Ok I purchased this unit from K2.

http://www.lynxmotion.com/images/temp/k2cnc.jpg

o KG-2525-G
o 305 oz.in. servos
o 3 axis Gecko controller
o THK Rails and screws
o Colombo 3hp 18k rpm spindle with Delta drive
o Mach 3
o .750" t-slots table

$11,638.99

I have powered it up and jogged it around. It has a horrible growling sound when moved. The Y axis (bottom) is the worst. But both X and Y are very noisy. Also the PID isn't right because both the X and Y axis make a constant wining sound. Again the Y axis is the worst.

I have contacted them and apparently it's my responsibility to verify that this isn't effecting the accuracy. They are telling me a small percentage of the machines have this problem, if it is a problem...

I'm not new to CNC, but it's been a long time. My first machine was really quiet and smooth moving. It was called the CNC Crafter when they were in business.

Am I expecting too much?

Does the hunting sound from the servos indicate a problem?

I also have a bunch of Mach3 questions, but will start a thread in a more appropriate place for that. Looking for feedback good or bad.

Wow!
That's a major spindle.

Ok I purchased this unit from K2.

http://www.lynxmotion.com/images/temp/k2cnc.jpg

o KG-2525-G
o 305 oz.in. servos
o 3 axis Gecko controller
o THK Rails and screws
o Colombo 3hp 18k rpm spindle with Delta drive
o Mach 3
o .750" t-slots table

$11,638.99

I have powered it up and jogged it around. It has a horrible growling sound when moved. The Y axis (bottom) is the worst. But both X and Y are very noisy. Also the PID isn't right because both the X and Y axis make a constant wining sound. Again the Y axis is the worst.

I have contacted them and apparently it's my responsibility to verify that this isn't effecting the accuracy. They are telling me a small percentage of the machines have this problem, if it is a problem...

I'm not new to CNC, but it's been a long time. My first machine was really quiet and smooth moving. It was called the CNC Crafter when they were in business.

Am I expecting too much?

Does the hunting sound from the servos indicate a problem?

I also have a bunch of Mach3 questions, but will start a thread in a more appropriate place for that. Looking for feedback good or bad.

If the servo motors are using G320 servo drives they just might need to be tuned.

http://www.geckodrive.com/upload/G320-REV-7-Manual.pdf


Under the tuning section they explain gain and dampening and noises and such.

I would unbolt one motor unless this voids the warrenty and then run it bolted to something so it can't move and fall on the floor. I would see how it sounds then. This way you can isolate the motor and drive from the rest of the machine.
For $11K plus, I would expect a better explanation other than some units have this "problem"???



Wow!
That's a major spindle.

I agree, I need 2 or 3 for myself, I guess I had better get going on making money.

It's difficult to know if there is a problem from a description, so here is a video of it in action. I will also post another illustrating the whining noise the motors are making at rest.

http://www.youtube.com/watch?v=K8sCPihgVjc

Let me know... Thanks

I will say the cause of that noise is beyond me.

I will also say if I had just spent $11k and the machine made that kind of noise, I would be calling them every day.

My home made router with steppers and mismatched parts is quieter than that.

I did notice that it is noiser when moving both the x and y together.

Mike

Here are two videos, just for the audio, of what the motors are doing with the machine at rest. The first is cycling, but the second is a constant buzzing. It just depends on where the motor is stopped.

http://www.youtube.com/watch?v=viBJ7vVgcLo

http://www.youtube.com/watch?v=yHY7c2Wq9DE

Bottom of page three in the owners manual from my earlier post, there is a section called gain and dampening. It sounds like in the second video that you are getting what is called dithering. The encoder is bouncing between encoder counts rather enthusiastically. The first video may be the same thing but at a slower speed.

I am still not sure what is causing the noise in the videos of the machine moving.
A call or email to Gecko directly may be in order.

The second video sounds like the axis is dithering between encoder positions.

Could there be any alignment problems that happened during shipping?

