Re: [CAD_CAM_EDM_DRO] Which is the best election for...?

I ll be glad to help, as far as I can.
Now finalising (Makeing) a mill ! of almost same size (1400x2400x400 mm).
My project has taken over 1000 hours, and 3 years, and 3.000 $.

You should have some basics and well be able to help better -
How much can you spend ?

How much is your time worth ? - How much speed do you need ?
How much can you build ? Whats skills/tools do you have ?
How much time /work can you put in this ?

The best option if you can decide on whether you wish to build the machine
or use the machine, and how much you want to build yourself.

If you build most of it,
can get slides cheaply (Thats a BIG if ?),
you may get by with about 1000 $.

0,5 mm is very easy, if you buy slides.
Look for hiwin (cheapest, good), about 25 mm thickness.
Theyll cost you over 1000 $ alone.
(2 blocks on each slide, 2 slides on each axis).

Is this too much ?

Rack/pinion for driving the gantry is about 3-600$, depending.

Pulleys, 100$. You should bore them for your steppers shaft size, can
you do this or get it done ?
Otherwise, add accurate couplers, about 150 $. Look for something like
e.g. oldham couplers.

PSU; Can you build this ? It's not very difficult, if you have done some
eletronics work/hobby.
You need about 60-80V DC, 1500 VA.
There are several schema/drawing available.


Linear slides; hiwin, thk, or possibly bishop visecarver rollers and
slides.
I would recommend that you buy them, unless you have acces to and skills
in precision metalworking.
Milling large, accurate slides may be too involved.
Having said that, I am building my own slides - commercial slides would
cost me over 2-3000 $- can't afford it.

Some recommendations follow; no commercial interest.
Some consensus figures and good providers for your project;
Dan Mauch, steppers and servos; get steppers, about 400-600 oz-in.

If your budget allows, you may wish to get servos for faster speeds.
It will make it (slightly) more complex. Maybe 500 $ more overall.

Get/make a PSU of about 60-80 volts, about 20 times your steppers max
voltage.
You max voltage is 80 V with gecko.

Get gecko drives from www.geckodrive.com

Get two optoisolated breakout boards from, e.g. cnc4pc.

Ge some big red emergency stop buttons, some relays to turn off your
stuff in an emergency,
mach3 sw to drive the hw from art fenetry of artfcnc.com,
rhino3d to design the parts/work, maybe meshcam for 2.5 d stuff.

Gear down about 2:1 or 3:1.
Use timing belts and pulleys, about 10 mm wide belt.

Get a gas spring to support the head. On a big router like yours, the
head will be heavy.

You can make the structure /frame from almost anything.
I would recommend a welded steel structure. Even wood would work, and
some people have used it.
I am using a mixture of welded, pre-loaded steel structure, with torsion
boxes, and concrete for ballast/balance/mass/stiffener.
My structure weighs over 800 kg.

Aluminium thermal expansion will be greater than you think, and I would
recommend against extruded aluminium.
It will affect your accuracy, over 2800 mm.

Good luck, and welcome to the group.
Best Hannu

thunder2kal wrote:

>
> Hi to all,
>
> Can somebody help me?
>
> I am to begin the design and the construction of a workshop-made
> cutting-milling machine of the following dimensions: 2800 x 2000 x
> 100 mm (9' x 6.5' x .3'), for wood (MDF), with a precision of, at
> least, 0.5 mm (0.02").
>
> I don't have experience in the matter, for what I appeal you so that
> suggest me the best alternatives from the point of view of the
> relationship cost-benefit in the following aspects:
>
> In other words: That you would use in each one of the aspects of the
> machine?
>
> 1) Table/bases/supports
> 2) Lineal movements/joinings
> 3) Motors
> 4) Electronic drivers
> 5) Software
> 6) Other aspects that consider important
>
> Any advice is very important for me!
>
> Thank you in advance.
>