3D printing has revolutionized the manufacturing industry by providing a quick and cost-effective solution to produce complex parts, especially in smaller volumes.
Different types of 3D printers use various feedstock materials to create their final products.
The most common consumer-grade 3D printers use the Fused Deposition Modeling (FDM) process to print with thermoplastic filaments, and Photopolymer-based printers use resin materials.
In the FDM process, filament is purchased in spools, and the spool is typically mounted onto the printer, where a geared extruder of some kind pulls the filament into the hotend, where it is melted and then extruded layer by layer onto a buildplate, building up a 3D part.
Resin printers, such as SLA, DLP or LCD-based systems, print by using light to cure photopolymer resins.
In these cases, the resin is poured into a vat connected to the printer, and the build plate is lowered into the vat. The light source cures one layer at a time, and then the build plate is raised/lowered by one layer height, and the next layer is cured.
Both types of printers have their advantages and disadvantages.
In this article, we will be taking a look at both resin and filament type systems, to give you an overview of the differences between them, and to help you make a decision which type of printer is right for you.
Characteristics of Resin for 3D Printing
Photopolymer resins are a type of liquid resin that solidifies when exposed to light. These processes use light to cure the resin layer by layer, creating a 3D object.
The resin is sensitive to specific wavelengths of light, causing it to harden and form the desired shape.
Printing with resins offers high resolution, fine details, and smooth surface finishes.
Resin printers come in all shapes and sizes (and price-points) starting with LCD-type and SLA-type printers at the lower end of the price range, going up to DLP printers at the higher end.
Advantages
- High resolution: Resins can produce parts with intricate details and sharp edges, making them suitable for creating intricate models, miniatures, prototypes, and dental restorations.
- Smooth surface finish: Resins provide smooth, glossy, and seamless surface finishes that are ideal for visual or aesthetic applications.
- Strong materials: Advanced resins have high toughness and strength, making them ideal for functional and engineering applications.
- Wide range of materials: Resins can be customized to offer different properties, such as flexibility, transparency, and color.
- Fast printing speeds: SLA technology allows for fast printing speeds, making it suitable for time-sensitive projects. Advanced resin processes such as CLIP-based DLP systems from Carbon3D are incredibly fast.
Limitations
- Cost: Resins can be more expensive than other 3D printing materials such as thermoplastics, and require specialized equipment to use.
- Sensitivity to light: Resins are sensitive to light and can deteriorate over time if not stored correctly.
- Limited size: Resin printers typically have a smaller build area compared to other 3D printing technologies, making it unsuitable for large-scale projects.
- Post-processing: Resin-based prints typically require post-processing such as cleaning, curing, and finishing, which can be time-consuming and increase overall costs.
- Health and safety concerns: Resins can release fumes during printing and can be harmful to human health if not handled properly.
Characteristics of Filament for 3D Printing
Thermoplastic 3D printer filaments work by using heat to melt and deposit material layer by layer to create a 3D object.
The process is called Fused Deposition Modeling (FDM) or Fused Filament Fabrication (FFF).
The filament is fed into a heated extruder, melted, and deposited onto the build platform to create the desired shape. The material then solidifies as it cools, creating a solid structure.
FDM / FFF offers strong and durable parts, and a wide range of material options.
Advantages
- Affordability: Thermoplastic filaments are relatively inexpensive compared to other 3D printing materials, such as photopolymer resins.
- Wide range of materials: Thermoplastic filaments are available in as variety of materials, including PLA, ABS, PETG, Nylon, and TPU, each with its own unique properties.
- Strong and durable parts: Thermoplastic filaments can produce strong and durable parts suitable for functional and engineering applications.
- Large build volume: FDM technology typically has a larger build volume compared to other 3D printing technologies, making it suitable for larger-scale projects.
- Easy to use: FDM technology is simple and user-friendly, making it suitable for beginners and hobbyists.
- Recyclable: Thermoplastics can be remelted and recycled. There are plenty of recycled filaments on the market also.
Limitations
- Lower resolution: FDM technology typically produces parts with lower resolution and visible layer lines compared to other 3D printing technologies, such as photopolymer resin-based processes.
- Requires support structures: While resins also often use support structures, resin supports are printed very quickly, while FDM supports take much longer.
- Prone to warping: Some thermoplastic filaments, such as ABS, are prone to warping and cracking during printing, especially when printing large objects or objects with a large surface area.
- Poor surface finish: FDM technology often produces parts with stepped, rough, matte, or grainy surface finishes, which may not be suitable for visual or aesthetic applications.
Resin vs Filament for 3D Printing
| Side by side comparison | FDM | RESIN |
|---|---|---|
| Cost | ☑️ | |
| Ease of use | ☑️ | ☑️ |
| Resolution | ☑️ | |
| Surface Finish | ☑️ | |
| Speed | ☑️ | |
| Application | Bigger objects Strong parts | Smaller objects Detailed parts |
Let’s have a look at how resins compare to filaments on some key metrics.
