Printed Circuit Board Assembly & PCB Design SMT Electronics Assembly Manufacturing Forum

Printed Circuit Board Assembly & PCB Design Forum

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Assembly of flexi (flexible) circuit boards



Assembly of flexi (flexible) circuit boards | 26 June, 2003

We currently have a requirement to build flexi circuits and mount two 40 way, 20 thou connectors at each end. The flexi pcb's arrived in singlulated format. Ideally we would like to have the circuits panelised for machine building as hand placing the connectors is not really an option. We also have no fiducials for any kind of placement accuracy. As far as I can tell to actually manufacture in volume we would need some kind of carrier for machine transport purposes, this sounds easy enough but how do we hold the circuits flat? Using high temperature tape is an option , but again to manufacture in volume we want as little handling as possible. Can anyone advise if they have been 'challenged' with this before. Thanks in advance.

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Assembly of flexi (flexible) circuit boards | 26 June, 2003

We had a "Spring loaded" fixture that pulled the Flex tight and used loads of Board supports. There were pins that went through the Connectors holes and held the flex firm. We only had a few components so it was no problem. Lucky for us because the fixture going through the reflow process acted like a big old heat sponge.

We also did not have fiducials so we used the through-hole pads as fiducials. We taught the location as a unique fiducial.

NOTE: Our success with this was for pure R&D and was marginal. I could not imagine going into full production.

Cal Driscoll Communications Test Design, Inc.

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Assembly of flexi (flexible) circuit boards | 26 June, 2003

We have been processing a 3 and 5 up flex array for nearly four years on pallets and have had a pretty steep learning curve. Make sure you have vacuum holes in your pallet for the screen printing process, also work with your support block vendor to make sure you get the right vacuum support block for the system, make sure the vacuum is only drawn on the break away area of the circuit. After printing we place a 1/8 inch custom metal hold down plate on the circuit to flatten it out for paste inspection and part placement, verify the plate doesn't shade any of the fiducials or interfere with the placement machines capabilites.

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