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CNC Router Build

#1
Well, this is sorta outside of the scope of ORSC but im going to document this here anyway. I made the decision to proceed with a "Large" CNC Rounter build. The goal of this machine is to cut wood(Fiancée wants new cabinet doors..) and possibly 1/4 aluminum plate.

Mechanical Stuff...
I have ordered the Ball Screws, Linear bearings, Anti Backlash Nuts and pillow bearings to began the design. I say begin the design because I'm using CHINA sourced hardware and I dont trust the drawings, so i am going to wait until i get the parts to be certain.

My Ballscrews and Linear Bearing should give me a machine size of ~ 35inches x 55inches. With a work area of something around 29x49. I am essentially going to rip off the design of a existing machine made by a company call Probotix.

asteroid11.jpg

I have a pile of "recycled" 80/20 here at work that I saved from the scrap bin, so that is the biggest reason i am building what i am.

My biggest challenge i see in this project is going to be the gantry supports, these are the beams that tie the base of the machine to top portion.

gantrylwl.png

I will have solidworks models eventually but 3/4 aluminum plate plus machining isn't going to be cheap. So, I am still toying with the idea of 1/2 laser cut steel or using a piece of 80/20 for the upright.

Here are a couple close ups of the Probotix Machines x axis mechanics.
carriagere.jpg
dustcollec.jpg

Spindle
My plan is to use a DeWalt 611 Router for my spindle first. I am using a 660 on my current machine and it hasn't shown any signs of wear, so the increased HP of the 611 and bigger bearings should not hurt. Eventually i might move to a watercooled vfd spindle but its not in the plans for now.

Something similar to this.
y5eme6uz.jpg

For the Motion Control portion, Im planning to use NEMA 23 motors @ 425oz each. This should give me a pretty strong range of motion (2@425oz) with 850oz on the y (long) axis. I might have to upgrade the x at some point but hopefully it will be adequate.
sl500.jpg

Software
I not sure yet which software route im going to go yet. There are 2 major options: Mach 3/4 which is windows based but requires purchase ($175) or Linux EMC CNC (free) both of these use the old school parallel port to bit bang the stepper drivers directly due to the critical timing requirements.
Mach 3
2d34505ced.jpg
Linux CNC
linuxcncfi.png
But has many more custom GUI options.

That just about covers all of the "main" points.

O, Almost forgot. For the CAM software im using a "Demo" version of CAMBAM.
mottola.png
They have a unlimited trial they just limit you to how many launches of the software you use, so I keep it open in a VM and just suspend the VM when im not using it. I will likely buy it if i ever make a buck making something. Its pretty cheap $150.
 
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#4
Ideal surplus in Greenville had a some 3/4" and 1" scrap aluminum sheets. If you take a circular saw with a carbide blade you can cut it and get a small piece for what you need. From there hit up Greenville Rubber and Plastic for the waterjet. Shouldn't be to expensive to just do your gantry supports. Worst case just make the design simple and cut them out yourself.
 
#7
And have my first this isn't going as planned moment.
captureiss.png

The Mounting holes in my Linear Rail aren't going to work with my SAE 80/20 Profile. So now i'm weighing my options.

I could replace the side portions with Aluminum Flat bar 1/2 and add more cross supports.
1246399810.jpg

OR

i could order Metric 80/20. ~ $250 Before our discount here at work and i dont have to cut what i have... Not really sure how i was going to cut what i had, precisely.
 
#8
And the Metric kind sucks too. Id need to mount the rail to a piece of 2 inch flat bar before i bolted it to the frame. Guess that would not be the end of the world.

capturbub.png
 
#9
Do you think the single guide rail on the X is going to be sufficient to battle the torque?
**Edited - Im using 16mm Fully Supported Rail and am still trying to decide how i want to do the y axis.

Well. I hope so, I have a buddy that has one built similar to this, and I am hoping since it will be direct drive on each side that will make up for any flexing. I will use 2 bearing per slide.

There are a few decisions to make on the design of the gantry supports further apart, more "triangulation" but the smaller the use able work area.


The probotix unit specs are pretty similar.

capturepro.png
 
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#13
How many feet of metric 80/20 do you need? May have a way of getting you some scrap but would have to call him.
That could be nice.
This is what i have so far. These are approximations based on the drawing. I don't have my rails yet to have exact measurements.

3 @ ~30in
1 @ ~35in
2 @ ~55in

Using 60mm X 60mm T-Slotted Profile
 
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