The moisture content of PLA pellets has a significant impact on the quality of PLA 3D printing filament during production. PLA is a hygroscopic material, meaning it easily absorbs moisture from the surrounding environment. If the pellets contain excessive moisture before extrusion, it can cause several processing and quality problems.
Below is a professional explanation from a manufacturing perspective.
1. Influence on Melt Extrusion Stability
During the production of PLA filament, the material is typically melted and extruded at temperatures around 170–210°C. If PLA pellets contain moisture, the water will rapidly vaporize at high temperature, which can lead to:
• Formation of bubbles in the melt
• Micro-voids or pores inside the filament
• Unstable extrusion flow
These issues directly affect the diameter consistency of the filament, which is critical for standard sizes such as 1.75 mm or 2.85 mm.
2. Material Degradation (Hydrolytic Degradation)
PLA is sensitive to hydrolysis when exposed to both heat and moisture. During extrusion, moisture can break down the polymer chains, resulting in:
• Reduced molecular weight
• Lower melt viscosity
• Decreased mechanical strength
As a result, the produced filament may become:
• More brittle
• Prone to breaking during printing
• Less durable in printed parts
3. Reduced Surface Quality
If the moisture content of PLA pellets is too high, the extruded filament may show visible defects such as:
• Rough surface texture
• Tiny bubbles
• Silver streaks
• Poor surface gloss
These defects reduce both the appearance and perceived quality of the filament.
4. Negative Impact on 3D Printing Performance
Moist PLA filament can also create problems during the printing process, including:
• Popping or crackling sounds from the nozzle
• Inconsistent extrusion
• Weak layer adhesion
• Small holes or rough surfaces on printed parts
These issues ultimately result in lower print quality, reduced strength, and poor dimensional accuracy.
