Modeling method of molten-pool light intensity data field detected by photodiode

Abstract

The invention discloses a modeling method of a molten-pool light intensity data field detected by a photodiode. The method comprises the steps of: grid dividing, wherein regular grid dividing is carried out on a machining cross-section of each layer of a forming member according to sampling frequency of a detecting circuit to enable each grid to correspond to a coordinate value; matrix establishment, wherein a two-dimensional matrix is established, and each unit of the matrix corresponds to a cross-section grid position; coordinate correspondence, wherein molten-pool light intensity data are enabled to correspond to coordinate data of the cross-section grid positions according to laser scanning speed, and the corresponding matrix units are filled with the molten-pool light intensity data;and image display, wherein molten-pool light intensity data values in the two-dimensional matrix are converted into spatial-domain visualization signals. According to the method, distribution and variation of molten-pool light intensity on the forming layer can be intuitively observed, difference of the molten-pool light intensity can be reflected according to difference of RGB colors, generationof defects such as holes, depressions and cracks can be distinguished, and research of defect generation mechanisms and an effect of realizing online feeding-back through adjusting laser parameters are facilitated. The method is simple and versatile, and easy to promote.

Description

1. Technical field [0001] The invention belongs to the technical field of data image processing, in particular to a method for modeling a melting pool light intensity data field detected by a photodiode. 2. Background technology [0002] Selective Laser Melting / Selective Laser Sintering (SLM / SLS) is an additive manufacturing technology developed in recent years. Forming parts with specific geometric shapes has the advantages of high precision, high material utilization, good compactness of parts, and simple process. Metal materials have been maturely applied in this technical field, but defects such as warpage and deformation are still common problems in the forming process. The SLM / SLS forming technology of ceramic materials is in the research stage, and defects such as cracks and pores that affect the performance of parts need to be resolved urgently. The SLM / SLS forming process was studied from the thermal behavior of the molten pool. Monitoring the molten pool during ...

AI Technical Summary

Problems solved by technology

[0003] Photodiode detection of molten pool light intensity is a mature method for online detection of molten pool. It can reflect the current light intensity information of molten pool in real time by converting the optical radiation signal of the molten pool during the melting process of the material into a voltage signal. Compared with high Due to the high cost and difficulty of promotion of detection methods such as frequency cameras and infrared thermal imaging cameras, photodiode online monitoring is an economical and effective detection method. However, the information obtained by photodiode detection is a signal in the voltage time domain, which cannot be compared with the spatial domain The molten pool size, temperature and other information directly correspond to each other, and it is impossible to visually observe and compare the changes of the molten pool on the entire processing plane.

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