Real-time measurement method and device for deformation of formed part in additive manufacturing process

Abstract

The invention relates to a real-time measurement method and device for deformation of a formed part in an additive manufacturing process. The method comprises the steps of: 1, initializing the measurement device; 2, determining the position of a measurement point; 3, starting forming a component on a substrate, starting distance measurement when forming is beyond the position of measurement point and a laser distance measurement instrument is capable of receiving a self-measured light beam signal, and stopping the measurement when part forming is accomplished and the temperature falls below an indoor temperature; 4, obtaining a real-time displacement at the position of the measurement point on the part in the forming process according to distance measurement data of adjacent moments, obtaining a real-time deformation curve at the position of the measurement point in the part additive manufacturing process according to the relationship between the displacement and time; and 5, adopting a plurality of laser distance measurement instruments, carrying out steps from 1 to 4 simultaneously on each laser distance measurement instrument, and performing deformation measurement on a plurality of points on the formed part, thereby obtaining the real-time deformation curve at a position corresponding to each laser distance measurement instrument of the formed part in additive manufacturing process.

Description

technical field [0001] The invention relates to the technical field of additive manufacturing, in particular to a method and device for real-time measurement of deformation of formed parts during additive manufacturing. Background technique [0002] At present, additive manufacturing technology, as an emerging field in the manufacturing industry, has made great progress. The basic principle is: firstly generate the 3D CAD model of the formed part in the computer, and then use layered slicing software to slice the formed part model according to a certain thickness, that is, convert the 3D shape information of the formed part into a series of two-dimensional contour information , and then use a specific heat source such as a high-energy beam to heat and melt the material. Under the control of the numerical control system, the material is piled up point by point according to a certain filling path to a given two-dimensional shape, and this process is repeated to form a three-di...

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Problems solved by technology

On the one hand, this is very different from the constraints of the actual additive manufacturing substrate; on the other hand, there is a lack of experimental verification of direct real-time measurement of the deformation of the formed part

Another study reported that the deformation of the substrate was measured using the plaster inversion method (Yu Jun. Research on the Basic Issues of Laser Stereoscopic Forming Process Control. Doctoral Dissertation of Northwestern Polytechnical University, 2010), that is, the plaster inversion of the substrate was made with the substrate as a model. The spiral micrometer measures the height difference between the two ends and the center of the gypsum mold to evaluate the degree of warpage of the substrate. The disadvantage of this method is manual measurement, which has low measurement accuracy and large errors; the second is only to measure the substrate after the fact. Deformation, without measuring the real-time deformation of the formed part, the post-measurement can only get the final result of the deformation, but cannot reveal the detailed process of the deformation during the forming process

In the field of welding technology, some researchers are carrying out butt welding of two steel pipes (ZhangJianxun, LiuChuanandNiuJing. th International Conference on Nuclear Engineering, May17-21, 2010, Xi'an, China), using a linear variable displacement sensor to measure the deformation during the welding process, the accuracy is a few tenths of a millimeter, which is significantly improved compared to manual measurement, but this method is contact For measurement, sensors need to be installed on the forming part in advance, and in the process of additive manufacturing, the forming part is just a three-dimensional computer model at first, and the material is stacked layer by layer on the substrate by melting the material with high energy beam. The inconvenient nature of tactile measurements during manufacturing and the harsh conditions near the high-energy beam machining area prevents close proximity of the sensors, limiting the application of tactile measurement methods in the field of additive manufacturing

Generally speaking, in the current field of additive manufacturing, the measurement of part deformation is carried out after the forming is completed, and there is no real-time measurement method for deformation, which will lose the deformation law of the part during the forming process

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