Application of ultra-smooth composite diamond film coated WC-Co drawing dies under water-lubricating conditions

A specific revised HFCVD apparatus and a novel process combining HFCVD and polishing technique were presented to deposit the micro-and nano-crystalline multilayered ultra-smooth diamond（USCD） film on the interior-hole surface of WC-Co drawing dies with aperture ranging from d1.0 mm to 60 mm.Characterization results indicate that the surface roughness values（Ra） in the entry zone,drawing zone and bearing zone of as-fabricated USCD coated drawing die were measured as low as 25.7,23.3 and 25.5 nm,respectively.Furthermore,the friction properties of USCD films were examined in both dry sliding and water-lubricating conditions,and the results show that the USCD film presents much superior friction properties.Its friction coefficients against ball-bearing steel,copper and silicon nitride balls（d4 mm）,is always lower than that of microcrystalline diamond（MCD） or WC-Co sample,regardless of the lubricating condition.Meanwhile,it still presents competitive wear resistance with the MCD films.Finally,the working lifetime and performance of as-fabricated USCD coated drawing dies were examined under producing low-carbon steel pipes in dry-sliding and water-lubricating conditions.Under the water-lubricating drawing condition,its production significantly increases by about 20 times compared with the conventional WC-Co drawing dies.

Fabrication and application of nano/microcrystalline composite diamond coated drawing dies using alternative carbon sources

Nano/microcrystalline composite diamond films were deposited on the holes of WC-6%Co drawing dies by a two-step procedure using alternative carbon sources, i.e., methane for the microcrystalline diamond（MCD） layer and acetone for the nanocrystalline diamond（NCD） layer. Moreover, the monolayer methane-MCD and acetone-NCD coated drawing dies were fabricated as comparisons. The adhesion and wear rates of the diamond coated drawing dies were also tested by an inner hole polishing apparatus. Compared with mono-layer diamond coated drawing die, the composite diamond coated one exhibits better comprehensive performance, including higher adhesive strength and better wear resistance than the NCD one, and smoother surface（Ra=65.3 nm） than the MCD one（Ra=95.6 nm） after polishing at the same time. Compared with the NCD coated drawing die, the working lifetime of the composite diamond coated one is increased by nearly 20 times.

Wear Characteristics of Zirconia Toughened Ceramic Drawing Dies

Wear resistance of several zirconia toughened ceramics in comparison with a metal-ceramic Co-WC has been studied in drawing wire field test. Result indicates that the harder the ceramic die, the longer the service life. Excellent wear resistance of ceramic die is obtained with a very high hardness (19 GPa). The service life is nearly three times that of Co-WC die. SEM observation on wear surfaces showed that material removal is mainly caused by plastic flow and ploughing process. But when the ceramic is composed of zirconia, alumina and some titanium carbide, micro-chipping and tribochemical reaction take place, and wear rate increases. Wear and friction induced martensite was detected by XRD. The T-M (tetragonal to monoclinic) phase transformation has a contribution to inhibiting microfracture.

THE CURVILINEARINTEGRAL PROBLEMS TO VELOCITY FIELD FOR DRAWING THROUGH PARABOLIC DIES

n this paper with Von Karmanis basic assumptions a kinematically admissible continuous velocity field has been established to drawing through parabolic dies (or called trumpet dies). Then by. using the curvilinear and the integral as a function of the upper limit an upper bound analytical solution of the drawing stress is obtained.

Advanced simulation of die wear caused by wire vibrations during wire-drawing process

An advanced simulation that considers the effect of wire vibrations was proposed for predicting accurately wear profiles of a die used in a wire-drawing process.The effect of wire vibrations,the changes in the wear profiles,and the generation of ringing during die approach were investigated by this simulation.Wire vibrations occurring between the die and the drum are governed by a partial differential equation called the wave equation,which is a function of the wire length,tension,density,and initial wire velocity.The wire-drawing process was simulated by the commercial code Abaqus FEA,and the die wear profiles were predicted by Archard’s wear model.The predicted profiles were compared with measured profiles of a worn drawing die after producing 5 t of AISI 1010 wire;the die was made of tungsten carbide with a Brinell hardness of HB 682.The profiles predicted by considering the effect of wire vibrations are in good agreement with the experimental data,indicating that the advanced simulation can be used to accurately predict the die wear profiles when ringing is observed during die approach.

