How can’t use existing tools machining special groove structure?

In parts of the car wheel groove structure, for example, through the cutting tool graphics CAD drawing forming, set up in the Mastercam software tool, and USES the virtual machining line instead of actual processing line of groove parts turning processing;Finally finished part for the cutting plane three-dimensional scanning, processing results conform to the requirements of the model was verified.
& have spentMastercam is modern processing technology is a kind of commonly used software, it can not only create different processing methods under the standard tools, also for customers with custom tool creation way, convenient for the user according to the special requirements of work piece to create the corresponding cutting tools.In this paper, according to the requirements of the groove structure characteristics, and processed, created the forming cutter, through virtual machining line edit program, processed and verified.
& have spent1. The cutter figure drawn
& have spentAs shown in figure 1, wait for processing structure by R0.5 mm, R14mm arc and straight line 1 mm wide, if you are using a standard cutting tool processing, can only choose on both ends of the blade with arc R0.5 mm, straight line length is 1 mm, 2 mm width of the blade as a whole is the standard blade, but the blade strength is not enough, easy to damage.Combined with groove structure (see figure 1), therefore, we design a forming cutting blades, the blade cutting edge upper part forming in the groove structure R0.5 mm and 1 mm straight, the lower part is R3mm arc;In the machining process, the first half of the blade to ensure that the groove R0.5 mm and 1 mm linear modelling, the second part of turning other parts, at the same time the total blade width is 4.5 mm, can increase the whole strength of the blade.Create tool section in the CAD graphics, as shown in figure 2, and saves the file as a DWG file format.
& have spentFigure 1 a groove structure
& have spentFigure 2 forming cutting tool & have spent2. Create a tool
& have spentMastercam users can customize the cutter, but required cutting tool pattern cutter bar and the blade in a 2 d figure are located in different layers, and the tool holder and the blade must be different colors.First open the saved with Mastercam good DWG format graphical tool, as shown in figure 3 R0.5 mm circular arc of the circle as the reference point tool moving to the origin, and then to save cutter graphics for MCX file format.
& have spentFigure 3 MCX format tool
& have spentChoose in lathe processing mode, the tool management & rarr;Right-click the new cutting tool, cutting tool type choose custom, under the graphics menu, save good MCX file to import, defined as grooving cutting tool form.Mastercam provides only the single arc radius and the arc center set up, aiming at forming cutting tool can’t identify the blade width, so the blade can only choose to R0.5 mm or R3mm single circular definition, this article R0.5 mm circular arc, for example to create and save to library of tools, cutting tools list as shown in figure 4.
& have spent

& have spent

& have spentFigure 4 generating tool list
&

have spent3. Make virtual machining line
& have spentDue to cutting tool defines the arc radius and center R 0.5 mm, so when programming need to develop the virtual machining line with single arc turning R0.5 mm instead of turning the actual processing line of forming tools.Single arc R0.5 mm and R3mm both 2.5 mm from actual machining center, so the actual R3mm arc machining parts of the processing line to offset the 2.5 mm, then upward along the Y-axis translation 1 mm (the actual blade between two circular arc in the Y direction is 1 mm spacing), along the X axis of 2.5 mm to the right translation, with the original R0.5 mm tangent arc machining parts again, connection formation in R0.5 mm arc processing of virtual machining line, as shown in figure 5 arrows of the dotted line.
& have spent4. Select machining path, the generated code
& have spentIn turning mode, virtual machining line of route choice as shown in figure 5, choose to create a good cutting knife, the machining process simulation is shown in figure 6, generation processing G code is as follows:
& have spentFigure 5 virtual machining line & have spentN316 G0 Z143.3895
& have spentN318 X459.4
& have spentN320 G3 X455.4 Z145.3895 I0. K2.
& have spentN322 G1 Z147.0803
& have spentN324 G3 X459.8 Z153.6803 I11. K0.
& have spentN326 X461.4 Z154.0803 i. 8 K – 6
& have spentN328 G1 Z153.0803
& have spentN330 G2 X463.4 Z152.0803 I1. K0.
& have spentN332 G1 X475.9858
& have spent5. Verify the processing effect of
& have spentTo make cutting plane processed grooves parts, and use the three-dimensional scan cutting cross section, and compared with the original molding line, as shown in figure 7.After comparison, the processing of profile modeling conform to the requirements of the original model.
& have spentFigure 6 processing
& have spentFigure 7 groove part contrast test & have spent doing the cutting plane6. Conclusion
& have spentWith the diversification of modern mechanical structure, the specific structure of the forming tool processing is important means to ensure that products comply with the design of the original.In the light of the special groove can’t use the existing tooling structure, forming cutting tools are designed, and according to its processing, finished the processing procedure of the editor, for the forming cutting tool in the application of modern processing technology provides a solution.
& have spentAuthor: citic wear card co., LTD. (066011) in hebei liu Seedlings in the month louie Li loose, reproduced please indicate
& have spent(the original title: can’t use special groove structure of existing tooling, how processing?)(source: metal processing)

