Injection Moulding Research Articles

Towards sustainable injection moulding using 3D printed conformal cooling channels: a comparative simulation study

In recent years, studies have proven that conformal cooling channels (CCC) in an additively manufactured mould result in a more efficient and effective injection moulding process. This can be achieved since CCCs are designed to follow the contour of the part being moulded so that the surface of the part is equidistant from the channel at all points. However, no studies were found which explored the combined effect of mould material thermal conductivity and varying cooling channel designs on the cooling performance of the mould from a sustainability point of view. Within this context, a study was carried out to explore the effect of the tool material’s thermal conductivity on the performance of various CCC designs in comparison with conventional, straight drilled cooling channels. The performance of the cooling channels was analysed from a sustainability point of view by comparing the channel performances in terms of energy consumption, financial implications, and the resulting quality of the part. The results of this study showed that the higher conductivity alloys were especially effective at reducing the cycle time and improving the energy performance of the process in the conventional cooling channel designs. These materials were also capable of reducing the overall cost of the process which was calculated in terms of material costs and electricity consumption. For the CCC designs, however, the high conductivity alloys were less effective in all aspects of this analysis, namely cooling time, energy efficiency, and overall costs. However, it is worth noting that based on the melt flow simulations, the alternative materials had little to no effect on the resulting quality of the part.

Enhancing Complex Injection Mold Design Validation Using Multicombined RV Environments

Enhancing Complex Injection Mold Design Validation Using Multicombined RV Environments

Synthesis and Behavior Study of Basalt Fiber-Made Low-Density Polyethylene Composites Via Injection Mold

Synthesis and Behavior Study of Basalt Fiber-Made Low-Density Polyethylene Composites Via Injection Mold

Numerical Modelling of Microcellular Foaming Injection Moulding

The results of computer modelling of an injection moulding process with microcellular foaming (MuCell®) were presented in this work. The process is based on the dissolving nitrogen in a liquid polymer which is possible when nitrogen is in supercritical fluid state (SCF). After pressure drop of the melt in the injection mould the intensive nucleation of pores occurs and, as the result, the material with high concentration of small pores is created. The pores obtained in this way are of much smaller size than in a conventional foaming process. The pore size in the cross-section of an exemplary injection moulded part was calculated in the computer modelling and compared to the results of microscopical investigation made on the real injection moulded part. It was found that the size of the pores depends on the flow length inside the injection mould and on the position in the part’s cross-section.

A Concise Review on Materials for Injection Moulds and Their Conventional and Non-Conventional Machining Processes

Injection moulds are crucial to produce plastic and lightweight metal components. One primary associated challenge is that these may suffer from different types of failures, such as wear and/or cracking, due to the extreme temperatures (T), thermal cycles, and pressures involved in the production process. According to the intended geometry and respective needs, mould manufacturing can be performed with conventional or non-conventional processes. This work focuses on three foremost alloys: AMPCO® (CuBe alloy), INVAR-36® (Fe-Ni alloys, Fe-Ni36), and heat-treated (HT) steels. An insight into the manufacturing processes’ limitations of these kinds of materials will be made, and solutions for more effective machining will be presented by reviewing other published works from the last decade. The main objective is to provide a concise and comprehensive review of the most recent investigations of these alloys’ manufacturing processes and present the machinability challenges from other authors, discovering the prospects for future work and contributing to the endeavours of the injection mould industry. This review highlighted the imperative for more extensive research and development in targeted domains.

Combining 3D printing and injection moulding for the fabrication of polymer micro-components with internal hollow features

