The purpose of this research is to terminate the burr rejection on compressor driven pulley. The research is undergone using Minitab analysis software to design experiments with three factors and two levels, which is carried out by process capability analysis method. After that process, the experiment was further engaged in normalizing cooling process and optimized cooling process which help to know about the status of material hardness and its machinability. Hardness of forgings was higher at Optimized Conveyor Cooling (56 HRB 65to) and Hardness was getting lower at Normalizing Cooling (47 HRB to 58 HRB). Machinability of normalizing cooling forgings was not good as contrast to the Optimized conveyor cooling forgings. Sipoc approach was taken for detailed analysis. A significant amount of reduction in total machining rejection percentage in addition to the straight savings in incalescence, labour force and tool cost and rework cost. Study the effect of hardness improved material machinability status.

Microperforated panels (MPPs) are promising sound absorbers with significant potential for enhanced performance. Numerous studies have explored ways to improve MPPs by adjusting parameters such as perforation ratio, perforation diameter, panel thickness, air gap thickness, and material choice. Typically, MPPs are installed in front of rigid, flat surfaces; however, the effect of wall shape has been largely unexplored. This study investigates the impact of three different wall shapes—flat, stair-shaped, and concave—on MPP sound absorption. Both MPPs and models of the three wall shapes were 3D-printed, and their sound absorption was evaluated using an impedance tube. The results show that stair-shaped and concave walls provide superior sound absorption, particularly in the low-frequency range, compared to flat walls with the same air gap distance. These findings suggest that non-flat wall designs, such as stair-shaped and concave, can enhance sound absorption at lower frequencies. This study highlights the potential for MPPs to be effectively installed in front of rigid walls or surfaces of various shapes, expanding their applicability across a wide range of acoustic environments.

The rapid urbanization and economic expansion have increased the negative consequences of environmental noise pollution. The sound that originates from various sources comes from distinct spectrums. To address the aforementioned issue, acoustic absorbers were 3D printed with varying infill patterns to absorb sound across a wide range of frequencies. Acoustic absorbers made of polylactic acid/polyhydroxyalkanoates-wood fibers (PLA/PHA-WF) were fabricated using Fused Deposition Modelling (FDM) technology, and their physical, mechanical, water absorption, biodegradation, and acoustic characteristics were measured and discussed. Acoustic absorbers printed with different infill patterns have a slight difference in density due to the size of the pores and the contact sites exhibited by the infill pattern. As a result, acoustic absorbers printed with varying infill patterns allow sound waves to enter and absorb sound at distinct spectrum levels. Modifying the infill pattern also had an effect on mechanical, water absorption, and biodegradation properties with minor deviations. The proposed biodegradable acoustic absorbers made of natural fiber composites and manufactured by FDM can be installed on building walls or roofs depending on the required acoustic absorption spectrum.

Abstract The microperforated panel (MPP) is a unique panel that has evolved from the traditional perforated panel. Previously, the perforated panel was mainly used as a protective cover for porous materials. The MPP absorbs sound through the viscous effect around its perforated holes. However, traditional MPPs are typically made from metallic materials that are not environmentally friendly. In contrast, polylactic acid (PLA) is a biopolymer extracted from natural resources such as corn and sugarcane. When buried in soil, PLA degrades naturally with the assistance of soil bacteria and fungi, making it an eco-friendly choice. In this study, 3D printing method was utilized to produce MPP using PLA as the material. The sound absorption performance of PLA MPP was compared to steel MPP, which served as the benchmark. Interestingly, the sound absorption performance of PLA MPP was found to be comparable to that of steel MPP. This highlights PLA as a viable material for MPP production, aligning with the global goal of environmental preservation and Sustainable Development Goal (SDG) 12, which emphasizes responsible consumption and production.

This study introduces a novel approach using wood fiber/PLA composite microperforated panel (WFCMPP) for indoor sound absorption purposes. WFCMPP, comprising rubber tree chip-derived fibers and a polylactic acid (PLA) matrix, with the dimensions of the rubber tree chip-derived fibers ranging from 0.5 to 1 mm, demonstrated promising sound absorption coefficients comparable to other natural fiber composite microperforated panels. The maximum sound absorption coefficient was recorded at 0.989 with a resonance frequency of 1416 Hz when the wood fiber composition was 30%. The study also investigates the impact of wood fiber composition on sound absorption, revealing a linear relationship between fiber content and both porosity and sound absorption. The peak sound absorption coefficient of WFCMPP remained almost identical at different air gap thicknesses, showcasing the versatility and effectiveness of the samples. Additionally, the performance remained robust even with variations in air gap size. Scanning electron microscope analysis confirms the irregular porous structure and complexity contributing to enhanced sound absorption. WFCMPP presents a sustainable and effective alternative for acoustic applications, combining sound absorption performance with environmental considerations.

