Flexible PCBs

[CM800]

We have a product we are developing for a customer.

In effort to dramatically reduce the cost of assembly due to crimps, we want to move over to flexible PCBs for the signal interfaces (CANOpen, EtherCAT, RS485) and some of the I/O

the main plan is to have them go into FFC connectors and then over to the pins on circular style panel mount connectors.

Does anyone have any information about actually designing flexible PCBs and getting them manufactured?

[CM800]

The correct spelling is flexible.

Good point, fixed. For some reason auto-correct didn't show it up.

The design rule, from electrical perspective, is the same. You need more considerations on mechanical strength though.

Noted, I will have to design in some good slack due to how it will be installed and there will be a bit of a curvy bend as the connector it solders to is at 20 degrees angle

For manufacturing, I use some Chinese fabs, even I live in the US. US fabs are so expensive that the cheapest I know charges $375/panel for 0.5oz copper thickness, 6/6mil tracks.
The Chinese supplier I use offers the same specification, and charges $40 for 0.5oz copper and $60 for 1oz copper. So far, I have made 2 designs and I am satisfied. They only offer small number of small prototypes, not a whole panel, though.

That is good to know, what is your Chinese supplier?

we will start off with a small few prototypes, then upwards of 1000 or so.

[KL27x]

For protos, I have used Itead. Cheapest I have found. For small protos, as low as $99.00 for ten with approx. 3 week turnaround.

My domestic quotes for exactly the same thing and exactly the same turnaround were about 10x as much, at best. And up from there.

For large scale, check with w/e manufacturer you currently use. A lot of the big Chinese manfuacturers do flex. I have done large quantities with Gold Phoenix, and they are pretty great, IMO. They usually beat the lead time and everything is painless, except having to call my bank every time I pay them.

Specify the thickness and material of the substrate and of the overlay or coverlay, and the rest is just like a regular pcb.

E.g. 1mil thick polyamide with 1 mil thick coverlay both sides. (= 3 mil thick, total).

The coverlays are fused to the pcb and act as the soldermask. For fine pitch parts, there will not be a "soldermask" between pins/pads.

Not sure what quality you need. The coverlays on my FPC's are not always perfectly aligned. But I have heard this is par for the course, from assembly houses, anyway. (This might also increase your cost for assembly on fine pitch parts and/or decrease your yield post assembly. Flex doesn't stencil paste perfectly, due to distortion, and it can flex in a reflow oven). But I'm sure I could send them back if they didn't work, and so far everything is good on my end. Gold Phoenix has multiple chat support personnel that speak English. You don't need a broker. A very helpful rep has responded within minutes, on any inquiry I have made, all hours of the day.

[pcbfox]

Pls give me your email address, I will send you the design rules for Flexible pcb.

[chris_leyson]

My first flexi-rigid was a small panel with eight assemblies on it, all identical. Used coverlay as soldermask as I had used another flexi-rigid connector to connector assembly as a guide. Prototype panel arrived and all seemed well. Next thing, production manager gets a quote for building more, turned out that the prefered PCB supplier had to increase the manufacturing cost as they had to send the coverlay to another company to get it laser cut.

Damn, start all over again but this time sandwich the flex and coverlays between two rigid PCBs and use standard FR4 soldermask. It turned out to be cheaper to build, no laser cutting only drilling and through plating. Also, a few other PCB manufacturers recommend this sort of stackup as it is a cheaper option.

My second flexi-rigid was for translating an M12 X-coded industrial ethernet connector to RJ45, stackup was the same with the flex sandwiched between two layers of FR4. They worked out to be quite expensive £90 per circuit.

This time round, I've gone for FFC cable and connectors and a separate PCB at each end, one hell of a lot cheaper, and it seems you can route 1000Base-T through coplanar waveguide but I need to look at the signal integrity.

[moreab]

My board size is 5*4.5 cm. I want to make flexible PCB with 0.4 mm track width what will be cost and I am from India so which countries will give me PCB soon.

[moreab]

Please provide flexible PCB making company names or official sites?

[charlespax]

You can use the service from Dangerous Prototypes. Go to http://dangerousprototypes.com/store/pcbs and select "Flex PCB" as the material.

[technotronix]

Please provide flexible PCB making company names or official sites?

Flexible circuit board means the composition substrate lamination into single board that allow circuit board to find substitute of multiple printed circuit board interconnection with connectors, wires and ribbon cable to create a single printed circuit board. Here is a flexible PCB manufacturer name is given for your reference only. http://www.technotronix.us/flex-rigid-flex-technology.html

[mairo]

... Does anyone have any information about actually designing flexible PCBs and getting them manufactured?

You can look at the Würth Elektronik's design materials + they also manufacture (may not be as cheap if made in Asia). They have good design guide videos in youtube about flex/flex-rigid boards.

http://www.we-online.com/web/en/leiterplatten/produkte_/3d_starr_flexible_leiterplatten/Einleitung_3D_starrflex_leiterplatten_pcb.php