Vrad

[planters]

I want to construct a mega big aperture scanner. I already have the mega big lasers for it.

I am thinking of filling the gap between the 9mm Saturns and Eye Magics and the huge beam directors made by companies like Aerotech.

https://www.aerotech.com/product-catalog/gimbals-and-optical-mounts.aspx?aperture=24


I plan to use four Vrad motors in an arrangement similar to a typical scanner with two orthogonal mirrors, but with each mirror mounted symmetrically between a pair of motors. I contacted Pangolin and I am hoping to get some recommendations for the driver for each axis. I could use any other recommendations anyone here can make. I would like to control each axis with a VERY SLOW 0-5V signal that could originate from say, Beyond.

http://www.scannermax.com/pdf/VRAD1510.pdf

The mirrors will each be 75mm square for a clear aperture of 50mm.

[catalanjo]

Can't you just use the old GS300PDs for this
I have them with 50x50mm mirrors and they work OK - just a bit slow.
Cheers

[danielbriggs]

Any good?
http://www.ebay.co.uk/itm/3316799507...%3AMEBIDX%3AIT
Looks slow but accurate.

[-bart-]

Just a thought, would it be possible / feasible, when working with very big mirrors, to have two vrads handle one mirror ?
Assuming that inertia is you biggest problem, just actuate the mirror from both sides.

[mixedgas]

Planters,
What happened to the very big Cambridges I sold you?

Steve

[dsli_jon]

...The mirrors will each be 75mm square for a clear aperture of 50mm....

Sure, I'd also second Briggsy's and the P'Fessors fine CT-based suggestions, but.. I am also thinking (aside from the mother-honker Dan Ref'd, there..) the Shaft-diameter.. I'd heartily recommend the GS Z-519s, since they've got a Really 'meaty shaft' that should allow you do build an appropriate clam-shell mount for your dinner plates.

Here's a nice thread on them... https://www.photonlexicon.com/forums...Scanning-Galvo

...You could mod / run a 'off the shelf' driver like the CX-660's http://www.ebay.com/itm/GENERAL-SCAN...AAAOSwq7JULZga ..or, use one of 'LII's (see 'Laserist's comments in that thread..) ..We've got Trays of Z-519s, and Several amp-cards.. Lemme know if interested..

Sirs Photonbeam and/or Laserist should be able to better comment on amp-considerations (damping, and such..) with such a 'load'..

fwiw..
j

[planters]

Planters,
What happened to the very big Cambridges I sold you?

Steve

I still have these, but I didn't think they could go that big. Maybe this would work if just slow enough?

Assuming that inertia is you biggest problem, just actuate the mirror from both sides.

This was exactly my original idea.

Jon,
These look pretty small.

Dan,
That's what I'm talking about! But... one motor? This looks like a long road. If Steve thinks I can load down his motors with literally coaster sized mirrors then that might be the way to go?

[logsquared]

I still have these: http://www.photonlexicon.com/forums/...inum-enclosure

Not sure if they will swing 75mm mirrors? Mixedgas might know?

[planters]

Not sure if they will swing 75mm mirrors? Mixedgas might know?

Those are BIG! I'd like to know what he thinks as well. Did you test this at all? Even if it doesn't do a test pattern very well, does it produce a symmetrical movment? Will it hold a point steady and return it? Is it analog modulated so that it might be interfaced with an FB3?

[VDX]

... how fast/slow will you move?

I've tested with ever bigger mirrors on standard galvos until they went useless, then replaced the galvos by servos with pretty high gearing ratio (around 400:1 and spring-loaded to avoid play) to get the angular movement fine enough.

This was meant for material processing and I can mark/engrave with more than 1m/s ... with lower gearing ratio this can be made much faster, if needed.

My mirrors were 'only' 45x40x5mm big, but could be much bigger too, as the servos are sort of 'underchallenged' in this configuration ... have seen a setup for additive 3D-welding with a single 2-axis-scanning mirror with around 200x200mm size, used for a CO2-laser with >2kW power and around 10m/s moving speed for the focus ...

Viktor