橡胶模型制品胶坯精密预成型机

介绍了橡胶工业橡制品生产中胶坯制备的三种方法，其中详细介绍了精密预成型机制备胶坯。以上海德仁橡塑机械有限公司物精密预成型机为例，从结构，性能及工艺参数等方面进行了分析，说明精密预成型机是批量生产橡胶模型制品的一种得力辅助设备。     

螺纹切头中螺纹梳刀的运动分析

螺纹梳刀是加工螺纹一种刀具,被广泛应用于加工石油、建筑行业用的螺纹中。螺纹梳刀切头加工螺纹的最大优势在于效率高,将加工时间缩短一半以上,并且能保证工件的受力平衡,特别是应用在活动钳口螺纹的加工上。本文探索螺纹梳刀的结构特点,分析了螺纹梳刀的发展,同时在Pro/E中进行模拟加工及运动分析。     

Machinability of Metal Matrix Composites Reinforced by 3-D Network Structure

Metal matrix composites reinforced by three-dimensional (3-D) continuous network structure reinforcement (3DCNRMMC) are difficult to machine due to serious tool wear and poor surface roughness caused by the brittle and hard reinforcement which interpenetrate into ductile matrix. In order to achieve the approach of low cost of 3DCNRMMC, the machinability of it needs to be understood. The influences of three cutting parameters and volume fraction of reinforcement on cutting force were analyzed in detail. The results indicate that: (1) Due to the brittle phase(s) introduced into ductile matrix of composites, there is a large fluctuation of cutting force causing deterioration of machinability. The fluctuation ranges of cutting forces, initially increase rapidly with the increase of volume fraction of reinforcement and then decrease finally, are largest at the range of the volume fraction of 55–65%; (2) The influence of cutting parameters on cutting force is obvious. With the increases of cutting speed, cutting force decreases gradually unless cutting speed exceeds the value of 209 m/min. Cutting forces increase with increasing feed rate and depth of cut; (3) Owing to the large fluctuation of cutting force, there were some cratered surfaces caused by Si₃N₄ reinforcement pulling-out and flaking-off. Some brittle phase protruding from the machined surface caused the deterioration of machined surface.     

用微机CAD/CAM一体化系统─SCADAM求解锥形导叶空间密合线及密合倾角

叙述了用ＳＴＡＲＣＡＤ／ＣＡＭ求解贯流式水轮机锥形导叶空间密合线及密合面倾角的条件、方法及过程。     

基于r2法刀具偏移计算实现

本文详细介绍了r2法实现刀具偏移计算的基本原理和实施方法.     

The Effect of Coolant Concentration on the Machinability of Nickel-Base, Nimonic C-263, Alloy

This paper investigates the effect of coolant concentration on tool performance when machining nickel-base, C-263, alloy with triple coated (TiN/TiCN/TiN) carbide insert at various (3–9%) coolant concentrations and under different cutting speed conditions. Tool life, tool-failure modes, wear rates, component forces and surface finish generated during machining were recorded, analyzed and used to formulate mechanisms responsible for tool wear at the cutting conditions investigated. Analysis of the recorded data shows that tool performance during machining is dependent on coolant concentration. 6% coolant concentration gave the best overall performance as effective combination of cooling and lubrication functions were achieved during machining. Increasing coolant concentration to 9% reduced tool performance due to a reduction of the tool-chip contact length area and the consequent increase in compressive stresses at the tool-chip and tool-workpiece interfaces. This action often leads to pronounced chipping of the tool cutting edge during machining. Friction coefficient between the workpiece material and substrate increases once the coating layer(s) is broken as a result of the direct contact between the tool substrate and the work material. This action increases mechanical wear of the tool, which in turn leads to a significant increase in the cutting force with negligible effect on the feed forces during machining.     

Optimization of abrasive water jet cutting of ductile materials

Full factorial design of experiments was developed in order to investigate the effects of jet pressure, abrasive mixing rate, cutting feed, and plate thickness upon three response variables, surface finish of cutting wear zone, percentage proportion of striation free area, and maximum width of cut. The set of sixteen experiments was performed on each of the following two ductile materials: AISI 4340 (high strength low alloy steel, hardened to 49HRc) and Aluminum 2219. Analysis of Variance (ANOVA) was performed on experimental data in order to determine the significance of effects of different parameters on the performance measures. It was found that cutting feed and thickness were highly influential parameters, while abrasive mixing rate is influential upon surface roughness only. Strong interaction was found between jet pressure and workpiece material. Multi-criteria numerical optimization was performed in order to simultaneously maximize/minimize different combinations of performance measures.     

岩石切削过程中破坏机制的离散元分析

利用离散单元方法(DEM)对两种不同属性的花岗石样本模型进行了切割模拟,通过调整不同的切削参数计算并分析了岩石切削过程中的切削力、切削深度、切削比能及切削力倾角的变化规律,从细观上探讨了临界切深对岩石脆性破坏模式和塑性破坏模式及其转变的影响,指出了当切削深度逐渐增大时,破坏模式依次从塑性破坏模式到过渡破坏模式最后转变为脆性破坏模式,同时切削力倾角并不随切削深度变化。将离散单元法分析的结果与实际实验进行了比较,表明该方法是合理的。     

新型钻镗刀的应用

介绍了一种新型复合刀具——ECOCUT钻镗刀,以及该刀具在数控加工中与普通刀具的综合对比情况.