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My new CNC - COMPLETED

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LAN_403

Dr. H.

Mon Jul 12 2010, 06:46PM

Registered Member #931 Joined: Mon Jul 30 2007, 05:25PM
Location: Bulgaria
Posts: 486

Good day guys

First - I know this is not a mechanical forum but still - it is my favourite place to post so here goes...

Some of you might have seen my old crappy CNC. Its purpose was educational rather than actually doing work, but I've used it for more than 1 year... and it was finally time to start building a new one.

Here are some pics of the progress - the Z axis is pretty much done. The only thing missing is the spindle. It uses 12x3mm leadscrew and teflone-graphite nuts. We've made a "tapper" from a piece of the lead screw.

I've been also working on the electronics for quite a while now.
Pics: servo motors, tapper, Z-axis and X- linear guides and assembly

Cheers

Linas

Mon Jul 12 2010, 06:51PM

Registered Member #1143 Joined: Sun Nov 25 2007, 04:55PM
Location: Vilnius, Lithuania
Posts: 721

It looks like real deal, nice job
Really impressive, solid look :)

Dr. Drone

Mon Jul 12 2010, 07:33PM

Registered Member #290 Joined: Mon Mar 06 2006, 08:24PM
Location:
Posts: 1673

Anon01

Mon Jul 12 2010, 10:38PM

Registered Member #1589 Joined: Sun Jul 13 2008, 06:40PM
Location:
Posts: 70

Are you going to make the spindle or buy one?

Patrick

Tue Jul 13 2010, 11:09PM

Registered Member #2431 Joined: Tue Oct 13 2009, 09:47PM
Location: Chico, CA. USA
Posts: 5639

i have made my own CNC vertical mill too! yours is better than mine. my spindle is a 35,000 rpm DeWalt cut-out mini router, and its no dam good. (1/3 Hp) and louder than hell. It has too much radial run-out. i will switch over to a DC 6000rpm motor.

in my experience the spindle is the most vulnerable part, your set up looks excellent.

i use steppers and Kcam, but your using servos, i like servos much more, post your motor and electrical stuff soon please!

rp181

Tue Jul 13 2010, 11:46PM

Registered Member #1062 Joined: Tue Oct 16 2007, 02:01AM
Location:
Posts: 1529

Awesome. How much is it costing? I find linear slides, shafts, leadscrews, and bearings are very expensive

Dr. H.

Wed Jul 14 2010, 07:59AM

Registered Member #931 Joined: Mon Jul 30 2007, 05:25PM
Location: Bulgaria
Posts: 486

Good day guys

First - thanks for the kind replies

Now on the questions:
About the spindle - we are going to make it ourselves (well ... not me as I am suck with lathes).

Patrick - it looks like an excellent machine - and if it does the job - it is perfect. A piece of advise - it turns out that in 70% of the cases the trouble of milling something comes from the fact that a wrong tool bit is used or the spindle RPMs are wrong.

I am about 60% done with the electronics but will post info soon.

rp181 - the total price of the whole Z-axis is about 150$ (the target price for the whole CNC is under 600$ so I am using as much of scrap parts as possible (but not compromising the accuracy).

Some exact prices - the smaller linear bearings are 10$ a piece, the bigger - 19$ a piece.
The round linear guide - 20mm is 21$ for meter and the 30mm guide is 32$ a meter. I was amazed how expensive the pulleys and belts are. This is why - we are making the other two sets of pulleys ourselves.

As there is interest I've decided to do a more detailed thread, starting with the servos:
They are "Dynamo Sliven" motors - an old Bulgarian firm. The motors were donated to me from a good fellow HAM. Needed new bearings and two magnets needed epoxying (came loose from the housing). The encoders - they are from some kind of assembly line (I took them from the scrapyard for no charge). They are Japanese, industrial grade - so are very robustly build, 500ppr, quadrature. And some pics of the parts.

Cheers

Mads Barnkob

Wed Jul 14 2010, 07:28PM

Registered Member #1403 Joined: Tue Mar 18 2008, 06:05PM
Location: Denmark, Odense C
Posts: 1968

Nice project you got going here, a invaluable tool at a affordable price :D

How big work pieces will it be able to take?

IntraWinding

Wed Jul 14 2010, 08:57PM

Registered Member #2261 Joined: Mon Aug 03 2009, 01:19AM
Location: London, UK
Posts: 581

That looks really good!

I'm going to need a CNC Milling machine before too long, but I doubt it will be anywhere near as good as yours!
Is the only machine tool you're using to build it a lathe?

You say:
'We've made a "tapper" from a piece of the lead screw'.
Is that for cutting a thread in your graphite/teflon nuts?

What will you use to feed back the XYZ position?

Dr. H.

Thu Jul 15 2010, 09:42AM

Registered Member #931 Joined: Mon Jul 30 2007, 05:25PM
Location: Bulgaria
Posts: 486

Good day guys

Mads - the moving table is 600x600mm and the movements of the X and Y are 550x550mm, the Z has 110mm move.

Intra - we are using lathe and manual mill mostly
(well ... a BIG heavy duty guillotine and bender but I pay for using them - pics coming soon to see for what we used them

)

Yep - we used it for making the thread in the nut - here some more pics of the nut and "taper" (P.S. Is it correct to be called taper ??? )

The nuts came out really nice (didn't expect soo smooth movements with absolutelly no play ... for now.

For feedback the motors have encoders - and the pulses from it is fed into the drive electronics (servo motor controller, with STEP and DIR input).

Pics: making the taper, one of the Z axis aluminum plates (phone quality

)

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