Many players have probably heard numerous technical terms related to PLA 3D printing filaments, and some may not fully understand them. Today, let's try to explain a few: filament diameter, diameter tolerance, roundness, melting point, softening temperature, density, melt flow index, moisture content, hydrolysis, brittle fracture... Wait.
Specification wire diameter
The 3D printing consumables are produced with a fixed thickness at the factory. The mainstream sizes on the market are 1.75mm and 2.85mm. These are the matching standards for the printer's feed system, gear engagement, and nozzle discharge. Uniform specifications are necessary to be compatible with the vast majority of desktop FDM printers, ensuring smooth feeding without jamming.
2. Wire Diameter Tolerance
The allowable deviation range between the actual thickness of the consumable material and the standard wire diameter. The reference value is +/-0.03mm. High-quality PLA strictly controls the positive and negative errors. The smaller the error, the more uniform the extruded output will be, without sudden thickening or thinning, effectively avoiding problems such as printing breakage, nozzle blockage, layer lines, and overflow.
3. Wire diameter roundness
The degree of roundness and regularity of the cross-section of the consumable material. Normal consumables are in a standard circular shape; if the roundness is poor, there will be flat wires or elliptical wires, which will cause the feeding to slip, unstable extrusion, more surface defects on the printed model, and affect the forming accuracy.
4. Melting Point
The temperature at which PLA particles completely melt and turn into a flowing melt. The melting point of PLA is relatively mild, and the printing temperature is low. Generally, a temperature range of 190–210℃ is sufficient for normal printing. It has low energy consumption and quick heating, which is also the main reason why it is the most friendly core for beginners.
5. Softening Temperature
The critical temperature at which PLA begins to soften and lose its rigidity (commonly referred to as Vicat softening temperature). The softening temperature of PLA is around 55℃. In fact, many printing jams occur because the dust on the cooling fan of the nozzle is too much, resulting in insufficient heat dissipation efficiency, causing the PLA in the tube to soften and unable to be extruded by the gear drive, leading to a failure to print.
6. Density
The weight per unit volume of the consumables, density: 1.24 g/cm³. The density is uniform and stable, indicating that the raw material formula is pure, the mixing is uniform, the printing shrinkage rate is consistent, the model is less likely to curl or crack, the weight and texture of the finished product are uniform, and the quality of each batch is more stable.
7. Melt Index
This is an indicator that measures the speed of PLA's flow after it melts at high temperatures. An appropriate index ensures smooth melt flow, easy extrusion, less filament extrusion, good detail reproduction; an excessively high or low index will result in easy run-off due to excessive fluidity or easy material jamming and poor inter-layer adhesion.
8. Moisture Content
The moisture content remaining inside the consumables, usually 0.5%. Although PLA is not prone to absorbing moisture, it still absorbs moisture over a long period of storage. Excessive moisture content can cause bubbles, spots, and surface blemishes during high-temperature printing, seriously affecting the appearance and structural strength of the model.
9. Hydrolysis
This is a phenomenon where consumables are exposed to moisture and a humid environment over a long period of time, causing the material molecules to be decomposed and damaged by the water. When stored in high humidity conditions and not dried for a long time, PLA will undergo slow hydrolysis. The internal structure of the material becomes looser, and the overall toughness decreases, accelerating the aging and deterioration of the consumables.
10. Brittle fracture
This is a phenomenon where PLA consumables are prone to breakage and lack sufficient toughness. It is usually caused by impure raw materials, water decomposition and moisture absorption during storage, excessive aging due to prolonged exposure to air, and excessive cooling. The symptoms include easy breakage when bent, fragility of the printed model, and cracking and damage at the stressed areas.
Overall: The raw material parameters determine the printing limit. Stable filament diameter, reasonable physical property indicators, and strict control of moisture content are the core key factors for good PLA consumables printing, less breakage, and durable finished products.
