How to make egg crate grille??

dazz · Nov 17, 2017

Hi
I need to make specialised egg crate grille to shade sunlight. It needs to fit to a 10mm pitch which rules out standard grille (12.7mm pitch).
It needs to look something like this:

Which shows part of a 20mm x 10mm grille. The overall dimensions of the grille would be 320mm x 320mm.
In addition the surface needs to absorb incoming light.
Quantity is uncertain but it would be in tens of metres square, not millions.

I have rummaged around the Internet and I think I can buy 20mm and 10mm wide x 0.5mm thick aluminium on a coil.
If I run that between two rollers with many fine Vee-grooves. I can create a light absorbing surface ready for black painting/anodizing.
I could then have a pneumatic cylinder connected to a punch tool to cut the slots at the required pitch along the strip.
The only problem then is assembly of the grille. I think that could be a real pain.

As far as I know, there doesn't seem to be a machine weighing less than 1000kg that would do this job. I am thinking that a custom made machine may be the best option.

Is there a better way???

kb0thn · Nov 17, 2017

Where does the 1000kg constraint come from?

SteveBausch · Nov 17, 2017

Light fixtures?

Milland · Nov 17, 2017

Slotted alumina ceramic fixture plate, assemble sheared pieces, furnace braze.
Injection mold from reasonably high-temp thermoplastic, mold, aluminize or paint.
Longitudinal spars of 10mm height, 20mm pieces laser cut slots, assemble and braze.
Fold crenelated strips, furnace braze or adhesive assembly.

Or, my favorite: Machine from solid, wire EDM voids. Retire.

dazz · Nov 17, 2017

kb0thn said:
Where does the 1000kg constraint come from?

I don't have space for a large heavy machine to do one small job.

dazz · Nov 17, 2017

SteveBausch said:
Light fixtures?

This is for a specialised display but the egg crate grille made for light fixtures is 1/2 inch pitch. No good for my application.

Scottl · Nov 17, 2017

Normally I would suggest assembling slices of square tubing either with adhesive or solder but while 10 x 10 mm outside dimension tubing is readily available in various wall thicknesses you would need something like 9.5 x 9.5 mm with 0.5 mm wall thickness and I know of no such critter.

Do you have a horizontal mill? Gang milling stacks of strips with a slitting saw could create parts that could then be assembled into a grid.

mnl · Nov 17, 2017

If you can use a hexagonal grid you can make a small machine to roll sheet stock into half a hex. The stack and glue them into full hexagons. You can also buy aluminum honeycomb and cut to appropriate length.

SteveBausch · Nov 17, 2017

I’ll check back in a year....

[486] · Nov 17, 2017

Kill the designer, hire a new one that can work with stock components.

Barring that, get a little flywheel punch press and set up for some dies to cut grooves in flat strip at your chosen increments, half the width of the stock, lay it all together and tack each X from the back with a TIG.
Charge out the ass.

sfriedberg · Nov 17, 2017

Just a note about materials, which may or may not be helpful.

The cinema industry uses black matte aluminum foil for masking hot lights. You can buy it in rolls, just like household aluminum foil. Rosco Cinefilm is 0.002" thick (50 micron), and you can get it in 12", 24" and 48" wide rolls from places like FilmTools. (48" wide is probably a special order.) Black matte finish on both sides, and I believe it's done with an epoxy coating, not anodizing, so the foil can be bent without surface cracking. Rosco's not the only maker; Lee also offers this stuff.

If you have the depth, I'd use two layers, one of vertical strips and one of horizontal strips, to build the grill. If you must have both directions in the same layer, you either have to half-slit each direction so they can intersect, or build up a rectangle of zig-zag diagonal strips bonded at their adjacent corners. I have seen cloth eggcrate grills made in both ways. Neither seems especially suited for a 10mm pitch between rows.

EPAIII · Nov 17, 2017

For assembly I think I would make a jig, probably from wood. Glue up a layer of wood that is half the thickness of the finished grill plus about another 15 or 20 mm. Then saw cut slots in it at the 10 mm spacing in both the X and Y directions for half the thickness of the finished grill. Put some end caps on it so the individual slats can only go in it in the proper alignment. Drop the slats for the first direction in it. If there is one set that is only half the full thickness as your picture appears to show, insert those last. Now you can add glue or whatever holds it together to the exposed, upper half of the joints.

A bit of a 45 degree beveled corner (1 mm?) at the opening of each slot will help to assemble them.

If alignment during assembly is too time consuming, you can always make a second layer grid that goes over that first one. It would have it's slots slightly tapered at the top for easy insertion and it would guide the slats down into place.

Greenwud · Nov 17, 2017

dazz said:
Hi
I need to make specialised egg crate grille to shade sunlight. It needs to fit to a 10mm pitch which rules out standard grille (12.7mm pitch).
It needs to look something like this:
View attachment 212987
Which shows part of a 20mm x 10mm grille. The overall dimensions of the grille would be 320mm x 320mm.
In addition the surface needs to absorb incoming light.
Quantity is uncertain but it would be in tens of metres square, not millions.

