Plastic Parts Research Articles

High-Throughput in Situ Characterization of Polymer Crystallization under an Intense Flow, High Pressure, and Cooling Gradient during Injection Molding

Injection molding is a polymer-processing method widely used, which consumes about one-third of global plastics and produces 80% of plastic parts. However, it is still challenging to in situ reveal the structural evolution of polymers during injection molding, which is a long-standing obstacle to understand the relationship of processing–structure–property. This work has first built an in situ investigation system with the aid of a highly brilliant synchrotron X-ray and large experimental space with a length of 30 m, width of 8 m, and height of 6 m, allowing the installation of an industrial-scale injection molding machine. Based on the characterization system, the fast millisecond-resolved structural evolution of general semicrystalline polymers is identified. Various structural types of information including crystallization kinetics, polymorphism, and the growth and orientation of their lamellar crystals under an actual environment of non-isothermal crystallization with a cooling gradient, intense flow, and high pressure during injection molding have been revealed for the first time. The high-throughput feature of the system provides a vital prerequisite for the subsequent establishment of a quantitative database of processing parameter–structure–performance and the precise regulation of polymer aggregation structures, which is valuable for the digitalization and intelligence of the development of the injection molding industry and integration into the Industrial Internet.

INJECTION MOLDING OF POLYCARBONATE THICK-WALLED PARTS USING A TOOL WITH VARIOUSLY DESIGNED GATE INSERTS

Injection molding is an advantageous technology for the mass production of plastic parts without the necessity for additional procedures. The applicability of this method is still partially limited by the required properties of the manufactured parts. Especially in the field of optics, there is a need to produce thick-walled parts while maintaining their transparency. This paper reports on how various shapes of gating systems affected the process parameters and cavity filling during the injection molding of polycarbonate thick-walled specimens. These outcomes demonstrated that film gates and their alternatives are more suitable for the standard injection molding of thick-walled optical products than the triple-edge gating systems. Favorable results were observed particularly in the uniformity of cavity filling, size of shrinkage, and in the occurrence of defects such as voids or sink marks.

Multiplanar continuous fiber reinforcement in additively manufactured parts via co-part assembly

PurposeMany additively manufactured parts suffer from reduced interlayer strength. This anisotropy is necessarily tied to the orientation during manufacture. When individual features on a part have conflicting optimal orientations, the part is unavoidably compromised. This paper aims to demonstrate a strategy in which conflicting features can be functionally separated into “co-parts” which are individually aligned in an optimal orientation, selectively reinforced with continuous fiber, printed simultaneously and, finally, assembled into a composite part with substantially improved performance.Design/methodology/approachSeveral candidate parts were selected for co-part decomposition. They were printed as standard fused filament fabrication plastic parts, parts reinforced with continuous fiber in one plane and co-part assemblies both with and without continuous fiber reinforcement (CFR). All parts were loaded until failure. Additionally, parts representative of common suboptimally oriented features (“unit tests”) were similarly printed and tested.FindingsCFR delivered substantial improvement over unreinforced plastic-only parts in both standard parts and co-part assemblies, as expected. Reinforced parts held up to 2.5x the ultimate load of equivalent plastic-only parts. The co-part strategy delivered even greater improvement, particularly when also reinforced with continuous fiber. Plastic-only co-part assemblies held up to 3.2x the ultimate load of equivalent plastic only parts. Continuous fiber reinforced co-part assemblies held up to 6.4x the ultimate load of equivalent plastic-only parts. Additionally, the thought process behind general co-part design is explored and a vision of simulation-driven automated co-part implementation is discussed.Originality/valueThis technique is a novel way to overcome one of the most common challenges preventing the functional use of additively manufactured parts. It delivers compelling performance with continuous carbon fiber reinforcement in 3D printed parts. Further study could extend the technique to any anisotropic manufacturing method, additive or otherwise.

Optimization of the Injection Mold Runner System of the Transport Means Plastic Parts

This paper describes the optimization of dimensions of the individual injection mold runner system of the plastic part used as the frame for various devices in transport means. Nowadays, the great emphasis is placed on the production time and finances associated with design and production. As a result, simulations are being employed increasingly. This paper aims to describe the design the optimum size and shape of the sprues and runners required for proper filling and to simulate the injection molding process to avoid problems and defects that tend to be caused by an incorrectly sized runner system. As a result, some adjustments were made to the size of the runner system to eliminate problems with underfilling, overfilling, air traps and weld lines. The difficulties with the original design were fixed by the optimized solution, which improved the monitored parameters. Additionally, the technological parameters of the injection process were modified, resulting in lower stress on the injection mold in the injection process.

