对冲裁模第三类尺寸标注的探讨

<正> 间隙对冲裁面质量及冲裁尺寸精度都有影响。如果冲裁间隙合理,此时被冲材料在凸凹模刃口处的裂纹互相重合。这样,卸料力和推料力较小,模具寿命也可以延长,冲床也不易损坏。因此,我们应当在冲裁间隙的问题上尽量做到合理。 冲裁模凸、凹模刃口尺寸计算与标注是     

控制电机冲裁模凸凹模间隙的几种工艺方法

冲模(冲裁或冲孔)的凸凹模之间,应保持一定的间隙值。间隙的大小取决于被冲裁材料的厚度及其机械性能。间隙值的合理选择、模具装配及使用时对凸凹模间隙的控制是否均匀(如间隙分布不均匀,会使工件产生单面毛刺)都直接影响工件表面质量和尺寸精度,而且也影响冲裁力、脱粒力和模具寿命。因此,正确的控制间隙具有很大的工艺意义。     

冲裁模刃口公差对冲裁间隙影响的公差分析

冲裁间隙是影响冲裁断面质量和模具寿命的重要参数,选择合适的冲裁间隙对两者来说其重要性不言而喻,而保证合理的冲裁间隙值取决于冲裁模刃口尺寸及其制造公差。分析了传统凹、凸模刃口尺寸及其制造公差计算的不足之处,以凹模刃口尺寸公差为增环、凸模刃口尺寸公差为减环以及冲裁间隙为封闭环,验证了冲裁模具刃口尺寸及其制造公差对冲裁间隙的影响,从而保证冲裁时合理间隙值。新改进的方法简化了冲裁模刃口尺寸的计算过程,并使得冲裁件的尺寸公差更加接近尺寸中间值,同时确保了合理冲裁间隙值。在一般情况下,新改进的方法可以较好地保证冲裁过程中冲裁间隙值。     

冲裁模间隙及其对冲片质量和模具寿命的影响

在冲裁模的设计中 ,凸凹模间隙的合理选取 ,是保证模具正常工作、提高冲片质量、延长模具寿命的一个关键因素。理想的间隙应该是板料冲裁断裂时 ,凸凹模刃口边所产生的裂纹在一条直线上 ,否则冲片边缘将出现不允许的毛刺 ,使得刃口粘结严重 ,磨损加快 ,进而影响模具的寿命。所以 ,如何选取合理的凸凹模间隙 ,是模具设计时不容忽视的问题。　　通常情况下 ,模具设计中间隙一般都按设计手册推荐的间隙值选取。例如 ,我厂电机定、转子片为0 .5ｍｍ的硅钢片 ,手册推荐的间隙为 0 .0 4～0 .0 7ｍｍ ,约为材料厚度的 8%～ 1 4%。按照这个间隙 ,冲…     

提高厚钢板小孔冲裁质量的工艺参数优化

为提高10钢厚板小孔(t/d≥1、t4 mm)的冲裁质量,研究厚板冲裁工艺参数材料厚度t、冲裁小孔直径d、凸凹模间隙c及摩擦因子m对冲裁成形质量的影响规律。通过数值模拟和正交试验设计相结合研究发现:影响相对光亮带长度最大的因素是凸凹模间隙,其次是板料厚度和小孔直径,摩擦因子的影响程度较弱;相对光亮带长度随着凸凹模间隙的增大而先增大后减小,随着板料厚度的增加而增加,随着小孔直径和摩擦因子的增加并未有较大的变化。综合分析,为了提高冲裁质量,优化的厚径比为1.1~1.5,凸凹模间隙选用(5%~10%)t。通过生产试验,模拟结果与试验结果相一致,冲孔成形质量好。     

微电机壳装配基准面的光洁冲裁模设计

从微电机壳端面加工工艺的分析入手，基于光洁冲裁原理，设计了一套微电机壳装配基准面的光洁冲裁模，并介绍了该模具的工作过程。详细阐述了光洁冲裁凹模、压边圈等重要零件的结构设计与选材，并对光洁冲裁间隙进行了分析和选择。经使用，工件端面光洁而无毛刺、模具使用寿命高。     

