Metal Forming With Laser Origami: Parameter Analysis and Optimization

Laser origami is a metal forming process where an initially planar sheet is transformed into a target three-dimensional (3D) form through cutting and folding operations executed by a laser beam. A key challenge in laser origami is to determine the locations of the cuts and folds required to transform the planar sheet into the 3D target shape. The region of the planar sheet that can be transformed into the target shape through these cuts and folds is denoted as the net. This paper presents a method to determine optimal net(s) for laser origami based on criteria including minimum energy usage, minimum fabrication time, minimum error in the fold angles, and minimum material usage. The 3D target shape is given as a polygonal mesh. To generate a net, each edge in the mesh must be classified as a cut or a fold. The energy, time, and other parameters associated with cutting or folding each edge are determined using experimentally calibrated formulas. A search algorithm is subsequently implemented to find combinations of cut and folded edges that provide an optimal set of nets for the given 3D target shape based on a cost function. Nets that are disconnected or have overlapping regions are discarded since they are invalid for laser origami. The method is demonstrated by applying it to different target shapes and cost functions.

3D Digital Manufacturing Applied on Drilling of 7050-T651 Aluminum Performed by Robot

With advances in automation, industry seeks for optimization while new products are developed and manufacturing processes are becoming smarter. In this sense, virtual manufacturing validations have been demanded for reducing the cost with physical prototypes, ensuring ergonomically safe processes and increasing the quality of processes by emulating it realistically, levering automation utilization in industry environments with a faster and safer manner. By that, this research proposes the use of Tecnomatix Siemens® PLM software for process simulation of 7050 aluminum drilling, material which is widely used in aerospace industry, allowing the evaluation of complexes scenarios with multi-robot integration and its conditions and variables, in order to improve the machining process and its aeronautical structural assemblies. Thus, this research provided a relevant contribution regarding the analysis of main process parameters to obtain an efficient sequence of drilling, its productivity and ergonomic conditions.

Process Capability Based Tolerance Allocation in Pneumatic Percussive Riveting

Pneumatic percussive riveting is an important way to join the sheet metals. In order to ensure the load transfer and the fatigue performance of riveted joint, the interference of the rivet/hole is strictly specified. The interference of the rivet/hole is highly correlated with the process capability of the pneumatic hammer and the diameter of the pre-hole. It is a critical step to choose the appropriate pneumatic hammer to ensure the interference requirements. Energy per blow of the pneumatic hammer is a proclaimed parameter from the riveting hammer manufacturer. It is difficult for the designer to choose the riveting hammer in practical riveting scheme based on energy per blow. Tolerance analysis is an efficient way to model the manufacturing variation and implement process control. This paper presents the tolerance allocation of the pneumatic percussive riveting based on the process capability of the pneumatic hammer. In order to obtain the designed interferences of the rivet/hole, a tolerance chain is built with the process capability of the pneumatic hammer, the diameter of the pre-hole and the diameter of the rivet shank. The process capability of the pneumatic hammer is represented with the interferences of the rivet/hole after riveting. It is an intuitive parameter for the designer to choose the riveting hammer in practical riveting scheme. The process capability of the pneumatic hammer is obtained from the designed riveting experiments with the pneumatic percussive riveting platform. The diameter of the pre-hole affects the interference of the rivet/hole also. The tolerance for manual hole-drilling should be determined to assure the interference requirements and high drilling operation efficiency simultaneously. The variation of the pre-hole is obtained from the manual drilling experiments and diameter measurements. Different hole-drilling results in different mating conditions between the pre-hole and the rivet. The fit conditions of different pre-holes are modeled and the final interferences after riveting are analyzed. Worst case method and statistical analysis method are two common methods for tolerance analysis. For the manual hole-drilling and the pneumatic percussive riveting, worst case method is employed to analyze the constructed tolerance chain in order to accomplish the interferences of the rivet/hole. The different analyzed dimensions, rivet-hole clearances and pre-hole drilling variation, are investigated respectively. The reported work enhances the understanding of the tolerance allocation for the pneumatic percussive riveting. The interference based process capability of the pneumatic hammer provides good reference for pneumatic hammer choosing in riveting scheme. The reported tolerance chain of the interference could be used for the tolerance determination of manual hole-drilling with good quality and high efficiency.

