My take on a stepper damper

[Fixittt]

when you made your dampeners. Did you make the hole for the bearings .015 to .020 bigger then the bearings you put in?

They should rattle a little bit when stitching direction but not much. Remember you have centrifugal force when the motors are spinning.

If your still loosing steps then back down your velocity and accel.

V refs for the first gen ver 4 boards are 3.5 MAX Need to have cooling fans with this.

Like was said above. Many things come into play with lost steps.
here ar the vids I made of my setup and the horrid harmonics.

[ame]http://www.youtube.com/watch?v=9RoOZs9LrYo

[ame]http://www.youtube.com/watch?v=ivDQTeGuduk

[ame]http://www.youtube.com/watch?v=8Am69_F93yA

[grahamshere]

Hi fixitt, Turns out my verf was way too hight, I had an old dial multimeter that didnt work well, My verfs were like 3.7 so that was my problem, now there at 3.6 which is the max for my board. I have 2 motors running at 50 ipm with out looing steps or torque but one I cant get past 25 ipm even off the table so im not sure whats up with that. Hoping I didnt bugger anything up. Graham

[grahamshere]

I meant to say thanks for the vid,s as well and I also meant to say I cant get past 25 ipm then I lose torque. Graham

[Jay C]

Graham, You could have fried the driver for that axis. Test a known working motor on that driver to confirm ... also as a cross check, put the 1 motor in question on a different axis to test that it's not the issue.

Jay

[grahamshere]

Hey jayc, I bet thats what I did, Ill check in the morning to see if I fried it, man thats going to be a bugger if I did. Im sure xylotex can fix it but how long, even 2 week will be a pain, im so close to start working. crap, oh well see in the morn. Graham

[Fixittt]

The faster a stepper motor spins the less torque it has.
With my maxnc I wanted 40 IPM BAD when I first started this. But it would just act stupid.
Granted I couldnt even cut wax at that speed, it was all a mind thing. I finally tuned everything and I am totally stable at 22 IPM and my wax looks great.
I would much rather cut the wax 1 time at 22 ipm rather then try to go faster and waste more time when the machine messes up. Granted with doing jewelry I have thousands of moves that are really small. My average g-code size is 8 megs. Alot of movements!

If it were me, I would back your V refs down to 3.5 or even 3.3 This is because when a stepper is not under power, it becomes a generator and pushes power back thru the board. So give yourself a bit of head room. You dont want to be sitting on the jagged edge of blowing something up. Driver boards are not cheap and its not worth the potential dangers.

Also a stepper will preform worse just sitting on a bench. It needs to have a bit of weight on it to function properly. Do not rely on a testing method that doesnt have force or drag on a stepper motor.

Ohh and when you find a setting in mach3 that is solid. not missing any steps ect. But if you go any higher or faster it starts acting stupid, back the motor tuning down 15 to 20 % from that setting.

[grahamshere]

Hey fixitt, im testing one of my drivers today but I think its buggerd , If I lower my verf any lower than 3.6 like say 3.4 I only get 10 ipm so im sure its toast. Its because I used a crappy multimeter, was giving me a bad reading, I should have realised somthing was wrong when the motors got hot but I thought that was normal, now they stay warm not hot. Stupid me I guess,Leason learnt as they say. Oh by the way im useing acme screws 10 tpi so I should get better than 22 ipm so jeff from xylotex says.Graham

[grahamshere]

Hey guys, Well turns out its my motor, I swapped the axis around and its the motor thats causing the problems, might try and swap the x with the z if you know what I mean till I buy another motor off Jeff. Graham

[Jay C]

should have realised somthing was wrong when the motors got hot but I thought that was normal, now they stay warm not hot. Stupid me I guess,Leason learnt as they say. Oh by the way im useing acme screws 10 tpi so I should get better than 22 ipm so jeff from xylotex says.Graham

Well, now that begs the question "how hot". Too hot and you may have buggered your stepper. This is why I wanted you to test that motor on another driver. Heat demagnetizes permanent magnets.

Jay

[grahamshere]

Hey jayc. Well thats what probably happen then, Because they did get hot before I set the verf properly now they just stay warm to the touch. Guess lesson learnt right. Lucky it was only 1 thats buggerd. Graham
ps: if any body eles is just starting with cnc, make sure your multimeter works properly and do your self a favor, get a digital multimeter. Graham

[jimhat42]

Oriental motor makes dampeners just for this purpose, they are pricey but they work, they are constructed just like good automotive harmonic dampeners with a very viscous fluid almost like silicone and a heavy metal ring. They are bright yellow and look like hand knobs, but they do much more:
http://www.orientalmotor.com/product...EXTA/StAcc.pdf page 11

[Jay C]

Guys, apologies for my recent posts on this thread. It's been a lot time since I joined it and I forgot the post that started it all. So just as a reminder to myself and others here is what Steve originally said and intended for this thread. So Add some flywheels at the very least and turn your Vrefs back to where you want them I'll tell you, the commercial ones I found online range from $42 to $65 ea ... so not much to lose here.

Jay

I have recently been battling with some bad mid range resonance on my x3 mill. I am using a Xylotex 4 axis drive with 425 oz steppers. I had reduced the resonance by greatly reducing the Vref on the drive. However this is a very poor fix as it hurts performance. I looked at several damper designs used on engines. Elastomer, fluid and a pendulum type. I decided a pendulum type might offer the quickest response and be able to absorb a wider frequency range so I gave it a shot. The results are nothing short of amazing. It completely absorbs all resonance and vibration problems I was having. I was able to turn up the Vref to full power without a trace of resonance with the damper installed. Remove it and the ugly resonance is back. It's dramatic how well this damper works. TCI makes a automotive type of this damper for racing and they call it the "rattler". This is because when it is working you can hear the rollers working. It's very interesting to hear this damper work. At feeds where there was usually resonance the damper will be very active with the rollers making noise while they are absorbing the resonance. At speeds when the stepper is in a resonance free operating range it is dead silent. It's easy to make. My design is about 2.45 in diameter with 9 rollers.The rollers have .045 clearance in the pockets. http://i109.photobucket.com/albums/n...rdamper001.jpg http://i109.photobucket.com/albums/n...rdamper002.jpg http://i109.photobucket.com/albums/n...rdamper003.jpg http://i109.photobucket.com/albums/n...rdamper004.jpg Steve