Optimization of Laser-Assisted Polypropylene Aluminum Joining

in Applied Sciences (2023), 13

Laser joining of polymers to metals is a rising research subject due to the potential of considerably reducing the weight of structures. This article deals with the laser joining process between ... [more ▼]

Laser joining of polymers to metals is a rising research subject due to the potential of considerably reducing the weight of structures. This article deals with the laser joining process between polypropylene and aluminum. Without pre-treatment, laser joining of these materials is not feasible, and the method applied in this study to circumvent this issue is a surface modification of aluminum with a pulsed laser to create mechanical interlocking for the heat conduction laser joining technique. Different patterns and various laser parameters are analyzed with the design of experiments to best understand the effects of each parameter along with microscopic observations. It is found that engraving weakens the mechanical properties of the aluminum samples. The compromise between the engraving depth and the mechanical properties of the samples is optimized, and the engraving process with a 0.28 mm line width, 27.3% density and 150 mm/s speed provides the highest mechanical performance of the assembly with minimum degradation of aluminum samples. Moreover, by adjusting the laser power and using power modulation below 300W, the decomposition of polypropylene occurring at high temperatures is reduced to a minimum. After the final optimization, the joined samples reliably withstand a maximum force of 1500 N, which is, approximately, a shear strength of 20 MPa. [less ▲]

Artificial Intelligence Based Robotic Automation of Manual Assembly Tasks for Intelligent Manufacturing

in von Leipzig, Konrad; Sacks, Natasha; Mc Clelland, Michelle (Eds.) Smart, Sustainable Manufacturing in an Ever-Changing World (2023)

Increasing product customization and shortening product life cycles in an ever-changing world is challenging for automation. This is especially true for assembly tasks, requiring a high level of ... [more ▼]

Increasing product customization and shortening product life cycles in an ever-changing world is challenging for automation. This is especially true for assembly tasks, requiring a high level of perception, skill, and adaptability. With the rise of smart manufacturing, intelligent manufacturing, and other aspects related to Industry 4.0, the hurdles for automation of the aforementioned tasks are getting reduced. Especially Artificial Intelligence (AI) is expected to enable smart and flexible automation since it is possible to deduct decisions from unknown multidimensional correlations in sensor data, which is critical for the assembly of highly customized products. In this research paper, three different conventional and AI-based glue detection models are proposed with the target to automate a gluing process in a manual assembly of highly customized products in a batch size one production scenario. A conventional, one-dimensional rule-based model, and two hybrid models using a support vector machine image classifier (SVM) and either Tamura features or convolutional neural network (CNN) feature extraction are presented and compared. The obtained results demonstrate the efficiency and robustness of AI-based algorithms, as the CNN and SVM hybrid model outperforms the other two approaches achieving a prediction accuracy of >99\% at the fastest classification speed. [less ▲]

The durability of stainless steel-polyamide laser joined assemblies

in Procedia CIRP (2022), 111

Adaptive model to increase resilience for emerging supply chains within the circular economs - 'Zirkelmesser' an innovative case study

in Procedia CIRP (2022)

Variations in quantities, qualities and time availability of input materials pose a major risk to circular supply chains (CSC) and require new models for creating and evaluating adaptive and resilient CSC ... [more ▼]

Variations in quantities, qualities and time availability of input materials pose a major risk to circular supply chains (CSC) and require new models for creating and evaluating adaptive and resilient CSC in the circular economy (CE). This can be achieved by consistently modelling the overarching relationship between resource input- and output streams, without neglecting the associated risks. The model proposed below consists of five components which are based on five resilience requirements for SCs and provides a data-based recommended course of action for managers at a low entry-barrier. It consists of a CSC visualization, a safety stock calculation, a risk monitoring for each SC node, a reporting logic, and a measurement catalogue. The inspiration for this model came from an innovative case study (“Zirkelmesser”) in the metal processing industry in which secondary products and materials are used to produce new products. Here, the problem of maintaining the resource supply arose and led to resilience issues. The mentioned case study is used as an application example for the model application and helps to make emerging circular supply chains predictable and better manageable, thus increasing their resilience. [less ▲]

Intuitive human-robot interaction using augmented reality: A simulation study on KUKA IIWA robot

in SSRN (2022, April 06)

Laser welding of copper to aluminum with spiral trajectory and identification of excessive aluminum melting

in Journal of Laser Applications (2022)

Laser welding of copper and aluminum is challenging due to the formation of complex intermetallic phases. Only a defined amount of Al and Cu can be melted because of the limited solubility of Al–Cu ... [more ▼]

Laser welding of copper and aluminum is challenging due to the formation of complex intermetallic phases. Only a defined amount of Al and Cu can be melted because of the limited solubility of Al–Cu systems. Finding the optimum melting is critical for a strong joint. Optical emission during the welding process contains the metal vapor of Al metal that is being welded. This is a good indicator for monitoring the welding process. This research paper focuses on the optical emission of Al from the bottom sheet during welding of Cu (top) and Al (bottom) in overlapped configuration for a spiral trajectory. The emitted signal in the range of 395 nm (±3 nm) from the bottom sheet of aluminum is used to identify excessive Cu–Al welding. The tensile shear strength, microstructure, and welding signal in the time domain for optimum and excessive weld conditions are investigated. In this study, a technique using a photodiode is shown to identify the excessive melting of Al during the welding process in real time. [less ▲]