There is a need to cost-effectively produce polymer components with meso/micro-scale internal geometries with high replication accuracy without the use of post-processing steps. A possible process chain to produce such polymer components with internal hollow features is by combining the 3D printing (3DP) and micro-injection moulding (MIM) processes. To date, no studies were carried out to explore the feasibility of such a process chain. Consequently, this experimental study investigated the use of the 3DP lost-cores that are over-moulded using the MIM process. The first step involved the production of lost-core from a soluble polymer material where three different materials were studied: two filament-based materials (Xioneer VXL130 and AquaSys180) and one resin-based material (IM-HDT-WS). The filament-based materials were printed on an Ultimaker S5 (filament fused fabrication) and the resin-based material was printed using an Asiga Max X27 (digital light processing). In the second step, the lost core was then over-moulded with polymethyl methacrylate (PMMA) using the MIM process. After demoulding, the internal core was then dissolved using the respective dissolution method of each material to achieve a part with meso/micro scale internal features. Investigations carried out at the different stages of the process chain revealed that the best dimensional accuracy was achieved when using the IM-HDT-WS material in the 3DP of the lost-cores and their subsequent over-moulding to form the case study part internal geometry. In particular, the dimensional analysis of the replicated IM-HDT-WS lost-core geometries onto the over-moulded PMMA revealed a difference of 0% in diameter and − 3.17% in bifurcation angle of the Y1.6 channel and a difference of + 4.88% in diameter and + 11.48% in bifurcation angle of the Y0.8 channels when compared to the respective 3DP core dimensional values prior to encapsulation. However, dissolution tests revealed that the filament-based material, the Xioneer VXL130, achieved a dissolution rate of 3.5 and 4.5 h for the Y1.6 and Y0.8 channel, respectively, which was marginally faster than that of the IM-HDT-WS.

The Effect of Blending Ratio on the Structure and Properties of the PPR/PS In situ Fiber Reinforced System Prepared by Multi-Flow Vibration Injection Molding

The Effect of Blending Ratio on the Structure and Properties of the PPR/PS In situ Fiber Reinforced System Prepared by Multi-Flow Vibration Injection Molding

Polymer Waste Recycling of Injection Molding Purges with Softening for Cutting with Fresnel Solar Collector-A Real Problem Linked to Sustainability and the Circular Economy.

A plastic injection waste known as "purge" cannot be reintegrated into the recycling chain due to its shape, size, and composition. Grinding these cannot be carried out with traditional mills due to significant variations in size and shape. This work proposes a process and the design of a device that operates with solar energy to cut the purges without exceeding the degradation temperature. The size reduction allows reprocessing, revalorization, and handling. The purges are mixtures of processed polymers, so their characterization information is unavailable. Some characterizations were conducted before the design of the process and after the cut of the purges. Some of the most representative purges in a recycling company were evaluated. The flame test determines that all material mixtures retain thermoplasticity. The hardness (Shore D) presented changes in four of the purges being assessed, with results in a range of 59-71 before softening and 60-68 after softening. Young's modulus was analyzed by the impulse excitation technique (IET), which was 2.38-3.95 GPa before softening and 1.7-4.28 after softening. The feasibility of cutting purges at their softening temperature was evaluated. This was achieved in all the purges evaluated at 250-280 °C. FTIR allowed for corroboration of no significant change in the purges after softening. The five types of purges evaluated were polypropylene-ABS, polycarbonate-ABS-polypropylene, yellow nylon 66, acetal, and black nylon 66 with fillers, and all were easily cut at their softening temperature, allowing their manipulation in subsequent process steps.

Preparation of High-Density Polypropylene Composite Featured with Natural Neem Fiber Through Injection Mould Route

Preparation of High-Density Polypropylene Composite Featured with Natural Neem Fiber Through Injection Mould Route

Degradation characteristics of the pineapple leaf fibre reinforced green composite developed by injection moulding under different environmental conditions