Inventory of nc machine tool spindle common fault and the solution

Spindle is referring to the machine drives the workpiece or tool axis of rotation.Machine tool spindle are usually made of the main shaft, bearing and transmission parts (gear or pulley), etc.There are mainly two kinds of high-speed spindle in the actual application:
& have spentKind of transmission of high speed motorized spindle is zero, this kind of main shaft by using the structure of the motor and spindle integration, and through the accurate dynamic balancing correction, so have good rotation accuracy and stability, but the output torque and power limit.
& have spentAnother kind is variable frequency spindle motor and mechanical transmission mechanism with the combination of the spindle.This type of spindle of the output torque and power far more, but relatively rotation accuracy and stability to almost, so for this type of spindle, how to properly design influence on the machining accuracy of machine tool spindle and its components are critical.
& have spentNc machine tool spindle common fault and the solution
& have spentA, with variable frequency spindle turn
& have spentThe cause of the problem and the processing method:
& have spent(1) caused by the failures of mechanical transmission: look for fracture belt drive whether or machine hung up the gap.
& have spent(2) the supply of the main shaft of the three-phase power supply lacks or reverse phase: check the power supply, switching of the two power cords.
& have spent(3) circuit connection error: refer to the circuit connecting the handbook, to ensure the correct attachment.
& have spent(4) the system has no corresponding spindle control signal output: the multimeter measurement system output signal, without the spindle control signal output, is the need to change IC components or send the relevant plant maintenance.
& have spent(5) system have corresponding spindle control signal output, but the power supply circuit and the control signal output circuit break or damage of components: the multimeter to check system between the spindle motor and power supply circuit, signal control circuit whether there is open circuit;Whether there is open circuit;The connection between the contact is bad contact;There is no damage to ac contactor, dc relay;Check thermal relay over-current;Check whether insurance tube burning, etc.
& have spentSecond, the spindle with frequency converter not turn
& have spentThe cause of the problem and the processing method:
& have spent(1) caused by the failures of mechanical transmission: look for fracture belt drive whether or machine hung up the gap.
& have spent(2) the supply of the main shaft of the three-phase power supply lacks: check the power supply, switching of the two power cords.
& have spent(3) numerical control system of inverter control parameters not open: consult system specification, variable frequency parameters and change.
& have spent(4) system and the inverter circuit connection error: refer to the attachment instruction system and converter, and ensure the correct attachment.
& have spent5 analog voltage output is not normal: use a multimeter to check the system output analog voltage is normal;Check the analog voltage signal wire connection is correct or poor contact, inverter receive analog voltage matches.
& have spent6 high-voltage electrical control part of the circuit or component damage: check the spindle power supply this line contact connection is reliable, line ever open circuit, dc relay is damaged, if insurance tube burn out.
& have spentCruelly inverter parameters set: frequency converter contains control mode selection, divided into the inverter control panel spindle way, way of NC system to control the main shaft, etc., if you don’t choose the NC system control mode, the spindle can’t use the system control, change the parameters;Check the related parameters setting is reasonable.
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3, without frequency conversion of the spindle (shift the spindle rotation speed is not controlled
& have spentThe cause of the problem processing method:
& have spent(1) the control signal output system without S01 – S04: look for gear shift control signal output system.If no, then the system failure, replace the IC or send for repair.
& have spent(2) the connection line fault: if the system has the shift control signal output, then check the connection line whether there is open circuit or poor contact, check whether dc relay or contactor is damaged.
& have spent(3) the spindle motor damage or short circuit: check the spindle motor.
& have spent(4) not mechanical shift: hang up yourself.
& have spentFour, spindle brake
& have spentThe cause of the problem processing method:
& have spent(1) abnormal braking circuit or high voltage components damage: check the bridge pile, fuse, ac contactor is damaged;Check whether high voltage circuit breakers.
& have spent(2) the braking time is not long enough, or the inverter braking time parameter adjustment system.
& have spentNo braking signal output (3) system: replacement of internal components or sent for repair.
& have spent(4) inverter control parameters set: refer to instruction manual frequency converter, inverter parameter set correctly.
& have spentFive, the spindle start immediately after stop
& have spentThe cause of the problem processing method
& have spentEnough time: (1) the system output pulse adjusting system of M code output time.
& have spent(2) the inverter in the running state: refer to the instruction for use of frequency converter, set up parameters.
& have spent(3) main line of control components damage: check circuit all touch the contacts are in good condition, check whether the dc relay contactor is damaged, contact not self-locking
& have spent(4) the spindle motor short circuit, causing thermal relay protection: investigate the cause of short circuit, to reset the thermal relay.
& have spent(5) the spindle control circuit without self-locking circuit, and the parameter is set to the pulse signal output, make the spindle will not operate properly, the system control spindle to control parameters instead of level control.
& have spentSix, the spindle rotation can’t stop
& have spentThe cause of the problem processing method:
& have spent(1) ac contactor or dc relay is damaged, and off for a long time, can’t control: the change of ac contactor or dc relay.
& have spent(the original title: all kinds of machine tool spindle fault solution! Learn to earn!) (source: to check the net)

