Sheet Metal Working Research Articles

LUBRICATING MATERIALS AS A NOVEL APPROACH TO REDUCE DEFECTS OF MICRO-DEEP DRAWING FORMING PROCESS

The deep drawing forming process, classified under sheet metal working, is a promising and essential metal forming process that has attracted much interest due to its wide application in micro-production. The process parameters, such as the cross-head speed of the machine, have a significant influence on the quality of the product. The impact of two essential parameters was investigated to minimize or eliminate the product's production defects, such as thinning, tearing, and scratching. The first one was the impact of using two types of lubricating oil (grease and wax), and the products were compared with the dry condition (without using a lubricating oil). The second is the impact of changing the cross-head speed of the machine from 5 to 15 mm/min. This work aims to determine the optimum operating condition that prevents any defect in the product. The results showed that using lubricating oil resulted in better product shape, and the wax is better than grease in eliminating product defects. In addition, the results showed that the lower machine speed is preferred for eliminating production defects, where the final product has no obvious thinning, tearing, or scratching. The final product shape was evaluated visually because eye observation is the only way to judge the product shape.

An Exploratory Analysis of the Current Status and Potential of Service-Oriented and Data-Driven Business Models within the Sheet Metal Working Sector: Insights from Interview-Based Research in Small and Medium-Sized Enterprises

Responding to changing value creation processes in the sheet metal working sector, where the complexity and interchangeability of products challenge traditional differentiation strategies, this exploratory analysis examines the integration of service-oriented and data-driven business models as new paths to ensure competitiveness, especially for small and medium-sized enterprises (SMEs). This study aims to capture the current state and challenges associated with the implementation of these business models in this sector. This research was conducted through semi-structured interviews with SMEs in the industry. The findings indicate that service-oriented and data-driven business models are not yet widely adopted and that manufacturing companies require support in their implementation. Fields of action were identified for the industry. These are “Creating awareness and understanding”, “Recognizing added value”, “Increasing company maturity”, and “Understanding the change process”. Cooperation between science and industry is essential in tackling these fields of action to ensure the successful integration of such business models in manufacturing companies. This paper identifies challenges in the fields of action that companies must address through a structured approach, promoting awareness, recognizing value, improving organizational maturity, and understanding the change process to successfully implement service-oriented and data-driven business models.

Identification of threats during the bodywork and paint repair process

Body repairs are often based not so much on procedures as on the experience of the people who perform these repairs. The problem is that heat repairs change the internal structure of the vehicle's skin. When obtaining homologation, manufacturers must prove the specific strength of the materials during crash tests. During a bodywork repair, these parameters may change, and after the repair, there is no obligation to check the strength parameters of a specific element or system. By interfering with the structure, we cannot be sure that we still maintain an appropriate level of security. Therefore, during further tests, together with a team from the Bydgoszcz University of Technology, we plan to check the strength parameters of the vehicle's skin after repair. And what impact on the structure of the material is the duration of individual stages of sheet metal work, the intensity of the current and the temperature to which the material is heated in order to optimize the parameters and increase the level of safety of users.

In-process grain refinement on AA5052-H32 sheet metal in single-stage single point square hole flanging

Hole flanging in sheet metal work can be performed by single point incremental forming. It has been explored by researchers for a decade. Further efforts should be made to decrease the operation time and to improve the mechanical properties of the end product obtained by the forming method. In this direction, a new approach to achieve in-process grain refinement on the aluminium 5052-H32 sheet during single point incremental hole flanging has been presented in this work. Square flanges are formed by a low frequency vibration-assisted method using a novel tool with the single-stage approach. Results show that grain refinement was achieved on the square flanges by the proposed tool and the hardness increased. Moreover, a study on the thickness of the flange, the height of the flange, and surface quality has been presented.

Novel manufacturing of intelligent hierarchical molybdenum-polydopamine hollow nanocarriers for smart coating

