Hi there!
I'm trying to build a planar speaker and ideally I want to use super super super dense tracing (0.0762mm trace width, 0.0762 mm spacing).
I can do this with flexible PCBs but the diaphrams they offer are not thin enough.
How do companies do this sort of thing? How do you professionally cut ultra thin alluminum and apply it to mylar?
I can etch my own alluminum and possibly attach it myself but how do I cut it?
I'm willing to spend some money on some special equipment if needed but I don't know what that equipment may be.
Would appreciate any ideas thrown at me 🙂
I'm trying to build a planar speaker and ideally I want to use super super super dense tracing (0.0762mm trace width, 0.0762 mm spacing).
I can do this with flexible PCBs but the diaphrams they offer are not thin enough.
How do companies do this sort of thing? How do you professionally cut ultra thin alluminum and apply it to mylar?
I can etch my own alluminum and possibly attach it myself but how do I cut it?
I'm willing to spend some money on some special equipment if needed but I don't know what that equipment may be.
Would appreciate any ideas thrown at me 🙂
The metallized film is commonly used in food packaging.
It is usually coated to prevent the aluminum from corrosion.
So you will have to find somebody who will sell you this film from before the coating stage.
And you will have to use a chemical which attacks aluminum but leaves the plastic unharmed....
Another use is rescue thermal blankets.
Search for suppliers conveniently located.
It is cheap, buy too much to experiment with.
Removing film is easier than applying a coat, in my opinion.
It is usually coated to prevent the aluminum from corrosion.
So you will have to find somebody who will sell you this film from before the coating stage.
And you will have to use a chemical which attacks aluminum but leaves the plastic unharmed....
Another use is rescue thermal blankets.
Search for suppliers conveniently located.
It is cheap, buy too much to experiment with.
Removing film is easier than applying a coat, in my opinion.
Do anyone know of such a chemical?
I wonder if NaOH will eat mylar..
Food packaging and thermal blankets have a significantly different ratio and amount of mylar/alluminum then what would be required though. So I would need to find someone willing to do a custom job.
I wonder if NaOH will eat mylar..
Food packaging and thermal blankets have a significantly different ratio and amount of mylar/alluminum then what would be required though. So I would need to find someone willing to do a custom job.
A custom job would be expensive, ask around in your country.
And search for similar films in scientific supply stores.
There are threads on this topic too, I think.
Screen printing conductive carbon ink might work?
Another thought, how are LED strips made?
They are made of SMD LEDs soldered to a flexible substrate.
Might find some clues there.
And search for similar films in scientific supply stores.
There are threads on this topic too, I think.
Screen printing conductive carbon ink might work?
Another thought, how are LED strips made?
They are made of SMD LEDs soldered to a flexible substrate.
Might find some clues there.
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I think the issue with those things is the thickness.
I'm looking for aluminum thickness of a few microns and even less for the mylar.
I think the chemical etching was a good idea, but sourcing the correct metallized mylar could be an issue based on what I know about that industry.
I could etch the foil down and use the super-77glue method to attach to mylar but I question how well the glue would hold up in a chemical bath.
The preferred option is to use vacuum deposition onto mylar but I wouldn't know where to begin to find a service for that.
I'm looking for aluminum thickness of a few microns and even less for the mylar.
I think the chemical etching was a good idea, but sourcing the correct metallized mylar could be an issue based on what I know about that industry.
I could etch the foil down and use the super-77glue method to attach to mylar but I question how well the glue would hold up in a chemical bath.
The preferred option is to use vacuum deposition onto mylar but I wouldn't know where to begin to find a service for that.
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Food film is made by vacuum metal deposition, the thicknesses should meet your needs.
Look at film suppliers' sites.
Look at film suppliers' sites.
The old Maggies were actually wires glued to the membrane.
I would assume, modern planers or AMs are done by etching.
I would assume, modern planers or AMs are done by etching.
I did inquire some vacuum deposition facilities in the past but they did not allow for the size or thicknesses that I wanted.
Typically food film manufacturers only allow super thin layers of aluminum (much less than a few microns) on fairly thick layers of mylar which is also not what I want.
So to my knowledge, conventional manufacturing processes won't fit the bill. Correct me if I am wrong.
Etching seems to be a good temporary solution as long as I can figure out if the mylar and glue can survive a chemical bath and if I can find a way to print a 'negative' cover for the aluminum with 3 mil tolerances.
