Injection Molding for Defense Applications

Last updated on July 18th, 2025 at 12:06 pm

Plastic injection molding is a manufacturing process that involves melting and injecting plastic resin into a mold cavity under pressure until it solidifies and cools. The result forms a product or component shaped like the mold. In fact, most mass-produced plastic parts are made via injection molding. For defense applications, this manufacturing method has enormous benefits, as it not only allows for production at scale but also enables defense contractors to meet the stringent tolerances often required for military equipment.

There are many other reasons why those who supply military gear often prefer methods like plastic injection molding. Military components must be sufficiently robust to withstand battlefield and other inhospitable conditions. Plastics don’t conduct electricity or heat, which makes them safer in certain circumstances, while their lighter weight also makes them preferable for kits that soldiers must carry. For manufacturers that produce a wide range of products or parts for the military, injection molding is a key fabrication method.

Critical Role of Injection Molding in Defense Applications

Often, greater strength and impact resistance can be achieved for items fashioned via injection molding. For military components, the injection molding process enables anything from rugged exterior parts that can withstand harsh conditions to complex internal devices that support cutting-edge technologies. For companies building products for military defense, injection molding has demonstrated its ability to work with a plethora of different materials and a diversity of components. 

Benefits of plastic injection molding for military components and products include: 

• Corrosion-resistance: Can withstand environmental wear that corrodes other materials.
• Cost-efficiency: Cheaper than metals or many other materials, injection molding enables militaries to get more for their money.
• Customizability: Specific properties can be engineered to better suit certain tactical situations.
• Durability: Able to withstand harsh conditions, including temperature extremes from freezing to high heat environments and other poor weather conditions.
• Lightweight: Generally having high strength-to-weight ratios.
• Mass production: Injection molding for military components and other products allows high-capacity fabrication of intricate yet identical items. 
• Non-conductive: Since plastics don’t conduct electricity, they’re more desirable for applications where gear will be exposed to electricity.
• Robustness: Whether small or large, plastic injection molding for military components produces items that are more robust.
• Accuracy: With injection molding for military components, greater accuracy can be achieved to produce tighter tolerances.
• Chemical resistance: Certain conditions in the field require materials that resist chemical corrosion and wear, which plastics provide.

Lighter weight military gear and equipment have become increasingly necessary for the mobility required in modern battlefield techniques such as active defense. Injection molding for military components better enables gear to be made through repeatable processes, which are necessary for high-capacity production. Defense injection molding can even incorporate designs made from multiple materials, with these components presenting the best properties of metals, plastics or other materials included in the composite.

Injection Molding: For Military Components & Other Defense Applications 

For many types of items made for defense, injection molding of plastics is widely used. Applications that involve plastic injection molding for military components and equipment span a range of applications, from communications devices to components for military vehicles.

Communications Equipment

Keeping communications operational during military missions is integral to their success. Personnel in the field need to communicate effectively over long distances, with messages relayed accurately. For such applications in defense, injection molding provides a means for quickly producing complex components for communications equipment, which is essential for most military undertakings. Components are usually made from rugged types of plastic and are often found in tactical headsets, radios, casings for these devices, and other communications gear used for defense. Injection molding ensures these parts are manufactured accurately and quickly at scale, including waterproof casings to protect the electronics within.

Firearms 

A basic item for defense, injection molding for military components found in firearms enables large numbers of identical items to be made. These include butt stocks, grips, handguards, holsters, magazines, optics and other firearm components, which can be made with high precision. Various types of plastics are used to produce firearms due to their lighter weight, corrosion resistance and cost-effectiveness.

Kit Bags

Injection molding for military components on kit bags may seem irrelevant in the larger scheme of defense. Injection molding works well for producing robust, long-lasting connectors, fasteners and hooks attached to these kit bags. As kit bags often need to handle heavy weights, these must be extraordinarily durable.

Optical Systems

This includes flashlights, night vision goggles and scopes, along with all their sensitive parts. Injection molding for military components in optical systems uses either transparent or opaque resins, both of which are useful in optics for defense. Injection molding can produce anything from clear plastic through which light easily travels or eyes can see, to types that light can’t penetrate as protective coverings for vital parts of the system.

Military Containers

Robust yet lightweight, plastic makes good material for food and water containers used in defense. Injection molding allows manufacturers to make these items in bulk, plus the plastic used for these types of items can be more easily sanitized so that it can be reused repeatedly.  

Protective Gear

Plastic protective gear that helps reduce impacts or protect a soldier’s torso or head like body armor plates and helmets are items that every soldier needs for defense. Injection molding for military components that provide protection is often made with hard plastics that are often more durable than metal alloys yet lighter weight. Additionally, certain plastics can be produced with multiple pigments required for camouflage.

Vehicle Components

As with civilian vehicles, for those used for purposes of defense, injection molding of plastic components is commonly used. With the wider automotive industry, more and more vehicle parts are being constructed from plastic today, thanks to its durability, flexibility and the ease of making large quantities of parts that are identical in shape, size and performance. Military vehicles must keep working in extreme conditions and on rough terrain, so durability and high performance are vital for their internal plastic parts.