Novel hierarchical molybdenum-polydopamine nanocarriers (SMPDA) for hosting the inhibitors in the redesigned molybdenum-polydopamine-Zn2+ (SMPDA@Zn) form were utilized in the epoxy-based (EP) coating formulation to reinforce the barrier / self-healing functions. In the present study advanced FTIR, Raman, XRD, FESEM-EDS, MAP, TEM, BET, ICP-OES, EIS, PDP, OCP, salt spray, cathodic delamination, and pull-off appraisals techniques were employed to assess the influence of hierarchical nanocarriers in the solution and active / passive properties of epoxy coatings. The conspicuous impermeable hybrid films composed of Fe2+/3+-MoO42−, Fe2+/3+-polydopamine, Fe2+/3+-MoO42−-polydopamine and ZnO / Zn(OH)2 on active sites of mild steel in a saline solution comprising the SMPDA@Zn and SMPDA extract would supply %80 and %57 inhibition efficiency, respectively. Active corrosion protection in reference to Rtotal (Rct + Rf) 44463.1, 41879.3, and 9176.3 KΩ cm2 after 72 h immersion for composite and conventional EP coatings by plugging the polymeric film pores as well as healing the defects, intentionally created on the surface were enhanced interestingly up to 4.8 and 4.5 times. The superiority of the incorporated coatings was also obvious in the pull-off and cathodic disbanding tests so a delamination area reduction of %73 was recorded in the presence of the hierarchical nanocarriers. The present study illuminated new horizons in materials science and engineering on the potential usage of durable self-healing primer epoxy-based EPSZ and EPSM coatings in assorted industries like oil and gas pipelines, marine, and offshore infrastructure industries, refineries, petrochemical plants, non-renewable power plants, sheet metal working of shipbuilding, and subsea equipment.

Long-Term Behavior of Clinched Electrical Contacts

Joining by forming operations presents powerful and complex joining techniques. Clinching is a well-known joining process for use in sheet metalworking. Currently, clinched joints are focusing on mechanically enhanced connections. Additionally, the demand for integrating electrical requirements to transmit electrical currents will be increased in the future. This integration is particularly important, for instance, in the e-mobility sector. It enables connecting battery cells with electrical joints of aluminum and copper. Systematic use of the process-specific advantages of this joining method opens up the possibility to find and create electrically optimized connections. The optimization for the transmission of electrical currents will be demonstrated for clinched joints by adapting the tool geometry and the clinched joint design. Based on a comparison of the electrical joint resistance, the limit use temperature is defined for the joining materials used based on the microstructural condition and the aging condition due to artificial aging. As a result of the investigations carried out, reliable current transmission at a constant conductor temperature of up to 120 °C can be achieved for clinched copper–copper joints. In the case of pure aluminum joints and mixed joints of aluminum and copper, long-term stable current transmission can be ensured up to a conductor temperature of 100 °C.

Investigation of annealing on CR-2 grade steel using Taguchi and Taguchi based gray relational analysis

ABSTRACT Low-carbon steels are widely used in domestic appliances, the automobile industry and sheet metal work due to high drawability. Therefore, the cold-rolled sheet products are annealed to improve their ductility. In this paper, annealing parameters, namely, temperature, heating rate and soaking time, have been considered control factors for studying mechanical and microstructure behaviour of the drawing quality (DQ) grade steel. A Taguchi-based L18 orthogonal array is used to find the effect of parameters (temperature, heating rate and soaking time) on the mechanical properties and microstructure characteristics of the DQ grade steel. The optimal value of mechanical properties such as yield strength, ultimate strength and hardness was obtained at 650 °C (temperature), 120 °C/hr (heating rate) and 30 min. (soaking time), whereas the optimal value of elongation was obtained at 750 °C, 40 °C/hr and 60 min. The ANOVA technique is used to summarise the contribution of each variable. Temperature is the most significant parameter for the responses: yield strength, ultimate tensile strength, elongation and hardness with the contribution factor of 46.51%, 82.50%, 82.41% and 84.09% (respectively). Taguchi Grey Relational Analysis (TGRA) was applied to evaluate analytical data results in the highest value of GRG 0.733.

Variants of TIG welding process for improvement of weld penetration depth - A review

This article deals with the various process modifications that occurred in the tungsten inert gas welding process over a decked of time. The conventional TIG welding process usually offers a shallow weld penetration (up to 5 mm). Due to this limited depth of penetration, the industrial applications of this process are very limited and used only for sheet metal working. This article focuses on the various modification that has been made in the conventional TIG welding process to improve the process capabilities. Mainly flux assisted TIG welding, pulse current TIG welding, keyhole TIG welding, multi-electrode TIG welding, TIP-TIG welding process, and their hypothesis responsible to improve the weld penetration were discussed. The effect of various process parameters of these process variants on weld penetration was also discussed. So, this article will help in strengthening the future research trend in TIG welding for enhancement of its industrial application and capability of the process.

