Movement in XY

[mike_greschuk]

When my Bot moves in XY faster than 7 ips it chatters and shakes. Any imput would greatly appreciated
Thanks,
Mike

[dlcw]

Mike,

When my PRSAlpha 96x60 jogs at higher speeds it tends to make noises also. I was told by Shopbot that since our machines don't have motor compensation circuitry (I think that's what they called it) there will be certain speeds that it will create harmonic vibrations and make noise. It mostly happens in my Y movement but sometimes in the X as well.

I've tried adjusting and tightening everything and it makes no difference. I was told there is no harm being done, so I just live with it.

Don
www.dlwoodworks.com

[Gary Campbell]

Michael...
IS your machine a standard or alpha?
Gary

[mike_greschuk]

Hello Gary,
It's a Alpha I can surface at 10ips just fine but when it's done it returns in X+Y at the same time and wants to make noise.It sounds and looks quite ugly. But it sounds and runs very smoothly at 7 ips. Don thanks for your imput. Sounds like I'm not alone
Mike

[Gary Campbell]

Michael..
My machine makes some of those strange growling noises, but only at slower speeds. I also assume its harmonics, but am not sure.

I do not get any of those sounds above 4ips on any axis.

Can you isolate the noise to a single axis and speed? Most surfacing routines use a single axis move at a time.

You say 7ips. IF you jog @ 7ips is it any different sounding than if you move at the same speed? What about moves/jogs that are 2 axis moves or jogs? Is it more pronounced during the start and stop (ramp) section or in the middle of the motion?

For testing puposes, you should be able to jog up to 25ips and move up to 10ips. Try different combinations of speeds and angles to see if you can isolate it to one axis, or in the case of the X, to one motor. Try moves/jogs that are 1 2 3 or 4 times as long in one axis as they are in the other.

Make sure all connectors into the motors and drivers are secure. Check your comm rate.
Gary

[mike_greschuk]

Gary,
It's more like a stuttering movement. It will move in either direction @ 10 ips but when both axis are in motion 7 ips is the best it can do. I will try some of your suggestions tomorrow.Could you elaborate on the comm rate. Is Jogging @ 25 ips right??
Thank You,
Mike

[Gary Campbell]

Michael...
To test the comm speed, go to C:\Program Files\ShopBot\Diagnostics and run the "SpeedTest" with SB3 closed. You should be in the mid 70% range.

Yes, at least on my machine I have the jog speed set at 25ips. I have softened the jog ramps a little, but for your puposes, you can do some compound moves at speeds up to that. (jogging)
Gary

[mike_greschuk]

Thanks for the great info Gary! I usually stop it when it makes the hideous noise. I'll try higher jog speeds tomorrow and check cables and connections
Mike

[eaglesplsh]

Under specific conditions, I get harmonic noise when my Alpha jogs at high speed as well...

When I first heard the noise it sounded to me like gears grinding - definitely caught my attention and had me scratching my head. After some investigation, I found that the noise was made when I jog long distances on a slight diagonal, that is when the X axis is moving a long distance at high speed while the Y axis is moving a short distance at slow speed. (or the other way around.)

I talked to Ryan at ShopBot about it and he confirmed that it was a regular occurrence and that it wasn't doing damage to my machine.

It doesn't happen at cutting feed rates and I don't see or feel any vibration in the gantry while the noise is happening during jogging, so I don't worry about it anymore.

By the way, my grounding is top notch, my diagnostic speed test shows high 70's, my motor cables are run with a loop per the directions... nothing seems to have an effect on the noise.

[mike_greschuk]

Looks like a communication issue. ran the test. 56% checked cables everything looks tight. Any troubleshooting tips or should I get a IT guy to check it out
Thanks,
Mike