Research on warping optimization of automobile mesh based on artificial intelligence algorithm

Automobile mesh is a typical large plastic part prone to warping deformation in the manufacturing process, which seriously affects the quality of products. The traditional method is to find the optimal combination parameters to reduce warping deformation in the forming process through repeated trial or mold flow analysis with high cost. In this study, An optimization method based on an artificial intelligence algorithm is proposed to optimize the warping deformation of the automobile mesh. In the optimization method, artificial intelligence regression algorithm-support vector machine regression was used to establish the nonlinear function relationship (prediction function) between the molding process parameters and the warpage of automobile mesh, and the performance of the prediction function was optimized by a genetic algorithm. The optimized prediction function was taken as the fitness function, the warping value was regarded as the fitness value, and genetic algorithm is used again to obtain a set of optimal process parameters and minimum warpage values. Finally, the reliability of the optimization method is verified by the modal flow analysis software.

Research on roughness prediction model of robotic sanding carbon fiber reinforced plastics

By taking a pneumatic eccentric grinder and round sandpapers as research objects, the modeling method is proposed to accurately predict the surface roughness of robotic sanding carbon fiber reinforced plastic parts. A four-factor, the four-level orthogonal experiment was conducted which took four process parameters into account: pressing force, feeding speed, grit size, and supply air pressure. The multiple linear regression analysis method was then applied to create a roughness prediction model. Furthermore, accuracy validation results show that the model’s prediction error is within ±9%.

ANALYSIS OF MACHINING PROCESS IN INJECTION MOULDING USING PLC AND PROCESS PARAMETERS

Injection moulding is most advanced manufacturing technique for the manufacture of plastic parts with high accuracy, complexity and speed is injection moulding. A plastic pallet is heated by a heating element, then a mould cavity is filled with molten metal using a high-pressure injection technique with the help of a screw, and the final component is formed when the plastic has cooled and solidified. The injection moulding process is incredibly flexible and may be used to produce components with intricate geometries and precise tolerances. The layout of moulds, material demand and processing parameters are only a few of the complex factors that move in the complex way of injection moulding. Using PLC we can easily automate the process. In addition to how to improve process parameters and its solution to work efficiently. Industrial automation has become essential. The programmable logic controller (PLC) is a programming system used for automation. It is a user-friendly, specially designed computer with microprocessors that performs various types and complexity of control tasks. The aim is to monitor key process variables and modify operations as needed. PLC is used to automate manufacturing and assembly in the industrial context. The study focuses on the automation of injection moulding machines using PLCs and pneumatic cylinders. There are four cylinders, each representing different tasks. The four steps of this process include the clamping and dissolving of the die, the opening and closing of the die. The injection of plastic materials while they are still melted, and finally the ejection of the components.

Design and Fabrication of Imprint Machine

Abstract: This Research Paper aimed at automating the process of marking serial numbers or identification codes on metal, wood, plastic components. This Machine accurately punch numbers onto metal, wood, plastic parts with varying sizes and thicknesses. The machine's design includes a robust frame, a pneumatic system, and a control system that allows for precise control of the number punching process. The punching mechanism consists of a series of hardened steel punches that can be easily replaced and adjusted to accommodate different numbers and character sizes. The control system allows operators to input the desired serial number or identification code, control the punching force, and regulate the individual spacing. The machine also includes safety to prevent injury to operators and damage to the metal parts. Overall, the design and fabrication of a imprint machine for metal parts will provide an innovative solution for manufacturers looking to streamline their product identification process.

Predicting and Controlling the Quality of Injection Molding Properties for Fiber-Reinforced Composites

<div>Fiber-reinforced composites are widely used in injection molding processes because of their high strength and high elastic modulus. However, the addition of reinforcing agents such as glass fibers has a significant impact on their injection molding quality. The difference in shrinkage and hardness between the plastic and the reinforcement will bring about warpage and deformation in the injection molding of the product. At the same time, the glass fibers will be oriented in the flow direction during the injection molding process. This will enhance the mechanical properties in the flow direction and increase the shrinkage in the vertical direction, reducing the molding quality of the product. In this study, a test program was developed based on the Box-Behnken test design in the Design-Expert software, using a plastic part as an example. Moldflow software was used for simulation, and data analysis of the experimental data was carried out to investigate the significance of the influence of each injection molding process parameter on the molding quality. In addition to this, a mathematical model between the injection molding process parameters and the quality objectives was established by optimizing the model parameters of the back-propagation (BP) neural network through the ant colony optimization (ACO) algorithm. The established mathematical model is then globally optimized using a multi-objective function optimization based on the non-dominated rank-based sorting genetic algorithm (NSGA-II) to obtain the optimal combination of process parameters. The research in this article provides a theoretical basis for further combining intelligent algorithms to improve injection molding quality.</div>

