Machine vision micro-milling tool wear inspection by image reconstruction and light reflectance

• A method for micro-tool EDoF image reconstruction based on wavelet transform was proposed.
• The abrasive character of tool wear changes the tools reflectance in wear regions.
• An inspection method using light reflectance and the EDoF approach for tool wear assessment was proposed.
• The tool wear inspection method was tested against SEM inspection providing good results.

The paper presents a method for micro-milling tool wear inspection using machine vision. An original Wavelet-based Extended Depth of Field image reconstruction is proposed. The method enables geometrical measurements required to locate the cutting edges of the micro-tool. In the proposed method, variable light intensity is used during image acquisition to detect regions of different reflective properties. Geometrical information and reflective properties are then used to evaluate the tool wear. The proposed method is introduced to a prototype inspection machine. The results were compared to SEM images creating interesting conclusions.