磨料流加工技术在热流道模具制造中的应用

为了解决模具热流道板的超细长流道孔及放射状细长热流道群孔的抛光和交叉孔去毛刺问题,首次将磨料流加工技术用于模具热流道的抛光。通过实例,介绍了加工工艺参数的选择或确定方法,指出了夹具设计要点,用图像比较的方法检测加工表面粗糙度值。实践证明,加工几分钟即可达到技术要求,其优越性在于抛光和去毛刺同时完成,抛光均匀性好、彻底去除了交叉孔的毛刺、加工效率高。该技术的高精度、高效、经济等特点为热流道模具的快速高精度制造提供了强有力的技术支持。     

微磨料水射流加工脆性玻璃的冲蚀机理研究

微磨料水射流加工技术正成为制造微细结构零件重要的经济高效的微细加工技术。作者在玻璃上进行微磨料水射流微细槽加工的实验基础上,对微磨料水射流加工的表面形貌、材料冲蚀去除机理及加工工艺性能进行了研究。结果表明,玻璃加工表面沿着槽道的方向形成了波纹状形貌,呈非对称或对称的波形,波纹表面很光滑,波纹图案沿着射流冲击区的径向方向发展。由于黏性流体的阻滞作用,脆性玻璃在微磨料水射流加工过程中,在黏性流区域没有发现任何裂纹,材料的冲蚀去除主要是以塑性断裂的方式为主,形成了光滑的加工表面。适当地控制加工工艺参数,在低压下,微磨料水射流加工是一种用于脆性材料上微细通道的加工切实可行的方法,并可获得良好的加工表面质量。     

磁粒研磨镍基高温合金群孔切出毛刺的研究

为解决镍基高温合金GH3128群孔切出毛刺难去除的问题,基于磁粒研磨法开展毛刺去除试验研究。对镍基高温合金GH3128钻孔加工后孔缘毛刺进行分类,基于磁粒研磨法分析典型毛刺去除机理,并提出群孔毛刺去除的研磨轨迹和磁极形状初步方案。开展磁粒研磨群孔试验研究,分析主轴转速和磨粒平均粒径对切出毛刺去除的影响。结果表明:在主轴转速为1 500 r/min、磁性磨料平均粒径250μm、进给速度2 mm/s、磁性磨粒填充量30 g、加工间隙2 mm的加工条件下,研磨40 min后,群孔切出毛刺平均高度由原始的141μm降至20.5μm,毛刺的平均宽度从原始350μm降至163μm。规划研磨轨迹、磁极开矩形槽以及优化研磨参数的方法,使镍基高温合金GH3128群孔切出毛刺得到了很好的去除,此加工方案可为群孔切出毛刺的去除提供参考。     

精密零件的微磨料气射流光整加工

近年来,在非传统去毛刺加工方法中,微磨料气射流去毛刺由于初始成本低、生产效率高、灵活性强、无应力、无热影响区,在精密零件的光整加工中获得了广泛的应用。本文详细介绍了微磨料气射流用于光整加工去毛刺的加工原理、材料去除机理、去毛刺的工艺参数以及对棱边尺寸的影响,并列举了一些微磨料气射流在不同应用领域的加工实例。     

YB叶片泵转子槽去毛刺机

YB型中低压叶片泵是我厂生产的产品之一,长期来,为了提高叶片泵的质量,我们对该泵做了大量的工艺实验与技术探讨。其中就转子加工后如何有效的清除槽内、外毛刺的这一问题始终没有得到很好的解决。以前在装配时都是用手工的方法来修理转子槽的毛刺,(工具是用三角油石)这样既浪费时间,槽的毛刺又修理不干净,有时槽的毛刺还漏修,同时也破坏了转子槽的几何形状。常因转子槽毛刺清修不干净而引起油泵噪音、磨损加快、咬死等现象发生。由于转子槽的毛刺修理不干净,严重地影响了油泵的质量和使用寿命。     

超声辅助磨料流加工的材料去除机理及参数研究

超声辅助磨料流加工是将超声加工与磨料流加工结合在一起的新型光整加工技术。为了进一步提高超声辅助磨料流的加工精度和加工效率,从材料去除机理的角度出发,建立了单磨粒的力学模型。通过Box-Behnken响应面实验对影响表面质量和加工效率的重要参数进行了研究。结果表明:与传统的磨料流加工相比,超声辅助磨料流获得了更好的表面质量和更快的加工速度;材料去除量和表面粗糙度变化率受超声频率扰动的影响最大;在一定范围内,随着超声频率的增大,表面精度先提高后降低,加工效率则不断提高。     

