Dynamics and Control of Grinding Machine with Micropositioning Workpiece Table

To improve the machining precision of a surface grinding machine, a micropositioning workpiece table with high performance was used as auxiliary infeed mechanism to implement nanometer level positioning and dynamic compensation. To better understand the characteristics of the grinding machine modulated with micropositioning workpiece table, the dynamic model of the grinding system was established with modal synthesis and Lagrange's equation methods. The grinding system was divided into five subsystems. For each subsystem, the generalized kinematic and potential energies were obtained. Accordingly the dynamic model of the grinding system was given in the modal domain. The waviness of the grinding process was achieved based on the wheel and workpiece vibration. A nonlinear proportional integral derivative (PID) controller with differential trackers was developed to realize dynamic control. The simulation results show that the machining accuracy of the workpiece can be effectively improved by utilizing the micropositioning workpiece table to implement dynamic compensation. An experimental test was carried out to verify the proposed method, and the waviness of the workpiece can be reduced from 0.46 μm to 0.10 μm.     

用CNC工具磨床修磨尖齿成形铣刀

文章论述了用ＣＮＣ工具磨床对尖齿成形铣刀刃型的成形与修磨方法，给出了刀齿任意点法向后角计算公式与修磨中应注意的几个问题。     

为每一个学生提供适合的教育

别具一格的学校雕塑瞬间吸引了我,这是三个形状相同,大小不同的内圆外方雕塑,这是"十一"学校"思圆行方"办学理念的外化。但是我很疑惑,为什么这和中国传统文化是相反的?古代无论是最初的铜钱还是做人,都讲求外圆内方。这个问题是毛校长帮我解决的,她的观点是:这展示着他们办学对传统课堂的颠覆,培养棱角分明,个性化学生的育人愿景。我觉得很有道理,中国人讲求中庸、内隐,不愿表达和展示自己。这显然和今天社会发展的需求相悖,北京"十一"学校让我又重新理解我们的教育,人应该多元学习,丰盈自己的人生,让自己变得更加圆满。但人与人之间又具有个体差异性,