This research aims to address the noise pollution by developing an acoustic absorber made of polylactic acid (PLA)/polyhydroxyalkanoates (PHA)-wood fibers (PLA/PHA-WF) by compression molding (CM) and additive manufacturing (AM). Physical, mechanical, thermal, water absorption, and biodegradation properties of the developed acoustic absorbers by CM and AM were characterized and compared. Upon providing an air gap, thin absorbers developed by AM exhibit an increased and narrow acoustic peak than the CM absorbers because of the Helmholtz resonance effect due to the decreased density and increased porosity in the AM absorber. The results also show that the mechanical and thermal properties of the absorbers developed by CM and AM were almost similar and absorber developed by AM shows an increased rate of water absorption and biodegradation compared to absorber developed by CM due to the presence of porosity in the AM structure.

The rapid population growth in urban areas leads to increased waste generation and the need for sustainable waste management solutions to preserve the global environment. In this paper, we present an intelligent garbage collection system for smart city environments, which consists of three key components. First, we propose a novel model to optimize the positioning of garbage bins to prevent both overflow and underutilization. We leverage a fuzzy soft expert set-based solution to identify optimal locations within a selected region. Experimental results demonstrate that our proposed method significantly outperforms manual placement strategies in mitigating issues arising from inappropriate bin placement. Second, we address the problem of improper waste collection from overflowing garbage bins by developing a smart bin system. This system employs a voice-controlled bin that sends automatic alerts to collectors before reaching its full capacity, as well as audio alerts for the public to prevent waste overflow around the bin. Lastly, we integrate a mobile application and cloud-based database to enable real-time monitoring of bin statuses. This comprehensive approach to waste management in urban areas not only enhances the efficiency of garbage collection but also contributes to a cleaner and more sustainable environment.

Microperforated panel (MPP) is considered a unique and promising sound absorber, as its sound absorption performance depends on parameters such as perforation ratio, perforation diameter, and air gap thickness. In this study, the MPP was fabricated through conventional mixing, granulating, and hot compression methods. The MPP was made from coir fiber/polylactic acid (PLA) composite, outside the norm of using metallic materials to produce MPP. The panel's sound absorption performance was measured using an impedance measurement tube and then compared with pure PLA MPP, which was taken as a benchmark for this study for a fair comparison. The MPP produced in this study demonstrated outstanding sound absorption performance due to its porous and tortuous structure. The porous and tortuous structure coincided with the perforated hole mechanism in absorbing sound; thus, the performance was better than pure PLA MPP, which did not possess an apparent porous and tortuous structure. This study proved that natural fiber composite has considerable potential to be used for MPP production, as it is a sustainable and natural resource that brings less harm to the environment compared to the common usage of metallic materials.

Honeycomb structures have a wide variety of applications in engineering, architecture, and transportation. Latticing, facilitated by additive manufacturing (AM), can effectively accelerate development of customizable structures. This paper introduces a systematic experimental approach to investigate the impact of various material extrusion (MEX) factors on the physical and mechanical characteristics of triangular honeycomb lattice-structured Onyx (TM) composites. The experimental study is conducted by varying MEX factors such as layer height, infill density, build orientation, infill pattern, and number of walls and their impact on the physical property (density), mechanical property (compressive strength), and structural property of the lattice structure (structural area deviation). The results highlight that the optimal combination for obtaining the maximum compressive strength is 0.1 mm layer height, 50% infill density, 90 degrees build orientation, rectilinear infill pattern, and a wall count of three. The MEX factors like infill density, build orientation and infill pattern have a significant impact on the physical properties. Furthermore, the lattice-structured Onyx (TM) composite with three walls exhibits buckling phenomenon at a slower rate when compared to the lattice-structured Onyx (TM) composites with one and two walls. The structural area deviation of the integrated lattice is majorly influenced by the layer height and build orientation. The optimized condition for a higher load bearing capability is employed for developing a topologically optimized lattice-structured bracket. It has potential to be used for sports-action cameras, medical/dental instruments, preoperative surgical planning, crowns and bridges, copings and casts.

