A master-slave generalized predictive synchronization control for preheating process of multi-cavity hot runner system

As a key component of injection molding,multi-cavity hot runner(MCHR)system faces the crucial problem of polymer melt filling imbalance among the cavities.The thermal imbalance in the system has been considered as the leading cause.Hence,the solution may rest with the synchronization of those heating processes in MCHR system.This paper proposes a’Master-Slave’generalized predictive synchronization control(MS-GPSC)method with’Mr.Slowest’strategy for preheating stage of MCHR system.The core of the proposed method is choosing the heating process with slowest dynamics as the’Master’to track the setpoint,while the other heating processes are treated as‘Slaves’tracking the output of’Master’.This proposed method is shown to have the good ability of temperature synchronization.The corresponding analysis is conducted on parameters tuning and stability,simulations and experiments show the strategy is effective.

Application of Fuzzy Control to Improve Flow Balance of Multi-Cavity Hot Runner System

In this study, we propose a new temperature compensation control strategy for a multi-cavity hot runner injection molding system, At first, the melt filling time of each cavity can be measured by installing temperature sensors on the position around end filling area, and filling time difference between the various cavities can be calculated. Then the melt temperature of each hot nozzle can be adjusted automatically by a control strategy established based on the Fuzzy Theory and a program compiled with LABVIEW software. Temperature changes the melt mobility, so the adjustment of temperature can equalize the filling time of the melt in each cavity, which can reduced the mass deviation between each cavity and make product properties of each cavity consistent. The conclusion of the experiment is as follows： For this contact lens box of a four-cavity Hot Runner mold, by applying hot runner temperature compensation control system, time difference can be reduced from 0.05 s to 0.01 s at each cavity, and the mass Standard deviation of the four cavity can be improved from 0.006 to 0.002. The ratio of imbalance can be reduced from 20% to 4%. Hence, the hot runner temperature compensation control system has significant feasibility and high potential in improving melt flow balance of multi-cavity molding application.

Protection of entanglement between two V-atoms in a multi-cavity coupling system

The protection of the entanglement between two V-atoms(EBTVA)in a multi-cavity coupling system is studied.The whole system consists of two V-atoms.The two V-atoms are initially in the maximum entangled state and interacts locally with its own dissipative cavity which is coupled to the external cavities with high quality factor(ECWHQF).The results show that,when there is no ECWHQF,the EBTVA can be protected effectively in the case where the V-atom and the dissipative cavity are weak coupled in large detuning,while when there are different numbers n of ECWHQF coupled to two dissipative cavities,by adjusting the parameters of the number n of ECWHQF and the coupling strength k between cavities,the EBTVA can be protected perfectly and continuously.Our result provides an effective method for protecting entanglement resources of three-level system.

A novel multi-cavity Helmholtz muffler

A novel multi-cavity Helmholtz muffler is proposed. The multi-cavity Helmholtz muffler is composed of steel structures and silicone membranes. With suitable construction, the Helmholtz muffler can be designed to exhibit negative mass density in low frequency, and the muffling frequency can be adjusted when we change the internal structure of the cavity,which will be very attractive for noise control. In this paper, we investigate the influence of the membranes and the cavities on noise reduction characteristics with theoretical calculations and simulations. The results show that the numbers of membranes and the volumes of the cavities can have a great effect on the position of the muffling frequency. The number of cavities can have a great effect on the width of the muffling frequency(reduce the noise by 10 dB). With different combinations of the membranes and cavities, we can get different muffling frequencies, which can meet different muffling demands in practical applications and is more flexible than the traditional Helmholtz cavity.

Selection of the Optimal Cooling Parameters to the Multi-Cavity Die

This study is subject to the finite element and abd uc tive network method application in the multi-cavity die. In order to select the optimal cooling system parameters to minimize the warp of a die-casting die, t he Taguchi’s method and the abductive network are used. These methods are appli ed to create an efficient model with functional nodes for the considered problem . Once the cooling system parameters are developed, this network can be used to predict the warp for the die-casting die accurately. A simulated annealing (SA) optimization algorithm with a performance index is then applied to the neur al network for searching the optimal cooling system parameters, and obtain rathe r satisfactory result as compared with the corresponding finite element veri fication.