The present study examines the mechanical and morphological characteristics of a green composite reinforced with pineapple leaf fiber (PLF) under different environmental conditions. PLF underwent chemical treatment at optimal conditions, using a 1% w/v sodium carbonate solution for 6 hours, to produce an environmentally friendly pineapple leaf fiber (PLF)/polylactic acid (PLA)-based composite via injection molding. The optimal injection settings of 165℃ (melting temperature), 50 mm/sec (injection speed), and 110 bars (injection pressure) to produce the PLF/PLA composite. The PLF/PLA composite was developed with a fiber loading of 20% and a length of 3 mm. The produced PLF/PLA composites were then exposed to a variety of environmental conditions, including water, soil, refrigeration, and room temperature. The impact of these diverse conditions on the mechanical properties (tensile, flexural, compression, and shear) was scientifically observed for four-week. Additionally, the morphology of the fractured specimens was assessed using a scanning electron microscope (SEM). The contact angle measurement was conducted to assess the hydrophilic characteristics of the PLF/PLA green composite. There has been a lack of comprehensive research on the effects of different environmental conditions on the mechanical, wettability, and morphological properties of green composites derived from PLF/PLA. Thus, in this study, emphasis is given for investigating the effect of various environmental conditions on the mechanical properties of PLF/PLA injection-molded green composite. The composite material demonstrated the highest water absorption and swelling thickness at 6.45% and 5.51%, respectively, in comparison to the dry PLF/PLA samples. The green composite of PLF/PLA demonstrated excellent mechanical performance under ambient conditions compared to other environmental conditions. The PLF/PLA composite displayed a peak contact angle of 83.26° when subjected to soil burial conditions. On the contrary, the initial samples of the PLF/PLA composite displayed the minimum contact angle of 56.72°.

Optimization of Runner Balance for a Family Product of Injection Molding Process

A family mold is used in the injection molding process to produce components of different sizes that would normally be assembled into a single product assembly. The uniform quality of each injection molded part is strongly influenced by the filling balance of the mold cavity. The filling balance can be controlled by optimizing the dimensions of runners that are directed towards each cavity. In this paper, an optimization method is proposed that aims at balancing the filling time that maximizes the quality of a family mold cavity. There are two steps proposed in this research, namely theoretical calculations and simulation of runner balanced design using the software. The results of this study can be used as a practical reference in designing a mold for family products to avoid design errors as early as possible. The result obtained from an industrial case study highlighted the effectiveness of the proposed approach in finding the optimal runner dimension by a restricted number of simulations.

Role of processing procedures and molecular weight and their link to quasistatic and fatigue properties of polyamide 6

To expand the scientific base for the usage of the fused layer modelling (FLM) process for the production of polyamide 6 (PA 6) parts, in this work the influence of processing (injection moulding, compression moulding and FLM) and molecular weight on the end-use properties of PA 6 is elucidated. Besides its viscosity, the molecular weight of PA 6 also influences crystallinity and crystallization temperature. The mechanical properties of the fabricated specimens were studied in detail, also in the fatigue range, and analysed focusing on the fusion of interfaces in compression moulding and fused layer modelling. The analysis reveals, that the molecular mobility in the melt (i.e. viscosity and diffusion coefficient) as well as the amount and orientation of interfaces (as determined by the processing procedure) strongly influences the end-use properties. In the case of FLM printed parts, mechanical failure due to quasistatic and fatigue loading essentially depends on the quality of fusion of adjacent layers, which is strongly determined by molecular weight and processing temperature. Generally, a lower viscosity of PA 6 favours fusion of adjacent layers.

Sapindus Mukurossi - An Effective Biocleanser for Removable Dental Prostheses? An In vitro Study.

This study aims to determine the efficient concentration of Sapindus mukorossi that can be used as a denture cleanser. 60 heat cure denture base resin specimens of dimensions 10*10*2 mm were fabricated. Among these, 30 were fabricated by compression moulding technique and the remaining 30 by an injection moulding technique. The samples inoculated with Candida albicans and Streptococcus mutans were subjected to denture cleansing protocols using a medicinal herbal extract from the Sapindus mukorossi, at various concentrations [15%, 20%, and 25%]. The colony-forming unit [CFU] values were evaluated using a microprocessor colony counter. The statistical analysis was performed. The intragroup comparison showed a statistically significant difference between all groups except the compression moulded samples inoculated with Streptococcus mutans. The intergroup comparison revealed no statistically significant differences between the compared groups. The reduction in CFU values is evident in the effective anti-microbial activity of Sapindus mukorossi. A concentration of 25% Sapindus mukorossi solution showed the greatest efficiency. The maximum anti-microbial activity was observed against Candida albicans in a 25% concentration of Sapindus mukorossi. Among all, injection moulded samples showed better results.

