The additive manufacture and the BIEMH

What today already all the world knows like additive manufacture refers to a technology that began in United States 20 years ago and that at present is attaining his first successes. It treats of the fast manufacture of pieces splitting of digital data. It advances to a vertiginous rhythm that, after beginning like a formula of fast manufacture of prototypes, has become also a profitable alternative for the manufacture of tooling and, more recently, to an option with a high potential in the digital direct manufacture (pieces of final use, in short series). In the origin of his success are the limitations of the manufacture by means of conventional methods regarding the size of the batch to manufacture (For what manufacture in series if there is not demand for this?) And to the geometrical complexity of the component. But also it is necessary to take into account that now the society demands a manufacture medioambientalmente manager and sustainable.

Conceptually, the additive manufacture describes the technology in general and uses when it does reference to industrial applications of manufacture of components and with professional and industrial equipment of high provision. They exist other terms, being the most known ‘prototyping fast' or ‘impressesion 3D', in function of the scope of the model and the type of additive machine employee. In his favour play factors determinants. For example, the possibility to print a product in any part of the world from a simple computer archive, opens all a world of possibilities. Besides, it treats of a process that, in front of other traditional alternatives of manufacture, supposes big economic savings and of time. To all this it is necessary to add that they already have caducado the patents of two leaders of the market as they are Stratasys and 3D Systems, by what is producing a 'boom' world-wide of new agents that want to go in in this sector.

Layer on layer

Of form simplified, the manufactura additive consists in manipulating material to scale micrométrica and deposit it generally layer to layer, to create objects from data 3D of a model, of opposite form to the technicians of manufacture sustractiva. Inside this general field the processes can be of the most miscellaneous: laminación or LOM (employment of layers of different materials), fotolitografía or estereolitografía (use of light UV like basic process of solidification), fusion or selective sintering by laser (use of a do of laser and electrons for the consolidation of the material), polyjet (inject layers of fotopolímero liquid in a tray and cures to the instant by means of light UV) and modelling or deposition melted-FDM (deposition of thread melted layer to layer, of thermoplastic, ABS, like basic material).

On the other hand, the technicians of additive manufacture confer big competitive advantages because of his adaptation to the geometrical complexity and to the personalización of the design of the piece to manufacture. According to the sectors of application also can achieve: products lightened, products multimaterial, ergonomic products, short series of production, reduction of errors of setting and his costs associated, reduction of costs of investment in tooling, combination of distinct processes of manufacture, optimisation in the utilisation of material, manufacture more sustainable.

However, also presents inconvenient. For example, the superficial finishing in complex surfaces can have a rugosidad high. Besides, the time of manufacture is high, the materials have mechanical and thermal sensors properties limited that limit the behaviour in front of efforts and the tolerances are greater that in other methods of manufacture like the based in start of material.

Impressesion 3D

The impressesion by means of printers 3D, understands like one of the big industrial revolutions of the next years. They exist proposed to democratise the manufacture of units of distribution of low cost RepRap to the people of all the world through communities of users developers that exchange models 3D, knowledges and experiences to optimise the manufacture of a printer 3D autoreplicante.

As they explained in an article in the magazine Interempresas from the University Pontifica Comillas and of the Area of Engineering of the Design of UNED, the European Union has decided that the manufacture in general, and the additive in particular, was one of the key tools to tackle some of the European challenges and his back aims, especially for the growth and the creation of aggregated value of high quality of places of work. This decision is generating programs of support and promotion of the investigation and innovation to achieve that the additive manufacture allow to offer new products of high value, as well as competitive services.

Sectors customers

One of the sectors of big potential for these technical is the medical sector and odontológico and a good example is the development of ‘brackets' invisible, that come to substitute the ancient of metal, less aesthetic. It treats of a closely tied product to the design CAD, developed by means of a process that supposes a very tied automation to the net production of the product. The process of invisibility, besides, is applicable also to other fields of the medicine like the auditsory prostheses, where the traditional manufacture is being displaced by the technologies 3D, allowing customise the product to the form of each user. Also they exist products like staff planted, surgical implants and even the reconstruction of bone in cases of cancer (of jaw) or accidents of motorbike (reconstructions of skulls), substituting the metallic pieces used up to now.

