Re: [CAD_CAM_EDM_DRO] Re: steppers or servo?

Terry,

For most home shop machines stepper motors are what I recommend that new
members start out with. My experience with cnc routers and stepper motors
has all been good. If the system is designed correctly, you should never
loose steps. I sell cnc routers for Machine Automation. Only their CNC Pro
machine requires a servo system. This is due to the fact that the gantry is
very heavy and a stepper system would not be able to accelerate it fast
enough.

My new cnc router that I am ready to test uses the new 3 phase stepper
motors. I will give a report on the new 3 phase motors to the group as soon
as I finish testing out the new machine.

Bob Campbell

----- Original Message -----
From: Terry Ackland <hexagon@...>
To: <CAD_CAM_EDM_DRO@egroups.com>
Sent: Saturday, July 08, 2000 4:14 PM
Subject: [CAD_CAM_EDM_DRO] Re: steppers or servo?


> ---for myself and many hobby machinist we are faced with a list of
> compromises ranging from the cost to the weight we are prepared carry
> down the basement.
> I have used steppers on a home designed special purpose machine for
> the last 2 years and I find steppers to be perfectly repeatable if
> used within their range. If you can make one part that measures out
> as designed on a stepper equipped machine you can make thousands.
> Regarding servos. In my day job I chase tenths around on a surface
> grinder that is equipped with a servo down feed. If the wrong
> dimension is typed in and the wheel crashes into the piece, the servo
> system does not recognise the new position with any accuracy!
> There are 2 alternatives that I have tried to prevent lost steps and
> that is larger motors or gearing down and they both work.
> The greatest problem with a home built cnc machine is finding enough
> work to keep it busy and for also for me it is the noise of high
> speed cutters and dust which really worries me.
> Terry
>
> CAD_CAM_EDM_DRO@egroups.com, "Steve Carlisle" <quatsein@i...>
> wrote:
> > One reason people use closed loop servo system is because
> > it does not loose it's position. A good stepper-servo theory
> > source is listed below,
> >
> > www. linuxcnc.org
> >
> > and look under the Compumotor link.
> >
> > Steve
> >
> > ----------
> > From: Terry Ackland <hexagon@o...>
> > To: CAD_CAM_EDM_DRO@egroups.com
> > Subject: [CAD_CAM_EDM_DRO] steppers or servo?
> > Date: Saturday, July 08, 2000 6:14 AM
> >
> > Hi,
> > Computer printers use stepper motors and they run forever with
> > incredible accuracy. A hobby nc machine will also have the same
> > repeatability as long the motors are not forced into missed steps,
> > right?
> > Servos can also be forced into missed steps so the advantage over
> > steppers must just be the extra speed to return to the home
> > position?
> > Terry
> >
> >
> >
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