大尺寸工件的测量方法

大尺寸工件的测量方法徐州市计量测试技术研究所冯陆君随着我国机械加工工业的发展，大型机械零件的加工精度不断提高，因此对大尺寸工件的测量要求也愈来愈高。大尺寸一般是指５００ｍｍ以上尺寸，在重型机床、工程机械、矿山机械和建筑机械的产品零件中占较大的比重。这...     

大尺寸量规公差问题

尺寸大于500毫米的工件,多半是用带有指示表的量规来检查。这种带指示表的量规能保证测量力不变。用一般结构的量规检查工件时,除了有温度的影响外,还有由于卡规和内径规的弹性变形而产生相当大的测量误差。在大量生产中一般采用无读数装置的刚性极限量规,而在小量及单件生产中,则采用带有读数装置的可调整的量规。如果在规定的检查制度里,尺寸大于500到5000毫米的工件必须用量规来检查时,对于5级精度以下的外尺寸,推荐采用刚性卡规和可调整卡规,而4级以下的内尺寸,则采用内径量     

短锥量规的测量

本文介绍圆锥量规中的一种较为特殊的1：4短锥量规的测量方法。主要从大量规的锥度及大端尺寸的测量两方面进行探讨。     

CAPP系统中的工序尺寸和公差的计算

CAPP系统的理想输出应包括加工尺寸的刀具移动轨迹,而不是只输出与数控机床坐标系统无关的尺寸和公差,否则会增加NC程序的额外工作。该论文论述了CAPP系统中的工序尺寸链分析计算的新方法(ODTC)。它是在以往的研究工作的基础上提出来的,主要用于数控机床加工生成工序尺寸链。是CAPP系统内容的一部分。     

大孔径工件内径的测量

本文重点介绍采用长杆量规对大孔径工件内径测量的原理、方法、测量实验及误差分析。     

综合量规公差的选取与公差带位置的确定原则探讨

目前,我国尚未制订综合量规的国家标准。本文利用概率与数理统计方法,分析一定工艺条件下的量规公差及其位置与工件的误收、误废概率的关系,并在此基础上,阐述综合量规的公差选取与公差带位置的确定原则。     

大尺寸工件外圆圆柱度测量方法的探讨

根据高精度大尺寸外圆圆柱度的测量要求,在现有长度测量仪器基础上,改装其测量装置,配备具有径向测头的电感测微仪,用三等量块中心长度实际值与工件外径尺寸进行比较测量,作为评定大尺寸工件外圆圆柱度及外径尺寸的一种测量方法.测量要求圆柱度为0.001mm,测量结果为0.00093mm,满足了测量要求.     

关于垂直相交孔中心距检测量规的设计

本文介绍了利用尺寸链换算的方法确定垂直相交孔中心距的检测量规的设计方法及应用实例。     

现行螺纹量规公差存在的问题与解决办法

本文简介了GB／T3934-2003(审查稿)与ISO 1502及GB／T3934-1983之间的差别，文献都指出螺纹量规公差存在问题，作者更进一步指出螺纹环规要求的是单一中径，而用校对螺纹塞规检验的是作用中径，只有分项检测才能满足单一中径的要求。又指出分项检测不能测量小尺寸螺纹环规，仍需用校对螺纹塞规检验，而现行的校对螺纹塞规的公差过大，Tep远大于TR／3。最后作者又给出解决问题的意见。     

压力表自动检定仪的设计

利用单片机、步进电机驱动器、步进电机为主要硬件,构建压力表自动检定装置。根据检定规程要求,由单片机控制造压系统,由键盘设置压力点,实现检定过程自动化。装置自动采集标准压力值,自动计算示值误差、回程变差、轻敲位移。保存检定数据、打印检定结果。     

采用光纤传感器的电子塞规的设计

针对内孔零件批量快捷测量的问题，提出了基于反射式光强调制型光纤位移传感器的电子塞规测试系统。介绍了系统的测量原理与机械结构，设计了光纤位移传感器的结构和补偿算法。     

Some aspects of clip gauge design

Measurements show that simple beam theory accurately models the performance of clip gauge transducers. Assuming typical dimensions for the single and twin cantilever gauge it is found that the single cantilever gauge possesses about four times the sensitivity of the twin cantilever gauge, for the same stiffness. Design rules are specified by which gauges of high sensitivity and low stiffness may be constructed. A simple and reliable technique for fastening clip gauges to a test piece is introduced.     

Verification of the duplex gauge using variable strains and temperatures

Four steel specimens were equipped with "duplex nances", a recently proposed transducer based on two different electrical resistance strain gauges, capable of correcting the effects induced by temperature. The examined innovative transducer, in comparison with traditional strain measuring systems, has the advantage of utilising two strain gauge channels of the same type, which significantly simplifies automatic measuring systems. The specimens were subjected to temperature and strain field variations in the ranges of=30–150°Cand=100–700μm/m respectively The temperature and strain values obtained from the duplex gauges were compared with those measured by means of traditional methodology, i.e. a strain gauge and a thermocouple.     

低温绝热容器中皮拉尼真空计取代热偶真空计的可行性分析

在低温绝热容器夹层真空度的测量中,皮拉尼真空计和热偶真空计较适用,目前热偶真空计应用较多。从测量范围、测量精度、测量温度、互换性、远程监控、检漏能力和性价比等方面,对皮拉尼真空计和热偶真空计的性能进行了比较,得出皮拉尼真空计更适用于低温绝热容器夹层真空度测量的结论。最后列举了目前国外几种典型的商用皮拉尼真空计和热偶真空计的技术参数。     

反渗透技术在钢厂特大型废水回用项目中的应用

针对山西某大型钢厂不锈钢股份有限公司工业废水成份非常复杂、含盐量高和处理难度大等特点,以及国家对钢铁企业节能减排的号召,确定了以反渗透技术为主的脱盐工艺来回用该厂的工业废水,有效降低该厂吨钢的新水消耗量.运行结果表明,反渗透系统的脱盐效果非常好,给钢厂带来了很好的水质保障.本文详述了时代沃顿反渗透膜在钢铁厂废水回用系统中的应用情况.     

A design for an immersable pressure-capacitance gauge

An immersable pressure-capacitance gauge has been designed which has a linearity over a pressure range, is non-magnetic and has twice the sensitivity of a single diaphragm     

Ultrasensitive strain gauge with tunable temperature coefficient of resistivity

We demonstrate an ultrasensitive strain gauge based on a discontinuous metal film with a record detection limit as low as 8.3 × 10^–6. Constructed by well-tunable crevices on the nanometer scale within the film, this gauge exhibits an ultrafast dynamic response to vibrations with a frequency range of 1 Hz to 10 kHz. More importantly, the temperature coefficient of resistivity (TCR) of the metal film is tunable owing to the cancellation effect caused by the possibility of tunneling across the nanoscale crevices (showing a negative temperature dependence) and the electron conduction within the metal islands (showing a positive temperature dependence). Consequently, a nullified TCR is achievable when the crevice size can be precisely controlled. Thus, a fabrication strategy to precisely control the nanoscale crevices was developed in this study through the real-time tracking of the electrical conductivity during thermal evaporation. The ultrasensitive strain gauge with a tunable thermal drift introduces numerous opportunities for precision devices and wearable electronics with superior reliability.

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DL-6A型电阻真空计的误差

本文介绍DL-6A型电阻真空计的误差。DL-6A型电阻真空计测量范围是10-1~105 Pa,在10~5×103 Pa,误差为10%,在小于10 Pa和大于5×103 Pa误差为35%。