big budget cnc

[Desertboy]

I'd extend the frame a little so the gantry can move out the way completely so you can remove the work piece then it's irrelevant which way the gantry is. If you mount the hiwin's and ballscrew on the sides you can enclose them enough that when you access the piece it's not an issue.

Go for 1.6m gantry NOT 3m simple any other choice is just nuts.

[Boyan Silyavski]

if you make the gantry like my gantry/ look at my signature, second build/ it will work perfectly at 3m span.

BUT:

-you will need 3m straight edge, not 2m. So instead of 250euros you are looking at 500-600euros. And nope, you can not build a machine like that without straight edge that spans on top of the longer rails/ Y and A/

-it will weight 250kg. Thatch not a problem but you will need servo motors which are expensive even second hand


Basically you want to build a machine like that so you have smaller machine that could do bigger jobs. Thats the reason for that setup.

I dont understand why is the problem? You only have to load it from side, so just make that side rails lower than the working bed. Thats all.

[pet30]

thats a good idea i would have never thought on raising the bed of the cnc

then i will go for a 1600 mm gantry i think this is the best and strongest .

a beam of 160x80x5 mm will not work then?

mayby it best to take your cnc gantry design then.

can u give me advice on witch steppermotors to use?

[Boyan Silyavski]

thats a good idea i would have never thought on raising the bed of the cnc

then i will go for a 1600 mm gantry i think this is the best and strongest .

a beam of 160x80x5 mm will not work then?

mayby it best to take your cnc gantry design then.

can u give me advice on witch stepper motors to use?

A beam of 160x80x5mm will work with some minor reinforcing.

Make the drawing and then calculate the weight when you are sure thats the final design. Then come the motors.


I greatly recommend doing a machine similar to mine with the changes that Z is simpler, gantry is the beam you have. Reinforce gantry with some additional 60x60 which will serve you to mount the rails . Most of all leave one gantry side raised like mine and simply eliminate other bed side. Instead the rail is lower than table and gantry side is longer. But you will still have the stiffness from the other side.

Below is a quick mock up of what of am talking about. I am not trying to sell you something here, but if you dont have the time or knowledge i can redesign the already proven design to fit exactly what you need, and by doing so you will avoid many possible mistakes on the way. I will help you here for free also of course, but then you have to design all yourself from scratch. Which is a very satisfying experience, but expect much time in understanding all details of a machine.

[pet30]

i made some modifications

the profiles are 80x80x 5 mm think,my metal shop not far from here has got a lot of them.

for the gantry:

a beam of 80x80 then 80 mm high pieces on the beam and again 80x80 beam
on the back of the gantry 80x80x160 mm pieces welded against de total gantry to make it more stronger and less abel to flex.

because i will use r&p i was thinking mouting it on the gantry on top.
then on the sides 1 stepper motor in the steel beam 80x80( to save more space) and 1 just hanging on the bottom against the rack ,
thats mounted against the 80x80 3 meter steel beam.




What do i need to change
the router i will be using in the beginning a bosch router but in the future probably a spindle.
the bosch router ways about 5 kg.

[mekanik]

You could do with modifying the rack mounting arrangement on the the high X axis, it's going to get clogged with debris if you have it as shown.
Regards
Mike

[Davek0974]

Also make the point where the gantry supports join the rails wider and get the spindle centre central to the bed-rail bearing blocks.