Resin vs Filament 3D Printers (SLA, FDM) – Which Should I Buy?


In the highly advanced world that we live in today, 3D printers and their developments have become diverse. People today are faced with several options to consider when it comes to features, functionality, filament compatibility, mode of technology used, and whatnot.

This article will aim to look into SLA & FDM 3D printing and help you make a decision which to go with. These are the two main comprehensive yet productive methods of 3D printing.

Between resin and filament 3d printing, I would recommend buying a filament 3D printer (FDM) for beginners because it is the easier choice overall and a better entry into the world of 3D printing. Once you gain some experience and want higher quality, then you should go with resin 3D printers (SLA).

Fused Deposition Modeling (FDM) is a common process in which a special material called thermoplastic is first melted at high temperatures and then deposited layer by layer on a platform to form prints of great quality and precision.

On the other hand, Stereolithography Apparatus (SLA) works with the use of a photopolymer or liquid resin which gets cured by UV light. In turn, prints of the supreme quality with ultra-fine detail are produced.

The two methodologies of FDM and PLA are truly extensive. Keep on reading to get a better grip on the concepts since there is a lot more that’s going to follow.

How FDM Operates

Fused Deposition Modeling or better known as FDM, is one of the most common methods of 3D printing that beginners are usually introduced to.

Quite typically, it’s also known as Fused Filament Fabrication or FFF. With the passage of time, this technology has grown leaps and bounds within the realm of 3D printing ever since it was patented by Stratasys, an American-Israeli 3D printer producer, more than 20 years ago.

To the core, it’s an additive manufacturing process and forms the biggest base of 3D printing on a global level.

At best, the process is everything but complex. Through its usage, millions of prototypes have come into existence and that too, in a very short period of time.

So, what it does is basically involve a thermoplastic material and all the magic starts from there. A thermoplastic is a plastic polymer that has unique properties. It becomes pliable or flexible when it’s heated above a certain temperature but solidifies intensely when it’s cooled down.

Therefore, a 3D printer uses this special characteristic of a thermoplastic polymer and makes prints.

At first, the plastic filament is loaded onto the extruder (pusher of material) of the printer, heated in the hotend to a point where it starts to melt, and then extruded out by the nozzle onto the build platform layer on layer.

When the melted plastic cools down, solid objects can then be formed in tiny layers to build a full object. The layers adhere to each other during the print, and constitute towards forming a printed part.

When it comes to the printing filaments, many different types can be used with FDM printing. These include ABS, PLA, Nylon Polyamide, PETG, PVA, and TPU. These are all plastics you’ve already come into contact with, from food containers to legos.

Furthermore, exotic materials such as wood-fill, metal, and glow-in-the-dark filament are possible and possess good capabilities with FDM technology.

Many businesses and industries have opted for FDM printing as their go-to choice for printing objects. What once took a while to produce, now takes a considerably low amount of time.

In this way, FDM tech has provided engineers around the world with effective testing, creation of tools, and commercial prototypes.

From automaker industries to consumer goods manufacturers, FDM has a hand in almost every product to be seen in everyday life. This includes toys for children, sportswear, food and drug packaging, and medical items.

FDM owes its fame and popularity to its cost-efficiency, ease of use, and reliability. It’s one of the most proven methods of 3D printing that’s bound to deliver exceptional results when the application and the methodology used is fairly correct.

How SLA Operates

Belonging to the Vat photopolymerization domain, Stereolithography (SLA) is also an additive manufacturing process just like FDM but with substantial differences. For starters, instead of a thermoplastic filament in FDM technology, SLA’s operation revolves around a curable photopolymer.

The photopolymer is actually a liquid resin that gets cured by light. By curation, it is understood that the liquid resin is compelled to adopt a solid form when an Ultraviolet light (UV) is applied directly to it. Therefore, SLA works by curing resin with the help of UV radiation.

To help understand the phenomenon better, the following are four major components of every SLA-based printer one can observe:

  • A tank that contains liquid resin. This liquid photopolymer is a liquid plastic in nature.

  • A build platform that is engrossed in the tank. To accommodate the printing process, this permeable platform moves upwards and downwards whenever required.

