Re: [CAD_CAM_EDM_DRO] Re:Re: Re: 4th Axis Concept (long)

So, Basically you tell the rotary axis to go to home, and it finds and steps off the prox' switch. Then load the material based on that switch location (in this method some parts may need to be jigged for exact repeat locating). When you decide to "run as lathe", use an available M-code to disengage the Servo's Computer controlled power supply, and cross it via relay to the
auxiliary source. Possibly use another code to actually turn on the power for a soft start/ non-contact burning Start-up.

At the end of the "lathe mode", toolpath code dictates the disengagement of power to the servo and restores power from the Servo Amplifier/Driver. Toolpath code then tells all axis or at least the rotary to "seek Home". This IS possible via toolpath code with FlashCut, not sure about others. When it finds the proximity switch it will be in the correct spot. Correct ? Then business
as usual 4th axis stuff.

The 2 things I do not really like (man, I am hard to please) is (1) Indexing the part AFTER setting Zero............ Not the worst, but could be beneficial to set it after for pre-finished parts.

and (2), now I would have to learn about servos ! (Oh, honey,...... I need MORE money!)

Seeing as how I am really Servo-Dumb, What, if anything would I need to be concerned about when disconnecting the Servo from the Servo Driver ? Any sudden "no load" situations ? Obviously, something needs to be disconnected on the "feedback" circuit ! How will that react to a disconnection ?

How does one go about sizing a Servo for the application ? I will have to run a mixed environment, 3 steppers, one servo.
This technique would fit real nice into that little Ryobi Lathe.

Thanks,
Chris L

IMService wrote:

> > Date: Mon, 06 Aug 2001 17:04:12 -0700
> > From: Chris Luebke <datac@...>
> >Subject: Re: Re: 4th Axis Concept (long)
>
> >I am assuming the Servo when acting as a traditional motor will need to be
> >powered from an auxillary supply and not thru the Control systems supply chain.
> >Some Relay work there........I'm not sure how we'd get this lined up using
> >Flashcut, Yeagers CNCPro, Master5, Kcam and controls as such. This is the market
> >that it needs to operate in. Given that, it probably should stay stepper
> >orientated at first. It would be *very easy* to control with an "indexable
> >clutch" and any typical step/dir control on the market because there would be
> >nothing proprietary.
>
> Chris, this is standard start up for a CNC machine. "Machine Home". After you set a zero, you enter the work offset as distance, or in the case of a rotary as an angle from machine zero. You would just have to home the rotary after using the spindle as a lathe, and call out your work offset.
>
> I know that Ahha has been used on some woodworking lathes with this kind of setup(with the servo motor). I helped a guy out a year or so back in understanding how to program the C axis with it(actually W, but I was advising the software Cad-Cam side only, and technically it is a C-word). I don't know if they did it themselves (Ahha), of if it was through a distributor.
>
> Depending on your accuracy requirements, a simple prox switch with a bolt head may be enough to reset the rotary. Shopbot uses something like this, and I guess that it repositions to within about .005 inch or so. On a router and with woodworking this is usually plenty good enough for the kind of horseshoes being played. The wood may warp more than that by the next day anyway.
>
> Best Regards, Fred Smith- IMService
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