A physics-informed deep neural network for surrogate modeling in classical elasto-plasticity

In this work, we present a deep neural network architecture that can efficiently surrogate classical elasto-plastic constitutive relations. The network is enriched with crucial physics aspects of classical elasto-plasticity, including additive decomposition of strains into elastic and plastic parts, and nonlinear incremental elasticity. This leads to a Physics-Informed Neural Network (PINN) surrogate model named here as Elasto-Plastic Neural Network (EPNN). Detailed analyses show that embedding these physics into the architecture of the neural network facilitates a more efficient training of the network with less training data, while also enhancing the extrapolation capability for loading regimes outside the training data. The architecture of EPNN is model and material-independent; it can be adapted to a wide range of elasto-plastic material types, including geomaterials; and experimental data can potentially be directly used in training the network. To demonstrate the robustness of the proposed architecture, we adapt its general framework to the elasto-plastic behavior of sands. We use synthetic data generated from material point simulations based on a relatively advanced dilatancy-based constitutive model for granular materials to train the neural network. The superiority of EPNN over regular neural network architectures is demonstrated through predicting unseen strain-controlled loading paths for sands with different initial densities.

A nonlinear constitutive model for whole stress–strain behaviors of compressed rocks incorporating crack closure effect

AbstractThis paper is devoted to establishing a nonlinear constitutive model incorporating crack closure effect for capturing the whole process of rock deformation and failure behavior under compression. The model formulated in the framework of irreversible thermodynamics is based on the additive decomposition of the total strain into crack closure strain, elastic, and plastic parts. New specific criteria are proposed for the description of crack closure strain and plastic strain evolution. Notably, analytical solutions of the model under conventional triaxial compression loading conditions are derived. For application, a robust semi‐implicit return mapping (SRM) algorithm with a crack closure strain correction and a plastic strain correction is developed. The analytical solutions, herein, are subtly used to calibrate model parameters and as reference results for assessing the accuracy and robustness of the SRM algorithm. Validation of the model conducted by comparing with experimental data from the literature shows that the model can properly describe the nonlinear mechanical behaviors of rocks, including crack closure effect, strain hardening/softening, peak and residual strength, as well as volumetric compaction/dilation transition. In addition, a nonlocal formulation is introduced as an extension of the model to remedy the mesh dependency problem.

A new laser welding method of two transparent plastic parts based on reflector assisted method

It is a challenging work to joint two transparent plastic parts using traditional laser welding because the absorptivity of transparent plastic on short wavelength (800–1000 nm) laser energy is very low. During the laser welding of two transparent plastic parts, although laser absorber and long wavelength (1600–2000 nm) laser can obtain the high-strength weld joint, the problems of unattractive weld joint or pollution will occur when laser absorber is used, and the laser energy utilization coefficient is about 70% when long wavelength laser energy is used. To address this issue, this paper proposes a new production method for the absorber-free laser welding of two transparent plastic parts based on reflector assisted method. From three-dimensional thermal model, it can be found that the simulation data of the modified Gauss cylindrical body heat source show better agreement with the experimental result than those of Gauss surface heat source and Rotary-Gauss body heat source. In addition, for the same the weld joint width on the contact surface, the reflector assisted laser welding method can decrease the laser energy consumption by about 20%. Moreover, the maximum shear force of weld joint can be up to 1315 N. Under the same process parameters, the reflector assisted method can increase the shear strength of weld joint by 15.3%. Hence, the reflector assisted method has good application and promotion value in laser welding two transparent plastic parts.

