电镀金刚石钻头钻削碳纤维复合材料研究

碳纤维复合材料钻孔加工时极易产生分层、毛刺、撕裂等缺陷,是典型的难加工材料。针对碳纤维复合材料特点,以电镀金刚石钻头为研究对象,从钻削轴向力、钻孔出口质量等方面分析电镀金刚石钻头钻孔特点,并与硬质合金麻花钻进行对比,得出结论：电镀金刚石钻头钻削碳纤维复合材料时钻削轴向力较小,钻削质量较好,更适合于碳纤维复合材料的加工;钻头转速提高有利于减小钻孔缺陷的产生,钻削轴向力随钻头转速的升高而降低,随钻头直径的增大而增大;最后,通过多元线形回归方法得出电镀金刚石钻头钻削力经验公式。     

开颅手术中面向低损伤制孔的钻头结构优化设计

为降低颅骨钻孔过程中的钻削温度与轴向力,通过有限元仿真软件ABAQUS建立颅骨钻削模型,探究麻花钻主要几何参数（顶角、螺旋角、腹板厚度与横刃斜角）对机械损伤与热损伤的影响规律。制备可减小机械损伤与热损伤的优化钻头,进行试验。结果表明：麻花钻最优几何参数为顶角96°、螺旋角38.802°、腹板厚度0.8 mm、横刃斜角131.018°;与优化前的钻头相比,优化后的钻头具有更低的轴向力与钻削温度。     

刀具涂层和几何参数对钻削SiC/SiC的影响

为了研究SiC/SiC复合材料的加工性和在钻削过程中的切削力、刀具磨损和孔质量,使用整体硬质合金钻头和金刚石涂层的硬质合金钻头对SiC/SiC复合材料进行钻削试验,并设计正交试验对刀具的几何角度参数和钻削过程中的的切削力的关系进行分析,加工后观察刀具磨损和孔出口质量。结果表明:在低转速低进给条件下,金刚石涂层的硬质合金钻头适合加工SiC/SiC复合材料。在加工参数不变的条件下,对切削力影响最大的角度因素为螺旋角,其次是顶角,后角影响最小,并根据正交试验的结果得出一组最优刀具角度参数:顶角118°,螺旋角20°,后角16°。刀具的主要磨损形式是涂层脱落,孔出口缺陷的主要形式是毛刺和纤维拔出。     

可一次加工出孔和衬套的无屑热熔钻削技术

在薄壁工件上钻孔算不上是一种很大的挑战，但此类加工可能需要采取某种工件支承措施，以抵消钻头开始钻人工件材料时所产生的压力。根据加工要求，被加工孔可能还需要进行去毛刺或倒角加工。     

不锈钢模具微小孔钻削加工参数优化

为满足不锈钢模具微小孔钻削稳定,高效,精密的加工要求.针对模具微小孔钻孔过程中出现的排屑困难、钻头易折断、微小孔精度低、毛刺多、钻孔效率低、钻孔数量不稳定等技术难点,制定合理的加工工艺.通过设计正交实验,在实际生产中采集不锈钢微小孔钻削加工参数,利用正交实验分析法获得最优的参数组合.使用优化后的钻削加工参数进行不锈钢的...     

厚料小孔冲孔模设计

通过分析某型号产品电镀挂架的材料及形状,介绍了其加工工艺性,从模具模架的选择、固定板的选用、冲孔凸模的结构设计与材料确定、卸料弹簧的布局等方面介绍了其冲孔模具设计,详细介绍了冲孔凸模的材料选择和结构设计。最终,解决了钻床手动钻孔效率低下、劳动强度高、钻头寿命低、孔口毛刺外翻等问题。     

骨钻孔钻削力与钻削温度的研究综述

骨钻孔手术是关键的外科手术之一,广泛应用于修整骨折及颅骨开孔等方面.在骨钻孔手术过程中,医疗钻头与骨组织相互作用,不可避免地产生钻削力和钻削温度,从而导致不同程度的骨损伤.基于当前研究现状,综述了实验法和仿真分析法2种骨钻孔研究方法;阐述了医疗钻头钻削温度的产生、测量及其影响因素;分析了钻头参数、钻头设计及超声辅助钻削...     

