Study on Numerical Simulation of Mold Filling and Heat Transfer in Die Casting Process

A 3-D mathematical model considering turbulence phenomena has been established based on a computational fluid dynamics technique, so called 3-D SOLA-VOF (Solution Algorithm-Volume of Fluid), to simulate the fluid flow of mold filling process of die casting. In addition, the mathematical model for simulating the heat transfer in die casting process has also been established. The computation program has been developed by the authors with the finite difference method (FDM) recently. As verification, the mold filling process of a S-shaped die casting has been simulated and the simulation results coincide with that of the benchmark test. Finally, as a practical application, the gating design of a motorcycle component was modified by the mold filling simulation and the dies design of another motorcycle component was optimized by the heat transfer simulation. All the optimized designs were verified by the production practice.

Theoretical modeling of cutting temperature in high-speed end milling process for die/mold machining

A parametric model of cutting temperature generated in end milling process is developed according to the thermal mechanism of end milling as an intermittent operation, which periodically repeats the cycle of heating under cutting and cooling under non-cutting. It shows that cutting speed and the tool-workpiece engagement condition are determinative for tool temperature in the operation. The suggested model was investigated by tests of AlTiN coated endmill machining hardened die steel JIS SKD61, where cutting temperature on the flank face of tool was measured with an optical fiber type radiation thermometer. Experimental results show that the tendency of cutting temperature to increase with cutting speed and engagement angle is intensified with the progressing tool wear.

Simulation of mold filling and prediction of gas entrapment on practical high pressure die castings

Element parameters including volume filled ratio,surface dimensionless distance,and surface filled ratio for DFDM(direct finite difference method)were proposed to describe shape and location of free surfaces in casting mold filling processes.A mathematical model of the filling process was proposed specially considering the mass,momentum and heat transfer in the vicinity of free surfaces.Furthermore,a method for gas entrapment was established by tracking flow of entrapped gas.The model and method were applied to practical ADC1 high pressure die castings.The gas entrapment prediction was compared with the fraction and maximum size of porosities in the different casting parts.The comparison shows validity of the proposed model and method.The study indicates that final porosities in high pressure die castings are dependent on both gas entrapment during mold filling process and pressure transfer within solidification period.

Low-cycle fatigue behavior of permanent mold cast and die-cast Al-Si-Cu-Mg alloys

Fatigue failure is one of the main failure forms of Al-Si-Cu-Mg aluminum alloys.To feature their mechanical aspect of fatigue behavior,the low-cycle fatigue behavior of permanent mold cast and die-cast Al-Si-Cu-Mg alloys at room temperature was investigated.The experimental results show that both permanent mold cast and die-cast Al-Si-Cu-Mg alloys mainly exhibit cyclic strain hardening.At the same total strain amplitude,the die-cast Al-Si-Cu-Mg alloy shows higher cyclic deformation resistance and longer fatigue life than does the permanent mold cast Al-Si-Cu-Mg alloy.The relationship between both elastic and plastic strain amplitudes with reversals to failure shows a monotonic linear behavior,and can be described by the Basquin and Coffin-Manson equations,respectively.

Mold Filling and Prevention of Gas Entrapment in High-pressure Die-casting

This paper presents some results of direct observation of mold filling in a specially designed die-casting by X-ray diffraction, including comparison with numerical simulation. Based on such work the authors discuss how to prevent gas entrapment and propose new methods.

Microstructure and properties of nano-TiN modified Ti(C,N)-based cermets fabricated by powder injection molding and die pressing

Powder injection molding （PIM） and die pressing were employed to fabricate nano-TiN modified Ti（C,N）- based cermets. The shrinkage behavior, microstructure, porosity, and mechanical properties of the samples with and without nano-TiN addition fabricated by PIM and die pressing were analyzed. It is demonstrated that for either PIM or die pressing, the porosities are obviously reduced, the mechanical properties are significantly improved after adding nano-TiN, and the hard particles are refined; the rim phase thickness obviously becomes thinner, and the number of dimples in fracture also increases. Compared the samples fabricated by die pressing, it is difficult for PIM to obtain dense Ti（C,N）-based cermets. Due to the too much existence of pores and isolated carbon, the mechanical properties of the sintered samples by PIM are inferior to those of the sintered ones by die pressing.