Based on state of the nc machine tool spindle reliability evaluation

The health status of nc machine tool spindle is directly related to the quality of the product and enterprise’s safety production.According to the condition monitoring data of nc machine tool spindle, built a hidden Makov model is based on observation sequence model for reliability evaluation.该模型提出了Spea「m an权重分析方法 ,通过对多性能指标观测序列及设备健康状态的Spearman秩相关分析获得各性能指标的定量权重 ,体现了各性能指标在设备健康评价中的贡献。并利用矢量量化及加权分析将多性能观测序列转换为单观测序列,通过隐M arkov模型获得设备状态变迁概率 ,从而实现对设备的可靠性评估。最后将上述模型应用于某型数控机床主轴的可靠性评估 ,模型评价结果与场数据比较吻合,证明了该模型的有效性 。
   关键字:数控机床;主轴;隐Markov模型;可靠性评估;Spearman权重
   0.引言
   数控机床是加工零件的机器 ,广泛运用于国家重点企业。为了保证数控机床的安全运行,必须对其进行可靠性评估。可靠性评估的方法比较多,从设备故障角度出发 ,Keller等m和 Das K等 H分 别通过分析数控系统和机械设备故障维修数据建立可靠性评估模型。针对统计数据模型样本小和不准确问题 ,有学者引人贝叶斯理论 ,综合验前信息和样本信息 ,能减小样本容量和提高准确性,Jason R.W等P1应用贝叶斯理论方法对数控机床进行可靠性评估。但该方法没有考虑设备缓慢劣化的过程,不能揭示设备失效本质。因此 ,Lu等立线性退化数据的模型和分析了HCI退化形式 ;吴军基于性能参数评估了数控装备在一个加工周期内的服役可靠性。为分析出设备故 障的原因、模式 、机理 、部位和频率等方面 , 通过建立设备的故障树和故障模式影响分析表 ,Pickarc F和张国军等分别建立M -FM EA模型和提出基于二元决策图故障树可靠性方法,得到故障树的不可靠度表达式。但完整故障树和故障模式影响分析表要求对设备基本组成和运行原理是否熟悉,对分析人员的现 场经验要求很高 。
   以上方法的评估结果主要基于批量产品整体的可靠性水平 ,但不能体现由于操作、加工、维护、环境等不同而造成的个体实际差异。因此,欧健51和118118丨-111;11等从设备状态角度分析,分别建立Markov过程的柴油机监控系统可靠性评估方法和应用 Markov模拟刀具磨损过程。但是马尔科夫分析存在状态真实值与状态观测值不一致问题,而隐Markov模型能够很好地对状态间的跳转进行描述 ,将外在表现的特征和内在蕴含的状态联起来,O cak、Purushotham[11_1l 和罗锡梁[13^ 隐 Markov 模型fe用到轴承和大型变压器的故障诊断 ;张春良M和熊尧、吴军等P句提出基于隐Markov模型的设备性能退化建模与分析的评估方法;Camci M和邓超、孙耀宗等#_211分别利用基于多性能参数 、多观测序列隐Markov模型评估了数控机床 钻头和Z 轴滚珠丝杠的健康状态。然而对于描述设备健康状态的多观测序列,由于不 同指标对设备劣化程度的表达通常是不一致的,因此在 利用多性能指标进行健康综合评价时应给予不同的重视程度,但在上述研究中都忽略了该 问 题,从而影响了评估结果的准确性。因此,本文通过对多性能指标观测序列及设备健康状态的Spearman秩相关分析获得各性能指标的定量权重,从而体现了不同性能指标在设备健康评价中的重要度。并利用矢量加权将多性能观测序列转换为单观测序列,应用于基于隐Markov模型的数控机床主轴可靠性评估 。
   1.基于状态的可靠性评估模型
   1.1 隐Markov模型
   隐马尔科夫模型(H idden Markov M odel,HM M )是一种统 模型是由两个相互关联的随机过程构成的一种双重随机模型;有限个状态转移的隐式随机过程( Markov链 )、与 M ark o v^中每个状态相关的观测序列的显式随机过程,其中,观测序列的结果可测可见, 而状态转移不可测不可见,只能通过观测序列的结果来体现,观测序列与状态之间通过概率分布相关联。标准隐Markov模型通常可由一个五元组表示:
 
  在机床的运行过程中,为了保证设备或部件的安全运行 ,现场工作人员需要对机床健康状态进行评估。然而机床的健康状态并不是一个直观可见可测的指标,通常是通过对多个性能指标的劣化程度来综合描述机床的健康程度。比如机床的工装夹具,夹紧气检压力 、松开气检压力和定位面气检压力这3个指标可共同反映工装夹具的工作状态,当这3个指标中的任何一个出现异常时,都意味着工装夹具的性能出现劣化趋势。因此,我们可以将数控机床的健康状态和性能指标分别看做HMM模型中的隐状态和可观测值,健康状态和性能指标的映射关系可看做观察值概率矩阵 ,从而可以通过HMM模型实现对数控机床的可靠性评估。
   1.2 矢量量化
   由于机床的健康状态不是一个可测的指标,通常可 以根据经验采用一个离散的变量序列来映射其不同的劣化程度。通常,健康状态等级可定义为:
 
