Development of the real time on-machine measuring system of grinding surface integrity

研制了一种能够实时测量机床表面完整性的新型传感器。该传感器可以测量磨削、切割、研磨、抛光等加工表面以下的残余应力分布、硬度分布和材料组织分布，传感器原型由激励线圈和检测线圈组成。它设置在传感器和工件之间的间隙，并在激励线圈、检测线圈和工件之间产生磁路。阐述了传感器的传感特性、影响测量精度的因素以及与X射线衍射仪测量值的比较。传感器的输出电压线性范围为2 mm，测量分辨率为20微米，可测量加工表面以下200微米范围内的残余应力分布。当该传感器检测到的表面完整性超出允许范围时，由计算机数字控制装置发出指令，停止数控程序，中断修整砂轮，或改变磨削条件，以在允许范围内获得良好的表面完整性。

The new sensor which can measure the surface integrity on the machine in the real time, has developed. The sensor can measure the residual stress distribution, hardness distribution and material structure distribution below the machining surface, such as grinding, cutting, lapping, polishing and so on.The prototype sensor consists of exiting coil and detecting coil. It is set with the gap between the sensor and workpiece and it is created the magnetic circuit between the exiting coil, detecting coil and workpiece. It can measure the residual stress, as the magnetic permeability of the workpiece material is in proportion to the stress of the machining surface.It has made clear that the sensing characteristics, the effect of factors on the precision of measuring, and the comparison of the measuring value by the X-ray diffraction meter.The sensor has a linearity of the out put voltage in 2 mm gap and the measuring resolution is 20 mum, and it can measure the residual stress distribution within 200 mum below the machining surface. And it has an enough ability such as the judgment machine of the surface integrity for the grinding system which control it in the real time.When the surface integrity measured by this sensor is over the permission level, the CNC (Computer Numerical Control) device give the command to stop the CNC program, and dress the grinding wheel by interrupt, or change the grinding condition in order to get the good surface integrity within the permission level.