I have one of these laser-center finders - best money I spent in a long
time.
They're more than just a laser-pointer (which produces a massive dot),
instead they have a *teensy* little hole at the bottom
through which the laser diffuses. The result is a very, very, small dot
(about 0.1mm or less) - this is usually accurate enough to get you to
close within half of this, as you guage the intensity of the beam as you
jog over the edge of the work. Have a black marker handy and mark the
metal first and the dot is reflected less, and thus appears much smaller.
A contact tool may be better for milling, particularly CNC-milling, as
unlike the laser the width of the tool is known - and you could hook
the contact sensor to your CNC system, so the computer can actually hunt
for the edges and set coordinates for you.
But, for a lot of tasks, the laser is more than accurate enough, its
certainly very painless.
And, the laser makes easy something which is not possible with a
touch-probe: setting the center cutting height of your lathe cutting
tool. Just pop the laser in the head/tailstock and align to the beam. I
really do wonder why I fussed around with that sort of thing for so long
before.. :)
Regards,
Abby
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On Thursday 12 April 2007, Michael Taglieri wrote:
Heinlein is to a typical science fiction writer what, e.g., Saul
Bellow is to a typical novelist. In other words, he uses the SF
genre as a setting for discourse in philosophy, sociology, politics.
religion, and many other subjects. Read his masterpiece, Stranger in
a Strange Land, and you'll see what I mean.
I'm quite well acquainted with Heinlein :-) and grok where he was coming
from with a lot of it. I think I have read everything he ever wrote
including the stuff toward the end that got published ONLY because he
was Heinlein (Like Piers Anthony who I am convinced got paid by the
pound :-). One of the first books I read by myself was Starship
Troopers, not at all like the dreck movie that came by recently. I
guess I have a better imagination than hollyweird can project :). He,
probably more than anyone else, is most responsible for the interest
sets that I do have.
Back to the topic, how is a laser edge-finder supposed to work and
what advantage does it have? Suppose you get your final design so it
projects a nice, narrow, crisp-edged beam. What does the beam do
when it touches the edge? Designs that make an electrical contact
and turn on a light bulb when the tip touches the edge seem to have a
clear advantage because they eliminate any need to watch the tool and
see when it touches. With a laser it seems you're back to using your
own judgement, just watching a laser beam instead of a solid object.
How is that better, or does a laser beam actually DO something when
it touches the edge?
Probably easiest to point you at this:
<>
Rather than praddle on about something I am still working toward fully
understanding myself. Two things attract me to it, one you don't have
to stuff your fingers potentially into harms way and you don't have the
potential of breaking something if you are in a hurry or klutzy :).
The one I built works but there are aspects I am still experimenting
with and trying to understand / work out. Fun :-). At the moment I am
working toward beam quality and alignment issues, I'm not happy with
where I am at the moment.
Take care, Vikki.
--
Victoria Welch, WV9K/7
"The people came to realize that wealth is not the fruit of labor but
the result of organized protected robbery." -- Franz Fanon
