HP isn’t content to just 3D print in plastic. A job ad for a “robotics scientist for 3D printing” sounds normal enough until you dive into the text and read this:
“HP Labs’ research into printing of inorganic materials is working towards hybrid printing of glass (and other inorganic materials) onto items that are already mass produced,” the ad reads.
3D printing is generally reserved for working with plastic and metal. Glass is unusual. But HP has its reasons. According to a 2012 HP Labs paper:
HP is due to release its first-ever 3D printer in October. We don’t know much about it except that it will be aimed at businesses and a potential boost for the ailing company. It’s unlikely it’s a glass printer though. This is a project that still lives within HP Labs.
Reference : https://gigaom.com/2014/09/26/hp-labs-is-working-on-a-glass-3d-printer/