Deep Drawing Process Using a Tractrix Die for Manufacturing Liners for a CNG High-Pressure Vessel(Type Ⅱ)

The liner of a CNG pressure vessel is manufactured by a DDI(deep drawing and ironing)process for the cylinder part,which is a continuous process that includes a drawing process to reduce the diameter of the billet and a subsequent ironing process to reduce the thickness of the billet.A tractrix die used in the 1^(st) deep drawing allows the blank to flow smoothly by decreasing the punch load and radial tensile stress occurring in the workpiece.It also increases the draw ratio compared to conventional dies,but it causes forming defects.In this study,a shape coefficient(S_(c))is proposed for the tractrix die using the blank diameter(D_(0)),inflow diameter of the workpiece(d_(i)),and inflow angle of the workpiece(θ)for design of the tractrix die.The effects of the thickness and inflow angle of the workpiece on wrinkling and folding were investigated through FEA.Also,a discriminant is proposed for the relative radial stress(σ)generated during the deep drawing process using the tractirx die and used to predict fracture.Based on the results,the blank thickness,the draw ratio,and the inflow of the workpiece angle in the 1^(st) deep drawing process are suggested,and the number of operations in the DDI process was reduced from 6 to 4.This improves the productivity and reduces the manufacturing cost.

Effect of die cavity dimension on micro U deep drawing behaviour with T2 foil

The strips U deep drawing experiments were carried out to study the effect of die cavity dimension with an extension machine manufactured by SANS company. The effects of parameters were analyzed in deep drawing process under different experimental conditions, such as punch load, reduction of thickness, angle of U part and surface quality. The experiment results show that the punch load increases with the decrease of female radius, and larger blank holder force enlarges the range of increasing. With the increasing of blank holder force, the angle of U part increases, and the reduction of foil thickness at the corner becomes larger. Obvious scratch and accumulation at the die cavity corner were observed by SEM. The investigation results indicate that micro U deep drawing of foil is affected by micro die cavity dimension.

Effect of Anisotropy,Temperature,Strain Rate on Deep Drawing Using Conical Die

This paper covers the role of anisotropy,temperature,and strain rate on the flow behavior of the material when a conical die is used instead of conventional blank holder.The effect of anisotropy was investigated using Lankford’s coefficient(r)in three directions(0°,45°,and 90°).The effect of working temperatures(Room temperature,100°C-300°C)on drawing stress and strain rate sensitivity on punch pressure were also investigated in detail.ANSYS APDL was used to investigate the effects of temperature,strain rate and anisotropy.The simulation results have confirmed that the strain variation in the direction of r0 and r45 are more than the variation of r90.

Determination of a Drawing Die's Cone Angle at a Small Compression Ratio Based on the Upper Bound Theory

The value of a drawing die＇s cone angle has great influence on wire drawing. In order to determine the optimum value of a drawing die＇ s cone angle, the plastic deformation power Wi, shear deformation power Wi and friction power of contact surface Wf were calculated using the upper bound theory with a reasonable and movement permitted velocity field according to the related characteristics. Then the relation between half cone angle and unit drawing force was obtained and it was compared with the result with the spherical velocity field. The relative error of the two near the optimal value is only about 0. 26% through comparing with existing calculated results. Finally, in an ABAQUS environment the finite element modal of the wire rod with 12. 5 mm diameter in first drawing pass was established and the axial drawing force in different cone angles was obtained using the ABAQUS/Explicit explicit integration method. The finite element method （FEM） results verify the results using the upper bound theory and this indicated that the velocity field and the relation between half cone angle and unit drawing force reasonable.

Development on Technique of Tube Reducing in Double 3-Roll Dies

Based on the experiments, a new technique of reducing tube with two linked 3-roll roller dies was developed. The external friction conditions, velocity and the non-uniform deformation of metal were distinctly improved, and the friction between metal and tool was decreased. Corrosion strip layers and photo-elastic coatings methods were adopted in the experiment for measuring residual stress, and the residual stresses in the drawn tube with 3-roll dies are reduced.

基于板料冲压成形仿真系统FASTAMP-NX10与冲压模具智能设计系统SIS-V2.0的拉伸模设计

以电子产品金属外壳为实例,具体分析了其成形特点,找出某电子产品金属外壳冲压件成形的共性。介绍了电子产品金属外壳的成形特点和外壳件冲压模具设计的基本原则,其中包括了冲压方向、工艺补充面等设计的常用手法。直接用工业三维软件NX10.0构造出外壳冲压模具的三维实体模型,完成了电子产品金属外壳的模具设计,更真实的反映了模具零件之间的装配关系,减少了实际模具设计带来的一些问题和制造时间。同时,模具各部分的干涉检查能够方便地做到,从而提高了电子产品面壳模具结构的设计效率和质量,缩短了模具的设计和制造时间,这对制造业尤其是模具的制造来说尤为重要。

利用Pro/DIEFACE优化汽车覆盖件拉深模的拉深方向

从汽车覆盖件拉深模拉深方向的设计现状谈起 ,分析了目前拉深方向仅凭经验设计无法进行优化的两个主要原因 :拉深方向的判别指标无法实际应用和拉深方向的难以改变 ,进而结合Pro/Engineer中的专业模块Pro/DIEFACE所提供的设计和分析功能 ,讲述了如何利用Pro/DIEFACE将这两个问题合理地解决 ,从而实现了拉深方向的优化。

