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Author Topic: Problems threading on the lathe  (Read 330033 times)

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Re: Problems threading on the lathe
« Reply #380 on: May 26, 2009, 03:40:18 PM »
thanks , deleted usb hub and reinstalled , recognized smooth stepper. Still loosing com with SS after about 5 minutes. Wife has ordered me another computer try

Offline Hood

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Re: Problems threading on the lathe
« Reply #381 on: May 26, 2009, 03:43:51 PM »
Double check to make sure the Power saving is  switched off on the root hub that the SS is connected to.
Hood

Offline ART

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Re: Problems threading on the lathe
« Reply #382 on: May 26, 2009, 06:47:56 PM »
Hi Guys:

  New version of threading plugin. This is for Chip , I need to know see a snap of the scope capturing
about 1024 samples.. There is a new DRO to show what sample number is causing that wrong minimum time
reading..

  We ARE getting very close it seems, numbers are looking good all round, next stage will be actual threading
correction algorithm being turned on if this all works..

Thx
Art
Re: Problems threading on the lathe
« Reply #383 on: May 26, 2009, 06:49:50 PM »
reloaded xp serv pack 1 on the mill and loaded the latest drivers from the manufacturer and its now communicating with the SS again and running fine.

I did the same on the lathe and it now communicates fine for two or three parts and then looses communication if I get chatter from the parting tool on larger parts .

I am unsure why this is happening or how to resolve. the VFD for the spindle is on the wall aprox 5 foot behind the machine , the computer is at the front of the machine and the usb cable runs thru conduit to the ss which is in a very heavy steel cabinet at the back of the machine. I am guessing the vfd is now the problem. If the door is open it will loose contact with SS as soon as the spindle starts. With the door closed it only happens when the tool chatters.  On small parts where no chatter is present it will run for quite a while. The control wire for the vfd runs into the same cabinet as the SS and comes within aprox 2 feet. The cable is sheilded and grounded but there are 6 wires that are exposed for aprox 4" that run over to a terminal block.  Could this possibly be my problem and how would I resolve?

Offline Chip

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Re: Problems threading on the lathe
« Reply #384 on: May 26, 2009, 07:03:36 PM »
Hi, Art

Get you some Pic's in a bit.

Chip

Offline Chip

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Re: Problems threading on the lathe
« Reply #385 on: May 26, 2009, 08:08:52 PM »
Hi, Art

Hear are some Pic's of my stable computer, More to follow.

Edit: As before with number of Slot's above 80 Threading will not Start on this computer.

Chip
« Last Edit: May 26, 2009, 08:41:03 PM by Chip »

Offline RICH

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Re: Problems threading on the lathe
« Reply #386 on: May 26, 2009, 08:42:18 PM »
panacea....m,
Been following your thread some, and still confused by it.
I don't know if you have one problem or two problems, namely computer or noise / rf or even a combination of the two.
1. The ss should not be loosing communications with PC when VFD  / motor and other influences
   are removed from the picture. That has to be achieved, got to start somewhere.
   I would recomend divide and conquer. If that's in place then you can in a very disciplined way go about identifying
   another culprit if there is one.
2. Noise / rf can be a real bitch. VFD and motors are prime sources of it. Shielding is meant to keep a noise out or inside the protecting conduit. You can for example, inductively pick it up and makes sure it stays mixed by keeping it inside a shield. Or you can provide a path for the noise \ rf along the shield and get it ito the grounding.  Bitch is you can't see it, you can measure it somewhat to get a mental picture of intensity, and then use some logic or "black magic" to cure it. So sometimes easy, or logical, or complex, or black magic .....just a bitch.

You change one parameter , like opening the VFD cabinet, and you have a whole set of new possible cause and effect conditions. The motor starts and creates an atomic bomb of noise, or the noise just gradualy builds from it and evently affects something.  Sometimes the only way to get rid of a electric field is  shut it down so it resets back to zero.

Divide and conquer,
 RICH

Offline Chip

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Re: Problems threading on the lathe
« Reply #387 on: May 26, 2009, 08:54:32 PM »
Hi, Art

On my non stable computer, Threading will start at above 80 slots.

First 2 pic's with stable Pulse Frequency, 3'rd with mouse movement, 4'th without mouse movement.

Can you set the scope to stay on top.

4 more pis's one post UP, Of my stable computer.

Chip
« Last Edit: May 26, 2009, 08:58:18 PM by Chip »
Re: Problems threading on the lathe
« Reply #388 on: May 26, 2009, 09:36:40 PM »
Thanks Rich , my problems with the SS have been multi fold . I was having USB driver related problems which I eliminated today with a fresh instal of XP pro and new drivers from Dell .

Now that I have eliminated the USB problem I can succesfully turn parts for quite a while until there is a heavy load on the spindle and I get interference .
I can turn , thread and part off small alum parts (sub 2" diameter ) with no problems as long as I dont take heavy cuts , as soon as I take a heavy cut I can hear that audible high pitch from the vfd and thats about the time I loose connection with the SS. As long as the cabinet containing the SS is closed I only loose comm when there is a fair load on the spindle.
If I open the cabinet door which faces the vdf I loose comm instantly .
So now that the USB issue is fixed I am just down to chasing down this interference issue from the VFD. Tommorow I will be encasing all the wires to and from the vfd in metal conduit. Hopefully this will help .
Would it help to put the SS in an enclosure of its own? Its in the main cabinet with the servo drives and BOB, plc etc which is aprox 3' wide x 4' tall. There is an identicaly sized cabinet beside the control cabinet that contains relays , control for the hydraulics and a a few transformers should I try moving the VFD from the shop wall into this cabinet ?  I can move a few transformers around a squeeze it in if it might help?
I am just not sure if the noise issues from the VFD are being emmited from the unit , its wiring or a combination of both.  Should I be looking at isolating the source of the interference or insulating the SS from it .

Ill stop rambling on , just feel I am getting very close to finishing up a year long project . Thanks Richard

Offline RICH

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Re: Problems threading on the lathe
« Reply #389 on: May 26, 2009, 11:39:39 PM »
pana....m,
There was a good post where grounding and  noise was discussed, but as usual can't find anything ( in the last year ),and with a similar setup problem,maybe a mill and and eventualy a proper ground system was put in and all was good. Would be worthwhile reading for you. The best i could do is talk
about noise / rf  interference and give you some experience  / guidance to go by. Otherwise i will be writing a book here and driving you crazy.  It's your nickle just send me a PM. Post a few pic's.
Elimination of the problem is prefered, minimize, try to control, it's a matter of degree.
RICH