73
Contemporary Machining Processes
• Structural difficulties with a high-pressure water supply and cutting heads
• Relatively low wear resistance of the nozzles
• Relatively high energy consumption
• Difference between nominal and real characteristics which may prevent
successful cutting of some materials
• In some small factories, relatively expensive waterjet cutting equipment
may appear unprofitable
Environmental impact of AWJ machining may be analyzed from two perspectives,
namely its application to 6R processes (reduction, repair, reuse, recover, remanufacturing, recycling) and the environmental friendliness of AWJ itself. In this
respect, the abrasive waterjet cutting technology provides some benefits from both
perspectives.
Apart from remanufacturing processes, AWJ can be utilized to crush waste
printed circuit boards for the first time. A recent report (Yang et al., 2021) demonstrated that AWJ cutting was capable of breaking ca. 14-mm thick waste universal
circuit boards into small particles below 1 mm. As a result of one-step processing,
metals and nonmetals were well dissociated. All the cutting debris of the central
processing unit, mainly Cu and Ti particles, were smaller than 150 μm, and metals were completely dissociated. The results implied that AWJ cutting has a huge
potential for enhancement of the material removal indicator and can be a promising
environmental-friendly method for recovering metal resources from e-waste.
On the other hand, as new high-tech abrasives (such as ceramic abrasive, silicon
carbide abrasive) continue appearing, the proportion of abrasives cost in wet abrasive
blasting cleaning is increasing. Thus, reuse of the abrasives becomes more and more
important. To address the issue, a recycling system was proposed by Dong et al.
(2014). It consisted of four parts: abrasive water jet cleaning, abrasive collecting,
waste abrasive separating, and sewage treatment system. The authors demonstrated
that the recycling of abrasives reduced the cost of AWJ cleaning and environment
pollution, making the method more environmentally friendly and more economical. Schramm et al. (2020) reported the recycling potential of suspension fine jet
processing estimated by an integrated technical–economic evaluation. The authors
showed a general particle size reduction, so that without cut material 72%, with
ceramic material 83–87%, and with aluminum 80–81% of the abrasive material can
be reused. Costs of recycling and those of single use of abrasives with subsequent
disposal were analyzed and it proved that recycling abrasives can reduce the costs
by 61.27% compared to a single use of abrasives. In addition, the authors identified
demand for new abrasives as the main variable influencing the result.
1.13 TRENDS IN JOINING TECHNOLOGIES
Böllinghaus et al. (2009) emphasize that joining technology today derived high-technological procedures from conventional process technologies and is rapidly developing toward microjoining and even nanotechnology. They suggest that increasing
attention is paid to optimized material utilization considering local work conditions
Contemporary Machining Processes
• Structural difficulties with a high-pressure water supply and cutting heads
• Relatively low wear resistance of the nozzles
• Relatively high energy consumption
• Difference between nominal and real characteristics which may prevent
successful cutting of some materials
• In some small factories, relatively expensive waterjet cutting equipment
may appear unprofitable
Environmental impact of AWJ machining may be analyzed from two perspectives,
namely its application to 6R processes (reduction, repair, reuse, recover, remanufacturing, recycling) and the environmental friendliness of AWJ itself. In this
respect, the abrasive waterjet cutting technology provides some benefits from both
perspectives.
Apart from remanufacturing processes, AWJ can be utilized to crush waste
printed circuit boards for the first time. A recent report (Yang et al., 2021) demonstrated that AWJ cutting was capable of breaking ca. 14-mm thick waste universal
circuit boards into small particles below 1 mm. As a result of one-step processing,
metals and nonmetals were well dissociated. All the cutting debris of the central
processing unit, mainly Cu and Ti particles, were smaller than 150 μm, and metals were completely dissociated. The results implied that AWJ cutting has a huge
potential for enhancement of the material removal indicator and can be a promising
environmental-friendly method for recovering metal resources from e-waste.
On the other hand, as new high-tech abrasives (such as ceramic abrasive, silicon
carbide abrasive) continue appearing, the proportion of abrasives cost in wet abrasive
blasting cleaning is increasing. Thus, reuse of the abrasives becomes more and more
important. To address the issue, a recycling system was proposed by Dong et al.
(2014). It consisted of four parts: abrasive water jet cleaning, abrasive collecting,
waste abrasive separating, and sewage treatment system. The authors demonstrated
that the recycling of abrasives reduced the cost of AWJ cleaning and environment
pollution, making the method more environmentally friendly and more economical. Schramm et al. (2020) reported the recycling potential of suspension fine jet
processing estimated by an integrated technical–economic evaluation. The authors
showed a general particle size reduction, so that without cut material 72%, with
ceramic material 83–87%, and with aluminum 80–81% of the abrasive material can
be reused. Costs of recycling and those of single use of abrasives with subsequent
disposal were analyzed and it proved that recycling abrasives can reduce the costs
by 61.27% compared to a single use of abrasives. In addition, the authors identified
demand for new abrasives as the main variable influencing the result.
1.13 TRENDS IN JOINING TECHNOLOGIES
Böllinghaus et al. (2009) emphasize that joining technology today derived high-technological procedures from conventional process technologies and is rapidly developing toward microjoining and even nanotechnology. They suggest that increasing
attention is paid to optimized material utilization considering local work conditions