Gecko Drive Problems

[sandefuj]

Any body use any thing other than Gecko 320’s to run their CNC mill? I have now killed two. I was hoping to find something more robust, or should I expect to replace one every six months or so? Any comments or advice would be appreciated.

Jay

[WayneHill]

You killed twice already and looking for more victims? What is your application, setup, and how did you kill them? My 320's have lasted for years under continuous use.

[sailandoar]

I killed one and the warranty was long gone..... Gecko said send it in so they could postmortem and at the same time they sent me new one, right away. That's the kind of stuff I continue to hear about gecko drives. TOPS for service!!!

[sandefuj]

Sorry, I did not mean to sound like I thought it was Gecko’s fault, I’m sure it is my work that is at fault. The first one that died was the Z axis you can read my post titled Z Axis Running Away, on my browser it is on page four now. Basically when I turned on the machine the Z axis would chug down pause then chug down more. Replacing the Gecko fixed that problem. The new problem happed yesterday I was cutting a part, it had been running for about two hours continually cutting deep pockets when Y faulted. Now the Y Gecko is dead, I switched the X and Y Gecko’s to test now X is dead any Y seems to run fine, of course I did not test for two hours. The only real clue as to why, is that after the fault, the Y motor was super hot; the X motor was hardly warm. This is the first time I have noticed the Y being warm and never so hot it would burn you to touch. The only thing I have checked is how hard or easy it is to manually turn the axis by hand. Both X and Y seem to turn the same, its firm but smooth on both turning the little black knobs. Later today I was going to check the full range of the Y to see if there are any tight spots or binding. Once again any help or suggestions would be appreciated.

Jay

[sailandoar]

I have noticed from personal experience and a couple of years of reading gecko related postings that Gecko (Mariss Freimanis) is both EXTREMELY knowledgeable and EXTREMELY helpful. I suggest you write up your experiences in as clear, organized and detailed a fashion as you can manage and send it to him. When a similar Gecko tragedy happened to me I sent digital pictures along with some test data to help to see what was going on.
The worst is that it will help you better understand what happened to avoid it happening again in the future and the best case might be replacements drivers and some sage advice/comments.

[mlaws1172]

Jay
If you need info. quick, just give them a call at gecko. They are great to work with.
mike

[Mariss Freimanis]

The G320 cannot make a servomotor hot. Only a gross overload can make a motor hot. An overloaded servomotor will burn itself up. The resulting damage and short circuiting in the motor then destroys the drive. Any DC servomotor that gets more than slightly warm is a motor in serious trouble due to overload.

Mariss

[sandefuj]

Thanks Mariss. I order two new 320’s today; I think I will send the dead one back just too hopefully get more info on what caused the problem. Anybody got any ideas on what may have caused the overload of the motor? The only thing I have checked is that I can turn the Y axis by hand for the full range and I did not feel any tight spots, just firm the whole way. The part I was cutting should not have put any more stress on the Y axis compared to the X, and the X motor was barely warm. I’ll clean every thing up tomorrow and do some more testing.

[SMW Precision]

Originally Posted by sandefuj Sorry, I did not mean to sound like I thought it was Gecko’s fault, I’m sure it is my work that is at fault. The first one that died was the Z axis you can read my post titled Z Axis Running Away, on my browser it is on page four now. Basically when I turned on the machine the Z axis would chug down pause then chug down more. Replacing the Gecko fixed that problem. The new problem happed yesterday I was cutting a part, it had been running for about two hours continually cutting deep pockets when Y faulted. Jay

Jay,

You did not mention you had an IH mill. One of the attributes of that mill is an extremely good heatsink for Gecko drives. Early versions of the IH mills did not have that heatsink and fan cooling system. When Aaron made that change drives now seem to last indefinitely.
You explanation of problem seems similar to reason why heatsink. cooling system was added.

[sandefuj]

Yes, I have an IH mill; it was according to Aaron the last mill and CNC kit he sold. I do not think heat in the controller box is a problem, I’m using the heat sink’s and fans that came with the kit plus I have two big fans at each end of the box that keep a really good continuous air flow across all the components. Thanks though.

What I’m most worried about is that I over tightened the Y axis ball nut, I really do not want to take every thing apart to readjust the nut. Do you think the ability to turn it by hand means it is not over tight?

[SMW Precision]

Originally Posted by sandefuj Yes, I have an IH mill; it was according to Aaron the last mill and CNC kit he sold. I do not think heat in the controller box is a problem, I’m using the heat sink’s and fans that came with the kit plus I have two big fans at each end of the box that keep a really good continuous air flow across all the components. Thanks though. What I’m most worried about is that I over tightened the Y axis ball nut, I really do not want to take every thing apart to readjust the nut. Do you think the ability to turn it by hand means it is not over tight?

Did you follow Aaron's procedure for tightening the ballscrew? It was use of an allen wrench and yields about 90lbs of torque. Also in operation are you showing any fault lights in Gecko drive operation?
Then there is always the question on Gib setting as well as motor tuning. You want to get this resolved before burning up a motor.
Give Gene a call at Industrial Hobbies; he will get you fixed up. He has been outstanding in support.

[sandefuj]

I talked to Tommy today at IH and he thinks that it was motor tuning that caused all my problems, I agree. During the cutting of this part I did notice that the Y axis knob was shaking when the Y axis was not changing, constant Y, changing X. Due to my ignorance I did not think it was a big deal and I would look into it after the part finished, part never got finished. I guess in the future I will be more careful. When I was building the mill I spent a lot of time getting each motor tuned just right, what I thought was perfect. I did not know you need to check the tuning regularly, now I know. I won’t make this mistake again; but I will probably make all new mistakes in the future. Thanks everyone.