Re: [CAD_CAM_EDM_DRO] PIC DRO stupid question #3
Posted by
ptengin@a...
on 2000-04-07 16:19:43 UTC
In a message dated 04/06/2000 7:44:42 PM Hawaiian Standard Time,
jmelson@... writes:
<< I really doubt this would work. The gratings would have to maintain a
phase
shift over the entire length of the encoder, to a small fraction of one
line pitch.
That would be VERY hard to do with glass scales, impossible with mylar
films.
Let me ask this risking flames and all. If somebody has access to an
accurate mill, could we not "engrave" a glass scale by dragging a stylus
through a preapplied film? Many industrial machine are accurate to 50
millionths. If we could scribe a scale to 1000 lpi, then you could get 4000
ppi? The stylus would need to be about .0005 to .0008 inches wide. A common
needle?
That proposal of a multi element read head would be the neatest way to
increase resolution on a low res scale. The mounting of two ready made 20
dollars heads would be much faster plug n play wise.
Peter
THRD, Inc.
jmelson@... writes:
<< I really doubt this would work. The gratings would have to maintain a
phase
shift over the entire length of the encoder, to a small fraction of one
line pitch.
That would be VERY hard to do with glass scales, impossible with mylar
films.
>>Jon,
Let me ask this risking flames and all. If somebody has access to an
accurate mill, could we not "engrave" a glass scale by dragging a stylus
through a preapplied film? Many industrial machine are accurate to 50
millionths. If we could scribe a scale to 1000 lpi, then you could get 4000
ppi? The stylus would need to be about .0005 to .0008 inches wide. A common
needle?
That proposal of a multi element read head would be the neatest way to
increase resolution on a low res scale. The mounting of two ready made 20
dollars heads would be much faster plug n play wise.
Peter
THRD, Inc.