基于 Moldflow 的汽车中控台框架翘曲变形分析及优化

以某汽车中控台框架为研究对象,测量试模样品发现其翘曲变形量超过了装配要求。通过Moldflow软件模拟了该塑件实际的注塑过程,翘曲变形量的模拟值与实测平均值的最大误差为5.98%,发现该塑件翘曲变形的主要因素为冷却不均和收缩不均。本文在原物料中添加质量分数为25%的玻璃纤维以及优化工艺参数后,翘曲变形量的模拟值与初始方案相比降低了86.22%。试模验证表明,优化后的翘曲变形量模拟值与实测平均值的最大误差为4.35%,证明了Moldflow软件模拟分析的准确性。试模后各检测点的最大翘曲变形量降到了1.6 mm以下,较优化之前降低了80%以上,为类似大型复杂注塑件的翘曲变形分析及优化提供了思路。

Management of Strawberry Grey Mold Disease Using Biocontrol Agents and Plant Extracts

Strawberry (Fragaria × ananassa Duch.) is a significant global soft fruit crop, prized for its nutrient content and pleasant flavor. However, diseases, particularly grey mold caused by Botrytis cinerea Pers. Fr. poses major constraints to strawberry production and productivity. Grey mold severely impacts fruit quality and quantity, diminishing market value. This study evaluated five B. cinerea isolates from various locations in the Ri-Bhoi district of Meghalaya. All isolates were pathogenic, with isolate SGM 2 identified as highly virulent. Host range studies showed the pathogen-producing symptoms in the fava bean pods, marigold, gerbera, and chrysanthemum flowers and in the fava bean, gerbera, and lettuce leaves. In vitro tests revealed that neem extract (15% w/v) achieved the highest mycelial growth inhibition at 76.66%, while black turmeric extract (5% w/v) had the lowest inhibition at 9.62%. Dual culture methods with bio-control agents indicated that Bacillus subtilis recorded the highest mean inhibition at 77.03%, while Pseudomonas fluorescens had the lowest at 20.36% against the two virulent isolates. Pot evaluations demonstrated that B. subtilis resulted in the lowest percent disease index at 20.59%, followed by neem extract at 23.31%, with the highest disease index in the control group at 42.51%. Additionally, B. subtilis significantly improved plant growth, yielding an average of 0.32 kg compared to 0.14 kg in the control. The promising results of B. subtilis and neem leaf extract from this study suggest their potential for eco-friendly managing grey mold in strawberries under field conditions.

Non-Darcy Flow in Molding Sands

Darcy’s law is widely used to describe the flow in porous media in which there is a linear relationship between fluid velocity and pressure gradient. However, it has been found that for high numbers of Reynolds this law ceases to be valid. In this work, the Ergun equation is employed to consider the non-linearity of air velocity with the pressure gradient in casting sands. The contribution of non-linearity to the total flow in terms of a variable defined as a non-Darcy flow fraction is numerically quantified. In addition, the influence of the shape factor of the sand grains on the non-linear flow fraction is analyzed. It is found that for values of the Reynolds number less or equal than 1, the contribution of non-linearity for spherical particles is around 1.15%.

Determination of Optimal Manufacturing Parameters for Injection Mold by Inverse Model Basing on MANFIS

Since plastic products are with the features as light, anticorrosive and low cost etc., that are generally used in several of tools or components. Consequently, the requirements on the quality and effectiveness in production are increasingly serious. However, there are many factors affecting the yield rate of injection products such as material characteristic, mold design, and manufacturing parameters etc. involved with injection machine and the whole manufacturing process. Traditionally, these factors can only be designed and adjusted by many times of trial-and-error tests. It is not only waste of time and resource, but also lack of methodology for referring. Although there are some methods as Taguchi method or neural network etc. proposed for serving and optimizing this problem, they are still insufficient for the needs. For the reasons, a method for determining the optimal parameters by the inverse model of manufacturing platform is proposed in this paper. Through the integration of inverse model basing on MANFIS and Taguchi method, inversely, the optimal manufacturing parameters can be found by using the product requirements. The effectiveness and feasibility of this proposal is confirmed through numerical studies on a real case example.

