3D Printing, a form of additive manufacturing is a versatile processes used to create solid 3D objects from digital files. Today, Stereolithography (SLA) and Fused Deposition Modelling (FDM) are two of the most widely used methods for 3D printing, allowing for continuous piecing of successive layers of a desired material together until a physical object that is the exact iteration of the digital file is formed. 

Both FDA and SLA deliver on design flexibility, precision, detailing and accessibility. However, there are a number of differences in the processes themselves from how the printing material is handled to how the final product is formed. 

The FDM and SLA Process 
The FDM and SLA processes are dissimilar. In SLA, an ultraviolet laser continuously traces each layer of the object, causing the photosensitive resin layers to come together, harden and form polymers that make up the body of the desired 3D shape. The process of hardening a liquid resin with the use of UV-light is referred to as curing. With FDM, the thermoplastic is melted, fed through the extruder to the print head and deposited layer upon layer until a 3D shape is formed.

FDM VS SLA Compared – Materials 
Owners of FDM printers will enjoy flexibility with materials and colors. FDM printers can work with ABS filaments, PETG or PLA. They can also handle PLA blends, TPU, nylon and PVA. FDM printer filaments are also available in an array of colors. FDM filaments are extremely versatile allowing for multipurpose applications. The hardware itself also allows for customization to accommodate the specifics of several materials. 

SLA printers have more limitations compared to FDM. There are only few choices of colors to be used and there are more limited resin options. The resin materials are often times not inter-usable between printers of different brands. SLA resins, however, offer more durable and industry-grade materials. Resins may be dental, flexible or even heat-resistant. 

FDM VS SLA Compared – Precision and Smoothness
Nozzle size plays an important role in the smoothness and precision of a 3D print. In SLA printers, 3D designs are the subject of great accuracy and precision. The objects are also of higher resolution and greater accuracy compared to FDM printers. This is because SLA printers have very small optical spots and utilize lesser force in creating the model. As a result, the finish is smoother than an FDM process where the bonding force between the layers is lower. FDM printers usually face some printing problems which may include layer shifting, misalignment or shrinking of lower parts. 

SLA 3D prints can boast of resolutions as little as 25 microns which make their appearance highly accurate and resembling of injection molded parts. SLA prints also come with tighter tolerances, making it extremely desirable for medical implants, jewelry posts and aesthetic architectural models. 

FDM VS SLA Compared – Postprocessing 
Post-processing generally refers to the processes that may be carried out after the physical 3D print has been obtained. After printing on FDM printers, you will need to get rid of the supports and excess plastics around your print. FDM printers also tend to have adhesion issues; this is when the printed object sticks to the print bed. 

SLA printers will pose similar challenges. Post-printing, it can be quite challenging to remove the object from the print platform. You are also likely to encounter sticky resin remnants that has to be removed using some isopropyl alcohol (this should be done with protective rubber gloves). In both FDM and SLA Printers, the meticulous use of a palette knife will help get your 3D print off the print bed or platform. Excess plastic in FDM prints may be removed by sanding. 

According to website Carbon3D, newer solutions for the sticky SLA resins also involve using oxygen to create a “dead zone” around the printed model. This will prevent the resin that is at the surface of the object from hardening. 

FDM VS SLA Compared – Printing costs

SLA Printers will typically cost you more than FDM printers. In SLA printers, there are many consumables. The resins alone will cost anywhere from $80 to $150. The resin tank of an SLA printer will likely need to be replaced after printing some 2.5 to 3.0 litres. This is because after a number of uses the light source will be unable to accurately project the image into the resin. Resin tanks may cost around $30 to $80. The build platform will also become marred after a number of uses. This might set you back another $100 when it becomes due for replacement. 

FDM models on the other hand are less expensive to print and maintain. In Fused deposit model printers, the filament rolls and nozzles are the main consumables. Today, 1KG of PLA filament may start from as little as $25, while special-purpose filaments would be on the higher ends. 

FDM VS SLA – Conclusions 
FDM and SLA both offer various advantages and disadvantages. As these two techniques are the most commonly used in 3D printing, the best course of action is to first decide on the job requirements. SLA remains the best option for creating finely detailed 3D prints while FDM is more suitable for rapid prototyping parts where precision and smoothness isn’t crucial. FDM is also more affordable and great for building low-cost models. 

SLA is excellent when strength and durability is not crucial and perfect for creating 3D prints where intricate, smooth surface finish and attention to details is crucial. 

FirstPart 3d rapid prototyping services
You don’t have to buy a 3D Printer! With this option, First Part offers professional 3D printing service that allows you to get anything printed without incurring the cost of a printer. 

FirstPart professional 3D printing services is an advanced manufacturing process that has been developed over the years to ensure perfection in every project. Our qualitative 3D printing guarantees quality-generous fabrications that are superior, rigid and functional right from the start. From speed to quality, design, waste minimization and diverse applications with a wide array of materials, we are your one-stop-shop in China for rapid 3D printing services for small and large-scale projects.