Cost comparison
At the consumer end of the scale, you can get filaments extremely cheap.
Some vendors online will sell you 1 kg roll of PLA filament for around $10 USD if you shop around on the internet.
For low-cost resins, you can expect to pay around $30 per kilogram.
At the higher end of the scale, both engineering grade filaments (such as ULTEM) and specialist resins (such as those from 3DSystems) can run into multiple hundreds of dollars per kilogram.
Verdict: When it comes to low cost feedstock, filament wins on price.
Ease of use
This is a tricky one to gauge, because when both filaments and resins are used properly, on well-configured machines, and the materials are stored correctly prior to use, then they are both relatively easy to use.
For a filament, if all is going well, you just load it onto the printer, feed it into the extruder, and it prints.
The same goes to resins – you just pour it into the vat, and as long as the bed is aligned, it will print fine.
But then, life is never so easy. And if the materials are stored incorrectly, or if the bed isn’t aligned, or if you get a tangle on your spool, then you can have print failures, and lose time and money.
Verdict: When both are stored properly, and assuming that the user has done everything they can to ensure a successful print, we would say that resins have the upper hand in terms of ease of use.
Because even if the user has done their best to follow the correct procedure, they can’t do a thing to stop a filament from sticking to the spool if it’s been wound onto the spool incorrectly in the factory.
Some things are just out of the users’ hands, and this is one of them.
Resolution
Creality Ender 3: reddit.com by CgManuil
Creality Halot One: twitter.com by Daniel Clark
This one is a no-brainer really.
A $200 FDM printer (such as the Creality Ender 3) will provide accuracy in the XY direction of around 100 microns, but a similarly priced resin printer (such as the Creality HALOT One) will provide XY accuracy of up to 10 microns.
The movement in the z-axis tells a similar story.
The layer height on an Ender 3 can go as low as 0.04 mm (40 microns) because that is the height travelled when a single step is turned on the stepper motor.
But nobody prints at that resolution on an FDM because it would take forever to print just 1 mm in height.
Typically, a 200 micron layer height is used for the best combination of speed and quality. And even then, the quality is not amazing.
The HALOT One (and other resin printers) have no such issue, though.
Because each layer is printed quickly, lower steps can be used on the z-axis, meaning a higher resolution print can be achieved in that axis in a reasonable time.
Some have reported going as low as 10 micron layer height on these low-cost resin printers, although Creality recommends a minimum layer height of 30 microns.
Verdict: Whether it’s the Z-axis or the XY-axis resolution, even 200 dollar resin printers have resolutions at least an order of magnitude better than an FDM printer that costs 100x the price. Resin wins here.
Surface Finish
When printing on FDM, the larger layer height produces stepped artifacts on the surface of the print. This is particularly noticeable on curved parts.
On parts with flat vertical faces, the steps are not really a problem, but the layer lines are. Sure, this can be fixed somewhat with vapor smoothing, flame polishing, or a lick of paint, but coming right off the printer, FDM has a fairly poor surface finish by definition.
Resin printers can create parts with fairly exceptional surface finishes, bordering on an optical finish. This is due to a combination of the high resolutions allowed by resin printing, and also by the effects of the light curing process, which softens the layer lines a little bit.
Verdict: Without relying on post-processing trickery, resin wins here, hands down.
Final Verdict
Resin printers are a great way of creating highly detailed parts for very little money.
But while LCD printers are very cheap, the low-cost resins are around about 3x more expensive than low-cost filaments.
Printing with resins also limits the build size somewhat, at least at the consumer-grade level. If you want a BIG resin printer, it will cost you many thousands of dollars. And it will cost you a few bucks to fill the resin tank, too.
So in terms of printing large parts, printing with filament offers the best value, although at the expense of surface finish, and potentially print speed.
It’s hard to say that one is “better” than the other, because it all depends on your budget, and what you want to use the part for.
Remember, that thermoplastics melt, and thermoset plastics (resins) do not. So resins have a higher thermal stability.
And that said, there are also thermoplastics that have high HDT (heat deflection temperatures) meaning they can survive stress in hot environments without bending too much.
These materials are not cheap at all, but then neither are resins with high HDT values.
So without going too deep into the world of engineering plastics (which are in a league of their own, and are beyond the capabilities of your average $200 3D printer), when looking to decide which feedstock you should print with on a consumer printer, you should consider the size of the parts you are designing, the surface quality, and the strength.
If you want big, strong parts, but don’t mind taking a hit on surface finish, FDM should be fine for your needs.
If you want to print smaller parts, that may not need high strength, but surface finish is important, then resin should be your choice.