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Material selection is one of the most important decisions when using an FDM 3D printing service. Each thermoplastic used in FDM printing offers distinct properties that directly affect part strength, appearance, durability, and functional performance.
In FDM (Fused Deposition Modelling), thermoplastic filament is fed into a heated nozzle where it is melted and extruded through a fine tip. The melted material is then deposited in precise layers, which solidify to form the final 3D geometry. This seemingly straightforward process conceals significant complexity, as each thermoplastic has unique properties that influence how it melts, flows, bonds between layers, and cools.
The success of a print depends not only on design accuracy or machine calibration, but significantly on how the selected material behaves both during printing and under actual service conditions. For example, a material prone to warping, such as ABS, can lead to print failures unless printed in a temperature-controlled environment. Others like PLA print cleanly but cannot tolerate elevated service temperatures, making them unsuitable for mechanical or outdoor use.
Field insight: Many part failures can be traced not to design errors, but to inappropriate material choice for the part’s intended application.
Material selection has far-reaching consequences. It affects not only how reliably the part prints, but also its mechanical properties, dimensional accuracy, and surface finish. Chemical resistance is essential for parts exposed to oils, solvents, or industrial cleaners. Environmental durability comes into play for components subjected to UV radiation, moisture, or thermal cycling. Additionally, the chosen material will impact how easily a part can be post-processed. Some thermoplastics are ideal for drilling and sanding, while others are prone to cracking or delamination under such conditions.
Understanding the full range of material properties, and how these properties align with the part’s functional requirements, is fundamental to achieving a successful outcome in FDM printing.
FDM printing involves the deposition of melted thermoplastic filament through a heated nozzle, layer by layer, onto a build platform. This additive process builds parts from the bottom up, with each new layer bonding to the one below it. While the principle is simple, the behaviour of different materials during extrusion, cooling, and bonding plays a critical role in determining the final part’s performance and dimensional accuracy.
Different polymers respond uniquely to temperature and stress. For instance, PLA has a low melting point and minimal shrinkage, which contributes to its high dimensional stability. ABS, on the other hand, has a higher glass transition temperature but tends to shrink significantly as it cools, which can cause warping if environmental conditions are not controlled. PETG offers a balance between ease of printing and functional strength, but it is sensitive to moisture absorption, which can affect surface quality and print consistency.
Other key variables include viscosity, flow rate, and thermal expansion, all of which affect how consistently material is laid down, how well layers fuse, and how fine the achievable detail is. The final quality of an FDM part is a combination of printer calibration, material choice, and environment control. Understanding these interactions is essential for engineers aiming to achieve reliable, high-quality prints in both prototyping and production contexts.
To understand how different materials perform in practical applications, see our detailed FDM 3D Printing Service page.
PLA is valued for its low print warping, precision, and biodegradability. It performs well in low-stress, indoor environments and is favoured for design validation and non-functional mock-ups. However, its brittleness and poor thermal resistance limit its use in demanding applications.
ABS provides better mechanical performance and higher heat tolerance compared to PLA. It is a common choice for end-use parts such as housings and mounts. Printability can be challenging without a heated enclosure, and warping may affect dimensional consistency if not properly managed.
PETG offers a balanced profile between toughness and ease of use. It delivers strong layer adhesion and chemical resistance, making it a reliable option for functional parts, fixtures, and assembly aids. Despite some sensitivity to moisture and UV, it remains a staple material for industrial applications.
| Material | Tensile Strength | Heat Deflection Temp | Print Difficulty | Applications |
|---|---|---|---|---|
| PLA | ~60 MPa | 55°C | Very Easy | Visual prototypes, models |
| ABS | ~40 MPa | 95°C | Moderate | Enclosures, automotive, functional parts |
| PETG | ~50 MPa | 70°C | Easy | Gears, hinges, wear parts |
| Nylon | ~70 MPa | 120°C | Difficult | Structural aerospace and industrial tooling |
| CF Nylon | ~85 MPa | 130°C | Advanced | Structural aerospace and industrial tooling |
Field insight: In many industrial scenarios, PETG serves as the optimal ‘default’ for balancing performance, ease of use, and repeatable print success.
Several specialist materials offer enhanced performance for demanding applications. Nylon delivers exceptional fatigue and wear resistance, making it ideal for moving parts like gears and bushings. Carbon fibre-filled filaments add stiffness and improve structural integrity for load-bearing parts. Polycarbonate is chosen for high-impact environments due to its toughness and heat resistance.
Materials like ULTEM and ASA are frequently specified in regulated industries. ULTEM is selected for applications requiring flame resistance and chemical stability, especially in aerospace and medical sectors. ASA, a UV-stable alternative to ABS, excels in outdoor environments.
