I'll need to conduct testing, thanks for the info. I may have been
mistaken.
Jean-François
Le 08/03/2022 à 10:09, gene heskett a écrit :
On Tuesday, 8 March 2022 02:16:38 EST jeanfrancois wrote:
Hi, goog day
Interesting, we areworking on the development of 3D printer, although
it's using an uncalibrated magnetic sensor, I haven't yet tested its
accuracy. It was said .1 is difficult to reach with this, and instead
some use a contact probe for the Z homing purpose.
I find it surprising that you make such a statement. My Prusa MK3S+ has
no home switches on the twin z screws, using an inductive prox sensor on
the head assembly for everything. The bed does not even have leveling
screws. Any unflat error is mapped by measuring the bed at 49 places on a
grid before every print, including z screw sync and compensating by
useing that measured map as the zero reference as it moves during a
print.
Regards
Jean-François
Le 08/03/2022 à 02:12, gene heskett a écrit :
On Monday, 7 March 2022 15:32:57 EST jeanfrancois wrote:
Are ultrasonic sensors doing the job in that tolerance ?
Some are. but there is a problem in the focusing the sound into a
tight enough beam to only measure the target, is actually a
physically large problem. So a real tight beam, similar to a red
laser pointer, takes a rather large apparatus. Impractical in the
average machine shop. Much better to use a little one for under a
couple inches as a limit switch, but inductive switches are much
better suited for that job. And in the current tech as an example, I
have a BIQU BX printer that reads the flatness of its steel build
plate before starting each print, records the differences in it
height at 25 locations on the bed, and then uses that error mapping
to naintain a nozzle to bed spacing of .12mm plus or minus .01 mm
anyplace on the bed with the same sensor used on the prusa. I have
a Prusa MK3S+ that measures 49 places on a similar sized bed. The
BIQU BX at $550, beats the pants off the $800 Prusa for quality of
output. The Prusa fills the vacant inside of a cylinder with hair,
the BIQU is clean and smooth. Could be a cura setting difference,
or even the precursor to a thermocouple failure that currently has
my Prusa on the injured list. Worse, Prusa does not have the part
and hasn't had it in several months. And does not appear to care,
and that does upset me.
Take care and stay well.
Jean-François
Le 07/03/2022 à 21:01, gene heskett a écrit :
On Monday, 7 March 2022 12:44:21 EST Thaddeus Waldner wrote:
Hi,
I’m looking for a laser distance sensor with about 1-3 thousandths
resolution and about a 5-10” working range. I wouldn’t mind buying
a
used unit.
1. I didn't know they came in that high a resolution w/o needing a
quorum of the US Senate to authorize the payment, then signed by
the
President.
If you want to know why, calculate the time difference of that 3
thousandths of an inch increment, remembering that it has to travel
out, and back to the measuring device, equal to C/2 in speed. You
will I suspect will come up with a very small fraction of a
picosecond.
Interferometry can measure that change, but the mod function to
detect
the individual null and count it has to start at zero, or a known
micron sized distance before it can count the nulls passing by as
it
moves from zip distance, back to your point of interest at a 12"
max
range. Moving slow enough to count, will take a 2048 bit counter
and
several days.
Technically, we can do it but you'll need a couple of dump trucks
full of gold to finance one neasurement. We can't yet buy a
calibrated answer in 10 milliseconds for a $500 bill. Someday?
Maybe, but it may take a new method to be invented.
Does anyone here know of some brands/ models to check out?
Google has pointed me at some Acuity products but I wondered if
there
were other options besides that.
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Cheers, Gene Heskett.
_______________________________________________
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Cheers, Gene Heskett.
_______________________________________________
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[email protected]
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Cheers, Gene Heskett.
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