Punching Process Research Articles

EVALUATION OF LIFE CYCLE ASSESSMENT IN FURNITURE MANUFACTURING USING THE ANALYTICAL HIERARCHY PROCESS

Environmental issues in the furniture industry are of great importance due to the use of natural materials, such as wood and chemical substances like adhesives and paints. These issues encompass environmental conservation and managing the pollution and waste that is generated. This study adopted an integrated AHP-LCA decision model which helped identify several key factors as higher priorities. These factors include the bio-economic aspects, the production process, wood quality, stable supply of raw materials, technical considerations, and the recycling process. A pairwise comparison of 24 sub-criteria revealed that the quality of wood as a raw material, wood supply management and connections, the punching process, user education and trained workforce, and process design are critical criteria. Prioritizing these factors not only helps in the removal of pollutants, but also enhances the Life Cycle Assessment (LCA) framework in the furniture industry. The Life Cycle Assessment (LCA) results using Sima-Pro software indicated that scenario 1, which involves designing recyclable furniture, has a significant impact on water toxicity and CO2 emissions. Additionally, replacing birchwood as an imported raw material (scenario 2) can help mitigate ionizing radiation effects. Finally, using recycled wood in the furniture manufacturing processes (scenario 3) significantly affects land use and emissions.

Microhole Creation in FDM-Printed Sheet Polymers: A Punching Process Approach

Fused deposition modeling (FDM) 3D printing is one of the additive manufacturing processes that can make components with complex shapes, require no tools, are cheap, safe, and have minimal waste. Despite all the advantages of the FDM process, the inability of this technique to create holes on a micro scale can be a problem and limits its application. In this research, a combination of FDM and machining processes was carried out, where micro holes in FDM printed components were created using a punching process. The punching process is carried out by varying pressure and speed. Furthermore, the diameter of the hole and the quality of the sheared edge of the hole resulting from the punching process were evaluated through observation using an optical microscope. The results show that the holes resulting from the punching process have a better shape and diameter than the FDM process. Then, the analysis of the sheared edge from punching shows that pressure and speed significantly affect the surface quality of the resulting sheared edge, where the quality increases with increasing pressure and speed. In the end, the punching process was proven to create micro-scale holes in FDM-printed polymer, especially at minimum thickness.

A sustainable recycling process and its life cycle assessment for valorising post-consumer textile materials for thermal insulation applications.

The textile industry along with construction, electronics and plastic generate huge amounts of waste posing challenges to the adoption of the circular economy. This research presents a sustainable and low-cost recycling technology for conversion of post-consumer textile (denim) wastes to useful insulation materials. To accomplish the objective, nonwoven materials were produced using varying proportions of post-consumer recycled denim (r-denim) fibre and hollow polyester (PET) fibre using different punch densities in the needle punching process. Kowalski, Cornell and Vining mixture design, a special type of design of experiments, was adopted to develop the samples. Developed nonwoven materials were characterised for thermal resistance and tensile properties. The results show that nonwoven materials containing the minimum proportion (20%) of r-denim fibres exhibited the highest thermal resistance (0.131 W-1m2K). However, by adjusting the process parameter of the nonwovens, that is, the punch density, the same thermal resistance (0.131 W-1m2K) is also achieved even with 39% r-denim fibres. Additionally, the nonwovens produced from this blend proportion (r-denim:PET = 39:61) demonstrate a reasonable strength of 2.43 cN/tex. Environmental benefits of the developed r-denim/PET nonwovens have been evaluated by the life cycle assessment approach. Results show that the use of ~40% r-denim fibre has reduced the environmental burden significantly. Therefore, the nonwoven materials produced from post-consumer textile wastes hold tremendous potential as an alternative to synthetic fibres in thermal insulation applications. This recycling approach has immense potential to contribute to the efficient utilisation of post-consumer textile waste materials paving the way for environmental sustainability.

