Flexible Circuit Using ECAD Functionality

[kwillo]

Has anybody ever designed a flexible circuit board using Pro/E's ECAD functionality (place regions, keep outs etc)?


I need to be able to show the partinits bent form and also in itsflattened form, ideally with place regions andkeep-outs etc. It would also be good to be able to showcomponents imported from our layout tool (Allegro) via IDF import.


I would be grateful for any ideas or suggestions on the best method for achievingthis? I'm using Pro/E 2001.


Thank-you.

 

[Dell_Boy]

A few questions,

Is your PCB several areas of laminate linked by portions of flexible polymer or is it ALL flexible polymer?

Can the whole PCB be characterised as several planar areas linked by reasonably simple 2D curved areas?

Do you really NEED the ECAD areas to wrap around curved surfaces in the folded state?


DB

 

[kwillo]

DB,


It's 2 rigid sections linked by an embedded flexible layer. All the ECAD areas are on the rigid part so I don't need those to wrap around the curved surface. I do however need them to move with the rigid parts in the flat and formed states.


I've managed to create a model that seems to work using the sheetmetal bend features and family tables to create various folded states. I think it may be slightly over-engineered!


KW

 

[Dell_Boy]

While I haven't specifically done flexible PCBs in ECAD, I have done breakoff PCBs in ECAD where a large PCB has one or two small pieces broken from it.

I had to have the parts joined together to export the .emn file but broken and re-oriented in the assembly drawing and all PCBs were populated so in principle these sort of things can be achieved.

I used the generic of the assembly for the unbroken state and an instance for the broken state and all parts of the PCB part were in a single PCB part

It sounds like you have solved your problem but do you still need help?


DB

 

[kwillo]

I think I have arrived at a reasonable solution for this one thanks. The EMN export did catch me out for a while because Pro/E is expecting a constant thickness. The flexi doesn't have a constant thickness in it's flat form so I had to use a couple of protrusions to pad the flexible part up to the thickness of the rigid part. The EMN then exported OK and I supressed those features in the generic (formed) state.


Thanks for your time.


KW

 

[Tobyk]

There is a way of doing this:


Create your flex circuit in sheet metal. Create an unbend all and then supress it (or create a flat pattern, same thing). Add your ecad default coordinate system.


Create a circuit assembly with your flex circuit as your first component.


Still in the assembly create assembly feature points on the surfaces of the flexcircuit where you want your components located. (pick the surface and then the nearest bend line feature or edge for that section of the flex circuit)


Create a point on the bottom surface of the component. (I use either the central location or PIN1 location ie same spot as your ECAD_DEFAULT coordinate sytstem)


Assemble your components on the circuit point to point and mate the surfaces to get the orientation.


Now in the model tree resume the flat pattern of the flex circuit part.


Regenerate the assembly


Here's the TRICK: If the components don't move, select all the components and the assembly points at once. Supress them and then Resume them.


Presto, the components will now be aligned on theflat circuit.


Here's an example I made in WF 2.0


2006-04-25_205802_FLEX-EXAMPLE.zip


Cheers,


TJK

 

[Dell_Boy]

Slightly off topic but I haven't used "flat pattern" since it was introduced in about version 17.

When I initially tried it out I was using sheetmetal to model the ribbon cable for ribbon cable looms so I could show them in the folded and unfolded states.

However when I used "flat pattern" to unfold the ribbon cable the attached connectors would not update their positions correctly but with "Unbend All" they would so I have done it that way ever since. Exactly the same reasoning goes for threaded inserts that need inserting into sheet metal before folding but this is used much less.

It would be nice to think that PTC have addressed this problem, but having to suppress and resume components every time you want to fold or unfold it is not a suitable long-term workaround. If you are having problems with Flat Pattern, try Unbend All.


DB


Edited by: Dell_Boy

 

[daveyk_belgium]

DB<?:namespace prefix = o ns = "urn:schemas-microsoft-comfficeffice" />


Nice Nick DB. A Pro/E user in NZ eh - any <?:namespace prefix = st1 ns = "urn:schemas-microsoft-comffice:smarttags" /><st1:country-region w:st="on"><st1lace w:st="on">UK</st1lace></st1:country-region> connections to the Trotters?


Regarding the sheet metal inserts, why would you want to show the inserts in the flat-pattern? I think that PTC won't address such an issue as this isn't a deliverable, but something that is part of the process of making your sheet metal assembly.


I have a lot of experience with sheet-metal. We have a part file for the sheet metal component

 

[Dell_Boy]

Sometimes you have to insert PEMs before folding, sometimes in the flat state, sometimes partially folded, because it is difficult or impossible to do so when fully folded.

Usually, but not always, the PEMs involved are flush F series because they don't interfere with the press-brakes and you can use them when often nothing else will work.

Doing a partial process assembly drawing for the sheet metal supplier helps them ensure that ALL the pre-inserted PEMs are put in the right place from the right direction, which means fewer rejects and this translates to a lower part cost.

I have been doing a similar process with respect to dimensions for about 8 years now because the process is so bullet-proof

No relations but our old next door neighbours were Trotters living in a straw bale house and to cap it all for a few years there were 3 of them.



DB


Edited by: Dell_Boy

 

[kwillo]

Just thought I'd post my method for creating the flexi should anyone be interested .


For the part:


1. Create the flat form of the flexi in sheetmetal.


2. Add the rigid section as protrusions, in my case I had 4. It's important to do them individually or they won't move with the fold later. You have to play around with the thicknesses to get the correct overall thickness, it might result in the individual layers not being quite right.


3. Add ECAD areas, other cuts, holes etc. Again, reference them to the features on the rigid sections so that they move later.


4. Create a bend feature/s to form the flexi into the desired shape.


5. Now create a family table instance called 'flat' which ignores the bend feature.


For the assembly:


1. Create an assemblyof the generic with all the components.


2. Create a family table instance which uses the flat instance of the part rather than the generic.


You now have parts and assemblies in flat and folded forms. I did have to be careful with the order of features in the part.


If you want to create anEMN export of the flat flexi you'll need to create protrusions on the flexible portion to make the thickness up to that of the rigidisers. I got an error in the export when the thickness across the part wasn't constant.Create these features in the instance called flat and surpress them in the generic part as they won't regenerate when the flexible part becomesfolded.


I found that if I redefined a feature on the part with the assembly in session it sometimes flicked the components to where they would be for the flat assembly and left them there. Regenerating wouldn't solve the problem but Tobyk's, supress/resume the components trick did. Otherwise once thepart and assembly are complete it all works fine.


There you go,maybe not the most elegant solution but itworked for me!


KW