Designing a Moveable Support for a Large Mirror

Not my field, but I know we need more information.
Is the mirror already mounted on some form of frame?
What is the mirror made of? Glass presumably as it's so heavy?
How acurate does it's positioning need to be?
What is the purpose of the project?
Move...in what direction? Tilt? Up/down? left/right? fore/aft? rotate?
Move how far? How fast?
I'd suggest building a mock up which moves a 1000..diameter plywood board, that would make a good woodworking project which would provide proof of concept, it would also be cheap, quick, simple and would teach you where the problems lie.
Unless you have a good CAD system and the expertise to use it, but even then, I'd say have a play first to get a feel for the magnitude of the problem.
Del

The mirror is made from a specialized piece of metal. It is round and there is no mounting on the mirror itself. There can be no mount on the mirror as well. It is moving up/down The structure is abt 2m height from ground to the ctr of the mirror. I was thinking of making supports on the sides and below the mirror by fabricating a block with a groove to support the mirror. The speed of movement will be better if it slow just for safety purposes if you ask me.

Don't you feel the mirror is too thick ? (steel: it must be about 72mm thick : for a mirror)

Provide some type of linear rail on both the vertical supports so the mirror holder has up and down movement. Place pulley top of each vertical support and use a line and a counter balance to hold it in position. You may want to provide an enclosure for the counter balance to move up and down in to keep it from swinging. Maybe even build the vertical supports so it hangs inside.

Try attaching 4'x8' sheet of plwood to a drywall jack ,it can be tilted and can be spun to differrent dirrections, then attach giant mirror to that. check the weight factor of drywall jack to handle weight load. It has wheels on it to roll around. You can rent at some hardware stores.

I would mock up in wood, then build in box section mild steel.

For moving accurately I would use threaded rods (thick ones at least 1" thick), driven by large stepper motors ( if the threaded rod part is effectively made as a gear down system, if high speed moving is not a requirement, then the motors need not be so large), using a PC with Linux (Ubuntu) and EMC2 from Sourceforge, a free stepper motor control system from Sourceforge that can drive up to 7 axis (if I remember correctly!).

Make sure that the threaded rods have both radial and axial bearings at both ends (there are expensive bearings that can do both, but using both radial and axial bearings separately will cut costs dramatically), make sure you buy the radial bearings with dust covers built in, and use a plastic cap from spray cans or similar to keep dust out of the axial bearings......

Oversize everything to give it a long and accurate life.....especially the bearings on which the mirror itself is mounted.

On www.CNCZone.com (amongst others) you can find free schematics or even finished driver boards and a simple (parallel printer port) interface to allow the stepper motors to be driven accurately......

The whole system could be easily self built!! each part given to a different department in the school to finish!! It should be great fun for all concerned.

By the way, if you buy stepper motors that need between 2.5 - 3 amps, there are many chips around that make the job much easier....

This should allow the mirror to be driven not just at ° Degree accuracy, but at Minute accuracy (1/60th of a degree!!!) or better......

If you need further tips (assuming you go in this direction!) just ask.

Tell us, djcool:

This project... is there a financial budget you are to stay within? Is there a time budget you are to stay within? Do you have access to school woodshop or metal shop? Are some of the team members accomplished wood or metal workers? Or, are you simply to design a theoretical apparatus? If this is the case, does it have to work?

This mirror... some sort of polished metal, 450kg? Has this mirror already been delivered to school? (Perhaps fabricated in school metalshop; THAT would have been a fun project)

No financial budget...yet atleast.. Yes i do have a metal workshop. Yes it does have to work. For now they want a drawing/ design. After design.. the fabrication will be done at a metal workshop and yes it has to work...

My initial suggestions:

To use an I-Beam 150 x 100 x 10mm(thickness) for the sides for strong support. The pulley system or a rack and pineon system to be used on the beams. Just cracking my head on how to support the heavy mirror and what type of calculations do i need.

(me and my big mouth... volunteering for this project)

Sounds like you have been/will be stitched up.
Get a specification in writing, else when it's finished some git will say 'Oh doesn't it pivot then?'

Mind even with a specification you will get 'Wouldn't it be nice if it....tilted/panned/was painted blue etc'

But at leat you can hold the spec' over your head and run for cover....
Del

TV cameras us a sealed hydraulic system on a arm .this yous es the weight of the camera against its self only a small counter balance required.you should be able to find more info on line.