Amazon(AMZN -0.64%) has made speedy delivery one of its key priorities.

To accomplish this task, the company has developed a nationwide network of distribution centers, built up its own delivery force, and made a deal with the United States Postal Service for Sunday delivery. The company has even tested predictive software, so it can know what you plan to order before you order it, and it has been experimenting with unmanned drones for near-instant delivery.

A new patent application from the online retailer shows it wants to take things a step further by removing warehouses from the equation. The patent, titled "Providing Services Related to Item Delivery Via 3D Manufacturing on Demand," details a process where Amazon would take orders and use 3D printers in its delivery trucks to create the items.

This graphic from the patent application shows how the process would work. Source: Screenshot

"TIme delays between receiving an order and shipping the item to the customer may reduce customer satisfaction and affect revenues generated," the company explained in the "background" section of its application. "Accordingly, an electronic marketplace may find it desirable to decrease the amount of warehouse or inventory storage space needed, to reduce the amount of time consumed between receiving an order and delivering the item to the customer, or both."

How it works 
While the application does not specifically say items would only be manufactured in the truck, it does provide graphics and examples where products would be printed in the vehicle. In a broad sense, the process starts when Amazon receives an order from a customer. Then, the company interfaces with its supplier to receive drawings for the product and to arrange payment. After that, the item is printed and dropped off to the customer, either at their home or workplace or perhaps, at an alternate location like an Amazon Locker.

A specific scenario
Amazon spells out a specific example where a faucet handle breaks off while a person cleans up after dinner, making adjustment of the water pressure and temperature difficult. The person would then use a smartphone to access Amazon, locate the replacement handle, and order it for remote pickup.

After the order is completed, the customer, according to the application, would head toward the pick-up location indicated by the retailer.

"Meanwhile, the computer systems retrieve a digital 3D model of the faucet handle from a database maintained by the original vendor of the faucet," Amazon wrote. "The computer systems then convert the 3D model into printing instructions for a 3D printer."

Those instructions are used to print the handle -- either on a truck or at an Amazon facility -- and by the time the customer arrives at the pick up location, it is ready.

This specific example has the item printed in a physical Amazon location, but the patent application details both fixed and mobile scenarios as well as customer pick ups and deliveries. In either case, the time between order and pickup is dramatically faster than even the one-day option Amazon currently offers (and equal to, if not faster than, the very-limited same-day service offered in some markets).

More items, faster
The promise of making items using 3D printers not only offers quick turnaround but also the potential to exponentially increase product offerings. If the retailer can make deals with manufacturers, it should, for example, be able to offer an exhaustive supply of replacement parts. This could, in theory, include items that are out of stock or no longer manufactured. 

Though the patent does not spell out how close Amazon is to offering this type of service, it does lay out an intriguing scenario which would improve service and inventory management without adding warehouse space. This type of service could be revolutionary, with the caveat that 3D printing and "parts on demand" are likely to become more common with physical retailers in the future.

Still, despite the fact that Amazon may someday be competing with "Print It Hut" or "On-Demand-O-Mat" locations in every strip mall in America, this is a bold idea typical of a company always pushing for innovation.