磨料流加工研究进展

磨料流加工是表面加工中发展起来的一项新工艺，是通过将半固态的流体磨料挤压通过工件待加工表面来达到去毛刺，抛光、倒角和去除再铸层的目的。本文介绍了磨料流加工的基本原理，影响磨料流加工的因素，当前磨料流加工的应用现状及加工设备，磨料流加工的研究成果和最新进展，磨料流加工与其它工艺的结合情况。并总结了磨料流加工的主要结论。     

磨料流加工中夹具设计的研究

磨料流加工(AFM)是光整加工领域的一项新技术。磨料流加工由磨料流加工机床,夹具和流体磨料三部分组成。当用磨料流加工形状较复杂的零件时,夹具设计的好坏对表面加工质量和加工效率有重要的影响。本文分析了磨料通过工件孔道的特性。介绍了用于研究材料去除量与加工距离和形状关系的实验。材料去除量在通道两端比中间小是磨料流加工的一基本特性。本文讨论了如何避免因此而产生的工件变形以及如何利用这一特性来获取某种特殊效果。最后,给出了一个用于加工某不锈钢三通体的夹具。     

磨料珩磨刷的应用与改进

对于铸铁零件其内孔精加工后又在其径向方向加工顶丝孔如图1所示,在加工顶丝孔的底孔及攻丝时其内孔都将出现较大的毛刺,其高度一般为0.10～0.85mm,这样在装配工序中将出现两种情况:其一,将划伤与孔相配的旋转轴,其二,因毛刺较大旋转轴无法装配。因此必须清除毛刺而且不能影响精加工后的内孔尺寸精度及表面光洁度,在此前提下清理内孔毛刺最简单、可靠的方法是采用美国专利US8,871,189所提供的孔加工工具——磨料珩磨     

粘弹性介质的磨料流加工

用含磨料的高分子树脂对难加工表面如盲孔、内部交错孔等进行磨料流加工,可顺利完成去毛刺、倒圆角、表面精饰等。文中给出了磨料粒度、介质等的选择。     

Burr minimizing scheme in drilling

In conventional drilling, burr formation can be changed by varying the drill’s geometry, i.e. the step angle and point angle. To minimize burr formation, it is proposed that a step drill be used. The step drill performs front edge cutting before step edge cutting. The burr formed in first cutting by front cutting edge can be removed in second cutting by step edge. In particular, new burrs are formed through the second cutting. They can be minimized by changing the drill’s geometry. A laser sensor is used to measure the burr formed in the drilling.     

冲裁毛刺对疲劳寿命影响的数值仿真分析

由于冲裁毛刺对疲劳性能具有很大的影响,运用线弹性模型对止动弹簧片冲裁毛刺进行数值仿真模拟,提出一种考虑冲裁毛刺对疲劳性能影响的疲劳计算方法。通过定量计算毛刺对零件结构几何边界应力的影响程度,得出因冲裁毛刺影响而造成的应力集中程度;综合材料应力-寿命曲线与载荷谱,运用疲劳积累损伤理论计算出零件的疲劳寿命;在数值仿真分析中计算出添加毛刺与未添加毛刺单元的零件疲劳寿命。通过实验对零件的疲劳寿命计算值进行对比分析验证,结果表明:定量考虑冲裁毛刺对结构的影响能够提高疲劳寿命的计算精度。     

微细铣削铝合金6061表面毛刺研究

目的揭示微细铣削铝合金6061过程中,铣削工艺参数(切削深度a_p、每齿进给量f_z、切削速度v)、顺逆铣方式、刀具磨损对毛刺大小及形态的影响规律,为控制铝合金6061毛刺,提高表面质量,优化切削工艺提供参考。方法基于单因素试验方法,采用涂层硬质合金微直径铣刀,对铝合金6061进行了铣削加工试验,分别对切削参数单因素试验的逆铣、顺铣顶端毛刺大小数据以及刀具磨损、毛刺形态信息进行采集和分析。结果直观绘制了a_p、v、f_z对逆顺铣两侧顶端毛刺大小的影响规律图。单因素切削速度试验中,顺铣侧毛刺最大为323μm,逆铣侧最大为268μm;单因素每齿进给量试验中,顺铣侧毛刺最大为332μm,逆铣侧最大为331μm;单因素切深试验中顺铣侧毛刺最大为314μm,逆铣侧最大为264μm。结论逆铣比顺铣的顶端毛刺小,随切削深度增加,毛刺依次呈现长条须状、撕裂状、波浪形锯齿状。刀具磨损是造成切削过程不稳定的重要因素,同时也会造成毛刺形态和大小不稳定。为尽量减少毛刺,应采用锋利刀具和逆铣方式,控制切削深度,选择合适的切削速度和进给量。     

