Production Of Composite Parts Research Articles

Exploring the curing kinetics of Acrolein-Pentaerythritol resin: Impact of molecular weight and molecular weight distribution on cure behavior

Curing kinetics are crucial for designing and optimizing the process parameters of a resin. This study examines the non-isothermal curing kinetics of acrolein-pentaerythritol (APE) resins, focusing on the impact of molecular weight (MW) and molecular weight distribution (MWD) on their cure behavior. Kinetic parameters were determined using isoconversional and combined kinetic analysis methods through microcalorimeter measurements. The findings suggest that the cure process follows the nucleation and growth models (Avrami−Erofeev equation), with an activation energy of 72.2 kJ/mol. A comparison of two APE resins with different molecular weights and molecular weight distributions reveals that higher MW components expedite the initial curing reaction but impede the main curing process, leading to extended curing durations. This study provides valuable insights into the curing kinetics of APE resin and the influence of MW and MWD, contributing to the reliable and reproducible production of composite parts.

ANN Enhanced Hybrid Force/Position Controller of Robot Manipulators for Fiber Placement

In practice, most industrial robot manipulators use PID (Proportional + Integral + Derivative) controllers, thanks to their simplicity and adequate performance under certain conditions. Normally, this type of controller has a good performance in tasks where the robot moves freely, performing movements without contact with its environment. However, complications arise in applications such as the AFP (Automated Fiber Placement) process, where a high degree of precision and repeatability is required in the control of parameters such as position and compression force for the production of composite parts. The control of these parameters is a major challenge in terms of quality and productivity of the final product, mainly due to the complex geometry of the part and the type of tooling with which the AFP system is equipped. In the last decades, several control system approaches have been proposed in the literature, such as classical, adaptive or sliding mode control theory based methodologies. Nevertheless, such strategies present difficulties to change their dynamics since their design consider only some set of disturbances. This article presents a novel intelligent type control algorithm based on back-propagation neural networks (BP-NNs) combined with classical PID/PI control schemes for force/position control in manipulator robots. The PID/PI controllers are responsible for the main control action, while the BP-NNs contributes with its ability to estimate and compensate online the dynamic variations of the AFP process. It is proven that the proposed control achieves both, stability in the Lyapunov sense for the desired interaction force between the end-effector and the environment, and position trajectory tracking for the robot tip in Cartesian space. The performance and efficiency of the proposed control is evaluated by numerical simulations in MATLAB-Simulink environment, obtaining as results that the errors for the desired force and the tracking of complex trajectories are reduced to a range below 5% in root mean square error (RMSE).

Mechanical recycling of CFRPs based on thermoplastic acrylic resin with the addition of carbon nanotubes

Carbon fibre-reinforced polymers (CFRPs) are commonly used in aviation, automotive and renewable energy markets, which are constantly growing. Increasing the production of composite parts leads to increased waste production and a future increase in end-of-life components. To improve the recyclability of CFRPs, new materials that fit in with the idea of a circular economy should be used as a composite matrix. One such material is a commercially available thermoplastic liquid resin, Elium® (Arkema, France). In this work, the authors investigated how the mechanical recycling process affects the properties of thermoplastic-based carbon fibre composites. CFRPs with neat Elium® resin and resin modified with 0.02 wt.% single-walled carbon nanotubes or 0.02 wt.% multi-walled carbon nanotubes were manufactured using the resin infusion process. Afterwards, prepared laminates were mechanically ground, and a new set of composites was manufactured by thermopressing. The microstructure, mechanical, thermal and electrical properties were investigated for both sets of composites. The results showed that mechanical grinding and thermopressing processes lead to a significant increase in the electrical conductivity of composites. Additionally, a sharp decrease in all mechanical properties was observed.

