How to Choose a 3D Printer? Comparing FDM, SLA, and SLS 3D Printing Technologies
Time Cost Assessment for Technological Stages of 3D Printing in Different Technologies
Compared to outsourcing to service providers or using traditional tools such as machining or injection molding, in-house 3D printing can save weeks when producing single prototypes or custom parts.
But when it comes to choosing the fastest 3D printing technology, technical specifications and raw printing speed do not give the full picture for an informed choice. You also need to consider how much time it will take to set up the print and post-process the parts to achieve the desired results. To choose a 3D printer, you will need to compare these parameters. This will help you find the technology that offers the right balance between time and productivity.
Let's compare the workflows for the most common 3D printing technologies: FDM, SLA, and SLS.
1. Print Setup
Regardless of the technology used, 3D printing involves two main steps. These are the setup of the file with the 3D model to be printed, and the actual printer setup.
During the file setup process, the user utilizes specialized print preparation software, sometimes called a slicer. Before sending the design to the 3D printer, parameters such as support structures, part orientation, and print resolution are selected in this program. By printer setup, in the context of this article, we mean the process of getting the printer ready to start printing by loading, changing, or refilling material, and replacing the tank or cartridge if necessary.
Let's look at the setup process for each technology, starting with FDM. FDM 3D printing has more design constraints than SLA or SLS, especially with complex parts, which may require more work to optimize CAD models before printing. On the other hand, setting up an FDM printer is, in most cases, quite simple, and changing the material takes only a few minutes.
SLA printing has fewer design constraints, and file preparation for printing takes only a few clicks. Preparing an SLA printer for printing is largely straightforward and requires no complex configuration, and changing materials takes only a few seconds.
Since SLS 3D printed parts are supported by the surrounding powder, no support structures are required. This reduces constraints on print geometry. Preparing print jobs is also simple, as the software helps with nesting and optimizing parts within the build volume. The setup workflow for SLS printers and powder recycling may seem complex, but the right post-processing accessories will greatly simplify it.
Comparison of time spent on 3D print preparation using different technologies:
2. Printing Speed
Now let's compare the actual printing time of models. Some printers are faster at printing single parts, while others are optimized for large batches. Therefore, it is important to choose a 3D printer that balances time-per-part and productivity according to your needs.
FDM printers typically do not create solid parts; instead, they create internal structures to fill the space inside the model and save time. They also use thicker, coarser layers, resulting in a trade-off between speed and detail. As a result, an FDM printer is a good choice for rough prototypes, but it is slower at producing complex parts with fine detail.
SLA 3D printers represent a "sweet spot" for versatility. They are best known for creating waterproof functional parts with smooth surfaces and fine details. With some new materials, they represent the fastest technology for creating quick rough parts with thicker layers for rapid prototyping. The printing time for each part also decreases rapidly when you add many parts to a single build. Thus, SLA is often a good choice for printing large batches of parts. For those looking to print with higher productivity, this can be a major advantage.
The SLS 3D printing process typically takes longer because the printer needs to preheat, and the printed model also has to cool down slowly after printing. However, the SLS process allows for nesting many parts into a single build. This, in turn, can often be the most efficient way to produce large batches of parts, when post-processing and finishing are taken into account.
Comparison of time spent on 3D printing small, medium-sized parts, and multiple parts simultaneously:
3. Post-processing
Processing parts after 3D printing is something most manufacturers don't talk about. However, it heavily influences the design and takes some time in the workflow.
Post-processing of FDM parts can be fast, but only for simple parts and rough prototypes. More complex parts require the creation of support structures that are broken off during post-processing. If the support structures are printed from special materials, they require dissolution in water or other chemicals. This depends on the material from which they are printed. Achieving a high-quality finish on FDM parts requires extensive manual sanding and finishing. This can significantly affect dimensional accuracy, form, and fit of the parts.
Post-processing for SLA parts consists of washing the part and, depending on the material and design, also subsequent curing and support removal. Washing and curing can be automated with special accessories to save time. Thanks to the thin design of contact points, supports are removed quickly, providing high-quality service immediately after printing. Overall, this leads to slower post-processing compared to FDM for simple parts. The situation is different for high-quality parts with complex detailing and thin structures. For SLA, processing such products will be faster than for FDM. Complex parts in FDM require the construction of more supports and, accordingly, more complex post-processing.
The powder-based nature of SLS can make post-processing messy and labor-intensive. However, the right accessories can significantly simplify the process. Printed parts must be freed from the powder that surrounds them and excess material must be removed. To achieve the best surface quality, bead blasting can be used. Most importantly, support structures are not printed on every part. Post-processing can be scaled and, overall, is easier compared to FDM and SLA. As a result, post-processing time per part for SLS can be significantly less at scale.
Comparison of post-processing time in different printing technologies:
As we can see, speed in 3D printing is more than just the printer's printing speed. To be able to confidently compare different solutions, it is helpful to familiarize yourself with the entire workflow of the chosen printer or technology and examine them from design to finished part. Time is estimated based on your design and requirements.
This is one of three articles helping to answer the question: How to choose a 3D printer. See also other materials on this topic:
Comparison: FDM, SLA, and SLS. Functional and Visual Characteristics
Leave a Comment