Effect of CeO_2 on heat transfer and crystallization behavior of rare earth alloy steel mold fluxes

To improve the heat transfer capability and the crystallization property of the traditional mold flux, CaF_2 was replaced with B_2O_3. Then, the influences of CeO_2 on the heat transfer and the crystallization of the CaF_2-bearing mold flux and the new mold flux with 10 wt% B_2O_3 were studied using a slag film heat flux simulator and X-ray diffraction(XRD). The results revealed that the addition of CeO2 reduced the heat transfer by increasing the solid slag thickness and the crystallization of two mold fluxes. However, CeO_2 had less effect on the B_2O_3-containing mold flux compared with the CaF_2-bearing mold flux. According to the analyses, the CeO_2 contents in the CaF_2-bearing mold flux and the B_2O_3-containing mold flux should not exceed 8 wt% and 12 wt%, respectively. Therefore, these experimental results are beneficial to improve and develop the mold flux for casting rare earth alloy steels.

Interfacial microstructure and mechanical properties of Ti-6Al-4V/Al7050 joints fabricated using the insert molding method

Ti-6Al-4V/Al7050 joints were fabricated by a method of insert molding and corresponding interfacial microstructure and mechanical properties were investigated. The interfacial thickness was sensitive to holding temperature during the first stage, and a good metallurgical bonding interface with a thickness of about 90 μm can be obtained at 750°C. X-ray diffraction, transmission electron microscopy, and thermodynamic analyses showed that the interface mainly contained intermetallic compound TiAl_3 and Al matrix. The joints featured good mechanical properties, i.e., shear strength of 154 MPa, tensile strength of 215 MPa, and compressive strength of 283 MPa, which are superior to those of joints fabricated by other methods. Coherent boundaries between Al/TiAl_3 and TiAl_3/Ti were confirmed to contribute to outstanding interfacial mechanical properties and also explained constant fracture occurrence in the Al matrix. Follow-up studies should focus on improving mechanical properties of the Al matrix by deformation and heat treatment.

Parameter Prediction of Stretch-Blow Molding Process of PET Using Neural Networks

This study presents a parameter selection strategy developed for the Stretch-Blow Molding (SBM) process to minimize the weight of preforms used. The method is based on a predictive model developed using Neural Networks. The temperature distribution model of the preform was predicted using a 3-layer NN model with supervised backpropagation learning. In addition, the model was used to predict the uniform air pressure applied inside the preform, taking into account the relationship between the internal air pressure and the volume of the preform. Parameters were validated using in situ tests and measurements performed on several weights and lengths of a 0.330 Liter Polyethylene Terephthalate (PET) bottles. Tests showed that the model adequately predicts both the blowing kinematics, mainly zone temperatures and blowing and stretching pressures along the walls of the bottle while maintaining the bottle strength and top load requirements. In the second step, the model was combined to automatically compute the lowest preform weight that can be used for a particular 330 ml bottle design providing a uniform wall thickness distribution.

Production and Testing of Biopesticide for Control of Postharvest Mold Infections on Fresh Fruits of Apple and Pear

The present research aimed at producing a biopesticide with proper formulation of invert emulsion (water-in-oil type) and effective strain of?Trichoderma harzianum?then, testing it against pathogens of postharvest mold infections(Botrytis cinerea?&?Penicillium expansum) on fresh fruits of apple and pear. The?proper formulation of invert emulsion (IE#3) used for biopesticide production has the following ingredients (100% w/w): soybean oil (28.50%), coconut oil (19.50%), oil-soluble emulsifier: Tween 20 (2.0%), glycerine (4.25%), water-soluble emulsifier:?dehymuls k (0.75%),?sterile distilled water (22.5%) and conidial suspension of the effective strain ofT. harzianum?“TrichoPAL1” in water (22.5%, concentration 1 ×?107?conidia/ml). Testing efficacy of the produced biopesticide has indicated a significant reduction in the disease lesion diameter of mold infections on wounded apple and pear fruits stored at?20℃?± 1℃?compared to the untreated fruits or control (reduction from up to 38.75 to about 7.50 mm, respectively, according to?the type of mold infections and fruit type). Also, the treatment with the produced biopesticide has resulted in?a long protection period from mold infections on wounded and un-wounded fresh fruits of apple and pear stored under controlled and semi-commercial conditions(up to 2.5 months according to the type of mold infections and fruit type). In conclusion, the overall results have demonstrated the effectiveness of produced biopesticide on stored fruits under controlled and semi-commercial conditions therefore,?it is recommended to test this effectiveness on marketed fruits stored under variable conditions before applying it at a large scale.

