圆柱插补功能在数控车铣加工中心的应用

随着社会生产和科学技术的发展,机械产品日趋精密复杂,这推动了数控加工技术的高速发展,数控车铣加工中心应运而生,它能通过一次装夹零件完成多种加工工序,大大提高生产效率,而掌握车铣加工中心编程方法就成为使用车铣加工中心的关键技术。本文介绍数控车铣加工中心的功能、特点和使用圆柱插补功能加工圆柱凸轮槽零件的编程方法。     

车铣复合机床回转轴精度检测和误差补偿分析

介绍自行研发的车铣复合机床,分析机床的误差源和提高机床加工精度的方法,并且通过Renishaw ML10激光干涉仪和RX10旋转轴校准器系统对车铣复合机床B轴位置精度进行了检测,根据检测结果进行误差补偿研究和实验验证。实验结果表明补偿后B轴位置精度可满足车铣复合机床的加工精度要求。     

螺纹型芯在车铣复合中心的加工

介绍了DMG GMX 250车铣复合中心的机床特点。通过对防盗盖螺纹型芯零件特点的分析,提出了常规刀具角度偏摆的加工方法,建立了基于车铣复合中心加工的新型方案及工艺流程,解决了生产过程中出现的问题。该方案提高了产品的加工精度,降低了加工成本,经批量使用,产生了良好的经济效益。     

数控车铣加工中心C轴编程方法

车铣复合加工是利用铣刀旋转和工件旋转的合成运动来实现对工件的切削加工,使工件在形状精度、位置精度、已加工表面完整性等多方面达到使用要求的一种先进切削加工方法。车铣复合加工不是单纯的将车削和铣削两种加工手段合并到一台机床上,而是利用车铣合成运动来完成各类表面的加工,是在当今数控技术得到较大发展的条件下产生的一种新的切削理论和切削技术。掌握车铣复合加工中心手工编程技术成为关键,本文介绍数控车铣加工中心的功能、特点和使用C轴功能加工六边形零件及端面圆弧槽及钻孔加工方法。     

铣车复合加工解决方案

随着全球对创新的愈发重视,新技术的快速发展,产品的结构越来越复杂,产品零件的精度要求也越来越高,对加工母机机床提出更多高效、高精的要求。复合机床因一次装夹多工序加工的特性,在大批量生产、复杂结构、高精度等场合成为一个很有优势的选项,成为越来越多企业的选择。针对这种发展趋势,推出了一种先进的铣车复合加工解决方案。这种铣车复合解决方案能够实现一次装夹实现复杂的零件多工序的加工,达到提升效率和加工精度,且对加工产品的表面粗糙度也能达到很好的效果。     

长征机床集团高端重型新产品研制成功

DMC1000重型铣车复合加工中心该产品采用了当今机床先进技术,具有大功率、高精度、高刚度的显著特点,能进行车铣钻等复合加工。具有X、Y、Z1、Z2、Z3、B、C1、C2 8个坐标轴,可实现八轴五联动。采用XY轴相垂直布局方式,有效增大Y轴行程,扩大加工范围;铣削、车削刀具均在同一工具主轴下装卡,可实现大型船舶曲轴等复杂零件一次装卡下铣车复合加工。     

海德汉年推出数控系统、光栅尺、编码器和测头等新产品

<正>2012年海德汉将推出数控系统、光栅尺、编码器和测头等多种新产品。其中,有适用于车铣复合加工机床的TNC 640轮廓加工数控系统和用于机床的LC 415和LC 115绝对式封闭直线光栅尺和用于大长度测量的LC 200绝对式封闭直线光栅尺及应用在精密机床(如坐标镗床和磨床、机床的直线电机)高精度方向控制     

基于车铣复合中心的针阀接头数控加工

介绍利用车铣复合中心加工针阀接头零件的新工艺,重点分析加工难点的工艺过程,解决了采用普通数控加工方法加工精密零件时加工精度低、效率低和工序分散问题,为符合现代制造技术发展方向的车铣复合加工的推广和应用提供参考和借鉴。     

溢流壳车铣复合加工工艺研究

以溢流壳零件的加工为例,介绍车铣复合加工工艺,重点分析工艺过程的难点,有效解决普通数控加工高集成度零件时工艺分散、精度低、效率低等问题,为车铣复合加工工艺的推广和应用提供参考和借鉴。     

B0326-II双主轴走心车铣中心小型复合轴零件加工技术研究

介绍B0326-Ⅱ双主轴走心车铣中心在加工小型化、大批量、高复合轴类零件方面的独特优势,对小型复合轴零件技术要求、加工工艺、产品调试过程、试加工问题分析等方面进行了深入的研究,为双主轴走心车铣中心的推广应用和同类零件加工提供参考。     

