共查询到18条相似文献,搜索用时 93 毫秒
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锡膏印刷机并联平台定位算法的研究 总被引:5,自引:1,他引:4
锡膏印刷作为表面贴装技术(Surface Mount Technology,SMT)工艺流程的第一道工序,也是SMT质量的基础.针对平台纠偏定位精度不高而导致印刷后PCB锡膏偏移的问题,从全自动锡膏印刷机并联平台的结构分析出发,根据其运动特性,建立平台的运动分析模型,结合最小二乘法原理,给出了一种定位速度快、精度高的定位算法.实验与应用中,通过机器视觉系统获取PCB与钢网上Mark坐标差值,经该算法定位后结合误差理论分析定位误差.结果表明,该算法可一次性完成纠偏·不仅节:节省了平台机械定位时间,而且有效避免了并联平台分步运动时的耦合误差,平台重复定位精度稳定在±10μm、±0.005°以内. 相似文献
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根据锡膏搅拌机的功能要求,分析了3种机械传动方案,比较后确定了结构相对简单的传统方案,并给出了基于MCS-51单片机的控制系统电路原理图. 相似文献
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柔性版印刷机机构复杂、装配精度要求极高,无论是机架和辊筒的安装都将对其质量控制产生重要影响。本文针对单个机架的安装和多组机架水平安装等情况下的几种不同的同轴度误差以及影响进行了定性分析;并对柔性版印刷机辊筒类组件的装配误差提出了改善性措施。从而为提高柔性版印刷机整体安装质量和印刷精度提供重要参考。 相似文献
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A location system is very important for solder paste printing in the process of surface mount technology (SMT). Using machine
vision technology to complete the location mission is new and very efficient. This paper presents an integrated visual location
system for solder paste printing based on machine vision. The working principle of solder paste printing is introduced and
then the design and implementation of the visual location system are described. In the system, two key techniques are completed
by secondary development based on VisionPro. One is accurate image location solved by the pattern-based location algorithms
of PatMax. The other one is camera calibration that is achieved by image warping technology through the checkerboard plate.
Moreover, the system can provide good performances such as high image locating accuracy with 1/40 sub-pixels, high anti-jamming,
and high-speed location of objects whose appearance is rotated, scaled, and/or stretched. 相似文献
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针对中小口径超声波流量计的弯管二次流误差问题,运用数值仿真技术,分析了弯管二次流垂直误差与水平误差,由二次流流线规律推导出了二次流误差的计算公式。结合实际的流量计测量范围,设定雷诺数的变化范围为3 000~50 000,定量分析了安装在弯管下游5D、10D、20D位置的流量计在不同雷诺数下的误差规律。提出了"用压力差来表现二次流强度,最终结合误差规律通过测量压力差来对弯管二次流误差进行修正"的方法。研究结果表明,在雷诺数29 000之后,10D处的二次流垂直误差超过了5D处的误差,二次流垂直误差和水平误差的最大值分别约为1.2%和0.7%,经过仿真验证结果表明,该修正方法可行。 相似文献
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旋转风速仪测量误差会导致风电场发电机组发电量损失、电能质量下降。通过测量实验对比三杯式风速仪和超声波风速仪,得出误差产生的主要因素是3.5 m/s以上三杯式风速仪的"过高效应"。该文提出一种风速测量校正方法,基于最小二乘法对三杯式风速仪的测风误差进行校正,能有效减小风电场测风系统测量误差。 相似文献
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Chung-Hsien Kuo Fang-Chung Yang Jein-Jong Wing Ching-Kun Yang 《The International Journal of Advanced Manufacturing Technology》2006,31(5-6):509-519
This paper aims to develop the 3D surface construction applications for the solder pastes using multi-projection images and the neural network approach. The proposed solution uses the image features of multi-projection angles as the inputs and the laser surface scanning results as the outputs of the neural network model to perform precise 3D solder paste surface construction. In this manner, the proposed methodology can measure the 3D solder paste surfaces in a precise way like the laser scanning results. The advantages of this work is to use a low cost and high speed image solution to overcome the disadvantages of high cost and slow speed laser solution while the inspection accuracy is maintained. The multi-projection images are captured from the multi-channel light source and the coaxial light source to perform precise and efficient inspections, respectively. On the other hand, the back-propagation (BP) neural network approach is used to construct the 3D solder paste surface models for various solder pad geometries. Finally, the proposed system was experimentally verified. The experimental results showed that the multi-channel light source solution with pad based learning achieves 95% volumetric accuracy in average, and the coaxial light source with sub-area based learning just achieves 80% volumetric accuracy in average when compared to the actual laser surface scanning. 相似文献
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流量测量是影响水轮机效率测试精度最主要的因素。大管径流量测量的方法主要采用超声波法,然而,其测量精度及误差构成尚无有效的校验方法。结合时差法超声波流量计的测流原理,推导得到流量综合误差,建立测流误差描述模型。提出一种基于流量测量理想系统来进行误差分析的量化方法,为超声波测流系统的误差分析与控制提供一种新的途径。通过测流理想系统对超声波测流精度的影响因素进行仿真研究,分析了各项参数测量误差对系统综合误差的影响,针对影响较大的主导因素提出了相关修正方法,并对系统综合误差的控制进行了分析。最后搭建实验系统进行研究,实验结果初步验证了该方法的有效性。 相似文献
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