基于CAE技术的拖拉机进气管注塑模具设计

以拖拉机进气管注塑模具为研究对象,探讨了基于CAE技术的拖拉机进气管注塑模具设计方法。首先,对拖拉机进气管塑件结构和工艺性进行了深入分析;然后,详细介绍了CAE技术在拖拉机进气管塑件中的辅助设计功能;最后,针对模具浇注系统、推出机构、冷却系统、模架结构和模具结构等方面,进行了拖拉机进气管注塑模具的设计,大大提高了模具的成型效果和生产效率,避免设计过程中的试错和重复设计,节省了时间和成本。

农业拖拉机尾灯多色注塑模具设计

以农业拖拉机尾灯为研究对象,分析了尾灯的内部结构和工艺性,并针对双色模具的特殊性,分析了模具成型方案和设计流程,基于AutoCAD和CAE软件完成了尾灯双色塑件模具的设计。开模试验表明:该产品符合设计需求,整个产品结构稳定,透明度好,设计的模具结构合理、工艺流程可靠,能够满足实际的生产应用,工程应用价值较高。

Microstructure and mechanical properties of Mg-Gd-Y-Zr alloy cast by metal mould and lost foam casting

The microstructure and mechanical properties of Mg-10.1Gd-3.74Y-0.25Zr （mass fraction, %） alloy （GW104 alloy） cast by metal mould casting （MMC） and lost foam casting （LFC） were evaluated, respectively. It is revealed that different forming modes do not influence the phase composition of as-cast alloy. In the as-cast specimens, the microstructures are similar and composed of α-Mg solid solution, eutectic compound of α-Mg＋Mg 24 （Gd, Y） 5 and cuboid-shaped Mg 5 （Gd, Y） phase; whereas the average grain size of the alloy produced by metal mould casting is smaller than that by lost foam casting. The eutectic compound of the alloy is completely dissolved after solution treatment at 525 ℃for 6 h, while the Mg 5 （Gd, Y） phase still exists after solution treatment. After peak-ageing, the lost foam cast alloy exhibits the maximum ultimate tensile strength of 285 MPa, and metal mould cast specimen 325 MPa at room temperature, while the tensile yield strengths of them are comparable. It can be concluded that GW104 alloy cast by lost foam casting possesses similar microstructure and evidently lower mechanical strength compared with metal mould cast alloy, due to slow solidification rate and proneness to form shrinkage porosities during lost foam casting process.

Production of carbon anodes by high-temperature mould pressing

Laboratory-scale carbon anodes were produced by a new method of high temperature mould pressing, and their physico-chemical properties were studied. The influence of mould pressing conditions and coal pitch addition on the bulk density, crushing strength, and oxidation resistance was analyzed. The mierostructure of carbon anodes was investigated by scanning electron microscopy （SEM）, and the mechanism of producing carbon anodes by high-temperature mould pressing was analyzed. The results show that when the anodes are produced by high-temperature mould pressing, coal pitch can expand into the coke particles and fill the pores inside the particles, which is beneficial for improving the quality of prebaked anodes. The bulk density of carbon anodes is 1.64-1.66 g/cm3, which is 0.08-0.12 g/cm3 higher than that of industrial anodes, and the oxidation resistance of carbon anodes is also significantly improved.

不同状态鲜核桃冷藏期间品质变化的差异

为探讨不同状态鲜核桃贮藏期间种仁的品质变化差异,以‘清香’鲜核桃为材料,测定3种状态鲜核桃(带壳坚果、整仁和碎仁)在(0±0.5)℃冷藏期间的品质指标动态变化。结果表明,贮藏期间各状态鲜核桃的发霉指数随着贮藏时间的延长而升高,整仁和碎仁的发霉指数显著降低;脂肪酸组分无显著变化,不饱和脂肪酸含量下降,饱和脂肪酸含量上升;3种状态的粗脂肪含量总体下降,以碎仁的粗脂肪平均含量最高,其在贮藏30 d期间多酚氧化酶活性较低,过氧化物酶活性显著升高,之后其可溶性糖和可溶性蛋白质含量却低于坚果和整仁;酸价和过氧化值均符合林业标准。总体上看,贮藏过程中整仁保持了较好的品质,碎仁油脂品质相对稳定,但因其破碎程度高,营养成分含量损失较多较早失去商品价值,而坚果在保持较高的营养方面具有更大潜力。