Environmental Sustainability of vitrimer-based composite materials

Vitrimers are a novel class of polymers known for their dynamic and recyclable properties. They are gaining significant attention as potential alternatives to traditional thermosets in composite manufacturing due to their repairability and reprocessability. This study explores the environmental sustainability of vitrimers in composite materials through a comprehensive Life Cycle Assessment (LCA) approach. The research focuses on vitrimer composite parts production and their recycling process, with a “from cradle to grave approach”.Given the scientific and industrial interest, vitrimer containing disulfide bonds obtained reacting bisphenol A and 4-aminophenyl disulfide (4-AFD or APD) was considered as matrix for the investigated composite part; a traditional epoxy resin matrix composite reinforced with carbon fibers was selected as reference scenario. The recycling process of vitrimer based composites was evaluated, comparing it with conventional thermoset composite recycling method (mechanical recycling). The effects on the environment of these alternatives were evaluated considering different impact categories to provide a comprehensive view of the scenarios.The findings of this study demonstrate that vitrimers can represent a sustainable alternative to traditional thermoset, especially thanks to the possibility of extending the life cycle of a component and recovering continuous filaments from the parts. By shedding light on the potential benefits of vitrimers in reducing the ecological footprint of composite materials, this study contributes valuable insights to sustainable materials development.

Redesigning industrial composite production planning and control for energy awareness

The European Union's requirement for eliminating greenhouse gas emissions from all value chains by 2050 affects most of the manufacturing activities all over the continent. The industrial production of composite parts, favored for new designs throughout the aerospace industry, does not constitute an exemption. For securing global competitiveness, CFRP manufacturers need to adapt to increasing fluctuations in energy supply and prices, induced by a growing share of renewable energy sources. Besides employing more efficient production technologies, decoupling of labor and energy intensive tasks will play a key part. Thereby, energy intensive tasks can be performed while general energy supply is high and demand is low, leading to comparatively lower prices. The perspective of energy supply and price becomes a crucial part in the design of modern production planning and control systems, not only for smokestack businesses, but for small and medium load energy consumers as well. In this contribution, a mathematical representation for modeling industrial scale composite manufacturing is proposed. Beside manufacturing's fundamental production planning and control constraints, CRFP manufacturing's very own peculiarities are outlined and considered as well. It is shown how the virtual mathematical representation of a CFRP manufacturing environment can assist in its energy aware redesign and optimization.

Features of production technologies of composite parts for the railway industry

The present article presents a comparative analysis of the technologies of manufacturing parts made of polymer fibrous composites. For each technology the advantages and disadvantages of its application are given, as well as the types of manufactured products are indicated. Based on these features, conclusions were made about the possibility and effectiveness of the described technologies for the production of composite parts for the railway industry. In addition to the standard, widely used technologies, 3D printing, which refers to the rapidly developing additive technologies, was considered. The comparison of technologies according to the key parameters is given in tabular form.

Modeling, Analysis, and Improvement of Batch-Discrete Manufacturing Systems: A Systems Approach

Production systems include both discrete part and batch operations, where an individual part is manufactured in a discrete operation, and a group of parts are processed simultaneously, i.e., in a batch, on one machine for a batch operation. Many manufacturing industries, such as battery, aircraft, and automotive, consist of mixed batch and discrete part operations, referred to as batch-discrete lines. Although such operations are widely encountered, analytical studies of these systems are limited in current literature. In this paper, a systems approach is presented to model and analyze batch-discrete lines. First, a Bernoulli machine reliability model for a two-machine batch-discrete system is introduced. Using a virtual buffer to represent the batch processing feature, performance evaluation formulae are derived and system properties are investigated. Using them, improvement analyses and bottleneck identification are presented. Then, the model is extended to systems with a quality inspection device under different control policies. To illustrate the applicability of the model, a case study in a composite part production process is described. Such a work delivers a quantitative tool for production engineers and managers to design, analyze, and improve batch-discrete manufacturing systems. <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Note to Practitioners</i> —Many manufacturing systems in aircraft, automotive, battery, medical device, and defense industries include both batch operation and discrete part processing machines. In a batch operation, multiple parts are manufactured simultaneously on a batch machine, while a single part is made in a discrete part machine. Production lines with mixed batch and discrete part operations are named as batch-discrete systems. Analysis and improvement of such systems are critical to ensure high productivity and quality. However, accurate modeling and analysis of batch-discrete systems are lacking in current literature. To bridge this gap, a novel methodology is presented in this paper. Using a Bernoulli reliability machine model with a virtual buffer concept, performance measures are derived for batch-discrete two-machine lines, as well as the reversed discrete-batch lines. Then system properties, such as monotonicity, interchangeability, and reversibility, are investigated, followed by improvement analysis under constraints and bottleneck analysis. By extending to systems with quality inspections, two quality control policies, to scrap either the current batch or the whole inventory after detecting a degraded part, are studied. In addition, a case study of heating (batch) and trimming (discrete) operations in composite panel production lines is presented, and improvement strategies are investigated, to illustrate how to apply the model and analysis in practice.