This study concentrates on the potential recycling and cleaner conversion of marine industry wastes such as crab shell wastes as particles in the development of novel polylactic acid (PLA) biocomposite filaments for 3D printing applications. The filaments were extruded with varying extrusion process parameters such as extruder speed (20, 30, 40, and 50 mm/s), extrusion temperature (170, 175, 180, and 185°C), environmental conditions (no, air, and water medium), and crab shell particle concentration (0, 1, 5, 7, and 10

In craniomaxillofacial surgery the inclusion of lattice structure on the Cranio-implants for the surgical procedure of cranial defects is difficult. Additive manufacturing open ups a huge space for the development of intricate profiles for complex surgical practices. Designing lattice structures with various design topologies has gained more interest in the medical community for reducing the weight of the implants in the cranial region. This research proposes the mimicking of cranial defective portion concerning bone-like porous structure by means of Poly methyl methacrylate (PMMA) material via 3D printing technology. The experiments were optimized by incorporating square-type porous lattice structure in the development of cranial implants. The design-based factors of the unit cell were enhanced with the aid of the Design of experiments (DOE) technique. L9 orthog-onal array is developed by incorporating various design-based factors of the lattice unit cell like unit cell size (mm), skewing angle (degrees), wall thickness (mm), and unit cell orientation (degrees). The experiments are optimized with respect to obtaining better compressive strength and compressive strength/density of the prepared lattice structure incorporated polymeric samples. The result shows that for obtaining the maximum compressive strength in the porous square lattice-structured PMMA compression samples will be a lower cell size of 2 mm, a higher skewing angle of 30 degrees, a higher wall thickness of 1 mm, and a unit cell orientation of 90 degrees. The experimental optimized condition results of the design-based factors achieve the maximum compressive strength and compressive strength/density of 83.37 MPa and 189.73 MPa/g mm-3. The lattice structure orientated with 90 degrees has a significant contribution towards reducing the development of structural deviations of incorporating square lattice structure on the PMMA polymeric material. Therefore, the topologically modified square lattice structure incorporated 3D printed PMMA material has a potential scope for the replacement of conventional maxillofacial cranial implants.

Synthetic fiber is still considered the best sound absorptive material. However, due to the health concern of synthetic fiber usage, researchers are trying to find another viable alternative. A microperforated panel (MPP) is a promising alternative that relies on the concept of a Helmholtz resonator for sound absorption. MPP possessed excellent acoustic resistance and a considerable range of absorption bandwidth. In this paper, MPP made of natural fiber composite was fabricated and its acoustic absorption was measured using a two-microphone impedance tube method as per ISO 10534-2 standard. Later, the tensile strength of the fabricated acoustic absorbers was measured using an Instron Universal Testing Machine as per ASTM D638. The idea of employing additive manufacturing, better known as the 3D printing technique, is proposed to produce lightweight MPP. The 3D printing technique provides design freedom and is less tedious in creating complex and light structures. The 3D printing technique has various important parameters, and infill density is one of the parameters. It was found that the reduction of infill density leads to a decrease of the MPP’s mass and thus, slightly affects the resonance frequency of the MPP, still within the mid-frequency spectrum. It was also noted that the increment of air gap thickness leads to the shifting of MPP’s resonance frequency to a lower frequency range. The tensile strength of the 3D printed samples decreases with a decrease in infill density. A sample with an infill density of 100% has the highest tensile strength of 22 MPa, and a sample with an infill density of 20% has the lowest tensile strength of 12 MPa.

In recent times, Additive Manufacturing (AM) has been applied rapidly in almost all fields. This study was conducted to apply the additive manufacturing into an acoustic application by 3D printing the Micro-Perforated Panels (MPP) through Fused Deposition Modelling (FDM) made of Polylactic Acid (PLA) reinforced with wood fibers. MPP were fabricated by altering its perforation volume. Later, the effect of perforation volume on acoustic absorption of the fabricated MPP was measured using the two-microphone impedance tube method as per ISO 10534-2 standard. The result shows altering the perforation volume affects the acoustic absorption of the MPP. MPP with a thickness of 2 mm and a perforation diameter of 0.2 mm shows the maximum sound absorption coefficient of 0.93 at 2173 Hz. It is made possible to absorb the 3D printed MPP made of natural fiber reinforced composite at different spectrums by altering the perforation volume.

This paper presents the development and performance of micro-perforated panels (MPP) from natural fiber reinforced composites. The MPP is made of Polylactic Acid (PLA) reinforced with Oil Palm Empty Fruit Bunch Fiber (OPEFBF). The investigation was made by varying the fiber density, air gap, and perforation ratio to observe the effect on the Sound Absorption Coefficient (SAC) through the experiment in an impedance tube. It is found that the peak level of SAC is not affected, but the peak frequency shifts to lower frequency when the fiber density is increased. This phenomenon might be due to the presence of porosity in the inner wall of the holes. Increasing or decreasing the air gap and perforation ratio shifts the peaks of acoustic absorption either way.