Methodology of a thermal injection mold design with locally applied heating coatings on the cavity wall

AbstractThe thermal balance of injection molds is defined by the cooling channel layout. However, the fluid tempering of injection molds underlies certain restrictions concerning the thermal dynamic and the local limitation of the zone of influence. The optimal heat balance within the mold to minimize warpage cannot be solely achieved with conformal cooling channels. Ceramic heating coating systems applied by Thermal Spraying on the cavity wall are a novel tempering method for high heating rates and offer the possibility of a more local heat input. In terms of the thermal mold design, the position and size of local heating coating systems need to be determined. A methodology is proposed, which connects the optimization of part warpage by defining the necessary local heat flux within the mold with the determination of the heating coating placement. Due to the dependence of the coating placement on the heating time and the power, different decision criteria of these parameters are discussed with regard to the process efficiency. The developed methodology can calculate the necessary heating power distribution to homogenize the surface temperature and freeze time. A second step discretizes the heating power distribution to certain manufacturable heating zones.

Assessment of Residual Stress Behavior and Material Properties in Steels Produced via Oxynitrocarburized Metal Injection Molding

Assessment of Residual Stress Behavior and Material Properties in Steels Produced via Oxynitrocarburized Metal Injection Molding

3D Printing of Flow Profiles for Inspection Chambers and Manholes

For years the way of producing a flow profile for Inspection Chambers and Manholes could be divided into 3 methods: Injection moulding, Roto moulding and Hand assembling. For the standard orientations, for example straight through and cross, the IM profile integrated with a base is by far the best option. But for nonstandard configurations; different orientations, inlet heights and inlet sizes, the only option is to hand weld them together from injection moulded parts, pipes and plates. This is a time- consuming way of producing with high production cost and often aesthetic-wise of a challenging level. This is not necessary anymore after the introduction of 3D printing as a new production method for flow profiles in chambers and manholes. 3D printing is in many industries an accepted production method which can produce parts of high quality and high accuracy. The printing systems have faced a huge development in the last 10 years and prints are often close to perfection. The only disadvantage of these printing systems is the maximum size of the print. But since the introduction of 3D robot printing, products with a diameter of 1 meter can be printed without any problem. 3D robot printers were up to recently, used for prototypes, one- off products and art objects. Now a production area is created on which multiple products can be produced in a row without human interference. The most common materials used for 3D printing are ABS and PLA. These materials have good adhesion, almost no shrinkage and a good appearance. Unfortunately, these materials are not common in our industry. We need PP, PE or PVC. While our manholes and inspection chambers are from PP, we also need PP flow profiles. The advantage of using a 3D robot printer is that it uses granulates instead of filaments or special powder. This makes the material cost part almost equal to injection moulding. Another advantage is also that recycled material can be used. Own scrap can be used but also waste from other markets. The main reason that flows profiles are ideal for 3D printing is that nonstandard flow profiles are very labour-intensive. So, 3D printing really helps out here. Besides that, there is a lot of freedom in design. This helps to design in such a way, that the final profile is hydraulically optimal. This prevents the overflowing of manholes during heavy rain showers. Of course, these products should fulfil all requirements of the EN13598-2. Even though major development steps have been made in 3D printing during the last 5 years, 3D robot printing is still in the exploring phase and we find many hurdles on our way. This paper will show how our industry can use 3D printing and what are the pros and cons.

Moldability and Solvent Debinding of Hydroxyapatite Micro-Part Processed through Micro-Powder Injection Molding

The development of the micro-powder injection molding (µPIM) process from the powder injection molding (PIM) process has been prompted by the demand of the worldwide market to produce micro-sized components. The need for µPIM-processed components is currently rising across a range of industries, including automotive, aerospace, food, biomedical, electronics, and telecommunications. In the current research work, homogeneous HA feedstock with a powder loading of 57 vol.% was prepared by mixing HA powder particles with palm stearin and low-density polyethylene (LDPE) binders at a mixing temperature of 150 °C for 6 h. Defect-free injection molded or green micro-sized components of HA were produced by employing injection pressure, injection time, mold temperature, and melt temperature of 12 bar, 5 s, 110 °C, and 180 °C, respectively. When mold temperatures less than 110 °C were used, short shot defects were frequently observed in green specimens. After solvent debinding at 60 °C for 50 min, 82.2% of the palm stearin was removed from the green part. No difference in dimension between the solvent debound part and the green part was noticed. An open-pore structure developed in the solvent debound HA microcomponent is helpful for eliminating the insoluble LDPE binder during the thermal debinding phase.