  量化指标 。为便于HMM模型中的计算分析 ,需要将性 能指标进行矢量量化处理成为离散型的状态变量。根据数控机床的运行规则要求或现场经验 ,每项性能指标都设置了一个阈值范围 ,当性能指标处于阈值范围之内,表示设备状态可接受 ,反之 ,则认为设备存在隐患甚至面临失效的风险。性能指标等级一般可定义为:当指数呈单调变化时:
    1.3基于Spearm an的性能指标权重计算
   通常机床的健康状态由多个性能指标来综合描述 , 然而在实际运行中每个性能指标与设备或部件的整体健 康状态的相关性一般不同,即权重不同。对于权重大的性能指标 ,其劣化往往标志着整体设备或部件的劣化 ,而对于权重较小的性能指标 ,其劣化对机床整体或部件造成 的健康影响有限。因此 ,准确获取性能指标的权重对于科 学评价机床或部件的健康状态具有重要意义。 由于机床 的健康状态是通过各性能指标的具体表现来体现,二者之间存在一定的映射关系,因此可将性能指标的权重分 析转换为性能指标与健康等级序列之间的相关度分析。
    1.4多观测序列的转换
   在典型的HMM模型中观测序列是一个单行能指标序列,而数控机床的观测序列通常是多性能指标序列,且每个性能指标不同的劣化程度导致不同的整体健康状态,因此,多性能指标观测序列不能直接应用于HMM模型。本文将利用权重将数控机床的多性能指标观测序列量化转换为单性能指标序列。在上文中已经通过Spearman秩相关性算法获 得了各性能指标的权重 ,因此 , 在综合考虑各性能指标对总体健康状态影响的基础上,可以得到不同时刻的加权可观测值序列:
    2.基于多指标加权隐M arkov模型的数控机床主轴可靠性评估分析
   某型号汽油发动机缸体缸盖生产线上的数控机床(CBM 2180B)主轴结构如图2所示,该机床主轴主要用于镗曲轴孔和铰销孔。根据机床运行手册、现场调研及故障树分析,建立主轴的性能指标向量:近端端面跳动 、远端端面跳动和拉刀力。图2中,刀具夹紧装置处的力为拉刀力,采用拉刀测力计测量 ,主轴上面夹紧刀具加工工件一侧的跳动为远端端面跳动,另外一侧的跳动为近端端面跳动,分别用百分表打检棒在远端和近端测跳动。由于机床主轴的性能劣化速度较慢寿命一般可以达到3a,因此,主轴主要采取离线点检方式进行日常监测,正常点检间隔为3^月,强化点检间隔为1个月。
 
