Fused Deposition Modeling (FDM) is a printing technology that contains a strand of material that gets deposited in layers for creating a 3D printed object. At the time of the printing, the plastic filament has to be fed using a hot extruder which allows the plastic to become soft for precisely placing it in the print head. After the filament melts, it is deposited each layer at a time in the print area for building the masterpiece.
There are several options available for FDM 3D printers in the market, and you can avail them on the basis of your budget. They all start from a few hundred US dollars. Filament spools are known for being relatively inexpensive because they start from $25/kilogram. There are some of the factors that make FDM printers quite popular among people, be it home users or makers.
On the other hand, Stereolithography Apparatus (SLA) works in similar to FDM, but there is an extra method present. In this technology, models get built from one layer to the other. SLA makes use of curable photopolymer, also called liquid resin, that can be hardened using UV light or focused light. The method is known as curing.
These printers are known for building models from the top part to the bottom where the build platform helps in lifting the model upwards, outside the resin bath. The source of light can be a digital projector or laser. The technology used here is known as Digital Light Processing or DLP.
FDM and SLA – Compared
Laser SLA printers are known for being slower as compared to DLP models as they have a smaller surface for the laser beam. In case of DLP printers, every layer hardens soon because the while image of a layer gets projected on the resin. DLP projectors are considered reliable as well as easy to maintain as compared to customised laser systems because the projectors make use of similar technology as seen in home cinema and business projectors. However, the printed models will have to go through the post-processing process.
All in all, SLA machines can be less-budget friendly than its FDM 3D printer counterparts. Resin printers will need a professional context, even though the prices are lowering since the last few years.
Colours and Materials – FDM printers are known for using ABS, PETG, and PLA filaments. They also handle TPU, PVA, nylon, and several kinds of PLA bends (carbon fibre, metals, ceramics, mixed with wood, etc.). Filaments can be found in so many different colours. Some manufacturers are known for offering a service for manufacturing RAL colours when demanded.
Most of the FDM printers make use of standard filament rolls, available in two sizes (2.85mm and 1.75mm in diameter) using various sources. A few of them utilise filament boxes and proprietary filaments – they can be more expensive typically as compared to standard rolls but are known for their better quality.
SLA printers have only limited options in resin materials. In most cases, they are proprietary and can’t be exchanged from one printer to the other. The colour choices are also not very varied. For example, you will be able to buy resin filament Formlabs in clear grey, white, and black hues.
Smoothness and Precision – The resolution of the FDM printers is a factor of the precision of the movements of the extruder and nozzle size. Many factors can influence the smoothness and accuracy in these printer models. Because the bonding force in-between the layers can be lower as compared to the SLA printing, there could be many printing problems (like lower parts shrinkage, shifting of layers, misalignment of layers, warping, etc.). They can significantly compromise the surface smoothing and precision.
SLA printers, on the other hand, are known for producing high-resolution objects that are way better and accurate as compared to FDM printers. It is because the resolution is determined using the optical spot size of the projector or laser, and they can be minimal. As there is less printing force, the surface is a lot smoother. SLA printers are also able to show details that FDM printers cannot produce.
When it comes to fine details, it is better to go for the SLA printers. It is one of the primary reasons why people consider going for the SLA printers.
Both the printers have their pros and cons, and you must be aware of them. If you want a smooth finish and high precision with little importance for the cost, get an SLA printer. If you think the price is essential, try out the FDM printer.