Human-robot mobile co-manipulation of flexible objects by fusing wrench and skeleton tracking data

ABSTRACT Over the past decades, robots have been extensively deployed in multiple industries. More recently, industrial robots have been taken out of their cages, being more present in dynamic environments, interacting in the close vicinity of human operators. Traditionally, robots have been mainly developed to perform pre-programmed tasks. However, some tasks are too complex or expensive to be performed by a robotic system alone. Examples are the handling of large sheet-like objects in the composite part production or plastic film wrapping industry. This work presents a hybrid wrench and vision reactive control approach towards the handling of large (non-)rigid materials. The presented approach fuses force-torque data and skeleton tracking to control a mobile manipulator in an intuitive manner, by using the intelligence of the operator as much as possible. Using this approach, tools such as path planning, or object modelling are not essential to obtain the results. The hybrid controller is subject to stability experiments where the controller responses are monitored when the mobile manipulator is subject to a step and sinusoidal function as input. Lastly, the overall approach is illustrated with a proof-of-concept task in which a flexible sheet is handled by a mobile manipulator and human operator together.

COMPUTATIONAL JUSTIFICATION OF THE USE OF COMPOSITE METAL-METAL POLYMER PARTS IN THE PRODUCTION OF FUNCTIONAL STRUCTURES

Additive manufacturing of metal parts occupies an increasing number of areas of mechanical engineering, but still remains too expensive for mass use. Based on the experience in the production of combined metal-metal polymer forming parts of molds, a new method for the production of composite parts from a metal shell filled with metal polymer is proposed. The strength calculations by the finite element method of the exoskeleton part and a sample of simplified geometry are given as the basis of the study. A comparison of the strength characteristics of parts made of various materials and their combinations showed high strength characteristics of a composite part made of a metal shell and a metal polymer filler. The metal-metal polymer composite part is distinguished not only by its high strength, but also by a significantly lower cost due to the reduction in the volume of 3D printing with metal. The article substantiates the main problems facing researchers and technologists in the development of a practically applicable technology for producing such composite parts.

Justification of the Use of Composite Metal-Metal-Polymer Parts for Functional Structures.

The additive manufacturing of metal parts takes up an increasing number of areas of mechanical engineering, but it still remains too expensive for mass use. Based on the experience in the production of combined metal-metal-polymer forming parts of molds, a new method for the production of composite parts from a metal shell filled with metal-polymer is proposed. As a basis for the study, strength calculations are given by the finite element method for the details of the exoskeleton and a sample of simplified geometry. Comparison of the strength characteristics of parts made of various materials and their combinations showed high strength characteristics of a composite part made of a metal shell and a metal-polymer filler. The metal-metal polymer composite part is distinguished not only by its high strength but also by a significantly lower cost, due to the reduction in the volume of 3D printing with metal. The problems of obtaining composite structures are also discussed. The main problem is the development of a metal-polymer casting technology. The process of filling a thin-walled shell with a metal-polymer causes difficulty.

