Motors?? Motors??

[Imacman]

Quick question... can't seem to get a consistant answer. What size motors (oz) for my build... It has ACME 1/2' Screws 12 TPI all a round... they measure X=36" y= 19" Z= 9" I'm using decent thompson enclosed linear bearings on solid rods 1/2".... it is being made of doubled up Heavy MDF, some 1/2" Acrylic, Some aluminum, and several (6) pipe rails with internal threaded rod for bracing... the final structure should prove to be Very ridgid. So...I want the optimum motors/ Board and controller and power supply for such a set up...without overkill... I will be using the CNC on wood, aluminum, and HDPE plastic, acrylic etc.

MY QUESTION: Could someone please tell me what to buy... I am literally burned out from looking through forums & websites...I'm new to this... and I just really need someone to tell me what will be best,, not looking for the cheapest...or even best bang...looking for the Ideal setup. The sort of "In a perfect world...you should definately get... "

Thanks In advance

[2ferrous]

I suggest 1200oz/in steppers coupled directly to the screws with Gecko 203V's to drive them. That would give you 100ipm rapids and plenty of power to do aluminum work. Servo's might be faster but the extra set up time might not be worth it.

Timothy

[mactec54]

Hi Imacman

The best choice for motors drives package, you could use the same as Rod has
very easy to set up, his post is here

http://www.cnczone.com/forums/showth...=102439&page=9

You can look at the DMM Technology to get them
They are in Canada

http://www.dmm-tech.com/

The 400watt motors will do you just fine

Everybody says servos are hard to set up,Some may be but not these, they are easier than steppers to get going without the wine, From out of the box settings Rod is using his, with no tuning of the drive, Just tuning in Mach His machine is good for more than 400IPM & very smooth, watch all his Videos Here is one

YouTube- cncvids 028.AVI

[ger21]

Do you have any pics of your machine? That would help.

How fast do you want to cut and rapid at? More than likely, your 12tpi screws are a terrible choice. With 1/25" screws, 2-4 turns per inch is ideal, depending on speed required.

Imo, servos would be overkill, and cost twice as much as a good stepper system.

I'd look at a G540 with 380oz steppers from Keling. If you keep those screws, you can go with even smaller motors. Smaller motors will give more rpm's than larger motors, and 270oz might be a better choice.

Ideally, the steppers, drives, power supply and screws all need to work together as a matched set. Because of this, it's difficult to give info on what the best motors are.

[mactec54]

ger21

I agree the screw choice is not the best, but if that is what he has then he will have to work with them

The servos are a better choice than your steppers, & the cost is about the same the servos from Dmm come with everything ready to run, you get a Estop breakout board drives, motors, encoders, wiring & home/limit switches, & great support

[ger21]

Originally Posted by mactec54 The servos are a better choice than your steppers, & the cost is about the same the servos from Dmm come with everything ready to run, you get a Estop breakout board drives, motors, encoders, wiring & home/limit switches, & great support

Their website isn't the best, but it looks like minimum $1000 for a package?

A G540 is $249, and has a breakout board built in, and 4 motors are $160 ($39 each). Add $60 for a power supply, and your at $470. You can get limit switches for $2 each. So, about half the price.

Not saying the servos aren't "better", but they're much more expensive. But I'll seriously consider them for my next machine.

[Crevice Reamer]

Twelve TPI is going to slow your rapids a bit. You will need fast motors & drives to achieve good speeds.

This is what I recommend:

http://crevicereamer.com/Page__57.html

CR.

[Imacman]

Originally Posted by ger21 Do you have any pics of your machine? That would help. How fast do you want to cut and rapid at? More than likely, your 12tpi screws are a terrible choice. With 1/25" screws, 2-4 turns per inch is ideal, depending on speed required. Imo, servos would be overkill, and cost twice as much as a good stepper system. I'd look at a G540 with 380oz steppers from Keling. If you keep those screws, you can go with even smaller motors. Smaller motors will give more rpm's than larger motors, and 270oz might be a better choice. Ideally, the steppers, drives, power supply and screws all need to work together as a matched set. Because of this, it's difficult to give info on what the best motors are.

Hi Guys, thanks for the information, as you can imagine... my build has changed as it is progressing... I got a great email from Ahren, and based on my modifications to the design..... Ahrens reccommendations are pretty much what is above.

My design is now fully supported 20mm rails X= 1000mm Y = 700mm Z= 300mm actual travel is a few inches less than this area, I have switched to a 5/8" *tpi acme screw which I intend on upgrading to ball screws after I get a bit of experience under my belt. I am using 1/4 to 1/4 Helical style direct couplers. I have read really good things about the Gecko 540 drive so I'm excited about that. Thanks for the Info and advise.

I'm in the process of building a workshop out back, so I'm at a bit of a stand still build wise until it's done in a about 2 weeks. I'll be publishing a live website when I start the build assembly, I'll be looking for lots of advise, as as i will be assembling it "Live On line"..ie Live interactive audio / video chat on the website from the workshop so people can give me advise live on the spot, and see what I'm doing... it should be very interesting!.

Paul

Newfoundland

[ger21]

Originally Posted by Imacman I have switched to a 5/8" *tpi acme screw which I intend on upgrading to ball screws after I get a bit of experience under my belt.

Like I said before, everything needs to be a matched set. What works best for your acme screws may not be what works best for the ballcrews.

[mactec54]

Imacman

If you have not turned down the 5/8 acme, go as big as you can for your coupling mount
on your screws, 1/2" or 3/8, 1/4 is to small for those 5/8 screws

[Imacman]

Thanks for that Mactec.... I have not turned them down yet.... but was going to turn them to 1/4" ( I got the helical couplers very cheap, so no big deal) so they logical coupler choice would be Lovejoys then?... I can get them from 1/4" on the motor side to 5/8 " on the screw side?... would this be correct?

I had considered making some "helical type" up from aluminum rod with my drill press and band saw... seems like a pretty straight forward part to make....unless I'm missing something in the engineering of them?

Thanks

Imacman ( Paul )

Newfoundland

[2ferrous]

Yea, 1200oz/in might be a bit overkill.

Maybe if I had a coffee that morning I would have seen your post said 1/2" ACME screws, not 1"....

Glad to see you going with a Gecko G540. They work well, I'm sure you'll be happy with it.

Timothy