need help! choosing right kit

[Boyan Silyavski]

of course you can estimate weight of gantry

cross-section of 100mm x 3mm box section is 100*100-94*94=1164mm^2
gantry is 1350mm wide approx. so total volume of steel is 2 * 1350 * 1164 = 3142800mm^3 = 0.0031428m^3 @8750kg/m^3 = 27.5kg
add spindle, carriages, energy chain, y & z stepper, ballscrew/rack, y-rails, z-rails, etc. (all of which you can get from data sheets or calculate), and your gantry is in the order of 50kg which is typical. add 30% safety margin and for sizing purposes use say, 65kg. - its good enough to help decide what motor is needed.

Just saw his build and did not pay attention here

He is looking at best case scenario of 100x100x3 9kg/m, just checked it, so the gantry with sides depends how he will go having in mind 300mm Z , will weight minimum ~50kg without z and rails!!!

The Z will weight around 30kg + all the rails and motors and so . Especially if he wants a sturdy machine. The lightest gantry possible as i see it is more or less the way i make it right now on my build here and is not light at all.

My conclusion for my build was to go with servos or nema 34 to be on the safe side. i went with servos.



Another point is that Rack and pinion is not the best solution so better continue at his build thread, as all is interconnected.


msacnc,

Its wise first to finish the design, then to decide the motors. Rotating ball nut on long axis will be better option. Coupled with 2510 ballscrew on your machine size.