Machine Vision for As-Built Modeling of Complex Draped Composite Structures.

The transition in the use of fiber composite structures from special applications to application in the mass market is accompanied by high demands in quality assurance. The consequential costs of unclear process design, unknown fiber orientations, and uncertainty regarding the effects of any fiber angle deviations can lead to market considerations (higher costs/time for development) in mass production that advise against the use of fiber composites, despite their superiority compared with conservative materials. Active monitoring of the deposited reinforcement layers and an evaluation of the real fiber orientation can form the basis of a robust industrial use of fiber composites by a first-time right production that is able to reduce the process variability. This paper describes the application of an image analysis system to provide both geometric topology and local reinforcement fiber orientation feedback to a finite-element (FE) model. The application during an industrial composite part production is described, and the possibilities of using it for the improvement of the lightweight character, the reduction of rejects, and the realization of a quality management system are shown. The determined component data are made directly available for use in numerical simulations and, thus, they serve as a non-destructive evaluation of the components under real conditions in which all production-dependent influences that affect the fiber orientation are incorporated.

Additive Manufacturing Processing of Plastics for Mass Production of Composites Tooling: Technical and Economic Analysis

AbstractThe present paper focuses on the use of several additive manufacturing (AM) techniques for tooling manufacturing for composite parts production. A geometry that prevents mandrel removal is selected and it is analyzed in a real industrial environment for composites production using autoclave molding. The use of two different AM mandrels is evaluated: fused deposition modeling and liquid crystal display. The results are analyzed in terms of composites part quality, processing time and final part cost.

Towards robust human-robot mobile co-manipulation for tasks involving the handling of non-rigid materials using sensor-fused force-torque, and skeleton tracking data

Over the past decades, robots have been extensively deployed in multiple industries. More recently, industrial robots have been taken out of their cages, being more present in dynamic, uncertain environments interacting in the vicinity of humans. Traditionally, robots have been mainly developed to perform pre-programmed tasks. However, some tasks are too complex or expensive to be performed by a robotic system alone. One of these hard tasks is the handling of large fibre sheets in composite part production. This paper presents a force-based approach towards human-robot co-manipulation of tasks involving the handling of non-rigid materials, such as composite fibres. Our approach fuses the data of a force-torque sensor and skeleton tracking data from a 2D camera to control the mobile manipulator in an intuitive manner, by using the intelligence of the operator as much as possible. By using this approach, tools such as path planning, high-level task planning, or modelling of objects to be manipulated are not essential to obtain the results. The overall approach is illustrated with a co-manipulation proof-of-concept experiment in which a mobile manipulator robot handles a flexible textile sheet together with a human operator.

Investigation of functional core-rim composite part production by inserted powder injection moulding

In this study, the use of Cu and Ni interlayers have been investigated for functional core-rim composite part production with WC-Co 9 wt-% feedstock/steel. For this purpose, different experiments have been performed and joining condition, shear strength and microstructure of the intermediate region have been examined. It has been found that AISI 4340 insert/WC-Co have been joined and 85.8 MPa shear strength achieved, but high speed steel insert has not joined. Moreover, it has been determined that better results are obtained with Ni interlayer. Under the same conditions, when the 40 µm Ni interlayer has been used between AISI 4340 core and WC-Co rim, shear strength has been increased approximately twice and has been 162.7 MPa.