Typically food film manufacturers only allow super thin layers of aluminum (much less than a few microns) on fairly thick layers of mylar which is also not what I want.
So to my knowledge, conventional manufacturing processes won't fit the bill. Correct me if I am wrong.
Etching seems to be a good temporary solution as long as I can figure out if the mylar and glue can survive a chemical bath and if I can find a way to print a 'negative' cover for the aluminum with 3 mil tolerances.
Interesting! I have not heard of that method before. I usually use NaOH.
Do you know how those two compare?
I am afraid I don’t understand what you are trying to do.
In a normal electrostatic loudspeaker there are two electrodes, one on each side of the diaphragm. They can be simple wire forming a grid, metal screening or even punched metal.
Stretched between the electrodes is a thin Mylar film. A .0005” film may be purchased from
http://k-mac-plastics.com/mylar-sheet.htm
To make this conductive you can rub it with graphite powder or more popular today would be a mildly conductive “anti-static” spray. “Scotchgard” comes to mind.
In the past there was an issue with some very sensitive D’Arsonval meters. I just cleaned the plastic case with liquid dishwashing soap. This left a fine conductive film on the meter and solved the problem.
As to etching with ferric chloride, it vigorously attacks aluminum. Pretty much nothing will etch Mylar.
In a normal electrostatic loudspeaker there are two electrodes, one on each side of the diaphragm. They can be simple wire forming a grid, metal screening or even punched metal.
Stretched between the electrodes is a thin Mylar film. A .0005” film may be purchased from
http://k-mac-plastics.com/mylar-sheet.htm
To make this conductive you can rub it with graphite powder or more popular today would be a mildly conductive “anti-static” spray. “Scotchgard” comes to mind.
In the past there was an issue with some very sensitive D’Arsonval meters. I just cleaned the plastic case with liquid dishwashing soap. This left a fine conductive film on the meter and solved the problem.
As to etching with ferric chloride, it vigorously attacks aluminum. Pretty much nothing will etch Mylar.
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I don't believe I ever mentioned electrostatic speakers dear sir. This is for a planar speaker.
Thanks for the information though 🙂
Thanks for the information though 🙂
Is there a good way for me to apply a fine negative ink print to the aluminum for etching with FeCl? A typical mechanical printer of any sort will destroy the aluminum at this thickness.
Then try a film like
https://www.mcmaster.com/aluminized-film/
Try using a sprayable photo emulsion intended for printed circuits.
https://www.microchemicals.com/products/photoresists/pr_cir_board_resist.html
https://mungolux.com/Liquid-Photoresist
Then etch with ferric chloride.
https://www.mcmaster.com/aluminized-film/
Try using a sprayable photo emulsion intended for printed circuits.
https://www.microchemicals.com/products/photoresists/pr_cir_board_resist.html
https://mungolux.com/Liquid-Photoresist
Then etch with ferric chloride.
If you don't want to do a photo etch directly on the film, you could make a silkscreen with your pattern (which is also a photo etch process, but on the screen), then you effectively print your resist pattern on the mylar and etch. you can use the silkscreen over and over again.
I bought about 400lbs of metalized mylar (1/2 mil) for a work project. It's like $4 a pound, which is like a quarter mile. You want to look for "converters" which take big rolls (think 400lbs +) and slit them to width and wind them on smaller cores. In the new england area, we used a place called "Flagship Converters"
Sheldon
I bought about 400lbs of metalized mylar (1/2 mil) for a work project. It's like $4 a pound, which is like a quarter mile. You want to look for "converters" which take big rolls (think 400lbs +) and slit them to width and wind them on smaller cores. In the new england area, we used a place called "Flagship Converters"
Sheldon
The practical aspect of silk screening on thin film,possibly held taut on a frame has to be thought about.
Then it has to be processed, and finally mounted.
A printing shop might have some ideas.
And how will you attach the conductors in a durable way to the grid?
Then it has to be processed, and finally mounted.
A printing shop might have some ideas.
And how will you attach the conductors in a durable way to the grid?
Way too thick unfortunately
That could work but I would need to order a piece of plastic or something with the pattern to stencil the pattern on to the aluminum because the traces will be 3 mil or less.
Do you mean to etch the pattern into the silkscreen and then to use the silkscreen as a stencil for the ink? Hmmm. That could work.
Do you think those metalized mylar rolls for "converters" will go down to 0.1 mil? I'm looking for 0.5 micron mylar. What is a "converter" in this context by the way?