HSM strategy study for hardened die and mold steels manufacturing based on the mechanical and thermal load reduction strategy

The paper discussed cutter-work engagement situation hidden behind the mechanical and thermal load effect on cutting edges during high speed hard machining process. The engagement situation was investigated in great detail using experimental and geometrical analytic measures. Experiments were conducted using A1TiN-coated micro-grain carbide end mill cutters to cut hardened die steel. On the basis, a general high speed hard machining strategy, which aimed at eliminating excessive engagement situation during high-speed machining （HSM） hard machining, was proposed. The strategy includes the procedures to identify prone-to-overload areas where excessive engagement situation occurs and then to create a reliable tool path, which has the effect of cutting load reduction to remove the prone-to-overload areas.

A Tool Path Re-generation Algorithm for Die & Mold Machining

Facing the challenges of a shorter product design a nd manufacturing lead-time, many mold companies are using 3-D CAD/CAM software s ystems in design and manufacturing. A new product file is often issued to the mo ld design department before it is completely finalized and the design may have t o be iterated many times during the mold design and making processes. In practic e, if a mold has been modified, all the tool paths that cover the modified regio n must be re-generated, no matter how small the modified region may be. With th e available tool path generation systems, if a tool path needs to be re-generat ed, all the cutter location (CL) points must be re-calculated, and none of the original CL points can be re-used. It would require as much time to re-gen erate the modified tool path as in the original case. On the other hand, the mod ified region is usually quite small compared with the entire mold. The complete re-generation process is therefore highly unproductive and time-consuming. This paper proposes an efficient tool path re-generation approach for 3-axis d ie and mold machining. It is assumed in this research that a gouge-free too l path has been generated for the original mold and the same ball end-mill is to be used to generate the tool path for the modified mold. It is shown in th is work that if the boundary of the modified region is interference-free, the a ffected CL points are enclosed by a set of CL points which correspond to the poi nts on the boundary of the modified region. An efficient tool path re-generatio n algorithm was developed in this research. With this algorithm, a closed CL cur ve is first generated from the boundary of the affected region. The CL points fo r the original mold are then analyzed by comparing the x and y values with the b oundary of the affected CL points. If the CL points are not affected by the modi fication, they are output to the new CL file directly. Otherwise, they are remov ed and replaced by the new CL points. The algorithm has been tested using severa l industrial parts, and results show that it is efficient, robust, and the re-g enerated tool path is gouge-free and smooth.

Focusing on Technology and Services,Competing in China Die Casting Market Report on visits with five companies participating in the Asia-pacific Die Casting Industry Exhibition 2005

