Validating a Bonding Process

#1
Hi all,

I was tasked with validating a bonding process for potting a small stator into a machined housing using epoxy EC-1015. The motor and stator under use is enclosed in a tight space and is not subjected to too much force, however I am curious as to the most efficient and simple way of validating this bonding process.

Curious to know anyones thoughts on this.
 

John Broomfield

Fully retired...
#2
Hi all,

I was tasked with validating a bonding process for potting a small stator into a machined housing using epoxy EC-1015. The motor and stator under use is enclosed in a tight space and is not subjected to too much force, however I am curious as to the most efficient and simple way of validating this bonding process.

Curious to know anyones thoughts on this.
sev7nflow

Will the epoxy being such a good insulator stop the stator from doing its job?

All other characteristics of this epoxy seem well established:

https://www.epoxysetinc.com/wp-content/themes/twentytwelve/hightempPotting-pdf/EC-1015.pdf

Focus on how the gluing process ensures the epoxy only goes where it is meant to and on how tolerant the stator (performance-wise) is when contaminated with epoxy.

:2cents:

John
 
#3
Thanks for the reply. Currently I'm thinking the easy portion is out of the way in terms of defining amounts of epoxy (fixed amount since we have a glue channel to be filled thoruhg injection) and curing time, however my concern is the amount of torque the stator may experience while under load. What would a validation of the bond between the stator and housing look like?

Would I need to take 30 samples and torque the stators to our torque requirement and prove that the amount of epoxy & curing time exhibits a bond strong enough to withstand the forces of the motor?
 

John Broomfield

Fully retired...
#4
Thanks for the reply. Currently I'm thinking the easy portion is out of the way in terms of defining amounts of epoxy (fixed amount since we have a glue channel to be filled thoruhg injection) and curing time, however my concern is the amount of torque the stator may experience while under load. What would a validation of the bond between the stator and housing look like?

Would I need to take 30 samples and torque the stators to our torque requirement and prove that the amount of epoxy & curing time exhibits a bond strong enough to withstand the forces of the motor?
sev7nflos,

I’ve no idea how many samples you should test but the epoxy seems strong enough to withstand the torque.

Perhaps start with a literature search to see if this has been done before by a reputable lab such as the Livermore:

http://www.dtic.mil/dtic/tr/fulltext/u2/a638115.pdf

Looking at this paper for a pulsed duty alternator seems to be an example of epoxy withstanding extreme forces and it includes a sketch of the test rig.

But the amount of epoxy should not create a notch from which a crack may radiate and cause failure. The curing time should be standardized per the manufacturer’s instructions.

By stardardizing on the few vital variables you may find that the epoxy bonding is more than sufficient for the intended duty.

I would start small and only work up more samples if the epoxy bonding fails.

John
 
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