Study on Blade Mould CAD/CAM for Hydrodynamic Torque COnverters

Aim To develop blade mould CAD/CAM system of torque converter. Methods The mouldconsisted of four parts and an interactive computer program was developed to design a blade mould of torque converter based on UG at workstation. Results As compar- ed to manual modeling, it is showed in the application that this means not only improves the accuracy of blade shape and manufacture efficiency of converter, but also reduces costs. Conclusion It is proved that this CAD/CAM system is successful, and it opens up widely prospects for design and manufacture of the blade elementsand their moulds.

汽车中控箱座双料双射成型注射模设计

双射成型模具设计中,关键难点在于第一射和第二射子模具模腔的更换设计。针对汽车中控箱座塑件双射成型的需要,设计了一副两板式一模两腔布局热流道双料双射成型模具。双射模具中为克服双射模具设计中型腔更换设计困难的问题,采用换腔不换芯的设计方法,在两副子模具动模结构设计相同的情形下,将定模中型腔的换腔方式设计为斜顶块换腔方式进行第二射型腔的更换,有效避免了在动模一侧采用滑块机构实施型腔更换带来的模具结构复杂性,有效简化了模具结构,降低了模具制造成本。斜顶块换腔方式使用了3种类型的斜顶机构,分别为斜导柱增强驱动型单斜顶杆下坡抽芯斜顶杆机构、单斜顶杆下坡抽芯斜顶杆机构、水平抽芯斜顶杆机构。下坡斜顶机构用于塑件侧边的斜向抽芯脱模,下坡斜顶机构斜顶座中的下坡滑块下坡滑动角与塑件中的斜角相同,都为5°。双射模具的第一射、第二射子模具的顶出机构分别采用独立的油缸驱动机构进行驱动,使双射模具的结构设计更为灵活方便,简化模具整体结构。

健身手圈工业设计与子零件模内注塑组装模具设计

健身手圈产品注射成型生产中,需要在已成型球圈子零件的基础上,再通过注塑法成型2个独立的塑料环体子零件。针对这一成型难题,设计了一副三板模具实现健身手圈独立塑料环体的自动化注塑生产。模具中,首先使用二级点浇口流道浇注系统解决了多个健身手圈产品多腔同步生产和单腔内多个子零件同步独立注射成型的难点。其次,采用分区设置成型件和成型件集成驱动的方法实现了单腔内2个子零件注射成型后的自动脱模。分区成型件设计中,以球圈子零件中心环线为界,结合脱模的需要,将单腔成型件分为6个成型件;其中,中心环线外侧的2个成型件设置为侧滑块机构用于侧抽芯脱模,1个成型件设置为延时滑块机构用于侧抽芯强制脱模;中心环线内侧的3个成型件设置为一个复合斜顶机构,用于内侧狭小区域的3向联动同步抽芯脱模。模具分3次开模,较好地实现了流道废料、环体塑件的自动脱模及2个环体塑件在球圈子零件上的注塑组装,为该类产品的工业设计提供了新的产品工业设计方法选择。

一种蜗壳类产品三维铸造工艺的绘制方法

蜗壳类产品是典型的曲面结构模型,为了方便模具起型,制定铸造工艺方案时就要考虑分型、分芯的方法。分型、分芯位置决定了砂芯数量和模具工艺的复杂性。本文所述一种蜗壳类产品三维铸造工艺的绘制方法,从加工面、补贴到分型等问题细节性的讲述绘制过程。

