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

表面光洁度一般用表面粗糙度仪测量，跟踪针速度较低，零点每秒几毫米。因此，该批次中制造的所有部件的表面光洁度仅根据少数部件的验收抽样测量结果进行判断。提出了基于热电效应的旋转磨削工件表面光洁度在线检测技术，并研制了表面光洁度在线快速检测系统。在磨削加工过程中，工件表面的温升会影响传感器的输出。为了消除由工件表面温升引起的信号分量，提取表面粗糙度分量，我们提出了两种消除方法，并通过实验研究了它们的有效性。结果，我们成功地测量了外圆切入磨削过程中表面粗糙度的变化。其他结论如下。1.所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。该系统的灵敏度随测量速度、工件圆周速度的增加而提高，测量速度约为表面粗糙度仪的2000倍。3.传感器采用较粗的热电偶丝，提高了灵敏度。4.该测量系统需要施加足够大的测量载荷，使热电偶丝与工件表面保持稳定接触。此外，在0.98N载荷下的灵敏度高于0.29N载荷下的灵敏度。

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.