In-house flexible PCB production

Guest
We currently use 'Mega 400-105'
(https://www.megauk.com/downloads/mega_catalogue.pdf) board material
which is a UV resist type with a 50um thick Polyester substrate but it
has been discontinued and we may also be loosing our darkroom at some
stage.

Could anyone recommend a PCB milling or other machine and a flexible
type board material it can use? This will be for small board sizes,
small volume / prototyping work.

The conductor material needs to be copper as the boards will be used for
low temperature physics work. eg. PCB printing machines which use a
silver-based ink won't do.

Thanks
Tom Crane

Ps. The email address in the header is just a spam-trap.
--
Tom Crane, Dept. Physics, Royal Holloway, University of London, Egham Hill,
Egham, Surrey, TW20 0EX, England.
Email: T dot Crane at rhul dot ac dot uk
 
On Thursday, May 16, 2019 at 10:02:11 AM UTC-4, Use-Author-Suppli...@127.1 wrote:
We currently use 'Mega 400-105'
(https://www.megauk.com/downloads/mega_catalogue.pdf) board material
which is a UV resist type with a 50um thick Polyester substrate but it
has been discontinued and we may also be loosing our darkroom at some
stage.
Click to expand...

Can you buy a life time supply?

Can you tell us why regular fiberglass pcb's won't work?

I once had this idea of using long thin pcb's to carry signals
down into LN2 dewars.. sorta both structural and with wires.
But I never tried it.

George H.
Could anyone recommend a PCB milling or other machine and a flexible
type board material it can use? This will be for small board sizes,
small volume / prototyping work.

The conductor material needs to be copper as the boards will be used for
low temperature physics work. eg. PCB printing machines which use a
silver-based ink won't do.

Thanks
Tom Crane

Ps. The email address in the header is just a spam-trap.
--
Tom Crane, Dept. Physics, Royal Holloway, University of London, Egham Hill,
Egham, Surrey, TW20 0EX, England.
Email: T dot Crane at rhul dot ac dot uk
Click to expand...
 
George Herold <gherold@teachspin.com> wrote:
: On Thursday, May 16, 2019 at 10:02:11 AM UTC-4, Use-Author-Suppli...@127.1 wrote:
: > We currently use 'Mega 400-105'
: > (https://www.megauk.com/downloads/mega_catalogue.pdf) board material
: > which is a UV resist type with a 50um thick Polyester substrate but it
: > has been discontinued and we may also be loosing our darkroom at some
: > stage.

: Can you buy a life time supply?
I could not find anywhere that still has stocks. Amazon & CPC/Farnell
both list it but indicate "Currently unavailable" and "No Longer
Manufactured". Mega's FAQ confirms this and explains why.

: Can you tell us why regular fiberglass pcb's won't work?
I think the attraction is that being thin it fits easily into confined
spaces and can be varnished onto curved surfaces such as cryostat
pumping lines.

: I once had this idea of using long thin pcb's to carry signals
: down into LN2 dewars.. sorta both structural and with wires.
: But I never tried it.

My colleagues tend to use the conventional approach -- enamelled copper
wires varnished onto cryostat pumping lines, dilution fridge parts
(eg. mixing chambers). The small flexible PCBs make convenient
tag-strips / joiners or as a means to insert SM resistors etc.

Tom.

: George H.
: >
: > Could anyone recommend a PCB milling or other machine and a flexible
: > type board material it can use? This will be for small board sizes,
: > small volume / prototyping work.
: >
: > The conductor material needs to be copper as the boards will be used for
: > low temperature physics work. eg. PCB printing machines which use a
: > silver-based ink won't do.
: >
: > Thanks
: > Tom Crane
: >
: > Ps. The email address in the header is just a spam-trap.
: > --
: > Tom Crane, Dept. Physics, Royal Holloway, University of London, Egham Hill,
: > Egham, Surrey, TW20 0EX, England.
: > Email: T dot Crane at rhul dot ac dot uk


--
Ps. The email address in the header is just a spam-trap.

Tom Crane, Dept. Physics, Royal Holloway, University of London, Egham Hill,
Egham, Surrey, TW20 0EX, England.
Email: T dot Crane at rhul dot ac dot uk
 
On Friday, May 17, 2019 at 12:02:12 PM UTC-4, Use-Author-Suppli...@127.1 wrote:
George Herold <gherold@teachspin.com> wrote:
: On Thursday, May 16, 2019 at 10:02:11 AM UTC-4, Use-Author-Suppli...@127.1 wrote:
: > We currently use 'Mega 400-105'
: > (https://www.megauk.com/downloads/mega_catalogue.pdf) board material
: > which is a UV resist type with a 50um thick Polyester substrate but it
: > has been discontinued and we may also be loosing our darkroom at some
: > stage.

