Hard armor plates are designed to defeat rifle-caliber threats by using materials—primarily ceramics and polyethylene—that absorb and dissipate the energy of incoming projectiles. The manufacturing process involves precise material layup, high-pressure consolidation, and rigorous quality tracking at every stage. This page covers how these plates work at a material level and how they are produced, drawing primarily from T.REX ARMS’ in-depth visit to Hesco’s manufacturing facility in Aberdeen, Washington.
How Hard Armor Defeats Projectiles
All composite hard armor relies on some type of backing material—polyethylene (PE), aramid, or similar—to catch and absorb a bullet’s energy. Depending on the threat level, a ceramic strike face is bonded to the front of the backer.
When a round strikes a ceramic-faced plate, the ceramic begins breaking up the projectile and slowing it down. The initial layer of fibers behind the ceramic will break because the bullet is still traveling too fast, but as the round decelerates, successive fiber layers catch it. Each layer of fiber pulls and stretches slightly before breaking, progressively absorbing kinetic energy across the plate. This is how energy is distributed rather than concentrated at a single point.
For plates rated to stop armor-piercing threats (such as M2 AP), the ceramic component is essential because it must fracture and disrupt the hardened steel penetrator before the polyethylene backer can do its work. Pure polyethylene plates—without a ceramic strike face—can defeat softer projectiles like standard M80 ball and even M855A1, but they cannot reliably break up a hardened penetrator on their own.
Multi-Hit Degradation
Each successive hit on a plate degrades its ability to stop subsequent rounds. The fibers that absorbed energy from the first shot have already been pulled and broken, reducing the material available to catch the next projectile. This is why shot placement matters during certification testing: shots placed too close together will cause accelerated degradation because fibers displaced by the first impact are no longer available to support the second. Certification testing accounts for this by requiring minimum distances between shot locations.
Manufacturing Process
Hesco’s production line involves approximately eight distinct process steps to complete a single composite plate, beginning with raw material receiving and ending with labeled, serialized, packaged product.
Material Receiving and Inspection
Raw materials—ceramic tiles, rolled polyethylene goods, foams, and sheet materials—arrive at the facility and are inspected upon receipt. The polyethylene shield material is composed of layers of fibers (commonly described as similar to dental floss material). Suppliers provide inspection reports, and Hesco’s operators visually inspect each roll as it is unrolled on the ply cut table, cross-checking against supplier documentation.
Cutting (Gerber Machine)
Rolls of polyethylene are loaded onto a Gerber cutting machine. The correct file is loaded specifying the plate size (e.g., SAPI medium), and the machine cuts the material to the precise dimensions needed. After cutting, operators use a scale to check aerial density, confirming that the material has sufficient fiber content and adhesive before moving to the next stage.
Layup
Cut plies are assembled into a “layup”—a stack of polyethylene sheets at the correct ply count and weight for a given plate model. Each layup is weighed and marked with a work order number, plate number, model, and size. All lot information, weights, and material details are entered into a computer database for traceability.
Pressing (Consolidation)
Layups are placed into aluminum tooling and loaded into one of two hydraulic presses—an 800-ton or a 920-ton press. This consolidation step transforms a thick, flat stack of unconsolidated material into a much thinner, multi-curve plate. The extreme pressure bonds the fiber layers together into a rigid composite structure.
Ceramic Bonding (Oven)
If the plate requires a ceramic strike face, the pressed polyethylene backer is taken to the oven assembly table. A ceramic tile is placed on the front and bonded to the backer through an oven cycle, producing the finished ballistic core: ceramic in front, polyethylene backer behind.
Water Jet Trimming
Plates that come out of the press slightly oversized are trimmed to exact final dimensions on a water jet cutter. This applies to both pure PE plates and ceramic-composite backers.
Wrapping and Finishing
The trimmed ballistic core moves to the wrap station, where back foam, edge foam, and edge nylon are applied. The plate is then wrapped in a nylon cover, giving it the finished appearance users are familiar with. All wrapping details are logged into the traceability database.
Labeling, Serialization, and Packaging
Each finished plate receives a label with a serial number tied to the work order, which links back to every material lot used in that specific plate. Plates pass through a final oven step, are packaged by order, and each box is marked and weighed. Serial numbers per box are recorded on pallet orders so that if a shipment is lost or stolen, the exact plates involved can be identified.
Quality Control Throughout Production
Every work cell in the manufacturing process has what Hesco calls “critical to quality” parameters. Before a plate can move from one station to the next, operators must measure defined attributes, record them, and enter data into a centralized database. This system ensures that each plate is built within specification at every stage—not just inspected at the end of the line.
Hesco also operates a ballistic deconstruction lab where plates returned from third-party test labs are torn apart and inspected. This post-test analysis identifies areas for product improvement based on real ballistic performance data.