FDM 3D Printing
Fused Deposition Modelling
Fused Deposition Modeling (FDM), also known as Fused Filament Fabrication (FFF), is a popular 3D printing technique where filament made of thermoplastic material is fed through a heated extruder onto a plate in successive layers. FDM is like a computer-controlled hot glue gun where the material is melted and precisely placed to build up the desired object layer by layer, enabling users to create three-dimensional shapes and structures. This versatile and cost-effective method enables producing anything from small-scale prototypes and intricate architectural models to large-scale functional parts, fixtures, and jigs. Providing the ability to rapidly prototype and produce custom parts, FDM has become a go-to solution for innovators across various industries.
Materials
In FDM printing, a wide range of thermoplastic materials can be utilized, offering versatility for different applications. Common thermoplastics suitable for hobbyist use and ease of printing include Acrylonitrile Butadiene Styrene (ABS), known for its durability and impact resistance, making it suitable for functional prototypes and end-use parts. Polylactic Acid (PLA), a biodegradable material derived from renewable resources, offers an environmentally friendly option. PLA has a low melting temperature, making it easy to extrude and reducing energy requirements. It exhibits good dimensional stability, low warping tendencies, and offers good layer adhesion, contributing to the strength of printed objects. Polyethylene Terephthalate Glycol (PETG) provides improved strength and chemical resistance, making it suitable for engineering applications. Additionally, FDM printing incorporates the use of advanced materials such as Polyether Ether Ketone (PEEK), Polyetherketoneketone (PEKK), Polyetherimide (Ultem) and carbon fiber- or metal-reinforced materials. These high-performance materials offer exceptional thermal resistance, chemical inertness, and mechanical properties, making them ideal for demanding applications in industries like aerospace and medical fields. Nylon with Glass Fiber (PA-GF) combines the strength of nylon with added rigidity and toughness due to the glass fiber reinforcement, making it suitable for structural components. The material choice depends on the desired characteristics of the printed object, such as strength, flexibility, heat resistance, chemical resistance, and specialized applications, allowing FDM to address a wide range of manufacturing needs.
Machines
There is a wide variety of FDM 3D-printing machines available, categorized into three tiers based on their capabilities. The desktop/consumer class includes popular brands such as Prusa (which makes the MK3 and MK3S printers, among others), Creality (which makes the Ender 3 Pro, CR4, and CRS, among others), and Bambu Lab (which makes the P1P and X1 series printers), known for their reliability, user-friendliness, and extensive community support. In the prosumer/semi-industrial class, brands such as Raise3D, Modix, and Fusion3 offer advanced features and larger print volumes, making them suitable for professional and small-scale industrial use. Finally, the industrial class includes brands like Essentium, Stratasys, and 3DGence, known for their printers’ high-speed and large-scale production capabilities. Each machine and its applicable software offers many variables that can be adjusted to achieve desired print outcomes. Layer height determines the thickness of each printed layer and affects the level of detail and surface finish. A smaller layer height provides finer details but increases print time. Print speed determines how quickly the extruder moves, where higher speeds decrease print time but can compromise print quality, while slower speeds yield more precise results. Temperature settings control the extruder, build plate, and ambient temperatures, which are crucial for proper material flow and layer-to-layer adhesion. Certain materials require specific temperature and enclosure configurations for proper printing. Adjusting these variables allows users to optimize their prints for different applications, balancing print quality, time, and material usage.
Post-Processing
Printed objects often require post-processing steps to achieve a desired appearance or smoothness, varying based on machine, print parameters, and desired level of detail. The requirement of post-processing is one disadvantage associated with FDM, since there are visible layer lines on a printed object’s surfaces. During the printing process, supports are often generated to provide stability for overhanging or intricate features. While supports are crucial for maintaining the structural integrity of the object, their removal can be time-consuming and may leave behind minor marks or blemishes. These supports are typically made of the same material as the object but designed to be easily removable by hand or with simple tools. Some printers are capable of printing soluble supports from a dual print head, enabling support removal via immersion in a water or chemical bath. After printing, supports need to be carefully detached to reveal the intended geometry and minimize visible marks or blemishes. Post-processing for FDM begins with support removal, followed by surface treatments and aesthetic modifications. Common surface treatments after support removal include sanding, priming, and painting. Sanding can remove layer lines and imperfections, while priming provides a smooth base for painting. Additionally, post-processing can involve applying coatings, such as clear varnish or UV-resistant finishes, to enhance durability and aesthetics. Post-processing techniques play a crucial role in achieving the desired final appearance and functionality of the printed objects.
Pros and Cons
One of the notable advantages of FDM 3D printing is its cost-effectiveness for low-quantity, high-complexity production relative to other manufacturing methods. Traditional techniques like injection molding or CNC machining can be expensive, particularly for small production runs or prototypes. FDM eliminates the need for costly molds or tooling, making it more affordable. Moreover, FDM offers quick turnaround times, enabling rapid prototyping and iterative design processes. Another advantage is the capability to produce complex geometries with internal structures (e.g., customizable infill patterns), permitting lightweight and optimized designs. Additionally, certain FDM applications utilize customizable, open-source software, which provides users with flexibility and control over the printing process. This enables easy modification of printing parameters, advanced slicing options, and compatibility with a wide range of design software. The open-source nature of FDM software encourages collaboration, innovation, and the sharing of knowledge within the 3D printing community, further expanding the possibilities and advancements in the field. Inter-layer adhesion can be problematic with FDM printing. Factors such as ambient temperature, print speed, and material properties can impact the bonding between layers, potentially resulting in weaker mechanical strength. Certain FDM printers offer enclosed build chambers or heated build plates to address these issues by maintaining a stable printing environment and enhancing layer adhesion.