I was thinking of polyimide type circuits. I believe these are the type use= d in such things as cameras. I was hoping that it would be more easily shap= ed into place than FR4. One of my constraints is that placing the circuits = in the 'housing' will be done by untrained people (electronically untrained= that is). Reflowing after bending is not an option. My feeling is that an = FR4 board will tend to bend everywhere thus putting stress on components, w= here a polyamide board will bend where it is easiest to do so (not under co= mponents?). There are areas where I know there will be less bending, so onc= e I place the bulk of components there, I should be OK. The 12f675 has a bi= g footprint though. Sadly I only need 4/6 inputs & little processing power.= I may find it worthwhile to look at other options. Size & power are most i= mportant to me in this case. Once in place, the circuit will not be moving. I think I'll also have to do double sided PTH. Joe -----Original Message----- From: piclist-bounces@mit.edu [mailto:piclist-bounces@mit.edu] On Behalf Of= Brent Brown Sent: 14 September 2010 22:53 To: Microcontroller discussion list - Public. Subject: Re: [EE] Flexible PCBs Joe McCauley wrote: > Has anyone any experience using these? I need to make a pcb to fit > into a curved (in the plane of the PCB) and restricted space. To > complicate matters, the curve will not be the same in all cases. I > thought a flexible PCB would work, but am concerned with how to > solder one reliably. Has anyone any experience with mounting > components on these? I will only have to do a couple of prototypes, > any more will be someone else's problem. The sort of stuff going on > it is an rfPIC (12F675) & some passives as well as battery > management circutry such as charger and boost converter.=20 >=20 > I wonder if anyone here has experience with working with these who > could offer some pointers. Also will bending the rfPIC loop antenna > significantly affect operation?=20 >=20 > Thanks for any pointers, I have done flexible with "standard" FR4 of 0.2mm thickness, wrapped around= a=20 metal tube of approx 70mm diameter, held with cable ties. My PCB company sa= id=20 they could do either 0.1or 0.2mm thickness fairly easily as these are stand= ard sizes=20 used in laminating of multilayer boards. From memory I seem to recall 0.2mm= was=20 the thinnest they could do PTH. As my board was a hand assembled prototype I soldered all the parts by hand= (all=20 SMD) when the board was flat, then re-worked each component with the board = in=20 the final round shape to release the stresses. When designing I tried to or= ient each=20 component so its shortest axis would align with the bend. --=20 Brent Brown, Electronic Design Solutions 16 English Street, St Andrews, Hamilton 3200, New Zealand Ph: +64 7 849 0069 Fax: +64 7 849 0071 Cell: +64 27 433 4069 eMail: brent.brown@clear.net.nz --=20 http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist --=20 http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .