HS-200BZ型实验室杯型砂轮自动磨样机的故障维修

一台HS-200BZ型实验室杯型砂轮自动磨样机砂轮转动正常,磨样机构水平移动也正常,但砂轮磨头始终不能上下移动。检查上下进给机械部分正常无卡阻,但是通电后步进电机始终不工作。在检查电控部分时发现,步进电机驱动器(MS-2HO-90M)无55V交流供电电源,但供电变压器本身输出55V电压正常,最后确认是保护部分UF11熔断器发生断路。在更换之后试运行,磨样机恢复正常。     

基于单片机开发的步进电机控制器在导轨磨床V型砂轮修整器上的应用

文章以导轨磨床V型砂轮修整器上的应用为蓝本,重点阐述了基于单片机开发的步进电机控制器的应用。     

陶瓷磨具生产工人基础知识问答(连载)

(278)那些规格砂轮需要进行回转强度检查? 除筒形、筒形带槽、磨针、磨砖、切矿石、磨钢球、磨米、孔槽螺丝紧固砂轮、无心磨导轮外,凡外径D≥150毫米的砂轮均应进行回转强度检查。然而外径小于150毫米的高速砂轮(V砂≥50米/秒)也一律要进行回转强度检查。     

防止DK3220B型线切割机步进电机松动的方法

我们厂的两台DK3220B型线切割机,在正常运行时步进电机有时自行松动,其中一台(TP801单板机控制的)这种现象比较严重。我们主要采取了下述二项抗干扰措施: 一、在给控制机供电的电子交流220V稳压器的输出端加接滤波器,目的克服稳压     

数控线切割机维修几例

(1)某DK7725数控线切割机是采用单板机改造的,执行加工程序时出现正向误差;切割圆时,加工零件呈椭圆形。试机时发现,X轴步进电机在执行加工程序时出现步进不稳情况,用手稍微用力亦可使其停止转动(在正常情况下用手不能使其停止转动)。初步估计是驱动电路问题。由于Y轴步进电机工作正常,因此+24V电源正常;检查功放极,发现一铜箔烧断,可能存在短路现象。对X轴功放管检查没有发现击穿,后发现有一个二极管击穿。该二极管起步进封锁作用,该管击穿后,造成步进控制信号出现误差,从而使步进电机产生失步。用同型号二极管更换后,工作正常。(2)新购…     

新型两自由度定子永磁球形混合式步进电机结构及性能分析

多自由度电机有望广泛应用于机器人和机器手等多运动自由度系统中。当前虽然有多种样机原型，但大多数都在实验室研究测试阶段，且电机机械机构、控制系统复杂，生产制造难度高，体积较大的同时材料利用率低。为了推进电机产品化进程和实际应用，提出一种新型定子永磁球形两自由度混合式步进电机。详细介绍电机结构及运行原理；建立电机齿层归一化分析模型，对电机空载和负载性能进行归一化分析，所得结论对于该类电机分析具有通用性；最后，设计一台整体外径为50 mm的新型定子永磁球形两自由度混合式步进电机样机，通过有限元仿真、与同规格转子永磁型两自由度混合式步进电机性能比较，验证了该新型电机性能的优越性，以及齿层归一化分析方法的可行性。     

带材轧机的在线磨辊装置

日本三菱重工业公司研制出一种直接安装在热带轧机上的在线磨辊装置。这种磨辊装置为无动力型,砂轮的旋转轴与工作辊表面的正交线之间有很小的夹角。当砂轮压向轧辊表面并给其施加一定的力时,小角度傾角使砂轮随工作辊按一定方向旋转和移动,进行磨削。该装置结构紧凑、构造简单,并能直接安装在任何轧机上。     

步进电源滤波不良引起的失步分析

故障现象一台SCX型线切割机在使用数年后,发生无规律的失步,严重时,步进电机只能抖动,不能正常进给。经检查,运算和控制部分正常,步进电机和线路接线也无故障,只有步进电源波纹较大,疑为故障由滤波不良所致,更换滤波电容后,故障消除。因此,断定上述怀疑是正确的,但是,为什么电源滤波不良会引起失步呢?这种失步又与哪些因素有关呢?针对这个问题,本文作如下分析分析一假设电源无滤波时的情况分析。电源失去滤波后,不再是纯直流,对于桥式整流,电源输出是以π为周期,按正弦规律变化的脉动直流,其脉动幅值即整流前     

S725半自动丝锥磨床能不能改成静压磨头

S725半自动丝锥磨床,系采用多线砂轮磨削,我厂用来加工各种规格丝锥,丝锥磨前可不先挑扣,而直接磨出螺纹,机床能自动工作循环,一次粗磨,一次精磨,即可成活。因此生产效率高。机床床身为箱形结构,有较好的刚性。工作台和砂轮架是沿着滚动导轨移动的,在工作台上装有头架和尾架,工作台移动是由可换丝杠、丝母传动的(丝母固定在床身上),因而大大简化了机床工作台和工件传动装置的结构,缩短了传动链,并提高了机床的精度。砂轮架上装有砂轮主轴和砂轮电机,体壳上部装有多线砂     

