Comment by gene-h

4 years ago

High tech electronics can be quite sensitive to small contaminants in manufacturing equipment. A plant making HDDs accidentally lubricated some of the machinery with silicone which turned out to be very bad. This silicone got into the disks and as the head passed over the disk it got hot enough to decompose the silicone oil into silica. So effectively, the hard drive disk got covered in sand and caused the hard drives to fail much faster.

The worst part is that silicone oil will diffuse over surfaces so the whole plant got contaminated and needed to be scrapped.

I've also heard that some electronics plant had an issue where some metal tiles in the lobby of the plant were growing tiny whiskers of zinc, which got tracked in by workers and started shorting out the electronics.

Reminds me of old stories about Intel - how, when they were taking a (chip fabrication) process which worked at plant X to (new or re-tooled) plant Y, they would duplicate EVERYTHING from X at Y. Right down to the exact brand / line / formulation of the paint on (say) the walls of the lobby, the type of toilet paper in the bathrooms, etc.

I was watching a video about the gold coating on the JWST primary mirror segments and noticed a conspicuously placed sign warning employees not to bring anything containing silicone into the facility.[1] I had no idea it was such a problem contaminant! I wonder if they have issues with personnel using silicone based personal products at home.

[1] https://www.youtube.com/watch?v=fgn7bKs042Q&t=211s

Siloxanes are serious contaminates in several industrial processes. Another big one is powder coating "paint". It can be bad even if only comes from a personal care product used by an employee at home.

And you called out their near-infinite ability to be spread around.

Very useful and interesting class of chemicals.

Scrapped or scraped? Did they really need to abandon the plant or the equipment, or just clean it?

  • Silicone oil is one of the most stubborn contaminants I have ever encountered. I use trisodium phosphate to clean it up, and even then it sometimes persists. Try pouring epoxy over wood that has been polished with Pledge, and you'll see what I mean.

    I can believe "scrapped."

    • Isn’t a silicone based oil used in oil diffusion vacuum pumps?

      Seems like one should look for a different solution

Not a clean room, but reminds me when I was working in a partner's small datacenter and found an electrician in there using a chop saw on metal conduit.

Are there sources for both of your stories? I would be very curious to learn the details.