Effects of Post-weld Heat Treatment on Microstructure,Mechanical Properties and the Role of Weld Reinforcement in 2219 Aluminum Alloy TIG-Welded Joints

In as-welded state, each region of 2219 aluminum alloy TIG-welded joint shows diff erent microstructure and microhardness due to the diff erent welding heat cycles and the resulting evolution of second phases. After the post-weld heat treatment, both the amount and the size of the eutectic structure or θ phases decreased. Correspondingly, both the Cu content in α-Al matrix and the microhardness increased to a similar level in each region of the joint, and the tensile strength of the entire joint was greatly improved. Post-weld heat treatment played the role of solid solution strengthening and aging strengthening. After the post-weld heat treatment, the weld performance became similar to other regions, but weld reinforcements lost their reinforcing eff ect on the weld and their existence was more of an adverse eff ect. The joint without weld reinforcements after the post-weld heat treatment had the optimal tensile properties, and the specimens randomly crack in the weld zone.     

The First Phase of the SRIF Industrialized Base in ＂West Area＂ Has Been Put into Operation

After nearly two years＇ tense construction, the first phase of industrialized base of Shenyang Research Institute of Foundry （SRIF）, located at the Tiexi Casting and Forging Industrial Park in the west of Tiexi District, has now been completed and formally put into operation.     

Thermodynamics Study on the Decomposition of Chromite with KOH

Institute of Process Engineering, Chinese Academy of Sciences, China, has proposed a method for oxidative leaching of chromite with potassium hydroxide. Understanding the mechanism of chromite decomposition, especially in the potassium hydroxide fusion, is important for the optimization of the operating parameters of the oxidative leaching process. A traditional thermodynamic method is proposed and the thermal decomposition and the reaction decomposition during the oxidative leaching of chromite with KOH and oxygen is discussed, which suggests that chromite is mainly destroyed by reactions with KOH and oxygen. Meanwhile, equilibrium of the main reactions of the above process was calculated at different temperatures and oxygen partial pressures. The stable zones of productions, namely, K2CrO4 and Fe2O3, increase with the decrease of temperature, which indicates that higher temperature is not beneficial to thermodynamic reactions. In addition, a comparison of the general alkali methods is carried out, and it is concluded that the KOH leaching process is thermodynamically superior to the conventional chromate production process.     

Influence of Heat Treatment on Damping Behaviour of the Magnesium Wrought Alloy AZ61

The effect of isochronal heat treatments for 1h on variation of damping, hardness and microstructural change of the magnesium wrought alloy AZ61 was investigated. Damping and hardness behaviour could be attributed to the evolution of precipitation process. The influence of precipitation on damping behaviour was explained in the framework of the dislocation string model of Granato and Lücke.     

Effect of Rare Earth Doping on Impedance,Modulus and Conductivity Properties of Multiferroic Composites:0.5(BiLa_xFe_(1-x)O_3)–0.5(PbTiO_3)

The Lanthanum-doped bismuth ferrite–lead titanate compositions of 0.5(Bi LaxFe1-xO3)–0.5(Pb Ti O3)(x = 0.05,0.10,0.15,0.20)(BLxF1-x-PT) were prepared by mixed oxide method.Structural characterization was performed by X-ray diffraction and shows a tetragonal structure at room temperature.The lattice parameter c/a ratio decreases with increasing of La(x = 0.05–0.20) concentration of the composites.The effect of charge carrier/ion hopping mechanism,conductivity,relaxation process and impedance parameters was studied using an impedance analyzer in a wide frequency range(102–106Hz) at different temperatures.The nature of Nyquist plot confirms the presence of bulk effects only,and non-Debye type of relaxation processes occurs in the composites.The electrical modulus exhibits an important role of the hopping mechanism in the electrical transport process of the materials.The ac conductivity and dc conductivity of the materials were studied,and the activation energy found to be 0.81,0.77,0.76 and 0.74 e V for all compositions of x = 0.05–0.20 at different temperatures(200–300 °C).     

Using Finite Element and Contour Method to Evaluate Residual Stress in Thick Ti-6Al-4V Alloy Welded by Electron Beam Welding

This work was to reveal the residual stress profile in electron beam welded Ti-6Al-4V alloy plates(50 mm thick) by using finite element and contour measurement methods.A three-dimensional finite element model of 50-mmthick titanium component was proposed,in which a column–cone combined heat source model was used to simulate the temperature field and a thermo-elastic–plastic model to analyze residual stress in a weld joint based on ABAQUS software.Considering the uncertainty of welding simulation,the computation was calibrated by experimental data of contour measurement method.Both test and simulated results show that residual stresses on the surface and inside the weld zone are significantly different and present a narrow and large gradient feature in the weld joint.The peak tensile stress exceeds the yield strength of base materials inside weld,which are distinctly different from residual stress of the thin Ti-6Al-4V alloy plates presented in references before.     

