基于高速摄像技术及图像识别与处理技术,采集木质复合材料铣削过程中切屑流的瞬态图像,并对瞬态图像进行预处理;利用ProAnalyst运动分析软件,分析切屑流形成机制、流场速度及扩散角度的变化规律。结果表明:切屑流形成过程分成两个阶段,第1个阶段为切削层材料离开工件形成切屑开始到与齿槽接触;第2个阶段为切屑离开齿槽之后向外飞射,最后扩散在大气中。切屑流流场速度变化也分为两个阶段,第1个阶段为切屑流从形成时,具备一定流场速度后,开始趋于减小;第2个阶段为切屑流流场速度突然达到峰值,然后速度随之趋于减小。木质复合材料高速铣削时,随着刀齿切入工件,铣刀转速会趋于降低;而随着刀齿离开工件瞬间,刀齿线速度迅速恢复到额定速度并保持稳定。在切屑流流场内部的不同位置,切屑颗粒的速度存在差异。在同一时刻,切屑流中部的切屑颗粒速度最大,靠近刀齿部分速度次之,远离刀齿部分速度最小。随着铣刀转速的增加,切屑流的扩散角减小,在不同的木质复合材料铣削加工中,纤维板铣削过程中的扩散角最大,变化范围为533°~665°。
Abstract
Based on high speed rideo technology and image recognition technology, instananeous images of chip flow in the milling of wood based materials were collected and processed. The changes of the formation mechanism, the flow speed and diffusion angle of chip flow were analyzed by ProAnalyst Software. The results indicated that the formation procedure of the chip flow was divided into two stages. First stage was that the material of the cutting layer went away from the workpiece, and began to form the chip flow before touching the tooth gullet. Second stage was that the chip flow went away from the tooth gullet, and diffused in the air. The variety of chip flow speed was also divided into two stages. First stage was that the chip flow with a certain velocity from the work piece began to become reduced. Seconde stage was that the speed of the chip flow reached the peak value, and then trended to reduce in the air. When milling the wood based materials, the cutting tool was not in a stable rotation speed, with the tooth cutting in the workpiece, the speed of the tooth decreased to minimum value until the tooth got away from the workpiece. At this very moment of the tooth getting away from workpiece, the speed quickly restored and kept stability. Diffusion angle of chip flow would decrease with the increase of cutting speed.The diffusion angle of fiberboard milling is the biggest during the wood based materials milling in the range of 533°—665°.
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基金
收稿日期:2010-11-22修回日期:2011-05-17基金项目:国家自然科学基金项目(30871979);江苏高校优势学科建设工程资助项目(PAPD)作者简介:郭晓磊(1980—),讲师,博士生。*曹平祥(通信作者),教授。Email: caopx@njfu.com.cn。