矿山机械皮带辊轮罩用08F钢冲裁间隙对断面影响的研究

冲裁加工中间隙值的选定尤为重要,间隙值选定的是否合理,对冲裁件断面毛刺高度、断面光亮带宽度、断面倾斜角度和冲裁件尺寸精度有着极其重要的影响。对南京唐亿精密机械公司的拉深产品08F钢板的下料间隙选定进行试验,通过固定凹模尺寸,改变凸模尺寸,获得了5组不同的间隙后进行冲裁。并分析了不同间隙下产品的尺寸精度、毛刺高度和光亮带宽度,找出间隙对产品断面质量的影响规律。实验结果表明,将间隙值从原来的0.15 mm(即板料厚度的6%)增加到0.3 mm(即板料厚度的12%)后进行冲裁,工件断口的毛刺高度降低,基本稳定在0.03~0.04 mm,光亮带比例适中,断面倾角小,产品尺寸稳定,降低了废品率,提高了模具寿命。     

面板斜刃冲裁模设计

详细介绍了面板斜刃冲裁模的设计方法和模具结构及冲裁凸凹模结构.     

高精度内形光洁冲裁的模具设计

<正> 现行内形光洁冲裁方法有三种成功的工艺方案:①内形整修②光洁冲裁③精密冲裁。精密冲裁由于受设备及模具设计制造技术水平的限制,很多中小型企业和乡镇企业很难采用。内形整修是先冲留有一定余量的孔,经过一次或多次整修来达到工件尺寸精度、表面粗糙度。缺点是工序多,增加了工时和模具费用。光洁冲孔是一种新的冲裁方法,冲裁后的断面光洁程度较高,但关于模具的设计一般资料介绍较少,本文从间隙与冲裁断面关系和金属流动特点入手,浅析这种高精度光洁冲孔模具的设计。     

聚氨酯冲裁模设计与应用

用常规钢制冲模冲裁薄板零件 ,冲裁断面常有毛刺。聚氨酯冲裁模能自动调整间隙 ,用1副模具可冲制不同厚度的薄片零件 ,制件平整光洁、无毛刺 ,模具结构简单、制造容易 ,适于薄板冲裁。     

新型的治疗阿尔茨海默氏症药物(1-二甲基磷酰基-2,2,2-三氯)-乙基-1-醇烟酸醋对体外神经细胞的作用

目的: 观察本实验室合成的一种治疗阿尔茨海默氏症(AD)的药物(1-二甲基磷酰基-2, 2, 2 -三氯)-乙基^-1-醇烟酸醋(NMF),对体外培养的皮层神经细胞活性的影响以及对海人藻酸(KA)所致的神经损伤的保护作用。方法: 采用体外培养皮层神经元的方法,解剖分离 15 d胚胎小鼠皮层神经细胞, 接种于 96孔板,48 h 后加药并培养 72 h,以 MIT 法 观察 NMF 对小鼠皮层神经细胞活性的影响;同时将接种于 24 孔板的细胞预先给予 NMF,d 3 时加或不加KA处理后,以台盼蓝染色鉴别并计数死、活细胞,可得出细胞的存活率。结果: NMF 明显促进胎鼠皮层神经元活性,其中 NMF1、0. 1、10nmol·L^-1促进神经元活性增殖率分别高达 34.7%、37.4%、36. 7%, NMF 明显促进正常胎鼠皮层神经元存活卒,与对照组比较,10nmol·L^-1 NMF 对皮层神经元的存活率分别提高 39.3%、73.5%。 NMF能显著 对抗 KA 所致的神经元损伤,与 KA 损伤组相比, NMF0.1、10、10nmol·L^-1对损伤皮层神经元的保护率分别为 77.30%、80.10%、84.15%。结论: NMF 明 显促进胎鼠皮层神经元的洁性、提高正常皮层神经元,的存活卒,并能有效地保护KA所致的神经元损伤,提示 NMF 是一种很有潜力的治疗 AD 的药物。     

Three-Dimensional Growth of Coherent Ferrite in Austenite: A Molecular Dynamics Study

Coherent second phase often exhibits anisotropic morphology with specifi c orientations with respect to both the second and the matrix phases. As a key feature of microstructure, the morphology of the coherent particles is essential for understanding the second-phase strengthening eff ect in various industrial alloys. This letter reports anisotropic growth of coherent ferrite from austenite matrix in pure iron based on molecular dynamics simulation. We found that the ferrite grain tends to grow into an elongated plate-like shape, independent of its initial confi guration. The fi nal shape of the ferrite is closely related to the misfi t between the two phases, with the longest direction and the broad facet of the plate being, respectively, consistent with the best matching direction and the best matching plane calculated via the Burgers vector content(BVC) method. The strain energy calculation in the framework of Eshelby's inclusion theory verifi es that the simulated orientation of the coherent ferrite is energetically favorable. It is anticipated that the BVC method will be applicable in analysis of anisotropic growth and morphology of coherent second phase in other phase transformation systems.     

