Potential hazards are the key criterion for occupational safety assessments. In additive manufacturing however, the catalogues of criteria for occupational safety and health are still far from adequate. No clear picture of the situation has therefore emerged as yet. Relevant guidelines could help to ensure the protection of workers and make production both safe and efficient.
Additive manufacturing (also termed 3D printing) has become increasingly important to industry in recent years. The concept of manufacturing components by applying material in layers may appear new; however, additive processes were already known and in use in the early nineteen-fifties. Since then, the number of available processes has increased hugely, accompanied by a rapid increase in the range of materials used. The processes along the additive process chain differ in their hazard potentials.
Harmless – or not?
Common to all processes is that a feedstock is compiled to form a component. The processes by which this occurs differ according to the material and may take the form of a bonding, melting or physical-chemical process. The materials used differ in the level of hazard they present. They may for example be respirable or explosive powders, or they may release substances during the joining process that are potentially harmful to health. Potential hazards are also presented by laser beams, and by sources of heat such as fusion nozzles or ovens for thermal post-processing.
Occupational safety must also be taken into account during the handling of material and post-processing of 3D-printed parts. Almost all parts manufactured additively require some form of post-processing. Separating the part from the build platform, removing residual material or support structures and finishing the surface are all steps that require either mechanical working or the use of auxiliary chemical materials. Potential for injury is presented by parts that have not cooled sufficiently, needle-like support geometries, powders (possibly respirable) and harmful vapours.
VDI guidelines already exist for some processes. They provide a carefully prepared introductory approach to identifying the primary potential hazards and taking suitable measures to ensure that processes are safe. "Additive manufacturing in particular requires a modern approach to defining protective measures. The measures needed are defined with reference to the state of the art. This in turn is described by relevant codes and rules. Rules for industrial safety, the handling of materials and occupational safety interact and serve as a yardstick for an appropriate risk assessment," says Martin Worbis, engineer and labour inspector for the southern prevention region at the German Social Accident Insurance Institution for the woodworking and metalworking industries.
Participation is called for
Industry experts are called upon to contribute to the development of relevant standards and codes in order to cover the various aspects with respect to occupational safety and standardization, and also to take account of the needs of industry and the affected persons. Professor Dr Christian Seidel of Munich University of Applied Sciences and Chairman of ISO Committee TC 261, Additive Manufacturing, comments: "Occupational safety is an important topic in additive manufacturing. Concepts have been implemented in the field which often appear over-ambitious or conversely do not go far enough. The great challenge is to find the right, adequate measure. For this reason, much has already been done on the VDI's committees and to some extent also within ISO to provide users of the technology with comprehensible, process-specific codes for dealing with this topic appropriately. A highly comprehensive document is available in the form of VDI 3405 Parts 6.1 to 6.3. If timely consideration is given to the measures needed, the protection required for employees can be put in place without impairing flexibility and efficiency." Summing up the need for cooperation, Corrado Mattiuzzo, Head of the Technical and Scientific Department at the KAN Secretariat, points out that "there is already a great deal of interest in standardizing additive manufacturing processes. However, the national and international standards committees are dominated by installation and component manufacturers, test bodies and users. We therefore urgently appeal to OSH experts to join in playing an active part in standardization, to ensure that future standards meet the expectations of those involved in prevention and are compatible with the national OSH regulatory framework."
Conclusion: Occupational safety and health in additive manufacturing is an issue in which industry and the responsible bodies have a responsibility to provide practicable and appropriate guidance and codes to enable safe and, as far as possible, hazard-free work and research, without presenting an obstacle to innovation. This is an exciting field that can learn and benefit from the expertise of conventional manufacturing, but must nevertheless find solutions of its own that address the particular aspects of the subject.
Freelance author and
editor-in-chief of the
Additive Fertigung journal published by x-technik