Enhancing the Steel Tube Manufacturing Process With a Zero Defects Approach

The continuous thrive for working safety, customer satisfaction and increasing profits for companies has led to numerous manufacturing and management strategies. One of the most promising strategies nowadays is Zero Defects that focuses on the elimination of defected parts in the manufacturing processes. The benefits of Zero Defect implementation in the manufacturing industry are mainly related to the reduction of scrap material, and everything that does not bring any added value to the product. The result is a reduction of the company’s expenditure for dealing with defective products. In spite the concept not being new, the practical application of such strategies were limited by technological constraints and high investment costs. With the Industry 4.0 evolution, some Zero Defects concepts are more accessible due to the availability of sensors and data related techniques such as Machine Learning and Big Data although a lot of work is still required for component integration to enhance the capability of the heterogeneous technologies. The quality of the steel tubes is evaluated by sampling and relies on the expertise of the operators for checking for nonconformities. When a defect is detected, the process parameters are adjusted based on prior experience. However, since this is a continuous process, the delay between the appearance of a defect in the process and its awareness leads to a considerable amount of produced scrap material. Worst-case scenario, the defective product can be delivered to the customer damaging the customers trust and leading to additional replacement costs. This paper addresses the application of the Zero Defects approach to the steel tube manufacturing industry. This approach is part of the Zero Defects Manufacturing Platform EU project that is based around a Service Oriented Architecture and microservices approach capable of building, running and managing specific use-case oriented software applications called zApps. The Zero Defects methodology to design a zApp based on key criteria for the steel tube industry is described. Additionally, the envisioned zApps to monitor all the produced steel tube during the manufacturing process are detailed. The inspection systems uses a scanning camera and a laser profile scanner to capture the steel tube defects during manufacturing and prior to packaging. Although the ultimate goal is to eliminate the cause of the defective products, the objective of the zApp is to increase the number of detections of defective products based on industry standards and reduce the amount of generated scrap material.

Digital Twin: Collaborative Virtual Reality Environment for Multi-Purpose Industrial Applications

Industrial Digital Twins (DT) is the precise virtual representation of the manufacturing environment and mainly consists of the system-level simulation, which combines both manufacturing processes and parametric models of the product. As being one of the pillars of the Industry 4.0 paradigm, DT-s are widely integrated into the existing factories, enhancing the concept of the virtual factories. View from the research perspective is that experiments on the Internet of Things, data acquisition, cybersecurity, telemetry synchronization with physical factories, etc. are being executed in those virtual simulations. Moreover, new ways of interactions and interface to oversee, interact and learn are being developed via the assistance of Virtual Reality (VR) and Augmented Reality (AR) technologies, which are already widely spread on the consumer market. However, already, VR is being used widely in existing commercial software packages and toolboxes to provide students, teachers, operators, engineers, production managers, and researchers with an immersive way of interacting with the factory while the manufacturing simulation is running. This gives a better understanding and more in-depth knowledge of the actual manufacturing processes, not being directly accessing those. However, the virtual presence mentioned above experience is limited to a single person. It does not enable additional functionalities for the simulations, which can be re-planning or even re-programming of the physical factory in an online connection by using VR or AR interfaces. The main aim of the related research paper is to enhance already existing fully synchronized with physical world DT-s with multi-user experience, enabling factory operators to work with and re-program the real machinery from remote locations in a more intuitive way instead thinking about final aim than about the process itself. Moreover, being developed using real-time platform Unity3D, this multiplayer solution gives opportunities for training and educational purposes and is connecting people from remote locations of the world. Use-cases exploits industrial robots placed in the Industrial Virtual and Augmented Reality Laboratory environment of Tallinn University of Technology and a mobile robot solution developed based on a collaboration between the University of Southern Denmark and a Danish company. Experiments are being performed on the connection between Estonia and Denmark while performing reprogramming tasks of the physical heavy industrial robots. Furthermore, the mobile robot solution is demonstrated in a virtual warehouse environment. Developed methods and environments together with the collected data will enable us to widen the use-cases with non-manufacturing scenarios, i.e., smart city and smart healthcare domains, for the creation of a set of new interfaces and multiplayer experiences.

Towards Implementing a Collaborative Manufacturing Cloud Platform: Experimenting Testbeds Aiming Asset Efficiency

Developing Industrial Internet of Things (IIoT) systems requires addressing challenges that range from acquiring data at the level of the shopfloor, integrated at the edge level and managing it at the cloud level. Managing manufacturing operations at the cloud level arose the opportunity for extending decisions to entities of the supply chain in a collaborative way. Not only it has arisen many challenges due to several interoperability needs; but also in properly defining an effective way to take advantage of the available data, leading to Industrial Digital Thread (IDT) and Asset Efficiency (AE) implementing. This paper discusses implementation concerns for a collaborative manufacturing environment in an IIoT system in order to monitor equipment’s AE. Each concern was addressed in a separate proof of concept testbed. The demonstration is based in a project for the IIoT domain called PRODUTECH-SIF (Solutions for the Industry of the Future).

The Acquisition and Management of Healthcare Data, Within a Hospital Infrastructure

The quality of care provided to citizens by professionals and institutions depends on the quality and availability of information. Early commencement of treatment and medication, and the decisions on how to proceed, depend a lot on patients’ data in the different modalities available. It is also important to notice that large pools of data help inform health and wellbeing parameters for the largest possible community. To make that possible it is necessary both to have the best hospital practices but also to get consent and collaboration from patients. In order to accomplish such a goal, it is necessary to use practices, which adhere to legal constraints and are transparent while handling data and also to transmit those practices and protocols to professionals and patients. The present document aims to provide a framework envisaging the seamless application of the clinical procedures, following legal guidance and making the process known, secure and trustworthy. It aims to contribute to clinical practice, and clinical research, thereby contributing to big data analysis by ensuring trust and best clinical data handling.

