Study Reveals How Layer Height Filament Color Affect 3dprinted PLA

Imagine using the same 3D printer with identical PLA material, yet producing parts with dramatically different performance characteristics simply by altering the layer height or switching filament colors. This perplexing phenomenon is not uncommon in Fused Deposition Modeling (FDM) applications. This article examines how these seemingly minor factors—layer height and filament color—can significantly influence the mechanical properties and dimensional accuracy of polylactic acid (PLA) prints, providing insights for optimizing 3D printing parameters.

Additive Manufacturing (AM), commonly known as 3D printing, is rapidly transforming industrial production. Heralded as a frontier technology of the "Fourth Industrial Revolution," its core principle involves constructing three-dimensional objects through successive material deposition. Compared to conventional manufacturing methods like machining or casting, 3D printing offers distinct advantages:

• Cost and time efficiency: Eliminating the need for tooling enables direct part production from CAD models, significantly reducing costs and lead times.
• Geometric complexity: Facilitates fabrication of intricate designs unachievable through traditional methods.
• Rapid prototyping to production: Seamlessly transitions from concept validation to final product manufacturing.
• Material conservation: Builds components layer-by-layer, minimizing material waste.

These benefits have spurred widespread adoption across industrial, educational, medical, and consumer sectors, with market projections indicating sustained growth.

Among various 3D printing techniques, FDM stands out for its affordability and operational simplicity. The process feeds thermoplastic filament through a heated nozzle, depositing molten material in precise layers to form three-dimensional objects. PLA remains the most prevalent FDM material due to its low melting point, ease of printing, minimal toxicity, and renewable origins. Available in multiple colors, PLA serves diverse applications.

As 3D printing transitions from prototyping to manufacturing, parameter optimization becomes critical. Final product quality—encompassing dimensional accuracy, deformation, mass deviation, porosity, and surface texture—depends on numerous interrelated process variables. Unlike conventional manufacturing, FDM part strength is determined by internal structure rather than bulk material properties.

Researchers have investigated multiple parameters including print temperature, build plate temperature, layer thickness, print speed, orientation, raster angle, infill pattern/density, storage conditions, post-processing, and aging. However, material specifications (color, diameter, manufacturer) and equipment variables (open/closed build environment) often receive inadequate attention in studies.

Layer height—typically limited to half the nozzle diameter—represents one of the most studied FDM parameters. While increased layer height reduces print time, it compromises part resolution. This trade-off between production efficiency and detail reproduction requires careful consideration.

Academic consensus regarding layer height's influence on mechanical properties remains divided. Some studies report minimal effect on PLA part strength, while others identify layer height as the predominant factor affecting ultimate tensile strength (UTS). Contradictory findings exist regarding trends—most researchers observe increased UTS with reduced layer height, though some report inverse relationships or optimal intermediate ranges.

These discrepancies likely stem from variations in parameter combinations creating distinct thermal conditions, compounded by wide layer height ranges (0.06mm to 0.6mm) across studies.

Research examining color's influence on PLA mechanical properties across different layer heights remains scarce. Many studies omit specimen color entirely, reflecting conventional assumptions about its insignificance. Manufacturers typically provide identical material data for all PLA colors, yet pigment additives may alter thermal behavior—affecting interlayer adhesion and ultimately mechanical performance.

Emerging evidence suggests UTS variations up to 31% between identically printed colored PLA samples. However, no existing studies comprehensively analyze color and layer height interactions on UTS.

Extensive research confirms layer height's substantial impact on PLA part precision. Within the 0.05mm to 0.5mm range, most studies demonstrate superior dimensional accuracy with reduced layer heights, though deviations vary across X, Y, and Z axes depending on build orientation.

One notable investigation correlated print speed (50-70mm/s) and layer height (0.10-0.20mm) with dimensional accuracy for featured test pieces. Findings emphasized parameter-geometry interdependence, though the narrow layer height range (0.10-0.20mm) represents typical PLA precision benchmarks.

Only two studies explicitly identify PLA color as affecting dimensional accuracy, neither examining color-layer height interactions. One established optimal color-orientation combinations (white/gray/black) for precision, while another (using pink/gray/green/transparent samples at 0.5mm layers) studied pigment effects at varying temperatures. Most studies lack complete material specifications when color isn't a controlled variable.

This study evaluates how PLA color influences the relationship between layer height and both mechanical strength/dimensional accuracy in FDM printing. By isolating color (natural, black, red, gray) and layer height (0.05mm, 0.10mm, 0.15mm, 0.20mm) as sole variables while maintaining consistent printing parameters, the research aims to clarify these critical interactions.