Hot Moulding Research Articles

Thermal stability and anti-ablation performance of plasma spray coated-YSZ on Al2TiO5 modified novel ablative carbon-phenolic composites

Abstract Despite ongoing challenges, ablative thermal protection systems are among the most promising methods for safeguarding spacecraft during re-entry thermal protection systems (TPS). A novel aluminium titanate (Al2TiO5/AT) and a highly efficient thermal barrier of coating (TB/TBCs) made from yttria-stabilized zirconia (YSZ), powder, but deposited using the plasma spray technique on polyacrylonitrile (PAN)-based carbon fiber fabric(C)-reinforced with resorcinol phenol formaldehyde resin (RF) composites (C-RF)) would be a potential candidate for TPS applications. This study investigates the composites with varying wt.% of AT that were developed, namely 0 wt.% (YSZ-C-RF), 1 wt.%, 3 wt.%, and 5 wt.% (YSZ-AT-C-RF) by utilizing a hot press moulding machine. Thermal stability and ablation performance of unmodified C-RF with modified YSZ-C-RF and YSZ-AT-C-RF composites are examined through thermogravimetric analysis (TGA) and oxyacetylene torch test/OAT (4.0 MW/m2 for 60 sec). Also, the phase composition and microstructure of the ablated surface are determined by X-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques. The TBC of YSZ has an obvious influence on the residual weight ratios at high temperatures in C-RF and also plays a positive role in increasing thermal stability under nitrogen atmosphere for enhancing ablation resistance concerning YSZ-C-RF. The mass and linear ablation rates (MAR and LAR) of the composites after modifying the surface by YSZ-coated particles are reduced by 82.98% and 15.65%, respectively. Similarly, the introduction of AT particles and TBC of YSZ results in evidence of improving the thermal stability and the ablation resistance in varying wt.% of YSZ-AT-C-RF composites. The primary optimum AT weight loading for enhancing ablation resistance in YSZ-C-RF composites is 1wt.%. The modification of 1wt.% AT particles and YSZ-Coated particles reduce MAR and LAR by 54.79% and 61.94%, respectively. This work offers a meaningful method to remarkably enhance the ablation performance of the modified C-RF and YSZ-AT-C-RF composites.

Transverse energy absorption performance of sandwich tubes with various origami foldcores

Nowadays, composite sandwich tubes are extensively utilized in the civil and aerospace industries due to their superior strength-to-weight mechanical properties. Origami-based core offers a large enhancement of the mechanical properties, yet little study research focuses on the effect of various foldcore configurations on the transverse mechanical properties of sandwich tubes, necessitating the design method for applications. This study introduces an innovative approach by incorporating origami into the composite sandwich core to enhance the transverse energy absorption capacity. The quasi-static transverse mechanical properties of carbon fibre-reinforced polymer (CFRP) sandwich tubes with foldcores are studied under three-point bending-like local compression and transverse structural compression. A systematic geometric design framework and numerical modelling technique are provided. By integrating finite element analysis and experiments, the research investigates the effects of various origami foldcore configurations and geometric parameters on transverse energy absorption capacity. The experiment setup is provided by sandwich tubular specimens with a full-diamond configuration as the foldcore. The cylindrical tubes (foldcore) of the sandwich structures were manufactured using four plies [0°]4 of T700 (T300) woven CFRP with the hot press moulding (vacuum bag using female and male moulds) technique respectively. Then, the parametric study and damage mode analysis of eight different foldcore patterns (axial Miura, circumferential Miura, diamond, Kresling, and their curved-creased counterparts) were studied. The results showed the superior energy absorption performance of the sandwich tube with Miura-pattern foldcore over the origami-pattern counterparts, nested tube, and traditional honeycomb sandwich tube with CFRP or aluminium-made cores. Therefore, the structural parameters optimisation of the Miura pattern tube was carried out by the Response Surface method (RSM) and a design strategy for increasing the energy absorption capacity was found. The findings offer guidance for designing high-specific energy absorption tubular structures for future advanced engineering applications.

