Building a Machine

Hello everyone
New here and new to cnc. Any and all help is welcome.

I would like to build a machine I can do both cnc mill/router and plasma cutting.
This is for home projects, so I do not think I need a big foot print.
I think it will be a 2'x2' machine to start.


I want it to be stiff and strong enough to mill steel, Without over building it.
I was thinking a stationary gantry for x, and a table that moves in the y axis.

So this will have 3 motors xyz, I would like to drive the axis's directly.

For the plasma part of it, It will have a removable water pan that i can mount to the mill table
The z axis will have a mount so I can change between mill head and plasma head.

Some Parts I have.
25mm Square linear rail, The biggest I could afford. Which aren’t as big as I wanted.
Teknic servo motors
CPM-SDHP-3421P-ELN nema34 step and direction
4kw air cool spindle and VFD


Parts needed.
Ballscrews
Looking for a decent driver or break out board.
no Mesa
Pico=maybe
Not sure I will need a driver board for the Feed and speeds on a 2x2 foot machine.
A good BOB is all I may need, I don't know.
Any help here is welcome.

Any design thoughts or considerations is welcome.

Thanks

Andy is correct. Milling requires a stiff (Heavy) structure to deal with the cutting forces. Plasma requires a light structure so that it can provide high speeds and accelerations. Two totally different ends of the spectrum.

For milling steel you will need a substantial structure to be rigid enough. The fixed gantry is probably a good idea for a home-brew machine to cut steel. Even my Grizzly G0619 manual mill does not like steel very much. It is not rigid enough to take a very substantial cut in steel. My CNC mill on the other hand chews it up like candy. 500# machine vs. 6000# machine.

I have toyed with the idea as well but it always comes down to using two gantries. I plan on rebuilding my router in the future and it will be built so that I can use it for routing and plasma but it will have two gantries as the router gantry will be two heavy for plasma cutting without using excessively large drive motors. Lets see if I can catch some wood chips on fire with the plasma!

andypugh wrote:

lincamx wrote:

For the plasma part of it, It will have a removable water pan that i can mount to the mill table

A water pan won't work with a moving-table design, it will slosh on reversals.

Milling steel and plasma cutting have rather different requirements, you could consider two gantries on the same rails/table.

andypugh
Thanks, I didn’t consider that, water slosh.it goes to show that the little thing will get you.

NitroCH3NO2 wrote:

Andy is correct. Milling requires a stiff (Heavy) structure to deal with the cutting forces. Plasma requires a light structure so that it can provide high speeds and accelerations. Two totally different ends of the spectrum.

For milling steel you will need a substantial structure to be rigid enough. The fixed gantry is probably a good idea for a home-brew machine to cut steel. Even my Grizzly G0619 manual mill does not like steel very much. It is not rigid enough to take a very substantial cut in steel. My CNC mill on the other hand chews it up like candy. 500# machine vs. 6000# machine.

I have toyed with the idea as well but it always comes down to using two gantries. I plan on rebuilding my router in the future and it will be built so that I can use it for routing and plasma but it will have two gantries as the router gantry will be two heavy for plasma cutting without using excessively large drive motors. Lets see if I can catch some wood chips on fire with the plasma!

NitroCH3NO2
Thanks
This build is more for milling/routing then for plasma, I know it needs to be rigid, I know I want it to cut steel, how must and how fast not sure,
But it don't have to be fast for a home brew.

I know this is a loaded question.

What IPM min. speed for sheet metal to 1/2 steel for plasma cutting.
I guess it would depend on the pattern being cut also.

There probably a sweet range for cutting, any thoughts on this.

never mind , I found some info

Hello,

I built my own cnc router, plasma cutter, mill and lathe. It is a rack and gear on the x and y axis and ball screw for the z-axis. It is a simple design using square tubing and flat steel with steel v-wheels. I built mine 72" x 72" with 10 " travel for the z-axis. You can build it to any length. I originally used 6" x 8" flat steel for the motor plates and wheel plates but I am changing them to aluminum 10: x 10" for a large machine it is more stable and aluminum is much easier to work with cutting and drilling. I used 1/4" square tubing and there is no flex and it is ridge enough to cut steel. I have been using a 2 1/2 hp router for milling but it has taken a toll on the bearings so I am changing to a 4 kw vdf spindle. My design is easily built with small tools. (drill, hack saw or chop saw and a small welder) The square tubing goes together like a bumper receiver hitch on a truck or car. If you are interested I can post pictures are there is a short youtube video