2.1 Fused deposition modeling (FDM)

Fused deposition modeling (FDM) is a cornerstone of desktop 3D printing, enabling rapid prototyping and production of functional parts. This layer-by-layer approach uses heated thermoplastic filament extruded through a nozzle to create objects based on 3D model data.

FDM printers consist of interconnected mechanical and electronic systems, including extruders, print beds, and filament feeders. A wide range of thermoplastic materials can be used, from common PLA and ABS to specialized composites, each impacting part functionality and appearance.

Principles of FDM

• Fused deposition modeling forms the foundation of many desktop 3D printing systems used in additive manufacturing
• FDM technology enables rapid prototyping and production of functional parts through a layer-by-layer approach
• Understanding FDM principles provides insight into design considerations for 3D printed components

Thermoplastic extrusion process

Top images from around the web for Thermoplastic extrusion process

• 

  Fused Deposition Modeling - 3dprinting View original

  Is this image relevant?

• 

  tecnologiaiesolajara - Thermoplastics View original

  Is this image relevant?

• 

  Frontiers | 3D Printing of Metal/Metal Oxide Incorporated Thermoplastic Nanocomposites With ... View original

  Is this image relevant?

• 

  Fused Deposition Modeling - 3dprinting View original

  Is this image relevant?

• 

  tecnologiaiesolajara - Thermoplastics View original

  Is this image relevant?

1 of 3

Top images from around the web for Thermoplastic extrusion process

• 

  Fused Deposition Modeling - 3dprinting View original

  Is this image relevant?

• 

  tecnologiaiesolajara - Thermoplastics View original

  Is this image relevant?

• 

  Frontiers | 3D Printing of Metal/Metal Oxide Incorporated Thermoplastic Nanocomposites With ... View original

  Is this image relevant?

• 

  Fused Deposition Modeling - 3dprinting View original

  Is this image relevant?

• 

  tecnologiaiesolajara - Thermoplastics View original

  Is this image relevant?

1 of 3

• Involves heating thermoplastic filament to its melting point
• Molten material extruded through a heated nozzle
• Deposition occurs in a precise pattern determined by 3D model data
• Extruded material rapidly cools and solidifies, bonding to previous layers

Layer-by-layer deposition

• Build platform lowers incrementally after each layer completion
• Subsequent layers deposited on top of previous ones
• Layer thickness typically ranges from 50 to 400 microns
• Finer layers increase resolution but extend print time

Material feedstock types

• Filament spools serve as the primary material form
• Diameter standards include 1.75mm and 2.85mm
• Pelletized materials used in some industrial FDM systems
• Material selection impacts mechanical properties and print quality

FDM hardware components

• FDM printers consist of several interconnected mechanical and electronic systems
• Understanding hardware components aids in troubleshooting and maintenance
• Advancements in FDM hardware continue to expand capabilities in additive manufacturing

Extruder mechanism

• Hot end contains heating element and temperature sensor
• Nozzle diameter affects extrusion width and print resolution
• Cold end manages filament feeding and heat dissipation
• Direct drive vs Bowden tube configurations impact print characteristics

Print bed characteristics

• Provides foundation for the first layer adhesion
• Heated beds improve adhesion and reduce warping
• Common materials include glass, aluminum, and flexible build surfaces
• Bed leveling systems ensure consistent first layer height

Filament feeding system

• Stepper motor drives gear mechanism to push filament
• Tension adjustment crucial for consistent extrusion
• Filament runout sensors prevent print failures
• Multi-material systems may incorporate multiple feeders

Materials for FDM

• FDM technology supports a wide range of thermoplastic materials
• Material selection impacts part functionality, appearance, and print settings
• Ongoing research expands the portfolio of FDM-compatible materials

Common thermoplastics

• PLA offers ease of printing and biodegradability
• ABS provides durability and post-processing capabilities
• PETG combines strength with chemical resistance
• Nylon exhibits high toughness and wear resistance
• TPU enables flexible and elastic prints

Composite filaments

• Carbon fiber reinforced filaments enhance strength and stiffness
• Wood-filled materials create parts with wood-like appearance and texture
• Metal-filled filaments produce metallic aesthetics and increased density
• Ceramic-filled materials offer unique properties for specialized applications

Material properties vs printability

• Glass transition temperature affects print bed adhesion
• Thermal expansion coefficient impacts warping tendency
• Melt flow index influences extrusion behavior
• Moisture sensitivity requires proper filament storage and handling
• Mechanical properties may vary between printed parts and bulk material

FDM process parameters

• Process parameters significantly influence print quality and part properties
• Optimizing parameters involves balancing print speed, quality, and material behavior
• Understanding parameter interactions enables fine-tuning for specific applications

Nozzle temperature

• Affects material flow characteristics and layer adhesion
• Typical range varies from 180°C to 300°C depending on material
• Insufficient temperature leads to poor layer bonding and clogging
• Excessive temperature can cause material degradation and stringing

Layer height vs resolution

• Determines vertical resolution and surface smoothness
• Smaller layer heights increase detail but extend print time
• Typical range spans from 0.05mm to 0.4mm
• Adaptive layer height adjusts thickness based on geometry

Print speed considerations

• Faster speeds increase productivity but may reduce print quality
• Slower speeds improve detail and strength at the cost of longer print times
• Acceleration and jerk settings affect print accuracy and vibration
• Different speeds often used for perimeters, infill, and support structures

Support structures in FDM

• Enable printing of complex geometries with overhangs and internal cavities
• Proper support design balances part quality with ease of removal
• Advancements in support generation algorithms improve print efficiency

