Technology chain optimization: a systematic approach considering the manufacturing history

The optimization of technology chains is usually conducted as a local problem of each individual process step. However, in order to optimize the technology chain in terms of product properties a local optimization is insufficient and a more holistic approach is indispensable. Existing methods, which consider the manufacturing history of a workpiece, are often accompanied by a high level of effort in research. This paper presents a systematic approach to integrate the manufacturing history into the technology chain optimization process going along with a significant reduction of effort compared to existing methods based on simulation and experiments. Resulting from previous methods and models a set of representative variables is identified to describe interactions and dependencies within technology chains. Furthermore, an approach consisting of three steps is developed which allows a visualization as well as an explanation of the cause-and-effect relationships within technology chains. This approach is used to deduce two different optimization strategies for technology chains. The first strategy allows a global optimization by adjusting specified parameters without changing the processes within the technology chain. Whereas the second strategy comprises a redesign of the whole chain.     

Application of methods for ecological optimization of crank shaft forging process

The manufacturing process of forged parts is usually conducted by different subsequent process steps. According to various technological as well as economical and ecological requirements, different and often opposing objectives have to be fulfilled. A representative example for this conflicting situation is the requirement of high product qualities on the one hand and low processing costs on the other hand. A third important factor influencing the process in addition to quality and cost-efficiency is the ecological aspect that is focused more and more in recent years. Material shortage, high energy costs and increasing intensification of statutory regulations lead to the necessity of ecologically optimized processes. Nevertheless, an economic-based evaluation of forging processes is not easy to carry out due to a versatile process chain from raw material to final product. Within the framework of the joint research project “Holistic process chain optimization for forging production of automotive parts in terms of manufacturing efficiency and saving operation energy” an entire evaluation and optimization with special regard to ecologic aspects will be conducted on the example of a crank shaft forging process (Denkena et al. in ZWF 4:224–228, 2013; Int J Precis Eng Manuf 14(7), 2013).     

The virtual production simulation platform: from collaborative distributed simulation to integrated visual analysis

Computational simulations are used for the optimization of production processes in order to significantly reduce the need for costly experimental optimization approaches. Yet individual simulations can rarely describe more than a single production step. A set of simulations has to be coupled to each other to form a contiguous representation of a process chain. Eventually, simulated results have to be analyzed by domain experts to gather insight from the preformed computations. In this paper, we propose an IT infrastructure and software tools that aim at a rather non-intrusive way of coupling resources and domain expert’s knowledge to enable the collaborative setup, execution and analysis of distributed simulation chains. We illustrate the approach in the domain of materials processing. Beyond means originating from the domain of GRID computing for resource management, a data integration component assures semantic data integrity between the simulation steps and stores simulation data in an application independent way. Thus, we can transform this data into native formats for each simulation tool, and finally into a format that allows for contiguous visualizations and an intuitive, comprehensive analysis of complete simulated process chains.     

大型锻钢支承辊生产状况及最终热处理工艺

概述了支承辊的工作条件及性能要求,国内大型锻钢支承辊的生产状况、工艺及设备;重点介绍了大型锻钢支承辊的最终热处理工艺,包括差温淬火、感应淬火。     

Investigation of the coating thickness of plasma-transferred arc deposition welded and cross wedge rolled hybrid parts

Most of today’s technical parts and components are made of monolithic materials. These mono-material components produced in established production processes reach their limits due to their respective material characteristics. Thus, a significant increase in production quality and efficiency can only be achieved by combining different materials in one part. Bulk forming of previously joined semi-finished products to net shape hybrid components that consist of two different materials is a promising method to produce parts with locally optimized characteristics. This new production process chain offers a number of advantages compared to conventional manufacturing technologies. Examples are the production of specific load-adapted forged parts with a high level of material utilization, an improvement of the joining zone caused by the following forming process and an easy to implement joining process due to the simple geometries of the semi-finished products. This paper describes the production process of hybrid steel parts, produced by combining a plasma-transferred arc deposition welding process with a subsequent cross wedge rolling process. This innovative process chain enables the production of hybrid parts. To evaluate the developed process chain, coating thickness of the billet is analysed before and after cross wedge rolling. It could be shown, that the forming process leads to an improvement of the coating, meaning a more homogeneous distribution along the main axis.     

