1 / 6

Conformal Coat Quality issues

Conformal Coat Quality issues. Update of November 3, 2004. Thorough Visual Inspection Done. Have done a very careful inspection of about 300 boards. Virtually all have some problems. All are documented in a spreadsheet

rdriskell
Download Presentation

Conformal Coat Quality issues

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Conformal Coat Quality issues Update of November 3, 2004

  2. Thorough Visual Inspection Done • Have done a very careful inspection of about 300 boards. Virtually all have some problems. All are documented in a spreadsheet • About 50 have virtually no CC on the sides of many components. Most have no CC near the encapsulant including on a few solder pads. • Most have CC lifting on the top or sides of some components. Locations are documented. • A few have a visible contaminant. • A few have small gold nodules in the grounding screw holes. • A few have CC problems near the screw holes • Many have CC in the connectors.

  3. Plans to fix production problems • Production at Teledyne is shut down while process changes are devised to reduce these problems on future boards. • Not the topic of this meeting, but • Will spray CC from multiple directions • Consider adding cleaning steps so CC will bond better • Learn to mask the connectors better

  4. Lifting Tests • Have thermal cycled 5 board 200 times. Lifting did not get worse. • Have vacuum cycled 4 boards 3 times. Lifting did not get worse. (See separate report).

  5. Proposed Action Plan • no CC on the sides of many components and near the encapsulant. • Fix by cleaning and applying coating with a brush. • CC lifting. • Leave as is • Visible contaminant. • Judge by size and location whether to leave or remove and recoat • A few have small gold nodules in the grounding screw holes. • Fix by scraping off. This will leave a non-gold plated spot in the hole, but it is the head of the screw that makes the electrical contact. • A few have CC problems near the screw holes • Fix because they are few and it is easy. • Many have CC in the connectors. • Fix by carefully removing loose CC.

  6. CC lifting risk analysis • Vacuum and thermal tests indicate it won’t get worse. • Purpose of CC is to keep conductive contaminants from shorting between 2 metal things. It will do this even though it has lifted a bit. • Using tweezers to remove CC from these tiny components and then recoating them is more likely to cause a problem than fix a problem.

More Related