The Asia-Pacific Die Casting Industry Exhibition 2005. organized by Foundry Institution of Chinese Mechanical Engineering: Society (FICMES). was held in INTEX Shanghai, China on August 14-17. 2005. On August 16th. the journalists of CHINA FOUNDRY journal visited five exhibitors on the spot of exhibition. They are: Mr. Roland FINK. General manager of Frech (Shanghai) Die Casting Machine Co. Ltd.; Mr. Thomas STROBL. General manager of Buhler Equipment Engineering (Wuxi) Co. Ltd., Switzerland; Mr. WANG Tong. Manager of ABB Engineering (Shanghai) Co. Ltd : Ms Karen LUO. National Sales Manager-Die Casting. Chem-Trend (Shanghai) Trading Co. Ltd.; and Mr. David ZHOU. Sales Supervisor of Acheson. the National Starch & Chemical (Shanghai) Company1. Interview with Mr. Rolalnd FINK, General Manager, Freeh (Shanghai) Die Casting Machine Co. Ltd., and Mr. WU Hao-sen, Representative of Shanghai Office, Freeh ChinaReporter: The die casting machines Of Oskai Freeh GmbH are famous id the world. In order to let more renders know Oskar Frech GmbH. please intrkdluce its basic conditions.Mr. FINK. Oskar Frech GmbH was founded in 1949 and now has mure than 500 employees. It is a world-famous company specialized in research of die casting technology and manufacturing complete sets of equipment. There are a considerable number of Frech's products in the world die casting industry. Especially in the field of magnesium alloy die casting. Freeh's equipment are extensively employed, occupying the large part of the market. The assorted parts are available for Frech's equipment and customers can freely choose them. Frech produces not only hot chamber die casting machines bun also cold chamber die casting machines. Freeh continues to innovate or adopt new technologies lor die casting machines. Owing to the stable and reliable performances, Frech die casting machines are not only employed for production, hut also extensively served as experimental equipment. Either Frech cold chamber die casting machines or hot chamber die casting machines have real-time control (RC)ystems for injection. In 1980. Frech far Last Ltd. was established in Hong Kong by Oskar Frech GmbH. In 1987. Shanghai Office. Frech China was set up. And in May 2005. Frech built its subsidiary factory in Shanghai, to better serve for China and the whole Asia market.Reporter: Please introduce the performances and main features of die casting machines.Mr. FINK: Frech die casting machines are classified into different series for aluminum alloys, magnesium alloys and zinc alloys, respectively. The locking forces are from 20 tons to 2 000 tons. In 1966. Frech built the first hot chamber die easting machine for magnesium in the world. Now we have more than 40 years of experiences m the manufacture of magnesium die casting machines. Frech's equipment have such advantages as high service efficiency and excellent quality. Frech continues to develop and adopt advanced technologies for the security system, die locking system, injection system. control system and hydraulic system of die casting machines. In addition, the funcktional interfaces of Frech die casting machines are complete and the entire structure designs are reasonable. Frech die easting machines have large safety coefficients, stable performancesand long service life. As far as die casting dies are concerned. Frech has kept and developed its own tool room for die manufacturing, which can help customers solvc many problems of mould design and improve the quality of die castings.Reporter: This year Frech built the production factiory. in Shanghai, and this time Frech is joining the die casting exhibition in such a largescale.It is reflected that Frech is ambitious to develop itself in the China die casting market.Mr. FINK: In the past ten years, more than 200 die casting equipment of our company have been supplied to China, Up to present, we have built the production factoryo. in Shanghai, namely frech (Shanghai) Die Casting Machine Co. Ltd. This company uses the parts and components which are all produced originally in German factories to assemble die casting machines. So the performances and qualities of die casting machines produced in Shanghai are kept unchanged, but their prices are greatly reduced, being hetter suitable for the Chinese and Asian markets. Since June this year. some hot chamber die casting machines in locking forces from 20 tons to .315 tons have been assembled in Frech (Shanghai) Die Casting Machine Co.Ltd. And we are also ready to produce cold chamber die casting machines.Then we will gradually enlarge the production scale. Another importantthing is that we are preparing in the shortest time to provide our services after sale and the desired spare parts for our customers.Interview with Mr, Roland FINK. General Manager of Frech (Shanghai) Die Casting Machine Co Ltd .and Mr.WU Hao-sen. Representattive of Shanghai Offive,Frech China.2. Interview with Mr. Thomas STROBL, General Manager of Buhler Equipment Engineering (Wuxi) Co. Ltd., SwitzerlandReporter Mr. Thomas STOBER, How many times are there for your company to participate in the die casting exhibitions organized by Foundry Institution of Chinese Mechanical Fngineering Society?How do you think of this exhibition?Mr. STROBL: Buhler has taken pan in such exhibitions for five times. Certainly, this time the investment is the largest. since this is the first time for the real Buhler machine to be displayed. The displayed machine was made in Wuxi. China. The exhibition is very good.

基于OBE理念的职教本科项目驱动式教学改革探究——以压铸模技术课程为例

依据行业发展方向,结合职业教育改革政策,从职教本科压铸模技术课程出发,以培养学生“知识+技能+创新”能力为目标,分析OBE教学理念在教学中的适用性,并从项目载体选择、项目实施、课程考核三个方面进行教学改革探索,使学生专业知识技能螺旋式提升,学习兴趣由被动变主动,创新思维得到有效锻炼,也为适应经济社会发展和技术技能的数字化设计与制造技术专业人才培养奠定基础。

