3D Printing

FDM (Fused Deposition Modelling) falls under the material extrusion category of 3D printing technology. This technology was invented and patented by Scott Crump, co-founder of Stratasys, in 1989. An FDM printer uses a thermoplastic polymer in a filament form to create three-dimensional objects. 

In an FDM printer, the filament is pushed into the hot extruder. The filament is heated first and then deposited, through the nozzle, onto a build platform in a layer-by-layer process to form the complete object. 

Resin printing, Vat Photopolymerization category of 3D printing technology. This was the world’s first ever patented 3D printing technology and was invented by Charles Hull, an American engineer, in the mid-1980s.

This method uses a liquid resin material to print objects. This technology uses a powerful laser or more common LCD to form the 3D object. In this technology a light source sits at the bottom of the vat filled with liquid thermosetting resin. The laser is selectively flashed onto the liquid photosensitive resin and the exposure to the light cures (hardens) the material. This process is followed until every single point on the layer is exposed and hardened. Once completed, the process moves towards the next layer and then to the next. This process continues until the entire model is cured and the resulting 3D print is ready. 

FDM: FDM printers use a wide range of thermoplastic polymers, but also composites in the form of a filament. Since the base thermoplastic materials are cheap, the filaments as well are quite affordable and can be found at comparable prices across the world. One kilogram of 3D printing filament can range from £24 to £99, depending on the material type and quality.

Resin: Resin printers have a more limited range of materials available for 3D printing. Resin uses photosensitive thermosetting plastics in a liquid resin form. The resins are costly and are mostly manufactured by Resin printer manufacturers. One litre of resin costs approximately £50 to £150, depending on type and quality.

These are highly specialized materials used for specific applications like dental, jewellery, tough, high-temperature, etc.

FDM: FDM’s material availability is matched by its colour selection. Regardless of material type, dyes can easily be combined with the material in production to produce a full palette of colours giving designers and engineers lots of flexibility. With a wide range of materials suppliers comes even more variety in colours, with some manufacturers even offering custom colour matching for selective customers.

Resin: Resin materials do not offer a large variety of colours and are generally found in black, grey and transparent colours. All the  Resin materials however are blended forms of the original base material and so they are available as application-based materials. While colours are often limited, there are certain instances in which experimenters can mix in their own pigments to create various colours, though this can be a difficult process.

FDM: The surface finish achieved through FDM printers is coarse and the layer lines are clearly visible due to the minimum layer height. The line thickness as seen from above is typically around 400 microns (the bead resulting from the diameter of the nozzle). The line thickness as seen from the side can be adjusted typically from 50 - 400 microns - this is called resolution or layer height.

 Resin: Because Resin printers utilize a light for “drawing” each line of the part, the resulting lines can be much smaller and more precise resulting in a smooth surface finish. The approximate width of the light and the resulting cured lines is 20 microns.

FDM: FDM 3D printing achieves good dimensional accuracy for larger features. For smaller features, the dimensional accuracy is hampered and sometimes is not consistent. This can also be hampered depending on the 3D printer type (DIY, desktop, professional, or industrial FDM printer). Choosing the right 3D printer becomes a task because the accuracy also depends on other factors like the calibration and slicer settings. Materials also play a role in the accuracy through their shrinkage properties.

Resin: As a Resin printer is able to achieve a very fine resolution, the dimensional accuracy is unmatched by most of the other 3D printing technologies. If the primary objective is surface finish and accuracy on fine features (such as in jewellery or dentistry), Resin is a great choice.

FDM: FDM printers tend to have an advantage when it comes to producing durable, usable, long-lasting parts due to their ability to print in known polymers and composites. Printing in nylon carbon fibre, for example, will allow for a lightweight part that is incredibly strong.

Resin: Typically, Resin printers are known more for their creation of delicate and detailed parts rather than for strong parts. This is due to a combination of factors. For one, cured resins tend to be fairly brittle. Another reason is that unlike FDM prints, Resin prints cannot be printed solid as such parts will result in cracks, warping, and often print failure. There have been some new stronger resins in development, but they are far from perfect and have often not been proven in the field as have many of the known polymers and composites on the FDM side.

FDM: FDM printers are fairly straightforward - insert plastic filament in one end, and extruder out the other. This simplicity and relative cleanliness has made FDM printers a choice for those who want to use them in an open office or educational environment. The parts come out dry and clean, and often there is just the singular post-processing of removing supports by breaking them off. The remaining material is easily stored in hard plastic filament form for the next print.

Resin: While Resin printed parts can be nice looking, there is a little extra work that goes into the process. The nature of printing parts in a liquid resin can be too much of a hassle for some due to the resulting mess - parts come out sticky, and resin can find its way into the larger workspace. Also the resin can be highly toxic - requiring the use of goggles, gloves, and other protective equipment. 

Post-processing involves multiple steps - first washing the print to remove excess resin, followed by clipping off supports which requires clippers. Lastly, a further curing process using a UV lamp is recommended to finish the part. The remaining material of liquid resin must be kept in the tray away from light and has a short shelf life once in the tray.

FDM: FDM is the most affordable technology available in the entire space. It is not only inexpensive in terms of the actual machine but also in its operations as the materials are comparatively less expensive than those for other technologies. As a result, products manufactured through FDM 3D printing tend to be less expensive than for comparative products.

Resin: The Resin printer is a costly machine. It involves the use of expensive parts like laser or LCD screen and scanning mirrors. The materials are also expensive. Additionally, almost all the models require some amount of support structures and so 3D printed output also gets expensive. 

FDM printers and Resin printers have proven popular across many industries and their use continues to grow. While some may choose one technology over the other, many see the benefit of utilizing both alongside each other and benefiting from each technology’s strength. For example, a designer at a company might choose to use Resin to get a detailed look at a final part, while an engineer might use FDM to produce a part in a production material, such as ABS, for prototype testing. 

If you have to choose one or the other - ask yourself if you need a more robust part printed in more common materials, or if you need a highly detailed part that looks nice. If you need a stronger, usable part, FDM might be the way to go, but if you just need a nice looking, detailed part, then Resin might be your choice. Either way, 3D printing is a great way to quickly take a digital design and make it a physical reality!

With this information hopefully it helps you choose the right option for you. Please note final price is calculated on weight of the object before clean up and must be considered while choosing the material and size. Call M. A. CAD Services today on 07513275255 or use the contact page to discuss your requirements.