RESEARCH ON THE TECHNOLOGY OF PREPARING PLASTIC AND THREADED COMPONENTS USING 3D PRINTING OR ADDITIVE MANUFACTURING

Threaded components play a crucial role in ensuring the safety and reliability of systems by joining components together. Proper selection of thread type and size, ensuring proper machining and storage of components, and addressing potential issues such as leakage, vibration, and misalignment all play a special role. It is known that there is a big difference in the nature of the destruction of metal and plastic threaded connections, in particular, when the nut is made of plastics, and the bolt is made of steel, or vice versa. In this regard, at present there is no consensus in assessing the strength of plastic threaded connections. On the one hand, it is recognized that, due to a more uniform distribution of the load, plastic threaded connections have a significant load capacity. Numerous examples of the use of plastic threaded connections in pressure pipelines, in large plastic parts subjected to dynamic loads, various loaded fasteners - all these examples confirm that plastic threaded connections can withstand very high loads. Production of a thread of plastic details is rather difficult, than on metals. It is connected with the physical-mechanical processes coming in the course of production of concrete thread details from plastic by method of pressing and casting under pressure. Also mechanics of formation of plastic threads on details of the oil-field equipment on the specific properties differ from the threads received by a machining method on metals. As thread surfaces on plastic details are formed in compression molds depending on materials and the modes: temperatures, pressure and time of production. These regime parameters and guided parameters play a part at a guaranty of physicalmechanical properties of details in the course of production. The use of plastic or polymer threads in the oil and gas industry is increasing due to their unique characteristics and advantages over traditional metal threads. Recently, 3D printing (additive manufacturing) has become more widely used for the preparation of plastic threads. The article will discuss the methods and characteristics of preparing plastic threaded components, as well as their advantages and certain incompatibilities. Keywords: threaded components, plastic threaded components, preparation methods, 3D and 4D printing.

Wetting Characteristics of Laser-Ablated Hierarchical Textures Replicated by Micro Injection Molding

Texturing can be used to functionalize the surface of plastic parts and, in particular, to modify the interaction with fluids. Wetting functionalization can be used for microfluidics, medical devices, scaffolds, and more. In this research, hierarchical textures were generated on steel mold inserts using femtosecond laser ablation to transfer on plastic parts surface via injection molding. Different textures were designed to study the effects of various hierarchical geometries on the wetting behavior. The textures are designed to create wetting functionalization while avoiding high aspect ratio features, which are complex to replicate and difficult to manufacture at scale. Nano-scale ripples were generated over the micro-scale texture by creating laser-induced periodic surface structures. The textured molds were then replicated by micro-injection molding using polypropylene and poly(methyl methacrylate). The static wetting behavior was investigated on steel inserts and molded parts and compared to the theoretical values obtained from the Cassie–Baxter and Wenzel models. The experimental results showed correlations between texture design, injection molding replication, and wetting properties. The wetting behavior on the polypropylene parts followed the Cassie–Baxter model, while for PMMA, a composite wetting state of Cassie–Baxter and Wenzel was observed.

Development of sustainable 3D printing filaments using recycled/virgin ABS blends: Processing and characterization

AbstractWaste plastic exposed to the environment creates problems and is of significant concern for all life forms. To reuse the waste plastic in a well‐organized manner and make it more productive, extrusion‐based additive manufacturing, specially fused deposition modeling technique, can be an effective way. Hence, the primary objective of this work is to reuse ABS waste for developing sustainable three‐dimensional printing filaments. A mixed feedstock processing approach is used to develop filaments, in which recycled ABS is blended with virgin ABS in weight ratio of 10%–50%. The rheological and thermo‐mechanical properties of the extruded filaments were examined. Results indicated that increasing extrusion temperature from 190°C to 195°C produced significant physical changes in ABS blends. There is a breakdown of styrene acrylonitrile and butadiene component in ABS which causes strain hardening and material stiffening. The Young's modulus, yield strength and ultimate tensile strength of 80% RABS/20% VABS filament were found to be 2329, 34.814 and 40.82 MPa, respectively, which is close to VABS filament. The novel filament produced from recycled/virgin ABS blends has the capability to replace commercially available ABS filaments for fabricating high‐quality plastic parts through an additive manufacturing routine.

A Machine Learning Approach for Automated Cost Estimation of Plastic Injection Molding Parts

Market competition leads to shorter cycle times for new or updated products. Therefore, flexibility in reacting to market changes, product development, and all related processes must be accelerated. In this regard, accurate cost estimation in the early stages of product development is critical for assessing the economic viability of a product. However, cost estimation requires data and expertise from several departments. Machine learning approaches could improve the accuracy and reduce the time needed for cost estimation. To investigate the eligibility of machine learning based cost estimation, a case study was conducted on an industrial company that produces plastic molding parts as key components of its products. The study involved training various supervised machine learning algorithms on a dataset of plastic injection molding parts using three different cost calculation methods. The three methods differed in the extent to which they considered the different process steps involved in the production of the parts. Different tree-based machine learning regression models and neural network models were trained to identify the most suitable approach for cost estimation in the given context. The results showed that tree-based machine learning algorithms outperformed neural networks and that individually predicting manufacturing parameters for cost calculation of each manufacturing process step leads to the most accurate cost estimation. This paper demonstrates how machine learning can support cost estimation in the early stages of the product lifecycle, reducing development times and improving cost estimation accuracy.

