Rapid prototyping on a 3D printer

Layer-by-layer welding (FDM) 

This technology involves the creation of 3D parts in layers, with each layer involves heating the consumable material, which is extruded through a nozzle with a hole of a certain diameter. Plastics are used for printing, but metal and even chocolate are possible. This method of prototyping is characterized by low speed, relatively low resolution, problems with fixing elements on the working surface. On the other hand, FDM is popular due to the low cost of filament, which is a significant advantage for FDM 3D printing. The most commonly used filament types are PLA (Polylactic acid), ABS (Acrylonitrile butadiene styrene), and PETG (Polyethylene terephthalate) which each has their own advantages and disadvantages. There's a lot of other types of plastics used as well, like different types of flexibles, PEEK, Nylon and so on. 

The positive

• Cheap printers
• Low cost of consumables

The negative

• Low printing speed
• Relatively low resolution

Stereolithography (SLA)

This technology involves the use of liquid photopolymer, which adds a special reagent. This mixture is subjected to polymerization under the influence of ultraviolet laser. The construction of the layers is performed sequentially, while not without the use of a movable substrate with holes. The peculiarity of the technology is its complexity: firstly, it is required to properly prepare a photopolymer, secondly, complete polymerization takes a lot of time. 

The positive

• High print resolution and high accuracy.
• Ability to print large-sized models.
• The mechanical strength of each model.
• The minimum amount of waste.

The negative

• The limited choice of materials
• Low print speed
• The inability to create color parts.

Selective Laser Sintering (SLS)

3D prototyping based on this technology assumes that the part is created in layers based on powder. First, the material is evenly distributed in the horizontal plane, after which the individual sections are sintered by a laser beam. As a starting material, it is advisable to use metal, plastic, ceramics, glass or casting wax. The powder is applied to the surface of the desktop with a special roller. The powder is preheated to reduce the power of the laser that will sinter parts of the part. Most of the three-dimensional models obtained by the SLS technology require finishing, for example, polishing. Settings for printing with this method make it possible to create large objects. SLS technology options are selective laser sintering (SLM) and electron beam melting (EBM).

The positive

• The ability to use a wide range of materials.
• Creating complex three-dimensional parts.
• High speed and print quality.
• The possibility of creating not only prototypes but also small-scale production.

The negative

• The need for a powerful laser
• An airtight chamber
• A low maximum resolution
• Preparatory work on heating the powder.

• Multiple-jet modeling (JMM)

 Printers for this technology are created by 3D Systems. Rapid prototyping is carried out on the principle of conventional inkjet printing: the material is fed through nozzles of small diameter, which are located directly on the printhead. The consumable material is first heated to the melting temperature, then fed to the extruder, after which it is layered applied and subsequently cured. The formation of layers is performed horizontally, then vertically shifts when moving to the next layer. JMM printers work on the basis of various types of plastics, photopolymers, and special wax. It is also possible to combine materials. When using photopolymers will require hardening of the parts - for this it is exposed to ultraviolet light. 

The positive

• A small thickness of the layer of detail and the resolution of the construction of the surface.
• Multi-color printing and the possibility of combining materials.
• Compact printers.

Lamination (LOM)

The method of layer-by-layer bonding of films involves cutting thin sheets of material with a laser beam or a special blade, after which the parts are interconnected. 3D models can be created from various materials - from plastic to ceramics and metal. For example, a Mcor IRIS color printer prints based on A4 paper, which is colored in a specific color. After printing, the finished sheets are entered into a 3D printer, where they are cut on the borders of a particular image. Then the obtained elements are glued together. The third stage is the disposal of waste, which in this technology a lot. 

The positive

• Full-color printing with high resolution.
• The availability of the main consumables paper.
• The ability to create large models.
• Lack of need for supporting support if the difficult three-dimensional part is created.

The negative

• Limited choice of materials
• The dependence of the layer thickness on the thickness of consumables used
• Large amount of waste
• The need for finishing parts.