Re: [CAD_CAM_EDM_DRO] What should I expect with CNC

On Tuesday 17 September 2002 12:02 am, you wrote:

> The last time I posted, I was having problem getting the current to the
> steppers. I have now built a power supply that is providing 35 v at
> idle, to 29 v when all 3 steppers are moving. I am using a 10,000 mfd
> cap. I am thinking this is enough. ??

The formula (generally) is:

(uF) = (80,000 times I) / V

Since I don't know I (amps), I can't tell if it's enough, but my guess is
that it is. That said, a 20% drop from no load to full load isn't good. I
need to know how the voltage was measured, the specs of the motors, and what
parts are in the supply to figure out anything more.

> My observation is that while at the
> extreme of each axis, I have notice an increase in resistance. Using
> Jog, on the X axis, I can not exceed much more then 25 mm and 215 mm,
> by the scale on the machine. On the Y axis, I am limited to 0 to
> 120mm. At the 0 side, I can usually jog the machine to this machine
> without any problems, but I have noticed an increase in resistance by
> hand. The Z axis, oddly enough, doesn't seem to loose any steps. It
> works from 0 - 160 mm. The only limitation is at 160 mm, is my own as I
> am afraid of running the slide off of the lead screw. More on this
> later.
>
> My question. Is this normal for the Sherline ? Or should I need to
> adjust something ? Or, should I work around the stiffness by allowing
> less working area in the G-code. Did I get the right size (oz)
> steppers ?

What you need to do (if you've used the factory motor mounts) is to remove
the motors, loosen the two screws that connect the motor mount to the
machine, run the table all the way out in the Y (Y+max) and to the left
(X+max) and then retighten the screws. That'll fix the misalignment that
causes the binding.

I'm guessing the motors are OK.

Matt