On-board and port 3D printing to promote a maritime plastic circular economy

Oceanic plastic pollution has become one of the most serious problems in terms of the environment, and Circular Economy (CE) strategies are being implemented to reduce it. The article presents the results of a diagnosis of plastic waste in the maritime sector and the use of 3D printing as an enabling technology of CE around plastic. Maritime industries were asked about their plastic waste generation and potential parts and components which could be replaced by equivalent parts made by 3D printing. To close the CE loop, these parts would be printed with filament from the maritime industries’ plastic waste. The article addresses this process of generating filament that enables the CE and how this printing process can be affected and corrected under on-board conditions. A polypropylene-based strapping tape waste was chosen to produce recycled filament. This filament resulted stiffer than the commercial filament and, through an additivation process, it achieved better flexural properties. Finally, the 3D printing process during on-board unstable conditions was improved by an automatic and electronic correction on the 3D printer machine itself.

Understanding the multilevel phenomena that enables inorganic atomic layer deposition to provide barrier coatings for highly-porous 3-D printed plastic in vacuums

The potential of 3-D printing polymers to achieve low-weight space flight hardware has seen increasing interest. Additionally, robust 3-D printed polymer vacuum equipment would provide highly attractive low-cost alternatives to conventional industrial-scale tools for the scientific community. Inorganic barrier coatings of plastic parts can be used to minimize outgassing and damage to polymers from extreme vacuum environments. Among different coating technologies in this area of research, atomic layer deposition (ALD) has shown the most promise. Nevertheless, the exact formation morphology of ALD coatings on 3-D printed polymers under vacuum are not yet well understood, which hinders use of 3-D printed polymers in vacuum environments. In this study, the film formation mechanisms of ALD alumina on porous 3-D printed polymers are investigated via SEM, EDS, XRD, ATR-FTIR, and XPS. ALD alumina is deposited on 3-D printed pigmented and un-pigmented acrylonitrile butadiene styrene, polycarbonate, commercially available polypropylene, and pure polypropylene. The results reveal that the formation of the ALD barrier layer, its thickness, and diffusion of ALD precursor materials into the polymer substrate is a multi-scale phenomenon, and that substrate porosity and polymer functionality both dominate film formation behavior. Additionally, this study demonstrates that during ALD processes on 3-D printed polymers a vapor phase infiltration (VPI) growth mode also occurs, especially where porosity is present.

White paper: Delta Tecnic argues that the masterbatch is key to ensuring a consistent color

Color uniformity is a fundamental concern for the plastic parts manufacturing industry. Delta Tecnic is a company specializing in the manufacture of masterbatch for the PVC and Cable industry. Of course it aims to ensure that the color of the manufactured parts is consistent throughout their useful life and also between productions of the same product.

Experimental Analysis on Polypropylene Moulded Part for Performance of Laser Printing

Now a day plastic injection molding is widely used process to manufacture engineering product and consumer goods typically thermoplastic is combined with rubber or another thermoplastic like RM master batch is used to add color to the Molded part also the laser marking on plastic part and their printing cut, faint issue observed. The aim of the study was to Optimize the injection parameters and processing condition for the laser performance on polypropylene part. To achieve enhanced dark laser marking on polypropylene, the process parameter of plastic injection molding and the Raw material master batch mixing parameter successfully prepared this laser–sensitive composite consisted of a high Laser induced carbonization rate.in plastic injection molding use of raw material and mixing of master batch is considerable factor for faint laser marking. Because of laser does not respond well on carbonization added material, it was evident that master batch having the carbon properties is much more responsible for faint laser marking issue on polypropylene material part. The effect of laser beam interaction (Nd: YVO4) with selected operational parameters on the Quality of graphical features obtained on the surface of polypropylene-molded pieces with different surface Textures (variable parameters of the surface layer). Polypropylene test specimens were injection molded using original injection molds Products with variable end parameters determined by the position of the cavity circle can be identified. The layout of the laser function, the beneficiary texture of the molded piece, the molded color and the support of the marking piece allow the evaluation of the graphic symbol performance by means of laser marking of the type of master back in their rendering relationship. Marked evaluation criteria were adopted for the project.