: Can you buy a life time supply?
I could not find anywhere that still has stocks. Amazon & CPC/Farnell
both list it but indicate "Currently unavailable" and "No Longer
Manufactured". Mega's FAQ confirms this and explains why.

: Can you tell us why regular fiberglass pcb's won't work?
I think the attraction is that being thin it fits easily into confined
spaces and can be varnished onto curved surfaces such as cryostat
pumping lines.
Click to expand...

Good enough. I once had similar thoughts and went looking for a board
house that would make proto-type quantities of copper on flex...
Too spendy.

Searching for DIY flex pcb I get a bunch of hits.
how about this,
https://www.adafruit.com/product/1894

Searching for Pyralux I find more.

Is there something wrong with kapton/ polyimide? And how do you stick it
to your pumping lines?

George H.
: I once had this idea of using long thin pcb's to carry signals
: down into LN2 dewars.. sorta both structural and with wires.
: But I never tried it.

My colleagues tend to use the conventional approach -- enamelled copper
wires varnished onto cryostat pumping lines, dilution fridge parts
(eg. mixing chambers). The small flexible PCBs make convenient
tag-strips / joiners or as a means to insert SM resistors etc.

Tom.

: George H.
:
: > Could anyone recommend a PCB milling or other machine and a flexible
: > type board material it can use? This will be for small board sizes,
: > small volume / prototyping work.
:
: > The conductor material needs to be copper as the boards will be used for
: > low temperature physics work. eg. PCB printing machines which use a
: > silver-based ink won't do.
:
: > Thanks
: > Tom Crane
:
: > Ps. The email address in the header is just a spam-trap.
: > --
: > Tom Crane, Dept. Physics, Royal Holloway, University of London, Egham Hill,
: > Egham, Surrey, TW20 0EX, England.
: > Email: T dot Crane at rhul dot ac dot uk


--
Ps. The email address in the header is just a spam-trap.

Tom Crane, Dept. Physics, Royal Holloway, University of London, Egham Hill,
Egham, Surrey, TW20 0EX, England.
Email: T dot Crane at rhul dot ac dot uk
Click to expand...
 
George Herold <gherold@teachspin.com> wrote:
: On Friday, May 17, 2019 at 12:02:12 PM UTC-4, Use-Author-Suppli...@127.1 wrote:
: > George Herold <gherold@teachspin.com> wrote:
: > : On Thursday, May 16, 2019 at 10:02:11 AM UTC-4, Use-Author-Suppli...@127.1 wrote:
: > : > We currently use 'Mega 400-105'
: > : > (https://www.megauk.com/downloads/mega_catalogue.pdf) board material
: > : > which is a UV resist type with a 50um thick Polyester substrate but it
: > : > has been discontinued and we may also be loosing our darkroom at some
: > : > stage.
: >
: > : Can you buy a life time supply?
: > I could not find anywhere that still has stocks. Amazon & CPC/Farnell
: > both list it but indicate "Currently unavailable" and "No Longer
: > Manufactured". Mega's FAQ confirms this and explains why.
: >
: > : Can you tell us why regular fiberglass pcb's won't work?
: > I think the attraction is that being thin it fits easily into confined
: > spaces and can be varnished onto curved surfaces such as cryostat
: > pumping lines.

: Good enough. I once had similar thoughts and went looking for a board
: house that would make proto-type quantities of copper on flex...
: Too spendy.

Doing some web browsing on milling machines suggests some are capable
of handling 50um or thinner substrates, including the Othermill brand
(now Bantam Tools) and Accurate CNCs. I'm guessing the mechanical
mills will be significantly cheaper than the laser ones. None of the
manufacturers or distributors websites I looked at included prices which
is probably an indication of their height!

: Searching for DIY flex pcb I get a bunch of hits.
: how about this,
: https://www.adafruit.com/product/1894

: Searching for Pyralux I find more.

Thanks for those pointers. The Pyralux looks interesting as does the
AN10 and AN210 thin/flex FR4 board from CIF.

: Is there something wrong with kapton/ polyimide?

No. People here use Kapton tape in cryostats for its wide temperature
range stability.

