Re: [CAD_CAM_EDM_DRO] Orientation was Re: Repeatability of Home switches

mrgamber wrote:

>What is the recommended orientation of the switch?
>
>Should it be in the path of the axis and depress the lever or button?
>or is it better to let it "wipe" the trigger? Wiping seems safer but
>less accurate.
>
>

The setup should always be designed in the event that a machine has no
idea where it really is decides to go anywhere near a home switch, that
it does not smash the switch to bits. I would tend to agree that hitting
a mechanical swtich "head on" might be more accurate, but who knows ?
The first really important question is what repeatability do you need at
the switch ? As Doug pointed out just earlier, Does ones machine
resolution drop way lower than your switch can detect ?

I'd sure hate to think that some are overly concerned about home switch
locations, settings and resolutions on any machine that does not have
the "other mechanical 'Guts'" to make a fine switch matter. Everything
has to extremely "tight" in this regard to even get to .001". That
might rule out homemade antibacklash stuff that needs occasional
adjustments.

Back to your question though, My favorite technique is somewhat twofold.
I'll hit a switch "headon", but then back the switch up with a small
hydraulic dampener to absorb the impact that will occur if the machine
is "lost". The dampener protects the switch.

The only other safe bet is to allow the switch to wipe or swipe, and
have a goodly amount of space for the "coasting" before a fixed
"deadstop". I will use "swipe" techniques on a Z axis before an X-Y, as
it is usually a spot that is "set" for jobs anyhow.

I'd be confident that a swipe technique is fine for most applications,
as long as the machine can transverse the contact point effectively.
That can be sometimes tricky. But, it depends on what your making, how
your making it, and if you need to be concerned about it based on your
needs.

Chris L