  • An Ultraviolet laser

  • A fully interactive User Interface (UI) which serves as a control system for the printer.

The working is a bit complicated if compared with other common ways to 3D print.

To begin with, prints made are upside-down, therefore the term “Inverted Stereolithography”. It all starts when the build platform is lowered down to the region of the liquid resin tank, so the space between the two is no more than one layer.

Afterward, UV light from the bottom of the resin tank selectively curates the liquid plastic, thereby hardening it and forming a solid part in the layer by layer fashion. The whole procedure occurs recurringly until the printing has finished.

The concept birthed in the 1980s and was entirely restrained to heavy industrial machines until new innovations and intuitive thinking made it land on a printing enthusiast’s workspace today.

A wide range of resins are available to choose from when printing using SLA technology.

These include Standard Resin, Clear Resin, Castable Resin, Tough or Durable Resin, Tough or Durable Resin, High-Temperature Resin, Dental Resin, and Rubber-like Resin.

All of these photopolymers offer their own distinctness, and work as per the user’s needs.

SLA & DLP 3D Printing

Direct Light Processing (DLP) is closely associated with SLA. In fact, the two are regarded quite similar with the exception of one major difference.

The factor that distinguishes one method from another here is the source of light that curates the liquid resin. As we know, SLA involves the use of highly precise UV laser. Unlike this, DLP features the usage of a projector operating below the resin tank which flashes a whole layer at once.

When accuracy and precise detailing is in question, SLA has a definite edge over DLP with the latter being simpler in terms of mechanics along with the point of affordability.

Pros & Cons to FDM Printing

The following are some major advantages of using FDM as well as the unfavourable downsides to it.

The Pros

  • Being tremendously renowned, simple mechanics make FDM printers affordable.

  • FDM technology is recommended for hobbyists and 3D printing tinkerers.

  • Atypically, printing with FDM offers low-cost solutions, and isn’t very expensive as compared to other printing methods.

  • A huge range of thermoplastic filaments are available to be used with FDM printers. All of these offer contrasting and quirky options, and the flexibility in choosing between the plastics cover plenty of ways to print

  • As FDM technology made its way to the 3D printing world, it has opened up doors for rapid prototyping, and true convenience in printing models.

  • Scalability is another great advantage in FDM printing. An easily-scalable design amounts to a favourable cost-to-size ratio.

  • With no geometrical constraints, smaller and larger parts can be printed with delicacy around corners and undercuts. Furthermore, a part’s complex geometry is something that FDM printing can handle well.

  • Given the right printing filaments combined with the right printer, FDM technology is also capable of forming greatly durable, strong, and reliable prints.

The Cons

  • As common and widely used FDM printing con is print quality and detail. As the melted plastic comes out the extruder in layers, the quality is put down to the thickness or layer height of each layer.

  • Due to the difference in adhesion, and similarly cooling between the layers, many printing hassles such as warping and curling are prevalent in FDM printing.

  • Safety issues with heat, burns, scrapes and even fires in some cases
  • FDM printing tends to be a lot louder, but there are more solutions to make your printer quieter
  • There are a lot more individual parts to tinker with so more things can go wrong

Pros & Cons to SLA Printing

Now that we know the ins and outs of FDM printing, the following is why SLA is preferable at times, and why it’s best to be avoided.

The Pros

  • SLA printing and the best quality prints with intricate designs are two synonymous concepts. The use of a laser projected operation paves the way for superb precision.

  • With terrific dimensional accuracy and the formation of convoluted details with ease, SLA-based printing is recommended when quality is above anything else.

  • For the manufacture of visual prototypes, SLA technology does a great job with the provision of ultra-smooth finish.

  • With the availability of clear, castable, and flexible resins, the options are appreciable with this photopolymer-based printing method.

  • The layer thickness can go as low as 25 μm (0.025mm) . Moreover, the least sizes of features range from 50-250 μm.

  • SLA printing can also accompany mass-production when casting by creating molds.

  • In the process of SLA printing, curation is involved. The curing of the plastic layer by layer is a much more compact method of print formation that provides constant mechanical properties to all three axes of the part.

  • Industry-wise, SLA machines are capable of printing enormous prints that can measure up to 1500 x 750 x 500 mm.

