Additive manufacturing is playing an increasingly important role in industry and automation technology. The article describes the most important processes, functionalities and applications.
Additive manufacturing – also commonly known as 3D printing – is an innovative manufacturing process that is fundamentally different from conventional manufacturing processes and offers the industry completely new possibilities.
Unlike previously known manufacturing processes, components in additive manufacturing are built up layer by layer and are not created by removing material – as is the case with milling, for example. The process is therefore based on digital 3D designs and the component is created by depositing additive manufacturing materials such as metals, plastics and composites. As a result, the process offers a great deal of flexibility and design freedom – both in the production of prototypes and in series production.
Additive manufacturing is used for rapid prototyping, i.e. the production of visual and functional prototypes, rapid manufacturing, i.e. the production of end products, and rapid tooling, i.e. the production of tools and molds.
In the industrial sector in particular, there are a wide variety of processes and applications, some of which are very different, for which the additive manufacturing process is very well suited. Additive manufacturing also includes methods that have little to do with 3D printing. Laser melting, for example, is not based on step-by-step material buildup, but on the slow fusion of powders. And the areas of application also differ: Rapid prototyping, for example, is about producing models quickly, usually without high requirements. Rapid tooling, on the other hand, is used to produce highly specialized tools that have to withstand extreme mechanical requirements.
Additive manufacturing and subtractive processes are two fundamentally different approaches to manufacturing a workpiece. In the subtractive method, for example, the component is produced by ablation, i.e. by removing material. This manufacturing method is also called "machining".
In additive manufacturing, on the other hand, material is applied layer by layer according to the so-called layer construction principle. With this method, there are hardly any design restrictions and extremely complex structures can be implemented. A special effect of the layered construction is the "stair-step effects". These manifest themselves in small distances between the individual layers and are typical of many additive processes. The effect can be reduced by a lower layer thickness, but not completely avoided.
The most commonly used additive manufacturing processes are polymer or plastic printing and metal printing. Within both printing processes, there are numerous specialized additive processes. In addition, there are manufacturing processes that combine the advantages of additive and subtractive techniques. These are referred to as hybrid processes.
Other important 3D printing processes are as follows:
Additive manufacturing, or 3D printing, got its start in the 1980s. While the concept of 3D printing emerged in the 1970s, the first practical trials can be traced back to 1981. The first 3D design program was launched in 1985, and the inventors filed their first patent application the following year. The first 3D printer was available for purchase in 1988.
Also in 1988, fused layer modeling was invented, and the first modeling system was launched three years later. Following the introduction of various technologists, fused layer modeling printers have been available for private users since 2010. In parallel, 3D screen printing developed from screen printing, which had been used for a long time.
In some areas, additive manufacturing has already been used profitably for some time:
Rapid Prototyping: The term refers to the fast, uncomplicated production of prototypes and the additive techniques that can be used to quickly and cheaply produce a three-dimensional model of a component. It is one of the most mature applications in the field of additive manufacturing.
Rapid tooling: This term refers to the manufacture of machine or production tools using additive manufacturing. Since this type of tooling is usually less complex and time-consuming as well as less expensive, manufacturers like to use additively manufactured tools. Other advantages include great design freedom, function integration and fast manufacturing processes. Production times and process chains can be shortened or accelerated, and less material is used.
Rapid and direct manufacturing: These are processes used to produce additive products directly from CAD data. The focus of both applications is on the fast implementation of the components. Since no tools or other aids are required, rapid and direct manufacturing are often much faster than other processes. The use of both processes makes sense if you want to produce a part in a small run and/or it has a special geometry that would be difficult or impossible to realize using other methods. This is the case, for example, in the production of industrial spare parts.
Rapid Repair: This process refers to the repair of broken tools or other objects. The worn tool then does not have to be disposed of immediately, but can be quickly rebuilt using additive manufacturing.
Design freedom: With the help of additive manufacturing, an almost infinite number of complex shapes can be produced. Many of the limitations of traditional manufacturing processes are eliminated. In prototyping, costs can often be significantly reduced with 3D-printed models.
Individualization: With additive manufacturing, standardized products are a thing of the past. Individual solutions for components or tools can be realized and the respective needs and requirements are the focus of the process. For example, there are now additively manufactured heart valves that can be optimally adapted to the patient’s personal requirements.
Speed: Many process steps of classic manufacturing methods, which used to take days or weeks, are no longer needed thanks to additive manufacturing. In addition, corrections at short notice are no problem.
Cost savings: As a rule, manufacturing costs are noticeably reduced with additive manufacturing. The reason is faster production, shortened process chains and low material consumption.
The disadvantages of additive manufacturing lie primarily in the post-processing of the manufactured parts. Components produced by additive manufacturing require extensive post-processing in order to obtain the desired surface.
In addition, additively manufactured parts are good for small series, but are only suitable for mass production to a limited extent (no customization options). Compared to conventional processes, they still take too long to produce parts. As a manufacturing method, they are therefore rather uneconomical for mass production. One example is vehicle manufacturing: theoretically, it would be possible to produce a complete vehicle using additive manufacturing. However, due to the many components involved, this would be far too costly.
A lack of know-how in companies is also a problem. Around half of all companies state that a lack of knowledge in design and implementation prevents them from introducing additive processes. One reason for this is that skilled workers are predominantly concerned with conventional manufacturing methods during their training and less with additive manufacturing.
Often, the high investment and operating costs also cause plans to introduce additive processes to fail. For example, the majority of companies that do not use additive processes say they shy away from the costs associated with it. In fact, the acquisition costs for the machines and other material are quite high.
The terms additive manufacturing and 3D printing are increasingly used as synonyms. Additive manufacturing is a professional manufacturing process that has some differences from conventional production processes. For example, in additive manufacturing, components are built up layer by layer (layer construction principle), whereas in conventional processes material is removed.
The advantages of additive manufacturing lie in its speed and freedom of design, the customization options and the associated cost savings. However, companies are often deterred from introducing additive processes because the initial costs seem too high or because their employees do not have sufficient expertise in additive manufacturing. In addition, components created by additive manufacturing usually still have to be reworked.
Due to its many advantages, additive manufacturing holds enormous potential for many industries. It can not only optimally complement conventional processes, but could even completely replace them in the future.
