In the realm of modern manufacturing, additive manufacturing (AM) emerges as an innovative solution to optimize processes, offering unparalleled design flexibility, shortened lead times, and heightened production adaptability. From filament extrusion to powder fusion and resin-based processes, AM technologies have proven beneficial for reducing lead times in critical replacement parts, reshaping prototyping, and streamlining the supply chain.
However, the widespread adoption of 3D printing at factory levels faces several significant challenges. Foremost among these is the substantial initial investment required for machinery, alongside the ongoing costs associated with raw materials and the scarcity of a skilled workforce proficient in additive manufacturing technology. Industries seek a manufacturing process capable of delivering superior quality and productivity at a competitive cost per part.
Beyond these financial and personnel obstacles, the final printed part encounters numerous technical issues such as poor mechanical properties and limited surface finish, compromising their suitability for industrial-scale deployment.
From filament to powder and resin technologies, in this blog post, we delve into the complexities that confront each technology in achieving widespread adoption of AM in production environments. Addressing these multifaceted challenges is essential to unlocking the full potential of 3D printing in meeting the demands of modern manufacturing across various vertical markets.
Mechanical Properties
In 3D printing, parts are fabricated layer by layer employing different methods. These techniques have a notable impact on the molecular composition of parts produced by each technology, consequently impacting their mechanical properties.
Filament-based additive manufacturing (AM) technologies, such as Fused Deposition Modeling (FDM), offer a significant advantage in processing thermoplastics, a material highly valued for its mechanical properties in factory-level applications. Because thermoplastics maintain their physical and chemical properties at higher temperatures, they can provide enhanced mechanical properties crucial for operational efficiency and product quality.
However, despite being the most widely used method among 3D printing techniques, pure thermoplastic parts built by filament-based technologies often lack strength as fully functional and structural components. This is due to an incomplete adhesion between layer surfaces in filament-based AM processes. Even with partial melting of the preceding layer, adjacent layers only achieve partial adhesion, resulting in weak connections and reduced overall strength. This poor layer adhesion leads to anisotropic behavior in printed parts, where mechanical properties vary depending on layer orientation, with properties differing between the XY plane and the Z direction.
Unlike filament-based methods, powder technologies ensure uniform material distribution and fusion throughout the printed part, resulting in consistent mechanical properties in all directions. This isotropic behavior enhances the reliability and predictability of printed end-use parts, meeting the stringent requirements of industrial applications.
In Resin-based technologies, parts can be produced with tailored mechanical properties. This capability stems from the careful formulation of resins, which impacts every aspect of the production process, including printing parameters and the properties of the printed object. However, variations in the curing and polymerization processes inherent to these technologies may sometimes result in an uneven distribution of material properties within the printed part, potentially leading to unbalanced mechanical characteristics.
Surface Finishes
The surface finish of 3D printed parts encompasses aspects such as smoothness, texture, and overall appearance. It reflects how well-defined and uniform the surface features are, including layer lines, surface irregularities, and any post-processing treatments applied. This quality varies widely based on the printing technology, printer quality, and chosen raw materials. Additionally, the design of the part and its orientation during printing significantly influence the final surface quality.
In filament-based technologies, the surface finish of printed parts often exhibits visible layer lines due to the layer-by-layer deposition of filament material. These layers can result in an irregular texture, especially on sloping or curved surfaces, detracting from the overall smoothness of the part.
Powder-based technologies, such as Selective Laser Sintering (SLS) or Selective Laser Melting (SLM), produce parts by fusing layers of powdered material using a laser. While these methods offer high accuracy and resolution, the surface finish tends to be rougher compared to other 3D printing methods. This roughness is a result of the powder particles remaining on the surface of the printed part after the sintering or melting process.
Productivity
The layer-by-layer rastering process in Filament technologies is relatively slow, making it inefficient for producing parts in large batches. The time required to build each part can be substantial, limiting the overall throughput and scalability for mass production.
Resin-based technologies vary in productivity depending on the specific method used. Stereolithography (SLA) uses a point-by-point laser to cure the resin layer by layer, which can be slow because the laser must trace the entire cross-section of each layer individually. This makes SLA less productive for large-scale production.
Digital Light Processing (DLP) and Liquid Crystal Display (LCD) Printing technologies cure entire layers of resin simultaneously using a projected light source or LCD screen, respectively. This significantly increases productivity compared to SLA, as it allows for faster layer curing and shorter build times. DLP and LCD printing are more suitable for medium to large-scale production runs where both speed and detail are important.
Powder-based technologies, such as Selective Laser Sintering (SLS) and Selective Laser Melting (SLM), are methods that can produce multiple parts simultaneously within a single build volume, allowing for efficient and rapid manufacturing. Parts can be printed quickly on demand, facilitating quick iteration and reducing lead times. However, post-processing in powder technologies, such as removing excess powder, cleaning, and finishing the parts, can be time-consuming.
Cost per part
In 3D printing, the cost per part for manufacturers is improving, but it remains a barrier to widespread adoption in production applications. Many factors influence the price of a printed part across different technologies, including material costs, production time, printer type, energy consumption, and post-processing requirements. Understanding these factors is crucial for making 3D printing a viable option for large-scale manufacturing.
In Filament Technologies, the cost per part can be relatively low due to the affordability of 3D printing machines and materials. Thermoplastic filaments such as ABS and PLA, as well as other widely used 3D printing materials, are generally inexpensive and ideal for producing multiple parts cost-effectively. However, the layer-by-layer rastering process is inherently slow, which negatively impacts productivity and efficiency when producing parts in large quantities. This extended build time increases labor and operational costs, making it challenging to achieve cost efficiency in high-volume production scenarios.
The cost per part in resin-based technologies is notably significant. Firstly, resin materials are generally more expensive compared to other additive manufacturing materials. Secondly, the post-processing requirements for resin printing, including cleaning, curing, and support removal, often demand specialized equipment and labor, leading to additional costs.
In Powder-based technologies, like Selective Laser Sintering (SLS) benefit from economies of scale, allowing multiple parts to be produced simultaneously within a single build cycle. This efficiency reduces the cost per part significantly, although post-processing steps, such as powder removal and surface finishing, can add to the overall cost.
CAPEX
As mentioned earlier, 3D printing machines and materials for Filament technologies have relatively low costs, resulting in lower CAPEX. This is why Filament technologies, like FDM, are widely adopted, particularly by companies of any size seeking to implement AM applications in production environments due to their affordability.
Adopting resin-based technologies for production applications entails a high CAPEX, largely due to the complexity of the workflow involved. Unlike simpler additive manufacturing methods like FDM, resin-based technologies require meticulous handling and specialized equipment to ensure both quality and safety. A dedicated workspace is necessary to handle toxic resins and maintain a controlled environment. This setup includes proper ventilation systems, safety gear, and contamination control measures, all of which contribute to the initial investment. Additionally, the workflow itself is intricate, requiring post-processing steps like depowdering, cooling, and re-mixing resin, all of which demand specialized equipment and skilled operators. These factors contribute to the significant initial investment required for resin-based technologies, making them a substantial but potentially rewarding investment for companies seeking high-quality, specialized production capabilities.
Powder-based additive manufacturing technologies offer numerous advantages, but their high CAPEX poses a significant barrier for many businesses. For instance, in SLS methods, one of the primary cost considerations is the machine itself. The initial purchase price of an SLS machine can reach hundreds of thousands of dollars or more, depending on the size and capabilities of the system, making it a substantial investment for companies looking to start production.