Almost every plastic part you touch daily is made by injection molding. Common examples include: plastic syringes, toothbrush handles, phone cases, car dashboard switches, LEGO bricks, bottle caps, electrical connectors, and food container lids. Injection molding produces parts ranging from tiny medical components weighing fractions of a gram to large automotive bumpers weighing several kilograms — all with the same fundamental process.
Everyday Examples of Injection Molding
| Product | Material | Why Injection Molded |
|---|---|---|
| Toothbrush handle | PP + TPE (2K) | Complex ergonomic shape; soft-grip overmould |
| Medical syringe barrel | PP or PS | Precision bore; transparent; sterile; high volume |
| Phone case | TPU or PC/ABS | Exact fit to phone geometry; drop protection |
| Car dashboard switches | ABS + PC | Complex shape; snap fits; back-lit symbols |
| Bottle caps | PP or PE | Very high volume; thread precision; food-safe |
| LEGO bricks | ABS | ±0.002mm tolerance; snap-fit consistency across billions |
| Electrical connector housing | PA66 or LCP | Fine pin geometry; heat resistance; dimensional precision |
| Food storage container | PP | Thin wall; living hinge; microwave-safe material |
| IV drip chamber | PP or PVC | Medical-grade; transparent; sterile |
| Power tool housing | PA or ABS | Impact resistance; complex shape; ergonomic grip |
Automotive Injection Molding Examples
The automotive industry is the largest consumer of injection molded parts. A typical modern vehicle contains 1,500–2,000 individual injection molded plastic components:
- Interior: Dashboard substrate (PP-TD20), instrument panel (PC/ABS), door panel trim (PP), centre console (ABS), pillar trims (PP), air vents (ABS), seat components (PA)
- Exterior: Front and rear bumpers (TPO/PP-EPDM), door mirror housings (ABS), wheel arch liners (PP), grille inserts (ABS or PP)
- Under-hood: Air intake manifold (PA66-GF30), engine cover (PA or PP-GF), coolant reservoir (PP), battery housing (PP-GF)
- Electrical: ECU connector housings (PA66), fuse box covers (PP), wire harness grommets (TPE), sensor housings (PA or PBT)
Medical Device Injection Molding Examples
- Disposables: Syringes (PP/PS), blood collection tubes (PET), IV connectors (PP), catheter hubs (ABS/PP), pipette tips (PP)
- Diagnostic devices: Blood glucose meter housings (ABS), lateral flow test cassettes (ABS/PS), microfluidic chips (COC/COP)
- Surgical instruments: Retractor handles (PC), clip applier components (PA), endoscope housings (PC)
- Drug delivery: Inhaler components (ABS/PP), auto-injector housings (ABS), prefilled syringe components (COP/COC)
Consumer Electronics Injection Molding Examples
- Mobile devices: Phone cases (TPU/PC), tablet bezels (PC/ABS), earphone housings (ABS), charging connector covers (TPU)
- Computers: Laptop bezels (PC/ABS), keyboard keycaps (ABS), mouse shells (ABS), USB connector housings (PA/LCP)
- Home appliances: Washing machine control panels (ABS), refrigerator door liners (ABS/HIPS), vacuum cleaner housings (ABS/PC)
- Wearables: Smartwatch cases (PC/ABS), fitness tracker bands (TPU), hearing aid shells (acrylic/ABS)
Surprising Examples of Injection Molding
- LEGO bricks: Manufactured to ±0.002mm tolerance in ABS — among the tightest tolerances in high-volume consumer injection molding. A brick made in 1963 still fits a brick made today
- Optical lenses: Camera lens elements, reading glasses, and LED secondary optics are injection molded in PMMA or polycarbonate to optical-grade surface finish (Ra < 0.01μm)
- Artificial Christmas trees: Each branch tip is an individual injection molded PVC or PE component — a single large tree may contain thousands of individually molded parts
- Single-use cutlery: PS or PP forks, knives, and spoons are among the highest-volume injection molded items — billions produced monthly worldwide at cycle times under 5 seconds
- Spacecraft components: PEEK and high-performance polymer injection molded components are used in satellites, spacecraft, and aerospace applications requiring extreme temperature and radiation resistance
What Is NOT Made by Injection Molding?
| Product | Process Used | Why Not Injection Molding |
|---|---|---|
| PET water bottles | Injection stretch blow molding | Hollow shape requires blow molding |
| Plastic bags and film | Blown film extrusion | Continuous sheet/film process |
| PVC pipes | Extrusion | Continuous profile process |
| Large fuel tanks | Blow molding or rotomolding | Hollow; too large for injection |
| Rubber O-rings | Compression or transfer molding | Thermoset rubber requires different process |
| Carbon fibre parts | Compression molding / RTM | Thermoset composite requires different process |
What is the most common injection molded product?
Plastic bottle caps and closures are arguably the most commonly injection molded product by quantity — billions are produced every day globally. By value, automotive parts represent the largest category. By variety, consumer electronics housings and connectors have the widest diversity of injection molded components.
Are LEGO bricks really injection molded?
Yes — every LEGO brick is injection molded in ABS plastic to tolerances of ±0.002mm. The LEGO Group produces approximately 400 million LEGO elements per day across its manufacturing facilities. The precision and consistency required for LEGO bricks to snap-fit correctly across 60+ years of production is a benchmark for injection molding quality.
Can glass be injection molded?
No — glass is not thermoplastic and cannot be processed by injection molding. However, optical-grade plastics like PMMA (acrylic) and polycarbonate (PC) can be injection molded to produce transparent parts that substitute for glass in many applications, including lenses and display covers.
What is the largest injection molded part?
Some of the largest injection molded parts include automotive bumper fascias (up to ~2.5m wide) and large industrial enclosures. These require injection machines with clamping forces of 3,000–9,000 tonnes. Parts much larger than this are typically made by rotational molding or blow molding.
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