The three basic 3D Printing technologies

When someone faces the challenge of buying a 3D printer, there are plenty of doubts that need an answer.

There is too much information available in the Net, and it makes difficult to surf so much data. We are going to try to simplify it for you.

In addition to this article reading, it is a good advice to look for local communities, if possible not for profit ones so you get unbiased information. In Barcelona, we are active members of the 3D Print Barcelona group, where talks and workshops of different 3D Printing themes are organized. There is a recurring talk “3D Printing Introduction” very useful to sort all the doubts that appear when entering this exciting world. Another star event is a workshop that shows the whole process from the idea in your mind until you end up with an object at your hands going through all the steps in between.

Piezas tres tecnologías base de impresión 3DAll 3D printers print with the same principle: they build the object layer by layer. If you think about a bottle, first layer will be a full disc as the bottom of the bottle, several layers up it will be printing a circle as the walls of the bottle, and at the neck there will be circles smaller and smaller as the neck gets narrower.
We will giving prices based on a customer base of prosumers, professionals and SMEs but for industrial 3D printers price may vary between 100k€ and 500k€ which we don’t mention here.

Let’s see the three 3D printing technologies.

FDM, also known as plastic or filament printers

FDM means Fused Deposition Modeling, because it melts material and spreads it. FDM is a Stratasys trademark but it is also the term used commonly.



They are the most commonly known, and they have taken the consumer market. Plastic melts through a hot nozzle and distributes it on the plane, to build a layer, then moves up and starts gain with the following layer. As it moves up building layers it creates the object.
Our Delta Black 3D printer is of this type of technology.


  • The cheapest machines: between €400 and €2500 depending if it is a kit or assembled.
  • The material is cheap: PLA is the most frequently used and costs between €15 and €20 a kg. A small model printing may use 15-20gr as a reference.
  • The cleanest. All materials can be touched with your own bare hands and there is not much rejected material. PLA doesn’t smell much. However ABS generates some harming vapors and it is better to print in a vented place.
  • They do not require post-processing. Worst case, if you have used supports to print the object you will have to take them out carefully.


  • Object stiffness. The layers blend together during printing by pushing material of the new layer on top of a layer, and they have small resistance to forces in the vertical direction as the object was printed.
  • You can notice layers. It is difficult to make a final product with this kind of 3D printing.
  • The layers shape is due to the nozzle pushing material over the last layer, and you can see and feel small layers shape.
  • Fails frequency. Melted material flow is subject to many factors that are difficult to control. Although this has improved a lot in the recent years, there are still more frequent fails than in the other technologies.


That’s the one used in consumer market. It Is used for everything.

At professional level it is used for prototyping, as long as you do not want to check mechanical properties.


SLS, or powder printer

SLS stands for Selective Laser Sintering, because it uses a laser to melt and blend the powder particles together. The most common material is polyamide, nylon is also used.



The printer has two boxes, one with the powder to be used for the printing and another where the object is built. There is a roll that spreads the powder homogeneously in a layer on the box here the object is created. The laser melts and blends the powder that belongs to the object in this layer. Then the bed goes down a bit and the roll replenishes another layer to start again.


  • Mechanical strength. It’s the only one that builds really solid objects. It is ideal for prototyping of mechanical parts, models, etc.
  • Low number of failures. It prints over material and the objects stand within the same powder.
  • No supports needed. The objects stand in the same powder and it is then ideal to make intricate objects.
  • Maximal production. Since the objects stand on the powder itself, you can print as many as you can fit in the volume, using not just the XY plane but also placing them vertically. A print run is optimized the most.


  • Printed objects are usually white; there is not a wide range of material colors as for FDM.
  • Price. It is generally for professional use, although the patent expired more than a year ago and we start to see low cost versions (low cost in this case meaning around 7000€ to 15000€). We are working in the prototype of a low cost SLS, by the way.
  • The finish is sort of grainy, not ideal for final product, although you can polish it and make it nice.
  • Post-processing. Although there is no need for supports, we have to take all the remaining powder out, quite dirty task if not done in a closed space.


Prototyping, architecture models. This is the rapid prototyping technology by itself, thanks to its mechanical propeerties.


SLA, DLP, or resin 3D printer

SLA stands for Stereolitography Apparatus, because it uses a laser ray to solidify the liquid resin.
DLP stands for Digital Light Processing, because it uses a DLP projector to send the image of the object layer that will solidify the resin.

Stereolithography apparatus SLA

SLA. Source:

SLA and DLP use similar material. A photosensitive resin hardens when it is exposed to UV rays. The only difference is how the UV is provided. SLA uses a laser ray that travels all over the object layer hardening point by point (voxels in fact). DLP projects a mask which is all the solid part of this object for this layer, and the rest is pitch black. Where there is light it hardens, where not it stays as is. Then the piece moves to let new liquid resin get in and apply the same process again with the next layer.


  • Detail. The detail level is unbeatable. That’s why it is used in jewelry and dental where detail is crucial.
  • Speed in DLP. As it projects a layer at a time, no matter how many objects you have, the printing speed is high compared to other methods.


  • Post-processing. It’s the most tedious. Resin always requires supports that you need to extract manually. In addition, you also have to clean the liquid resin remainders, and cure the object by exposing it to UV to finish solidification.
  • Material is dangerous. You need protection equipment to handle it. Best case scenario it’s no more dangerous than bleach, but some resin makers may be using cancer inducing substances.
  • Size. Printing size is usually small, since they are intended to small details pieces.
  • Price. There are several machines in the range of €2500-4000. Resin cost is around 80 €/L


Jewelry, dental and models. The fine details is the most appreciate characteristic of this technology, but as it is difficult and unpleasant to handle, only specific groups that really need details are using it.


There are many more technologies in the market, such as printing with layers of paper (Mcor), or directly with metal powder (DMLS). Check the wikipedia 3d printing entry for the full list.

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