Study and Optimization of the Punching Process of Steel Using the Johnson–Cook Damage Model

Sheet metal forming processes are widely used in applications such as those in the automotive or aerospace industries. Among them, punching is of great interest due to its high productivity and low operating cost. However, it is necessary to optimize these processes and adjust their parameters, such as clearance, shear force or tool geometry, to obtain the best finishes and minimize crack generation. Thus, the main objective of this research work is to optimize the punching process to achieve parts that do not require subsequent processes, such as deburring, by controlling the properties of the starting materials and with the help of tools such as design of experiments and simulations. In the present study, tensile tests were performed on three steels with different compositions and three sample geometries. The information obtained from these tests has allowed us to determine the parameters of the Johnson–Cook damage criteria. Moreover, punching was performed on real parts and compared with simulations to analyze the percentage of burnish surface. The results obtained show that the methodology used was correct and that it can be extrapolated to other types of die-cutting processes by reducing the percentage of surface fractures and predicting the appearance of cracks. Furthermore, it was observed that clearance has a greater influence than processing speed, while the minimum percentage of the burnish area was observed for the minimum values of clearance.

Thermally stabilized polyacrylonitrile/polyphenylene sulfide composite membranes for efficient emission control in harsh environments

In harsh and complex environments, the emission of polluted air poses significant challenges to traditional filtration systems. In contrast to conventional approaches which primarily involve the incorporation of antioxidants into filter materials, this study introduces a novel methodology. Here, we employed polyacrylonitrile (PAN) as a coating for polyphenylene sulfide (PPS) fibers. Furthermore, we innovatively utilized a needle punching process in conjunction with segmented heat treatment to manufacture PAN-PPS composite filter membranes capable of withstanding extreme environmental conditions. During the segmented heat treatment process, the molecular structure of PAN coating underwent a series of changes, ultimately transforming into a heat-resistant ring trapezoidal structure, providing protection for PPS fibers that are prone to oxidation, and thereby enhancing the structural stability of composite filter membrane. Experimental results demonstrated a significant improvement in the mechanical properties of PAN-PPS composite fabric after segmented heat treatment, with the tensile strength increasing by 71.7 % and the Young’s modulus by 91.6 %. Additionally, the flame retardancy and hydrophobic properties of composite membranes were significantly enhanced, exhibiting the excellent stability and better filtration performance in extreme environments. This approach not only addresses the challenges posed by incorporating nano antioxidants into the spinning process but also significantly enhances the high-temperature resistance of the materials. This enables PAN-PPS composite filter bags to effectively control the emission of polluted gases in extreme environments. Furthermore, the thermal treatment process of the PAN coating is easy to implement and cost-effective, providing a novel strategy for the development of extremely high-temperature resistant filtering materials. This makes it possible to explore the development of flexible, high-performance air filtering materials for extreme environments in the future.

A novel punching process with electronically permanent magnetic technology

A novel punching process with electronically permanent magnetic technology

Low-cost and convenient fabrication of polymer micro/nanopores with the needle punching process and their applications in nanofluidic sensing.

Solid-state micro/nanopores play an important role in the sensing field because of their high stability and controllable size. Aiming at problems of complex processes and high costs in pore manufacturing, we propose a convenient and low-cost micro/nanopore fabrication technique based on the needle punching method. The thin film is pierced by controlling the feed of a microscale tungsten needle, and the size variations of the micropore are monitored by the current feedback system. Based on the positive correlation between the micropore size and the current threshold, the size-controllable preparation of micropores is achieved. The preparation of nanopores is realized by the combination of needle punching and chemical etching. First, a conical defect is prepared on the film with the tungsten needle. Then, nanopores are obtained by unilateral chemical etching of the film. Using the prepared conical micropores, resistive-pulse detection of nanoparticles is performed. Significant ionic current rectification is also obtained with our conical nanopores. It is proved that the properties of micro/nanopores prepared by our method are comparable to those prepared by the track-etching method. The simple and controllable fabrication process proposed here will advance the development of low-cost micro/nanopore sensors.