Kansei Engineering Applied to the Form Design of Injection Molding Machines

This study investigated the relationship between a subject’s evaluation of injection molding machines (IMMs) and formal design features using Kansei engineering. This investigation used 12 word pairs to evaluate the IMM configurations and employed the semantic differential method to explore the perception of 60 interviewees of 12 examples. The relationship between product feature design and corresponding words was derived by multiple regression analysis. Factor analysis reveals that the 12 examples can be categorized as two styles—advanced style and succinct style. For the advanced style, an IMM should use a rectangular form for the clamping-unit cover and a full-cover for the injection-unit. For the succinct style, the IMM configuration should use a beveled form for the safety cover and a vertical rectangular form for the clamping-unit cover. Quantitative data and suggested guidelines for the relationship between design features and interviewee evaluations are useful to product designers when formulating design strategies.

Reaction of Sorghum Differentials to Grain Mold Infection in Puerto Rico

Grain mold, associated with many fungi, is the most important disease of sorghum, causing both yield and quality losses. In this study, 23 sorghum differentials used in pathotype characterization of anthracnose and head smut pathogens were evaluated for grain mold resistance under favorable conditions in Isabela, Puerto Rico. Lines BTx643 and IS18760 exhibited the lowest grain mold severity, indicating that these two may possess genes for grain mold resistance. These two lines also recorded the highest germination rates 94.7% and 97.6%, respectively, and their seed weight was among the heaviest. In conclusion, these two lines can be utilized in breeding programs to develop grain mold-resistant hybrid lines.

Effect of sintering parameters on powder injection molded Ti(C, N)-based cermets

Effect of two-stage sintering parameters such as heating rate, top sintering temperature and holding time, sintering temperature and holding time at the second stage on relative density, transverse rupture strength(TRS) and microstructures of powder injection molded Ti(C, N)-based cermets were investigated, by means of Archimedes’s method, three-point bending test and micrographic analysis. The results show that the optimum sintering cycle for powder injection molded Ti(C, N)-based cermets comprises rapid heating (10℃/min) at low temperatures, slow heating (5℃/min) at intermediate temperatures, holding at the highest sintering temperature (1420℃) for a short time (10min), and holding at the second stage (1360℃) for a longer time (6h) to avoid grain coarsening, and that its TRS reaches 624MPa, and there are little pores in their microstructures.

Molten steel level stability in continuous casting slab mold under electromagnetic stirring

Fluctuation of molten steel level in continuous casting process is a critical issue. The analytic function for the liquid steel surface stability index( F) of the continuous casting slab mold under the action of electromagnetic stirring was derived. The effects on the F value of the electromagnetic field,casting mold,submerged entry nozzle,and casting speed were observed,and the stability of the process parameters of a practical continuous casting system was evaluated. The main results generated are as follows:①Based on the free flow jet theory,a formula is established for the level stability index of continuous casting slab mold under electromagnetic stirring.②According to the results of calculation,the various parameters in decreasing order of the magnitude of their influence are magnetic flux density,nozzle submersion depth,casting speed,slab width,stirring current frequency,and nozzle side-hole inclination angle.③For practical continuous casting with a slab thickness of 230 mm,the calculated F values are between 3 and 5 for different matches between slab width and casting speed,but the parameter optimization space is much larger for wider slab widths and lower casting speeds.