基于双钻头的孔群加工路径优化算法

引入双钻头对孔群同时加工是提高钻孔效率的有效途径。分析双钻头进行孔群加工的数学模型,通过修改用于单钻头孔群加工路径优化的遗传算法中染色体的表达方式和适应度函数的计算方法,得到基于双钻头的孔群加工路径优化算法。实验结果表明,与单钻头的最优加工路径相比,在不同钻孔速度下使用双钻头同时加工的新算法都能节省近一半的加工时间,有效提高了孔群加工的效率。     

一种新型的钻头刃磨机

本文介绍一种新研制的钻头刃磨机。该机是用圆锥磨法的原理研制而成的,它不仅体积小,重量轻,而且调整方便,可刃磨出加工需要的顶角和后角。它的投入使用,可提高钻头的刃磨质量,从而获得明显的经济效益。     

金刚石钻进高强度钢混凝土的试验研究

金刚石薄壁工程钻头在建筑安装施工中的应用越来越广泛。本文针对钻进高强度钢筋混凝土，采用手持式、台式两种类型的工程钻机，配上电沉积金刚石钻头，进行一系列实际钻孔试验。得出钻机功率消耗和钻进速率之间的关系，钻进建筑用主要规格系列钢筋所需时间，并进行了分析研究，最后提出有利于提高钻头使用性能和钻孔效益的结论。     

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。      

Taguchi optimization in drilling of AISI 316L stainless steel to minimize burr size using multi-performance objective based on membership function

Burr in drilling plays an important role on product quality and hence it is essential to minimize the burr size at the production stage. This paper presents the application of Taguchi optimization method for simultaneous minimization of burr height and burr thickness influenced by cutting conditions and drill geometry. The approach of Taguchi design for drilling optimization problem is based on multi-performance objective, which employs the membership functions. In the present work, optimal values of cutting speed, feed, point angle and lip clearance angle are determined for selected drill diameter values to minimize burr height and burr thickness during drilling of AISI 316L stainless steel workpieces. The effectiveness of the proposed approach is demonstrated through simulation results and experimental verifications.     

A simple analytical model for burr type prediction in drilling of ductile materials

This paper proposes a new analytical model to predict the type of burr at drilling exit. The model is based on the theory of slip-planes and is specially developed to predict burr type formation in drilling of ductile materials. First the analytical model is set up, based on mechanical and geometrical considerations. Then it has been validated through experimental drilling tests on aeronautical aluminum by predicting burr type and thickness. The experimental results show that the model is suitable in the drilling of ductile materials and its validity domain has been established.     

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.     

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.     

Development of Drill Geometry for Burr Minimization In Drilling

The researchers carried out drilling tests using drills of various shapes to determine burr minimization. The ultimate objective of this study was to develop a compatible drill shape to minimize burr formation. For the experiment general carbide drills, round drills, chamfer drills and step drills are designed and manufactured. Burrs are generated under various cutting conditions using four different materials. A laser sensor was used to measure the burr dimensions. As a result of the experiments, step drill with specific step angle and step size Is suggested for burr minimization.     

CFRP/Al叠层材料变进给钻削表面质量分析

为了降低碳纤维增强复合材料(CFRP)/铝合金(Al)叠层制孔产生的纤维撕裂和毛刺高度,提出了一种基于几何函数设定进给量的方法,即当刀具位于叠层材料钻入区、叠层区、钻出区时,主轴进给量按正弦曲线的变化规律进行设定.在相同的加工效率下,将该方法同定进给钻削进行实验对比,分析了变进给钻削对轴向力、复合材料撕裂损伤以及金属孔...     

Monitoring of drilling for burr detection using spindle torque

This work proposes and evaluates a monitoring method, based on internal signals from spindle torque, to detect non-desired burr formation during drilling operations. Five features of this signal showed to be related to burr height. The selected features were sensitive to the exit burr while comparatively insensitive to changes in process parameters. The experiments were performed in aeronautics aluminium, Al 7075-T6, under dry high speed conditions. A thresholding algorithm has been developed to distinguish if burr height is below or above a previously established onset. The predictability of the developed algorithm is above 92% for the tested range of process parameters. An appropriate implementation of this monitoring system can be used as an effective quality control of drilling operations.     

Investigations on reducing burr formation in drilling

This paper reports the experimental investigations on reducing burr formation while drilling through-holes in metals. Experiments have been planned based on response surface methodology (RSM) technique. Mathematical models correlating response parameters (burr sizes) to the process parameters, e.g. feed, hole size and workpiece hardness have been obtained. Optimal process conditions to minimize the sizes of burr at the entry and exit of holes have been identified. In addition an attachment has been designed and developed to provide continuous modification of feed during drilling. It is reported that the optimal process conditions and the use of attachment can cause significant reductions in the sizes of burr.     

Prediction of Parameters for the Burr Dimensions in Short-Hole Drilling

The following paper presents a method for the determination of the burr dimensions to be expected in short-hole drilling, simultaneously taking the parameters into consideration which influence the burr formation. These parameters are yield stress, forces and the geometry of the inserts. The method is based on empirical cutting examinations and takes account into the correlation between different burr parameters and the machining conditions such as cutting speed, feed and tool geometry. Using Schaefer's burr value g, it is possible to make a quantitative evaluation of the burr dimensions. The method was verified for the materials 16 MnCr 5 and Ck 45 in case of dry machining.