Target energy management for sustainable molding companies: Consumption, saving, and enviro-economic investigation

The industrial sector is the world's leading energy consumer and CO2 emitter and yet has not received sufficient focus to reduce its energy consumption and adverse environmental impact. So, this paper addresses this gap by presenting industrial-based research on energy audit and target energy management for a sustainable bulk molding company in Alexandria, Egypt. The management focuses on the hot press hydraulic building section which consumes more than 30 % of the company's total energy. The sources of energy losses within this section are identified and quantified. Energy-saving measures including thermal energy management are proposed, implemented and valorized based on energy savings, cost and environmental impact. The yearly savings on energy consumption, energy bills and CO2 emission reduction for the molding machines are estimated. The results show that the main sources of molds' energy losses are in the preheat stage and convection and radiation from the hot mold surfaces. The maximum energy saving due to modifying the preheat stage duration is about 51 %. The gained energy reduction due to changing the mold insulation boards is about 17.5 % and 55.3 % during the preheat and production stages, respectively. Moreover, using double layer insulation boards with the mold insulation cage reduces energy consumption by about 69.5 %. The payback period falls between 1.53 and 6.11 months where these techniques for one machine can save 1229.3 $/year and reduce 16,651.598 kg/year CO2 emission. The study contributes to a broader understanding of how proactive insulation and thermal management can lead to significant energy and cost savings over a long-term period in industrial operations. Besides its contribution to sustainability goals: SDG7, SDG11, and SDG13, the study's approach proves its efficacity and can serve as a precedent for other industrial sites trying to enhance energy efficiency in their most energy-intensive areas.

ANALISIS PENGENDALIAN KUALITAS UNTUK MENGURANGI DEFECT PADA GLASS BOTTLE DENGAN MENGGUNAKAN METODE QUALITY CONTROL CIRCLE PT MULIAGLASS CONTAINER DIVISION CIKARANG JAWA BARAT

PT Muliaglass Container Division is a subsidiary of PT Mulia Industrindo, Tbk which is engaged in the glass industry by producing flat glass, glass block, glass packaging, and automotive safety glass as a result of its production. PT Muliaglass Container Division was founded in 1989. The quality control carried out by PT Muliaglass Container Division experienced problems in the Quality Control section or checking checkers, resulting in the defect pass rate so far exceeding the tolerance limits set by the company. There are several types of product defects in glass bottle packaging at PT Muliaglass Container Division, namely Check Ring, Check Under Ring, Leaner, Hot Mold Check, and others. To overcome the problems encountered, research is needed using the Quality Control Circle Method and Statistical Quality Control which are used to calculate how big the reasonable limit is in the product pass rate. After processing Statistical Quality Control data and knowing the number of acceptable quality labels for passing controlled defects or not, proceed with the Quality Control Circle Method, to find out what causes product defects to pass.

Out-of-Mold Sensor-Based Process Parameter Optimization and Adaptive Process Quality Control for Hot Runner Thin-Walled Injection-Molded Parts.

Injection molding is a highly nonlinear procedure that is easily influenced by various external factors, thereby affecting the stability of the product's quality. High-speed injection molding is required for production due to the rapid cooling characteristics of thin-walled parts, leading to increased manufacturing complexity. Consequently, establishing appropriate process parameters for maintaining quality stability in long-term production is challenging. This study selected a hot runner mold with a thin wall fitted with two external sensors, a nozzle pressure sensor and a tie-bar strain gauge, to collect data regarding the nozzle peak pressure, the timing of peak pressure, the viscosity index, and the clamping force difference value. The product weight was defined as the quality indicator, and a standardized parameter optimization process was constructed, including injection speed, V/P switchover point, packing, and clamping force. Finally, the optimized process parameters were applied to the adaptive process control experiments using the developed control system operated within the micro-controller unit (MCU). The results revealed that the control system effectively stabilized the product weight variation and standard deviation of 0.677% and 0.0178 g, respectively.

