Click here to go to our main page on microwave packaging
Click here to go to our page on hermeticity
A seam sealer uses electrical resistance to create a welded joint that is hermetic, between a housing and its lid.
Here's some images we found on ebay, this setup was going for ~$35K recently. Below you can see that the "glovebox", which allows workers to set up the module but keep it in an inert atmosphere.
Below you can see the rollers which supply the electrical juice to form the weld. The typically pass in opposite directions.