[bkboggy]

Trying to pick a setup for Joe's '06, and not sure what to go with... so far:


Probotix:

Not sure if I should choose PBX-2 or PBX-RF breakout board.
http://www.probotix.com/3_axis_stepp...or_driver_kit/


Keling:

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


HobbyCNC:

http://www.hobbycnc.com/products/hob...oard-packages/


All priced fairly close. What do you guys think? I would go with Geico 540 and then buy the rest, but it would come out much more expensive and those 3 above are good enough for this machine.

[Crevice Reamer]

First of all, doesn't this router require FOUR stepper motors and FOUR drivers? That makes the G540 a lot more cost competitive. You can't compare prices on a 3 axis system if you need 4 axis.

Secondly, You have a lot of area to travel. You will need all the rapid speed you can get, and just will not be happy with poor performance.

Thirdly, the MOST expensive thing you can do, is to buy something cheap now, and then have to fork out more dough to replace it later.

Get the powerful and reliable G540. Run it with a 48V PSU.

CR.

[bitbanger]

If you want your crevice reamed, follow crevice reamers advise. Otherwise, we have had many Joe's builders have good luck with any of our kits.

I personally prefer the ProboStep kits because they can handle 40+ volts - which translates to really fast rapids.



>Len

[LaserImage]

If you want your crevice reamed, follow crevice reamers advise. Otherwise, we have had many Joe's builders have good luck with any of our kits.

I personally prefer the ProboStep kits because they can handle 40+ volts - which translates to really fast rapids.



>Len

That's a pretty ****ty thing to say! If you have something against the G540 then say what it is, don't slam CR for his opinion.

[bkboggy]

CR - Completely untrue. You're thinking of Hybrid. This is '06--it requires only 3 motors and only 3 drivers. I have seen a lot of people being happy with the above setups I've mentioned. Have to remember that this build is 90% MDF, I do not need anything super fast.... however, I do want something reliable.

That Geico 540.... what is included inside of it? 4 drivers and 1 control board? So I would only need to get a power supply and 4 motors? I'm unsure.

[LaserImage]

That Geico 540.... what is included inside of it? 4 drivers and 1 control board? So I would only need to get a power supply and 4 motors? I'm unsure.

1 - Gecko G540
+
3 or 4 - steppers
+
1 - Power supply

= all you need

It will take you about 20-30 minutes to solder your motor wires to the db9 connectors, download the xml file and make the changes to your parallel port. It really doesn't get much easier than this. If the G540 is appropriate for your motors then you won't beat this combo. If you calculate out the individual costs, the G540 is much less expensive than other solutions and the time savings of having it all integerated really pushes it over the top.

Gary

[Crevice Reamer]

My mistake on the number of motors. The G540 is MUCH more than drivers and breakout board. Along with all of the unkillable features of the G203V, it also includes mid band resonance dampening, 10 microstep and microstep to full step speed morphing. NOTHING else comes close to this value. It even comes with the motor connectors, so all you need is some wire:

http://cgi.ebay.com/Servo-Motor-Wire...3286.m20.l1116

a straight thru DB25 cable, some 1/4 Watt current-limiting resistors available here:

http://www.digikey.com/

and your motors and 48V power supply.

CR.

[bkboggy]

Woo.... does sound good. Everyone seems to praise these geico drives. Maybe I should go with it if I decide to upgrade.

So, what kind of motors do you guys recommend? And what kind of power supply, of course?


For enclosure I'm thinking of just using a mid-tower from a salvaged PC. Mount 2-3 120mm fans and it should stay cool. Think I should use a separate power supply for these fans or will I be able to feed them off the main one?

I'm also thinking of adding some fans behind each motor to keep them cool. What do you guys think? Has anyone done something like this before? Is it worth it?

[LaserImage]

bkboggy

The motors you need really depend on your specific application. I'm not really knowledgable about which work best for which, but someone here could help you there. As for the enclosure - I have a single 90mm fan in mine and it works just fine, no overheating problems at all. If I remember correctly, the G540 doesn't even need cooling until your ambient temp reaches about 100F. The motors won't need cooling either, I have seen posts from Keling that they are good at anything below 90c - that's freakin hot! The power supply really depends on the motors and how hard you need to push them. I have 3 keling 286oz steppers driven with a 24v psu and I get 130ipm on my 18" x 36" machine. I could use a 48v psu and get more speed/torque, but I don't need it.

Base your motors on your speed/torque, buy a drive that will allow the voltage/current that you need and then a power supply with the voltage/current that will do the job. The hardest part for me would be figuring out the "best" motor for the job, the rest is simple math.

Gary

P.S. Geico = insurance, Gecko = drives

[bkboggy]

Gary - I don't even know any companies to ge the power supplies from... same goes for the motors. The machine cutting area is going to be about 24x48. Motors will have to move MDF, HDPE and 2.25HP Hitachi Router.

[LaserImage]

Gary - I don't even know any companies to ge the power supplies from... same goes for the motors. The machine cutting area is going to be about 24x48. Motors will have to move MDF, HDPE and 2.25HP Hitachi Router.

