ترموگرافی مادون قرمز به عنوان یک روش جدید برای کنترل کیفیت ورق قطعات فلزی در مغازه مطبوعاتی

Active dynamic thermography was proved to be a new alternative for crack detection. To achieve zero failure sheet metal production in the press shop, this method was investigated for different steel components, which were directly collected from series production. And the cracks in the presented specimens differ in length and in depth, and a series study on these surface cracks is executed. The crack detection capabilities of active thermography with two different excitation sources were compared: optical and inductive excited thermography. Results of experiments obtained by these two techniques are showed and compared with each other. Opportunities of applying these methods in press shop are discussed.

Infrared thermography (IRT) was at first an invention for military applications. However, due to the rapid development of thermal cameras since the 1970s, this technology has been increasingly used in civilian areas. Because of its several advantages, such as non-contacts with the inspected object and detection capability of subsurface failure [7], IRT is widely applied for nondestructive testing (NDT). Furthermore, materials with either low or high thermal conductivity are able to be detected using IRT with proper mathematical evaluations [7] and [11]. For example, cracks or impact of lamination. Furthermore, IRT system requires very short testing time, which enable its application on automatic quantitative material defects detection [1], [2] and [7]. These properties of IRT also match the requirements of quality control systems for sheet metal parts, and it can be a solution for an automated defects detection system in the press shop. In this paper, two of the most common IRT techniques will be introduced, which are the optical and inductive excited pulsed-phase thermography (PPT). Specimens for the experiments are collected and cut off from the series production of luggage trunk door. Detection results of defects with these two IR techniques were compared, in order to approach a better suitable method for quality controlling of specific sheet metal parts.

This paper aims to present a new method for quality controlling of sheet metal parts. Experiments have also proved the feasibility of using inductive excited PPT as a better solution, alternatively to only visual inspection conducted by human beings in press shop. Further investigations are suggested to complete this quality control procedure.