Evaluation of the Corrosion Resistance of Watch Links from 316L and 904L Austenitic Stainless Steels Obtained by the Metal Injection Molding (MIM) Technique Intended to Be in Contact with Human Skin

Watchmaking manufacturers obtain their bracelet links from machining drawn metal profiles. But, today, there is another process that represents an alternative to manufacture them: metal injection molding using metal powders (MIM technology). This process is less expensive than the machining of drawn metal profiles. The aim of this study was to evaluate the corrosion behavior and the nickel cation release of two stainless steel alloys: 316L MIM and 904L MIM. The general corrosion behavior was evaluated by the rotating electrode technique; the galvanic corrosion measurements were conducted with a 316L AISI bulk coupling partner. The pitting corrosion behavior was evaluated in FeCl3 0.5 M media (according to ASTM G48-11). For comparison, a complementary study was conducted on 316L and 904L bulk alloys. The Ni cation release tests were conducted on 316L and 904L MIM and bulk samples according to EN 1811. Different electrochemical parameters were measured and calculated (open circuit potential, polarization resistance, corrosion current and Tafel slopes, coulometric analysis). Generally, if MIM steels are compared with conventional steels, their corrosion resistance behavior is inferior. In the couplings studied, the galvanic currents generated are very important. The shape of the curves also reveals the presence of localized corrosion phenomena. According to tests in ferric chloride, MIM steels were noted to have inferior behavior compared to conventional steels. MIM type 904L steels are comparable in behavior to conventional type 316L steels. The quantities of nickel released according to EN 1811 were very significant (2 mg cm−2 week−1 up to 24 mg cm−2 week−1) and did not meet the requirements of the European directive (0.5 µg cm−2 week−1). In conclusion, conventional steels studied under the same experimental conditions revealed a better behavior compared to MIM steels independently of the phenomenological parameters chosen.

Development and Characterization of Poly(butylene succinate‐co‐adipate)/Poly(3‐hydroxybutyrate‐co‐3‐hydroxyvalerate) with Cowpea Lignocellulosic Fibers as a Filler via Injection Molding and Extrusion Film‐Casting

AbstractBiodegradable poly(butylene succinate‐co‐adipate)/Poly(3‐hydroxybutyrate‐co‐3‐hydoxyvalerate) (PBSA/PHBV) filled with lignocellulosic sidestream/fibers from cowpea, a neglected and underutilized African crop are produced by injection molding and extrusion film casting. Differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA) suggests that the fibers have more affinity and interfacial interaction with PBSA than PHBV. This is shown by a decrease in dampening of PBSA and an increase in dampening of PHBV with fiber addition. In addition, fiber addition results in more homogeneous crystal morphology of PBSA, while resulting in more heterogeneous crystal morphology of PHBV. The tensile strength of injection molded bio‐composites increases with fiber addition due to good interfacial adhesion between the matrix and fibers revealed by scanning electron microscope. In contrast, the tensile strength of bio‐composite films decreases with fiber addition due to the high‐volume fraction of pores in bio‐composite films that act as stress raisers. The stiffness of both injection molded, and bio‐composite films increase with fiber addition, as revealed by an increase in Young's modulus and storage modulus, while the tensile strain decreases. In conclusion, low‐value cowpea sidestream can be used as a filler to produce injection molded bio‐composites and bio‐composite films for potential application as rigid and flexible packaging.

Investigation and chemical processing effect of sisal fiber epoxy composite characteristic enhancement with nano-SiC via injection mold

Investigation and chemical processing effect of sisal fiber epoxy composite characteristic enhancement with nano-SiC via injection mold