Comparison of 3D Printing Technologies: SLA and FDM
In our blog post, we will compare SLA and FDM technologies from additive manufacturing technologies in terms of usage areas, product features and material options.
Comparison of 3D Printing Technologies: SLA and FDM
Additive manufacturing is becoming a crucial part of modern manufacturing processes. So why? Undoubtedly, the effect of the variety of advantages it offers manufacturers and engineers is quite significant. Additive manufacturing technologies allow engineers to produce complex geometries and models in small quantities, affordably and quickly in prototype manufacturing. In addition, additive manufacturing has a variety of materials and technologies that can meet the different needs of many sectors. If we list some of these technologies:
MJF (Multi Jet Fusion)
SLS Technology (Selective Laser Sintering)
FDM Technology (Fused Deposition Modeling)
SLA Technology (Stereolithography)
DMLS Technology (Direct Metal Laser Sintering)
Binder Jet Technology
This article will compare SLA and FDM technologies, which are additive manufacturing technologies, in terms of usage areas, product features, and material options.
What is SLA, and How Does it Work?
SLA technology is a method that takes 3D prints as a principle by hardening the photopolymer resin of a light source of a specific wavelength. SLA uses “photopolymer resins” as a raw material that can change form with UV light. manufacturing beings inside a pool of resin. Laser beams are directed into the pool by precision mirrors, solidifying the resin for each layer. The first layer consists of “support structures” that allow the part to rest securely on the platform. The platform moves upward as the layers are processed, and the part is built.
What is FDM, and How Does it Work?
FDM is an additive manufacturing technique in which a product can be obtained by adding the thermoplastic material on top of each other in layers with the help of a hothead. The materials used are polymers, and the raw material form is in a wire-like form called a filament. The processing logic is similar to the glue gun we are familiar with; the thermoplastic filament is heated to its melting point. The plastic with increased viscosity is applied in layers from the nozzle to the platform while it is cooled simultaneously. FDM technology is the method that has the widest material range compared to other methods. In addition, the products produced with FM have the possibility of various post-manufacturing surface treatments. The usage areas, the materials, advantages and disadvantages of the two technologies, whose working logic is different, are just as diverse.
If details, high dimensional consistency and surface quality are essential in your parts to be produced, you can choose SLA without hesitation. In manufacturing with SLA technology, the layer thickness varies between 0.025 and 0.1mm. In FDM, this ratio is between 0.05 and 1mm. This makes the surface quality in manufacturings with SLA almost similar to the surface quality you can obtain with moulding methods. On the other hand, surface treatment can only achieve the same surface quality after manufacturing with FDM technology.
FDM technology has difficulty producing sharp corners in your design. In SLA technology, print sizes are not as generous as DFM. While the adequate build volume is 450 x 450 x 450 mm in SLA technology, it is 1295 x 902 x 1984 mm in FDM technology. This allows large parts to be produced quickly with FDM.
Differences in terms of Strength
The strength of the parts produced in both technologies varies according to the selected immaterial and the orientation determined before manufacturing. The tensile strength of the parts made in additive manufacturing on the Z-axis is lower than on the X and Y axes. For this reason, in both methods, manufacturing orientations are determined according to the area where the parts will be used. While receiving service from Tridi, our manufacturing engineers meet with customers before manufacturing and determine the print orientation.
Differences in Pricing
If we compare the costs of obtaining manufacturing service with FDM and SLA technologies, although the prices in both technologies vary according to the materials used, FDM technology is much more advantageous than SLA technology. manufacturing with frequently used materials such as PLA and ABS is much more economical than manufacturing with SLA technology.
Differences Concerning Materials
In SLA technology, some resins are used as materials to meet different needs. If we talk about these resins briefly:
Standard Resin: Contains white and grey colour options, with medium mechanical properties but excellent surface properties. It is the highest quality solution for visual prototypes.
Transparent Resin: It is the most used resin in SLA technology. It has a transparent image. It is possible to obtain a glassy appearance in the products. In addition, the surface can be made more transparent by secondary processes. It shows average mechanical properties.
Rigid Resin: Its mechanical properties are more developed than transparent resin. It shows properties close to ABS or hardened ABS material used in FDM technology.
Pourable Resin: It is a resin used especially in precision casting applications in the jewellery industry. This resin exhibits improved toughness so that even very fine workmanship can be produced without breaking and volatilizes quickly and without streaks when exposed to high temperature abruptly.
Flexible Resin: They are rubber, silicone-like materials that can stretch thanks to their molecular structure.
High-Temperature Resin: With this material, you can produce details, precise prototypes with high-temperature resistance.
FDM technology offers a wide range of materials and a variety of colours available in engineering grade polymers. The most used among these materials are:
ABS: It is a cost-effective and high strength thermoplastic. Its chemical resistance is low.
ABS+: In addition to the features of ABS, it is more resistant to hush temperatures than ABS.
PLA: It is an organic material based on corn starch. It allows easy manufacturing, and the cost is low.
TPU: It is a medium-strength engineering thermoplastic with high flexibility and durability that can be used in FDM printers.
PET: It is a filament suitable for contact with food, has a powerful bond between the layers, and is used to take prints with impermeability.
PC: Generally, it provides temperature resistance above 110 degrees Celsius; the printed models are translucent.
PC-ABS: A mixture of ABS and PC material that carries the durability and heat resistance of polycarbonates and the flexibility of ABS materials.
PP: Resistant to acid and base solvents. It is a material with high fatigue resistance and excellent impact resistance. It also provides excellent electrical insulation since it has a low coefficient of friction.
ASA: It has good chemical resistance and thermal stability. It has high UV resistance, hardness and high strength values.
PEEK: İt is a semi-crystalline thermoplastic with high mechanical and chemical resistance properties. This material is considered one of the highest performance thermoplastics in the world.
ULTEM: It is a high temperature resistant, translucent and high strength plastic material. Compared to other thermoplastic materials, it has higher dielectric strength and solid electrical properties.
In Which Industries is SLA Used?
In the medical industry
In the jewelry industry
In the moulding industry
In the food industry
In the automotive industry
It is used in applications that require casting and precision manufacturing.
In Which Industries is FDM Used?
It is often used in;
Weapon systems, simulators and electronic product boxes in the defense industry.
Large scale products that need to be produced in one piece
In design tests and fixture manufacturing in the automotive industry.
End-user products and prototypes that are resistant to high temperatures, resistant to chemicals and liquid-tight.
Products for which we produce large volume units and accessories for domestic appliances.
In the ventilation industry
In the education industry.
Low layer thickness, high surface and print quality, ideal for models with complex geometry.
Light sensitive. It can deteriorate under sunlight, has a higher cost compared to FDM, and manufacturing dimensions are relatively small.
Affordable cost, a wide range of materials, the model is ready for use when it comes out of the printer.
High layer thickness, surface precision and smoothness are lower than SLA and may cause problems when printing sharp corners.
In Which Situations Is SLA Technology Preferred?
When intricate details and/or a very smooth surface finish are paramount.
When casting, moulds are to be created to facilitate mass manufacturing.
In modest that need to be transparent
In Which Situations Is FDM Technology Preferred?
On models with a relatively simple design.
In parts needed for prototyping and functional applications
In parts to be used outdoors.
When precision and surface quality are not important
In the manufacturing of large models.
Although FDM provides superiority in terms of pricing and manufacturing time, SLA especially will be better and meet the expectation of producing complex models with its geometry.