Ultrasonic Nondestructive Testing for In-Line Monitoring of Wire-Arc Additive Manufacturing (WAAM)

The applications for metal additive manufacturing (AM) are expanding. Powder-bed, powder-fed, and wire-fed AM are the different kinds of AM technologies based on the feeding material. Wire-Arc AM (WAAM) is a wire-fed technique that has the potential to fabricate large-scale three-dimensional objects. In WAAM, a metallic wire is continuously fed to the deposition location and is melted by an arc-welding power source. As the applications for WAAM expands, the quality assurance of the parts becomes a major concern. Nondestructive testing (NDT) of AM parts is necessary for quality assurance and inspection of these materials. The conventional method of inspection is to perform testing on the finished parts. There are several limitations encountered when using conventional methods of NDT for as-built AM parts due to surface conditions and complex structure. In-situ process monitoring based on the ultrasound technology is proposed for WAAM material inspection during the manufacturing process. Ultrasonic inline monitoring techniques have the advantages of providing valuable information about the process and parts quality. Ultrasonic technique was used to detect the process condition deviations from the normal. A fixture developed by the authors holds an ultrasonic sensor under the build platform and aligned with the center of the base plate. Ultrasonic signals were measured for different process conditions by varying the current and gas flow rate. Features (indicators) from the radio frequency (RF) signal were used to evaluate the difference in signal clusters to identify and classify different build conditions. Results show that the indicator values of the ultrasonic signals in the region of interest (ROI) changes with different process conditions and can be used to classify them.

Investigation of the Effects of Design and Process Parameters on the Mechanical Properties of Biodegradable Bone Scaffolds, Fabricated Using Pneumatic Microextrusion Process

Pneumatic micro-extrusion (PME) is a direct-write additive manufacturing process, which has emerged as a robust, high-resolution method for the fabrication of a broad spectrum of biological tissues and organs. In the PME process, a high-pressure flow is injected into a cartridge, which contains a bioink material, resulting in pressure-driven material deposition on a free surface via a converging conical micro-capillary. In this study, PCL powder was loaded into the cartridge, maintained at 120 °C. The flow pressure was set to 550 kPa. Laminar molten PCL flow was deposited on a glass surface (steadily and uniformly kept at 45 °C), using a 200 μm nozzle. A porous, cylindrical scaffold was designed (honeycomb-filled), having a diameter and height of 10 mm and 3 mm, respectively. To investigate the effects of the design and process parameters, a series of experiments were designed and conducted where print speed was varied at four levels in the range of 0.30–0.45 mm/s with 0.05 mm/s increments. In addition, similarly, layer height and layer width were changed at four levels in the range of 125–200 μm with 25μm increments. Finally, infill density was set at four levels in the range of 0.20–0.35 with 5% increments. As a result, 16 experimental runs were characterized, each replicated four times. Of each of the PME-fabricated samples, an image was acquired (both horizontally and vertically) using a high-resolution CCD camera. Illumination was provided by an LED ring light (being of a brightness in the range of 30,000–40,000 Lux as well as a color temperature of 6000 K). Subsequently, the acquired images were analyzed using in-house digital image processing algorithms, forwarded with the aim to characterize both the diameter and the height of the fabricated bone scaffolds. The veracity of the image-based measurements was corroborated, using offline caliper measurements. Furthermore, the compression properties of the fabricated bone scaffolds were measured using a compression testing machine; the samples were subjected to a compression load, applied with a velocity of 0.08 mm/s. Overall, the results of this study pave the way for future investigation of PME-deposited PCL scaffolds with optimal mechanical and morphological properties for incorporation of hBMSCs toward the treatment of osseous fractures and defects.

Diagram Design of Weaving Process for Touch-Feel Estimation of Plain-Woven Fabrics by Finite Element Method

Digital evaluation of touch-feel in textiles is useful to design fundamental functions of clothing. Here, it is necessary to design textiles for a detailed evaluation of the sensitivity in human’s feelings to consider the life-style creation in various aspects. Then, the objective of this paper is to propose a design method for plain-woven fabrics by touch-feel estimation considering the weaving process with the constitutive relations of yarn. Here, a diagram for control weaving is defined by the diameter of the yarn and displacement quantity of the weaving and the cramping by defining the theoretical thickness. For the effective design to consider various processes, unit-cell of plain-woven structures are fundamentally classified as open set models and closed set models. One of the unit-cell models in the finite element method (FEM) for the plain-woven structure is adopted because the adopted model can consider initial-stress distribution in the weaving process. For touch-feel estimation, an analysis model is constructed by warp, weft, and plungers that cramps the woven structure. A series of diagrams to compress with plungers is shown after constructing a plain-woven structure. As for analyzing the weaving process and the touch-feel estimation in one model, realization of the effective engineering is enabled. This procedure yields that the relationship between the displacement and simulation time suggests for consideration of initial-stress.