Bead Geometry Prediction in Laser-Wire Additive Manufacturing Process Using Machine Learning: Case of Study

in Applied Sciences (2021), Volume 11(Issue 24),

In Laser Wire Additive Manufacturing (LWAM), the final geometry is produced using the layer-by-layer deposition (beads principle). To achieve good geometrical accuracy in the final product, proper ... [more ▼]

In Laser Wire Additive Manufacturing (LWAM), the final geometry is produced using the layer-by-layer deposition (beads principle). To achieve good geometrical accuracy in the final product, proper implementation of the bead geometry is essential. For this reason, the paper focuses on this process and proposes a layer geometry (width and height) prediction model to improve deposition accuracy. More specifically, a machine learning regression algorithm is applied on several experimental data to predict the bead geometry across layers. Furthermore, a neural network-based approach was used to study the influence of different deposition parameters, namely laser power, wire-feed rate and travel speed on bead geometry. To validate the effectiveness of the proposed approach, a test split validation strategy was applied to train and validate the machine learning models. The results show a particular evolutionary trend and confirm that the process parameters have a direct influence on the bead geometry, and so, too, on the final part. Several deposition parameters have been found to obtain an accurate prediction model with low errors and good layer deposition. Finally, this study indicates that the machine learning approach can efficiently be used to predict the bead geometry and could help later in designing a proper controller in the LWAM process. [less ▲]

Bead Width Prediction in Laser Wire Additive Manufacturing Process

in Mbodj, Natago Guilé; Plapper, Peter (Eds.) Bead Width Prediction in Laser Wire Additive Manufacturing Process (2021, October 22)

In laser wire Additive manufacturing (LWAM), the final geometry is produced using layer-by-layer deposition principle of beads. To achieve good geometrical accuracy of the final product, proper ... [more ▼]

In laser wire Additive manufacturing (LWAM), the final geometry is produced using layer-by-layer deposition principle of beads. To achieve good geometrical accuracy of the final product, proper implementation of the bead geometry is essential. The process parameters have a direct influence on the bead geometry, thus to the printed part. In this paper, we propose a bead width prediction model to improve deposition accuracy. A regression algorithm is applied to the experimental results to predict the bead width dimension. Bead prediction equation relating the bead width growth for each layer is obtained for a given set of process parameters. The prediction equations show similar evolution trends and confirm the influence of deposition process parameters on the bead width. The proposed method demonstrates a prospective insight on a more proper selection of process or physical parameter intervening in laser wire additive manufacturing process. [less ▲]

Value Stream Mapping (VSM) to Evaluate and Visualize Interrelated Process-Chains Regarding Circular Economy

in Advances in Production Management Systems. Artificial Intelligence for Sustainable and Resilient Production Systems (2021, August 31), 633

The concept of circular economy (CE) aims to close and slow resource loops without neglecting the goals of sustainable development. Recently, the concept received encouraging attention among researchers ... [more ▼]

The concept of circular economy (CE) aims to close and slow resource loops without neglecting the goals of sustainable development. Recently, the concept received encouraging attention among researchers and business experts to be a convenient solution to move away from the finite linear economy concept to a more sustainable solution. However, this change of paradigm is only possible if we consider systems in a holistic manner and can localize the preventing hurdles. Value stream mapping (VSM) is a commonly known lean method, used to develop current state visualization of product and information flows within organization, helping to seek weaknesses and improve process flows. The motivation of this paper is a new C-VSM model, which enables its users to evaluate and visualize connected process-chains regarding CE on different levels in a holistic manner. For this purpose, the traditional VSM model was adapted towards the needs and requirements of CE through the application of a new representation method, additional indicators, and an appropriated evaluation system. C-VSM is in line with the current political and industrial objectives to apply CE principles by enabling a holistic reflection and consideration of supply-chains (SCs) on different levels. The model itself is validated through an extensive cross-company case study. [less ▲]

An Innovative Strategy Allowing a Holisitic System Change towards Circular Economy within Supply-Chains

in Energies (2021), 14(14),

: The concept of the circular economy (CE) is receiving encouraging attention among scholars and practitioners, as a convenient solution to move away from the linear economy concept without neglecting the ... [more ▼]

: The concept of the circular economy (CE) is receiving encouraging attention among scholars and practitioners, as a convenient solution to move away from the linear economy concept without neglecting the goals of sustainable development. The main goals of the CE are the closing of resource loops and the keeping of resources in the system for as long as possible at the highest utility level. However, as a result of the lack of internationally accepted definitions of the CE and several unsolved barriers, an excessive and inconsistent number of different CE applications exist. Most fields are mainly focusing on making a linear system circular instead of applying the CE principles in a holistic way. This paper presents a strategy to close the mentioned inconsistency gap, by contrasting currently discussed CE barriers and goals and thereof deriving two areas with a need for action (1. identifying the needed collection, sorting, and recovery infrastructure, and 2. developing circular product design guidelines). The strategy itself consists of connecting these two areas through an improved information exchange between the end-of-life (EOL) and beginning-of-life (BOL) of products. The result is CE design guidelines which are in accordance with the available or needed collection, sorting, and recovery infrastructure. The proposed strategy presents an innovative solution to apply CE principles in a holistic manner, based on EOL-driven product design. [less ▲]