The Cons

  • Printing can take some time with SLA, but the process is being sped up over time

  • Support items are most often a necessity when printing using a resin-based printer.

  • In addition, post-processing is also required if one wants to eliminate any leftover marks on the print from SLA printing.

  • Prints made out of liquid resin won’t be highly durable. Additionally, it has been reported that constant exposure to sunlight will deteriorate the parts over time.

  • The fragility of SLA printed parts makes them unsuitable to be represented as a functional prototype or for mechanical assessments.

  • The costs associated make Stereolithography a big turn-off for many. Relatively, SLA is expensive when the machine itself and the needed materials are put into consideration.

  • Resin-based printers do not offer versatility if one wants to print with different materials. Parts are always made from a single vat of resin as that’s the best an SLA-based printer can do.

  • The world of Stereolithography is small-scale as compared to the community of FDM technology. The availability is lesser, and the already existing options are costly.

  • When it comes to ease of use, SLA printing could get very messy. The residue of the resin is a hassle that needs attending to with a palette knife. Afterwards, the print itself could use a wipe of isopropyl alcohol to wash off any unnecessary layer of resin on the part. All these basic steps are equivalent to post-processing in FDM.

A Direct Comparison of FDM vs SLA

To distinguish between FDM and SLA in more depth, we are next going to draw a comparison between the two technologies regarding different aspects.

The Cost

Although 3D printing is overall expensive, we can narrow the differences down by estimating how much FDM and SLA can make you dive into your pockets.

There are terrific FDM 3D printers out there that are budget-friendly, and perform really well, starting from $200 and such. Furthermore, the cost of the thermoplastic filaments is on the decline recently. A spool of PLA costs around $25 at best.

SLA printing can get quite expensive, but as the SLA market has become more saturated, more manufacturers have been producing machines. You can get a solid budget SLA 3D printer for around $250 which still prints great quality. Most people wouldn’t touch SLA printing because it used to be so expensive, so times are changing.

In terms of resin, I’ve seen 1KG of resin as cheap as $25, when it used to be upwards of $40-$50 so the costs aren’t too far off anymore.

The resin tank on the other hand, has to be replaced from time to time. This is because the tank gets smeared after constant use, rendering the UV light useless in curation.

Furthermore, the build platform needs to be substituted with a new one as it can get spoiled with print removal over time. A brand new print bed can be bought for around $50 depending on what brand it is.

Post-Processing and Ease of Use

In the aftermath of a part printed with FDM technology, support items can be removed either using your hands or a handy knife. The process of sanding is also a great help in refining prints.

SLA printed parts, in other news, are usually engulfed with sticky resin that needs to be brought in contact with isopropyl alcohol. This is a reason why SLA printers often pack rubber gloves with them for protection purposes.

You’re gonna have to get a lot more active when it comes to resin printed parts, but filament prints can also be quite tedious when it comes to removing supports. Resin supports come off pretty easily for the most part, because the material isn’t as tough as filament.

There are ways to make supports easier to remove so it isn’t too much of an issue.

Quality

The most important aspect regarding 3D printing is quality. With the layer by layer printing in FDM along with their respective adhesion, prints are bound to look great, no doubt, but nowhere near what SLA delivers.

Using a highly-refined beam of UV, the precision is second to none of the parts printed with SLA. The added detail lends astounding detail, and amount to visually stunning results.

FDM prints are great for speed and larger objects but you tend to be able to see the layer lines and see print imperfections such as ringing, warping and gaps in layers. You don’t get many print imperfections in SLA prints so you’re getting consistent high quality prints for a slight increase in price for the materials.

Best FDM Printers

To accommodate the reader more, the following are two of the best 3D printers that use the enthralling technique of FDM. A description of these printers is provided alongside so the key benefits could be known.

Creality Ender 3 Pro

Creality is one of the world’s leading 3D printing brands that have outdone itself in terms of producing the most capable machines.

Priced at just under $300, this China-based manufacturer’s Ender 3 Pro is a printer that packs immense value. Being multi-faceted, this magic machine from Creality is something for beginners and experts alike.

