How Do Filament Color Influence 3D Print Strength?

I. Introduction

Filament color is more than just aesthetics - it can alter the mechanical properties, thermal characteristics, and printing behaviors compared to natural materials.

This guide covers the impacts of colorants on common 3D printing filaments like ABS, PLA, PETG, TPU and more. Read on to learn how to achieve the best quality colored 3D prints.

Rainbow Silk PLA Filament

II. Color Impact on Mechanical Properties

Adding pigments and dyes to alter filament color often reduces the ultimate tensile and flexural strength of printed parts.

Tensile strength, which resists pulling forces, may decrease 15-25% for dyed filaments. Pure natural and white materials tend to have higher rigidity.

Pigments can also diminish impact resistance, making dyed prints more brittle and prone to shattering from sudden forces. The particles act as defects reducing ductility.

Hardness and wear resistance can be lower as well for dark colored prints. Adhesion between layers also suffers slightly compared to natural hues. Fatigue strength and layer bonding decrease too - colored parts tend to delaminate easier over time from repeated stresses.

Color of PLA filament can influence 3D printed part strength (photo: CNC Kitchen)

III. Effect of Color on Thermal Properties

The glass transition temperature, which marks the point where polymers transition from a hard glassy state to a rubbery state, differs across colors.

Darker colors like black or red generally have a Tg 5-10°C lower than natural or white materials. This makes them less heat resistant.

Conversely, lighter and brighter colors often increase the filament’s melting temperature slightly compared to unpigmented materials.

Coefficient of thermal expansion, which indicates how much the material dimensions change with temperature fluctuations, also depends on color. This affects dimensional accuracy.

Prints made by different filament colors (photo: Hackaday)

IV. Influence on Printing Properties

Dyes and pigments change the optimal processing conditions needed for high quality prints:

• Dark colors may require 5-15°C higher nozzle temp to extrude smoothly.
• Stringing, oozing, and bleeding are more common with brightly colored filaments.
• Warping and poor first layer adhesion are also issues with some colors as additives reduce bed sticking.
• Translucent and transparent colored materials lose optical clarity compared to unpigmented plastics.

V. Best Practices for Colored 3D Prints

Follow these tips to compensate for color effects:

• Test multiple temperatures to find the ideal for each colored filament.
• Increase first layer bed temperature and use adhesives to improve adhesion.
• Reduce speed for dyed filaments to help reduce stringing and increase precision.
• Minimize overhangs and angular geometry to reduce drooping and sagging.
• Reinforce highly stressed regions with higher infill percentages or alternate materials.
• Lean on darker plastics for decorative objects and lighter ones where strength is vital.

For prototypes, art pieces, or client presentations where consistent color is crucial, use filament from the same brand and manufacturing batch.

Varying amounts of colorants between batches can create noticeably different hues. For repeatable results, buying multiple spools together is best.

eSUN 3D Printer Filament PLA+ 1.75mm 1KG

VI. Conclusion

With some simple tuning and awareness of the impacts, colored 3D printed parts can turn out beautifully - improving strength just takes a few tweaks. When designing prints, consider how color may enhance aesthetics as well as affect functionality.

FAQS

1. Does filament color actually affect 3D print properties?

Yes, the dyes and pigments used to color 3D printing filaments can alter the mechanical, thermal, and printing characteristics compared to uncolored materials. Colorants generally reduce strength, heat resistance, and bed adhesion.

2. How does color changing filament work?

Color changing filaments like rainbow PLA blend various colored pellets in changing ratios when producing the filament. This creates color transitions from yellow to red to blue and so on throughout a spool.

3. What is the typical tensile strength of colored PLA filament?

On average, dried uncolored PLA has a tensile strength around 60-65 MPa. Colored PLAs are usually in the range of 45-55 MPa depending on the pigment levels. So color reduces strength by 15-25% but still sufficient for most applications.

4. Do darker filament colors have better temperature resistance?

No, actually darker pigmented colors tend to have a lower glass transition temperature than lighter or natural filament by 5-10°C. So darker prints are generally more prone to deforming in heat.

See Also

All You Need To Know About Rainbow PLA Filament

All You Need To Know: Silk Filament for 3D Printer

Everything You Need to Know About Clear 3D Printer Filament