DK7732电火花线切割机维修两例

1 维修实例一 (1)故障现象:机床无空走(偶然也能正常运行)。试机控制器空走正常,当打上进给键时,拖板不动作,控制器也停止运行。 (2)故障分析:从上述现象看,只有当变频信号消失时,控制器才会停止运算即无空走。而当打上进给后,只使步进电机预放电路开始工作。因变频和预放电路共用+12V电源,所以应重点检查预放电路和+12V电源本身。     

金刚石砂轮修整机脉冲电源的设计与应用

针对传统的电火花金刚石砂轮修整机脉冲电源人机交互方式陈旧、电源主振脉冲抗干扰能力弱、放电效率低及寄生电感严重等的缺点,设计一款电火花脉冲电源。采用三菱PLC作为系统主控制器,选用STC8A8K64S4A12单片机与EPM570T100C5N CPLD可编程逻辑器件作为脉冲主控芯片,并进行电火花脉冲电源的硬件与软件设计。同时制作金刚石砂轮修整机电源样机,以石墨轮为电极,金刚石砂轮为加工工件进行放电加工试验,检验设计的电源加工性能,并与传统电火花金刚石砂轮修整机进行工艺对比试验。结果表明：设计的脉冲电源控制方式简洁,参数设置方便,放电波形抗干扰能力强,不易失真,放电效率较高,加工的金刚石砂轮表面质量较高,成型面颗粒完整度高。     

磨削机械的创新设计

对非平面或非圆柱面的曲面工件进行磨削加工,须用柔性的磨削机械。设计两大类柔性磨削机械,分别是圆形柔性磨削机械和齿形柔性磨削机械。其磨削装置是内部充满水、外部粘贴有砂砾的密闭的橡胶砂轮。根据帕斯卡原理,密闭的充满水的橡胶砂轮任何部位的压强都相等。橡胶砂轮与工件接触处的形状可以随着工件表面的形状变化而变化,但是橡胶砂轮与工件接触的任何点的压强却是相等的,这样工件与橡胶砂轮接触的任何部位都会被磨削得一样光滑。     

Assessment of Grinding Fluid Effectiveness in Continuous-Dress Creep Feed Grinding

Creep feed grinding is a high-productivity abrasive removal process that is often limited by thermal damage and high wheel wear. A review of current industrial practices in the area of fluid supply optimisation in grinding shows that very little knowledge of the pressure, flowrate and method of application exists in industry. This paper presents an experimental procedure to evaluate fluid supply conditions in grinding on a continuous-dress creep feed grinder. Using tapered workpieces, the authors have evaluated the influence of wheel speed and material removal rate on grinding fluid effectiveness, based on the material removal rate at the position of the wheel along the ramp when burn starts to occur and the corresponding spindle power surge. Correlations are investigated between visible discoloration, metallurgical examinations and change in spindle power, in order to establish the onset of grinding burn. This procedure serves to determine the upper limit of material removal rate or - respectively - the lower limit of fluid flow rate for given grinding systems consisting of specified wheel type, material type, fluid type and fluid supply nozzle. The advantage of the presented method is its easy and time saving application in industry, but it is also of help to researchers who need to optimise fluid supply conditions prior to their grinding tests.     

硬脆材料表面加工V形槽结构的试验研究

金刚石砂轮成形磨削加工技术是硬脆材料表面微结构加工的一种有效方法。应用V形砂轮在硬质合金YT15和Al2O3陶瓷两种材料表面进行V形微结构的磨削试验,通过磨削试验研究V形微结构的成形磨削效果、磨削参数对V形槽的表面质量及磨削过程中的磨削力和比磨削能的影响。试验结果表明应用V形砂轮可以较好地实现硬脆材料表面V形槽结构的磨削,在可加工性好的材料上V形槽磨削所需的磨削力和比磨削能相对较大。磨削参数的变化影响V形槽表面质量及磨削过程中的磨削力和比磨削能,其中比磨削能可以反应磨削过程中的材料去除方式。YT15表面的试验结果表明V形砂轮的磨损对加工出的V形槽的轮廓结构有相当大的影响。     

大尺寸硅片自旋转磨削的试验研究

利用基于自旋转磨削原理的硅片超精密磨床,通过试验研究了砂轮粒度、砂轮转速、工件转速及砂轮进给速度等主要因素对材料去除率、砂轮主轴电机电流以及磨削后硅片表面粗糙度的影响关系。研究结果表明,增大砂轮轴向进给速度和减小工件转速,采用粗粒度砂轮有利于提高磨削硅片的材料去除率,砂轮轴向进给速度对材料去除率的影响最为显著;适当增大砂轮转速,减小砂轮轴向进给速度,采用细粒度砂轮可以减小磨削表面粗糙度;在其它条件一定的情况下,砂轮速度超过一定值会导致材料去除率减小,主轴电机电流急剧增大,表面粗糙度变差;采用比#2000粒度更细的砂轮磨削时,材料去除率减小,硅片表面粗糙度没有明显改善。     

