3D printer plastic, commonly in the form of filament, is primarily made through a process called compounding, which involves several key steps to transform raw plastic into a usable printing material.
The journey of 3D printer plastic filament begins with raw plastic resin in the form of small pellets. This raw material is the base polymer that will form the core of the filament.
The Compounding Process: Turning Pellets into Filament
The production of 3D printing filament is known as compounding. It's a manufacturing process that carefully controls the plastic's composition and physical characteristics.
Here are the main steps involved:
1. Starting with Raw Pellets
The foundation of 3D printer filament is raw plastic resin, typically supplied in small, uniform pellets. These pellets are the pure form of the polymer, such as PLA, ABS, PETG, Nylon, or others.
2. Mixing with Additives
To achieve specific properties required for 3D printing and the final printed object, the raw plastic pellets are mixed with various additives. These additives can include:
- Colorants: To give the filament its desired color.
- Plasticizers: To increase flexibility.
- Fillers: Such as carbon fiber, glass fiber, metal powder, or wood particles, to enhance strength, stiffness, or create unique textures.
- UV Stabilizers: To prevent degradation from sunlight.
- Impact Modifiers: To make the plastic less brittle.
This mixing step is crucial for tailoring the filament's performance characteristics, from its melting temperature and flow rate to its mechanical strength and appearance.
3. Drying the Mixture
Before melting and extrusion, the mixture of plastic pellets and additives is carefully dried. Many common 3D printing plastics are hygroscopic, meaning they absorb moisture from the air. Excess moisture can cause issues during extrusion and printing, such as bubbles, inconsistent diameter, and degraded material properties. Drying ensures the plastic is at the optimal moisture level for the next stage.
4. Extrusion and Sizing
The dried plastic mixture is fed into an extruder. Here, it's heated to a molten state and pushed through a precisely shaped nozzle (die) to form a continuous strand. The diameter of this strand is critical for 3D printing compatibility. The reference highlights that the mixture is extruded to a desired width, usually 1.75 mm or 2.85 mm, which are the standard diameters for most FDM 3D printers. The extruded strand is cooled rapidly to solidify while maintaining its consistent diameter.
5. Winding onto a Spool
Finally, the cooled and solidified filament strand is carefully wound onto a spool. The winding process must maintain tension and prevent tangling, ensuring the filament can be fed smoothly into a 3D printer. Quality control checks are performed during and after winding to verify diameter consistency, roundness, and overall quality.
This multi-step process transforms basic plastic resin into the high-quality filament required for reliable and successful 3D printing.
