Performance evaluation of conformal and straight cooling channels on injection moulded part

In injection moulding process, warpage is one of the main quality aspects measured for moulded parts while cycle time to produce a part indicates the efficiency of the process. Efficient cooling is a huge challenge to many mould designers for achieving a uniform thermal distribution in an injection mould where it affects both quality and productivity. The use of conformal cooling design has been reported as very effective to distribute thermal uniformly, thus able to improve part quality as well as reducing moulding cycle time. However, most of previous researchers only focused on simulation studies and they hardly performed experimental works to verify the simulation results. In this study, a Milled Groove Square Shape (MGSS) conformal cooling channel has been designed, simulated, fabricated and tested using a front panel housing as the case study. Performance evaluations on the MGSS conformal cooling channel and straight cooling channel were conducted using simulation and experimental works in terms of quality (warpage) and productivity (cycle time) of the moulded part. Mould and coolant input temperatures were varied in both evaluations, i.e. mould temperature (40 oC to 80 oC) and coolant temperature (25 oC to 65 oC). Results showed that the MGSS conformal cooling was superior with improved cycle time from 37.57% to 48.66% (simulation) and confirmed by experimental trials (27.89% to 36.15%). Simulated results showed that there is no warpage on the front panel housing in x direction for both types of cooling channels. However, experimental results indicated that warpage occurs in x direction in both cooling channel designs, but MGSS conformal cooling type demonstrates more reduction from 36.36% to 76%. Similarly, warpage in y direction recorded a remarkable improvement within the range of 34.3% to 41.5% and 16.7% to 35.48% respectively from the simulated and experimental results when employing the MGSS conformal cooling channel. The fabrication cost of the MGSS conformal cooling channel is approximately 3 % to 5 % higher which depends on the complexity of part shape as compared to the straight cooling channel. The finding shows that the MGSS conformal cooling channel design offers very encouraging results which is able to improve part quality as well as productivity at an acceptable manufacturing cost

Characterization of flow rate and Heat Loss in Heating, Ventilation and Air Conditioning (HVAC) Duct System for Office Building

A building is an assemblage that is firmly attached to the ground and provides the performance of human activities and need to be considered in the daily operation in that building. The improvements in building performance are focused on improving the energy efficiency of buildings. This is approach by designing heating, ventilation and air conditioning (HVAC) duct system due to one of the most utilized energy in maintaining building performance and environment. The objectives of this research is to calculate the air (CFM) supply in office building, to characterize the velocity and head loss in a round and rectangular HVAC ducting system at various duct thickness and to optimize the thickness of the duct in HVAC system according to ASHRAE Standard. The increasing of velocity in duct system shows the increasing of head loss. The round duct design gives the lowest velocity and head loss in HVAC system approximately around 9.35% as compared to rectangular duct at 0.06 inches thickness. Hence, the trends of the head loss and duct thickness has influenced in reducing noise in HVAC duct system in order to select the best design concepts which is round shape design

Effect of degassing addition on the solidification of nickel aluminum bronze

The effect of degassing agent addition on the solidification of Nickel Aluminum Bronze was investigated. The complex relationship between the development of the alloy solidification and its thermal analysis in Nickel Aluminum Bronze was obtained by using data logger. This experiment describes the characterization of thermal analysis in Nickel Aluminum Bronze which was interpret using solidification cooling curve. With this method, the differences of temperature points during solidification were clearly evidenced. The results show a solidification cooling curve directly affected by percentage of degassing agent added in molten Nickel Aluminum Bronze alloy. There is distribution of temperature point after solidification from melting. As for degassing treatment, higher degassing addition on the Nickel Aluminum Bronze decreased the solidification temperature point

Effect of spent coffee grounds and rice husk amount towards the swelling properties of hydrogel using graft polymerization

Hydrogels are widely known for their ability to absorb water without being dissolved. This characteristic, which is known as swelling has been studied by many researchers in various sectors such as medicine, pharmacy, agriculture, health science and many more. This paper presents a study on the swelling properties of hydrogel that was grafted with spent coffee grounds and rice husk ash. The hydrogel was prepared with acrylic acid as the monomer and acrylamide as the co-monomer. The hydrogel was grafted with spent coffee grounds and rice husk ash separately, with varied weight percent (wt%). The hydrogel was characterized using Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM), Thermal Gravimetric Analysis (TGA) and Differential Scanning Calorimetry (DSC). The 0.1 (wt%) rice husk ash grafted hydrogel has the best swelling properties as shown by the highest water absorption, with the most porous structure and the highest crystalline temperature (122.0 °C). The FTIR wavenumber showed that the hydrogel is grafted properly as new wavenumbers are formed, whereas the TGA analysis shown that it had the highest decomposition temperature (658.6 °C)

Mechanical and durability analysis of fly ash based geopolymer with various compositions for rigid pavement applications

Ordinary Portland cement (OPC) is a conventional material used to construct rigid pave�ment that emits large amounts of carbon dioxide (CO2 ) during its manufacturing process, which is bad for the environment. It is also claimed that OPC is susceptible to acid attack, which increases the maintenance cost of rigid pavement. Therefore, a fly ash based geopolymer is proposed as a material for rigid pavement application as it releases lesser amounts of CO2 during the synthesis process and has higher acid resistance compared to OPC. This current study optimizes the formulation to produce fly ash based geopolymer with the highest compressive strength. In addition, the durability of fly ash based geopolymer concrete and OPC concrete in an acidic environment is also determined and compared. The results show that the optimum value of sodium hydroxide concentration, the ratio of sodium silicate to sodium hydroxide, and the ratio of solid-to-liquid for fly ash based geopolymer are 10 M, 2.0, and 2.5, respectively, with a maximum compressive strength of 47 MPa. The results also highlight that the durability of fly ash based geopolymer is higher than that of OPC concrete, indicating that fly ash based geopolymer is a better material for rigid pavement applications, with a percentage of compressive strength loss of 7.38% to 21.94% for OPC concrete. This current study contributes to the field of knowledge by providing a reference for future development of fly ash based geopolymer for rigid pavement applications

