What Is Resin 3D Printing? Resin vs FDM: Which Is Better!


FDM (Fused Deposition Modeling) printing is by far the most used 3D printing technology. In a recent survey on 3D printing, 71 percent of respondents said they used FDM printing. Resin printing is the third most used technology after selective laser sintering (SLS). 

Resin printing consists of three main printing processes, namely stereolithography (SLA), digital light processing (DLP) and masked stereolithography (MSLA). All these processes use light to harden or “cure” a liquid resin and produce a 3D print. SLA uses a laser, DLP uses a projector and MSLA uses liquid crystal display (LCD) as the light source.

Here is a video on how Resin Printing Works,

In the past, resin printing was exclusive to large companies with skilled technicians as resin printers were large, complicated and very expensive machines. Today, resin printing is more accessible as desktop resin printers have become smaller, simpler and of course cheaper.

But what makes resin printing different from filament printing? Which produces stronger parts and are there any specific applications where you should choose one over the other? In this showdown we compare filament and resin as well as FDM and SLA printers to see which comes out tops. 

Is FDM or SLA Stronger?

When comparing 3D printing technologies, both SLA and FDM produce strong parts. SLA has the advantage of producing isotropic parts whereas FDM parts can be weaker due to anisotropy. 

Isotropy In SLA

Isotropy simply means that the properties of a material are the same regardless of direction. With regards to SLA, this means the mechanical strength of resin-printed parts is the same along the X, Y or Z planes of that part. 

Anisotropy In FDM

Anisotropy means the properties of a material are dependent on the direction. For example, wood is stronger with or along the grain than it is against the grain. The same applies with FDM printed parts which are not equally strong in all directions. Source

This is why printing with FDM has to take into account the direction in which the part will be loaded. This will determine how much weight or force the part can handle. If oriented the wrong way, the part has a high chance of failing. 

Isotropy is the main advantage SLA has in terms of strength. It is also worth noting that material bonds at a mechanical level when printing with FDM. In SLA printing, the liquid resin bonds at a chemical level. This produces a stronger bond. Source

Is Filament Or Resin Better?

Filament is the raw material used in FDM printing whereas resin is used for resin printing processes including SLA, DLP and MSLA. The biggest advantages filament has is that it is easier to work with and much cheaper than resin. 

What Is Filament?

Filament is a thermoplastic. It melts but does not burn. Instead it hardens when it cools in a reversible process known as fused deposition modeling (FDM). The most common types of filament are PLA, ABS and nylon.

Strengths

  • Filament is much easier to use. Rolls of filament are fed through a print head that melts plastic onto a build plate. 
  • It is safer to handle. Resin is toxic when it comes into contact with the skin.
  • It is more versatile. There is a wider choice of materials when working with filament than there is when working with resin. This includes glow-in-the-dark, conductive, wood and metal filament for example.
  • Filament is cheaper, costing as little as $15 per kilo.

Weaknesses

Filament easily absorbs water and becomes weaker when wet. 

What Is Resin?

Resin is a thermoset liquid polymer that solidifies when exposed to light. This is through either SLA, DLP or MSLA which are non-reversible processes. The most common resins are standard resin and clear resins. 

Strengths

  • Resin excels in producing transparent prints. 
  • Much better for producing high resolution prints.

Weaknesses

  • Resin is generally more expensive, with the lowest cost resins costing an average of $40 per liter. 
  • Much more difficult to use as resin always requires post-processing unlike filament which can be used without any post-processing.
  • Narrower choice of resins to print with. 
  • Resins are usually specific to a type of printer. You cannot switch resins between printers.

Is A Resin 3D Printer Better Than A Normal 3D Printer?

The application is possibly the most important consideration when comparing resin and FDM printers. For example, resin printers are better for producing detailed prints. FDM printers are better for printing a large volume of prints. 

Resin 3D Printers

The biggest edge resin printing has over FDM printing is it produces parts with better accuracy or truth to detail. Resin printing is indisputably better for creating anything with high resolution. Resin will give you a smoother finish than anything achievable on an FDM printer. 

There is less force applied on the print due to stacking of layers as with FDM printing. This is why you see layer lines with FDM printing whereas resin printing produces smoother prints. If it is aesthetics or the look of prints that you are after then resin printing should be your first choice.

The biggest downside to resin printers is they are not as easy to use. Resin printing requires a little more technical knowledge compared to FDM. 

FDM Printers

FDM printers are easier to use and therefore more beginner friendly. Also, if you are looking to print large parts or a large volume of prints, then FDM printers are the best choice. 

FDM printers are also more consistent in terms of how prints turn out. You are more likely to get varying results and inconsistencies when working with resin printers.

These qualities are the reasons why FDM is preferred for most 3D printing projects like prototyping for example. Also, FDM printing is a reversible process. A 3D print can be melted back into filament. Resin printing is a one way process. Once the resin has hardened it does not melt back into resin again.

What Are the Other Types of 3D Printing ?

There are up to seven types of 3D printing processes. FDM has a wide variety of materials that are reinforced with additives like metal and carbon to improve their strength. FDM is also more versatile compared to other types of 3D printing as it can be used in a wider variety of applications. 

There are other types of 3D printing technologies besides FDM and resin printing. These include:

  1. Selective Laser Sintering (SLS)
  2. Polyjet
  3. Direct Metal Laser Sintering (DMLS)
  4. Electron Beam Melting (EBM)
  5. Multi Jet Fusion (MJF)

On a side note, we recommend that you check out our post ” Can You 3D Print With A ( Glowforge ) Laser Printer? (Comparison)

sherifjallad

I am a very well experienced techie civil engineer who's extensively interested in 3D printing technology and even more captivated by the potential of 3D printing livable structures

Recent Posts