Dyeability and mechanical properties of banana fiber reinforced polypropylene composite

AbstractBanana fibers being highly strong and biodegradable, have always been an interesting aspect of polymer science. The research examines the pretreatment process to enhance the dyeability of banana fibers with synthetic dyes, followed by the preparation of polypropylene (PP) composites with dyed fibers to explore their mechanical properties. Raw banana fibers were extracted from the pseudo stems of banana plants for pretreating with sodium hydroxide and hydrogen peroxide and further dyed in the exhaust method using direct, basic, reactive, and vat dyes. Despite a decrease in fiber strength, the scoured‐bleached fibers appeared whiter and lustrous compared to untreated fibers. Direct dye exhibited a higher color strength (K/S) value of 20.7 and better wash fastness on average of 4‐3 rating compared to basic dye. Later polypropylene sheets were prepared using a Hot Plate Molding Machine, and composite specimens were fabricated by sandwiching the fibers between PP sheets and hot pressing. Fourier Transform Infrared Spectroscopy (FTIR) analysis revealed minor bond formations between the dyed fibers and polypropylene matrix in composites showing significant bonding at NH, CH, and OH regions. The composites containing dyed fibers showed slight improvements in tensile strength and modulus which is at best 2% than that of untreated fiber.Highlights Direct and basic dyes were determined as the most suitable synthetic dyes. FTIR analysis revealed minimal bond formation between the fiber and PP matrix. Composites having dyed banana fiber showed little better mechanical features.

Effect of Zirconia and Graphene Nanoparticles Loading on Thermo-Mechanical Performance of Hybrid Polymer Nanocomposite

This study demonstrates the development of a unique hybrid thermoplastic composite using reduced Graphene oxide (rGO) content and Zirconia (ZrO2) nanoparticles into the Ultra-High Molecular Weight Polyethylene (UHMWPE) biomaterials for continuous loading conditions. Specimens with different loadings of rGO (0 to 1.5 wt.%) and ZrO2 (5 to 10 wt.%) were fabricated using liquid phase ultrasonication followed by the hot press moulding method. The samples were analyzed using Thermogravimetric Analysis (TGA), Impact (Izod) testing, and Dynamic Mechanical Analysis (DMA). The developed material feasibility was assessed using Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray (EDX) analyses. The findings revealed that the 1 wt.% rGO/5 wt.% ZrO2/UHMWPE sample improved the storage modulus by 66.15%, and the Impact absorbed energy by 11.33% compared to the pristine UHMWPE. The proposed nanocomposite could be endorsed for artificial joints, prostheses, and other Artificial Bio-Bearing (ABB) applications.

Mechanical and crystallization properties of hot runner injection molded virgin and recycled polypropylene

AbstractAs the demand for sustainable and environmentally conscious practices continues to grow, recycled plastics have become increasingly popular for plastics manufacturers. However, reprocessing these materials can result in inconsistencies in both process and product quality, leading to a loss in mechanical properties. To address this issue, this work investigates the injection molding of recycled and virgin polypropylene (PP). Using a multi‐cavity hot runner mold, correlations between processing parameters, such as melt temperature, mold temperature, pack pressure, soak time, and mechanical properties, were systematically investigated. A multivariate analysis approach was used to model the variables for each material. Results indicated significant correlations between processing, mechanical properties, and morphology. In particular, for the PP, the melt temperature affected the formation of β‐crystals and their transition to α‐crystals upon tensile testing. Different morphology was observed for the recycled polypropylene (rPP), in which crystallization was affected by polyethylene (PE) contamination. The results discuss the injection molding polymer, structure, and properties, relationship providing an approach to understanding and optimizing the mechanical properties of rPP.Highlights Polyethylene contamination in polypropylene significantly influences crystallinity. Recycling contamination reduces the polypropylene's ability to form β crystals. Virgin polypropylene mechanical properties can be tailored through processing conditions. Recycled polypropylene mechanical properties suffer at higher temperatures and residence times. Polypropylene α/β morphologies can be visualized after mechanical testing.

Relation between water absorption and mechanical properties of flax 3D braided yarn woven fabric PLA bio-degradable composites

Natural fibre (flax) plain type of woven fabric is developed by using solid braided yarn and is utilised as filler material and PLA (polylactic acid) as a matrix. Solution casting is then used to create sheets of pure PLA and flax fabric–PLA. Composites are manufactured by sheets sequencing technique using the hot compression moulding method. Water absorption, thickness swelling and flexural tests are performed in loading directions of warp and weft of the composites. Results revealed that the absorption of water and swelling of thickness are enriched with an addition of flax fabric. The weft direction loaded composite displayed greater values of water uptake and thickness swelling. The warp direction loaded composites demonstrated the highest flexural strength (92.3 MPa) and modulus (4.5 GPa) compared to weft direction loaded composites. These values are decreased after water absorption.

