78
Remanufacturing and Advanced Machining
approaches show sufficient load-bearing capabilities for automotive applications. All
of these methods have individual advantages and disadvantages, and a decision to
apply one or more technologies in a particular production depends on requirements
like production volume, required strength, material flexibility, costs, etc. (Meschut
et al., 2014).
Advancing miniaturization of devices brings challenges to microscale joining
technologies. Essentially, effective microjoining has been an integral part of manufacturing for many decades in microelectronics, medical, aerospace, and defense
industries (Zhou and Hu, 2011). Microjoining processes can be grouped like traditional methods, in respect of solid-state bonding, fusion welding, brazing/soldering, and adhesive bonding. Thus, Jain et al. (2013) described microwelding, fusion
microwelding, electron beam microwelding, laser beam microwelding, resistance
microwelding, solid-state microwelding, ultrasonic microwelding, and microjoining
by adhesive bonding. However, as Zhou and Hu (2011) underlined, further down the
road of miniaturization to nanoscale, there is an emerging need to join nanoscale
building blocks, such as nanowires and nanotubes, to form nanoscale devices
and systems, e.g., micro-electro-mechanical systems (MEMS) and nano-electromechanical systems (NEMS), and then to join these to the surroundings integrating them into micro- and macroscale devices and systems. The authors emphasized
that the term “microjoining” is already popular in industries, while “nanojoining”
is relatively new and often used in relation to conventional macroscale welding and
joining. It should be noted, however, that various soldering processes and alloys,
widely used in microelectronics interconnection and packaging, have been modified and further developed for the purpose of nanojoining. Focused electron beam,
widely used in micro- and macrojoining, is also applied to join metallic nanomaterials. Other examples named by Zhou and Hu (2011) include ultrasonic welding,
cold welding, laser welding, resistance welding, etc. The authors also point out the
main challenges of micro- and especially nanojoining technologies, such as surface
roughness and contamination, which significantly increase surface areas and reduce
volumes. These may cause difficulties in the manipulation of nanoscale building
blocks and damage to their internal structure and properties.
1.14 METHODS INCREASING MACHINING ACCURACY
To ensure machining accuracy, a scientific approach is required. It involves the process of identifying and analyzing potential challenges, analysis and deeper understanding of impacts, as well as the development of methods to minimize accuracy
issues (Brecher et al., 2016). For example, it was found that limitation of dynamic
properties for CNC machine tools leads to the contouring error and becomes a vital
issue that may decrease the machining accuracy of high-performance parts with
complex curved surfaces (Jia et al., 2018). An extensive review of ultrafast laser
micromachining accuracy was published by Cheng et al. (2013). It discussed effects
of some very important parameters such as laser pulse duration, plasma and polarization, as well as some techniques employed for the increase of machining accuracy
and throughput. It was shown that the shorter the laser pulse duration, the shorter the
Remanufacturing and Advanced Machining
approaches show sufficient load-bearing capabilities for automotive applications. All
of these methods have individual advantages and disadvantages, and a decision to
apply one or more technologies in a particular production depends on requirements
like production volume, required strength, material flexibility, costs, etc. (Meschut
et al., 2014).
Advancing miniaturization of devices brings challenges to microscale joining
technologies. Essentially, effective microjoining has been an integral part of manufacturing for many decades in microelectronics, medical, aerospace, and defense
industries (Zhou and Hu, 2011). Microjoining processes can be grouped like traditional methods, in respect of solid-state bonding, fusion welding, brazing/soldering, and adhesive bonding. Thus, Jain et al. (2013) described microwelding, fusion
microwelding, electron beam microwelding, laser beam microwelding, resistance
microwelding, solid-state microwelding, ultrasonic microwelding, and microjoining
by adhesive bonding. However, as Zhou and Hu (2011) underlined, further down the
road of miniaturization to nanoscale, there is an emerging need to join nanoscale
building blocks, such as nanowires and nanotubes, to form nanoscale devices
and systems, e.g., micro-electro-mechanical systems (MEMS) and nano-electromechanical systems (NEMS), and then to join these to the surroundings integrating them into micro- and macroscale devices and systems. The authors emphasized
that the term “microjoining” is already popular in industries, while “nanojoining”
is relatively new and often used in relation to conventional macroscale welding and
joining. It should be noted, however, that various soldering processes and alloys,
widely used in microelectronics interconnection and packaging, have been modified and further developed for the purpose of nanojoining. Focused electron beam,
widely used in micro- and macrojoining, is also applied to join metallic nanomaterials. Other examples named by Zhou and Hu (2011) include ultrasonic welding,
cold welding, laser welding, resistance welding, etc. The authors also point out the
main challenges of micro- and especially nanojoining technologies, such as surface
roughness and contamination, which significantly increase surface areas and reduce
volumes. These may cause difficulties in the manipulation of nanoscale building
blocks and damage to their internal structure and properties.
1.14 METHODS INCREASING MACHINING ACCURACY
To ensure machining accuracy, a scientific approach is required. It involves the process of identifying and analyzing potential challenges, analysis and deeper understanding of impacts, as well as the development of methods to minimize accuracy
issues (Brecher et al., 2016). For example, it was found that limitation of dynamic
properties for CNC machine tools leads to the contouring error and becomes a vital
issue that may decrease the machining accuracy of high-performance parts with
complex curved surfaces (Jia et al., 2018). An extensive review of ultrafast laser
micromachining accuracy was published by Cheng et al. (2013). It discussed effects
of some very important parameters such as laser pulse duration, plasma and polarization, as well as some techniques employed for the increase of machining accuracy
and throughput. It was shown that the shorter the laser pulse duration, the shorter the