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Remanufacturing and Advanced Machining
that AM could contribute to in order to extend the product life span. This cost-effective approach has been usefully exploited for metal parts offering a great potential
for repair of damaged components. Likewise, reverse engineering is an approach to
foster repairing and refurbishing. Finally, concerning the recycling process, several
initiatives have been reported to create low-cost extruders to produce plastic filament
for FFF devices. Recycled filaments and some organizations recycling waste plastic
toward products with a higher added value can be mentioned as important recent
trends (Sanchez et al., 2020).
Le et al. (2017) performed a review of AM techniques in repairing and remanufacturing. They provide examples of laser cladding used for building of new
Ti-6Al-4V entities on old Ti-6Al-4V substrates and of directed energy deposition
(DED) technologies especially suitable for repairing and remanufacturing as well as
adding new functionalities to existing parts. Due to the flexible material deposition
configuration of a five-axis CNC machine, these techniques have been successfully
applied to remanufacturing of worn-out or damaged components, particularly for
high-value components, such as turbine blades, molds, and dies, restoring them to
original specifications and qualities.
The authors point out that powder bed fusion (PBF) techniques, such as electron beam melting and selective laser melting, have some limitations in repairing
and remanufacturing abilities, compared with DED, due to their limited build envelope and deposition of materials on horizontal flat surfaces only. However, there are
numerous components which can be repaired or remanufactured by these processes,
e.g., gas turbine burner tips. EBM technology enabled building a copper entity on
top of an existing Ti-6Al-4V part with a good metallurgical bonding at the interface between the two materials. It was found that EBM not only has the potential
to produce multi-material parts, e.g., joining Inconel 718 with 316L Stainless Steel,
but also to be used for remanufacturing applications and building new features on
existing parts. The existence of strong bonding between EBM-built entities and the
existing part was demonstrated by microstructure observation and tensile testing. In
a similar way, multi-material parts can be built by SLM ensuring a good bonding
at the interface between two materials, while new features can be built on existing
components. This way it is possible to obtain new parts by adding new entities to
the existing components. The parts obtained have a good “material health”, which
means that their mechanical characteristics are compatible with industrial applications (Le et al., 2017).
Pfähler et al. (2019) present results of a survey of AM’s application possibilities
considering product life cycle. They mention rapid prototyping, rapid tooling, rapid
manufacturing, and efficient product as well-established applications of AM within
the manufacturing industry. In particular, rapid prototyping is used for rapid production of prototypes, where AM is most likely to be used for fast production of small
batches on demand reducing the time to market. Rapid manufacturing describes
usage of AM for large series and small series production which is achieved through
the increasing diversity of materials available in AM.
Rapid tooling describes manufacture of tools and appliances for production. When
a small quantity of components is required and production of a required tool is not
Remanufacturing and Advanced Machining
that AM could contribute to in order to extend the product life span. This cost-effective approach has been usefully exploited for metal parts offering a great potential
for repair of damaged components. Likewise, reverse engineering is an approach to
foster repairing and refurbishing. Finally, concerning the recycling process, several
initiatives have been reported to create low-cost extruders to produce plastic filament
for FFF devices. Recycled filaments and some organizations recycling waste plastic
toward products with a higher added value can be mentioned as important recent
trends (Sanchez et al., 2020).
Le et al. (2017) performed a review of AM techniques in repairing and remanufacturing. They provide examples of laser cladding used for building of new
Ti-6Al-4V entities on old Ti-6Al-4V substrates and of directed energy deposition
(DED) technologies especially suitable for repairing and remanufacturing as well as
adding new functionalities to existing parts. Due to the flexible material deposition
configuration of a five-axis CNC machine, these techniques have been successfully
applied to remanufacturing of worn-out or damaged components, particularly for
high-value components, such as turbine blades, molds, and dies, restoring them to
original specifications and qualities.
The authors point out that powder bed fusion (PBF) techniques, such as electron beam melting and selective laser melting, have some limitations in repairing
and remanufacturing abilities, compared with DED, due to their limited build envelope and deposition of materials on horizontal flat surfaces only. However, there are
numerous components which can be repaired or remanufactured by these processes,
e.g., gas turbine burner tips. EBM technology enabled building a copper entity on
top of an existing Ti-6Al-4V part with a good metallurgical bonding at the interface between the two materials. It was found that EBM not only has the potential
to produce multi-material parts, e.g., joining Inconel 718 with 316L Stainless Steel,
but also to be used for remanufacturing applications and building new features on
existing parts. The existence of strong bonding between EBM-built entities and the
existing part was demonstrated by microstructure observation and tensile testing. In
a similar way, multi-material parts can be built by SLM ensuring a good bonding
at the interface between two materials, while new features can be built on existing
components. This way it is possible to obtain new parts by adding new entities to
the existing components. The parts obtained have a good “material health”, which
means that their mechanical characteristics are compatible with industrial applications (Le et al., 2017).
Pfähler et al. (2019) present results of a survey of AM’s application possibilities
considering product life cycle. They mention rapid prototyping, rapid tooling, rapid
manufacturing, and efficient product as well-established applications of AM within
the manufacturing industry. In particular, rapid prototyping is used for rapid production of prototypes, where AM is most likely to be used for fast production of small
batches on demand reducing the time to market. Rapid manufacturing describes
usage of AM for large series and small series production which is achieved through
the increasing diversity of materials available in AM.
Rapid tooling describes manufacture of tools and appliances for production. When
a small quantity of components is required and production of a required tool is not