Building a homade CNC

[lefteris_]

Hello everyone!!

I'm thinking of building a cnc and i would like your help.I believe tha it is not that hard since there are many kits and ready products for that reason.

I would like your opinion for the cnc kit bellow.

http://www.ebay.com/sch/i.html?_trksid=p4634.m570.l1313.TR0.TRC0&_nkw=3+axis+cnc+kit&_sacat=0&_from=R40

For the sliding of the moving parts i'm thinking of using drawer sliders,it's a good solution.

I will make the frame using mdf.

For the design of the parts im using google sketch up with the free plug in sketchupucam for generating the g-code.

So, lets discuss about this!

[kam]

Well, here is a nice post! 

The motors seem strong enough, although those ebay items look so much better in the photos...

As for the slides, i'd rather recommend you get some real rods and roller bearings. They are not extremely expensive. Google for chris motors (Greece, Spirou Patsi) and ask for cylindrical bearings and 10mm steel rods. They come together with clamps and bases. I can guarantee that drawer mechanisms will give you a headache. At the end, you will pay like 400 euro and have 1mm precision, which sucks big time.

PLUS::: DO NOT even search for these bearings in ebay. I already got 2 pairs for a drill press. They SUCK. The drawer mechanisms are better

So, what's the idea behind the CNC? Is it a drill? I cutter? Both? And what about the software?

[lefteris_]

So the kit is not so good?Do i need anything else tha it is not provided by the kit in order to operate the cnc?like motor controlers?Becouse im a bit confused...

I'm trying to collect as much info as i can in order to built it,step by step till the end.

I found some rods and linear ball bearings

http://www.ebay.com/itm/1pc-OD-10mm-x-400mm-Cylinder-Liner-Rail-Linear-Shaft-Optical-Axis-/290765606501

Are thease the bearing that you bought?
http://www.ebay.com/itm/SC10UU-SCS10UU-Linear-Ball-Bearing-Motion-Bearing-CNC-/110739289341

The cnc kit comes with the mach 3 software.

It's a drill cnc!!

[kam]

what do you plan to make really? What sort of cnc? cutter? drill? laser? draw?

For the kit, i just said that i had bad experience from ebay items. this one may differ. Google the net as well before you go and buy it.

For the bearings - These are the ones that i'm talking about. Exactly. But do yourself a favor and do NOT get them from ebay. they have absolutely no precision. Better go with the drawer mechanisms. They have the same precision and they are cheaper.

Also, let me suggest a good quality plywood (in Greek: kontra plake) and not MDF. MDF has this bad habit to crack open when you screw its sides. Plus, it absorbs moisture like sponge(bob)., You have to paint it very well to seal it from moisture, otherwise it will eventually become thicker at the edges.
Plywood is much better. A good quality plywood (which is a little bit more expensive than MDF) does not bend and does not absorb any moisture at all. I tested one piece of plywood 3 years out on the direct sun-light, rain and cold. It bended just a little bit (almost nothing) but it did not crack open. Only the side facing the sun became darker.

[cheerio]

please post updates on this project
smth like this is on my wantlist too

[lefteris_]

hi cheerio!

Well, if this is on your wantlist we could help each other and find the best parts and build a very good homade cnc!!

@kam

I want to dig in mdf so this is called drill cnc?Basicly this is going to be a cnc for wood!

For the bearings-What do you mean that they have absolutely no precision?The shaft sould slide inside the bearing smooth and effortless thats all.

Now im serching the net for parts and hardware.

I still believe that building a cnc is easy!!

[George]

This CNC reference may be worth a read for your research

http://www.probotix.com/FireBall_v90_cnc_router_kit/

Cheers

[kam]

I want to dig in mdf so this is called drill cnc?Basicly this is going to be a cnc for wood!

So you're going for a router!

For the bearings-What do you mean that they have absolutely no precision?

You place two bearings, you put the shaft inside, and the shaft is still free to move. This means that if you use those cheap ebay bearing, your router table and the router itself will have vibrations and they will not be stable.


Regarding the link from George... There has to be an explanation why the use MDF... I mean, why not using OSD or plywood. They are so much stronger.