5 ms·

Manufacturing next-generation electronics like they are T-Shirts

67 points by SG16 5y ago

digikata 5y ago
Pcb manufacture has long used screen printing techniques to apply solder paste and label stencils. The new part here is using it to apply things like conductive ink traces. I would think there are different electrical characteristics to account for - as the article alludes to, but also strength of bond to the substrate (esp for components like connectors).
- madengr 5y ago
  LTCC has used screen printing of conductive pastes for decades. https://en.m.wikipedia.org/wiki/Co-fired_ceramic https://en.m.wikipedia.org/wiki/Co-fired_ceramic
- SG16 5y ago
  The adhesive strength of inks to the substrate is measured with two tests: a tape test with 3M Scotch 234 and the conventional cross cut test. Usually, the change in electrical resistance is taken into account while performing these tests. For high frequency or radio applications, the surface roughness of the dry film is important.
monkmartinez 5y ago
This is soooo cool, but getting a PCB made is super easy and cheap right now (chip shortages, notwithstanding). How will these types of circuits handle higher voltages and currents? Will that be simply a case of printing on the right substrate?
- swalsh 5y ago
  How easy will it be to get a PCB made if relations with China keep deteriating? The US has PCB manufacturers, but they are WAY more expensive.
  - jagger27 5y ago
    China isn't the only game in town. India and other SEA countries could pick up some of the demand, alongside domestic producers.
  - conk 5y ago
    Cost of production in Canada or Mexico is close enough to Asian suppliers with the benefit of shorter lead times, less language barrier and similarly time zones.
  - mhh__ 5y ago
    That probably depends on whether you are a hobbyist who needs it on the cheap, a small business who can charge a premium for excellence, or a big company that needs their margins.
- Animats 5y ago
  The do it yourself process shown just makes one-sided boards with no holes. If you want two-sided boards, you need precision fixtures so that the sides line up. Then there's drilling and through-hole plating. Some hobbyists uses rivets instead of plated through holes, but that's a pain and the rivets take up a lot of board space. As a production process it has some uses, but mainly for larger, more flexible stuff. LED clothing, maybe?
  - bigiain 5y ago
    I wonder if you could pre drill the holes, and just squirt a bunch of ink into them to make a via?
    - Animats 5y ago
      That's an interesting idea. It was tried in 2015 as a DIY process.[1] They had a little CNC drilling rig, and they'd use it for both drilling and ink depositing. Don't know if anyone picked up on that. Might not work if you put component pins through via holes. Plated through holes have enough hard metal to withstand that. Conductive ink, maybe not. As usual, making your own boards is more trouble than it's worth. Board making services are cheap and all the DIY processes produce an inferior product to even low-end board services. [1] https://youtu.be/oJyoXwNONho https://youtu.be/oJyoXwNONho
vsskanth 5y ago
I wonder if someone has figured out how to use inkjet or screen printing to make a simple wifi/bluetooth transmitter or an NFC tag. So far I've only seen the antennas printable but not the transistor logic.
- parsecs 5y ago
  I don't think inkjet printers have anywhere near enough resolution to get WiFi/BT or even NFC tags - those things are incredibly complicated. I expect it would also take a whole bunch of engineering to get the printed ink perform well at such high frequencies
  - nl 5y ago
    Thus article talks about screenprinting RFID (=NFC) tags. I'd be surprised if an inkjet can't get higher resolution than screenprinting. Doesn't solve the transistor issue the OP was asking about though.
  - alted 5y ago
    A WiFi/BT/NFC tag system has an antenna, and a radio circuit attached to the antenna. It's almost possible to inkjet print circuitry with transistors in research applications; see [1]. 20 micrometer resolution is relatively easy, so a WiFi/BT or NFC antenna (~millimeter scale) is very possible. I agree, the tricky bit is making (a) enough transistors to for the radio at (b) sufficiently high frequencies. As in [1], inkjet-printed transistor circuits have at most ~10 transistors as of yet (and NFC chips, with > 512 bit memory, need at least hundreds if not thousands). According to [2], inkjet printed organic transistors are in the range of MHz frequencies; NFC (~13 MHz) may be possible; WiFi (~2.2 GHz) may not be for a while yet. [1] https://news.ycombinator.com/item?id=24129506 https://news.ycombinator.com/item?id=24129506 [2] https://doi.org/10.1021/acsnano.6b06041 https://doi.org/10.1021/acsnano.6b06041
- digikata 5y ago
  It would be neat if you could print in some of the jellybean components - even just covering a range of resistors would be interesting.
blueblisters 5y ago
I don’t think screen printing works very well for features below 50 microns. And it’s tricky to control the thickness of deposition too. There are several other printing methods that are faster and more precise - like roll-to-roll gravure, flexo or offset printing. There’s a lot of innovation happening in this space to get very small features printed extremely fast.
baybal2 5y ago
Imho, the author had n poor idea how electronics is actually manufactured
cardamomo 5y ago
From the title, I assumed this would be about knitting the electronics. It's actually about screen printing. I'm sure I'll come back in a few years and find an article about knitting a circuit board, though.