You can't beat Keling for the motors and power supplies, they might be able to tell you what motors would be best for your setup. I honestly don't have enough experience to tell you what motor size/specs are best for you, but I do have enough experience to tell you that Gecko drives and Keling motors are a great combination!

Gary

Keling - http://www.kelinginc.net/ (also sells a lot on ebay)

[bkboggy]

Thanks. I've contacted them to see what they will recommend. Unless someone will recommend something else, I will go with them.

What about these motors:

http://www.homeshopcnc.com/RSstepperMotors2.html


I hear a lot of people talking about NEMA, what do you think:

http://stepper3.com/shop/index.php

[Crevice Reamer]

NEMA is not a motor name. It is a stepper motor size standard set by the National Electrical Manufacturers Association. We generally use Nema 23 and Nema 34 size motors.

CR.

[Crevice Reamer]

Let's talk stepper motors. The Torque rating is what you get with the motor at rest. Torque falls off with increase in RPMs. To do any WORK with it, you need to carry much of that torque up to higher RPMs.

It is important to match the motor to the load. You can't just assume that bigger is better. Bigger motors run somewhat slower than smaller motors. A router, more so than a mill, needs high rapid speeds. You will get best performance by wiring the motors in Bipolar Parallel.

The way to get best rapid speeds is to be able to get torque at high RPMs. This is accomplished by matching the motor's best voltage to the power supply voltage. Higher voltage pulses charge the coils more quickly and maintain torque to faster speeds.

Using the G540 as the controller, (and you should, it's the most bang for the buck) You can operate with a max voltage of 50V. Formula for best voltage of a stepper motor is 32 times the square root of the inductance. With the G540, you will want motors with best Voltage between 50 and 65V.

The Keling 60V KL23H276-28-4B with the KL 48V 7.3A PSU, may be all the motor you need, depending on how you drive your axes.

http://kelinginc.net/KL23H276-28-4B.p

CR.

[bkboggy]

CR - How do I wire motors in Bipolar Parallel? I contacted Keling and they've recommended KL23H2100-30-4B ( 3/8” Dual shaft with a flat) 382 oz-in motor and KL-600-48 48V/7.3A 115V /230V power supply.


Where did you see the voltage for the motors? When I clicked specifications all I saw was 3.2V rated voltage for yours and 3.6V for the one they recommended.

Also, you're saying to match my motor's voltage to my power supply's. So wouldn't I need a 60V power supply for that motor you've mentioned? A bit confused on that part.

[Crevice Reamer]

Keling is the most bang for a buck in a stepper motor, but frankly, he recommends what he has in stock to sell at the moment--Not necessarily what is best to use. The 75V 382 is not as good a match for the G540 as the 65V (out of stock right now) 387. And the 3/8 inch shaft requires boring out 1/4 inch shaft connectors.

Stepper motor best voltage formula: 32 times the square rood of inductance in mH. Easy with a calculator.

There are not currently any stepper motors that perfectly match the G540s 3.5A and 50 V requirements--although the 60V 270 comes closer than most. Try to get a motor with voltage as close to 50V as you can for best performance.

You can only use 50V max PSU with the G540.

CR.

[LaserImage]

they've recommended KL23H2100-30-4B ( 3/8” Dual shaft with a flat) 382 oz-in motor and KL-600-48 48V/7.3A 115V /230V power supply.

Those motors calculate out to a 75V power supply, the G540 is 50V max. 50V would probably run just fine, but know that you won't get the best performance possible. The 23H276 motors are probably the best match for the G540 with a max voltage of 47.46V. The way to calculate the voltage is:
32 times the square root of the inductance per phase, expressed in mH. ie. the 276 is 2.2mH so - 32*1.48323... - 47.46...

Gary

[Al_The_Man]

I hear a lot of people talking about NEMA, what do you think:

NEMA rating is a mounting frame size for motors in general, it is not an indication of the torque etc, as you can get various stack lengths for steppers and body length for servo's for each NEMA rating, this will influence the torque output available.
Al.

[Crevice Reamer]

The 23H276 motors are probably the best match for the G540 with a max voltage of 47.46V.Gary

I think you mean the 282 ouncer. This would NOT be a good match for the G540, which can only output 3.5 amps, because THAT motor requires 4.2A.

Under amping a motor reduces its torque. So The 282 would effectively become only a 243 ounce motor with the G540.

CR.

[LaserImage]

I think you mean the 282 ouncer. This would NOT be a good match for the G540, which can only output 3.5 amps, because THAT motor requires 4.2A.

Under amping a motor reduces its torque. So The 282 would effectively become only a 243 ounce motor with the G540.

CR.

The very best would be a motor with 3.5 amps and 2.44mH inductance. I don't know if the "perfect" motor is out there. I am using the 282 oz motors and they work fine for me, even at a "real" 243 oz. If someone would come out with a 3.5A, 2.44mH motor, I could see them selling a ton of kits - 3 or 4 of them with a G540 and a 48V, 7A PSU - what a combo!

Gary