应用型本科院校模具课程教学改革探索

结合应用型本科院校模具课程教学中存在的问题,进行了较为深入分析,提出了一些具体课程改革方法,可通过完善模具课程体系、引入3D打印、逆向技术、ANSYS、MoldFlow等新课程打造课程创新性,拓宽学生知识面。加大实践环节、深入校企合作、优化教学团队、改进教学方法、探索更适合模具课程教学的新模式。

职教本科背景下模具设计及制造专业课程体系的构建

明确了职教本科的人才培养定位,确定了模具专业人才培养目标,提炼了模具工艺及优化岗位、模具数字化设计岗位、模具智能化制造岗位、模具自动化生产岗位和模具信息化管理岗位等岗位所需的核心职业能力和职业素养,按照职业岗位能力和职业素养的需求设置相关课程内容,完成了职教本科背景下模具专业课程体系的构建。

基于混合式教学《模具测绘技术》课程思政的研究与实践

介绍了高职模具设计与制造专业基础课程《模具测绘技术》课程思政的教学设计与实施过程。为培养德技双修,全面发展的高素质应用型人才,从行业规范、课程标准和职业能力需求出发,制定知识学习线、技能训练线、思政浸润线的“三线”共振育人的课程思政教学目标,运用现代信息技术创建多元化混合式教学方式,在教学目标、教学内容、教学方法、教学过程及教学评价中融入思政教育,形成全方位的课程思政体系。

模具设计与制造专业班会内容与PTS人生技能课程相融合的研究

模具设计与制造专业学生的班会内容与专业拓展课《PTS人生技能》的内容相融合,先分析模具设计与制造专业的培养目标,阐述拓展课的8个模块,并以“理解和管理情绪模块”为例进行了主题班会的实施过程的介绍。班会内容与PTS人生技能课的融合是一种有益的尝试,班会中应用了课程的“演、思、说、用”4个环节。以学生为中心的理念,经验学习圈理论。让学生在班会中学习和应用人生技能,提升了个人综合素质,为学生的全面发展提供有力支持。

模具制造技术的发展与创新

模具制造技术是现代制造业的重要组成部分,其发展和创新直接影响着制造业的生产效率和产品质量。分析了模具制造技术的发展与创新,以期为相关领域的研究者和实践者提供参考。

轴承坯料机械手轴盖3D多工位级进模设计

针对轴承坯料机械手轴盖制件一套三件的成套冲压成型生产要求,运用3D设计软件UG设计了一副11工位连续级进模用于轴盖成套制件的生产。模具中所设计的11工位包括冲孔、落料、拉深、翻边、侧切、侧冲孔等工艺成型手段,模具达到的效果是材料利用率达到64.23%,制件生产效率可达45套/min,模具制造成本降低5%。相比于传统多工序多套单冲模成型工艺,生产效率提高10倍以上。模具中,使用1次拉深成型、3次精修,对多级拉深成型件进行加工能有效降低制件加工难度;使用步进电机送料,氮气弹簧压料和顶料,使模具设计难度大为降低;使用了两种楔紧块驱动型侧滑块机构对制件进行工艺面切除加工和精整形,及燕尾槽压块驱动上模侧冲孔滑块机构使制件的侧面加工得到了可靠保证。使用UG设计软件设计了模具的3D结构,较之于2D排位设计方法,更能有效避免设计缺陷,模具设计效率和可靠性更高。

关于注塑件脱模力计算公式的修正

结合注塑件脱模力的计算公式,塑件收缩对模具型芯产生的包紧力与塑件对模具型芯产生的正压力出现混淆的问题,以圆筒形塑件及空心矩形体塑件为例,通过分析塑件收缩对模具型芯产生的包紧力在塑件脱模前后与塑件对模具型芯产生的正压力的变化,推导得到包紧力计算公式,说明了包紧力与正压力的区别。为了进一步分析脱模力及包紧力的变化,研究了拔模斜度α与脱模力修正系数K的关系曲线及包紧力脱模力的比p/q与脱模力修正系数K关系曲线,结果表明,在相同参数条件下,随着脱模力修正系数K的增大,拔模斜度α曲线呈线性关系,包紧力脱模力的比p/q曲线呈非线性关系。最后,根据以上研究及实际情况修正了塑件脱模力计算公式。