The terms employed usually around the additive manufacture have gone evolving of parallel form to the development of the technology:

• ‘Rapid Prototyping'. Is the first term that used to describe the creation by means of layers of objects 3D. At present, the existent technologies, allow to achieve something more than a ‘prototype'.
• ‘Impressesion in 3D'. Is the most used term. It is frequent to employ the term of “Impressesion in 3D of low cost” when we employ machines of impressesion of domestic scope or semiprofesional.
• ‘Additive manufacture'. Is the last term applied and uses to describe the technology in general. It is very usual when it does reference to industrial applications of manufacture of components and with professional and industrial equipment of high provision.

The difference between these technicians reduces to the application that gives him to the technology of additive manufacture, that is to say, the difference between manufacturing an object with a functionality of comprobación ergonomic of the design and manufacture an element that serve of support to adjust two pieces in setting, is invalid when we speak of his manufacture, the nuance resides in the final function that will exert. Of this form, can use a technician of prototyping fast like possible technology of fast manufacture of elements, of tools or of moulds. The technical personnel, has to take into account that this possibility derives in a greater simplicity of the processes of setting and tuned of elements in his group.

A common characteristic to the different technical of additive manufacture is the one to require a minimum number of phases in the process of manufacture, from the development of the ‘idea' by part of the designer until the obtaining of the product finished. It is the own designer the one who can commission of the manufacture of the product. It is not necessary the intervention of another technician to realizar complementary operations. Nevertheless, it is necessary to take into account that during the process and before the manufacture, the designer has to know the conditionings of the final product, so much to know choose the ideal technician of manufacture, as to realizar the modifications of the file of geometrical data (stl) and review the code CN.

The processes of manufacture of conventional pieces are conditioned by a series of limitations related with the obtaining of some forms, like holes with path curve, angles of desmoldeo, control of the collisions of the tool with pieces of complex geometry, without forgetting that some processes of manufacture do not fulfil with a commitment with the sustainability in the manufacture and carry associated waste related with the utilisation of the liquids refrigerantes.

The technicians of additive manufacture distinguish mainly of the conventional technicians by two characteristics that, besides, confer them big competitive advantages while they do not put up the price of the process of manufacture: the geometrical complexity of the piece to manufacture and the personalización of the design of the piece to manufacture.

• The geometrical complexity of the piece to manufacture: can reproduce easily slim geometries, inner castings, internal channels, variable thicknesses, irregular forms, etc., and from a geometry obtained by a CAD 3D.
• The personalización of the design of the piece to manufacture: we Can obtain products exactly equal or entirely distinct without influencing notably in the process and without additional costs. This personalización is one of the main tendencies at present in the development of products of high value added, and his application in mass is one of the paradigms that pursues the industry in developed countries and that considers key for his sustainability.

These two characteristics can turn into big advantages in distinct industrial states:

• Products lightened. Can manufacture products designed for a determinate function and with conditions to measure, for example: lightened by reasons of weight, resistance and/or costs. Some of the technicians of additive manufacture can fill up a model with different degrees of porosidad on a same material.
• Products multimaterial. It is possible to manufacture a product contributing simultaneously several materials in a same solid; in this way, the technician surpasses one of the current limitations in the relation weigh/mechanical resistance, contributing new functionalities or abaratando costs of the product.
• Ergonomic products. The design of the components can reach a better interaction with the user adapting to the peculiarities antropométricas exact of each individual (prosthesis) without affecting necessarily to the costs of manufacture.
• Integrated mechanisms in a same piece. It is possible to manufacture a mechanism totally embebido in the piece in which it has to work, without need of settings and adjust back, for example: simultaneously an axis and his cojinete, a rolling, a dock and his support, a screw sinfín and his crown.

Advantages

From the point of view of the production of industrial components it is necessary to stand out as clear advantages:

• Reduction of the ‘time to market' of new designs.
• Short series of production.
• Reduction of errors of setting and his costs associated.
• Reduction of costs of investment in tooling.
• Hybrid processes: always it is possible to combine distinct processes of manufacture.
• Optimisation in the utilisation of material. The reduction of waste of material is minimum. The material generated like residue can recycle easily.
• Causes a more sustainable manufacture. They do not use directly toxic chemical products in an appreciable quantity.