Development of Rapid In-process Measurement of Surface Roughness for In-line Total Check of Surface Quality

表面光洁度通常由跟踪针速较低的表面粗糙度测试仪测量，速度为每秒零点几毫米。因此，通过验收抽样，仅根据少数零件的测量结果来判断该批次制造的所有零件的表面光洁度。提出了基于热电效应的旋转磨削加工表面光洁度在线检测新技术，研制了表面光洁度快速在线检测系统。在磨削加工过程中，工件表面的温升影响到所研制的传感器的输出，该传感器具有一对平行的分离的热电偶丝，并具有一定的张力。为了用工件表面温升消除信号分量，提取估算表面粗糙度的分量，我们提出了两种消除方法，并对它们的有效性进行了实验研究。结果表明，我们成功地测量了外圆插拔磨削过程中表面粗糙度的变化。其他结论如下。1.研制的热电偶丝接触式传感器的输出与表面光洁度近似呈线性关系。2.灵敏度随测量速度、工件周向速度的增加而提高，在测量速度约为表面粗糙度测试仪测量速度的两千倍时，系统可获得表面光洁度。3.采用较粗的传感器热电偶线，提高了灵敏度。4.本测量系统需要施加较大的测量载荷，使热电偶丝与工件表面保持稳定接触。此外，测量负载在0.98N时的灵敏度高于在0.29N时的灵敏度。

The surface finish is generally measured by the surface roughness tester with lower tracing stylus speed of zero point several millimeters per second. Therefore, the surface finish of all parts manufactured in the lot is judged based on the measured results of only few parts by the acceptance sampling. We propose the novel on machine measurement technique of surface finish with the thermoelectric effect for rotating ground workpiece and the rapid on machine measurement system of surface finish is developed. In a grinding process, the temperature-rise of workpiece surface affects the output of developed sensor, which has a pair of parallel separate thermocouple wires with a certain tension. In order to cancel the signal component by a temperature-rise of workpiece surface for an extraction of component estimating surface roughness, we developed two kinds of cancellation methods and experimentally investigated their availability As a result, we have successfully measured a variation of surface roughness in a cylindrical plunge grinding process. Other conclusions are follows. 1. The output from the developed contact sensor with thermocouple wires approximately has the liner relationship with surface finish 2. The sensitivity improves with an increase of measuring speed, peripheral speed of workpiece, and the system can obtain the surface finish at the measuring speed which is about two thousands times as large as that of surface roughness tester. 3. The sensitivity improves by use of thicker thermocouple wires of sensor. 4. It is necessary for this measurement system to apply the measuring load so large that thermocouple wires keep steady contact with workpiece surface. In addition, the sensitivity at 0.98 N in measuring load is higher than that at 0.29N.