Another X2 CNC Conversion (yay!)

[skmetal7]

Ever since I got my x2 mini mill I have wanted to CNC it. But not until Hoss came around did I know how to make the z axis (thanks Hoss!!!!). I'm sure if I put some thought into it I would have designed something like what he has, but im lazy. I didnt like the other disigns out there that lifts the z on the side where the gib is (I can just see the head twisting and creatign more friction). Sooooo i copied his design for the z axis. I came up with my own design for the x and part of the y(but the y is sort of like Hoss's).

It will retain some manual function, with small cranks on the ends of the steppers. Mainly for positioning.

I plan on using A/C bearings for the x and y from VXBbearings, and ballscrews/nuts from homeshopcnc.com, steppers from them as well, and gecko drives.

BTW does anyone have dimensions for the ballnuts and steppers? I used rough dims. for the CAD modeling, but I'm sure its not correct.

Not sure what CAM program to use (they are all so expensive). I like ONEcnc but its way out of my budget.

Pics 1 + 2 are the CAD renderings
Pics 3,4 + 5 are the ballnut mounts being made (3 is .040" DOC @ ~15 ipm 3/4" endmill)
pic 6 is the almost finished mount (i still need a tap)

[hoss2006]

Hey skmetal7,
Nice CAD drawings!
What program do you use?
For CAM, try CamBam. It's Free and they have some nice tutorials to get you going.
http://www.brusselsprout.org/CAMBAM/
It's still beta but most everything works.
Hoss

[cncJerry]

Are you sure you want to use direct drive instead of timing gears and belts? Also, do yourself a favor and look at servo motors for a mill this size. I have both, steppers and servos, and after fitting the servos on my new mill, I don't know why I lived with steppers. Unless you are running them closed-loop which adds to the cost, they are very frustrating with missing steps. Servos on the other hand, at least fault when they get ahead or behind so you know there was a problem.

I was very pleased with the service and support from Keling, Inc. They had the best prices for Geckos, have decent power supplies and a good selection of steppers, though Dan Mauch (camtronics) seems to have better prices on larger servo motors. I used his 1100 oz/in servos for my R45 clone.

You can get the stepper mounting dimensions from just about anywhere. I assume you are using NEMA 34 size or at least you should. Just google NEMA 34. NEMA 23's are just too small for a mill like the X2 or X3 so look for NEMA 34 mounts. Also, if you do go stepper (take my advice and go servo) and use NEMA34's, you can always get NEMA 34 servos when you get frustrated with losing steps and not knowing until you measure the part.

So check Keling, Inc for the size motor you want and can afford in oz/in's. I don't think you would want anything under 500 oz/in and make sure they are bipolar. Bipolar steppers in that range are generally NEMA 34.

Check them out:

http://www.kelinginc.net/SMotorstock.html

I saw some NEMA 34's in the 640 oz/in range for $89. If you buy from them, they give a discount on the geckos. I really think you should go larger, though but once you get up around 800 oz/in, servos are very competitive.

Don't try to save money on drivers. I think the world of Marris at Gecko. They have a very interesting warranty. If it fails for any reason, the first time they will fix or replace, even if you hook the power up wrong. Can't beat that.

Mach3 is great software and Art, the author, is a really great guy. There is a very active group on yahoo. I've used his software for years.

Anyway, I hope this helps. I don't have a vested interest in any of these companies but have been in the roll-your-own CNC for about 12 yrs and over 30 yrs in CAD/CAM/CAE.

regards,

Jerry

[skmetal7]

i think im going to use the 260 oz/in model from homeshopcnc.com. i think a nema 34 would be wayyyyyy overkill for a mill this size. and the more oz/in, the slower the rpm will be and therefor the rapids. i havent really looked into servos but they are kinda pricey and i would still have to buy encoders. i would like to use them, maybe i will think aobut it.

oh and im using pro/engineer student version for CAD

[cncJerry]

isn't an X2 a Seig X2? Like the X3? Maybe I'm missing something? Or is it like the mini-mill?

[hoss2006]

The X2 is the Seig X2 mini-mill, It is half the size and cost of the Seig X3 and a little bigger than the Seig X1 micro-mill.
Not too big and not too small, just right. But I might be Biased.
Hoss

[skmetal7]

Hoss, i tried using the CamBam software but it wont let me import .iges files. it lets me import .dxf files from autocad but i dont use autocad.

[skmetal7]

Got some stuff done this past week. I made an x axis stepper mount, made a spacer block for the y axis, and made a support for the z axis column.

The first few pictures is me making the x axis stepper plate. im gonna have to mill slots in the holes that mount to the x axis, because i didnt know the leadscrew is not centered with the table

next pics is the y axis stepper block made from mystery aluminum from school, lol. its thicker than i designed for, but thats good since it will give me more travel on the y axis. a plate for the stepper standoffs and a/c bearing holder will bolt onto that.

last pics is the support being made. this decreases the deflection in the z axis. befor i had ~15-20 thousandths of deflection and now its around 3 thou.!!!! dont look at the welds they are bad, haha; but strong so i dont care!

[hoss2006]

Good idea on the column support, now you got me needing to check mine for deflection. Especially with the added weight of my accessories.
Thanks Hoss

[skmetal7]

someone posted a link to a Japanese site a while back. thats where i got the idea from. the site is gone now but luckily i saved some of the pics, and drew some plans from that.

[whoafat]

SKMetal,
Newbie here has admired Hoss's design and intends to use that as the basis for my own design. However, I am also interested in a left-handed X-axis power transmission sheme, such as yours. If it is not too much of a bother, could you share the dimensions or drawings for the x-axis. Hoss's clever approach has actually gained some additional x and y axes range. Do you anticipate getting extra travel on the x-axis? I do not know if there will be frequent needs to unsaddle the platform. With Hoss's design, I don't know if the motor will have to be removed, assuming enough slack on the electrical cable. Just something to think about. Please not that I'm posing the above remarks to pick your brains and not as a criticism,
thanks for your understanding,
Wilfred

[skmetal7]

i wont post any dimentions until i know everything fits and works properly. i dont want to hand out dimentions that arent right, lol.

the x axis travel is the same as stock travel. the table will not come off the dovetails (it cant). and the y axis is going to be like what hoss' has for travel