Formlabs, a leading materials provider, offers insights into ASA’s durability for outdoor use here.
Case study: A Nottingham-based drone manufacturer switched from ABS to ASA for outdoor enclosures, significantly reducing UV degradation and improving reliability.
Applications with specialised environmental demands require materials tailored for performance. For parts exposed to heat or chemicals, selecting filaments with high heat deflection temperatures or solvent resistance is essential. PETG and PC are commonly chosen in chemically exposed environments, while ASA is selected when long-term outdoor durability is required.
Industries such as aerospace and medical manufacturing often require flame-retardant or biocompatible materials. ULTEM and select PC grades are engineered to meet flame-retardancy standards such as UL94. Meanwhile, biocompatible materials, such as those outlined by Formlabs in their biocompatible materials documentation, are suitable for skin or mucosal contact.
The range of materials available for FDM printing continues to grow, offering engineers greater flexibility in addressing complex design and performance needs. Conductive filaments, for example, enable the production of components for low-voltage circuitry or electrostatic discharge applications. These materials incorporate carbon or metal additives to allow electrical flow across printed surfaces, which is useful for printed sensors, embedded traces, or anti-static parts.
Flexible filaments such as TPU and TPE behave differently under stress. These elastomers can stretch and compress without breaking, making them ideal for vibration-damping mounts, gaskets, protective coverings, or wearable items. Unlike rigid polymers, flexible materials require careful control of print speed and retraction settings to avoid issues such as stringing or under-extrusion.
Metal-filled filaments contain a blend of thermoplastic and fine metallic powders to give the printed part a metallic appearance and added weight. While they do not provide the strength of true metal, they are popular for decorative, prototype, or tactile applications where the look and feel of metal is desirable without the need for CNC machining or metal sintering.
Environmental concerns are also shaping the FDM material landscape. Many manufacturers in the UK are actively adopting bio-based filaments and recycled blends. Recycled PETG and biodegradable PLA formulations reduce reliance on virgin plastics while maintaining usability. These alternatives are being evaluated not only for environmental credentials but also for stability and consistency in print performance.
Sustainability is no longer a secondary consideration. Businesses aiming to meet environmental compliance and corporate responsibility goals are beginning to specify low-impact materials as part of their procurement standards. Selecting a filament that supports long-term sustainability can also strengthen a company’s brand position in regulated or eco-sensitive markets.
Selecting the correct filament requires balancing performance with cost and printability. Key factors include:
Mechanical demands such as load-bearing, flexibility, or impact resistance
Environmental exposures including UV, moisture, or chemical contact
Desired surface finish and tolerance levels
Budget, lead time, and post-processing considerations
Consulting a provider early ensures the chosen material aligns with your part’s functional and commercial requirements. For further guidance, refer to our FDM 3D Printing Service page.
Mistakes in material selection often stem from underestimating environmental demands or overestimating material capabilities. A common error is using PLA for parts exposed to heat or sunlight, which leads to softening or warping. ABS may fail if printed in uncontrolled environments due to curling or cracking.
Moisture-sensitive materials like PETG and Nylon must be stored and printed in dry conditions. Engineers should also assess the entire lifecycle of the part—from production to end-use—to prevent performance issues.
Field insight: Poor material choices have led several UK SMEs to face functional failures or field recalls due to degradation, cracking, or environmental incompatibility.
Once material is selected, it’s essential to follow proven FDM design techniques for strength and accuracy.
A mechanical engineering firm in Nottingham initially used ABS for production fixtures but experienced significant warping, affecting alignment and function. Transitioning to PETG eliminated the need for heated enclosures, improved print consistency, and reduced scrap rates by 40%, leading to lower operational costs and improved reliability.
To understand how these materials perform across real-world applications, see how firms use FDM in UK manufacturing.
For structural strength, carbon fibre-filled Nylon and polycarbonate provide the highest tensile performance. These are suitable for aerospace tooling and industrial jigs. PETG is a good general-purpose material offering reliable strength for most functional parts.
ABS is better suited for functional components due to its impact resistance and thermal stability. PLA is appropriate for non-functional models or indoor visual prototypes.
PETG performs well in humid and chemically exposed environments but lacks UV stability. For long-term outdoor use, ASA is the preferred material.
Consider mechanical stress, exposure conditions, and required precision. Involving your 3D printing partner early ensures that the selected material aligns with both performance and budget goals.
Yes, when used strategically. While high-performance materials have higher costs, they reduce rework, improve part longevity, and deliver better lifecycle value. PETG remains a popular choice for balancing cost and performance.
Selecting the right FDM material ensures that your parts meet both performance and commercial goals. Our engineers support UK clients with expert advice, helping you reduce costs and improve reliability.
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