[oxford]

Hello all. I have been perusing the forum for information on small cnc mills.

It seems like converting a Sieg Super x3 manual mill to cnc would be most economical for the size mill I need.

How strait forward is the process?

What parts will I need?

How long does it take?

Are there affordable true servo drives out there? I have read that some drivers or controllers (is there a difference between a driver and a controller?) used for servo motors are really just for steppers and can't run the servo at higher speeds.

Next, are Nema-34 motors a size? I ask because I have seen Nema-34's with all different kinds torque.

Stay tuned for more questions... I have yet to know how little I know :P

Thanks for the help guys

[oxford]

Motors to be on the lookout for:

AC, DC, brushless?

RPM range?

Any thoughts there?

[tauntdesigns]

I was going to build my X3 cnc conversion, but then changed my mind and bought the CNCFusion X3 deluxe kit. I was going to have to buy some manual tooling that once I cnc'd my machine I'd never use again..... so I just bought the kit.

Do you have a lathe to turn down the new screws with?

If you go the route of building everything, you'll need:
Ballscrews, ballnuts, bearings, stock to make bearing blocks, motor mounts, nut blocks, couplers....................
If going with stepper motors you can use direct drive couplings.
If going with servos you'll connect the screws to the motors with teeth pulley and belts.

Nema34 is a standard mounting configuration (bolt holes and mounting surfaces) and they come in different torque.

I'm using my cnc x3 to build a cnc lathe at present.

I bought the cncfusion kit and built my electronic control box (electronic scare me)

I'm kinda new, but have done a couple of projects from the knowledge here on the ZONE.

Happy machining,
Jack

[neilw20]

I have a factory SX3 that runs steppers.
On a machine this size they are MORE THAN ADEQUATE.
I have reduced the maximum feed rates from 100 IPM on X and Y and 75 on Z to about 60% of that because doing fine intricate work, and a lot of it in a semi-manual mode, the speeds are more than the brain and hands can handle without crashing into things on rapid. If you want to run it fully fast and automatically it will do it. Servo motors would be a complex, expensive overkill. Most small work is done at low feed rates, because you can't push small cutters too fast. THEY BEND even when you don't push them. Repeatability better than 0.001" all axis with a bit of care. I am 100% happy with my 4 axis lot. The only time you would need really fast rapids, is drilling zillions of holes, and without a tool changer, you would not want to do too many.

Cheers.

[oxford]

Thanks for the replies.

I was looking to make something that could mill a contoured surface quickly.
I will be milling small blocks of acrylic into surfaces with parabolic cross-sections.
....(Think of the reflective part of a flash light fabricated in four parts from four separate pieces)

Will high speed milling still be a problem?

All said and done, I would prefer to put a mill together that is hard to outgrow

(neilw20 is that a software fix you use to slow down the steppers?)

Thanks again guys

[neilw20]

Slow down is just in the steppers.
Any cutter below about 1/4" will flex noticeably under load. You can have speed, but accuracy must suffer unless you are using a huge stiff cutter. If it is large surface then a big cutter will do. As for the power at high speed, the steppers can still overload the 1KW spindle, so don't waste time on a servo system on this machine. If you increase the HP then the tower stiffness will become significant. I have modded mine and get 360mm Z travel. 380 is practical if the head is rotated (a great feature not to be over looked). It is then a lathe with adjustable tool height.

Cheers.

[oxford]

Thanks again neilw20.

Are you running a closed loop drive?

Also, are drives and controllers the same thing?

[oxford]

Is it possible to just couple on some steppers without changing any of the drive screws?

No big changes, just throw on some strong motors... Could it work?

[cadmonkey]

Is it possible to just couple on some steppers without changing any of the drive screws?

No big changes, just throw on some strong motors... Could it work?

Sure it's possible but check the backlash you get on the screws as is. Even adjusting the b/l on my X3 screws I couldn't get better than ±.008 and the handle was a @#&$ to turn. Once you've gone to the trouble of buying motors, drivers, power supply, pc controller and everything else, what's a few screws? Even if they are low grade, they're probably going to leave you happier and you'll have bought smaller motors, smaller power supply, etc.

[oxford]

...Ok, so if I am going to go through the trouble to retrofit, might as well upgrade the ballscrews too.

What size ballscrews are good?

Along that thread, what torque motor is best.

I would like high travel speed (I'll be using a larger end mill)

I was looking at 1200 oz-in.

I have a Tim Allen approach: "more power" . I read though that if power/machine size is missmatched, I will create my own set of problems such as choppy finishes.

As always, thanks for the feedback.

[automationtechinc]

check this package.
http://kelinginc.net/ControlSystem.html
http://kelinginc.net/Three34XCNCPackage.html

[oxford]

Sigh....Now I just need to get my wife's ok.

This could be a real stretch, but how do you guys deal with explaining the budget to the wife?

[MRM RCModels]

It's easier to ask forgiveness than permission

[neilw20]

It's not your fault but you can take the blame.

[oxford]

Tempting....

Does doing the dishes first help prepare for the confession?

I've been married ten months now and am still wary/a novice of pushing the envelope:P

[neilw20]

I've been married 35 years now. The first 17 were the hardest.

Now I just take the blame and run with it....

[oxford]

Were those tough first 17 years the years you were setting up shop?

[neilw20]

Training wheels .. :argue:

[MRM RCModels]

I told my wife either I can stay home and work on projects all night or go out to bars around pretty girls all night. Either way I will put the energy in someone or somewhere.

Haven't had much of a problem since

[rowbare]

Sigh....Now I just need to get my wife's ok.

This could be a real stretch, but how do you guys deal with explaining the budget to the wife?

Stand in the shoe closet while you explain it to her...