Monitoring of the vacuum infusion process by integrated RFID transponder

To ensure the competitiveness of Germany in the manufacturing of composite parts, greater resource efficiency and higher standards of quality are needed. The process of vacuum infusion is used by many companies to produce a great variety of composite parts for markets like shipbuilding, wind energy and many more. Often, those parts have a complex structure requiring a great amount of skill and experience to produce at a high quality. Therefore, the development process often requires several experimental trials before sufficient quality is reached, using up material and time. By using RFID (radio frequency identification) transponders as sensors, the manufacturing process can be monitored, and less reject is produced. When using RFID transponders as sensors, they can then be used to track the component through further assembly steps and as a storage device during the lifetime of the finished product, enabling a simultaneous way of protecting against product piracy and structural health monitoring.The correlation between the RFID signal and the resin state in the fiber layup is shown for several systems. The results show that RFID transponders can be used for both glass and carbon fiber parts to monitor the production process. This will allow a more efficient production of composite parts, shortening process duration and saving resources. The monitoring of the resin flow and cure in the fiber layers underneath an RFID transponder allows the manufacturer to gain information about the state of the process during production. Resin profiles in a thick fiber layup were successfully tracked using an RFID transponder placed above them. The monitoring of the resin in the fiber layers allows the manufacturer to gain information about the state of the process during production.Summarizing the results of our research, the use of RFID transponders as sensors allows an efficient and process friendly monitoring of the resin behavior during vacuum infusion, and the transponders can be further used in logistics. The tracking of the resin behavior beneath a sensor opens up possibilities for further optimization of the part quality.

Analysis of applicability of polymer, composite materials as components of aeronautical structures

The paper considers the problems of using composite materials to create power units of modern passenger planes. It gives examples of crash situations involving planes of the leading companies, describes some technological aspects in the production of composite parts.

Three-dimensional numerical simulation for resin transfer molding of automotive wheel

Resin transfer molding (RTM) is a manufacturing process that uses liquid resin to saturate a fiber preform placed in a closed mold cavity. For robust fabrication of the composite, fiber preform needs to be completely impregnated with polymer resin during mold filling. Hence, the understanding of resin flow and void formation in RTM is very important to design the mold and processing conditions for successful production of composite parts. In this study, three-dimensional (3D) numerical simulation was carried out to investigate the resin flow behavior in a complicated mold. An automotive wheel rim was designed and fabricated using carbon fiber preform and epoxy resin. Case studies were performed to minimize the void formation during processing.

Large quantity composite part production makes further progress

Injection molding machine manufacturers are looking to bring their expertise of large quantity part production to the composite industry.

Method for in situ analysis of volatiles generated during cure of composites

Conventional epoxies used in composites are formulated to release minimal amounts of volatiles during cure, aside from moisture, which is a perpetual concern. However, a variety of polymers are used in production of composite parts, including adhesives, prepregs, and non-epoxy polymers, and sources of volatilization during processing can be both difficult to determine and problematic. Here we demonstrate a general method for in situ analysis of volatile release during cure. The method improves upon traditional characterization techniques of TGA/MS and TGA/FTIR (thermogravimetric analysis, mass spectroscopy, and Fourier transform infra-red spectroscopy). We characterize a commercial epoxy prepreg typical of those used in aerospace, a benzoxazine/epoxy blended liquid resin intended for high-temperature service, and finally, a high-temperature polyimide. By understanding the identity, origin, and kinetics of volatile release in these three materials, we can prescribe additional pre-treatments and define process windows to minimize and even eliminate volatile-induced porosity. Finally, we demonstrate the utility of the reaction cell/FTIR approach for characterizing cure-induced volatiles and mitigating final part porosity.

Effect of fabric architecture, compaction and permeability on through thickness thermoplastic melt impregnation

To reduce the cycle time of structural, automotive thermoplastic composites, we investigated the potential of direct thermoplastic melt impregnation of glass fabrics using an injection moulding process. At the high pressures that occur during the process, the effect of the fabric architecture on the impregnation, compaction, volume fraction and permeability of two unidirectional fabrics was studied. Using impregnation experiments with a low viscosity PA6 melt, we identified a favourable processing window resulting in an impregnation time of 5 min. The impregnation experiments with thermoplastic melts demonstrate that textile architectures promoting dual scale flow during impregnation are favourable for complete filling. Based on our findings, thermoplastic compression resin transfer moulding is an efficient processing route for automated production of composite parts with a high fibre volume fraction, if the fabric architecture is adapted for higher processing pressures and by fully utilising dual scale flow.