Withdraw: Improvement on Adhesion Properties of Insert Injection Molding Composites: Effect of Inserted Parts, Adhesive Lengths and Injection Conditions

Short Retraction Notice The paper does not meet the standards of "Open Journal of Composite Materials". This article has been retracted to straighten the academic record. In making this decision the Editorial Board follows COPE's Retraction Guidelines. The aim is to promote the circulation of scientific research by offering an ideal research publication platform with due consideration of internationally accepted standards on publication ethics. The Editorial Board would like to extend its sincere apologies for any inconvenience this retraction may have caused. Editor guiding this retraction: Prof. Chengye Fan (EiC of OJCM) The full retraction notice in PDF is preceding the original paper, which is marked "Withdraw".

Comparison of rheological analytic model with numerical simulation in powder injection molding filling process

Mathematical model of filling disk-shaped mold cavity in steady state was studied.And the mathematical model under vibration field was developed from the model in steady state.According to the model of filling disk-shaped mold cavity in steady state,the filling time,the distribution of velocity field and the pressure field were obtained.The analysis results from rheological analytic model were compared with the numerical simulation results using Moldflow software in the powder injection molding filling process.Through the comparison,it is found that it is unreasonable to neglect the influence of temperature when calculated the pressure changing with the time at the cavity gate,while it can be neglected in other situations such as calculating the distribution of the velocity fields.This provides a theoretical reference for the establishment of correct model both in steady state and under vibration force field in the future.

Exploring the Potential to Uniquely Manufacture Curved VARTM Epoxy Composites Using Cost-Effective FDM Molds

The Resin Infusion or the VARTM (Vacuum Assisted Resin Transfer Molding) process has significant potential to be used to manufacture curved composites. Another way to produce curved or complex geometry is to use 3D printers. 3D or FDM (Fused Deposition Modelling) printers are now being used to produce relatively cheaper curved parts using thermoplastics such as PLA. However, the strength and mechanical performance of these parts is limited and can be enhanced if the polymer is reinforced with a type of fiber for instance. Research is being carried out to produce fiber rein-forced thermoplastic composites but that process is expected to be more expensive than the alternative methods such as injection or compression molding. Furthermore, to understand the manufacture of a hybrid composite using thermoplastics, fibers and epoxy resin, research and investigation need to be carried out. In this research, there are single-sided, double-sided, reusable, disposable and consumable molds. Most of the molds were created either using an FDM printer or manually. These molds were then used to manufacture flat and curved composite structures via the resin injection process, i.e. VARTM with epoxy resin system and glass/carbon/flax fiber reinforcement. By replacing the costly metallic molds by significantly cheaper molds, the cost of production was expected to further reduce. Furthermore, using double-sided PLA molds was not expected to be a threat to the overall cost of the composite part in question compared to double-sided matched molds used in compression molding. Shear strength, tensile strength and charpy impact strength of most of the manufactured composite parts were also investigated. The strengths were compared based on the method of mold usage. The results showed that this method is effective for a cheaper production of curved epoxy resin composites. However, the strength of the part will decrease as the curved profile gets more complicated unless the basic resin infusion process is altered.

Microstructure of coupled Al/gray cast iron obtained by molding and its effect on mass loss

This study aims to consolidate the surface of gray cast iron with aluminum deposition by developing a method that combines the preparation and surface treatment in a single operation. The effect of the wall thickness of the castings on the microstructure of the formed layers was studied, and two thicknesses, 8 mm and 25 mm, were studied. The formation of a continuous and homogeneous rich aluminum layer on the surface of the cast iron was observed. The formed layer is composed of two successive zones identified as two proeutectoid phases FeAl+FeAl/FeAl2 and single-phase FeAl, which significantly increases the surface hardness. Furthermore, this change in surface composition makes it possible to reduce the mass of the immersed samples in a 1 M hydrochloric acid solution during different exposure times(1 to 4 days). Consequently, a clear improvement in the corrosion resistance of the treated layers is highlighted.

