| 摘要 |
PURPOSE:To apparently indicate a crack to be scarcely discriminated from a weld and to rapidly and easily detect a defective product by embossing the lower surface of a flange. CONSTITUTION:A lower surface 4a of a flange 4 of a reel hub 2 is roughly embossed to form an uneven part of 2 - 8mum at the surface 4a of the flange 4. In this case, since the visibility of a weld generated at the hub 2 and the visibility of the embossed surface are in the same degree, the weld is erroneously seen as the embossed surface. As a result, a crack having higher visibility than that of the weld is apparently seen. Thus, a defective product can be rapidly and easily detected. |
