How to 3D print: techniques in comparison

3D printing over the years has been used by several companies to develop prototypes or high-engineered parts to be used for different production purposes.

The reduced costs of 3D printing have allowed it to be accessible to many companies and used in various market sectors. 

Since 3D printing must be able to respond to different applications and uses, over the years different techniques have been created, developed specifically to be able to use certain materials, reproduce large objects, etc. 

Among the various models on the market today, you can choose the most suitable machine based on materials, technical characteristics and costs, of course.

In this article we will consider 3D printers for industrial use that use plastic materials. We will explain the different technologies and capabilities. 

Fused deposition modelling (FDM)

The FDM (fused deposition modeling) 3D printing technique is one of the most widespread commercially, especially thanks to the hobbyist market.

This technology melts and extrudes a thermoplastic filament, which is deposited through a printing nozzle that moves along the printing table, building the desired object layer by layer. 

The characteristics of the fused deposition technique are:

• The ability to melt and extrude the plastic filament;

• The lowest price for initial investment also considering the materials;

• Lower resolution and accuracy, compared to other 3D machines;

• They are usually used for the prototyping of simple objects.

Melt deposition modeling uses different plastics (ABS, PLA and various mixtures), materials suitable for rapid prototyping. Although its precision is not among the best, this process allows you to obtain simple models and parts of them at low cost and in a short time. 

Therefore, it is important to bear in mind that in this case, resolution and precision are omitted in favour of simple timescales and processes, which can subsequently be perfected through other post-production processes such as mechanical or chemical polishing. 

Stereolithography (SLA)

3D printing with SLA technique was invented during the 1980s and represents the first 3D printing technique in the world. Despite its age, it is still among the most used 3D printing technologies at a professional level. 

This machine works by means of a laser that cures the liquid resin and makes it hard plastic, through the photopolymerization process.

The main features of stereolithography:

• It uses the laser to cure the photopolymer resin;

• It can be used to process a wide range of materials;

• It offers a good resolution, especially for projects that contain details and particulars;

• The main use is functional prototyping, modeling, moulding, and equipment.

The advantages of this technique are in the resolution and precision of the project to be developed. In fact, SLA 3D printing is able to reproduce complex objects and is very versatile, thanks to the wide range of materials available. In fact, it is possible to propose different optical, mechanical and thermal properties and very similar to industrial thermoplastics. 

So, if you have a project in hand that requires complex modelling and is full of details, SLA 3D printing is the right choice for the creation of your prototype.

Sintering laser selective (SLS)

SLS 3D printers melt polymer powder particles using a high-powered laser.

Unlike FDM 3D printing, the SLS does not need support thanks to the powder that is left in surplus and serves as a basis for processing.

The main features of SLS machine:

• It uses the laser to melt the polymer powder;

• It has limited costs and high productivity, thanks to the fact that there is no need for a support structure;

• The mechanical properties are excellent and allow results very similar to traditional injection moulding techniques;

• The main use for which it is used are functional prototypes and the production of parts for end use.

SLS 3D printing is excellent for creating complex geometries, angles, and details, even in negative. In addition, its resolution is excellent and allows you to reproduce mechanical parts with characteristics similar to the injection technique.

Nylon is one of the most used materials for this printer. The characteristics of this material are: lightness, strength, and flexibility, which allow nylon to guarantee high performance even in the case of processes that involve the use of chemical substances, UV rays or other.

Therefore, the SLS 3D printer is excellent for the realization of projects with complex shapes and geometries, for objects that require strength and flexibility and above all for low costs thanks to a limited number of parts that require maintenance.

Conclusions

It is important to understand the characteristics of your project and consciously decide on the type of 3D printing that best suits the creation of your object. 

To do this, it is necessary to be clear about the objectives of the creation you want to achieve: before proceeding with printing, it is important to carefully evaluate the complexity of the shapes, the resolution you want to achieve and the characteristics of the materials you intend to use. All these evaluations will help you achieve maximum achievement depending on the purpose of end use of your item.