Design, Fabrication, and Analysis of a Precision Drilling Jig for Waste Reduction: A Low-cost Solution

The modern assemblies of various machines such as engines, gears trains, and body panels require a highly precise drilling operation. These precisely drilled holes not only ensure the efficiency by constrained motions of these machines’ parts but also ensure longer service life. Moreover, precision drilling shall also ensure no subsequent requirement of reaming resulting in time and cost-saving. The precise drilling operation cannot be achieved unless highly precise machinery (CNC) is being utilized requiring higher initial investment (Pkr 1000000), or highly skilled workers demanding about twice the labor than the semi-skilled person. Being a small-sized industry, for profitability, a low-cost solution was proposed in this current work. To obtain precise drilling operation by the application of a drilling jig (Pkr 3000) on the manual bench drill machine (Pkr 15000), by a semi-skilled worker. In this work, a drilling jig has been designed, fabricated, and analyzed. This jig also can rotate the workpiece in clockwise/counter-clockwise directions. The drilled holes measurements provided the evidence that under the spindle speeds of 340, 700, and 1000 rpm, the closer dimensional values (~0.1mm) can be obtained, resulting in the elimination of rework and extra cost, along with the setup-time reduction by eliminating marking and center punching process, with the application of jig. It was concluded that the jig is quite applicable and can be substituted with high-cost CNC machines as a low-cost solution to the local small and medium-scale manufacturing industries.

Effects of multiple hydraulic punching for ultra-deep buried high ground stress powdered coal seam with low permeability

The high ground stress and poor gas permeability of the ultra-deep buried highland stress coal seam make it difficult for conventional unloading and permeability-increasing techniques, such as fracturing or cutting, to achieve the goal of coal seam pressure relief. This article proposes a multi-stage hydraulic punching permeability increasing scheme for the M1-7∼M1-9 gas drainage project of the powdered coal seam with highland stress (44.42 MPa) in tunnel No. 2 of Zhaotong, and studies the effect of cavity formation and gas changes caused by multiple hydraulic punching through theoretical analysis and numerical simulation methods. The gas drainage effect after multiple hydraulic punching was also monitored on-site and systematically compared with natural gas drainage and single hydraulic punching permeability-increasing techniques to determine the optimal solution for multi-stage hydraulic punching. Using the COMSOL numerical simulation software, a coal body model was established based on theoretical analysis. Boundary pressures, ideal gas pressures, and high-pressure water flow pressures were set as boundary conditions to simulate the process of hydraulic punching. The theoretical analysis and numerical simulation were then used to guide on-site experiments. The research results shows that for ultra-deep buried highland stress powdered coal seams, natural gas drainage efficiency is extremely low, and the initial effect of single hydraulic punching permeability increasing is significant, but the fast decay rate of short gas is still due to the time that the cavity formed by hydraulic punching exists. Multiple hydraulic punching effectively alleviates the gas decay rate, and the gas drainage efficiency can reach three times and 22 times that of single hydraulic punching and natural drainage techniques, respectively. When the hydraulic punching interval period is five days and the hydraulic punching frequency is three times, the gas drainage effect is optimal. Multiple hydraulic punching permeability-increasing technologies can provide reference for gas extraction in similar low permeability coal seams with highland stress. The research holds great significance in promoting efficient gas extraction and ensuring the safety construction of gas tunnels.

Influence of the cutting edge preparation of carbide punching tools for punching of ultra-high strength steel strips

In order to ensure a robust punching process of ultra-high strength steel spring strips using carbide punching tools, a high stability of the cutting edge is required. Here the cutting edge preparation process has a significant influence. In the presented study, high-pressure abrasive water jet technology for cutting edge preparation was designed, investigated and analysed. For defining the optimal cutting edge shape regarding stresses, a numerical analysis using LS-DYNA was conducted. Within this analysis, the influence of the cutting edge rounding and symmetry was numerically tested and evaluated. Based on the results, two cutting edge shapes were selected and prepared using the high-pressure abrasive water injection jet technology. The tools were applied in the punching process up to 50,000 strokes in order to analyse the cutting performance and tool wear. With regard to a highly wear resistant tool for punching, a combination of the abrasive water injection jet preparation routine and a CVD diamond coating are under further investigation and first insights are presented additionally.