  表1为自2013 年5月到2015年9月CBM2180BITL床主轴的点检数据。根据机床运行手册 ,主轴近端端面跳动、远端端面跳动和拉刀力的阈值范围分别为 :[0,0.005]、[0,0.030]和 [31,5 9 ]。因此 ,本文根据阈值范围将各性能指标划分为3个状态区间 ,如表2所 示 。根据经验 ,可建立主轴各个性能指标观测序列与健康状态等级的映射规则,如表3所示 。其中 ,健康等级中的1、2 、3 、4分别对应优良 、一般 、劣化、故障4个等级。根据式(1 1 )和式 (1 2 )分别计算出相关系数 、权重如表4所示 。根据表3划分的状态区间及矢量量化规则 ,通过对性能指标的观测序列进行加权矢量分析后得到的观测序列 及其等级划分如表5和表6所示 。
   表1 主轴检测参数记录表 
表2 性能指标状态分类
   根据计算结果和经验判断划分观测状态等级如表6所示 。因此 ,利用矢量量化模型计算转化成加权可观测序 列 为 :0 * = [1 1 1 1 1 1 1 2 2 1 2 2 2 3 24 4 4 4 4 4 4 4 4 1 4 5 5 5]〇 设初始模型参数为ff0={l,〇,0,〇M〇和 如 下 :
 表3 主轴各性能指标及健康状态等级映射规则
 
表4 各个性能指标相关系数和权重
   迁曲线图及主轴可靠度变化曲线分布如图3、图4。通过图3中的主轴状态概率变迁可以直观地看出机床主轴在不同时期健康状态的变化趋势。在初始阶段 ,机床主轴处于“优良 ”状态的概率为1随着时间的推移,机床主轴逐渐开始劣化 , 其处于“优良 ”状态的概率不断下降 ,而 “一般”、“劣化 ”、“故障 ”的概率不断增加。在前7个月 ,主轴处于 “优良 ”状态的概 率 最大 ,从第7个月到第3个月 ,主轴处于“一 般 ”的概率最大,第13个月到第18个月 ,主轴出现“劣化 ”状态的概率最大,从18个月以后,主轴出现“故障 ”的概率最大。但是由于我们将主轴状态分为了4个等级,根据式( 14 ),尽管从第 18个月开始主轴出现 “故障 ”的概率最大,但是并不意味着此时主轴开始失效。根据最大隶属度原则故障 ”的概率大于其他3个状态的概率之和时 ,才认为主轴失效 ,在图4 中这个时刻对应的是第23个月。而根据表6 的矢量量化转化成观测序表及表5主轴各性能指标及健康状态等级映射规则,可知主轴在第27个月开始进入故障状态 ,该判断结果与HMM模型计算结果基本吻合,且HMM模型计算结果趋于保守,由此验证了本模型的正确性。
   表5 矢量量化转化成观测序列表 

