Difference Between DLP 3D Printer, SLA 3D Printer, FDM 3D Printer And Resin 3D Printer
Feb 07, 2025
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- DLP 3D printer application
- DLP 3D printer working principle
- DLP 3D printer vs. other 3D printing technologies
- SLA 3D printer application
- Difference between SLA 3D printer and FDM 3D printer
- What is SLA 3D printer
- FDM 3D printer working principle
- What is FDM 3D printer
- FDM 3D printer brand comparison
- Common brands of Resin 3D printer
- What is Resin 3D printer
- Resin 3D printer application
5. Difference between DLP 3D printer, SLA 3D printer, FDM 3D printer and Resin 3D printer
- Difference between DLP 3D printer and SLA 3D printer
- Difference between DLP 3D printer and FDM 3D printer
- Difference between SLA 3D printer and Resin 3D printer
DLP 3D Printers
DLP 3D printing technology is based on digital light processing and uses projection and photosensitive resin for printing. It has several key components inside, including a removable resin tray, a build platform, a projector, and a Z-shaped gantry. During operation, light passes through the transparent screen built into the resin tray, allowing the light to contact the resin, thereby curing a specific-shaped printing layer. This layer cures on the build platform, and the build platform is inverted along the Z-axis. The platform is semi-submerged in the resin, and the distance between it and the resin tray is one printing layer (usually 10 to 25 microns, depending on the machine). When one printing layer material is cured, the machine moves the Z-axis upward to peel the printed layer from the transparent film covering the tray, and then repeats this step until the part is completed.
DLP technology has many advantages. For example, it has very high precision, reaching around two microns, and can manufacture tiny structures. Using a fine layer thickness can achieve high precision in the z-direction, thus enabling the manufacture of detailed structures. Additionally, in terms of surface quality, it can compare with injection molding. It is difficult to see the printing layer lines on the printed parts (except when observed under a magnifying glass), and basically no strict post-processing operations are required after printing (except for cases where stricter tolerances are needed). At the same time, DLP has developed rapidly in material development and innovation. In recent years, stronger and more robust photosensitive polymers have continuously entered the market, covering various materials such as transparent, biological, rubber, high-temperature, and rigid materials.
SLA 3D Printers
SLA 3D printing, namely Stereolithography Apparatus (SLA), also known as stereolithography, is one of the earliest developed 3D printing technologies. It was first proposed by Charles W. Hull in 1984 and obtained a US national patent.
The SLA process uses photosensitive resin as the material. Under computer control, ultraviolet lasers scan the liquid photosensitive resin to solidify it layer by layer. Specifically, the liquid tank is first filled with liquid photosensitive resin. The ultraviolet laser beam emitted by a helium-cadmium laser or an argon-ion laser scans row by row and point by point on the surface of the liquid photosensitive resin according to the layered cross-sectional data of the workpiece under the manipulation of the computer, causing the resin thin layer in the scanned area to undergo a polymerization reaction and solidify, thus forming a thin layer of the workpiece. When one layer is solidified, the workbench moves down a layer thickness distance. New liquid resin covers the previously solidified resin surface. After a doctor blade levels the liquid surface, the next layer of laser scanning and solidification is carried out. The newly solidified layer firmly adheres to the previous layer. This process is repeated until the entire workpiece is completed.
SLA technology has relatively high precision and surface quality and can print objects with highly complex shapes. The consumables it uses are currently mainly photosensitive resin, which can be used to manufacture various molds and models. It can also be used to replace the wax pattern in investment casting by adding other components to the raw material with an SLA prototype. This technology is widely used in many fields such as healthcare (customized medical devices and prosthesis manufacturing), automotive manufacturing (prototype making and rapid mold manufacturing), and art design (transforming creative ideas into physical objects).
FDM 3D Printers
FDM (Fused Deposition Modeling) refers to fused deposition modeling, which is a widely known additive manufacturing technology. The principle of this technology is relatively simple. Various filaments (such as engineering plastic ABS, polylactic acid PLA, etc.) are heated to a molten state, and then the 3D printer stacks and forms the 3D model layer by layer according to the digital blueprint. The printing process consists of several key steps: First, before FDM printing, its built-in software automatically reads the 3D model data and slices it; after slicing, the liquid material melted at high temperature is extruded through the print head. After extrusion, it quickly solidifies when it meets the cold; then, a three-dimensional object is formed through the swinging of the print head on the plane and the downward displacement of the print bed. In the process of continuous repetition, the construction of the 3D entity is achieved.
FDM technology has certain advantages: Based on a simple and understandable principle, it is easy to operate, making it an excellent choice for beginners in 3D printing. Moreover, the operation and maintenance of FDM 3D printers are relatively simple. In terms of price, the price range of its printers is wide, from low-cost home or hobbyist models to expensive high-end industrial-grade equipment, which can meet the needs of different user groups. In terms of materials, the types of materials available for FDM technology are constantly increasing. The materials have different performance characteristics and are available in a variety of colors. The finished products printed with the thermoplastic materials used have good durability and strength. At the same time, its printing materials are provided in the form of spools, which are convenient for handling and quick replacement. However, FDM also has disadvantages. First, the print head has a mechanical structure, and the printing speed is relatively slow (especially when printing large-size or batch models); second, the dimensional accuracy is poor, the surface is relatively rough, and there is a staircase effect, so it is not very suitable for printing high-precision assembled parts; third, support structures need to be designed and fabricated, resulting in material waste, and for models with complex structures, the support structures are not easy to remove.
