船用薄板CO_2焊控制焊接变形工艺研究

采用药芯焊丝CO2气体保护焊工艺对控制船用4mm薄板的焊接变形进行了试验研究,结果表明采用该工艺能较好地控制船用薄板的焊接变形,并得出了控制焊接角变形3°和纵向挠曲变形量在±6mm范围内的合理焊接工艺参数。     

基于PLC控制的冲床薄片自动供料系统设计

针对冲床薄片自动供料在工艺系统中的应用,从工艺要求、控制方案拟定和控制系统硬件设计进行研究,采用PLC控制系统可以使系统达到体积小、控制灵活、故障检测容易,提高生产率的目的。     

支架体的消失模铸造工艺研究

讨论了采用消失模工艺生产叉车气缸支架体的工艺研究和实验方案，提出了该铸件生产工艺控制和缺陷控制的方案和方法。     

中频热推弯管工艺参数自动控制

提出了中频热推弯管工艺加热温度与推制速度两个工艺参数的自动控制方案。该方案采用两个单片机协同完成管坯推制成形过程中的感应加热温度检测和中频电源整流逆变控制 ;采用一个单片机完成热推弯管机液压系统推制速度控制。因此 ,使这两个工艺参数在给定的优化域内自动实现合理匹配 ,工艺过程实现自动控制     

防止中硅耐热球墨铸铁管架冷裂纹的产生

采用控制硅量、改进铸造工艺和合适的退火工艺,消除中硅耐热球铁管架的冷裂纹。     

乌东德左岸水电站转子支架焊接工艺

乌东德左岸电站转子支架采用弱约束对称焊接工艺，打破了水电史上转子支架约束焊接工艺的传统，其主要特点是取消了添加和割除骑马板的工序。采用该焊接工艺可缩短焊接工期，降低焊缝内应力，提升转子支架焊接质量。文中归纳总结了乌东德左岸电站圆盘式转子支架弱约束对称焊接工艺的控制方法，重点分析了焊接过程中转子支架各特征部位变化趋势和焊接质量控制的工艺措施，对大型圆盘式转子支架弱约束对称焊接工艺的控制提供科学依据。     

机车齿轮渗碳热处理工艺控制

对机车传动齿轮采用渗碳淬火热处理工艺控制进行研究,其中包括修碳温度和时间,渗碳层质量,淬火温度和时间等工艺参数的合理选择,并对渗碳淬火变形原因与控制进行分析探讨。     

基于PID的模具激光熔覆再制造工艺控制研究

采用增量式PID算法建立了模具连续CO2激光熔覆工艺控制模型,并对其进行了仿真试验.结果表明,与传统控制方法相比,基于神经网络的PID技术的新型控制模型具有更好的自适应性、鲁棒性和控制精度,改进并优化了模具激光熔覆再制造工艺.该新型控制模型可以推广应用到其他种类的模具激光熔覆工艺过程控制中.     

等温锻造对镁合金汽车悬架控制臂性能的影响研究

采用不同的锻造工艺对AZ31-0.15%Ce镁合金汽车悬架控制臂进行了锻造,并进行了力学性能和耐腐蚀性能的测试与对比分析。结果表明:与常规锻造相比,采用等温锻造方式制备的镁合金汽车悬架控制臂力学性能和耐腐蚀性能得到显著提高。该悬架控制臂的最佳锻造工艺为等温锻造,其工艺参数为模具预热温度410℃、锻造温度410℃、锻造速度120 mm/min。     

工程机械用低合金高强度钢的实验室试制

通过实验室模拟控制轧制及不同的冷却工艺,成功试制了具有良好综合力学性能的工程机械用低合金高强度钢,并研究了在不同工艺下的组织和性能.结果表明:试验钢采用两阶段控制轧制和直接淬火+低温回火工艺生产的钢板强度最高,其抗拉强度为1838 MPa、屈服强度为1531MPa;采用层流冷却+等温碳分配+低温回火冷却工艺生产的钢板韧性最高,室温及-40℃冲击功分别为48、32J.     

基于神经网络的直流无刷电机控制系统

提出了一种直流无刷电动机的N-PI转速调节器的设计方法.在直流无刷电动机的高性能速度跟踪中,若仅采用传统的PI调节器,则难以克服系统超调和短时振荡问题.采用复合N-PI的控制方法,利用神经网络的自学习自适应功能在线调整PI控制参数.文中提出了一种模型参考自适应与神经网络相结合的控制策略,利用在线辨识技术,对参数变化实时补偿,及时修正神经网络权值的计算.最后,在Matlab/Simulink下进行了仿真,结果表明,运用这种设计方法很好地抑制了超调和振荡.     