Experimental study on designing optimal vibration amplitude in ultrasonic assisted incremental forming of AA6061-T6

Superimposing ultrasonic vibration with metal working process has been proven as effective auxiliary method for improving the quality characteristics. Since, the incremental forming is a state-of-the-art sheet metal working process, number of researches which applied ultrasonic vibration to this process are limited and further studies are still required to basically understand its influence on performance measures. In the present study, an experimental attempt was made to understand how the vibration amplitude influences the forming force, thickness distribution and dimensional accuracy of the samples formed by incremental forming process. In order to do so, series of single factor experiments were designed by variation of vibration amplitude (0, 5, 10 and 15 µm) as main parameter and other parameters were kept constant. The obtained results revealed that increasing the vibration amplitude up to a certain value results in reduction of forming force and dimensional deviation, as well it results in thinning in critical region. At the end of the work, an optimization framework was designed to find interaction effect of process factors with achieving regarding minimized process time as well desired sample quality. It is found from optimization results that superimposing high vibration amplitude provides condition for obtaining minimum process time as well desired quality characteristic of workpiece.

Sheet Metal Working Innovations Expo

Blechexpo will take place in Germany for the 15th time from 26-29 October. Exhibitors will be attending from across the sheet metal working industry

Methodology for the design of a reconfigurable guillotine shear and bending press machine (RGS&BPM)

Purpose In manufacturing, dedicated machine tools and flexible machine tools are failing to satisfy the ever-changing manufacturing demands of short life cycles and dynamic nature of products. These machines are limited when new product designs are introduced. The solution lies in developing responsive machines that can be adjusted or be changed functionally when these change requirements arise. These machines are reconfigurable machines which are becoming the new focus, as they rapidly respond to product variety and volume changes. A sheet metal working machine known as a reconfigurable guillotine shear and bending press machine (RGS&BPM) has been developed. The purpose of this paper is to present a methodology, function-oriented design approach (FODA), which was developed for the design of the RGS&BPM. Design/methodology/approach The design of the machine is based on the six principles of reconfigurable manufacturing systems (RMSs), namely, modularity, scalability integrability, convertibility, diagnosability and customisability. The methodology seeks to optimise the design process of the RGS&BPM through a design of modules that make up the machine, enable its conversion and reconfiguration. The FODA is focussed on function identification to select the operational function required. Two main functions are recognised for the machine, these being cutting and bending; hence, the design revolves around these two and reconfigurability. Findings The developed design methodology was tested in the design of a prototype for the reconfigurable guillotine shear and bending press machine. The prototype is currently being manufactured and will be subjected to functional tests once completed. This paper is being presented not only to present the methodology by to show and highlight its practical applicability, as the prototype manufacturers have been enthusiastic about this new approach. Research limitations/implications The research was limited to the design methodology for the RGS&BPM, the machine which has been designed to completion using this methodology, with prototype being manufactured. Practical implications This study presents critical steps and considerations in the development of reconfigurable machines. The main thrust being to explore the best possibility of developing the machines with dual functionality that will assist in availing the technology to manufacturer. As the machine has been development, the success of the design can be directly attributed to the FODA methodology, among other contributing factors. It also highlights the significance of the principles of RMS in reconfigurable machine design. Social implications The RGS&BM machine is an answer for the small-to-medium enterprises (SMEs), as the machine replaces two machines with one, and the methodology ensures its affordable design. It contributes immensely to the machine availability by eliminating trial and error approaches. Originality/value This study presents a new approach to the design of reconfigurable dual machines using principles of RMS. As the targeted market is the SME, it is not limited to that as any entrepreneur may use the machine to their advantage. The design methodology presented contributes to the body of knowledge in dual reconfigurable machine tool design.

Stamping Monitoring by Using an Adaptive 1D Convolutional Neural Network.

Stamping is one of the most widely used processes in the sheet metalworking industry. Because of the increasing demand for a faster process, ensuring that the stamping process is conducted without compromising quality is crucial. The tool used in the stamping process is crucial to the efficiency of the process; therefore, effective monitoring of the tool health condition is essential for detecting stamping defects. In this study, vibration measurement was used to monitor the stamping process and tool health. A system was developed for capturing signals in the stamping process, and each stamping cycle was selected through template matching. A one-dimensional (1D) convolutional neural network (CNN) was developed to classify the tool wear condition. The results revealed that the 1D CNN architecture a yielded a high accuracy (>99%) and fast adaptability among different models.