In recent years, Natural Fibre-Reinforced Composites (NFRC) making its impact in all applications, and they have reached their way into the field of Additive Manufacturing (AM) as well. This increases the demand for natural fibre based filaments in the field of AM. Hence, this research aims to develop filaments made of Polylactic acid (PLA) reinforced with Oil Palm Empty Fruit Bunch Fibre (OPEFBF) and to investigate its physical, thermal and mechanical properties. PLA with 10, 20, 30, and 40 wt.% of OPEFBF were melt blended, hot-pressed, and successfully extruded as filaments. Later, its physical, thermal, water absorption, biodegradation, and mechanical properties are investigated. OPEFBF reinforced filaments show lesser values of densities, increased Tensile Modulus (TM), better bio and thermal degradation compared to the pure PLA. However, its rate of water absorption is high with reduced Tensile Strength (TS) than the pure PLA. Later these filaments reinforced with different OPEFBF contents are 3D printed using Fused Deposition Modeling (FDM) technology. Filaments with lesser fibre content were easy to print. Filaments with 10 wt.% OPEFBF was continuously printed whereas, filaments with higher fibre content clogged in the nozzle. Overall, PLA reinforced with OPEFBF has been developed and successfully applied to the field of additive manufacturing by FDM.

Additive manufacturing (AM) of Natural Fiber-Reinforced Composites through Fused Deposition Modeling is receiving much attention in recent years. AM is very appealing for complex shape structures that can be inconvenient to produce by other methods. In this study, the acoustic panel made from polylactic acid reinforced with wood fiber composite was 3D printed by varying its thickness and infill density. The sound absorption coefficient was measured using an impedance tube. The thin panel with back air gap was found to absorb sound at mid-frequency range resembling the Helmholtz resonator. The absorption performance for the thick panel can be controlled by controlling the infill density of the panel. Customizing the acoustic absorption is therefore possible for panels from biodegradable materials by AM.

In current times, noise pollution is especially apparent in urban areas due to rapid development in transportation, industrialization, and urbanization. The worsening noise pollution is detrimental to human health and behaviour as it can contribute to disorders and psychological disturbance. Thus, noise regulation is crucial and must be addressed with immediate effect. Micro-perforated panels (MPP) can be a potential solution to mitigate noise on a commercial scale. Researchers have addressed the mechanics behind the enhancement of acoustic absorption through micro-perforation and some suggestions have been made, such as the effect of structural variation on sound absorption performance. Hence, this research aims at optimizing the sound absorption performance of an MPP by determining the connection between thickness and perforation size with sound absorption coefficient. Three cases were considered: (i) varying perforation size, (ii) varying thickness, and (iii) varying perforation size and thickness simultaneously. Based on the Maa prediction model, the sound absorption performance for all three cases have been simulated through the MATLAB software. Results show that the increase in both thickness and perforation size together increases the peak value of sound absorption coefficient (SAC). It also shifts the peak towards the higher frequency region and narrows the bandwidth. The findings of this study indicate the potential of thick MPPs as commercial sound absorbers by adjusting the size of perforations. Thicker and sturdier MPPs with optimal acoustic resistance and reactance can act as reliable sound absorbers for sound insulation purposes.

The main aim of this research is to analyse the modal response of an acoustic panel made of Natural Fiber Reinforced Composites (NFRC) by varying the size and shape of perforations in it. NFRC are proved to be excellent acoustic absorbers. Hence, researches have been made on developing an acoustic panel made of NFRC. Acoustic panels with perforations turned out to be successful because of its effective absorption. In general, researchers consider only the effect of size and shape of perforations on the acoustic absorption whereas, leaving away the effect of size and shape of perforations on the modal response. Hence this research has been performed to understand the effect of size and shape of the perforations on the modal response of an acoustic panel made of PI A-OPEFBF composite. Composite were prepared using conventional hot-press techniques. Design of an acoustic panel was made using SolidWorks and the modal response analysis is performed using ANSYS. The result shows increase or decrease in size of the perforation affects the natural frequency of the system. "This research shows the importance of considering the effect of considering the size and shape of the perforations during the development of an acoustic panel.

Natural fiber based filaments are economically, and environmentally friendly and they are sustainable which enables them to be applied in the production of novel composite materials. This research aims to produce 3D printed filaments composed of Poly lactic acid (PLA) reinforced with 5 wt%, 10 wt% and 15wt% of coconut fiber (CF) and coconut shell powder (CSP). These fillers were alkaline and silane treated in order to enhance the thermal properties. These fillers were characterized by FTIR, SEM and TGA analysis. The SEM images show that there are structural changes in the fillers after successive treatments. TGA results shows enhancement of thermal stability for CF by 10 degrees C whereas decreased by 10 degrees C for CSP. These fillers are melt blended with PLA as a polymer matrix and extruded as filaments. The filament which is reinforced with CSP holds good for 3D printing whereas, the filaments reinforced with CF clogged during the process of 3D printing due to the large diameter of the filaments.