FDM vs Resin 3d Printing: Pros and Cons

3D printing and additive manufacturing had evolved over time across various sectors ranging from manufacturing to dentistry, robotics, automotive, and much more. What's more is that the device for this process, a 3D printer, is relatively affordable. Not all printers are the same though, some are relatively more expensive. Asides from the cost, the difference can be in the type of material used for printing.

When it comes to 3D printing materials, there are two major liquid-based materials employed viz resins and thermoplastic filaments. The most common type of 3D printer uses the thermoplastic filament and it is known as Fused Deposition Modeling (FDM) printer.

Resins are basically used with technologies such as Stereolithography Apparatus (SLA) or simply Stereolithography.

In this article, we'll be doing a detailed comparison between FDM and resin 3D printing. This article should be a guide to direct your choice if you're looking into purchasing a 3D printer. Before we proceed, let's take a quick look at the basics of each of these forms of 3D printing.

Fused Deposition Modeling (FDM) 3D Printing

FDM is also known as Fused Filament Fabrication (FFF). At the consumer level, due to the low cost of the printer and printing material, it is the most common type of 3D printing. In FDM printing, thermoplastic filaments -- such as Polylactic Acid (PLA), Acrylonitrile Butadiene Styrene (ABS), Polyetherimide (PEI), Polyether Ether Ketone (PEEK) -- are extruded through a heated nozzle. This melts the material and the resulting molten plastic is applied layer by layer to a build platform. Each layer is laid down one at a time to build the workpiece. The thermoplastic used in FDM is great for many things ranging from children's toys to quick and low-cost prototyping of simple parts.

Resin 3D Printing

The term "Resin 3D Printing" refers to a group of additive manufacturing processes that cure liquid photopolymer layer by layer into solid objects. Resin is used as the 3D printing material. Resin 3D printing is utilized in stereolithography or VAT polymerization printing.

When a liquid material is exposed to light(UV, lasers, etc), it undergoes a chemical reaction that affects its characteristics. This process is called photopolymerization. Photopolymers or light-activated resins are the scientific names for these liquids.

Although, they are simply referred to as resins in 3D printing. Different photopolymerization processes and outcomes exist, but in 3D printing, the one employed is called solidifying. What basically happens is that under the right wave light, a liquid resin transforms into a solid.

The technology type (whether stereolithography or digital light processing) is defined by the type of light source used such as lasers, projectors, and LCD panes. Typically, stereolithography uses UV laser beam while digital light processing (DLP) uses UV light from a projector.

The Pros and Cons of FDM vs. Resin 3D Printing

Now that we've gotten the basics out of the way, let's get down to the crux of the article. What are the benefits or drawbacks that either type of 3D printing may present?

1. Durability of Final Products

One of FDM printing's primary flaws is that its completed items have significant anisotropy or mechanical qualities that are not equal along all three axes. Because of the inherent fragility of the layer-to-layer barriers, filament prints are particularly vulnerable to shear pressures operating in the direction of the layer lines.

In resin-based printing, the curing process improves layer-to-layer adhesion which yields final products with more consistent mechanical qualities across all axes. Resin printing is preferred for engineering components and functional parts because of this feature.

2. Quality and Resolution

The most compelling reason to print using resins rather than filaments is that resin-based 3D printing simply looks nicer. When it comes to quality, resin comes out on top since resin printing is far superior to filament printing.

In FDM printing, the size of the nozzle extruding the filament limits the resolution, but only the size of the laser fired into the liquid resin limits the resolution in resin-based printing. SLA printing uses a powerful and precise laser that counts even the smallest motions, resulting in increased print resolution and overall quality.

Furthermore, resin prints have a satisfyingly smooth surface that can only be attained with some post-processing in FDM printing. SLA 3D printers also have a lower minimum layer height than FDM printers, which helps with quality and detail. While the quality of more expensive FDM printers such as PLA, PETG, and Nylon is still excellent, resin printers are often preferable because resin printing enables finer details to be seen.

Using an FDM 3D printer to attain the same printing standard would necessitate an increase in printing time, resulting in greater prices. Resin-based printers may end up capitulating on this edge in the not-too-distant future.

3. Printing Speed

When compared to printing with a filament, the resin printing process is much faster. The extruder in an FDM printer must move around the print bed to deposit the molten filament in layer by layer in the desired patterns. Because of the weight of the extruder and the controlled method in which the filament must be extruded, this is a slow operation.

There are no such concerns with resin printers. In SLA printing, a single laser beam is rapidly reoriented to point at liquid resin in pre-defined patterns.DLP printing cures an entire layer in a single step, it is much faster. As a result, resin printers are preferred by fast-paced industries.

4. Ease of use and post-processing

Resin 3D printing is usually a lot messier than thermoplastic filament 3D printing. As a result, the latter is typically advised for novices. Resin printing demands a significant amount of effort, particularly when removing your resin model from the manufacturing platform.

Furthermore, if you want your prints to have that professional-grade polish, you'll need to post-process them, in both FDM and resin-based printing. Support structures must be removed, flaws must be smoothed or polished away, and the appropriate paint must be applied.

The messiness of a resin print's post-processing is the biggest turn-off. If you're eliminating the support structures, you'll have to remove them before the post-curing process because the supports are still soft and easy to remove at this point. You'll also need some isopropyl alcohol to remove the excess resin from the surface of your finished print. A safety precaution to take for this process involves putting on some gloves and lining your desk with plastic sheets.

FDM printing, on the other hand, allows for composite printing, removing support structures is significantly easier. Despite the fact that filament prints have a lot more defects, the sanding and polishing procedure is rather straightforward. There will be a lot of elbow grease required, but it will be clean and simple.

The massive mess that the post-processing procedure of resin prints creates can be quite discouraging.

5. Cost

Resin printing is more costly in terms of both the printer and the raw supplies. The price of liquid resin is likewise quite high. For $5, you can acquire a spool of PLA or ABS filament, but it'll only be enough to make approximately a liter of liquid resin. To fill the resin vat, you may require several liters, depending on the printer model.

While a desktop-scale FDM printer can be purchased for around $300, the cheapest resin printer available today costs more than $1000. If you want to get one of the most popular models, expect to spend around $3000.

When printing with resin, the issue is that you have to fill the entire resin vat each time you start a project. Even though the emission of UV radiation to the resin vat is well controlled, the process is far from ideal. Some of the unused resin would have inevitably gone through a premature curing process. As a result, the amount of wasted resin that may be recycled is limited.

6. Composite Prints

In resin-based printers, a project must be printed in a single vat of resin to ensure that the material is consistent throughout. This limits the number of design options available and also makes post-processing a little more difficult.

High-end FDM printers can include numerous extruders, allowing for the creation of prints using a variety of filament types. This is especially handy if you're printing a model that requires support structures, as some materials are more suited to supporting structures than others. PVA filament, for example, can be easily removed by immersing the completed print in water.

This is not a benefit of resin-based printers.

7. Safety

Both resin and filament can be hazardous to one's health and safety. Toxic gases are released during FDM 3D printing, and high temperatures are used. Resin 3D printing has the potential to emit fumes and cause unanticipated chemical reactions. Both types of 3D printers should therefore be used in well-ventilated areas. Additionally, you should invest in a good filtration system to reduce the danger of skin irritation and long-term respiratory problems. Additionally, always use Nitrile gloves and safety glasses when handling uncured materials to protect your eyes from harmful chemical by-products.

Conclusion

You've been provided with the various pros and cons of both FDM and resin 3D printing with respect to specific qualities in this article. This should be a guide to know which is more suited for you based on your experience or what you want at the end of the day.