Microstructures and Tensile Properties of Ultrafine-Grained Ni–(1–3.5) wt% SiC_(NP) Composites Prepared by a Powder Metallurgy Route

Silicon carbide nanoparticle-reinforced nickel-based composites(Ni–Si CNP),with a Si CNPcontent ranged from1 to 3.5 wt%,were prepared using mechanical alloying and spark plasma sintering.In addition,unreinforced pure nickel samples were also prepared for comparative purposes.To characterize the microstructural properties of both the unreinforced pure nickel and the Ni–Si CNPcomposites transmission electron microscopy(TEM) was used,while their mechanical behavior was investigated using the Vickers pyramid method for hardness measurements and a universal tensile testing machine for tensile tests.TEM results showed an array of dislocation lines decorated in the sintered pure nickel sample,whereas,for the Ni–Si CNPcomposites,the presence of nano-dispersed Si CNPand twinning crystals was observed.These homogeneously distributed Si CNPwere found located either within the matrix,between twins or on grain boundaries.For the Ni–Si CNPcomposites,coerced coarsening of the Si CNPassembly occurred with increasing Si CNPcontent.Furthermore,the grain sizes of the Ni–Si CNPcomposites were much finer than that of the unreinforced pure nickel,which was considered to be due to the composite ball milling process.In all cases,the Ni–Si CNPcomposites showed higher strengths and hardness values than the unreinforced pure nickel,likely due to a combination of dispersion strengthening(Orowan effects) and particle strengthening(Hall–Petch effects).For the Ni–Si CNPcomposites,the strength increased initially and then decreased as a function of Si CNPcontent,whereas their elongation percentages decreased linearly.Compared to all materials tested,the Ni–Si CNPcomposite containing 1.5% Si C was found more superior considering both their strength and plastic properties.     

Directional Growth of Tin Crystals Controlled by Combined Solute Concentration Gradient Field and Static Magnetic Field

A new method was introduced to achieve directional growth of Sn crystals. Microstructures in liquid(Pb)/liquid(Sn) diffusion couples were investigated under various static magnetic fields. Results show that the β-Sn crystals mainly reveal an irregular dendritic morphology without or with a relatively low static magnetic field(B0.3 T). When the magnetic field is increased to 0.5 T, the β-Sn dendrites close to the final stage of growth begin to show some directional character. With a further increase in the magnetic field to a higher level(0.8–5 T), the β-Sn dendrites have an enhanced directional growth character, but the dendrites show a certain deflection. As the magnetic field is increased to 12 T, the directional growth of the β-Sn dendrites in the center of the couple is severely destroyed. The mechanism of the directional growth of the β-Sn crystals and the deflection of the β-Sn crystals with the application of static magnetic field was tentatively discussed.     

Quantitative Analysis of the Crystallographic Orientation Relationship Between the Martensite and Austenite in Quenching–Partitioning–Tempering Steels

The orientation relationships(ORs)between the martensite and the retained austenite in low-and medium-carbon steels after quenching–partitioning–tempering process were studied in this work.The ORs in the studied steels are identified by selected-area electron diffraction(SAED)as either K–S or N–W ORs.Meanwhile,the ORs were also studied based on numerical fitting of electron backscatter diffraction data method suggested by Miyamoto.The simulated K–S and N–W ORs in the low-index directions generally do not well coincide with the experimental pole figure,which may be attributed to both the orientation spread from the ideal variant orientations and high symmetry of the low-index directions.However,the simulated results coincide well with experimental pole figures in the high-index directions{123}_(bcc).A modified method with simplicity based on Miyamoto’s work was proposed.The results indicate that the ORs determined by modified method are similar to those determined by Miyamoto’method,that is,the OR is near K–S OR for the low-carbon Q–P–T steel,and with the increase of carbon content,the OR is closer to N–W OR in medium-carbon Q–P–T steel.     

Growth Kinetics of Single Inclusion Particle in Molten Melts

On the basis of the single-particle framework, a new theory on inclusion growth in metallurgical melts is developed to study the kinetics of inclusion growth on account of reaction and collision. The studies show that the early growth of inclusion depends on reaction growth and Brawnian motion collision, and where the former is decisive, the late growth depends on turbulence collision and Stokes＇ collision, and where the former is dominant; collision growth is very quick during the smelting process, lessened in the refining process, but nearly negligible in the continuous casting process.