Горячее деформирование сварных заготовок листов алюминиевого сплава 1565чМ

The details of forming in cold or heated position for welded blanks of alloy 1565chM with a thickness of 8,0 mm, performed by friction stir welding, are viewed. It is found that welded joints of alloy 1565chM with a thickness of 8,0 mm, obtained by friction stir welding have high strength properties together with sufficient toughness. Thus, bending angle of the joints is 165…170 °. The strength factor of the welded joint is 0.96 of the strength of the base metal. At the same time, the temporary resistance of the weld metal exceeds temporary resistance of both: base metal and the welded joint in its value. The 1565chM alloy joints, made by friction stir welding have good formability under cold deformation. This special feature of welded blanks made of 1565chM alloy sheets is explained by the presence of a fine-grained recrystallized structure in a stir zone, which is formed as a result of heat impact and force action of the working tool on the material to be welded. Welding modes providing specified mechanical properties of the joints were used for welding shells (blanks) of gas cylinders (liners). Manufacturing technique for such cylinders includes the following operations: welding of the shell, calibration of the shell, quality control of the weld on the shell, jumping into a hot mold for forming bottoms, welding of fittings and general tightness control. Experiments on forming liners bottoms due to the shell jumping into a heated to 450...500 °C mold have shown that there is an intensive weld metal runout due to differences in the strain capacity of the weld metal and the base metal. This behavior of the weld metal during hot forming can be explained by superductility of the weld metal owing to the presence of a recrystallized ultrafine-grained structure. It was found that starting from a temperature of 400 °C, the relative elongation of the weld metal significantly exceeds the elongation value of the base metal. In case of 450 °C, this difference reaches 
 72 %. For the weld of the 1565chM alloy, starting from the heating temperature of 540 °C, an abnormal grain growth occurs along the entire weld.

The response of glass fibre reinforced PEKK laminates subjected to single and multiple impact loading

This paper presents a study on the impact behaviour of newly-developed composites based on S-glass fibre reinforced PEKK (GF/PEKK) composites subjected to single and repeated impact loading. The laminates, with a thickness of 2 mm and fibre weigh fraction of 60 wt%, were manufactured by stacking eight plies of GF/PEKK woven prepregs using a hot compression moulding technique, and impacted centrally using a drop-weight apparatus. Beginning with a single impact test, these samples were subjected to repeated impacts using the same projectile and energy until full perforation was achieved. During each test, the impact response characteristics, contact force, velocity, displacement and energy absorption with respect to time were measured and recorded. The results show that, for a single impact test, the absorbed energy increases significantly at low impact energies, while repeated impacts lead to a decrease in the values of peak force and stiffness of the composite panels. Here, up to 5 times of energy can be absorbed over multiple low energy impacts compared to that required to perforate the target with a single impact. For multiple impacts at different impact energy levels, accumulation of damaged area increases rapidly around the impact location up to perforation failure (e.g. the rate of damage from 2 mm2 per impact at 1 J case jumping to 25 mm2 per impact at 2 J case, further to 68 mm2 per impact at 3 J case). The rate of damage progression (per impact) appears to be related strongly to the rate of energy absorption. The continuous nature of the absorbed energy and damage progression over multiple impacts suggest that semi-empirical analytical relationships, similar to that used in a fatigue analysis, could be useful in providing a means of assessing impact damage in a laminated structure and predicting the remaining ‘impact fatigue’ life.

