bought from China as here prices are prohibitive. Aliexpress.

Normally you don't need any special machining given that the motor plate is not thicker than 10mm.
On the Z however is good idea not to make it too strong especially if geared for some reason. Cause hitting the bed can do some damage especially with strong motor.

[HipoPapi]

Hi,

Thanks for the info. I am thinking 3 to 1 on X and Y and 2 to 1 on Z as my Spindle will be large about 15 kg. I see they offer grub screw and key cutting service as well so will have key cutting on the servo side and grub screws on the ballscrew.
I understand from your info given ( 20:30) that you calculate the gearing ratio by the tooth count?

I see you are using on your new machine the west systems 105+209 wich I know is ideal for this application the only problem beeing that here in the uk the weather isn't ideal :) Do you think I will be ok with the 105+207 or 206?

Thanks again,
Vass

[Boyan Silyavski]

Hi,

I understand from your info given ( 20:30) that you calculate the gearing ratio by the tooth count?
Vass

Yes, cause 1:2 , 1:3 or whatever seems not to reflect reality , misleads the mind. The reality is that 16t is the smallest one and geared 1:3 means 48t for the second one which is in fact 75.25mm in diameter and at 100mm separated center from center they have only 6t in mesh. So imagine the inertia if from steel. Even from aluminum.

I assume you will be using servos. So the encoder count + ballscrew pitch will dictate your gearing, as it will determine resolution, max speed of the machine.

I see you are using on your new machine the west systems 105+209 which I know is ideal for this application the only problem being that here in the uk the weather isn't ideal :) Do you think I will be ok with the 105+207 or 206?

Thanks again,

No, it will be a problem. Its not only the time, the faster it cures the more heat generates, the more it distorts. Whats the problem with the weather in UK? humidity is not a problem if its not raining directly on it. And where i live its much more humid.