: And how do you stick it
: to your pumping lines?

I have not been involved in actually doing Low Temperature work myself
for many years now but I believe the usual technique is GE varnish.

: George H.

Tom.

Ps. I've just noticed your email domain. We have one of your earth field NMR spectrometers here!

Pps. The email address in the header is just a spam-trap.
--
Tom Crane, Dept. Physics, Royal Holloway, University of London, Egham Hill,
Egham, Surrey, TW20 0EX, England.
Email: T dot Crane at rhul dot ac dot uk
 
On Tuesday, May 21, 2019 at 9:50:00 PM UTC-4, Use-Author-Suppli...@127.1 wrote:
George Herold <gherold@teachspin.com> wrote:
: On Friday, May 17, 2019 at 12:02:12 PM UTC-4, Use-Author-Suppli...@127.1 wrote:
: > George Herold <gherold@teachspin.com> wrote:
: > : On Thursday, May 16, 2019 at 10:02:11 AM UTC-4, Use-Author-Suppli...@127.1 wrote:
: > : > We currently use 'Mega 400-105'
: > : > (https://www.megauk.com/downloads/mega_catalogue.pdf) board material
: > : > which is a UV resist type with a 50um thick Polyester substrate but it
: > : > has been discontinued and we may also be loosing our darkroom at some
: > : > stage.
:
: > : Can you buy a life time supply?
: > I could not find anywhere that still has stocks. Amazon & CPC/Farnell
: > both list it but indicate "Currently unavailable" and "No Longer
: > Manufactured". Mega's FAQ confirms this and explains why.
:
: > : Can you tell us why regular fiberglass pcb's won't work?
: > I think the attraction is that being thin it fits easily into confined
: > spaces and can be varnished onto curved surfaces such as cryostat
: > pumping lines.

: Good enough. I once had similar thoughts and went looking for a board
: house that would make proto-type quantities of copper on flex...
: Too spendy.

Doing some web browsing on milling machines suggests some are capable
of handling 50um or thinner substrates, including the Othermill brand
(now Bantam Tools) and Accurate CNCs. I'm guessing the mechanical
mills will be significantly cheaper than the laser ones. None of the
manufacturers or distributors websites I looked at included prices which
is probably an indication of their height!

: Searching for DIY flex pcb I get a bunch of hits.
: how about this,
: https://www.adafruit.com/product/1894

: Searching for Pyralux I find more.

Thanks for those pointers. The Pyralux looks interesting as does the
AN10 and AN210 thin/flex FR4 board from CIF.

: Is there something wrong with kapton/ polyimide?

No. People here use Kapton tape in cryostats for its wide temperature
range stability.

: And how do you stick it
: to your pumping lines?

I have not been involved in actually doing Low Temperature work myself
for many years now but I believe the usual technique is GE varnish.
OK thanks, I used GE varnish years ago...

: George H.

Tom.

Ps. I've just noticed your email domain. We have one of your earth field NMR spectrometers here!
That's a fun piece of apparatus. Magnetic field gradients can be a real issue.
Click to expand...

George H.
Pps. The email address in the header is just a spam-trap.
--
Tom Crane, Dept. Physics, Royal Holloway, University of London, Egham Hill,
Egham, Surrey, TW20 0EX, England.
Email: T dot Crane at rhul dot ac dot uk
Click to expand...
 
Good enough.  I once had similar thoughts and went looking for a board
house that would make proto-type quantities of copper on flex...
Too spendy.
Click to expand...

There are overseas places that will do it for cheap. I'll have a look and see who we used in the past--it was very reasonable.

Cheers

Phil Hobbs
 
On Friday, May 24, 2019 at 6:52:22 PM UTC-4, pcdh...@gmail.com wrote:
Good enough.  I once had similar thoughts and went looking for a board
house that would make proto-type quantities of copper on flex...
Too spendy.

There are overseas places that will do it for cheap. I'll have a look and see who we used in the past--it was very reasonable.

Cheers

Phil Hobbs
Click to expand...

I went looking at flex again... for like a 50 ohm heater.
and they wanted $50! Nothing against China, but I like local,
US. Those vendor relations can last longer.
(maybe that's 'more true' for small operations.)

If you ever need glass work, optical reference cells.
Precision Glass in Co. is one of my favorite vendors.
(sorry that's mostly random thought, 'cept I'm ordering more
stuff today. They make the bulbs for our Rb lamp now...
thought that is a rather boutique part.)

George H.
 
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