Resin 3D Printers
Resin 3D printers use resin materials for printing. It may be a relatively broad concept that can include printers that use different printing technologies but are based on resin materials. For example, both SLA and DLP 3D printing technologies use resin as the printing material. SLA uses an ultraviolet laser focused on the surface of the photocurable material and scans according to a preset path to solidify the photocurable material into a shape. DLP cures layer by layer by projecting an image onto the liquid photosensitive resin layer through a projector. Both rely on the photocuring properties of the resin material during the forming process. Therefore, in a sense, they can be regarded as specific types of Resin 3D printers.
The Relationships among DLP, SLA, FDM, and Resin 3D Printers
Differences
Forming Principle:
DLP: DLP is digital light processing. It uses a projector to project an image onto a suspended photosensitive resin layer for curing and is a surface forming technology. Layers of resin are quickly cured by the projection light irradiation, thus forming a 3D model.
SLA: SLA is based on an ultraviolet laser. It uses a laser beam to scan the liquid photosensitive resin row by row and point by point, forming a line from points and a surface from lines, gradually forming a layer of the component. Compared with DLP, the laser scanning speed is relatively slow, but the accuracy is also very high.
FDM: The principle of FDM is completely different from the previous two. It melts the filamentous material (such as ABS, PLA, etc.) by heating and extrudes it from the nozzle. The 3D model is stacked through the movement of the print head on the plane and the up and down movement of the print platform. It belongs to the filament extrusion forming technology and has differences in accuracy compared with the light curing-based technologies.
Resin 3D Printers (specifically referring to SLA and DLP types here): As mentioned before, it relies on resin materials. SLA scans the resin with a laser, and DLP irradiates the resin with projection. However, in either case, it utilizes the property of resin to solidify under light, which is different from the principle of heating and extruding filamentous materials in FDM.
Accuracy Performance:
DLP and SLA: These two technologies show relatively high accuracy. Due to the precise control of the resin by light, the printing layer thickness can be very small. Generally, the surface smoothness is good, and obvious layer lines are hardly visible. They are very suitable for printing fine structures and models that require high precision. They are widely used in fields such as jewelry and dental medical models, and perform well in scenarios with extremely high requirements for dimensional and shape accuracy.
FDM: The surface of FDM printed products will have a relatively obvious layer-by-layer effect because it is formed by extruding filaments and stacking them layer by layer. Its accuracy is relatively lower than that of DLP and SLA, and it is not very suitable for small-size complex components with high-precision requirements.
Printing Materials:
DLP and SLA: Both use photosensitive resin as the printing material. However, since RESIN is a printer under a relatively broad concept, when it is limited to DLP and SLA types, the resin has specific properties. For example, it will have different properties in terms of transparency, hardness, elasticity, etc. And for specific other physical and chemical properties such as biocompatibility, it will be formulated according to different applications to suit special industries such as healthcare and handicrafts. Some resins may only be suitable for specific printer models or need to be adjusted according to printer parameters.
FDM: It mainly uses filamentous thermoplastic materials, such as the common PLA and ABS. These materials are fundamentally different from photosensitive resin and have unique features in terms of mechanical properties, melting point, adhesiveness, etc. For example, PLA is a biodegradable thermoplastic material, suitable for scenarios with high environmental requirements; ABS has better toughness and strength, suitable for product function testing.
Printing Speed:
DLP: Due to the use of projection imaging, one layer of resin is cured at a time, so its printing speed is relatively fast, and it can complete the printing of a model in a relatively short time.
SLA: SLA uses a laser beam to scan single points or rows, and the printing speed is slow, especially when printing large-size or complex-structured models.
FDM: The printing speed of FDM is limited by factors such as the nozzle structure and the material extrusion speed. The printing speed is usually slower than that of DLP, but the speed can be appropriately increased if the layer thickness is set larger and the printing detail requirements are not high.
Equipment Price and Material Cost:
DLP and SLA: These two types of printers and the photosensitive resin materials they use are relatively expensive. DLP and SLA printers have high technical and equipment costs, and the price of photosensitive resin may be over a thousand yuan per liter. Because the realization of their high precision depends on special optical and mechanical components, as well as high-precision resin formulation and usage environment requirements, all of these will increase the equipment and material costs.
FDM: The price range of FDM printers is relatively wide and relatively low. The price spans from low-cost home models to high-end industrial models, which can meet the needs of different users. Moreover, the printing materials are relatively cheap. High-quality PLA printing materials can be purchased for around two to three hundred Hong Kong dollars per kilogram.
Connections
Connection in Material Principle: Although the forming principles of SLA, DLP, and FDM are different, from the material perspective, SLA and DLP both use resin as the printing material and can provide printed results with high precision and smooth surfaces. In this sense, they belong to the same category in resin material processing and are different from FDM.
Complementation and Intersection in Application Scenarios: Although their respective characteristics make them suitable for different application scenarios. For example, FDM is suitable for some home scenarios, initial product testing, and printing of relatively macroscopic models due to its low cost and other factors; SLA and DLP are used in healthcare (such as dentistry and orthopedics where high precision and biocompatibility are required), handicraft manufacturing, and the precise manufacturing of complex structures due to their high precision. However, in some product development processes, these several technologies may be used simultaneously. For example, in the early stage of product development, FDM can be used to quickly verify the design. If it is found that the dimensions and functions can meet the requirements but the appearance and surface effects need to be improved, SLA or DLP printers may be used for refined printing later.
Synergy in the Technological Development Trend: They all develop in the directions of increasing printing speed, improving printing accuracy, and reducing costs. For example, FDM is striving to improve accuracy by optimizing the nozzle structure and adopting new control algorithms to try to reduce the surface roughness; SLA and DLP are also exploring new resin materials or improving the optical path to reduce costs and increase speed.