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!
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!