Overhangs and bridges

• Overhangs exceeding 45 degrees typically require support
• Bridging spans unsupported areas between two points
• Cooling fans and print settings can improve bridging performance
• Design modifications can reduce or eliminate support requirements

Support material types

• Same material supports offer simplicity but may be challenging to remove
• Dissolvable supports (PVA, HIPS) enable complex internal geometries
• Breakaway supports balance ease of removal with surface finish
• Tree supports minimize contact points and material usage

Post-processing removal techniques

• Mechanical removal using pliers or cutting tools
• Chemical dissolution for soluble support materials
• Sanding and finishing to improve surface quality after support removal
• Heat treatment to separate support interfaces in some materials

FDM print quality factors

• Multiple factors contribute to the overall quality of FDM-printed parts
• Understanding quality factors aids in troubleshooting and optimizing prints
• Balancing various quality aspects often involves trade-offs in print settings

Layer adhesion

• Interlayer bonding strength affects overall part durability
• Proper temperature and cooling settings crucial for good adhesion
• Z-axis alignment impacts consistency of layer bonding
• Post-processing techniques can improve interlayer strength

Warping and shrinkage

• Caused by thermal contraction during cooling
• More pronounced in large, flat parts and high-temperature materials
• Mitigation strategies include heated build chambers and rafts
• Material selection can significantly impact warping tendency

Surface finish characteristics

• Layer lines inherent to FDM process affect aesthetics
• Stair-stepping effect visible on curved or angled surfaces
• Outer wall settings influence surface smoothness
• Post-processing techniques (sanding, vapor smoothing) can improve finish

Applications of FDM

• FDM technology finds use across various industries and applications
• Versatility of FDM enables both prototyping and production of end-use parts
• Continuous advancements expand the range of FDM applications

Rapid prototyping

• Enables quick iteration of design concepts
• Functional prototypes for testing and validation
• Cost-effective for low-volume production runs
• Supports customization and personalization of products

End-use parts

• Aerospace industry uses FDM for lightweight components
• Automotive sector produces custom interior parts and tooling
• Medical field creates patient-specific prosthetics and anatomical models
• Consumer goods benefit from complex geometries and customization

Industry-specific use cases

• Architecture firms create detailed scale models
• Education sector utilizes FDM for hands-on learning
• Fashion industry explores 3D printed textiles and accessories
• Food industry experiments with customized molds and tooling

Advantages of FDM

• FDM technology offers several benefits that contribute to its widespread adoption
• Understanding advantages helps in selecting appropriate manufacturing methods
• Continuous improvements in FDM systems enhance these inherent benefits

Cost-effectiveness

• Lower initial investment compared to other AM technologies
• Affordable materials reduce ongoing production costs
• Minimal waste generation through additive process
• Reduced tooling costs for low to medium volume production

Material versatility

• Wide range of thermoplastics available for various applications
• Ability to print with engineering-grade materials
• Composite filaments expand material property options
• Multi-material printing enables functional gradients

Ease of use

• User-friendly interfaces on many desktop FDM printers
• Minimal post-processing required for many applications
• Relatively safe operation without hazardous materials or lasers
• Extensive online communities provide support and resources

Limitations of FDM

• Understanding limitations informs design decisions and technology selection
• Ongoing research and development aim to address these challenges
• Some limitations can be mitigated through careful process optimization

Mechanical strength issues

• Anisotropic properties due to layer-by-layer construction
• Potential weak points at layer interfaces
• Limited strength compared to injection molded parts
• Porosity can affect water-tightness and strength

Surface finish constraints

• Visible layer lines affect aesthetics and smoothness
• Stair-stepping effect on curved surfaces
• Limited resolution compared to some other AM technologies
• Post-processing often required for high-quality finishes

Size limitations

• Build volume constraints on most desktop FDM printers
• Larger parts may require segmentation and assembly
• Increased print times and failure risks for very large prints
• Warping and thermal management challenges in large prints

Recent advancements in FDM

• Continuous innovation drives improvements in FDM technology
• Advancements expand capabilities and applications of FDM systems
• Research focuses on addressing limitations and enhancing performance

Multi-material printing

• Dual extruder systems enable two-color or two-material prints
• Soluble support materials improve complex geometry printing
• Gradient material properties achievable through mixing extruders
• Enables functional integration of different materials within a single part

High-temperature materials

• Development of printers capable of processing PEEK, ULTEM, and other high-performance polymers
• Enhanced mechanical and thermal properties for demanding applications
• Requires specialized hardware (all-metal hot ends, heated chambers)
• Expands use of FDM in aerospace and medical industries

Large-scale FDM systems

• Increased build volumes enable production of larger parts
• Pellet-fed extruders improve material cost-effectiveness at scale
• Robotic arm systems offer virtually unlimited build volumes
• Applications in construction and large-scale manufacturing

FDM vs other AM technologies

• Comparing FDM to other additive manufacturing methods aids in technology selection
• Each technology offers unique advantages and limitations
• Hybrid approaches sometimes combine multiple AM technologies

FDM vs SLA

• FDM offers wider material selection and lower operating costs
• SLA provides higher resolution and smoother surface finish
• FDM parts generally stronger but more anisotropic than SLA
• SLA requires post-curing and has more limited build volumes

FDM vs SLS

• FDM enables easier multi-material printing and color options
• SLS produces stronger parts with more isotropic properties
• FDM typically has lower initial investment and operating costs
• SLS offers support-free printing of complex geometries

Comparative strengths and weaknesses

• FDM excels in affordability, ease of use, and material versatility
• SLA and SLS often preferred for high-detail or strong functional parts
• FDM more suitable for larger parts and faster prototyping
• Material properties and post-processing requirements vary significantly between technologies