Effect of Short-Time Aging on the Pitting Corrosion Behavior of a Novel Lean Duplex Stainless Steel 2002

The effect of short-time aging in the temperature range between 400 and 1000 °C on the pitting corrosion behavior and mechanical property of a novel lean duplex stainless steel(LDSS) 2002 was investigated through the potentiostatic critical pitting temperature(CPT) tests and the Charpy impact tests. Both the pitting corrosion resistance and the toughness of aged specimens degraded due to the precipitation of detrimental secondary phases and the most significant reduction of CPT and impact energy emerged at 650 °C concurrently. The CPT of LDSS 2002 specimen aged at 650 °C decreased by 28 °C, and the impact energy dropped from 69 to 29 J/cm~2 compared with the solution-annealed sample. Transmission electron microscopy characterization showed that the main precipitates in LDSS 2002 were Cr_2N and M_(23)C_6 along the ferrite–austenite grain boundaries.     

Information for Contributors

正The Transactions of Nonferrous Metals Society of China,founded in 1991 and sponsored by The Nonferrous Metals Society of China,is published monthly now and mainly contains reports of original research which reflect the new progresses in the field of nonferrous metals science and technology,including mineral processing,extraction metallurgy,metallic materials and heat treatments,metal working,physical metallurgy,powder metallurgy,with the emphasis     

Preface

<正>We are pleased to present this Special Issue of Transactions of Nonferrous Metals Society of China containing selected papers from the First Asian Conference on Aluminum Alloys(ACAA-2013),held in Beijing,China,13–17 October 2013.This conference has been initiated,with approval of     

Information for Contributors

The Transactions of Nonferrous Metals Society of China, founded in 1991 and sponsored by The Nonferrous Metals Society of China, is published monthly now and mainly contains reports of original research which reflect the new progresses in the field of nonferrous metals science and technology, including mineral processing, extraction metallurgy, metallic materials and heat treatments, metal working, physical metallurgy, powder metallurgy, with the emphasis on fundamental science. It is the unique preeminent publication in English for scientists, engineers, under/post-graduates on the field of nonferrous metals industry. This journal is covered by many famous abstract/index systems and databases such as SCI Expanded, Ei Compendex Plus, 1NSPEC, CA, METADEX, AJ and JICST.     

INTRODUCTION TO PATENTS

The invention provides a method of making a mold which can reduce SOx generation rate while preventing decrease in hardening rate in the case of using sulfuric acid for a hardener composition. The method has a mixture step in which fire-resistant particles, a hardener composition and a binder composition are mixed to obtain a composition for a mold. The hardener composition contains sulfuric acid. In the mixture step, sodium carbonate is added. A molar ratio of the sulfuric acid to the sodium carbonate is 0.5 or more and 4.0 or less.     

China Foundry Week 2014

China Foundry Week, hosted by the Foundry Institution of Chinese Mechanical Engineering Society （FICMES） each year, is a large academic event in China. It is one of the ten high-impact activities sponsored by the Chinese Mechanical Engineering Society.     

17th Conference of Hydrodynamic and Electromechanical Control Engineering Call for papers

正1.Contents In order to promote the academic exchanges and technical communication of the research in the field of fluid power transmission and control,fluid control engineering specialized committee of the Chinese Society of Theoretical and Applied Mechanics will hold the 17th Conference of Hydrodynamic and Electromechanical Control Engineering on July 27-29,2014 in Tibet,Lhasa city.     

Formulas of Tension of Continuous Rolling Process

The development of computer controlled continuous rolling process calls for a mathematical expression that can express the inequality condition of "constant flow". Tension is the link of the continuous rolling process. From the condition of dynamic equilibrium, a differential equation of tension is given out. On the basis of the physical rules established from the industrial practice and experimental studies, the law of volume constancy, the linear relation of forward slip and tension, the state equation of continuous rolling, the formula of dynamic tension, and the formula of static tension have been obtained. These formulae reflect the functional relations between tensions, thickness, roll velocity, and time in the continuous rolling process. It is implied that the continuous rolling process is a gradually steady, controllable, and measurable dynamic system. An assumption of predicting the thickness of a steel plate using these tension formulae is also put forward.