3D printing, or additive manufacturing, has revolutionized the way we produce objects, from intricate jewelry to large-scale architectural models. The technology encompasses various methods, each with its own strengths and applications. This blog explores the different 3D printing techniques and evaluates which ones offer the highest accuracy.
Fused Deposition Modeling (FDM)
Fused Deposition Modeling (FDM) is one of the most common and accessible 3D printing methods. It works by extruding thermoplastic filaments through a heated nozzle, layer by layer, to build an object. FDM printers are widely used in both consumer and industrial applications due to their affordability and ease of use.
FDM’s resolution usually ranges from 400 microns (about the width of a pencil line) to 50 microns – the width of a fine human hair. Its dimensional accuracy usually falls in the 0.15% with an ultimate lower limit of 0.2mm. It’s great for prototyping, model-making and producing solid parts in short production runs. However, the types of plastic that can be used are limited, often having a rough surface texture compared to the finished parts, and the layer-by-layer method isn’t ideal for parts under load or strain.
Selective Laser Sintering (SLS)
Selective Laser Sintering (SLS) uses a laser to sinter powdered material, typically nylon, into solid objects (fusing without heating to the point of melting). The design is printed layer by layer from the bottom up. This method is popular in industrial applications due to its ability to produce strong, durable parts without requiring supporting structures.
SLS produces robust parts but with a relatively low resolution of 100-120 microns and a dimensional accuracy of 0.3%. It can be used with a range of common industrial materials such as glass, ceramic, metal, and plastic. These qualities do make it suitable for both prototyping and certain finished part production, including bespoke items such as jewelry.
MultiJet Printing (MJP)
MultiJet Printing (MJP) use inkjet technology to deposit tiny droplets of photopolymer resin, which are then cured with UV light. This method can produce high-resolution prints with multiple materials and colors.
Due to the lack of heat (and so elimination of any induced warping), the accuracy is good – typically 0.3% and a maximum of 0.2mm deviation. MJP can print with a resolution as high as 16 microns or about the size of a grain of pollen. The surface of the finished object is smooth, and MJP is suitable for use with sturdy plastics such as nylon. MJP can produce high-fidelity prototypes, low-volume production parts, and complex assemblies, which are good enough for producing parts for medical and scientific equipment and precision items for motorsport and aerospace applications.
Projection Micro-Stereolithography (PµSL)
PµSL is a high-tech refinement of traditional stereolithography using UV-LED light sources to cure photosensitive resins. The light is projected onto the resin via a micro-display, which selectively blocks the light, allowing an entire layer to be cured in a single cycle. This makes it up to five times faster than other printing methods capable of the same accuracy. This method can produce ultra-high-resolution prints with incredible detail – suitable for microchip electronic parts, tiny mechanical gears and valves and even microneedles and ‘organs on a chip’ in medical and scientific fields.
Currently, PµSL 3D printers are available with resolutions of 10 microns (the size of a dust particle) and in a 2-micron version – the size of a typical bread mould spore! This makes this the most accurate 3D printing method commercially available right now.
Conclusion
In the ever-evolving field of 3D printing, the choice of method depends on the specific requirements of the project, balancing factors like accuracy, material properties, cost, and production speed. As technology advances, we can expect even greater improvements in accuracy and efficiency, further expanding the potential of 3D printing in various industries.