锻造方式对TC4钛合金小规格板材制备的影响

TC4钛合金小规格板材生产一般采用铸锭镦拔锻造、板坯加热轧制的加工方式进行,对于小规格板材通常锻造时采用镦拔锻造的方式来进行,但组织性能并不能达到相对最优的状态.通过关键过程交叉对比的方式,采用普通自由锻造和镦拔锻造两种加工方式生产出相同尺寸的板坯,再使用相同的轧制工艺进行对比生产,所有的生产环节保持一致性,目的在于探...     

Holistic modelling of process machine interactions in parallel milling

Parallel milling allows to increase the manufacturing capacity in industry due to a higher cutting productivity. The latter is often negatively influenced by dynamical instabilities of the parallel milling process entailing a reduced profitability. In this paper a holistic model of interactions between a double spindle machine and a parallel milling process is presented that enables an identification of the dynamic compliance of parallel milling machines and a simulation of their stability behaviour. With that an investigation of stability optimization means is possible. A significant improvement of the process stability and, thus, the effective cutting productivity was observed in the parallel milling processes, optimized with help of the holistic model.     

Development of a reliable grinding procedure for ceramic medical instruments

Surgical instruments have to meet strict requirements on functionality and stable performance. The functional properties of scalpels, for example, are mainly dependent on a precise cutting edge geometry and high blade sharpness. To achieve a reliable production of scalpels, it is necessary to establish a holistic understanding of the process chain as well as the interactions of all machining processes. An innovative zirconium oxide offers high toughness and high wear resistance, leading to its use in ophthalmic scalpels. A cooperative project has been conducted by two universities and two industrial partners, funded by the German Federal Ministry of Economics and Technology (BMWi).The project focuses particularly on the grinding process as a controlling factor for the scalpel’s functionality and sharpness. The complex process chain with various interactions of kinematics, vibrations and tool micro-topography was developed for high reliability and efficiency. The performance of in-machine dressing of diamond wheels with diamond form rollers was decisive for scalpel quality.     

Design concept for a transparent supply chain

The production companies have been concentrating increasingly on their own core-competencies while outsourcing their secondary production processes at the same time. Apart from the advantage of efficiency, however, this strategy leads to an increase in inter-company distribution of labor resulting in a strong dependence on reliable supply relationships. Consequently, closer co-operations in form of supply chains have to be set up in order to cope with the mutual dependencies of the supply chain processes. The article deals with this subject and proposes a solution concept for the design of supply chains. The solution concept is divided into four stages and enables the production companies to govern and control the complexity and transparency of their supply chains.     

大型锻钢支承辊锻后热处理工艺优化实践

根据近 1 0 0支锻钢支承辊的锻后热处理的工艺实践 ,摸索出了一套此类支承辊的锻后热处理工艺 ,缩短了生产周期 ,提高了效率 ,降低了成本 ,保证了质量。     

基于有限元法的正反向模拟技术在链轨节锻造中的应用

锻造过程的预成形设计是提高锻造质量和降低产品成本的一个极其重要的方面，基于刚一粘塑性有限元法的正反向模拟技术能够从最终的锻件形状直接得出坯料的预成形形状，通过改善设计制坯操作来减少作为飞边的材料浪费。中介绍了覆带链轨节锻造的常规工艺，说明了目前覆带链轨节锻造中存在的问题，阐述了有限元法、预成形设计思想和正反向模拟技术以及它们在覆带链轨节锻造中的应用。     

铁路货车钩尾框的锻造工艺

根据铁路货车重载提速提出了采用锻造工艺制造钩尾框的要求。由于钩尾框形状复杂、体积庞大,导致其锻造的工艺难度较大。介绍了铁路货车钩尾框锻造工艺,包括工艺的分析、研究、制定和修整的全部过程。通过对不同的锻造工艺进行分析比较,提出了合理的锻造工艺方法,并成功地应用于17型和16型锻造钩尾框的生产。     

某汽轮机叶片材料热变形行为及锻坯参数优化

为提高某叶片锻件质量和生产效率、减少模具磨损,采用热模拟试验研究了叶片材料的热变形行为,建立了材料的高温流动应力方程;以此方程作为材料模型,对叶片的锻造过程进行了数值模拟,优化了制坯工艺参数.试验分析表明,该材料热变形行为符合双曲正弦函数关系;数值模拟结果表明,采用叶根与叶冠成40°角的坯料较优,成形质量与成形载荷对坯...     

