Research On Processing And Quality Inspection Technique Of Laser Direct Part Marking2D-barcodes On Surfaces Of Aluminum Alloy

With the advantages of non-contact working, high repeatability, high scanning speed, high flexibility and automation, laser marking, one technology of direct part marking (DPM), has been widely applied to products identification and management in all aspects of electronic information, machinery manufacturing, etc. Aluminum alloy is one of the most widely used metallic materials in industry. It is difficult to get high quality Data Matrix (DM) barcodes by laser marking on the surface of uncoated or non-anodized aluminum alloys. In order to solve this problem, researches on processing and quality inspection technique of laser marking DM barcodes on surfaces of aluminum alloy were carried out as follows:The rules and effects of single laser processing parameter on the DM barcodes’ processing quality were studied. The action principle of processing parameters (filling space, current intensity, scanning speed, Q frequency) on the laser marking DM barcodes’processing quality which includes the surface roughness of DM barcodes, marking depth, marking width and processing time were analyzed. Several single-factor experiments were carried out on6061aluminum alloy sheets. Based on the experimental results, the effects of processing parameters on the DM barcodes’surface roughness, processing time, marking depth, marking width were investigated.The influences of processing quality on image quality of laser direct marking DM barcodes were analyzed. The effects of laser marking width on the print growth, the oxidation rate and surface roughness of laser marking area on the symbol contrast were studied. The effects of laser direct marking DM barcodes’processing quality on image quality were further verified by experimental data A phenomenon was discovered that the "White" and "black" DM barcodes were more suitable for laser direct part marking on6061aluminum alloy.The optimal parameters for producing "white" and "black" DM barcodes were obtained. In order to determine the optimum processing conditions to produce a scannable barcode, the Taguchi method was introduced in the experiment. The optimization analysis for producing "white" and "black" DM barcodes were carried out by using signal to noise ration on definite purpose. The optimal parameters combination of filling space, current intensity, laser scanning speed, pulse frequency for processing "white" and "black" DM barcodes were obtained.The nonlinear regression model of the laser direct marking DM barcodes’ processing quality and processing parameters was established. The methods and modeling tools for establishing mathematical models were investigated. After analysis of the nonlinear regression models between the DM barcodes’surface roughness and each processing parameters (filling space, current intensity, laser scanning speed, Q frequency) by using SPSS(Statistical Product and Service Solutions) and MATLAB (matrix&laboratory), the final nonlinear regression model was established to formulate the relationship between all of the four processing parameters and surface roughness. The model was finally proved to be reliable by verifying experiments.The study was supported by Promotive Research Fund for Excellent Young and Middle-aged Scientists of Shandong Province (BS2012ZZ005).