I have rummaged around the Internet and I think I can buy 20mm and 10mm wide x 0.5mm thick aluminium on a coil.
If I run that between two rollers with many fine Vee-grooves. I can create a light absorbing surface ready for black painting/anodizing.
I could then have a pneumatic cylinder connected to a punch tool to cut the slots at the required pitch along the strip.
The only problem then is assembly of the grille. I think that could be a real pain.

As far as I know, there doesn't seem to be a machine weighing less than 1000kg that would do this job. I am thinking that a custom made machine may be the best option.

Is there a better way???

No natural light at all......?

Have a look at an extrusion catalogue for finely ribbed sections- they are fairly common in some industries.
A jig made of wood will allow slots to be cut at constant pitch and depth using a horizontal mill, radial arm saw or tablesaw. Slot both pieces to interlock.
Braze or tig or epoxy in a jig to hold it all in shape.

dazz · Nov 18, 2017

sfriedberg said:
Just a note about materials, which may or may not be helpful.

The cinema industry uses black matte aluminum foil for masking hot lights. You can buy it in rolls, just like household aluminum foil. Rosco Cinefilm is 0.002" thick (50 micron), and you can get it in 12", 24" and 48" wide rolls from places like FilmTools. (48" wide is probably a special order.) Black matte finish on both sides, and I believe it's done with an epoxy coating, not anodizing, so the foil can be bent without surface cracking. Rosco's not the only maker; Lee also offers this stuff.

If you have the depth, I'd use two layers, one of vertical strips and one of horizontal strips, to build the grill. If you must have both directions in the same layer, you either have to half-slit each direction so they can intersect, or build up a rectangle of zig-zag diagonal strips bonded at their adjacent corners. I have seen cloth eggcrate grills made in both ways. Neither seems especially suited for a 10mm pitch between rows.

This looks promising but foil is too thin, especially for outdoor use. Do you know if coated sheet is available in thicker material?

dazz · Nov 18, 2017

Greenwud said:
No natural light at all......?

I am trying to block direct sunlight.

Milland · Nov 18, 2017

dazz said:
I am trying to block direct sunlight.

If that's the goal, and not specifically having a 10mm pitch, then how about using two sheets of 12.7mm grating one over the other? You can offset them such that you get a functional 6.35 pitch on the apertures, and either black anodize or paint them to absorb incidental light. Or better still, some of the super-fancy light absorbing coatings being developed:

Black Optical Coating, Black Light Absorbing Coatings Material

You may get enough energy absorption with the coatings to expand the grills and bow them in their frames, so this should be planned for by leaving them loose to grow unconstrained.

dazz · Nov 18, 2017

Hi
Carbon nano tubes are interesting and supremely good absorbers but not available locally so I found this website on coating solar absorbtivity and emmitance.

Anodizing or black plastic absorb about 90% incident light which is probably good enough for my application. I want to shield direct sunlight from an LED panel with a 10mm pitch, so pitch is important. Grit blasted black plastic or aluminium should further improve absorbency cheaply.

Milland · Nov 18, 2017

dazz said:
Hi
Carbon nano tubes are interesting and supremely good absorbers but not available locally so I found this website on coating solar absorbtivity and emmitance.

Anodizing or black plastic absorb about 90% incident light which is probably good enough for my application. I want to shield direct sunlight from an LED panel with a 10mm pitch, so pitch is important. Grit blasted black plastic or aluminium should further improve absorbency cheaply.

Well, let me take one more shot at it - if you can use another form-factor, how about a bunch of short lengths of 10mm OD thin wall tubing, with some form of tangency bonding? Super simple, 10mm pitch (assuming good control of the tube OD), and easy to do.

Or, go with a 20mm solid plate, cut slots through half way, drill 9.5mm holes on 10mm centers, bang and done. Should be fairly fast, no worries about joining smaller pieces, should have plenty of aperture for a 10mm LED grid.

dazz · Nov 18, 2017

Milland said:
Well, let me take one more shot at it - if you can use another form-factor, how about a bunch of short lengths of 10mm OD thin wall tubing, with some form of tangency bonding? Super simple, 10mm pitch (assuming good control of the tube OD), and easy to do.

Or, go with a 20mm solid plate, cut slots through half way, drill 9.5mm holes on 10mm centers, bang and done. Should be fairly fast, no worries about joining smaller pieces, should have plenty of aperture for a 10mm LED grid.

I am sure it is a good idea from your point of view and I appreciate your input. You could likely order suitable material over night from a dozen suppliers. I don't have that luxury. I can only source a limited range of "standard" extrusions that don't include thin walled stock. Suitable 20mm plate is also something that would have to be imported on special order ($$$$). I have to work within the limits of a long skinny supply chain.

DDoug · Nov 18, 2017

How to make an egg crate grille ?

First you get yourself some chickens.....

Seriously, your original idea sounds best.

The assembling sounds like a fixture could be made to slightly
bow the ribs to "vee" out the slits for easier insertion.

How to make egg crate grille??

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