Microstructure and high temperature oxidation of modified ductile ni-resist alloy with higher manganese content

In this study, ductile Ni-resist with a minimum of 18 wt% nickel composition was modified. Up to 12 wt% manganese was added together with 10 wt% nickel to investigate the effects of the alloying elements on its microstructure, mechanical properties and isothermal oxidation behaviour. The results show a higher manganese composition on modified ductile Ni-resist with increased carbide formation, and a slightly decreased elevated temperature tensile strength. The addition of higher Mn [wt%] slightly increased the oxidation resistance. Three different oxide layers were observed on the modified ductile Ni-resist after 25 h hot corrosion at 765◦C

A review on graft compatibilizer for thermoplastic elastomer blend

A biodegradable thermoplastic elastomer (TPE) blend is developed by blending poly (lactic acid) (PLA) and natural rubber (NR) or epoxidized natural rubber (ENR) and it is a sustainable substitution in recent years for synthetic polymers. PLA is high in mechanical strength and compostable, but it is highly stiff and brittle. The incorporation of NR or ENR to PLA increases the impact strength and toughness of PLA. However, the disparity in polarity between PLA and elastomer phase like NR and ENR results in TPE blend being incompatible. Hence, compatibilization is essential to improve its polarity and develop interactions. Compatibilizer that composed of two different polymer is known is graft compatibilizer with the aid of grafting agent. The graft compatibilizers are divided into two categories. The first type is made up of one polymer and grafting agent and, the other one is composed of two polymer groups and grafting agent. These two types of graft compatibilizer can be prepared via two different method such as direct melt blending and solution. Apart from this, the TPE blend is produced via the melt blending technique with mixing machines such as internal mixer and extruder. This article has reviewed the preparation of the graft compatibilizer and blending technique of TPE. Based on the findings, the graft compatibilizers has a significant role in improving miscibility and compatibility across blend composed of different phase

Potential of industrial By-Products based geopolymer for rigid concrete pavement application

Rigid pavements are less expensive than flexible pavements and have a 20-year service life, making them more suitable for areas with weak subgrade soil and poor drainage. However, the use of rigid pavements comes at the expense of the environment. The production of cement has caused serious environmental problems, the most serious of which is the emission of carbon dioxide gas (CO2) into the atmosphere, causing natural greenhouse effect and global warming. Sustainable materials aid in the reduction of CO2 emissions as well as the use of natural raw materials in cement production. In the past few decades, significant progress has been made to develop alternative sustainable building materials (such as geopolymer cement/concrete) in order to control CO2 emissions. Numerous studies have found that geopolymer is comparable to ordinary Portland cement (OPC) in terms of strength and chemical resistance. However, only a few studies have been done on the usage of geopolymer as a rigid pavement. From the review that has been done, it can be concluded that, in addition to high strength, the requirements for rigid pavement concrete material should include fast setting time, good workability and high durability. The review emphasized that geopolymers have been proven to have excellent strength, durability and processability which fulfil the requirement for rigid pavement application. Finally, this review also introduces future research opportunities regarding the potential of geopolymers as an alternative to OPC for rigid pavements

Strength and Durability of Sustainable Self-Consolidating Concrete with High Levels of Supplementary Cementitious Materials

Self-consolidating concrete (SCC) has been used extensively in the construction industry because of its advanced characteristics of a highly flowable mixture and the ability to be consolidated under its own weight. One of the main challenges is the high content of OPC used in the production process. This research focuses on developing sustainable, high-strength self-consolidating concrete (SCC) by incorporating high levels of supplementary cementitious materials. The overarching purpose of this study is to replace OPC partially by up to 71% by using fly ash, GGBS, and microsilica to produce high-strength and durable SCC. Two groups of mixtures were designed to replace OPC. The first group contained 14%, 23.4%, and 32.77% fly ash and 6.4% microsilica. The second group contained 32.77%, 46.81%, and 65.5% GGBS and 6.4% microsilica. The fresh properties were investigated using the slump, V-funnel, L-box, and J-ring tests. The hardened properties were assessed using a compressive strength test, while water permeability, water absorption, and rapid chloride penetration tests were used to evaluate the durability. The innovation of this experimental work was introducing SCC with an unconventional mixture that can achieve highly durable and high-strength concrete. The results showed the feasibility of SCC by incorporating high volumes of fly ash and GGBS without compromising compressive strength and durability

A review on the potential of polylactic acid based thermoplastic elastomer as filament material for fused deposition modelling

Currently, a range of sectors are implementing three-dimensional (3D) printing, which is a part of additive manufacturing (AM) technology via the fused deposition modelling (FDM) approach. As of now, various filament materials are available in the market and have their limitations. Thermoplastic elastomer (TPE) blend as a filament material in 3D printing should be implemented to overcome the weakness of available filaments. TPE blend stands out due to its flexibility, thermoplastic-like processability, and renewability. Based on the findings, TPE blend filament can be made with polylactic acid (PLA) thermoplastic and elastomers such as natural rubber (NR) and epoxidized natural rubber (ENR). The TPE printed components will be flexible; tough with excellent thermal and mechanical properties. In this paper, the characteristics of TPE are being reviewed to show the potential of TPE material as filament