Practical thinnest rigid 2-layers PCB

[Wilson__]

What is "Practical" thinnest rigid 2-layers PCB with 'some increase' but not skyrocketing cost? 

PCBWay or similar will make PCB and do assembly.  Hence has better tools, like optical and/or x-ray examination.  Also skilled people than if we doing assembly.

TIA

[ajb]

Best to ask your assembler, as it will depend on their capabilities and workflow, as well as your intended quantity and the size and assembly needs of your PCB.  Fabricating a super thin board is one thing, assembling components onto it is another.  Supporting the board during stenciling and placement will be more important the thinner and larger the individual boards are.  Some designs may require extra setup or even custom support fixtures, which could be very expensive if you're only building 5 units, or a negligible cost if you're building 5000.

[Wilson__]

Would 0.3 to 0.6mm be practical for quite small size pcb with light weight components (no heavy coil, just R C and chip)?

[T3sl4co1l]

As no specification was given, I am free to assume my own threshold.  I will therefore assume by "skyrocket" you mean "aerospace prices".  So, anything under thousands of dollars will suffice.

I can safely say all proto services that offer PCBs of any thickness, will be able to make anything as thin as they can, within that budget.

If you're rather more sensitive to price, you will notice fab costs generally rise around the 1 to 0.8mm thickness range, more or less because they are less common choices and therefore not so easy to pool multiple orders into panels.  Anyway, these options are all available from the most prominent fabs via online calculator -- pcbshopper.com is your best starting point.  Hardly any point in asking us when you can get exact numbers straight from the fab!

Tim

[mikeselectricstuff]

I've  done 0.1mm 2 layer, this was with a UK suppler who used the prepregs normally used for inner layers. I've also done some 0.2mm, don't recall where we got that from.
With thin materials like this, you need to take care to balance the amount of copper on each side to avoid warping during reflow.
Assembly isn't too bad if it's only one side - you just tape it to a piece pf thicker material with kapton tape. Double-sided will need jigs to keep it stable & is more involved

[coppice]

I've  done 0.1mm 2 layer, this was with a UK suppler who used the prepregs normally used for inner layers. I've also done some 0.2mm, don't recall where we got that from.
With thin materials like this, you need to take care to balance the amount of copper on each side to avoid warping during reflow.
Assembly isn't too bad if it's only one side - you just tape it to a piece pf thicker material with kapton tape. Double-sided will need jigs to keep it stable & is more involved

I've worked with 0.1mm FR4, but its a stretch to call it rigid. Its quite fun to roll them up into a tube, if the components are small enough to sit moderately flat on the surface.

[tszaboo]

Would 0.3 to 0.6mm be practical for quite small size pcb with light weight components (no heavy coil, just R C and chip)?

0.6 works for sure. You can add metal stiffener to the PCBs with relatively trivial cost, and make the PCB thin but still possible to handle.

[Wilson__]

How metal stiffener works?   Can metal stiffener be removed after reflowing?

[Wilson__]

pcbshopper.com says 0.6mm is still good price.    Would that be 'relatively' easy to have parts on both side for soldering?

[Wilson__]

Any idea what PCB thickness, 2 layers, components on both side, are used in 'mature technology' products like 'modern' fitbit, watch? 

'Modern' mean latest generation low cost, no/non-well-known brand products.

[mikeselectricstuff]

Any idea what PCB thickness, 2 layers, components on both side, are used in 'mature technology' products like 'modern' fitbit, watch? 

'Modern' mean latest generation low cost, no/non-well-known brand products.

They tend to use flex or flex-rigid/flex+stiffener rather than very thin FR4 - don't think I've ever seen much below 0.5mm FR4 in production designs

[coppice]

pcbshopper.com says 0.6mm is still good price.    Would that be 'relatively' easy to have parts on both side for soldering?

For a big board 0.6mm FR4 is quite bendable. However, if your product is fairly small its not much different from working with a traditional 1.6mm FR4 board, especially if your board is all surface mount. If you are expecting a big through hole part to gets lots of mechanical support from the plated through holes you might be disappointed, but you probably aren't doing that sort of thing is you are looking to save space with a thin board.

[jonpaul]

We used 10,000 pcs of 0.032" 0r 0.81 mm FR4 G10 in 12 kV HV multipliers.

No probles

Jon

[tszaboo]

How metal stiffener works?   Can metal stiffener be removed after reflowing?

There are two basic types, one the assembly house will use to temporarily attach to your PCB while working with the boards.
The other type is glued to the PCB, either to very thin boards or flex PCBs. This is of course non-removable.