Phil, have you considered plasma etching as a precursor process to replace
the media blasting and priming?
---
*Douglas Pauls *| Principal Materials and Process Engr | Advanced
Operations Engineering

*COLLINS AEROSPACE*

400 Collins Road NE, MS 108-101, Cedar Rapids, IA  52498  USA

*Tel:* +1 319 295 2109 | *Mobile: *+1 319 431 3773

[log in to unmask]

[log in to unmask] for all Export Compliant Items


On Wed, Feb 10, 2021 at 2:22 PM Nutting, Phil <[log in to unmask]>
wrote:

> Technetters,
>
> We build several power supplies that use RTV in place of dielectric oil
> for our high voltage multipliers.  The RTV allows us to get the same output
> level in a smaller package than a similar design using the dielectric oil
> as the insulator.  The proper process is to medial blast (lightly) the
> circuit boards, prime them and then encapsulate the boards in the RTV.
> Both the media blasting and priming can be very subjective processes.  And
> both have process issues in our manufacturing group. Simply eliminating the
> media blasting and priming is not a solution as the RTV will not bond to
> the boards and ultimately creating the potential for arcing to ground.
>
> Ideally potting a small box makes a disposable assembly, so the bonding
> quality and thermal size change of the RTV is not an issue.  We use between
> 20 and 100 pounds of RTV per potted assembly.  Disposal or repair of failed
> units is expensive.
>
> I am looking for folks that use RTV for encapsulation and what they use
> for a process to ensure good bonding between the RTV and circuit boards.
>
> Phil Nutting | Senior Development Engineer | Lab: +1-978-224-4334 |
> Mobile: +1-978-828-8664
> 35 Congress Street | Salem, MA 01970 | U.S.A. |
> https://urldefense.com/v3/__http://www.excelitas.com__;!!MvWE!RvNfmHfWkeL4GgrGmA1Nvnj_KcVjcEvSNd2kV5rS-q9gIbvJwBocVG72L1TuglEahw$
> <
> https://urldefense.com/v3/__http://www.excelitas.com/__;!!MvWE!RvNfmHfWkeL4GgrGmA1Nvnj_KcVjcEvSNd2kV5rS-q9gIbvJwBocVG72L1SkdEENsQ$
> >
>
> [cid:[log in to unmask]]
>