156
N. Bogojevi´ c et al.
The key advantage of the AM technologies is their ability to build products with
complex shapes. The ability closes the gap between the theoretical models and experimental verifications for numerous research studies. For example, using a CAD and
FEA software package in conjunction with AM technologies, today it is relatively
easy to design and study lightweight parts, as well as parts optimized for specific
applications. While majority of the AM applications are based on the unique ability
of the technologies to build complex shapes, the applications are anyway affected by
the properties of the materials that are used to build the products. Since the material
properties are, in turn, affected by the production process of the AM technologies,
the current decade witnessed extensive studies of the properties of the AM materials.
Among many others, the fitness of the AM technologies for development of
various experimental setups attracted attention of those researchers who deal with
application of photoacoustic effect [1]. The ability of AM technologies to create
small structures with internal spaces could substantially increase sensitivity of the
photoacoustic measurement equipment. However, any application of the AM technologies for design of structures for control of sound propagation requires good
understanding of sound absorption and reflection properties of the structures [2].
Different researchers started to use AM to build specialized structures—metamaterials, which can be used to control the sound propagation, as demonstrated by
Jiang at all [3] and Liu [4]. In their research, the main focus was put on the geometrical characteristics of the structures produced by AM, and how these geometrical
characteristics can influence the coefficient of absorption of the structure. None of
the research, however, considered the influence of material to the sound absorption
during propagation through the structures.
AM comprises various technologies that differ in basic material and in principle of
joining the basic material to build the final product. While majority of AM technologies, such as stereolithography (SLA) and fused deposition modelling (FDM), require
specialized support structures to build the parts with overhanging features, the selective laser sintering (SLS) technology does not require these structures, which makes
the technology particularly suitable for building the parts with extremely complex
shapes and design. The important advantage of the SLS technology is based on use
of polyamide PA12 powder as the basic material and laser sintering as the principle
of joining the basic material. Due to such concept of the SLS technology, the nonsintered powder acts as the support to the product during building process. Further
advantage of the SLS technology is that the sintered PA12 has superior mechanical
properties in comparison with other polymer AM materials. Finally, the laser sintered
PA12 is stable against impact, chemicals, heat, UV light, water and dirt, and is also a
biocompatible material. Due to those advantages, the SLS technology is an optimal
choice for production of experimental equipment, and consequently, material properties of the laser sintered PA12 are subject of many studies [5]. This paper presents
a study of the coefficient of sound absorption of PA12 samples manufactured by
SLS technology, which is of interest for design of equipment used for studies of
sound propagation. To the best knowledge of the authors, the measurements of the
coefficient of sound absorption of laser sintered polyamide PA12 are not presented
in literature.
N. Bogojevi´ c et al.
The key advantage of the AM technologies is their ability to build products with
complex shapes. The ability closes the gap between the theoretical models and experimental verifications for numerous research studies. For example, using a CAD and
FEA software package in conjunction with AM technologies, today it is relatively
easy to design and study lightweight parts, as well as parts optimized for specific
applications. While majority of the AM applications are based on the unique ability
of the technologies to build complex shapes, the applications are anyway affected by
the properties of the materials that are used to build the products. Since the material
properties are, in turn, affected by the production process of the AM technologies,
the current decade witnessed extensive studies of the properties of the AM materials.
Among many others, the fitness of the AM technologies for development of
various experimental setups attracted attention of those researchers who deal with
application of photoacoustic effect [1]. The ability of AM technologies to create
small structures with internal spaces could substantially increase sensitivity of the
photoacoustic measurement equipment. However, any application of the AM technologies for design of structures for control of sound propagation requires good
understanding of sound absorption and reflection properties of the structures [2].
Different researchers started to use AM to build specialized structures—metamaterials, which can be used to control the sound propagation, as demonstrated by
Jiang at all [3] and Liu [4]. In their research, the main focus was put on the geometrical characteristics of the structures produced by AM, and how these geometrical
characteristics can influence the coefficient of absorption of the structure. None of
the research, however, considered the influence of material to the sound absorption
during propagation through the structures.
AM comprises various technologies that differ in basic material and in principle of
joining the basic material to build the final product. While majority of AM technologies, such as stereolithography (SLA) and fused deposition modelling (FDM), require
specialized support structures to build the parts with overhanging features, the selective laser sintering (SLS) technology does not require these structures, which makes
the technology particularly suitable for building the parts with extremely complex
shapes and design. The important advantage of the SLS technology is based on use
of polyamide PA12 powder as the basic material and laser sintering as the principle
of joining the basic material. Due to such concept of the SLS technology, the nonsintered powder acts as the support to the product during building process. Further
advantage of the SLS technology is that the sintered PA12 has superior mechanical
properties in comparison with other polymer AM materials. Finally, the laser sintered
PA12 is stable against impact, chemicals, heat, UV light, water and dirt, and is also a
biocompatible material. Due to those advantages, the SLS technology is an optimal
choice for production of experimental equipment, and consequently, material properties of the laser sintered PA12 are subject of many studies [5]. This paper presents
a study of the coefficient of sound absorption of PA12 samples manufactured by
SLS technology, which is of interest for design of equipment used for studies of
sound propagation. To the best knowledge of the authors, the measurements of the
coefficient of sound absorption of laser sintered polyamide PA12 are not presented
in literature.