金刚石热稳定性分析装置的研制

人造金刚石的热稳定性能是评价金刚石质量的一个重要指标，以往采用热重法测定，本文介绍一种新的仪器，可更方便，更直观的测定，并且成本低廉。     

数值模拟铸件充型过程中的液/固两相流动

铸造过程中熔融金属内的固体渣粒的运动轨迹是非常重要的。文中给出了粒子传输轨迹的数学模型,该数学模型采用显示法来确定粒子的位置。模拟研究结果与用其它数学模型的模拟结果比较,吻合良好。该模型可用于固体粒子位置的确定,并应用到SUTCAST软件中。     

Integrated planning for precision machining of complex surfaces. Part 1: Cutting-path and feedrate optimization

In order to achieve higher productivity and product quality simultaneously for sculptured surface productions, two advanced strategies are proposed for machining planning, namely a cutting-path-adaptive-feedrate strategy and a control surface strategy. In the cutting-path-adaptive-feedrate strategy, machining time is reduced by cutting along low-force-low-error machining directions and by maximizing feedrates. In the control surface strategy, machining errors are minimized by using a compensated control surface based on predicted machining errors. In part 1 of this paper, the cutting-path-adaptive-feedrate strategy, which improves the productivity of sculptured surface machining when subjected to both force and dimensional constraints, is described. In this proposed strategy, a new machining-planning aid called a maximum feedrate map is developed. In this map, the maximum allowable feedrates, subjected to the specified constraints, at each control point along various machining directions, are determined using a surface generation model. These local maximum-feedrate boundaries indicate the acceptable range of feedrates that a part programmer can use in the NC programming. In addition, the maximum feedrate map also provides the part programmer an important aid in selecting the cutting directions. In order to illustrate the application of the maximum feedrate map and to examine the capability of the proposed cutting-path-adaptive-feedrate strategy in improving the productivity of sculptured surface machining, simulation studies of a two-dimensional curved surface are performed and the results are presented in this paper. The applications of the proposed strategy to real three-dimensional complex surfaces (e.g. a turbine blade die) along with experimental verifications are presented in part 2 of this paper. In part 3 of this paper the control surface strategy and its applications to the finish milling of three-dimensional complex surfaces are discussed.     

产品多领域协同设计过程建模方法

多领域协同设计过程是基于约束的、多领域协同的设计过程,该过程产品信息增量最大,以此为基础,构建了多领域协同设计过程的整体框架和设计过程基本单元模型,为多领域协同设计过程管理系统的建立提供了条件;另外,初步建立了多领域协同设计过程的数学表达模型,利用该模型可进行设计过程冲突检测。     

盒形件法兰皱曲失稳的临界条件

在盒形件拉深成形智能化控制过程中,为了防止法兰起皱的产生,必须认识起皱发生的机理,进而对起皱的发生进行控制.本文基于一点应力状态的C-B准则建立了应用与判断法兰起皱的判断准则,完善了起皱的预测方法,给出了获得起皱的临界行程与压边力关系曲线的方法,这为进一步实现法兰起皱的实时预测提供了依据.     

Earliness-tardiness-lost sales dynamic job-shop scheduling

In the real world production environment, the decision about the acceptance or rejection of new orders is made by both the sale department and the production department, cooperatively. However, as far as we searched, no published paper has considered this fact so far. Job-shop scheduling is one of the most complex problems in scheduling. In job-shop environment, there are some production stations, and every job (order; In this paper job and order are used in the same meaning) has a specific production sequence which is not necessarily the same as the other jobs’ sequences. This paper studies the earliness-tardiness-lost sales dynamic job-shop scheduling problem. In this problem, whenever some new orders arrive, a decision is made about the acceptance or the rejection of each of these orders. In this way, all of the alternatives, including the acceptance or rejection of each new order, should be compared. If at least one new order is accepted, the new schedule which includes the accepted order(s) will be generated. By defining some variables, this comparison is done by the developed models. Because of NP-hardness of this problem, exact methods can not be used to solve it in large or medium scales. So, in this paper a hybrid metaheuristic algorithm is developed, which is composed of a genetic algorithm to determine the sequence of the operations and a simulated annealing algorithm to achieve a near-optimal schedule based on this sequence. Finally, the efficiency and effectiveness of the algorithm is evaluated using some numerical results.     

Prevention of Exit Crack in Micro Drilling of Soda-Lime Glass

In micro drilling of glass plates, cracks occur at the exit surface. In this work, a back-up glass plate was used to prevent the exit crack. The mechanical lateral constraint was applied to the workpiece and the back-up glass plate to reduce tensile stress near the drill corner. In this way, crack-free holes could be produced. In order to avoid careful fixturing for the mechanical constraint, two glass plates were adhered with various liquids. It is shown that the liquid adhesion of the back-up glass plate without the mechanical constraint is a more effective method to prevent exit crack.     

Machining stability in high-speed drilling—Part 1: Modeling vibration stability in bending

In this work, dynamic models for chatter in drilling are developed that deal with the transverse vibration due to bending, and the axial vibration due to torsion. In the first part, a dynamic model is developed to obtain the limit of stability for the bending vibration mode. The equations of motion are formulated based on a lumped representation of the drill, and the gyroscopic effect due to the rotation of the tool is included. It is shown that, including this gyroscopic effect has a profound effect on the resulting stability lobes, especially at very high speeds; it makes the lobes wider but at the same time lowers the minimum stability boundary. In the second part of this work, a time domain simulation model is developed that combines both bending and torsion modes. This model is verified [1] using experimental cutting tests.     

基于拉深孔成形技术的圆筒件拉深新工艺的实验研究

文章提出了一项能大幅提高板料拉深成形性能的新技术———拉深孔成形技术,描述了基于该技术的圆筒件拉深新工艺的实验情况,展示了成功的实验结果,并将常规工艺与新工艺在同一条件下得到的实验结果进行了对比,验证了新工艺的可行性和有效性;探讨了拉深孔成形技术的机理,并给出了合理、完备的解释。