Plastic Injection Molding in Military Applications

Published on December 1, 2023

Military applications require tough materials that can withstand harsh conditions. Firearms and other weapons must be made from the strongest alloys, while the glass of first-person view cameras for military drones must also withstand harsh conditions. In such situations, plastic is commonly used, either to augment their durability or to tolerate environments that may corrode or otherwise debilitate equipment. Because of their properties, various plastics are found in the most complex military equipment, including anti-aircraft systems, fighter jets, main battle tanks, missiles, nuclear aircraft carriers, and submarines. The material is also used for bearings, brushing, and various other components within equipment for the military.

Equipment manufacturers that contract with the armed forces have also made increasing use of plastics in infantry kits and other equipment like clothing, electronics, and medical supplies. As plastic has become so important in the fabrication of military equipment, it’s no surprise that plastic injection molding has also become an integral technology used by military equipment manufacturers.

How Military Equipment Manufacturers Use Plastic Injection Molding 

Because plastic has become such a widely used material by the military, equipment manufacturers who make items for the defense industry have turned to injection molding technology to efficiently fabricate a wide range of devices at scale. As plastic is used for its properties in civilian applications, these same properties also make the material useful for the military. Equipment manufacturers make these items tougher for military applications, however, as they’re likely to be exposed to a range of environments that are found in deserts, forests, mountains, rivers, and elsewhere. They must deal with corrosive, dry, freezing, hot, muddy, wet, and other conditions. For this reason, the corrosion resistance, durability, and lightweight properties, among others, have made certain plastics with these properties ideal materials.

Benefits of Injection Molding for Military Applications

While there are many ways in which to fabricate plastic products, injection molding offers many advantages over other other processes. The fact that it’s incredibly cost-efficient at scale is why so many military equipment manufacturers utilize injection molding. Once a mold has been made, the costliest part of the process, hundreds of thousands or even millions of products, can be fabricated quickly. 

Plastic injection molding can be used for both tactical and specialized military equipment. Manufacturers use plastic for these applications because of its resistance to water, lighter weight and dielectric properties. Plastics are used for anything from high-precision components for weapons systems to simple plastic connectors, and the injection molding process makes it economical to produce these items uniformly at scale while also making them more dependable in the field.

An array of essential military items that utilize injection molding technology include:

  • Brackets, connectors, fasteners, and other components
  • Communications equipment like headsets and radios
  • Components in firearms, weapons systems, and other military hardware
  • Containers for food and water, like canteens
  • Firearm buttstocks, grips, handguards, frames, magazines, optics, recoil pads and triggers
  • Flashlights, shovels, and other tools
  • Implements on backpacks and kit bags
  • Parts for vehicles and weapons systems
  • Protective gear like helmets and tactical armor
  • Scopes for sniper rifles and other optical equipment

Plastic injection molding technology also allows manufacturers to utilize complicated designs for military-grade equipment, which helps ensure these devices survive combat conditions. It can also be used to mass-produce necessary kits for soldiers. Take a simple flashlight used in a battlefield setting, for example. It must be durable enough to withstand explosions and be lightweight and waterproof. On top of this, the battery must be able to hold a charge in the most demanding situations. With plastic injection molding, simple products like flashlights can be made inexpensively and quickly.

Plastic Properties Compared to Other Materials 

Though other materials offer properties that make them valuable for military equipment, manufacturers understand that for many items used by the armed forces, plastics prove to be an even better material. Plastic is corrosion-resistant, easier to work with, and inexpensive. Additionally, certain plastics have specialized capabilities that make them perfect for use in military equipment.

The most widely used plastics for military applications include: 

  • Polyamide (PA) 6: Also known as nylon 6, its chemical resistance, low friction coefficient, and strength make it good for making bushings, gears, rollers, and wheels economically.
  • Polyester (PL): Known for its resistance to chemicals and heat, as well as its rigidity, polyester is used to cost-effectively fabricate items like cams, electrical components, filters, and valves.
  • Polyetheretherketone (PEEK): A high-performance polymer, PEEK provides resistance to abrasion and chemicals as well as low moisture absorption and thermal stability, making it an excellent material for aircraft parts, electrical connectors, pump impellers, and seals.
  • Polyoxymethylene (POM): Also known as acetal, POM offers dimensional stability due to its rigidness, along with resistance to moisture and chemicals, so it works well for low-cost production of bearings, cams, gears, handles, plumbing components, rotors, and slide guides.
  • Polyphenylene sulphide (PPS): A highly performing plastic with considerable strength and resistance to heat, PPS is used for covers, components in fuel systems, shielding, and switches in harsher environments.
  • Polypropylene (PP): Highly resistant to chemicals and heat while also lightweight and tough, PP is used for inexpensively making military-grade connectors, containers, fasteners, straps, and ropes.  
  • Polyvinyl chloride (PVC): Flame-resistant, flexible, and tough, PVC is used for boot soles and electrical insulation due to its durability and low cost.
  • Thermoplastic elastomer (TPE): With decent thermal properties, flexibility, and material stability, TPE works well for boot soles, grips, handheld equipment, night vision gear, protective masks, and other military equipment, with its color-retention capabilities making it useful for camouflaging various combat kit.
  • Thermoplastic polyurethane (TPU): With its ability to withstand impact by effectively absorbing and dissipating energy, TPU works well for applications that include ballistics-resistant glass and military armor.

