Study of the Environmental Implications of Using Metal Powder in Additive Manufacturing and Its Handling

Abstract

Additive Manufacturing, AM, is considered to be environmentally friendly when compared to conventional manufacturing processes. Most researchers focus on resource consumption when performing the corresponding Life Cycle Analysis, LCA, of AM. To that end, the sustainability of AM is compared to processes like milling. Nevertheless, factors such as resource use, pollution, and the effects of AM on human health and society should be also taken into account before determining its environmental impact. In addition, in powder-based AM, handling the powder becomes an issue to be addressed, considering both the operator´s health and the subsequent management of the powder used. In view of these requirements, the fundamentals of the different powder-based AM processes were studied and special attention paid to the health risks derived from the high concentrations of certain chemical compounds existing in the typically employed materials. A review of previous work related to the environmental impact of AM is presented, highlighting the gaps found and the areas where deeper research is required. Finally, the implications of the reuse of metallic powder and the procedures to be followed for the disposal of waste are studied.2 of 25 sold in 2016 was 983, whereas, in the year 2017 this value rose to 1768 units, which implies an 80% increase [1].As far as economy and sustainability are concerned, AM offers several advantages over conventional manufacturing techniques, which confers many potential applications to AM in diverse industrial sectors, such as automotive, aerospace, biomedical, energy, and consumer goods [4]. In the aerospace industry, for example, AM enables aerospace motorists to create blades with much more complex internal cooling channels, allowing engines to run at higher temperatures and thus increase their performance [5]. In the report presented by the National Institute of Standards and Technology (NIST) of the U.S. Department of Commerce, it is stated that in aerospace engines titanium parts are machined down to size from large initial blocks, which leads to more than 90% waste material, material waste that could be reduced by using AM [6]. The European Commission in the Digital Transformation Monitor of 2017 presented similar numbers, where the disruptive nature of 3D printing was studied. It was estimated that by 2050, AM could save up to 90% of the raw material needed for manufacturing [3].Nonetheless, the possibilities of AM are not only limited to a reduction of raw material usage. The possibility of manufacturing lighter components could lead to energy savings, estimated between 5% and 25% by 2050, as well as a reduction in manufacturing costs of around 4-21% for the same period [7]. This trend is applicable to different industrial sectors. For example, SmarTech expects the overall market for AM in automotive to reach 5.3 billion USD in revenues by 2023 and to achieve 12.4 billion USD by 2028 [8].The lack of European and international standardization related to AM is proving to be an impediment to the...

Functionally Graded AISI 316L and AISI H13 Manufactured by L-DED for Die and Mould Applications

“…Additive manufacturing (AM) technologies have emerged as an alternative to traditional manufacturing processes to produce complex, fully dense, and functional parts [1]. Additive processes were originally conceived as a tool to provide a quick representation of components, that is, rapid prototyping.…”

“…The rapid solidification of the molten metal inherent to this process allows unique microstructures and phases to be formed, unachievable by equilibrium cooling [6]. As far as the application field of L-DED is concerned, and although it is capable of manufacturing fully functional end-parts, nowadays it is mostly employed for the remanufacture, repair, and coating of high-added-value parts in the aerospace or the die and mould industry [1]. In fact, the highly localised energy input of the laser provides a strong metallurgical bond between the added material and the substrate, while the base material retains its mechanical properties unimpaired due to the reduced heat-affected zone [7].…”

Nanoparticle Exposure and Workplace Measurements During Processes Related to 3D Printing of a Metal Object

“…Solid based AM covers fused deposition, where heat is used to melt solid plastics or polymers and fuse it to subsequent layers. Powder-based AM covers metal and ceramics 3D printing, where Laser Powder Bed Fusion (L-PBF), which is the process used in selective laser melting (SLM) and direct metal laser sintering (DMLS), is the most used method (5). Here feedstock powders fusing in layers by selective illumination with a laser by either melting the powder completely for SLM or partially melting it and then sintering it in the case of DMLS.…”

Applications of Additively Manufactured Tools in Abrasive Machining—A Literature Review

“…Additional surface treatment can be conducted to improve the surface finish. This also includes cleaning the internal channels or removing the partially melted particles on the part [ 70 ]. During the final stage, inspection on the basis of contact or non-contact measurements, as well as non-destructive testing (NDT) [ 71 ], is usually conducted.…”