注塑件/注塑模报价及成本评估方法综述

介绍了注塑模的报价特点、报价方法，并对国内外注塑件／注塑模成本评估的主要研究方法进行了分析，利用CBR方法给出了自己的研究思路。     

Hot shear spinning of cast aluminium alloy parts

A hot shear spinning process of cast aluminium alloy parts was developed to eliminate casting defects and to obtain a desired distribution of wall thickness. The forming load of the shear spinning is comparatively low even for large deformation requisite for eliminating the casting defects. Dendrites and shrinkage cavities in the cast aluminium alloys were successfully eliminated without occurrence of a fracture by the hot shear spinning. Surface cracks around the corner of the mandrel caused by large shear deformation were reduced by decreasing the feed rate of the roller and by increasing the tip radius of the roller. It was found that hot shear spinning is effective in improving the mechanical properties of cast aluminium alloys parts.     

Fatigue life estimation of cast components

An engineering method based on fracture mechanics is suggested for life predictions of components of nodular cast iron. The method should be applicable to any structure containing defects which can cause crack initiation. Component testing was performed and the observed results were compared with model predictions. Fatigue crack growth data were obtained by testing on CT specimens even for load ratios R < 0. By accounting for crack closure the R-effect on the growth rates can also be effectively eliminated for this type of material.     

Deformation-heat treatment to stabilize the dimensions of cast iron parts

Conclusions We established the basic parameters determining the effectiveness of aging cast iron parts by means of thermal impact and also the heat treatment conditions. It was found that this is a reliable method for stabilizing the dimensions of parts. The main advantage of the process is high productivity with good quality. The heat treatment can be conducted in ordinary furnaces used for annealing castings.ÉNIMS. Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 4, pp. 37–41, April, 1971.     

汽车覆盖件模具制造过程简述

介绍汽车模具制造工艺流程,围绕提升模具质量、缩短模具制造周期、降低模具制造成本进行论述,并分析模具制造的不足及各工序常见的问题,并提出各种问题的解决方法,为模具制造及加工的整个过程如何保证其质量提供参考。     

High-strength cast irons used for manufacturing parts of vaz passenger cars

Methods for solving problems arising in the production of high-strength cast iron with stable properties and structure are considered. Results of introduction of new grades of high-strength cast iron instead of malleable cast iron and camshaft cast iron in the Volzhskii Automobile Plant are described.Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 10, pp. 21–23, October, 1996.     

高强度/高韧性铸态汽车球墨铸铁件生产技术

①介绍了东风汽车公司多年生产铸态高强度球铁及高韧性球铁铸件的径验；②与热处理工艺对照取得的经济效果；②铸态生产的关键是化学成分的控制和恰当的孕育处理；④提出了球铁发展与研究的几个问题。     

Manufacturing of micro thin-walled metal parts by micro-droplet deposition

Metal micro-droplet deposition manufacturing technique is a novel direct metal rapid prototyping for building the miniaturized parts. In this paper, the novel direct metal rapid prototyping was proposed to fabricate micro thin-walled metal parts. A direct droplet fabrication experimental system was developed based on the forming principle of micro-droplet deposition manufacture. Several deposition experiments were conducted to investigate the influences of process parameters on the formed wall thickness and deposition accuracy of droplets. The experimental results show that the proper deposition distance Hs for obtaining high deposition accuracy of droplet ranges from 1 mm to 20 mm; the formed wall thickness W can be controlled by selecting different nozzle diameters D and formed angle of deposited droplet θ. According to the experiment results, a micro thin-walled structure with wall thickness of 400 μm was fabricated by adjusting the process parameters. The above research works show that it is feasible to fabricate the micro thin-walled metal parts by micro-droplet deposition manufacturing technique.     

Metallographic problems of the production of parts from continuously cast high-speed steels

It has been assumed until recently that high-speed steels cannot be produced by the method of continuous casting. Numerous attempts to use this highly efficient technology for manufacturing such steels have failed because of breakage of the cast preforms. A solution was sought in improving the design of the continuous-casting machines (CCM), increasing the level of their automation, and using rational compositions of slag-forming mixtures (SFM). The idea was that a high-speed steel can be cast only in vertical CCM. The present work concerns regimes of secondary cooling under which the structures formed in high-speed steels provide a ductility sufficient for bending the continuously cast preform without failure. Steel R6M5 cast continuously in such a machine can easily be machined into hot-rolled preforms for sheets, wire, silver-steel rods, and other final products without a forging stage. Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 9, pp. 6–13, September, 1998.     

Early cost estimation for tolerance verification

This paper presents a methodology for estimating the verification cost of geometric tolerances at the design stage, which is useful for optimizing the tolerance specifications of mechanical products. The tolerance verification cost may be seen as the sum of the measurement and uncertainty costs. The measurement cost depends on the adopted device and on the measurement time. The uncertainty cost is related to type A (declaring a conforming part non-conforming) and type B (declaring a non-conforming part conforming) errors: these errors are strongly influenced by the measurement procedure, which depends on the measurement device and determines the measurement time. The methodology is illustrated and validated using simulation and industrial case studies.     

Mechanism and estimation of porosity defects in ductile cast iron

Abstract

Although there are many works on the formation mechanism of porosity defects due to solidification in ductile cast iron, the formation mechanism is still not clear and decreasing the porosity defects is still a main issue in the industry. This paper critically reviews conventional explanations for the porosity formation including estimation methods. Based on the discussion the authors propose a formation theory where it considers gas and oxide entrapment during mould filling, expansion of outer part of casting due to graphite formation and pressure decrease in the inner part, followed by the growth of entrapped small gas bubbles. This mechanism can explain various facts in practice and be usable to estimate the defects. It also gives a good way to design effective risers. Future challenges are also discussed including the effect of inoculation on the fluidity of the mushy region.