Re: [CAD_CAM_EDM_DRO] Re: Re: Digitizers, Renishaw (for bill phillips)

>Piezo's have rotten temperature and moisture stability. (need frequent
>calibration)

Maybe that's why the manual for the Roland machine specifies specific
temperature and humidity ranges (41-104 F, 35 -85%). But it doesn't say
anything about recalibrating.

>Of course I may be being too pesimistic, if your are prepared to accept
>sensible accuracy levels it may just work. Any idea what accuracy Roland
>claim?

Taken directly from my manual, Rolands specs are:
Sensor: Active Piezo Sensor for detection;
Scanning method: Contacting, mesh-point height-sensing;
Scanning pitch: X/Y axis .05 mm - 5 mm (.002 -.20")...operator selectable in
.05mm increments;
Z axis .025mm (.000984")
Scanning speed: 4-15mm (1/8 - 9/16") /sec.
Probe length: 60mm (2-5/16"), tip bulb dia. .08mm (.00315").

The probe extends down from a housing that's about 1" square...plentty of
room in there for a 10mm dia. "buzzer".

>Any idea where small piezo's might be unearthed from? I would guess the
>smallest buzzer I have would be around 10mm diam. Too big for a probe tip.

I'm not sure about the pizeo's but you can get proximity switches with
operating distances as small as .03 mm (.0011") these could easily be
mounten in the top of a probe housing to detect movement of a small diameter
probe.

Also, there are some extremely tiny fiber optics components available that
would allow building a probe in such a way that any interruption of the
light beam (caused by any movement of the mechanical probe, would provide a
useable electrical signal.

Smoke