Bottom of page three in the owners manual from my earlier post, there is a section called gain and dampening. It sounds like in the second video that you are getting what is called dithering. The encoder is bouncing between encoder counts rather enthusiastically. The first video may be the same thing but at a slower speed.

I am still not sure what is causing the noise in the videos of the machine moving.
A call or email to Gecko directly may be in order.

I'm reluctant to do the sort of alignment described in the manual because I'm not comfortable taking stuff apart. That's why I opted for the complete package and not a DIY kit.

The second video sounds like the axis is dithering between encoder positions.

Could there be any alignment problems that happened during shipping?

There were no obvious signs of damage to the shipping crate.

Hi Robot Dude,

I own 3 K2 machines with a similar setup. A few ideas you may consider.

A) Check the alignment of the belts. On one of my machines, the Y axis belt was rubbing.

B) Check the alignment of the Y axis. It is possible during shipment, the nut mount or the rear motor assembly mount may have moved. I think K2 has a document on the process of getting your ballscrew assembly in alignment.

C) One thing to keep in mind, the K2 machines use roller bearings at the end mounts of the ballscrews, which are much more nosier than a thrust bearing would be. It is hard to tell from your video if the noise I am hearing is being amplified from your table. My table is a 4" square open frame steel table. It appears your table is made from wood and would act like an acoustic guitar sound box - making the noise louder than it really is.

D) I would also check as previous mentioned the setup with the gecko drivers. If your servos are stuttering, you will need to tweak them.

--

Best regards,

- Todd Reith

Todd M. Reith - todd@customluthier.com
Custom Luthier - Blueprint for Success!
P.O. Box 1306, Kennett Square, PA 19348 USA
www.customluthier.com - www.reithguitars.com
T: 610.925.2613 F: 610.514.3737

MySpace URL: http://www.myspace.com/customluthier

Hi Robot Dude,

I own 3 K2 machines with a similar setup. A few ideas you may consider.

A) Check the alignment of the belts. On one of my machines, the Y axis belt was rubbing.

Interesting, so's this one. The two pulleys aren't even close to aligned.

B) Check the alignment of the Y axis. It is possible during shipment, the nut mount or the rear motor assembly mount may have moved. I think K2 has a document on the process of getting your ballscrew assembly in alignment.

I will have to look for it. They never mentioned it in my communications with them.

C) One thing to keep in mind, the K2 machines use roller bearings at the end mounts of the ballscrews, which are much more nosier than a thrust bearing would be. It is hard to tell from your video if the noise I am hearing is being amplified from your table. My table is a 4" square open frame steel table. It appears your table is made from wood and would act like an acoustic guitar sound box - making the noise louder than it really is.

D) I would also check as previous mentioned the setup with the gecko drivers. If your servos are stuttering, you will need to tweak them.

Well the instructions tell you the motor has to be removed from the machine as part of the tuning. That's more than I'm comfortable with.

--

Best regards,

- Todd Reith

Todd M. Reith - todd@customluthier.com
Custom Luthier - Blueprint for Success!
P.O. Box 1306, Kennett Square, PA 19348 USA
www.customluthier.com - www.reithguitars.com
T: 610.925.2613 F: 610.514.3737

MySpace URL: http://www.myspace.com/customluthier

Hey nice websites! I like those mini guitars you make! 8)

Well I started looking over the machine very closely. I found six bolts that were not tightened at all. Totally loose. I could turn them by hand.

I tightened them down and it's a little more quiet. I think there is still something going on with the Y axis ball screw though...

http://www.youtube.com/watch?v=GPPd_o9YC1Y

Then there is the issue of tuning the Gecko drives to the motors. It's still hunting...

sorry man, but that sounds like crap- a new machine; what is it going to sound like 6 months from now ( if it's still running) ? a mechanical device, properly designed and built will not have such mechanically induced noise. I think you bought a lot of unfulfilled promises.

one quick thing; you have properly lubed everything eh ?

sorry man, but that sounds like crap- a new machine; what is it going to sound like 6 months from now ( if it's still running) ? a mechanical device, properly designed and built will not have such mechanically induced noise. I think you bought a lot of unfulfilled promises.

one quick thing; you have properly lubed everything eh ?

