The new 3D printers are coin-size systems.

"The tiny device could enable a user to rapidly create customized, low-cost objects on the go, like a fastener to repair a wobbly bicycle wheel or a component for a critical medical operation. Credit: Sampson Wilcox, RLE" (Scitech, Tiny Titan: MIT’s Revolutionary Coin-Sized 3D Printer Fits in Your Pocket)

Researchers created a 3D printer that is coin-size. That kind of printer can create things like microchips. But it's possible. Those tiny 3D printers can also work in extremely large-size projects. In simplest models, the 3D printers are positioned on tracks. The 3D printer itself is the tool, that can be part of the modular production systems. 

There are visions of high-temperature metal printers installed on the gantry cranes. That makes those crane printers that can make even ship-size things. The crane that the printer controls can move back and forth and the printer can move horizontally. This kind of thing can turn the crane into a high-temperature 3D printer, that can produce large-size objects. 

The small-size 3D printers can installed on robot wagons or in small quadcopters. The ability to move on the ground and in the air makes those tiny robots create complicated 3D structures. The quadcopters that use 3D printers can print almost everything. The raw material can be metal wires that can be hung from a crane. And that material travels through printers. The printer can be below the crane and the raw material travels through the air. 

The idea is that the 3D printer system navigates using the precisely operating GPS. But it's also possible that there is a laser LED in those robots. The camera on the roof or on the drone that hovers above the working area follows the printers. The system requires 3 or 4 points that it can use the triangular measuring system to the precise location of the printers. 

The fact is this. Those small-size printers can fix damages on layers with very high accuracy. That kind of system can make anything. The raw materials are limited for the 3D-printed merchandise. And the miniature printers can make it possible to create new products and make repairments on the field. The miniature printers that are installed onboard ships can repair their damages. 

https://scitechdaily.com/tiny-titan-mits-revolutionary-coin-sized-3d-printer-fits-in-your-pocket/