A review on plastic waste valorisation to advanced materials: Solutions and technologies to curb plastic waste pollution

Plastic's low cost, versatile and durable nature has rendered it a popular material in the market. Such inevitable high demand has resulted in overwhelming production on a global scale, leading to the generation of a large quantity of plastic waste (PW). The recycling of PW is challenging due to its low degradability and quality loss after each cycle. Large quantities of PW are dumped into the ocean or end up in landfills annually. Due to long-term environmental exposures, plastic degrades into micro-sized particles, which pose severe threats to human health, marine life, and the environment. To overcome this issue, numerous researchers have made efforts to transform PW into useful resources before their degradation into microplastics, which cause secondary pollution. This paper aims to comprehensively review the transformation of PW into advanced materials, fuels, and chemicals through various valorisation technologies. Valorisation technologies including thermal (combustion, torrefaction, pyrolysis, hydrothermal liquefaction, carbonization and one-step hot moulding), biological (microbial and enzymatic degradation) and physical approaches (plastic recycling) that deconstruct plastics into useful chemical intermediates are critically reviewed. The products obtained from the technologies, their resultant properties, and potential applications are highlighted. The detailed studies in these areas could provide insights into sustainable PW management and generate positive economic value. Therefore, further research and development are needed to improve the current technologies to reduce pollution from plastic trash. Collaborative efforts between governments, industries, and research institutes are essential for establishing supportive regulatory frameworks.

Fabrication of functionalised graphene-PAEK nanocomposites for different manufacturing processes

ABSTRACTAchieving good dispersion of graphene (GNP), in polyetheretherketone (PEEK), is challenging due to the high melt viscosity, solvent resistance and processing temperature of PEEK. In addition, certain manufacturing processes tend to enhance the anisotropy due to GNP orientation within the structure. This study investigated the fabrication of nanocomposite parts through hot compression moulding (C-MOULD) and powder bed fusion (PBF) processes, using powder with GNPs fused to the surface of polymeric particles, through a process called mechanofusion. The method applies mechanical forces of compression, shear and impact to generate a mechanical bond between materials, in this case, O2 functionalised GNP and a developmental polyaryletherketones (PAEK) grade powder. The novelty of this work is in the combination of processes used for manufacturing (material preparation and actual manufacturing processes), which are scalable and efficient in comparison with existing methods (such as solvent mixing or melt-compounding). The mechanofusion GNP-PAEK composite powders were successfully printed for the first time using the EOS P800 system with notable improvements in electrical and mechanical properties. This study highlights that the mechanofusion process could be used as an efficient process for making multifunctional nanocomposite materials and this can be combined with additive manufacturing (AM) processes to produce complex components.

Hot Tearing, Parameters, and Mould Types for Observation – Review

Hot Tearing, Parameters, and Mould Types for Observation – Review

Hot Work Mold Repaired via Hot Isostatic Pressing towards High Red Hardness

Repairing hot work molds can extend their lifespans and reduce the production costs. This study presents a proposed method for enhancing the red hardness and strength of repaired molds. The method involves utilizing PM23 high-speed steel powder to repair H13 steel molds with two distinct surface states through the process of hot isostatic pressing (HIP). The internal microstructure changes, bonding state, fracture morphology, and crack extension behaviors of the repaired molds are characterized using scanning electron microscopy and electron backscatter diffraction technology. Additionally, the mechanical properties, including red hardness and tensile strength, are quantitatively analyzed. The findings indicate that the repaired area in the sandblasted sample exhibits a rough and uneven structure, demonstrating exceptional toughness. The tensile strength of the repaired region is approximately 1195.42 MPa, while the hardness measures around 672.8 HV. These properties effectively enhance the performance of the molds. The experimental findings indicate that HIP can effectively restore molds, resulting in enhanced red hardness and improved toughness, particularly when combined with sandblasting as a pretreatment method.

Study on the in situ strengthening and toughening mechanism of H13 tool steel/WC-12Co composite using laser-based directed energy deposition

To overcome the unworkability of hot work molds in conventional manufacturing, laser additive manufacturing (AM) is widely adopted to print molds/dies with complex internal structures. However, in the AM process, some hot work steels easily crack (e.g., H11 and H13 tool steel) or exhibit dissatisfactory wear resistance (e.g., MS1 maraging steel). To tackle this issue, toughened functionally graded metal matrix/ceramic composite materials can be fabricated on existing molds by laser directed energy deposition (L-DED). Contrary to previous studies that clad Co on WC to avoid the decomposition of ceramic, in this work, we innovatively utilized a type of WC-12Co powder with a substructure to accelerate its decomposition and improve the toughness of composites. It was found that the unmelted tens-micrometer-magnitude WC-12Co powder and in situ synthesized nano WC coexist in the laser-deposited H13 steel/WC-12Co composites to act as the reinforcement phase. Particularly, all the brittle phases (WC and FexWxC) are wrapped by soft γ phases, alleviating the coefficient of thermal expansion (CET) mismatch between materials and the residual stress generated by laser AM. Consequently, defect-free deposits with varied WC contents are manufactured by L-DED and exhibit high hardness and superior wear resistance at both room and elevated temperatures due to the second phase and grain refinement strengthening mechanisms. These findings provide a disparate metal matrix composite design route for laser additive manufacturing to improve the toughness of metal matrix/ceramic composite materials and obtain exceptional performance.