Adaptive process planning

The success of companies with job shop production strongly depends on their production flexibility. This is often significantly influenced by the process planning and production control. Aiming at maximizing production flexibility, this paper presents an approach to further integration of process planning and production control by combining and optimizing already existing planning methods. Essentially, in a rough planning stage, all process chains which are technological relevant to the manufacturing of a given product are taken into consideration. Applying a dynamic multi-criteria evaluation to all process chains ensures that the most appropriate, situation-specific process chain is chosen for production. This is done based on pre-established production targets, which facilitates a flexible response to incidents and other unplanned production events. The structure and functionalities of the presented approach are thoroughly explained in this paper and its feasibility is demonstrated with an example.     

不锈钢壳体锻造工艺与锻模设计

以不锈钢壳体锻造为研究对象,分析了锻造工艺性,制定了锻造工艺和锻模设计的优化方案,改善了锻造工艺性,达到了不锈钢壳体锻造技术上可行、质量上可靠和经济上合理的效果。     

A study on the development of a substitution process by powder metallurgy in automobile parts

Powder metallurgy processes using sintering are able to form net-shaped products and have been used widely in the production of automobile parts to improve productivity. However, the toughness of powder products is generally poor because they contain pores. Therefore, forged products are used in parts subjected to severe fatigue loads, but in the case of powder products having high toughness, they could substitute for forged products. In this study, the choice of powder materials and production processes, including mixing, compaction, sintering, and heat treatment are studied to produce the clutch disc spline hub of an automobile. For this, three types of materials are selected and processed and the mechanical properties and microstructure of the sample are investigated, along with the performance of a dynamic test carried out under real conditions.     

铲齿的模锻工艺设计

铲齿是一种常用的工程机械零件,该零件结构复杂,成形困难.联合锻造是有效地解决这类零件成形困难的方法.介绍了联合锻造成形工艺的特点,结合实际生产条件,以标准齿工件为例,采用联合模锻工艺,成功地解决了该零件模锻生产中出现的工艺缺陷.此类零件成形过程容易出现折叠和充不满,通过设计合理的预制坯,解决了变形时坯料的分配;用分步变形来控制冲孔变形量,避免了方口边缘充填不足和内腔折叠缺陷的产生,保证了复杂孔型的最终成形,实现了批量生产的目标.     

Holistic process planning chain for robot machining

Today, machining of large, integral constructed structural parts requires expensive machining centers. In contrast, modern industrial robots are suitable for a wide field of applications and are characterized large working spaces and low capital investment. Therefore, they provide high economical potential for machining applications in aerospace industry, especially for the machining of near to shape pre-products like extruded profiles. However, their constructive characteristics like low stiffness and high sensitivity to vibrations lead to disadvantages compared with conventional machining centers and have to be considered during process planning. Therefore, several methods for offline and online optimization of robot machining processes were developed and integrated in a new process chain for manufacturing of structural fuselage parts. Thereby, the conventional CAD–CAM process planning chain was extended with simulation based analysis and optimization methods and a load-depending trajectory planning. These methods for offline process optimization within this novel process chain are presented in this paper.     

曲轴先进锻造技术的研究与应用

通过对曲轴锻件产品的结构特点和锻造工艺分析,提出了今后曲轴的生产将更多的采用大型自动化生产线,模锻锤生产工艺将逐渐被淘汰。随着国家节能改造技术的推广应用,曲轴锻造用钢材将由调质钢向微合金结构钢转化,同时,一些新的技术、新工艺也将更多的应用于曲轴锻件的生产,将极大的促进我国曲轴锻件市场的发展和国际竞争力。