Optimization of process parameters of electrical discharge machining of fabricated AA6082 – ALN

The non-conventional machining methods are used for machining very hard materials and for making difficult shapes. Electrical discharge machining (EDM) process is one of the most commonly used nonconventional machining processes for machining hard, brittle materials like composites. It is commonly used in die making industries for developing complex profiles in dies related to sheet metal work etc., It is commonly used for machining metal matrix composites which are very hard materials. Aluminium based metal matrix composites are widely used in aeronautical and defence parts because of their advanced properties like high strength to weight ratio, etc. At first the material was fabricated using stir casting set up which was the part of research work. The work piece material selected in this study was Aluminium alloy 6082 and 10% Aluminium nitrite based metal matrix composite which was fabricated by stir casting process with the help of newly developed stir casting set up. After fabrication, the characterization of samples was done using SEM and mechanical. The EDM process was selected for machining composite samples with input parameters like gap current (A), pulse on time (μs) and duty factor. In this machining process the output response was material removal rate. The optimization of process parameters was done using Taguchi method with the help of ANOVA test and S/N ratio. Analysis of variance was performed to find the significance of machining parameters in this experimental work.

Coaxial camera-based monitoring of fiber laser cutting of thick plates

Laser cutting is a conventional and well-established industrial process within the sheet metal working domain. However, processing of thick plates remains a major problem due to the limited process window. Real-time monitoring for adaptive control might significantly decrease the risk of a cut fail. Up to this point, most studies were mainly focused on the design of monitoring systems for laser cutting with CO2 lasers and limited to either fusion or flame cutting. Nowadays, laser cutting by means of fiber lasers has become the industrial method of choice, however, no tailored generic monitoring solutions for this process have yet been reported in the literature. This paper investigates a coaxial camera-based monitoring system for 4 kW ytterbium fiber laser cutting of 15 mm mild steel and 12 mm stainless steel plates. Experiments at various cutting speeds, resulting in different cut edge quality outcomes, have been conducted. Intensity, geometrical and variability features of the obtained images have been calculated and analyzed. The correlation between the cut specimen quality and process images obtained by means of a high-speed visual camera is discussed for both fusion and flame cutting.

Real-time continuous estimation of dross attachment in the laser cutting process based on process emission images

Laser cutting of metals has become the reference manufacturing technology in sheet metal working thanks to the flexibility and the increased productivity it offers when compared with other competitive technologies. Considering, in particular, the fusion-cutting mode, i.e., when nitrogen is used as an assisting gas, different aspects contribute to the process quality among which dross attachment plays the most important role. To cope with the related time-dependent deterioration of the process quality and to obtain an online adaptation of the process parameters for different working conditions, a closed-loop dross regulation system is needed. To realize it, a reliable, continuous, and accurate estimation of the dross is mandatory. This work focuses on this challenging problem, presenting and comparing different approaches to estimate the dross attachment based on the process emission collected by a coaxial camera. Specifically, a method which relies on the accurate analysis of the process emissions for determining an effective classification method is compared with a deep-learning approach based on convolutional neural networks. The obtained results, validated in real experimental conditions, confirm the possibility to accurately estimate the presence of significant dross attachment in real-time and open the way to the design of a closed-loop control algorithm for the real-time regulation of the dross attachment formation and consequently of the process quality.

A General Framework for Sustainability Assessment of Sheet Metalworking Processes

The sheet metalworking industries possess minimal knowledge in the area of sustainability despite having served as sub-contractors to various industrial sectors. This also highlights that suitable indicators for measuring the sustainability performance of sheet metalworking operations are poorly addressed. As sustainability assessment is regarded as a vital part of sustainable development, this paper has been aimed at establishing a general framework for sustainability assessment of sheet metalworking processes. The main attention was paid to two important processes—the cutting operations with a CNC turret punch press machine and sheet metal bending operations with CNC press brake machine. Stepwise guidelines to implement the proposed framework in sheet metalworking industries are consequently presented. Besides, this study contributes to developing an applicable sustainability indicator set for assessing such manufacturing processes. It makes a valuable contribution to advancing the narrow body of knowledge on the under-researched scope.

