Newbie- Decisions, Decisions...

[WannaBe3D]

Ok, to say that I'm a newb is an understatement...I think. I've been doing research for about the last 3-4 weeks and have more questions than I started out with...

I want to build a CNC machine, but I'm not sure if 3-axis can accomplish what I need to do.

Reason: I need to build my CNC to be able to make R/C helicopter parts. Most of these parts will be made of aluminum, some of plastic (Delrin). Most parts will be symetrical, but I want the ability to do asymetrical parts as well.

These parts will be fairly small (800mm X 800mm X 400mm max), but fairly complex.



What I want to build is simular to this picture, but with 7 "spindles." I know the design above isn't all one piece, but I need to be able to produce all of the parts needed to complete a design like this.

Also, you can't see it in the picture, but on the bottom of this piece there is a "mount" that sits on the end of a 12mm shaft.

Budget: I have set a budget of $1,500 USD.

Complications: I'm having a hard time determining a layout to accomplish what I need. I'm also not sure how many axis I need to accomplish my goals.

Any advice?

[rbcmetalwork]

"These parts will be fairly small (800mm X 800mm X 400mm max), but fairly complex."

Was this a typographical error? Perhaps 80mm x 80mm x 40mm?

[WannaBe3D]

Nope, I meant 800 x 800 x 400...(relatively small)

[dertsap]

that's a 4 axis job if you plan to machine it complete , or easily a 3 axis with some fixturing that you can manually rotate the part at an M0
if you fixtured right and do some funky toolpathing then you can complete it in two ops with either 3 or 4 axis . it all depends upon how creative you are

[WannaBe3D]

Originally Posted by dertsap or easily a 3 axis with some fixturing that you can manually rotate the part at an M0

What does theat mean?

On a 3-axis, I can cut the top side, turn it upside down, and cut the bottom side right?

[Drools]

800mm = ~31"
That is small?

[WannaBe3D]

Ok, forget that I even said "fairly small"

[Drools]

just a question off topic, what scale of copters are you working on?
Just for comparision my 3 axis 8020 based gantry style machine based upon mostly cncrouterparts.com parts cost me about 2000.00. The size is X30, Y20, Z5.
Is it possible to build a 3 axis @ 35,35,5 for 1500.00?, maybe if you can get some deals.

[dertsap]

Originally Posted by WannaBe3D On a 3-axis, I can cut the top side, turn it upside down, and cut the bottom side right?

there's more to machining that particular part than just that
yes you can machine both sides of the part to get the main body but you still need to machine the pins or the holes for the pins , and you'll need to rotate the part to 5 different points

[tskguy]

Dude I have flown RC helis for close to ten years. What kind of RC heli is going to need a 31" rotor hub??? It seems a little big to me. Shoot my 90 sized heli only swings 710mm long blades.

And have fun balancing a 7 blade head!!

[WannaBe3D]

Originally Posted by tskguy Dude I have flown RC helis for close to ten years. What kind of RC heli is going to need a 31" rotor hub??? It seems a little big to me. Shoot my 90 sized heli only swings 710mm long blades. And have fun balancing a 7 blade head!!

Obviously I'm not going to machine a 31" hub. The hub itself is only about 60mm in diameter.

I want to machine larger parts than the hubs, but the hub it the most complicated piece so I'm trying to see if I can get a mill to make it. That is unless you know someone who makes a 7 spindle hub with grip extensions...

[15mgtar]

you can not build a precision cnc machine that will be able to do those jobs at $1,500 USD.