Visualization of a jet stream group influencing the noise increase phenomena in generated by airflow through a perforated metal plate

The perforated plate is made by a punching process. Because of this manufacturing process, the cross section of holes in a perforated plate varies in the direction of the thickness of the plate. When an airflow passes through a group of holes in a perforated plate, the noise characteristics change depending on the direction of passage. In the case where the cross-sectional area of holes increases in the downstream direction, the aerodynamic noise generated by airflow through holes in perforated plates increases. The cause of the noise increase is considered to be the lock-in phenomenon between the vibration of the plates and the outflow of the vortex. For this to occur, at least seven closely spaced groups of holes are required. In this study, flow visualization using the fog method was performed to clarify the behavior of the jet stream group during the noise increase. The results showed that the vortex outflows at each hole were in opposite phase when the lock-in phenomenon did not occur, but that the vortex outflows at adjacent holes were synchronized when the lock-in phenomenon occurred.

THE INFLUENCE OF THE NON-SYMMETRIC PUNCHING PROCESS PARAMETER ON THE HOLE SHAPE AND QUALITY OF A COMMERCIALLY PURE TITANIUM SHEET

Recently, punching technology has become one of the promising manufacturing techniques for a thin metallic sheet. The processing parameters used in this technique have been recognized to influence the hole shape produced in the working materials. Therefore, it is important to understand the effect of the punching process parameters on the hole shape and quality over the manufactured materials. This study aims to determine the influence of the punching process on the non-symmetrical hole shape and quality over a commercially pure titanium sheet. The effect of punch speed on the punch force and the sheared surface is also studied, by applying the punch velocities of 10, 35 and 70 mm/s. The sheared surface of the hole was examined at its four different sides, namely K (straight), L (outer radius), N (inner radius) and M (straight). The results show uneven distribution of punch strength as detected at the affected region of the non-symmetrical hole. In addition, the punch force increased with the increase of punch speed. Meanwhile, the sheared surfaces on each side were apparently different. The burnish height on the side of the radius was found to be about 0.038 mm higher than that on the straight side. The burnish height on the radius side increases by 0.43 mm with the increasing punch speed from 10 to 70 mm/s. However, the increased punch velocity did not always increase the burr height. The work hardening that occurs on the straight side is smaller by about 15% than the radius side.

Investigation of electromagnetic punching process with adjustable collision velocity for ultra-thin titanium sheet

Investigation of electromagnetic punching process with adjustable collision velocity for ultra-thin titanium sheet

Examination of acoustic properties of polymer-coated nonwoven textile samples

In this study, different types of polymeric layers were coated in different weights (g/m2) on nonwoven fabrics by extrusion process and then, sound absorption and transmission loss properties of each sample were examined. Nonwoven fabrics were produced from polyester (PET) fiber, formed by the carding process and bonded by the needle punching process. These samples were tested between 50-6000 Hz frequency range to reveal the effect of polymer layer type and weight coated on nonwoven fabrics on the sound absorption and transmission loss performance at the low, medium, and high-frequency values. Polymer layers were coated with the weight of 400 gsm and 800 gsm. Nonwoven fabric samples coated with polyethylene or polypropylene layers and nonwoven fabric samples without polymeric coating were tested by using an impedance tube and compared in terms of sound absorption and transmission loss performance. In the test system, two sides of the samples were tested separately. It was seen that the sound absorption performance of the samples changed in case the sound wave was first incident to the polymeric layer or nonwoven layer.

A punching process to join metal sheets and fibre reinforced polymer composites by mechanical interlocking

In the multi-material lightweight design of structural components for the automotive industry, the joint between different materials plays a significant role in reducing vehicle weight without compromising performance or safety. Conventional technologies to mechanically join metals and carbon fibre reinforced polymers result in either drilling a hole in the composite material or increasing the weight of the part because of the fasteners employed. This work presents a new, simple, cost-efficient and non-weight penalizing mechanical joining technology for metal sheets and fibre reinforced polymer prepregs. It consists of a single-step punching process where the metallic sheet is completely perforated, but the prepreg is not. The punch pushes the carbon fibres through the hole in the metal sheet with no or minimal fibre breakage, generating a mechanical interlock which, in turn, increases the shear strength and absorbed energy of the co-cured joint.