The diverse properties of each of these plastics mean they’re often used for different purposes, sometimes even as distinctive parts within the same piece of military equipment. By understanding the various properties of plastics, military equipment manufacturers can make items that tolerate harsh conditions on the battlefield and behind the lines. It’s these material properties that make plastic indispensable to the military, though their durability and lighter weight make them particularly useful for military applications.


Because plastics take decades to break down, their durability is ideal for military equipment. Manufacturers for the defense industry understand that this trait will ensure it survives under the most adverse conditions. Durability translates into dependability, so military gear often features plastic buckles, seals and other implements that go into the field. Plastic injection molding technology helps military gear resist corrosion and extreme temperatures. It also offers dielectric properties, so is often used as electrical insulation.


While metals and alloys might be tough and generally durable, plastics are significantly lighter in weight. This means small arms and light weaponry carried by infantry weigh significantly less, with grips, frames, stocks, and triggers made from lightweight plastics. The use of plastics in the US military began during World War 2. Invented in the mid-1930s, nylon was used for body armor, helmet liners, parachutes, ropes, and other equipment. Meanwhile, plexiglass was used for aircraft windows, with polymethyl methacrylate (Perspex) and polythene for insulating radar. With the increasing use of plastics in military equipment, manufacturers can make these items weigh less while ensuring they remain durable.

Advantages of Injection Molding Process for Military Equipment

Along with the valuable properties plastics provide for military equipment, manufacturers that utilize injection molding processes have significant advantages over those that don’t use the technology. The benefits of plastics as a material for the military become even more pronounced when looking at the techniques plastic injection molding brings to the table.

Faster Fabrication

It takes considerable time to melt down metals or alloys – or tempering glass – into military equipment. Manufacturers for the armed forces understand this, which is why many have incorporated plastics into their products for the defense industry. Injecting plastic resin into a mold is far more efficient than the methods used with other materials, allowing for quicker mass production of vital components. These faster turnaround times ensure that military personnel have what they need to conduct operations effectively.

More Design Options

Plastic resins can be made into almost any shape or size. As a result, plastic injection molding allows for innovative designs for a wide range of military equipment. Manufacturers also have a wide array of materials, each with useful properties. Design options can include over-molding, for example, a process where one plastic component is molded over another one, which can provide ergonomic benefits for specialized equipment. This process can produce more robust parts with added features, such as high resistance to impacts or vibrations.


Whatever the military equipment, manufacturers for the defense industry know that they need to make items for the armed forces out of the best possible material. Hundreds of billions of dollars annually go into purchasing and maintaining equipment for the US Department of Defense (DoD). While this is a considerable amount of money, the DoD, like any other government entity, looks to get the most bang for its buck.

Since plastics cost less than metals or their alloys and wood or glass, using plastics saves the DoD money. Plastic injection molding helps military equipment manufacturers produce items that perform as well or better than those made from alternative materials. Take decoys for military aircraft, for example, which are used to deceive enemy missiles. Being able to mass produce such essential yet easy-to-fabricate equipment reliably and repeatedly while keeping costs down facilitates a more agile military.

Spaulding Composites: Military Equipment Manufacturers

Spaulding Composites Inc. is committed not just to meeting but exceeding both expectations and requirements for the making of military equipment. Manufacturers that work with us include leaders in the aerospace and defense industry, including tier-one suppliers, military aircraft makers, and defense contractors. We also work with firearms manufacturers for injection molding various gun components. Spaulding additionally has wide-ranging experience working with providers of aircraft maintenance, repair services, and space launches, along with federal agencies. To learn more about our capabilities, contact the experts at Spaulding today.