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Battery Cap Design Review

Battery Cap Design Review

Battery Cap Design Review

(OP)
Greetings everyone!

I am a junior mechanical design engineer charged with designing an injection moulded enclosure for an electronics device designed for submergence up to 300m.

Specifically I am looking for some feedback regarding my design for the battery cap.
-The battery cap will act as the contact for the positive terminal of the battery making electrical contact with the battery via a spring secured to the cap.
-The battery cap will also make electrical contact via its threads to the interior housing of the battery compartment.
-It will seal against the ingress of salt water via an O-Rig Seal
-No metal components will be exposed to salt water due to corrosion and electromagnetic issues.
-The battery cap will be operated by the use of a coin or washer.

So I decided on a 2 material cap, I have attached the two part files as well as a pdf with some images.

The interior part will be machined aluminium, the exterior part moulded ABS. The O-Ring groove is dimensioned for a Parker 115 O-Ring. There is a M18x1 male thread on the interior part.

An M3 self tapping screw will secure the interior and exterior halves together while also securing the spring that makes electrical contact. The protruding "teeth" will transmit the torque of removing and installing the battery cap.

My concerns are thus:
Water Ingress:-
-Is it plausible that water could ingress along the join between the two parts, this would be sealed by the O-Ring right?

Repetitive Torquing:-
-The battery will be removed and installed frequently through its lifetime, could this two part design result in failures due to the ABS failing with such thin wall thickness?

Electrical Contact:-
-The M3 self tapping screw will be passing through a through hole and binding into the ABS. The electrical connection will be made by compressing the spring against the interior aluminium part. How reliable will this set-up be for electrical connection, could the self tapping screw "back off" with time and result in a poor connection?
-The M18 threads making electrical contact with matching aluminium threads in the battery enclosure. Does anyone have experience with
this type of set-up, specifically any issues they have encountered?

Thanks for the feedback!
 

RE: Battery Cap Design Review

(OP)
Also, if someone could briefly tell me how I can A) edit posts and B) attach more than one file I can supply the part files for the batter cap if anyone wants them.

RE: Battery Cap Design Review

A. You can't after you've posted - in extreme cases you can ask management to make edits but that can take a while and it's not fair to expect them to make major changes.

B.  Instead of auto inserting, manually cut and paste the address into the message.

Posting guidelines FAQ731-376: Eng-Tips.com Forum Policies http://eng-tips.com/market.cfm? (probably not aimed specifically at you)
What is Engineering anyway: FAQ1088-1484: In layman terms, what is "engineering"?

RE: Battery Cap Design Review

Not everyone can open "sklprt" files.  Consider a different format. (You might also want to make sure that your company is ok with posting them on the web.)

Patricia Lougheed

******

Please see FAQ731-376: Eng-Tips.com Forum Policies: Eng-Tips.com Forum Policies for tips on how to make the best use of the Eng-Tips Forums.

RE: Battery Cap Design Review

(OP)
They are sldprt files, the default solidworks format. Which file type would be more universal? And I have talked to my company they are fine with it.

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