How to Use This Calculator
- 1
Select Filament Material
Choose your desired 3D printing filament from the dropdown list (PLA, ABS, PETG, TPU, Nylon, or Polycarbonate).
- 2
Review Your Results
The calculator will display key mechanical properties like Izod impact strength, flexural modulus, print difficulty, and recommended use cases for the selected material.
Example Calculation
An engineer needs to select a 3D printing filament for a prototype and wants to understand the impact resistance and other properties of PLA.
Filament Material (select)
PLA
Results
3 kJ/m²
Tips
Consider Real-World Loading
While Izod impact strength is a useful comparative metric, consider the actual loading conditions your part will experience. A material with moderate Izod strength but high ductility (like PETG) might perform better under repeated, lower-energy impacts than a brittle, high-Izod material.
Account for Print Settings
Filament properties can vary significantly with print settings. Higher infill percentages, specific infill patterns (e.g., gyroid), and optimized layer adhesion can dramatically improve the impact resistance and overall strength of a printed part, regardless of the base material.
Evaluate Environmental Factors
Some materials, like ABS, are more susceptible to UV degradation and warping in outdoor environments, which can compromise their impact resistance over time. Always consider the intended operating environment when selecting a filament for critical applications.
Material Selection for Additive Manufacturing
The Impact Resistance by Material Calculator is an essential tool for engineers and hobbyists using 3D printing, enabling rapid comparison of key mechanical properties across common filaments like PLA, ABS, PETG, TPU, Nylon, and Polycarbonate.
Understanding metrics such as Izod impact strength and flexural modulus is critical for selecting the right material for functional prototypes or end-use parts.
For instance, PLA, a common starting material, typically offers an Izod impact strength of only 3 kJ/m², making it suitable for decorative items but generally too brittle for high-impact applications where Polycarbonate (around 100 kJ/m²) would excel.
The Engineering Behind Material Impact Resistance
This calculator draws upon empirical data from standardized material testing to provide comparative insights into filament performance.
Izod impact strength, measured in kJ/m², is a key indicator of a material's toughness—its ability to absorb energy before fracturing.
Flexural modulus, in MPa, describes its stiffness.
By presenting these alongside print difficulty and recommended use, the tool helps users quickly match material properties to application requirements, preventing costly failures in printed parts.
The core data points are derived from material specifications, often from reputable sources like ASTM standards (e.g., ASTM D256 for Izod impact).
The calculations for specific impact strength and relative strength are comparative:
specific impact strength = Izod impact strength / density
relative strength vs polycarbonate = (Izod of material / Izod of polycarbonate) × 100
These relative metrics provide a normalized comparison across diverse materials, aiding in informed decision-making.
Comparing PLA's Properties for a 3D Print
An engineer needs to 3D print a prototype for an enclosure that won't experience significant impacts.
They are considering using PLA filament.
They want to quickly assess its impact resistance, stiffness, and printability.
- Select Filament Material: Choose
PLAfrom the dropdown.
Based on typical PLA material data (as assumed by the calculator):
- Izod Impact Strength:
3 kJ/m² - Impact Rating:
Brittle(typically ranking lowest among common engineering filaments) - Strength vs Polycarbonate:
3%(Polycarbonate is the benchmark at 100%) - Specific Impact Strength:
2.4 kJ·m/kg(indicating a low strength-to-weight ratio) - Flexural Modulus:
3500 MPa(relatively stiff) - Print Difficulty:
Easy - Recommended Use:
Best for non-structural or decorative parts
The results confirm that PLA is stiff but brittle, making it easy to print but unsuitable for parts requiring high impact resistance.
Material Selection for Additive Manufacturing
In 2025, the landscape of 3D printing filaments offers a vast array of materials, each with distinct mechanical properties suited for specific applications.
For high-impact components, engineers often turn to Polycarbonate (PC) or Nylon, which boast Izod impact strengths of around 100 kJ/m² and 60 kJ/m² respectively, making them ideal for protective gear or durable tools.
In contrast, general-purpose filaments like PLA (3-5 kJ/m²) and PETG (5-8 kJ/m²) are cost-effective but less robust for demanding environments.
Material selection is also heavily influenced by regulatory standards for specific industries, such as medical (e.g., biocompatible materials) or automotive (e.g., flame-retardant composites), requiring precise property matching beyond basic impact resistance.
When Not to Use Izod Impact Strength as the Sole Metric
While Izod impact strength is a widely used and valuable metric, it should not be the sole determinant for material selection, especially in complex engineering applications.
The Izod test uses a notched specimen, which creates a stress concentration point, making it excellent for comparing notch sensitivity but potentially misleading for unnotched designs.
It also measures impact at a single, high strain rate.
For parts exposed to repeated impacts, varying temperatures, or different strain rates, other tests like Charpy impact, drop weight impact, or fatigue testing may be more relevant.
Furthermore, Izod doesn't account for environmental factors like UV exposure, chemical resistance, or long-term creep, which can significantly degrade a material's performance over time, even if its initial Izod strength is high.
Always consider the full spectrum of operational conditions and design requirements.
Frequently Asked Questions
What is Izod impact strength?
Izod impact strength is a standardized test that measures a material's resistance to impact from a swinging pendulum. It quantifies the energy absorbed by a notched specimen before fracturing, providing an indication of a material's toughness and ability to withstand sudden loads without breaking.
How does flexural modulus relate to material stiffness?
Flexural modulus measures a material's resistance to bending or deformation under load. A higher flexural modulus indicates a stiffer material that will resist bending more, while a lower modulus signifies a more flexible material. This property is crucial for parts requiring rigidity or specific elastic behavior.
What makes a 3D printing filament 'tough'?
A tough 3D printing filament resists fracturing under impact and can absorb significant energy before breaking. This often correlates with a high Izod impact strength and good ductility, meaning the material can deform without immediately failing. TPU and Nylon are examples of tough, flexible filaments, while Polycarbonate is tough and rigid.
Why is print difficulty a factor in material selection?
Print difficulty indicates the challenges associated with successfully printing a specific filament, affecting print success rates and required equipment. Factors like warping, bed adhesion, temperature requirements, and moisture sensitivity contribute to difficulty. Materials like PLA are easy, while Nylon and Polycarbonate require more advanced setups.