Amazon will seemingly go to any length to get the things your purchased to you as quickly as possible. Once upon a time, during checkout you had a few shipping options, and the more you paid, the faster those brown boxes arrived. Then the company introduced Amazon Prime, a membership program that basically creates a flat-fee structure for next-day shipping. But that wasn't enough for Amazon CEO Jeff Bezos, so same-day shipping was introduced for certain products, in certain locations, including groceries with AmazonFresh. If you live in Manhattan or Brooklyn, you can even get one-hour shipping.

But why stop there? A little over a year ago, just in time to get some media buzz for the holiday shopping season, Amazon unveiled its aerial delivery drone project. The general idea is that small, time-sensitive orders could be rushed to customers via small computer-controlled flying drones that would drop packages directly at your front door within hours (maybe even minutes, if you are close enough to an Amazon warehouse). But this is an ambitious project that will run into many technical and regulatory hurdles, so don't expect to see those drones obscure the sky any time soon. This idea of autonomous flying vehicles has also made some people wonder if Amazon might not also be working on self-driving delivery trucks.

Amazon's patent for a 3-D printing on-demand delivery service

Amazon's patent for a 3-D printing on-demand delivery service. (Image: U.S. Patent Office [public domain])

All these efforts to make sure people get their packages faster apparently still aren't enough: a new patent filing by Amazon shows that the company is looking into using 3-D printers inside delivery trucks to create a kind of miniature factory on wheels to ensure that people who order things that aren't in nearby warehouses, or things that are custom-made in some way, can get them rapidly. (Don't expect this level of service come free with a Prime membership, though, I'm sure it'll be extra — a whole lot of extra.)

3-D printing, also known as additive manufacturing, is the process by which a special printer can build a 3-D object layer by layer, starting from the bottom and going up. It's similar to how an inkjet printer will print something on a piece of paper, except that the process is repeated many times for each layer and what come out of the printing head is a special compound that hardens rapidly rather than ink. Lately, 3-D printing has also been used to mean subtractive manufacturing, where the starting point is a solid block of material, and computer-controlled milling machines literally sculpt the desired product.

At first, this level of sci-fi technology might seem completely overkill. This can't be cheap, right? Why not just have slower shipping rather than spend the extra money for mobile 3-D printing? But when you read Amazon’s patent filing, it becomes clear that this type of approach could actually help Amazon save some money by reducing its warehouse space needs, because having everything in stock — literally millions of products — requires many large expensive warehouses close to population centers, and in many places, land is not cheap. What if you could have smaller warehouses, and just make-to-order some of what you don't have in stock?

"The multiplicity of items offered may require the electronic marketplace owner/operator to maintain a large inventory requiring sufficient space to store the inventory," states the patent filing. "An electronic marketplace may also face the challenge of time delays related to the process of finding the selected item among a large inventory. Increased space to store additional inventory may raise costs for the electronic marketplace. Additionally, time delays between receiving an order and shipping the item to the customer may reduce customer satisfaction and affect revenues generated. 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."

A 3-D printer at work in a Makers Party in Bangalore

A 3-D printer at work in a Makers Party in Bangalore. (Photo: Wikimedia Commons)

Of course, this is just at the R&D stage. But as 3-D printing keeps improving and becoming cheaper, maybe we'll see this system being deployed for certain time-critical and custom-made products.

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Michael Graham Richard ( @Michael_GR ) Michael writes for MNN and TreeHugger about science, space and technology and more.

3-D printing ... inside a moving delivery truck?
Amazon continues to look for new ways to deliver things to customers even faster.