Effect of Ultrasonic Rolling on the Organization and Properties of a High-Speed Laser Cladding IN 718 Superalloy Coating

To repair or improve the performance of H13 hot working molds through the additive manufacturing process, IN 718 was coated on H13 die steel by high-speed laser cladding followed by an ultrasonic surface rolling process (USRP). The mechanism of ultrasonic surface rolling on the mechanical properties of the coating was studied. After USRP, the coating exhibited severe plastic deformation; the microscopic organization of the surface layer was refined and the particle size was significantly reduced. The violent plastic deformation of the coating caused by USRP improved the dislocation density and the grain boundary density, providing an improved yield strength of the coating and improving the high-temperature wear resistance of the coating. After USRP, the surface hardness of the coating increased by 30%. Compared with the coating without USRP, the wear resistance of the coating greatly improved; the wear rate was reduced by 51% and the wear mechanism of the coating changed from large-area adhesive wear and severe abrasive wear to small-area adhesive wear and slight abrasive wear. The IN 718 coating after USRP had a higher hardness and greater wear resistance, significantly improving the service life of H13 steel.

Study of mechanical properties of sustainable biocomposite panels using Jute-PLA and Sisal-PLA

In recent years, bio composites have experienced significant growth and have found applications in various sectors, like domestic use, aerospace, circuit boards, and automotive industries. Extensive research has been conducted on natural fibres to develop it as composite materials so that can compete with synthetic fibre composites. Jute and sisal fibres with Polylactic acid (PLA) means fully biodegradable and recyclable, offer an environmentally friendly solution. The fabrication of the bio-composite specimen involved the utilization of a hot press moulding machine. The maximum strength and bending properties, including ductility, were assessed through flexural and tensile tests following ASTM standards. Free vibration analysis was conducted to determine important characteristics like damping frequency, damping ratio, and natural frequency of the bio composites. The resonant set obtained for Sisal/PLA is inferior to Jute/PLA composites, which clearly demonstrates the influence of fibre in resonant behaviour of the composites. Further Sisal/PLA composites show 20% rise in damping performance at first two resonant sets and 30% in the third resonant. This free vibration characterization of most widely used to composites provides valuable insights into the practical usage under suitable environment conditions.

Study on injection molding parameters on PET with bio-plastic material and hot runner mold

Trend of global warming is increasingly interested for everyone who concerns on sustainability in terms of material used in production process. Plastic material is widely used in general industry. Presently, PET is used instead of common plastic together with bio-plastic that can be degradable after end of life. PET together with bio-plastic like PLA is more concerned for plastic product design particularly packaging, container, bottle and so on. However, there are rarely studied on plastic injection molding parameters and the impact on quality of preforms prior to both injection and blow molding the final products. The paper proposes simulation and design of experiment on plastic injection and blow molding parameters using PET + PLA Bio plastic material under the condition of hot runner. Case study is applied on a preform water bottle design. There are three factors which are concerned; machine, mold and plastics material. Due to rarely knowledge and information about the plastic injection molding parameters on using PET + PLA, plastic injection molding parameter is studied in this work. Simulation is on MOLDEX together with DOE of the Taguchi method. The study is investigated on controlling plastic injection molding such as melt temperature, mold temperature, packing pressure, and cooling time in each stage. Plastic flow simulation is created and tested. The results are discussed in details.

Manufacturing of Composite Panels from Date Palm Leaflet and Expanded Polystyrene Wastes Using Hot Compression Moulding Process

Manufacturing of Composite Panels from Date Palm Leaflet and Expanded Polystyrene Wastes Using Hot Compression Moulding Process