Genetic Analysis of Resistance to Tomato Gray Mold( Botrytis cinerea)

The study used four tomato varieties,03786( susceptible),05237( susceptible),C2985( resistant) and Wva536( resistant) with different resistance,to formulate combinations according to Griffing( I) complete diallel cross method. And Botrytis cinerea was inoculated to investigate the incidence of gray mold. The results showed that:(1) there were significant differences in disease resistance between different varieties and different combinations.(2) There were significant differences in general combining ability and special combining ability between the tested varieties,and Wva536 and C2985 had a higher general combining ability effect,and were both relatively good parents when formulating resistant combinations. Combinations Wva536 × 03786 and Wva536 × 05237 had the highest special combining ability,and thus have the value of further research and utilization.(3) The additive effect in resistance inheritance was located at the primary position,and partial dominance also existed as well as cytoplasmic effect.(4) The broad-sense heritability and narrow-sense heritability were,respectively,89. 73% and82. 15%,which were higher,indicating that the parents had a greater effect on offsprings. The resistance genes can be expressed in offsprings through gene accumulation,and should be selected in the early generation.

Controlled cooling of an aluminum alloy casting based on 3D printed rib reinforced shell mold

3D printing technology has been used for sand molding and core printing, but they simply substitute the traditional molding and core making method without changing the shape or size of the sand mold(core) and their dense structure. In this study, a new type of hollow mold based on 3D printing is presented. The new type of mold is a rib reinforced thickness-varying shell mold. This mold design can realize the controlled cooling of castings, i.e., different cooling rates at different areas, and improve the temperature uniformity of a casting after its solidifi cation. Therefore, the performance of castings can be improved and their residual stress and deformation can be reduced. This kind of new mold was applied to a stress frame of A356 aluminum alloy. The 3D printed rib reinforced thickness-varying shell mold was compared with the traditional dense mold, and the castings obtained by these two kinds of molds were also compared. The experimental results showed that the rib reinforced shell mold increased the cooling rate of the casting by 30%, tensile strength by 17%, yield strength by 11%, elongation by 67%, and decreased its deformation by 43%, while sand consumption was greatly reduced by 90%.

A Qualitative Study of the Influence of Grooved Mold Surface Topography on the Formation of Surface Marks on As-Cast Ingots of Aluminum Alloy 3003

The effects of the wavelength and orientation of machined grooves on a mold surface, casting speed, and melt superheat on the formation of surface marks on as-cast ingots were studied with an immersion casting tester and copper mold chill blocks. The mold surface topographies included a polished smooth surface, and those with machined unidirectional parallel contoured grooves oriented either parallel (vertical) or perpendicular (horizontal) to the casting direction. The unidirectional grooves were 0.232 mm deep with wavelength or spacing between 1 and 15 mm. The casting speed and melt superheat were between 1 and 200 mm/s, and 10 and 50 K, respectively. Two primary types of surface marks were observed on ingots cast with the copper mold with smooth surface topography, namely the finer and closely spaced ripples (Type I), and the widely spaced but coarser laps (Type II). The latter were more prevalent at the higher casting speeds and melt superheats. Qualitatively, formation of both types of surface marks on the as-cast ingots of the aluminum alloy 3003 appeared to be alleviated by increase in casting speed and melt superheat, and by the use of molds with grooved surface topography. In fact, casting with a mold surface with 1 mm spaced grooves that are perpendicular to the casting direction eliminated the formation of surface marks at casting speeds greater than 1 mm/s. It also improved the uniformity of the ingot subsurface microstructure and eliminated the associated subsurface segregation.

Mechanical Properties of Carbon Epoxy Prepreg Insert Phenolic Resin Injection Moldings

This study focuses on the insert-injection molding process. The thermoset composite inserts in this study were carbon fiber/epoxy (CF/Epoxy) prepreg sheets. The injected molded part was glass fiber contained phenolic resin (GF/PF). The CF/Epoxy was placed in the mold cavity prior to injecting GF/PF onto the inserted injection molded CF/Epoxy specimens. The role of adhesion between the inserted part and injected resin on the mechanical properties was evaluated by 3 point bending and impact tests. In addition, the effect of prepreg orientation on the mechanical properties of the prepreg inserted-injection molding system was investigated. It was found that the prepreg with unidirectional orientation significantly improved flexural and impact strength of the inserted injection molding composites, providing better support and resistance to bending and impact loading. The main failure modes of the specimens were structural and adhesive failure.