砂轮刚性对磨削性能及产品加工质量的影响

通过测量不同砂轮磨削时机床功率、磨削区温度、刀具的表面粗糙度和刃口质量,分析砂轮刚性改变对砂轮磨削性能和刀具质量的影响。研究发现:在一定范围内降低砂轮的刚性可以提高砂轮的磨削性能,改善刀具的加工质量。其中,加入体积分数10%的尼龙制备的砂轮对其刚性改善比较明显,在相同的磨削条件下,其磨削区的平均温度较普通砂轮磨削区的平均温度低50℃左右;累计磨削相同工件后,机床负载约为使用普通砂轮时的30%~50%;磨削得到的刀具表面粗糙度降低,可以达到R_a0.02μm以下,且磨削纹路规则;在×500倍显微镜下,观察不到刀具崩刃等缺陷,刃口质量得到明显改善。      

高速超高速磨削工艺及其实现技术

高速超高速磨削加工是先进制造方法的重要组成部分，集粗精加工与一身，达到可与车、铣和刨削等切削加工方法相媲美的金属磨除率，而且能实现对难磨材料的高性能加工。本文主要论述了高速超高速磨削工艺技术的特点；分析了电主轴是高速超高速磨削主轴系统的理想结构，介绍了陶瓷滚动轴承、磁浮轴承、空气静压轴承和液体动静压轴承在主轴单元中的应用；超高速砂轮主要用电镀或涂层超硬磨料(CBN、金刚石)制成，介绍了超硬磨粒的特点和砂轮的修整，分析了在高速及超高速磨床上得到广泛应用的德国Hofinann公司生产的砂轮液体式自动平衡装置；介绍了高压喷射法，空气挡板辅助截断气流法，气体内冷却法，径向射流冲击强化换热法磨削液供给系统的特点；最后介绍了直线电机进给系统和声发射智能监测系统等实现高速超高速磨削的关键技术。     

The coolant penetration in grinding with segmented wheels—part 1: mechanism and comparison with conventional wheels

This paper aims to study the mechanism of coolant penetration into a wheel-work contact zone when a segmented or conventional wheel is used in surface grinding. Based on the principles of fluid motion and considerations of spin-off and splash, analytical models for both conventional and segmented wheels were developed for predicting the power of pumping coolant into the contact zone. It was revealed that the pumping power of a segmented wheel increases with the increment of wheel speed, but that of a conventional wheel decreases. It was shown that coolant minimisation in surface grinding is possible when using a segmented wheel, although its efficiency depends on the wheel speed and methods of coolant supply. The model predictions were in good agreement with experimental observations.     

The effect of machine stiffness on grinding of silicon nitride

This study investigates the effect of machine stiffness on normal forces, actual depth of cut, and workpiece strength in grinding of silicon nitride. To obtain a grinding system with an adjustable stiffness, a compliant workholder is added to a precision grinder. Single-pass and multi-pass grinding experiments are conducted to evaluate the effect of machine stiffness. Cup-type diamond wheels of two different bond types and three grit sizes are used in the grinding experiments. Static and dynamic simulation is carried out to correlate grinding forces and actual depth of cut with machine stiffness. Since the simulation uses a time-domain model, it can accommodate non-linearities caused by the effect of machine stiffness on grinding forces and actual wheel depth of cut, workpiece regeneration, wheel wear, as well as wheel bond type and grit size effects, etc. Particularly, the model allows simulating grinding instability and the interference phenomenon due to residual material removal in multi-pass grinding. The study concludes that both simulation and experimental results have a good agreement.     

Study on micro-topographical removals of diamond grain and metal bond in dry electro-contact discharge dressing of coarse diamond grinding wheel

A coarse diamond grinding wheel is able to perform smooth surface grinding with high and rigid grain protrusion, but it is very difficult to dress it. Hence, the dry electro-contact discharge (ECD) is proposed to dress #46 diamond grinding wheel for dry grinding of carbide alloy. The objective is to understand micro-topographical removals of diamond grain and metal bond for self-optimizing dressing. First, the pulse power and direct-current (DC) power were employed to perform dry ECD dressing in contrast to mechanical dressing; then the micro-topographies of diamond grains and metal bond were recognized and extracted from measured wheel surface, respectively; finally, the relationship between impulse discharge parameters and micro-topographical removals was investigated with regard to grain cutting parameters, dry grinding temperature and ground surface. It is shown that the dry ECD dressing along with spark discharge removal may enhance the dressing efficiency by about 10 times and dressing ratio by about 34 times against the mechanical dressing along with cutting removal. It averagely increases grain protrusion height by 12% and grain top angle by 23%, leading to a decrease 37% in grinding temperature and a decrease 46% in surface roughness. Compared with the DC-25V power along with arc discharges, the Pulse-25V power removes the metal bond at 0.241 mm³/min by utilizing discharge energy by 73% and diamond grain at 0.013 mm³/min through surface graphitization, respectively, leading to high and uniform grain protrusion. It is confirmed that the impulse discharge parameters are likely to control the microscopic grain protrusion topography for efficient dressing according to their relations to the micro-removal of metal bond.