67 points by SG16 5y ago

Pcb manufacture has long used screen printing techniques to apply solder paste and label stencils. The new part here is using it to apply things like conductive ink traces. I would think there are different electrical characteristics to account for - as the article alludes to, but also strength of bond to the substrate (esp for components like connectors).

madengr 5y ago
LTCC has used screen printing of conductive pastes for decades. https://en.m.wikipedia.org/wiki/Co-fired_ceramic https://en.m.wikipedia.org/wiki/Co-fired_ceramic
SG16 5y ago
The adhesive strength of inks to the substrate is measured with two tests: a tape test with 3M Scotch 234 and the conventional cross cut test. Usually, the change in electrical resistance is taken into account while performing these tests. For high frequency or radio applications, the surface roughness of the dry film is important.

monkmartinez 5y ago

This is soooo cool, but getting a PCB made is super easy and cheap right now (chip shortages, notwithstanding). How will these types of circuits handle higher voltages and currents? Will that be simply a case of printing on the right substrate?

swalsh 5y ago
How easy will it be to get a PCB made if relations with China keep deteriating? The US has PCB manufacturers, but they are WAY more expensive.
- jagger27 5y ago
  China isn't the only game in town. India and other SEA countries could pick up some of the demand, alongside domestic producers.
- conk 5y ago
  Cost of production in Canada or Mexico is close enough to Asian suppliers with the benefit of shorter lead times, less language barrier and similarly time zones.
- mhh__ 5y ago
  That probably depends on whether you are a hobbyist who needs it on the cheap, a small business who can charge a premium for excellence, or a big company that needs their margins.
Animats 5y ago
The do it yourself process shown just makes one-sided boards with no holes. If you want two-sided boards, you need precision fixtures so that the sides line up. Then there's drilling and through-hole plating. Some hobbyists uses rivets instead of plated through holes, but that's a pain and the rivets take up a lot of board space. As a production process it has some uses, but mainly for larger, more flexible stuff. LED clothing, maybe?
- bigiain 5y ago
  I wonder if you could pre drill the holes, and just squirt a bunch of ink into them to make a via?
  - Animats 5y ago
    That's an interesting idea. It was tried in 2015 as a DIY process.[1] They had a little CNC drilling rig, and they'd use it for both drilling and ink depositing. Don't know if anyone picked up on that. Might not work if you put component pins through via holes. Plated through holes have enough hard metal to withstand that. Conductive ink, maybe not. As usual, making your own boards is more trouble than it's worth. Board making services are cheap and all the DIY processes produce an inferior product to even low-end board services. [1] https://youtu.be/oJyoXwNONho https://youtu.be/oJyoXwNONho

vsskanth 5y ago

I wonder if someone has figured out how to use inkjet or screen printing to make a simple wifi/bluetooth transmitter or an NFC tag. So far I've only seen the antennas printable but not the transistor logic.

parsecs 5y ago
I don't think inkjet printers have anywhere near enough resolution to get WiFi/BT or even NFC tags - those things are incredibly complicated. I expect it would also take a whole bunch of engineering to get the printed ink perform well at such high frequencies
- nl 5y ago
  Thus article talks about screenprinting RFID (=NFC) tags. I'd be surprised if an inkjet can't get higher resolution than screenprinting. Doesn't solve the transistor issue the OP was asking about though.
- alted 5y ago
  A WiFi/BT/NFC tag system has an antenna, and a radio circuit attached to the antenna. It's almost possible to inkjet print circuitry with transistors in research applications; see [1]. 20 micrometer resolution is relatively easy, so a WiFi/BT or NFC antenna (~millimeter scale) is very possible. I agree, the tricky bit is making (a) enough transistors to for the radio at (b) sufficiently high frequencies. As in [1], inkjet-printed transistor circuits have at most ~10 transistors as of yet (and NFC chips, with > 512 bit memory, need at least hundreds if not thousands). According to [2], inkjet printed organic transistors are in the range of MHz frequencies; NFC (~13 MHz) may be possible; WiFi (~2.2 GHz) may not be for a while yet. [1] https://news.ycombinator.com/item?id=24129506 https://news.ycombinator.com/item?id=24129506 [2] https://doi.org/10.1021/acsnano.6b06041 https://doi.org/10.1021/acsnano.6b06041
digikata 5y ago
It would be neat if you could print in some of the jellybean components - even just covering a range of resistors would be interesting.

blueblisters 5y ago

I don’t think screen printing works very well for features below 50 microns. And it’s tricky to control the thickness of deposition too. There are several other printing methods that are faster and more precise - like roll-to-roll gravure, flexo or offset printing. There’s a lot of innovation happening in this space to get very small features printed extremely fast.

baybal2 5y ago

Imho, the author had n poor idea how electronics is actually manufactured

cardamomo 5y ago

From the title, I assumed this would be about knitting the electronics. It's actually about screen printing. I'm sure I'll come back in a few years and find an article about knitting a circuit board, though.