sieg x2 or x3?

[Titleiiredneck]

Hey guys, I am looking at starting a prototype for a idea my father and I have had for a while. It wil be out of 60-61 and around 19"x2.5"x2" My startup costs including tooling cant exceed 1k so please help on your opinions. Most tooling "endmills and such" will be free from my uncle as he sold his mill a while back and has some stuff he said he woud give me.

I am looking at a x2 or a x3, but more at the x2 as it can be converted easily to cnc and dro and belt drive in the future but for now I will just need something with repeatability and strong enough to mill 60-61 without taking a year for single pass with a 3/8 endmill. And if this works then i plan to purchace a cnc jr or farm it out so this wont be the mill to end all mills in my shop so to speak. Thanks for your time!

[1andy2]

You'd be hard pressed to buy a mill and covert it to CNC for 1k or less. Plus tooling? Forget it.

I've built CNC mills for woodworking for as little as $700. But that's only because with wood, you can get away with making your own backlash nuts out of acetal for cheap acme leadscrews and still get fairly precise and repeatable results.

For converting a metal mill, I'd think you would want to go with ballscrews/nuts. And those ain't cheap.

Also, you'd want to go with servos instead of steppers. And servos will run you probably 2.5 to 3 times the cost of steppers.

For that matter, I don't really know what kind of torque rating for motors you'll want to go with for milling metal. I went with 425 oz-in rated steppers (milling hard wood like mesquite) they get pretty hot to the touch after about 1.5 hrs of fairly constant use.

Figure on a minimum of $150 per motor. Plus another $100 per motor driver.

So $250 per axis. Plus a good breakout board for another $100. Plus a power supply, call that another $100 bucks.

Then, I dunno, 10 bucks? for a little wall wart power supply for your logic voltage to the breakout board. If you're going to wire in a start/stop relay for the spindle, make sure the wall wart has enough ampacity to handle that coil too. Or get a separate wall wart for it.

Then you need a printer port cable to run from the controller pc to the breakout board. Most of these breakout boards have female DB25 connectors, so you'll need a cable that has MALE DB25 on both ends. NOT DB25 on one end and centronics on the other. The cable will cost you about 7 bucks.

Then you can build a pretty basic controller PC for about $100 or so. Assuming you can scrounge a free case, power supply, and hard drive.

See if you can scrounge a couple of old PC cases for free. One to house your CNC electronics. The other to house your PC.

Hm... some limit switches, an e-stop switch, start-stop relay... call all that another $50.

Then you have your choices in controller software. Mach: good, versatile, costs money. Not too much, tho. Comes with alot of support. Windows only. $100?+

Or EMC2. Free, works just fine. Very customizable. Not as much tech support. Linux only. This is what I use.

When choosing the type of PC to build, newer is not necessarily better. Your primary criteria should be lack of latency. The less latency between all the components of the computer, the more steps your software can generate without risk of LOSING steps. Losing steps is BAD JU JU. Especially if you lose a step that happens to be a motor direction change.

There's a list of low latency motherboard, processor combos on one of the emc2 pages. I'd go with one of those regardless of whether I went with EMC2 or Mach for the controller software.

Then you're going to have to price what some quality ball screws cost. And here I cannot help you, other than to say you'll probably spend a couple hundred bucks per axis.

Then you've got various bearings, motor couplers (get zero-backlash couplings), shaft collars to capture the bearings, etc...

The various motor housing brackets and bearing housings you should be able to make yourself manually with the mill itself, tho.

Sorry I can't be more specific on the mechanics side of things.

eta: couple of other things I thought of. Some ferrite chokes for EMI reduction. Wrap your motor wires through these a few times. EMI can cause lost signals to the motors. Or even FALSE signals. This is bad ju ju. Maybe not necessary if your motor wires are less than 6' long, but it's cheap insurance.

4+ pin connectors for your motor to break out board connections. both male and female. Basically you'll wire up the female connectors to the various numbered pins (which have screw-down posts) on the breakout board. Secure those female connectors to the rear of the PC case all your CNC electronics are mounted in. Then wire all your motors to the male connectors. This way, you can simply unplug or plug in those wires and won't have to resolder stuff if you want to move your machine.

[Titleiiredneck]

1andy2, yeah i figured the cnc conversion kit would be around or over 500-600. I really just am lookin at the mill and tooling for under 1k, also looking more at the x2 "for future conversion to belt drive and DRO and possibly cnc but doubt the cnc part" I will absoultly need DRO in the future and was looking at the grizzly GO704 model but cant figure out if the dro on it is for all 3 axis.

[JFettig]

First off, your asking for something for nothing.

Secondly, I would highly recommend you find a little more money to invest in the X3. I have both. The X2 now is a cnc. I spent a considerable amount of money with large motors, quality drives, ballscrews on all axes and it now sits in the corner of my garage and the controls box somewhere in my house and the pc that drove it in another room. I haven't hooked it up in a couple years because the X3 is way more useful for most things. It is considerably better.


Jon

[1andy2]

Why don't you skip the conversion kits for an x2, get the x3 instead, and design all the parts to convert it yourself?

Good CAD design practice, anyways.

Nice thread. I've been considering doing a CNC metal mill, too.

[Titleiiredneck]

Yeah the more i read on the x2 its seems i would be better off with a x3 or larger mill. My main idea was to get the prototype off the ground and then invest in a smaller cnc mill simmilar to this http://www.cncmasters.com/index.php?...table-top-mill


For around or under 6 k wouldnt mind investing since i would use it for other things around the farm anyhow. But as of now this is a pipe dream until if/when i get the item on the market. This is why i was looking into the x2, for LOW COST but i need reliability and repeatability and those are 2 diffrent things with this machine from what i read. I just need to find a deal on the x3, mabye harbor freight will come out with another 20% coupon soon and that will drop the cost a few hundred.

My main concern is converting to DRO after purchasing, not cnc since i would upgrade to a larger cnc mill or farm it out if the prototype took off.