Large CNC 1500 x 1500 x 2000 mm - any help ?

Hi,

I want to build a larger CNC for foam milling or other low density material ( wax, milling compound). The precision required is not so strict, 0.5 mm should be fine.

Dimensions are 1500 mm on Z axis, 2000 mm on Y and 1500 on X. Of course, variations are acceptable as long as they do not differ radically.

The parts I want to produce are negatives for large fiberglass parts, milled as blocks, assembled together later and surface finished to an acceptable quality so I can cast a mould onto it. Therefore you understand the precision is not an issue here.

So, if any of you has a clue on how to start this project, and can indicate me a place to download plans, suggest components and can share an advice I will be greatly appreciative and ready to learn.

Many thanks to all of you !

Adrian

Your machine table should be at the floor level. This is in my opinion the simplest frame you can build. But i don't think you will get enough precision with this type of frame. For z=1500 you will get significan vibrations.
http://www.cnc-multitool.com/images/foam-milling9.gif

CNC Styropor Schneidemaschinen und CNC Fraesmaschinen | cnc-multitool GmbH is the site where i found the machine i posted.
As i can see in the picture there are two servos driving x axis, one servo for y axis and two servos for z axis. The guiding system seems to be round + ball screw.

this is an example of screw guiding
http://i01.i.aliimg.com/photo/v0/112...ile_90x180.jpg

I see, the machine looks simple enough, but I imagine that for carving a shape similat to a bath tube for example, it needs to have a very long milling head, or an additional screw that can lower the milling motor so that the carving head is approximative 1000 mm below the frame that connects the two pillars. Otherwise, the travel of 1000 mm on the z axis is useless...

Good observation! This aspect eluded me.
i think it should be something like this:
http://i00.i.aliimg.com/photo/v0/426...ng_machine.jpg
Just machine table must be at floor level and a much higher gantry.
http://www.hendrickmanufacturing.com...-Series/s1.jpg

For this project you must use linear guides.
http://www.nookindustries.com/images/ProfileRail.jpg
In this case yo will need two servos for driving X axis(moving the gantry), one for Y axis and one for Z axis.

A good place to start is Hi-end magazin, Hobby CNC, kituri si materiale
You will find stepper motors, servo motors, drivers, linear guide rails, inverters and so on.
It won't be enough to make a fully functional machine but it can get you started.
First you need to design the mechanical part of the cnc machine but you must also consider the software you will use to generate G-code and what kind of controlers you want to use.
Some popular controlers are Wincnc and Mach3(cheaper).

And there is necessary to have the milling head able to swing along the X axix because the milling motor does not interfere with the milling surface if we have to mill a vertical wall for example XZ plane. And around the Z axis for the vertical wall in the YZ plane. Huh, this does not seems to be an easy task...

Maybe you projects require 4 axis(c axis) 360 degrees rotation agregate with manual adjusting milling angle or 5 axis( like the Hendrick machine in my earlier post).
I belive you want to build something like this CNCMotion machine:
http://www.cncmotion.com/titancanada3.jpg

5 axis definitely... I wonder how are the german machines milling a near vertical wall, the ones in the first example you gave me... I'll send them an enquiry...

I plan to do the same, but with lower Z-travel.
http://www.cnczone.com/forums/open_s..._cost_cnc.html

Quote:

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Originally Posted by KTM

5 axis definitely... I wonder how are the german machines milling a near vertical wall, the ones in the first example you gave me... I'll send them an enquiry...

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I'm not sure i understand what you mean with near vertical wall milling. But if i'm correct you should solve the problem by making the machine x and y axle travel bigger in order to be able to lower the 5 axis spindle on any of the processing foam parts 4 sides. it's also wise to consider maximum tool length and diameter.

I hope you understand how much building/buying a 5 axis machine will cost...

I am not sure about the costs, but I hope I will have an idea by the end of the week :)

Longer tool means vibrations if it is eccentric. Bad vibrations :)

Dismantle of the model in several panels might be a solution, but sometimes it is a puzzle too big to support itself, that is why I preferred the blocks, but if the budget is too high, might be a solution.

I am glad I found a starting point, this forum, makes me hope I will see the end of this line sometime :)

I have found this:

5 AXIS CNC Router or Mill Stepper Motor complete kit | eBay

it is a 5 motor controller for a 5 axis router, looks like all that remains is to understand the principles and build the gantry. One step closer...

and even better, this:

5 Axis Nema 34 stepper motor 878 oz.in CNC Router/Kit | eBay

it is a bigger torque motor kit, 6.2 Nm, meaning there is a bigger gantry that can be moved by these small devils...

The second one is likely a better buy, than the single board.
You may have noticed that one kit offers 5 motors with 3 A per phase operating off one 350 Watt power supply (this will not work). The other 2 power supplies 350 Watt each for 5 X 878 oz motors may be not enough either.

KTM, i'm sorry but i don't think any of those kits will work for you.
For your project you need to control 6 axis like following:
- X+A for moving gantry on x axis
- Y
- Z
- C (360)
- B (+-90 degrees)

You need a 2 axis spindle head (C and B axis servo motors on the spindle)

That's all correct, except A axis, I don't need that because B&C axis is sufficient freedom for my needs. Also, considering I will be running this project so complex now I am planning to extend the X axis to some 5000 mm, the Y to a 2500 and the Z to some 1500-2000. The difference will be in the framework and some screws ( or belts ) but it will reach a pro level.