Shake proofing PCB assembly - Page 1
Forum section: electronics / projects

author: IconicPCB
author_rank: Super Contributor
timestamp: June 07, 2018, 05:07:14 am
content: A PCB assembly consisting of heavier components ( relays ) need to live in an engine bay subject to high levels of vibration.The assembly needs to survive extended periods of operation in this environment.I have been wondering what the better way of construction might bea) composite rigid flex laminate where the rigid part carries the weight of components while flex layers carry signal and allow for board vibration and solder joint survivalb) an extra heavy rigid panel construction in the hope it would be able to survive the vibrations say a 3.2mm or even heavier FR4 constructionc)... your recommendation please

author: JS
author_rank: Frequent Contributor
timestamp: June 07, 2018, 05:08:29 am
content: Potting?JSEnviado desde mi LG-M250 mediante Tapatalk

author: Twoflower
author_rank: Frequent Contributor
timestamp: June 07, 2018, 05:32:50 am
content: Mounting the relays not on the PCB but on the housing and using connectors that have decent locking mechanism is not an option?Also check the specification of the relays. The vibrations could shorten the lifetime of them dramatically.

author: Whales
author_rank: Super Contributor
timestamp: June 07, 2018, 05:55:18 am
content: QuoteThat would be interesting. Presumably automotive relays can handle a lot more than other types, but I'm not sure what type of engine, mounting and bay Iconic has.On that note: why not look at what's used in the automotive world? If some vehicles have "generic" relay boxes with wires coming out then it might be possible to use some of those.

author: IconicPCB
author_rank: Super Contributor
timestamp: June 07, 2018, 06:14:44 am
content: The intent is to use Bosch mini automotive relays as used in modern cars. These relays are typically rated in the region of tens of amps and will in fact carry such high currents in operation.They relays will be plugged into sockets.The problem is not so much the relay surviving the vibration but more so the PCB solder joints not cracking.Failed joints or failed copper tracks would result in further accelerated failure due to increased heat generation in the board.It is this aspect of the board which is of main concern.

author: timpattinson
author_rank: Contributor
timestamp: June 07, 2018, 06:22:59 am
content: Is it possible to shock mount the board or enclosure?

author: IconicPCB
author_rank: Super Contributor
timestamp: June 07, 2018, 06:28:20 am
content: Hello Tim,I do not know ...yetThe preallocated space is at a premium. I suspect i wont have too many degrees of freedom in this regard.

author: Twoflower
author_rank: Frequent Contributor
timestamp: June 07, 2018, 06:44:09 am
content: Quote from: Whales on June 07, 2018, 05:55:18 amI totally agree, there are relays out there that can survive such an environment. Learning later that the chosen type has a problem with that costs probably more than just a replacement because of burned contacts a redesign of the board might be required. Maybe thatinfo pagesmight be useful.

author: Whales
author_rank: Super Contributor
timestamp: June 08, 2018, 02:38:38 am
content: Quote from: IconicPCB on June 07, 2018, 06:14:44 amHow do cars mount them? On PCBs, or sockets in plastic with wires going out? Either way you might find looking at them useful, and you can probably buy these boxes new as well as used.