johnrpm wrote:I tried with course lapping paste, works well and cuts at a reasonable rate.
Hi John that sounds good i hope it works out .
Heres some stuff i have tracked down which again more than likely is of interest to us all.
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johnrpm wrote:I tried with course lapping paste, works well and cuts at a reasonable rate.
gary wrote:Hi Harry, thanks for those uploads.
I was just wondering if that is the best quality available for Screen 00001.jpg?
Some of the maths is not really legible.
The last one is a bit off topic for this post but it shows a lot of different mirror polygon scanning ways which really interests me .
johnrpm wrote:The last one is a bit off topic for this post but it shows a lot of different mirror polygon scanning ways which really interests me .
Me to Harry, I have extracted a polygon scanner from a laser printer, it has a brushless DC motor, I have it running with help from the tinternet for the scophony system I hope to build one day, I can post some info on getting it to run if you wish.
johnrpm wrote:I extracted it from a kyocera, also got one from an old HP, some laser printers do have a led array, but the older ones seem to have the polygon,
the thing you are looking for is like the image attached, and has the lenses
and mirror, the one from the kyocera need a pulse input to regulate the speed, which I think is very stable, it also has a photocell to detect the end of each sweep, which makes it useful for our purposes.
I will take some images and post them.
gary wrote:Here's one I made on my CNC machine - I haven't had time to use it in anger yet, or mount it on a proper spindle, but the approach *seems* sound enough. The mirrors are rear silvered glass.
johnrpm wrote:I think that with a hexagon and 32 lines 4000 rpm is the speed of the fast scanner, or 3000 with an octagon for NBTV, (my maths may be wrong) but for a bigger picture the speed may get high enough where balance etc may be critical, in one of the pdf's Harry posted, scophony had their's at over 30,000 rpm, and had more facets.
Some time ago I managed to cobble together a very crude laser projector using string and sticky tape, just to see if I could do it, I used a pc speaker amplifier for the laser modulation, a laser polygon for the fast axis and a dc motor with mirrors glued on for the slow axis, after a lot of messing about for 4 nights, for a fraction of a second I got sync and the image appeared,
It really was crude but very satisfying, I always intended to do it properly one day.
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