Investigation on deformation characteristic of electromagnetic punching process in AA5182 aluminum alloy sheet

Investigation on deformation characteristic of electromagnetic punching process in AA5182 aluminum alloy sheet

Analytical and Experimental Investigation of Product Geometry and Dimensional Accuracy in the Punching Process of AA 1050 and AA 1070 Sheets

Punching is a widely used and economic manufacturing method that needs to be addressed. Especially the forces that occurred during punching and the dimensions of the parts obtained from punching are important in manufacturing processes. This study aimed to examine the cutting forces that occur in the punching process and the dimensional accuracy of the parts. AA 1050 and AA 1070 sheet materials were used in the experimental studies. Five punches with different tip geometries were used in the punching processes. Punching operations were carried out at a constant clearance value and press speed. The geometries of the specimens obtained from the experimental studies were examined using stereo and shuttle-pix microscopes. In addition, punching processes were also investigated using the finite element method. The consistency of the finite element model was analyzed by comparing experimental and numerical studies. The highest cutting force occurred in the use of the flat punch geometry. The lowest cutting force was obtained by using the largest angled punch geometry. It has been determined that the dimensional accuracy of not only the blank but the falling part is better in the use of the flat punch geometry comparing the other punches used. In addition, it was observed that experimental and theoretical studies are compatible with each other. It is thought that finite element software can provide time and cost savings in determining the cutting force of materials.

Punched and folded electrode design for high-rate zinc-ion batteries with high volumetric energy density

Zinc-ion batteries (ZIBs) attract attention as a promising energy storage device due to their safety, eco-friendliness, and low cost. However, the inefficient design of their cathodes limits their large-scale industrial application. To address this challenge, this study creates uniform holes in the graphite current collector via a punching process and coats the electrode active material on both sides of the current collector while maintaining these holes. Additionally, a folded cathode structure is designed to fabricate an efficient cell. Results reveal that the cathodes with uniform pores exhibit improved rate performance and cycling stability due to enhanced ionic behavior. This study presents a practical strategy for designing an efficient cell structure for ZIBs.

Application of a neural network for predicting cutting surface quality of punching processes based on tooling parameters

Punching represents one of the most frequently used manufacturing processes in the sheet metal processing industry. Thereby, one of the most important quality criteria for such punching processes constitutes the geometric shape of the cutting surface. High cutting surface qualities are usually characterized by the lowest possible edge draw in, a high clean cut, as well as a small fracture surface and a low burr height. In this respect, conventional punching processes can only produce clean cut proportions (CCP) up to 20-50% of the sheet thickness. By means of the so called “concave punch nose design” developed at the Institute for Metal Forming Technology, the geometry of conventional punches could be optimized in such a way that the clean-cut proportion along the cutting surface is significantly increased. The findings reported about in this paper show that the quality parameters of the sheared component edges thereby show highly nonlinear relationships to the tooling and sheet metal material parameters used. In order to quantify these effects, the data from several numerical punching simulations is used to pretrain an artificial neural network (ANN). Input data for the neural network included features of the punch geometry, the size of the clearance, the sheet thickness and the material data of the semi-finished product. The output of the neural network is precise predictions of the achievable cutting surface quality parameters. The experimentally validated findings presented in this paper show that the process design for novel punching processes such as cutting with concave punch nose design is possible, when using a modern machine learning approach.

A mechanical interlocking joint between sheet metal and carbon fibre reinforced polymers through punching

The joint between different lightweight materials plays a significant role in multi-material design of structural components for the automotive industry, aiming to reduce the vehicle’s weight without compromising performance or safety. Yet, conventional mechanical joining technologies between metals and Carbon Fibre Reinforced Polymers (CFRP) result in either a hole being drilled in the composite material, leading to damages which reduce the load bearing capacity, or the weight of the part being increased due to the incorporation of fasteners. At the same time, alternative mechanical joining methodologies involve complex and costly processing, hindering their industrial application. This work presents a new, simple, cost-efficient and non-weight penalizing mechanical joining technology between a metal sheet and fibre reinforced polymer prepregs consisting of a single-step punching process. In this process, the metallic sheet is completely perforated, while the prepreg is not. The punch pushes the carbon fibres through the metallic hole, with no, or minimal fibre breakage, generating a mechanical interlock. The shear strength and the absorbed energy of the co-cured joint increase with the incorporation of the mechanical interlocking joint.