Pombo Iñigo, Sánchez José Antonio, Martin Einar, Godino Leire, Álvarez Jorge
Department of Mechanical Engineering, Bilbao School of Engineering, University of the Basque Country (UPV/EHU), 48013 Bilbao, Spain.
IDEKO S. Coop., 20870 Elgoibar, Spain.
Sensors (Basel). 2024 Mar 7;24(6):1741. doi: 10.3390/s24061741.
Due to the continuously growing demands from high-added-value sectors such as aerospace, e-mobility or biomedical bound-abrasive technologies are the key to achieving extreme requirements. During grinding, energy is rapidly dissipated as heat, generating thermal fields on the ground part which are characterized by high temperatures and very steep gradients. The consequences on the ground part are broadly known as grinding burn. Therefore, the measurement of workpiece temperature during grinding has become a critical issue. Many techniques have been used for temperature measurement in grinding, amongst which, the so-called grindable thermocouples exhibit great potential and have been successfully used in creep-feed grinding operations, in which table speed is low, and therefore, temperature gradients are not very steep. However, in conventional grinding operations with faster table speeds, as most industrial operations are, the delay in the response of the thermocouple results in large errors in the maximum measured value. In this paper, the need for accurate calibration of the response of grindable thermocouples is studied as a prior step for signal integration to correct thermal inertia. The results show that, if the raw signal is directly used from the thermocouples, the deviation in the maximum temperature with respect to the theoretical model is over 200 K. After integration using the calibration constants obtained for the ground junction, the error can be reduced to 93 K even for feed speeds as high as 40 m/min and below 20 K for lower feed speeds. The main conclusion is that, following the proposed procedure, maximum grinding temperatures can be effectively measured using grindable thermocouples even at high values of table speed.
由于航空航天、电动出行或生物医学等高附加值领域的需求不断增长，约束磨料技术是实现极端要求的关键。在磨削过程中，能量会迅速以热的形式耗散，在被磨削部件上产生以高温和非常陡峭的梯度为特征的热场。对被磨削部件的影响通常被称为磨削烧伤。因此，磨削过程中工件温度的测量已成为一个关键问题。许多技术已被用于磨削中的温度测量，其中，所谓的可磨削热电偶具有很大的潜力，并已成功应用于缓进给磨削操作中，在这种操作中工作台速度较低，因此温度梯度不是很陡峭。然而，在大多数工业操作那样的工作台速度较快的常规磨削操作中，热电偶响应的延迟会导致最大测量值出现较大误差。本文研究了对可磨削热电偶的响应进行精确校准的必要性，这是进行信号积分以校正热惯性的前期步骤。结果表明，如果直接使用热电偶的原始信号，相对于理论模型，最大温度偏差超过200K。使用为接地端获得的校准常数进行积分后，即使进给速度高达40m/min，误差也可降至93K，较低进给速度时误差可降至20K以下。主要结论是，按照所提出的程序，即使在工作台速度很高的情况下，使用可磨削热电偶也能有效地测量最大磨削温度。
