Optical breadboard thickness - how much is really needed?

[Stuka]

I had a question concerning the recommended thickness of an optical breadboard for my first RGB projector. I plan on building a split-level design, with the optics and laser heads mounted to the breadboard on the "upper level". The breadboard would be supported on two opposing ends by brackets attached to the enclosure. Breadboard dimensions will probably be 12" x 18".

Would a 1/4" breadboard be thick enough for this type of projector design? This projector will primarily be for home hobby use, so I don't anticipate a lot of travel-induced wear & tear for this one.

Thanks!

Randy

[Laser Ben]

I would say at least 0.375-0.75 for something that large. Especially if it is a RGb with all the alignment.

[buffo]

Without some longitudinal bracing, you're probably going to get a little flex in that breadboard, especially if you drill it full of holes. My breadboard is only 9 inches by 14 inches (it's 1/4 inch thick), and I've got two longitudinal braces that are about 2 inches wide (and also 1/4 inch thick) that support it underneath. Then too, I've also got the floating tables for all the lasers (suspended above the main table w/ #10 threaded rod), so that adds to the rigidity of the unit.

My setup doesn't flex at all, but it's well supported. I think if you support your table like I did, you'll be fine. But only supporting it at the edges is asking for trouble, in my opinion.

Adam

[CDBEAM]

I am also in the stage of assembling the platforms for a "double-decker" design...with plate dimensions of 14.5" x 12.5" x .25". Upper and lower deck to be attached by (4) four 9" long by 3/8" dia SS rod stock with bolt elevation adjustment. The plan is to space the rod stock " pillars" well inside the outer footprint perimeter....based upon laser head/optics/electronics arrangment. So....the pillars will end up around 2~2.5" in from the edge. I am hopefull that this geometry will NOT require additional stiffeners to limit flex. Also planned is the eventual addition of an outer skin which will be screw attached to both the upper and lower elevations. Note: platform material is 303 Aluminium plate stock.Comments??? suggestions ??? Thanx...Bob

[Laser Ben]

It might be worth it to add 1" wide strips of 0.5" Aluminum along the sides of the optical table. That would ensure no flexing and give you another place to attach the case.

[buffo]

I agree with Ben. I'd add some stiffening to that design Bob. Either the bracing around the edge or some sort of longitudinal brace should work.

If you do get some flex, it's not the end of the world. It just means that you'll have to re-align the projector after you move it... The alignment won't be very far off, so we're only talking about a minute or two of tweaking. Still, if you can avoid that, you'll be happier.

Adam

[mixedgas]

[QUOTE=Buffo;31865]I agree with Ben. I'd add some stiffening to that design Bob. Either the bracing around the edge or some sort of longitudinal brace should work.


for non braced plates up to 14 x14", I just go with .5" 6061 AL

for anything bigger, like a long table, my standard is .25 (1/4") AL 6061
12" wide by however long I need with two 1x1" AL stringers bolted along lengthwise to the plate with a countersinked screw every 4 inches. This has similar stiffness to a baseline commecial optical table. If you go wider then 1 foot, add a stiffener every 6". A cross section looks like this []_______[] (drawn upside down)

I also use slotted Al extrusion for the box framing to add strength and damping. A short height frame of 1" extrusion adds damping if its less then say 8" tall and the slots in the extrusion are .250 wide, perfect for holding standard lexan and acrylic panels , which are .220 as standard.

The commercial laser wizardry road projectors are built with 3/8s baseplate, 1x1" solid stringers, and 1/8th thick angle stock for the corners, with 1/8" thick AL side plates, but you need a forklift to move em. I think Prometheus two weights in at 1oo pounds.

I get my cheapest slotted extrusion here:
They cal it Tslot tubing. It has other names like Parker Parframe (tm)

www.automation4less.com


I buy the solid corner cubes from Thorlabs though, cheaper and better.

PS, since the panels can be held captive with the Tslot stuff, it makes variancing easier.

Steve Roberts

[steve-o]

Hey Steve,
Glad to see you're still around after playing with the 'arc-lamp' - or was it boring? (you did get it -right?)
-Steve

[CDBEAM]

Thanx guy for your imput...It is really good to benifit from your experiense !!!!!! I will modify accordingly!!!and also...it is very
difficult to edge drill the 1/4" Aluminum plates for future case
exterior...THAT brillant idea has been dropped !!! Thanx, Bob

[mixedgas]

Hey Steve,
Glad to see you're still around after playing with the 'arc-lamp' - or was it boring? (you did get it -right?)
-Steve

Oh we have plans for that
like "arcing around the christmas tree, its a happy happy day....."
Seriously thinking about adding some carbon and some feed :-)
Probably a solenoid for kickstarting.......


Did you get amps working yet for the g124s?

Steve