Design, Fabrication and Experimentation of a Deep Drawing Machine

This paper presents the work implemented in designing, fabricating and operating a model of a cheap hydraulic DDM （deep drawing machine）, which is currently utilized in the manufacturing processes lab in the IED （Industrial Engineering Department） at An-Najah National University. The machine is used to conduct different experiments related to the deep drawing process. This work was implemented in three stages： the first was the design stage, in which all design calculations of the DDM elements were completed based on the specifications of the product （cup） to be drawn; the second was the construction stage, in which the DDM elements were fabricated and assembled at the engineering workshops of the university; the last was the operating and experimentation stage, in which the DDM was tested by conducting different experiments. The experience gained from designing and constructing such a mechanical lab equipment was found to be successful in terms of obtaining practical results that agree with those available in literature, cost-effective relative to the cost of a similar purchased equipment, as well as enhancing students＇ abilities in understanding the deep drawing process in particular and machine elements design concepts in general.

钛合金薄壁构件快速加热冷模热冲压成形技术进展

为了解决钛合金薄壁构件热成形效率低、成本高、组织性能控制难度大等问题,近年来钛合金冷模热冲压成形技术受到关注。在该新技术中利用室温模具对加热后的钛合金板材进行快速冲压成形和模内快速冷却,由于取消了模具加热,可以变革性地提高钛合金薄壁构件成形效率、降低成本。然而,与传统等温成形不同,在冷模热冲压成形过程中,钛合金板材温度不断下降,这对钛合金成形极限、回弹及组织性能等的控制提出了全新的挑战。分析了钛合金薄壁构件冷模热冲压成形技术特点及存在的问题,归纳了快速加热对钛合金组织性能的影响规律,综述了钛合金薄壁构件快速加热冷模热冲压成形工艺进展,最后对该技术未来的发展方向进行了展望。

火锅菜盆复合模设计

根据火锅菜盆的尺寸、结构和材料厚度,对其冲压工艺进行分析,并设计了“落料+第1次成形+拉深”复合模、第2次成形单工序模、侧冲孔单工序模。在复合模中,120°的斜边可视为拉深工序的压边圈,将第1次成形120°夹角的工序排在拉深工序前。在第2次成形70°夹角的单工序模的下模中设计了活动顶板,与上模的成形凸模将120°的斜边压住,防止120°的斜边变形。在“落料+第1次成形+拉深”复合模和第2次成形单工序模中,在下模成形零件的底部设置橡胶垫块,在上模向下运动时橡胶垫块的弹力将材料顶住,同时给上模向下运动腾出空间,防止模具零件卡死。

高压线束支架多工位连续模设计

该文分析高压线束支架的冲压成形工艺及排样方法,阐述该连续冲裁模的结构及工作零件的加工方法,凹模采用镶拼结构,节约模具钢,零件加工难度降低,制造成本降低。实践证明,该模具结构合理,冲件质量稳定,较好地满足冲件精度和批量生产的要求。

基于“PBL+云平台”的《冲压工艺与模具设计》课程改革探索与实践

模具制造技术专业的核心课程《冲压工艺与模具设计》正受到授课内容布置、教学实施、成绩评估等方面的限制,随着互联网技术与教育的融合,以平台规划、学情分析及教学评价为突破口,基于云平台建设了《冲压工艺与模具设计》在线课程,并以PBL模式实施教学,实现了资源与知识点匹配衔接,形成了既能合理运用资源实施多种方法授课,又会创作资源的创新型课程教学团队,助推人才培养质量。

高速钢桶焊缝机电机座支撑脚复合模设计

针对高速钢桶焊缝机电机座支撑脚使用2 mm厚的SECC板料进行中小批量冲压成形的要求,设计了3副模具用于制件的4道工序成形。冲孔落料和修边压印采用倒装式复合模结构、切分模和弯曲模采用正装结构,且切分模和弯曲模集成在1副模具内。弯曲模中设计了凸模驱动的双滑块内收弯曲成形机构,该机构在制件弯曲壁的两侧都使用滑块进行夹紧驱动弯曲,能有效防止弯曲回弹,保证了制件的弯曲成形尺寸。模具结构简单实用,成形工艺设计合理,实现了制件的自动化生产。

“双高计划”背景下高职“冲压模具设计”教材改革与实践

为提升高职教育“模具设计与制造技术”高素质技术技能人才培养质量,以“冲压模具成形工艺与设计”课程建设与教材改革为研究对象,遵循项目导向、任务驱动、理实一体相结合的原则,创新“冲压模具设计”教材的人才培养策略与教材体系内容,突出能力本位的职业教育改革思想和思政教育理念。通过教材改革与实践,有效激发了学生的学习兴趣,培养了实践能力与创新思维,提升了冲压模具设计的自信心,提高了教学质量。

一种锁芯片零件加工连续级进冲压模具的设计分析

为了实现锁芯片零件的全自动化加工,针对一种锁芯片零件,设计了一种连续级进冲压加工模具,解决了该零件打凹、冲孔及落件多道工序的加工问题,并且大大提高了该零件生产的自动化程度、生产效率及加工精度。