Best Materials for Defense Injection Molding 

Injection molding for military components allows for the use of a wide array of plastic resins. Defense injection molding must consider applications, budgets, designs, manufacturability and other aspects of production. The best plastic resin to use depends on these qualities, along with their material properties.

Plastics used in injection molding for military components include: 

• Acrylic (PMMA – polymethyl methacrylate): Known also by its tradename Plexiglas®, the optical clarity and impact resistance presented by this thermoplastic makes it useful for canopies of aircraft and lenses in military-grade optical equipment; acrylic composites are also used in the fabrication of enclosures for armored vehicles, as well as blast-resistant and bulletproof windows for such.
• Bismaleimide (BMI) resins: Known as high performing thermosetting polymers, they are exceptionally heat resistant and able to withstand other extremes; due to their other unique mechanical properties, BMI resins are used in injection molding for military components in missiles and radar systems.
• Epoxy resins: These thermosetting plastic resins are chemical and corrosion resistant, lightweight and incredibly strong; composites that include epoxy resins are used in aircraft, armored vehicles, electronic systems and protective coatings.
• Nylon (PA – polyamide): A thermoplastic that’s durable, lightweight and resistant to wear, nylon is well-suited to injection molding for military components in weapons, and because of its self-lubricating properties also as gears in equipment used by soldiers in the field; nylon webbing is also used for tactical accessories and gear like chin straps for helmets, harnesses, slings, straps and weapon retention systems.
• Phenolic resins: Resistant to fire and impacts, the mechanical strength and thermal stability of these resins make them perform reliably in battlefield conditions as protective housings and electrical insulators; composites that include phenolic resins are used for ablative shielding, lightweight armor and missile components.
• Polycarbonate (PC): Injection molding for military components and products often use this thermoplastic works well in molds and remains stable at high temperatures; because of its transparency and impact resistance, it’s used for night vision goggles, helmets and ballistic glass.
• Polyetheretherketone (PEEK): A high-performance thermoplastic able to withstand extremes in temperatures, PEEK is also chemical-resistant and dimensionally stable, among other material properties; PEEK is used in injection molding for military components found in weapons systems, electronics and aerospace applications.
• Polyetherimide (PEI): Often referred to by its trademarked name ULTEM®, PEI is a low weight and heat-resistant thermoplastic that can replace heavier metals in aerospace applications to ensure greater efficiency while it also contributes to reducing radar signatures in stealth aircraft; PEI also provides excellent heat resistant and insulation properties, making it useful for avionics and radar systems.
• Polypropylene (PP): Low weight, chemical resistant and very durable, this versatile thermoplastic is often used for defense-related injection molding; PP is often used for chair armrests, interior assemblies, paneling seatbacks and other nonstructural elements of aircraft, as well as in protective gear and storage cases.  

Each of these materials offer advantages when injection molding for military components. Besides these plastics used in defense, injection molding can also be used to make composites, many of which use thermosetting polymers.

Plastics for Defense: Injection Molding of Thermosetting Polymers & Composites

Thermoset injection molding for military components produces highly durable, heat-resistant, and chemically stable materials. Unlike thermoplastics, thermoset plastics retain their shape and properties under the harshest conditions after curing, making them particularly useful for military-grade production. Often, these thermosetting polymers are made into composites containing multiple materials.

Thermoset injection molding for military components offers the following advantages: 

• Chemical resistance: Thermosets won’t readily break down when exposed to chemicals, along with fuels and oils, making them ideal for injection molding of military components used in fuel systems for military vehicles and other items that exposed to harsh chemicals.
• Corrosion resistance: Aircraft components, electronics, protective gear and other equipment used by the military benefit from thermosets’ resistance to corrosion.
• Dielectric properties: This property makes thermosets ideal for communications equipment, electrical insulation, housings for electronic devices, radar systems and other equipment that needs to endure electricity.
• Dimensional stability: When used in injection molding for military components or equipment, thermosets and thermoset-based composites under intense stress do better at maintaining their structural integrity as they don’t warp over time.
• Heat resistance: Able to withstand high heat without becoming more pliable, thermosets ensure injection molded components remain stable in military aircraft, vehicles, weapons systems and other military equipment.
• Strength: Capable of handling significant mechanical stress before they fail, thermosets are useful for military components, including ballistic armor, vehicle components, and protective enclosures.
• Toughness: It takes a lot of energy to fracture thermosets, so injection molding for military components made from these materials allows them to withstand impacts better.

These advantages make thermoset injection molding for military components a key means for fabricating aircraft parts, electronics, military vehicles, naval vessels, and other defense equipment. Injection molding of thermosets offers defense manufacturers a way to make reliable and long-lasting military-grade equipment for almost any application.  

Spaulding Composites: Defense Injection Molding for Military Components

Spaulding Composites Inc. can supply defense contractors with injection molding for military components and military equipment of all sorts. We currently work with a variety of manufacturers and suppliers, offering injection molding for military components and equipment. These include companies involved in aerospace companies, aircraft maintenance and repair vendors, federal agencies, firearm makers, space launch operators and other service providers. To learn more about our defense injection molding capabilities, contact the experts at Spaulding today.