Hi all,
This may sound funny but has anybody has ever seen or heard of such thing as transparent or clear (see through) PCB?
I am just curious. If there is any, I think they will be very useful in assembling some types of ICs like BGA for example.
Regards
Flex circuits can be clear. They're fairly spendy, however. I've also seen some PCBs that didn't have soldermask that were somewhat transparent - maybe if you had a super thin PCB made you could get it really clear?smdFan:
Hi all,This may sound funny but has anybody has ever seen or heard of such thing as transparent or clear (see through) PCB?
I am just curious. If there is any, I think they will be very useful in assembling some types of ICs like BGA for example.
Regards
This is only very slightly related to your question, but I have a recent experience at work that might shed some light on the question of flex circuits being spendy.
We have a device at work that has a sensor that moves back and forth with a little stepper motor. There is a 10 pin flat ‘flexible’ cable (NOT a flex circuit like you’re thinking of, but a real cable that has thick copper wires embedded in plastic) that goes from the mainboard to the sensor. We originally used off the shelf cables from Molex because that’s what the sensor manufacturer recommended. They cost about $1.80 each in low quantities.
Turns out the cable only had a rated life of like 5000 flexes. We saw a ton of cracked/broken cables. So we had to go to a true flex circuit. I was totally worried about the cost (because we are in such low volume). Molex has a division that does custom flex cables, and they wouldn’t even talk to us because our volumes were so low.
We found a small flex circuit vendor who created exactly the cable we needed, and even added a special type of rigid backing on one end (very non-standard). The new cables work perfectly, and are rated for millions of flexes. And the best part? The cost. They built me a single panel of prototype cables (50 or so) for something around $250. When we approved the design, they just sell us the individual cables at about $2.10 each, as long as we buy at least 100 cables at a time. I couldn’t believe that a completely custom solution, with special dies to cut the cables out, etc. cost only slightly more than the crappy off the shelf version. And the NRE cost was only $250!
We could have easily made these cables see-through (clear) I believe - the way they are now they are translucent with a slight brown color to them. I’m sure you can have your circuit custom made by a flex circuit company - shop around. You can get a good price I think. But you’ll probably have to buy a whole panel’s worth.
The tricky part would be soldering a big part like a BGA to something that’s as flexible as a flex board. However, I’ve seen complete 16-bit microcontrollers (100 pin) soldered directly to a flex circuit in a digital camera, so it can be done.
*Brian
Hi Brian, could you tell us which flex circuit house that was?
Yup! Here they are http://www.allflexinc.com/ They’re in Northfield, MN - not too far from where we are. They were extremely helpful, took my napkin drawings of what I wanted and turned it into real artwork, then built the first panel of cables all in under 4 weeks. Granted I’ve only had one experience with them, but it has been very positive.
*Brian
EmbeddedMan:
Yup! Here they are http://www.allflexinc.com/ They’re in Northfield, MN - not too far from where we are. They were extremely helpful, took my napkin drawings of what I wanted and turned it into real artwork, then built the first panel of cables all in under 4 weeks. Granted I’ve only had one experience with them, but it has been very positive.*Brian
Can you say how much you pay for what?
Thanks!
jeanseb - they build a cable for us that’s about 4 inches long and about .75 inches wide with about 20 conductors on it. (This is all from memory since we did this quite a while ago.) It has traces on one side. One end just has a thick plastic (Kapton?) tab that helps us insert it into the circuit board. The other hand has a thin glued stiffener on it that forms a sort of ‘guide’ to prevent the cable from bending in the wrong direction.
I believe we order these about 1000 at a time, and I think they’re maybe $2 each? I could be off by a bit - call them up and ask for a quote. They were super helpful and friendly about teaching me everything I needed to know to get the custom cable build. (I’d never done this before and knew nothing.)
*Brian
EmbeddedMan:
jeanseb - they build a cable for us that’s about 4 inches long and about .75 inches wide with about 20 conductors on it. (This is all from memory since we did this quite a while ago.) It has traces on one side. One end just has a thick plastic (Kapton?) tab that helps us insert it into the circuit board. The other hand has a thin glued stiffener on it that forms a sort of ‘guide’ to prevent the cable from bending in the wrong direction.I believe we order these about 1000 at a time, and I think they’re maybe $2 each? I could be off by a bit - call them up and ask for a quote. They were super helpful and friendly about teaching me everything I needed to know to get the custom cable build. (I’d never done this before and knew nothing.)
*Brian
Well $2 a piece is cheap, though it’s Q=1000 that is painfull.
For a proof of concept, I can’t seem myself ordering 1000, or paying $2000 for.
I’m currently getting quotes from several companies. I hope it’s not going to be as expensive.
so far, my experience with this type of industry is that the price is pretty much a flat rate. they need to develop tools etc… So all in all a batch costs $2000. If you want 1000 piece then each piece will cost you $2. If I want 10 pieces, each piece will cost me $100 or so… It seems to be similar to the overlays industry.
If you’re a company and haven’t used them before, Advanced Circuits has a “$500 free” program for new customers… and they do flex circuits. Haven’t used them for a flex design yet, but I have used them for several standard boards.
(I don’t have any affiliation with Advanced Circuits, just a customer. The others I recommend are Batch PCB (duh!) and Gold Phoenix, depending on project requirements)
http://www.instructables.com/id/DIY-Fle … -Circuits/
This may be good for proto.