It's lubed from the factory. It's all over the place. It's only been moved a total of 6 times. No actual use, the spindle hasn't even been wired up yet.

I'm waiting to see what they want to do with it.

Hi Robot Dude

It looks like the end of the screw is bent or machined badly this is easy to see in the last video you can see the pulley wobbling as you can't see everything there could be more than just this by the sound

It might have been hit with a forklift during transportation.

Maybe you should make a damage claim.

Jeff...

I've received a reply from K2. They have committed to make it right. I will reply later with more info.

It might have been hit with a forklift during transportation.

Maybe you should make a damage claim.

Jeff...

No that's not it. There was no visible damage to the shipping crate.

Robot Dude,

The shaft pulley wobbling is not good. Send the video to K2 and get a replacement pulley. It could also be the shaft...

( Sorta looks like the DIY pulley on my machine :)

Wayne

I have received word from K2. They would like to send me a new ballscrew assembly for the Y axis. I think the original is bent. If that doesn't fix it then whey have agreed to take the machine back for a rebuild. It's going to be 3 weeks before I get the new ballscrew assembly. I didn't want to have to do the work myself, but it should be faster and cheaper than sending the machine back. It's progress anyway. :D

Good news from K2. Awesome looking spindle! I know it can be a pain to be so excited about getting the machine just to have to turn around and send it back for some repair.

I have one of the first K2 3925

My X axis is also gritty and was sent out a new ballscrew. My first was really bent.
I was never able to get it quite. I think the long screw must bend enough to cause some noise tied in with the balls in the nut not moving well. I played with it for a while but never got it quite. It does not seem to hurt the performance other than I don't care for the noise. Y and Z are silky smooth.

Maybe someday I will get a newer nicer ballscrew for it. For now it works :)

taus
www.cuttingedgecnc.com

It's going to be 3 weeks before I get the new ballscrew assembly.

3 weeks??? Are they serious? I would insist they overnight the replacement part on my 11k machine...

Gary

I would have returned it.

They would have to ship a new one ASAP before I would reconsider.

There are so many machines you could have bought...

C99

What ever did happen with the machine???

I actually, for the first time, got a grease gun and put grease in the linear bearings...to my SURPRISE, my X axis is quite a bit quiter! I would never of guessed. I blamed it all on the ballscrew.. Don't get me wrong it is not like the Y and nothing like the Z but quiter. I would check those too, maybe mine needed grease a long time ago. Huh...

still waiteing for parts?

What ever did happen with the machine???

I actually, for the first time, got a grease gun and put grease in the linear bearings...to my SURPRISE, my X axis is quite a bit quiter! I would never of guessed. I blamed it all on the ballscrew.. Don't get me wrong it is not like the Y and nothing like the Z but quiter. I would check those too, maybe mine needed grease a long time ago. Huh...

I thought you said everything was properly lubed....

I don't remember saying that...more assuming.... but in the number of years I have had mine I have never put more grease in the linear bearings. I will do so from now on. I have sprayed the X and Y axis with WD-40 on occasion.

taus

wd-40 is more of a de-greaser- it evaporates and leaves a residue that collects grime

wd-40 is more of a de-greaser- it evaporates and leaves a residue that collects grime

It's mostly fish oil.
I'd use graphite powder .

It's mostly fish oil.
I'd use graphite powder .

I believe that's an urban legend. The MSDS for WD40 lists 50% solvent, and 15-25% petroleum oil.

Speaking of greases, K2, etc. I just got my K2 in, and was wondering - does anyone use "green grease" ( http://www.greengrease.net/ ) in their anti-backlash nuts? Any issues with using a synthetic there? I use it a lot in other projects, and would like to stick to one lubricant for greasing, if possible.

!c

http://www.snopes.com/inboxer/household/wd-40.asp

CRC Tac2 is the shizzle for any of the sort of machine lubes required.