Development of part families for a reconfigurable machine

Purpose Reconfigurable machines tools (RMTs) are gaining momentum as the new solutions to customised products in the manufacturing world. The driving force, among others, behind these machines is the part envelope and the part family of products that they can produce. The purpose of this paper is to propose a new class of RMT known as a reconfigurable guillotine shear and bending press machine (RGS&BPM). A part family of products that this machine can produce is developed using hierarchical clustering methodologies. The development of these part families is guided by the relationship of the parts in the family in terms of complexity and geometry. Design/methodology/approach Part families cannot be developed in isolation, but that process has to incorporate the machine modules used in the reconfiguration process for producing the parts. Literature was reviewed, and group technology principles explored, to develop a concept that can be used to develop the part families. Matrices were manipulated to generate part families, and this resulted in the development of a dendrogram of six possible part families. A software with a graphic user interface for manipulation was also developed to help generate part families and machine modules. The developed concept will assist in the development of a machine by first developing the part family of products and machine modules required in the variable production process. Findings The developed concepts assist in the development of a machine by first developing the part family of products and machine modules required in the variable production process. The development of part families for the RGS&BPM is key to developing the machine work envelope and modules to carry out the work. This work has been presented to demonstrate the importance of machine development in conjunction with a part family of products that the machine will produce. The paper develops an approach to manufacturing where part families of products are developed prior to developing the machine. The families of products are then used to develop modules that enable the manufacture of the parts and subsequently the size of the machine. Research limitations/implications The research was limited to the development of part families for a new RGS&BPM, which is still under development. Practical implications The study reflects the development of reconfigurable machines as a solution to manufacturing challenges in terms of group technology approaches adopted in the design phase. It also highlights the significance of the concepts in the reconfigurable machine tool design. The part families define the machine work envelop and its reconfiguration capability. Social implications The success of the research will usher an alternative to smaller players in sheet metal work. It will contribute to the easy development of the machine that will bridge the high cost of machine tools. Originality/value The study contributes to the new approach in sheet metal manufacturing where dedicated machines may be substituted by a highly flexible reconfigurable machine that has a dual operation, making the investment for small to medium enterprises affordable. It also contributes to the body of knowledge in reconfigurable machine development and the framework for such activities, especially in developing countries.

Design and Analysis of Progressive Die for Chain Link Plate

Progressive die follows a sequence of processes in a single die at two or more stations. Design of progressive die is an essential phase in sheet metal manufacturing. Small error at any workplace causes huge manufacturing downtime due to die failure. In this analysis, current die design has low production rate when using multiple stations for sheet metalworking. Each process produced by multiple stations, which increases the loss of time. However, the choice of proper materials for sheet metal plate has become one of the vital features of progressive die design. Due to its long die life has become a requirement for lowering the cost of sheet metal mechanisms. The punch has very short life cycles. The purpose of this paper is to design a new 3D modelling of sheet metal forming die, to optimise a new chain link plate material to improve the performance of the punch component and to analyse the sheet metal punch to increase the punch lifetime cycle. The analysis was conducted by using ABAQUS/CAE to analyse the maximum and minimum stress of punch. The materials used are stainless steel, nickel plate and mild steel. The result of maximum stress obtained from ABAQUS/CAE is used in stress-lifetime prediction calculation. Based on the theory of stress-lifetime prediction, the lower the stress required to deform a material, the longer the life cycle of the punch. From this calculation, we can identify which material is the most suitable for chain link plate production.

Micro-forming analysis of ultra-thin brass foil

ABSTRACTForming process in sheet metal working refers to the manufacturing of products by deforming the material in the required die cavity without being broken or local necking. Defects such as wrinkling, local necking, and cracking may occur during the process. These are the results of either reduction or increase in sheet thickness while the material is being stretched inside die cavity. Prevention of defects is important during forming and is challenging if the thicknesses of forming sheets is less than 100 microns. These sheets are applied in the manufacturing of components having two dimensions of less than millimeter size, an operation known as micro-forming. Miniaturization has attracted many fields such as medical instrumentation, mobile manufacturing, automotive, and aerospace. Appropriate strain distribution in forming ensures products with better quality. Forming limit diagram (FLD) has been invented to plot major and minor strains along with forming limit curves. In other words, FLD shows wrinkling, localized necking as well as safe zones with various strain paths, and it proves to be a basic tool for understanding rupture characteristics of the material. There are three approaches for plotting FLD such as empirical (analytical), numerical, and experimental. The research work presents experimental micro-forming investigations on an ultra-thin brass sheet of 90 microns, to plot FLD, using the limit dome height test according to ASTM E2218-02 standard. The experimental setup was designed and developed to micro-form standard specimens applying 15 mm hemispherical punch. FLD plotted with experimental and empirical approaches shows agreement on failure limit curve.

Online Capacity Brokerage

An Estonia-headquartered business is bringing customers for, and suppliers of, sheet metal work together via an online quotation platform. Andrew Allcock spoke to one of the company’s founders