3D printing filament is a thermoplastic material supplied in continuous lengths, designed for use in fused deposition modeling (FDM) and fused filament fabrication (FFF) 3D printers. The filament is fed through a heated extruder nozzle, where it melts and is deposited layer‑by‑layer to build three‑dimensional objects.
Materials
Common filament materials include:
- Polylactic acid (PLA) – a biodegradable polymer derived from renewable resources such as corn starch. It is noted for low printing temperatures (180–220 °C) and minimal warping.
- Acrylonitrile butadiene styrene (ABS) – a petroleum‑based polymer with higher strength and heat resistance, typically printed at 220–260 °C. ABS can emit volatile organic compounds (VOCs) during printing.
- Polyethylene terephthalate glycol‑modified (PETG) – combines the ease of printing of PLA with the durability of ABS; printed at 220–250 °C.
- Nylon (polyamide) – known for high tensile strength, flexibility, and chemical resistance; requires higher printing temperatures (240–260 °C) and often a heated build chamber.
- Polycarbonate (PC) – offers high impact resistance and heat resistance; printing temperatures range from 260–310 °C.
- Flexible filaments – such as thermoplastic polyurethane (TPU) and thermoplastic elastomer (TPE), characterized by low shore hardness and high elongation at break.
Specialty filaments include metal‑filled, wood‑filled, carbon‑fiber‑reinforced, and high‑temperature engineering polymers. These variants incorporate additives to impart specific mechanical, aesthetic, or functional properties.
Dimensions
Filament is produced in standardized diameters, most commonly 1.75 mm and 2.85 mm (often marketed as 3 mm). The choice of diameter affects extrusion consistency, feed rates, and printer compatibility.
Mechanical properties
Mechanical performance varies with material composition, printing parameters, and post‑processing. Typical properties are reported as follows (values approximate and dependent on printing conditions):
| Material | Tensile Strength (MPa) | Flexural Modulus (GPa) | Typical Printing Temp (°C) |
|---|---|---|---|
| PLA | 50–70 | 3.5–4.0 | 180–220 |
| ABS | 30–50 | 2.0–2.5 | 220–260 |
| PETG | 45–55 | 2.0–2.5 | 220–250 |
| Nylon | 70–90 | 2.5–3.0 | 240–260 |
| PC | 60–70 | 2.2–2.4 | 260–310 |
Industry standards and specifications
Manufacturers may adhere to standards such as:
- ASTM D638 – standard test method for tensile properties of plastics.
- ISO/ASTM 52900 – terminology for additive manufacturing processes, classifying FDM/FFF as “material extrusion.”
- UL 94 – flammability rating for polymeric materials, relevant for safety‑critical applications.
Environmental considerations
PLA is marketed as biodegradable under industrial composting conditions, though its degradation rate in ambient environments is slow. ABS and other petroleum‑based filaments are non‑biodegradable and may release ultrafine particles (UFPs) and VOCs during printing. Recycling programs for spent filament and failed prints exist, but the recyclability of multi‑material or composite filaments is limited.
Applications
3D printing filament is employed across multiple sectors, including:
- Prototyping – rapid iteration of product concepts.
- Education – hands‑on learning in engineering, design, and STEM curricula.
- Medical – production of anatomical models, surgical guides, and, where biocompatible filaments are approved, custom orthotic devices.
- Aerospace and automotive – fabrication of functional prototypes and low‑volume tooling components.
- Consumer goods – custom accessories, decorative items, and hobbyist projects.
Processing considerations
Successful printing depends on variables such as nozzle temperature, bed temperature, print speed, cooling airflow, and filament moisture content. Many filaments are hygroscopic; excess moisture can cause bubbling, stringing, and diminished mechanical properties. Desiccant storage or filament dryers are commonly used to mitigate moisture absorption.
Safety
When printing with heated filaments, users should ensure adequate ventilation, especially for materials that emit VOCs (e.g., ABS, PC). Personal protective equipment (PPE) such as respirators may be recommended in poorly ventilated settings. Thermal runaway protection is a safety feature in many modern printers to prevent uncontrolled temperature increases.
