The manufacturing process for nylon plastic, the most common material, could be described as a blend of high-tech and high-school art class. Engineers approve the uploaded design files and assign them to a “build,” in which as many objects as possible, perhaps 1,000, are virtually fitted together, as if in a game of 3-D Tetris. The build comes out of the 3-D printers in a square cake of nylon powder. The cakes are cooled and the powder brushed off to reveal the objects inside, a process Raheel Valiani, the director of operations for the Queens factory, likened to an archaeological dig.

Young, hip-looking factory workers then sort the objects, hand-color some of them using boiled fabric dyes (white is the default shade for nylon plastic) and package and place them in the yellow bins to be shipped out.

Shapeways, which started in the Netherlands in 2007, as part of an incubator run by Philips, the electronics maker, initially outsourced its 3-D printing. Now there are two factories, one in Queens and the other in Eindhoven in the Netherlands; the one here is adding four printers to its fleet of 12, at a cost of $500,000 or more each. The hope is that the new machines will increase capacity, speed up work flow and bring Shapeways closer to its long-term goal of overnight fulfillment.

Of the thousands of objects printed each week, iPhone accessories and hobbyist parts like model railroad cars are the most common, Mr. Scott said, as is jewelry. “Drone parts are currently very popular, too,” he added.

Still, despite the production volume, and a few breakout objects that have sold in the thousands of units, most designers aren’t getting rich selling their products through Shapeways. The company declined to disclose combined earnings for its 15,000 shop owners.

Mr. Gant estimates that he has made about $800 so far through his Shapeways shop, but has spent about $300 on prototypes and printing his designs. As Mr. Scott noted, however, once a product has been designed and uploaded, there is potential for its designer to earn royalty-driven passive income, something Mr. Gant has experienced. “I will still, weekly, get a couple sales,” he said. “It still slowly trickles in. As I do more products, the trickle gets a little bigger.”

Mr. Scott said he is looking forward to the first Shapeways millionaire. Perhaps it will be him. In addition to promoting all the designers who use Shapeways, he is a designer himself. Bits to Atoms, a digital fabrication studio and consultancy he founded, has a Shapeways shop where you can buy the bronze skull ring that he wears on his right hand.