表6 观测状态等级表
    3.结语

 
 
  针对目前可靠性评估中未考虑性能指标之间重要度问题,本文提出了一种基于多序列加权隐Markov模型的可靠性评估模型。首先确定多个性能指标向量,划分指标的状态区间进行矢量量化,其次建立了各性能指标及健康状态等级映射规则,引人Spearman秩 相关分析法 ,计算出不同性能指标之间的重要度 ,通过矩阵转化和矢量量化得到了加权可观测序列 ,然后将该序列代人隐Markov 模型训练获得稳定模型 ,并进行状态可靠性评估获得状态概率曲线和可靠度曲线。将本文的模型结合某型机床主轴2013年5月到2015年9月现场实际数据,状态概率变迁图分析,根据最大隶属度原则,得到主轴的各种不同状态会相继出现,可靠度变化图表明,主轴会在第23个月发生故障,通过实际主轴点检数据得到主轴在第27个月开始进人故障状态,结果比较吻合并且趋于保守〇本文的研究表明 ,基于多序列加权隐Markov模型是可靠性评估的一条新途径,研究结果可以为数控机床主轴可靠性的提高提供参考。
   (原标题:基于状态的数控机床主轴可靠性评估) (来源:华中科技大学)

The broaching machine industry transformation in the development of our country should be firmly grasp the development and technology

作为一种高效率、适宜大批量零件加工的金属切削加工设备,拉床主要应用于汽车、摩托车、农机、航空及工程机械等行业。虽然在金属切削机床中其比例目前仅为0.8%~1%,但由于其加工尺寸和形状位置精度高、操作维修方便、加工成本低且易实现自动化,拉床的应用范围日益广泛,其工艺范围也由一般的内孔和平面拉削扩展到较复杂的型面加工。  一、拉削技术需加快发展进度  据了解,拉削一道工序就完全可以取代传统的铣、磨、刨三道工序,但是由于国内拉削技术发展缓慢,也没能得到较好推广,拉削机床在金切机床中一直处于非主流地位。因此,我国拉床行业进一步发展需要紧牢抓研发和技术。立式上拉式内拉床  这些差距具体表现在,首先是产品设计手段落后,产品技术储备差。我国拉床设计基本上仍采用传统的手工经验计算和类比法,速度慢且易出差错,影响了新产品开发进度和产品质量,而一些厂家又满足于现有市场,缺少使用一代、研制一代、开发一代的长远战略目标,自行开发能力差。  其次,拉床的整体结构、辅助装置、通用配套件等仍停留在普通的设计制造加工水平上,缺乏独立先进的科学设计、制造、售后技术服务能力。而受国内数控、电气、液压、气动、冷却等配套元器件的制约,拉床的功能复合化和自动化水平也比较低。  此外,部分产品结构设计不合理,材料及热处理使用不当,检测手段不完善等,也直接影响着拉床本身的几何精度及加工精度。  二、研发步伐须加快  有业内人士表示,相比已跻身于国际前沿的机床行业,特别是钻镗类加工中心,我国的拉床制造仍处于世界二、三流水平。随着汽车等制造行业的竞争日益激烈,其对拉床的精度、效率、柔性、可靠性、通用性、环保性等的要求也越来越高。  显然,国内企业的脚步也在加快,在保证配套零件的精度及表面粗糙度的基础上,不断提高工效。  (原标题:我国拉床行业进一步发展需牢抓研发和技术) (来源:长沙思胜智能设备有限公司)