The Ender 3 Pro comes almost ready out the box and requires minimal effort to calibrate and set up initially. The process is well-explained in the instructions manual and beginners can easily make their way to building the machine successfully. Only the Z-axis needs to be fine-tuned as the X and Y-axis arrive set beforehand.

What takes the cake is the amazing affordability of the Ender 3 Pro. Its shockingly low price tag is what makes many people get it at first glance, but that’s not all though.

The Ender 3 Pro contains many features one wouldn’t find even in an expensive printer such as a build capacity of 220 x 220 x 250 mm, a magnetic print bed that makes print removal a breeze, auto-recovery, and a constricted filament pathway.

The design of the Ender 3 Pro makes it a sturdy machine with rubber feet to keep it in balance. The frame is developed with aluminum extrusions combined with improved bearing wheels for increased dimensional stability.

The printing platform of the Ender 3 Pro is heated as well, making warping and curling less likely to happen.

The “C-Mag” magnetic printing bed is what enables the Ender 3 Pro to offer true ease to its users. Prints can be removed with flexibility, and the striped surface of the bed helps the first few layers adhere critically better.

Using the timeless FDM technology, the Ender 3 Pro works well with a variety of thermoplastic materials, and makes prints of great, if not perfect, quality.

QIDI Tech X-Plus

The X-Plus from QIDI Tech is a fine embodiment of top-notch printing. From the ground up, it has been made with the inspiration to deliver amazing results.

Although it will cost you around $1000, it’s going to offer a lot more than that. Harnessing FDM technology to its very core, it supports a wide variety of filaments such as ABS, PLA, TPU, and even high-temperature filaments such as Nylon, and PC.

Arriving at your doorstep with a dual extruder and two separate compartments for filament entry, the X-Plus is a quality machine you can rely on.

The printing platform built in the X-Plus has two alternate sides to it, so users won’t have a tough time with optimizing and changing thermoplastics on the go.

The X-Plus also contains an enclosed print chamber that allows to keep the heat inside managed, and reduces the chances of warping. Moreover, a perfectly heated environment provides prints with the balance they need in order to adopt a smooth visual appearance.

The build volume is 270 x 220 x 200 mm, quite extensive, and attributes to the capacity of making larger prints. The quality of the print might usually suffer in this case, but not with the X-Plus as it maintains its original standard of greatness regardless of how big of a part you need to print.

To top it off, despite being loaded with features, the X-Plus is user-friendly, and doesn’t bother much when setting it up.

Best SLA Printers

The following are two highly celebrated resin-based printers that have made their way to splendid appraisal.

Anycubic Photon S

Released in 2019, the Photon S is an SLA printer that has made its mark quite proficiently on the market.

The company hailing from Shenzhen, China is famous for producing capable machines. The Photon S being an example, is pre-eminent with its truly reasonable price, and the supreme quality of prints that it makes.

Being budget-friendly, the printer is going to cost you around $500, but will deliver much more.

Compatible with a multitude of 405 nm resins that offer different options to choose from, the printer uses the curation of these photopolymers to provide an excellent printing experience.

Absent in the original Anycubic Photon, the Photon S arrives upgraded with a sturdier Z-axis coupled with two liner rails for a smoother operation. Moreover, the overall stability of the Photon S is also improved as compared to the default Photon edition.

ELEGOO Mars

One of the most inexpensive SLA printers out there, the ELEGOO Mars is a consumer-grade machine costing just under $300.

Starting off with the design, the build of the printer is quite commendable with an aluminum body reinforced with a matte finish. You could tell that you’re at home with a premium device just by the feel of it.

The whole procedure with the Mars is as simple as it gets. In turn, it offers you elite-class prints.

Being a cut above its rivals, with the price it’s purchased, the ELEGOO Mars is extremely difficult to avoid.

The ease of use is unparalleled here keeping in mind that it involves the technology of SLA, which can generally get messy.

Similar to the Photon S, Mars is also compatible with 405 nm resins, making it offer the same versatility when choosing between various photopolymers.

Verily unforgiving, this printer comes off nothing but a steal due to its performance, the ease associated in operation, and the superb quality of prints that undergo production as soon as you start with the ELEGOO Mars.

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