模具局部激光熔覆耐磨涂层研究及应用

注塑模具流道出口工况苛刻,极易发生磨损,导致其形状和尺寸发生变化,对产品的质量和生产效率造成较大影响。基于此,本研究采用激光熔覆技术对注塑模具流道出口进行局部强化,针对强化涂层材料成分的设计、熔覆成形和缺陷控制、组织性能分析、实际工件加工工艺调控等开展研究。结果表明:相比商用耐磨涂层材料,所开发的涂层材料具备优异的熔覆成形和无裂纹缺陷,硬度由强化前基体硬度400HV提升至900HV以上,涂层耐磨性能相对基体提升43倍,摩擦系数由基体的0.635降至0.412,极大改善了模具的耐磨性能;强化涂层内部晶粒细小,主要由马氏体和原位陶瓷碳化物保障其耐磨性,并残留少量奥氏体保障其韧性;通过特殊的路径规划和工艺控制,在注塑模具局部强化中得到成功应用,强化后模具的服役寿命提升3倍以上。

Solvent de binding of water soluble binder in powder injection moulding

The solvent debinding of water soluble binder in powder injection moulding (MIM) was investigated systematically, including the effects of solvent types, temperature and the thickness of green parts on the solvent debinding rate. After studying the debinding of a green part with a thickness of 4.26 mm, it was found that, the debinding rate of polyethylene glycol(PEG) in water and alcohol was high initially, and then decreased; however, it would increase with temperature increasing. At room temperature, the dissolution rate of PEG in water was higher than that in alcohol, but the latter would be much faster with temperature increasing because the debinding activation energy in alcohol was 51.44 kJ·mol -1 ·K -1 , much higher than 24.23 kJ·mol -1 ·K -1 in water. With a green part thickness larger than 4.26 mm, the debinding was controlled by diffusion; but with that smaller than 2.36 mm, the debinding was controlled by both dissolution and diffusion.

Development tendencies of moulding and core sands

Further development of the technology for making moulding and core sands will be strictly limited by tough requirements due to protection of the natural environment. These tendencies are becoming more and more tense, so that we will reach a point when even processes, that from technological point of view fulfill high requirements of the foundry industry, must be replaced by more ecologically-friendly solutions. Hence, technologies using synthetic resins as binding materials will be limited. This paper presents some predictable development tendencies of moulding and core sands. The increasing role of inorganic substances will be noticed, including silicate binders with significantly improved properties, such as improved knock-out property or higher reclamation strength. Other interesting solutions might also be moulding sands bonded by geo-polymers and phosphate binders or salts and also binders based on degradable biopolymers. These tendencies and the usefulness of these binders are put forward in this paper.

Experimental study on cracking behaviour of moulded gypsum containing two non-parallel overlapping flaws under uniaxial compression

Failure of rock mass that is subjected to compressive loads occurs from initiation, propagation, and linkage of new cracks from preexisting fissures. Our research investigates the cracking behaviour and coalescence process in a brittle material with two non-parallel overlapping flaws using a high-speed camera. The coalescence tensile crack and tensile wing cracks were the first cracks to occur from the preexisting flaws. The initiation stresses of the primary cracks at the two tips of each flaw were simultaneous and decreased with reduced flaw inclination angle. The following types of coalescence cracks were identified between the flaws: primary tensile coalescence crack, tensile crack linkage, shear crack linkage, mixed tensile-shear crack, and indirect crack coalescence. Coalescence through tensile linkage occurred mostly at pre-peak stress. In contrast, coalescence through shear or mixed tensile-shear cracks occurred at higher stress. Overall, this study indicates that the geometry of preexisting flaws affect crack initiation and coalescence behaviour.

Effect of Traveling Magnetic Field on Mould-Filling Length of the A357 Melt during Casting Thin Walled Plate

In order to improve the mould filling ability, the method for production of thin-walled castings in the travelingmagnetic field was applied. The relationship between magnetic field density and input voltage as well as distancewas investigated, and the mould filling length of A357 melt has been studied. The electromagnetic forces appliedon the melt were also analyzed. The result shows that the mould-filling length of the melt increase rapidly with theincrease of magnetic flux density. The mould filling lengths in gypsum upper mould and magnetic material uppermould were compared from the standpoint of application. It demonstrated that the steel upper mould is superior togypsum mould.