电化学对微小孔毛刺去除的仿真及试验

钻削微小通孔产生的孔口毛刺严重影响了其表面质量,且微小孔因直径小导致其入口和出口毛刺去除困难,为此提出基于电化学的微小通孔双面毛刺的同步去除方法。以0.35 mm厚的304不锈钢板的钻孔毛刺为研究对象,建立电化学毛刺去除仿真模型,分析电流密度与微小孔不同区域材料去除速率间的对应关系,研究电极位置及工艺参数对毛刺去除效果的影响,并开展相关试验研究。结果表明,孔口表面电流密度大小表征了材料去除能力的强弱,毛刺尖端电流密度大,孔内壁电流密度小且分布均匀;电极位置对出口毛刺去除速率影响大,伸出型电极毛刺去除效果最好;随加工电压、电解质浓度及电极直径增大,毛刺去除效率增高,但扩孔率增大,且电极直径越大入口倒角越明显;试验基于伸出型电极位置,采用4 V加工电压、12%NaNO₃电解质、0.2 mm电极半径,实现了孔口毛刺的精准去除,加工后的倒角宽度为38μm,扩孔率仅1.99%,验证了仿真的准确性。研究结果可为微小通孔双面毛刺的高效、精准去除奠定研究基础。     

Burr Formation in milling with minimum quantity lubrication

In milling, burrs are formed on entry and exit edges of the workpiece to be machined like in all material removal processes. In the subsequent production these burrs have to be removed. Understanding the influencing factors and burr formation mechanisms can help to avoid or reduce burrs. Another possibility for saving costs is to reduce the process materials, for example, cutting fluids. This can be realised by using minimum quantity lubrication or dry machining. The investigations show which influence both methods have on burr formation.     

航空航天铝合金构件装配孔钻削出口毛刺研究进展

航空航天制造业中存在大量的铝合金装配孔加工需求。装配孔主要通过钻削加工实现,加工中存在铝合金出口毛刺过大的问题。出口毛刺直接影响工件的精度、抗疲劳强度、装配性能,去毛刺工序会极大地增加工时和成本。因此有必要对铝合金装配孔钻削出口毛刺进行研究,实现对出口毛刺的控制。从铝合金钻削出口毛刺的类型和测量方法、形成机理和高度预测以及毛刺控制方法等方面进行了系统性的论述,以期为铝合金钻削加工出口毛刺的研究提供帮助。      

A New Burr Formation Model for Orthogonal Cutting of Ductile Materials

This paper proposes a new model to predict the full formation of a burr in orthogonal cutting. The model is based on the theory of slip-lines, the equilibrium equation, and experimental observations of burr formation with relevant data gathered from previous studies. Unlike with existing models, the proposed model considers the influence of the deformation rate on burr formation as well as the compression factor of the exit surface during burr development. A Mathcad program was created based on the model. The program can visualize burr formation and can predict the geometrical characteristics of the burr. The results of visualization are presented in the paper. The influence of the tool rake angle, the workpiece angle and the undeformed chip thickness, on burr dimensions have been verified in experiments. The experimental results show that the model is suitable in the cutting of ductile materials.     

The effect of using a sprung stripper in sheet metal cutting

Sheet metal cutting with punch and die is one of most fundamental processes in sheet metal presswork, and in many modern tools such as progression tooling a sprung stripper is used to help the punch withdraw from the strip after separation. The vast quantity of practical information which is available about the cutting process does not document whether the use of a spring stripper affects the cutting process. In this work, a tool with a sprung stripper was modified so that the sprung stripper was held back from the strip. Burr height readings were taken before and after the modification, as were electron micrographs of the cut edge. These were compared to determine the effect, if any, that a sprung stripper would have on the proportions of shear and tensile fracture and the burr height formed. When a sprung stripper was used, maximum burr was half as high as without. Process consistency was over twice as good with a sprung stripper. When a sprung stripper was used, burr was found to protrude into the hole, which did not happen otherwise. With a sprung stripper, there were more patches of secondary shear fracture than with no stripper contact. It is suggested that the use of a sprung stripper altered the path of tensile fracture and the amount of drawing in of the strip during cutting, thus altering the burr height and width.     

Optimization and control of drilling burr formation of AISI 304L and AISI 4118 based on drilling burr control charts

Control charts for drilling burr formation for stainless, AISI 304L, and low alloy steel, AISI 4118, were developed. Split point twist drills are used for the experiments of this work. A Drilling Burr Control Chart, based on experimental data, is a tool for prediction and control of drilling burrs. Burr classification was carried out based on the geometric characteristics, burr formation mechanisms and sizes of the burrs. New parameters consisting of cutting condition variables and drill diameter were developed, and used to show unique distributions of the burr types. Burr types and the resultant burr size showed great dependence on the new parameters regardless of the drill diameters. Through the chart, burr type can be predicted with given cutting conditions. Also cutting conditions that are believed to create preferred burr types can be selected.