How mattresses are made: An inside look at an American mattress factory

Our mattress expert toured the 3Z Brands factory in Arizona. He went behind the scenes of the mattress-making process, from pouring foam to boxing.

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Many steps go into making the modern mattress. Most include a complex combination of foam, metal, and fabric assembled just right to ensure you sleep great. We recently got an in-depth look at how mattresses were made on a tour of the 3Z Brands factory in Glendale, Arizona. This 650,000-square-foot vertically integrated manufacturing plant enables 3Z,  to oversee the entire mattress-making process from materials to packaging. 

The 3Z Brands portfolio includes Helix, Leesa, Brooklyn Bedding, Nolah, Bear, and Birch mattresses and specializes in bed-in-a-box mattresses that ship free straight to your door. Several of these mattresses are featured in our best mattress guides. 3Z manufactures about 2,200 mattresses daily in its factory and has the capacity to make 4,000. With the extra capacity, 3Z Brands also makes mattresses for other companies, including Nectar, GhostBed, Allswell, and Nest Bedding.

Here's a detailed account of our tour of the 3Z Brands factory and a look into how mattresses are made, from sewing to packaging. 

Making the foam

Before 3Z Brands can assemble their mattresses, they must fabricate the various parts. As of 2023, 3Z makes all of its foams in-house, meaning they control the entire foam-making process from recipe development to cutting. Foam is one of the most important parts; it takes the longest to prepare. Unfortunately, the only area we couldn't photograph or record was one of my favorite parts to watch: the foam pouring. This was done to protect trade secrets.

Since I can't lean on the "thousand words" of a photo, I'll do my best to describe what I saw. The foam pouring machine is roughly 40 feet long, 10 feet wide, and rises 20 feet. The foam's chemicals are mixed before entering a long metal bar. The concoction is forced through hundreds of holes in the bar to get more air into the foam. 

As the foam sets, a plastic-covered conveyer belt slowly moves the massive foam block forward. The foam is poured into 100-foot-long blocks about 4 feet deep and maybe 7 feet wide. A huge elevator moves the blocks to a spot in the warehouse for curing in the dry Arizona heat for 24 to 72 hours. 

Pouring foam is dangerous, so most companies outsource this step. If you get the formula wrong, the internal temperature of the foam block will rise too high and could start a fire. The foam temperature at the 3Z factory reaches 280 degrees Fahrenheit.

Once it has cured long enough, it's time to cut the foam blocks down to size. First, it's cut vertically to match the dimensions of a mattress, as shown above. Then, it's cut horizontally using a machine I like to call "the Decapitator."

At this point, the foam layers are ready for the mattress. Leftover scraps are put to good use, such as filling pillows.

Constructing the pocket coils

Pocket springs, or coils, are a signature feature of hybrid mattresses. They provide durability, support, and airflow. The springs arrive at the factory as a giant coil. The end of the coil is fed into a machine that turns the long steel "thread" into smaller springs appropriate for a mattress. 

The spring assembly line is wrapped in fabric to make individual "pockets." Unlike traditional spring mattresses, the springs in hybrids are usually separated to assist with motion isolation.

Narrower, denser coils are used for the edges to help with edge support. 

The springs are put together in a single layer to be layered and assembled into a mattress.

Sewing the cover

Between the quilting, borders, and handles, a lot of work goes into sewing a mattress cover, and each step requires a specialized machine. 3Z employs a team of mechanics to maintain the equipment and ensure everything keeps running smoothly.

The machine below just makes the mattress borders. It features 65 sewing needles and makes eight border rolls at a time.

Some borders feature vertical stitching, which requires a whole other machine.

And you better believe there's a separate device for adhering handles to the borders. 

The same machine that creates the borders is also used to quilt and combine the mattress top, which combines fabric, foam, and a flame-retardant layer. The manufacturer can program the design and materials based on their desired model and size.

During the tour, my editor tried serging together the mattress's top layers on an air hockey-like table. She did a good job, but her effort didn't quite pass quality control. Keep at it, Jaclyn!

Assembling the mattress

Once the foam, pocket springs, and mattress covers are ready, it's time to assemble all the components together. First, the layers are glued together to keep them in place. Above, workers put together zoned-support mattresses, which must be assembled by hand. You can also see mattresses glued together by a machine on the conveyor belt behind them.

Once the layers are assembled, the cover is stapled in place, and the mattress starts to resemble its final product.

Boxing it up

Ever wonder how they get a mattress into those mini fridge-sized boxes? I always have. You may not be surprised that they rely on a specialized machine. The fully assembled mattress is crushed flat and vacuum-sealed in plastic. Then, it's folded, rolled, wrapped in more plastic, and stuffed in a box to be delivered to your door. Here's the whole process at four times the normal speed:

Mattresses can't stay in the box forever, so most 3Z mattresses are made to order. They should be unboxed within 30 days; any longer than that could compromise their ability to expand. Manufacturers must nail the delicate balance of producing enough beds to meet demand while ensuring they don't stay on shelves for long.

Testing and constant modifications

With hundreds of mattress brands competing for your dollar, manufacturers must stay ahead of the trends and incorporate the latest technology in their mattresses. When we asked 3Z CEO John Merwin and Nolah Mattress CEO Stephen Light about the mattress they're sleeping on, the answers were related to experimenting with the next product in development, like an expansion into a largely untapped mattress category: the Alaskan King, a 9 foot by 9 foot mattress. 3Z Brands employs a foam engineer with a room full of reference samples for experimenting with new foam variations. The factory also featured an area where you can design your own mattress using the materials made at the facility to help with product development.

What stood out to me were all the companies worldwide that manufacture mattress-making and testing machines. The machine below simulates years of sleeping on the mattress. It's used to quickly assess durability and determine the warranty length 3Z will offer.

The bottom line

The next time you look at a mattress, think of all the work that went into it. Maybe, take a closer look at the materials and their origin. As you're drifting off to sleep, think of the hundreds of people who worked together to ensure you get that good night's sleep. It's pretty astounding. Sweet dreams!