Xylotex Vs Gecko Pros and Cons

[Alex_Cole]

I am going to be replacing the electronics on my desktop cnc. I have been doing a bunch of resarch on Xylotex and Gecko systems but I am pretty green about all this stuff. Can you guys help me understand the difference between these units and what would possibly justify on over the other.

I like the Xylotex system so far...it seems well supported and simple in design but yet there must be a reason people use Gecko 201 drives instead of the Xylotex but they seem pretty compareable to me except for price...so what gives?



Here are details about my machine.

Dyna Mite 2400 mill
2.5mm pitch lead screws
Home switches on XYZ

Motor Details. The motors on the machine are 8 wire
Series 1.21ohms 1.8 amps
parallel .31 ohms 3.6 amps

The sticker says 27 Oz/In.

Now the motors that are on the machine now were working...just the old controller went out.. THe motors are geared to the lead screw with about a 6 or 10 to one ratio

The lead screw is 2.5mm pitch which should be about .0984" per rev

The origional system was able to run the machine with these motors at a max rapid of 30 IPM.

I am looking to run the system either with these motors if possible or replace them if absolutly necessary. If I do replace them I would like to get the speeds up to more like 50 cut 70 rapid.

So let me have it. Would the Xylotex work ok with what I want to do or do I need somthing more like the Gecko to do this.

Any feedback is greatly appreciated.

Thanks

AC

[joecnc2006]

The Gecko's are rated at a much higher voltage and amps, will drive large motors as well as smaller ones.

for the amps of your motors, i can not see them only being 27 oz/in is it possible they are 270 oz/in?

what is your power supply?

for the smaller motors i would think the Xylotex will work fine for you.
Also what is the controller software you are using? (parallel or serial interface).
And are you going to use a breakout board?

[Alex_Cole]

The stickers definitaly say 27 and not 270. Another note about the motors I failed to mention is they are 100 steps per rev and not the 200 that most people here use.

The control cabnet has a 5v power supply and a 24v 4.5amp power supply. I have removed the 24v supply currently as it was used to power the old controller system and the 5 volt is still there for switching the spindle board.


I have been looking at the 4 axis system kit from Xylotex with the 269oz/in motors and power supply...ect. I can get this system with motors for the price that I can get the geckos by themselves. This would allow me to have replacement motors if I needed them. I am just not sure if they would be strong enough to move the machine with a direct couple to the lead screw(might need 456oz/in ones) sence the motors that are on there now are geared down. The lead screw has a pitch of 2.5mm or .098 per rev.

Are the Gecko drives faster(steps they can output) then the xylotex? What would be the limiting factor in the speed that these two systems would have?

I know very little about any of the technical side of the driver systems.

If i get the system with new stepper motors I would like to get rapids at 70ipm, and using my existing screws(not an option to replace right now) with a new direct couple motor(no gear reduction) That equates to roughly 714.28rpm. is this going to be possible with the xylotex board? I believe that these smaller stepper systems usually max out at about 500 rpm. Would the gecko be able to step the system faster or are they the same?

I think the xylotex will work but I have a 10,000 rpm spindle and I just don't want to end up moving at like 5 ipm when I will mostly be cutting aluminum. It will eat my cutters I would like to cut around 40-50 consistantly.

THe work envelope of this machine is small 6"x 5"y 4"z but very rigid and smooth. The machine weighs about 250lbs total.

Thanks again for helping the clueless one!


AC

[joecnc2006]

Can you post pictures of the machine, motors, driver, leadscrews and such, from what you describe it is a very small micro mill, in which the xylotex will prob. work just fine, I run 80ipm with my machine, (joe's CNC Model 2006) using the hobbycnc kit. no matter what system you get your limiting factor will be your leadscrews TPI.

joe

[Alex_Cole]

I will try to take some pictures this in the next day or two and post them for you guys. I will show you the gear reduction and the whole layout of the machine.

Thanks

Ac

[ger21]

Speed is related to voltage. Double the voltage, and you double the top speed. YOU ususally want to use a voltage that is 10-20x the motors rated voltage. The Xylotex is limited to 24V-30V, while the Gecko's are limited to 80V. But that's not the whole story. Generally, higher current motors have lower voltage ratings. By using Gecko's, you can get motors with higher current and lower voltage ratings, and get even more top speed.

[Torchhead]

Wow. Over 3A and only 27 Oz-in? Those are either the most inefficient motors around or there is a zero missing. At only 3A you can get a 496 oz-in motor (see them at www.homeshopcnc.com) or a very cost effective 300 oz -in both of which will work with the Xylotex. You should be able to direct connect either of those motors and with a 2.5mm pitch screw I would think 50 IPM would be doable with a 24VDC power supply. With Geckos you could get more RPM by using something like 48VDC. I think with a 6" travel that being able to move 100 IPM for double the money might not make economic sense.

We sell products that use both drives (Xylotex and Gecko) but for different applications.

Tom Caudle
www.CandCNC.Com

[wildcat]

ger21 - Forgive this naive question but you are saying that a motor rated for 2V should be driven with 20-40V? I am confused... if the motor is rated for 2V what allows one to drive it successfully in the long term at a higher voltage?

[Alex_Cole]

Here are the pictures I promised. The machine is a little dirty from working on it but I think you will get the idea of the rigidity of this little brute.

1:
pic1

2:
pic2

3.
pic3

4.
pic4

5.
pic5

6.
pic6

7.
pic7

8.
pic8

9.
pic9

Let me know what you think my best options are.

Thanks

AC

[ger21]

Originally Posted by wildcat ger21 - Forgive this naive question but you are saying that a motor rated for 2V should be driven with 20-40V? I am confused... if the motor is rated for 2V what allows one to drive it successfully in the long term at a higher voltage?

Not sure how to explain it, but a chopper drive like a Gecko or Xylotex "regulates" the voltage so as not to damage the motor. The higher voltage is necessary to keep the rated current flowing through the motor at higher speeds.

[Alex_Cole]

having seen these pics would you guys recommend replacing the motors or should I try to work with what is already there. In the pictures you can see the X axis motor mount still has the origional driver card attached. The Y axis picture has the driver card, motor, and motor mount plate removed.

Thanks

AC

[athomas]

Originally Posted by wildcat ger21 - Forgive this naive question but you are saying that a motor rated for 2V should be driven with 20-40V? I am confused... if the motor is rated for 2V what allows one to drive it successfully in the long term at a higher voltage?

The motors are actually current driven devices. The Driver board (Xylotex and others) limits the current to a safe value that the motor can handle without burning up. It doesn't matter what the voltage is. As the current increases to its regulated value, the internal reactance (resistance) of the motor causes a voltage drop across the windings. At a constant safe regulated dc current input, the motor voltage will never rise above the rated value of the motor, no matter what the starting voltage is at the controller.

In summary, the voltage is the amount of push to get the current into the motor. The higher of a voltage you use, the faster the current gets to its rated value and the faster the motor responds.