Touch monitoring and feedback compensation layer height control system and method for additive manufacturing

Abstract

The invention relates to a touch monitoring and feedback compensation layer height control system and method for additive manufacturing. According to the technical scheme provided by the invention, the process experiment difficulty is reduced, and meanwhile, the processing precision and the measuring precision in an additive manufacturing process are improved. The system comprises a numerically controlled machine tool, a laser cladding head, a touch three-dimensional measuring head, a touch measuring probe calibrating standard ball, a milling tool and a base plate, wherein the base plate and the touch measuring probe calibrating standard ball are mounted on the working plane of the numerically controlled machine tool; the touch three-dimensional measuring head has two integrating modes: (1) the milling tool, the laser cladding head and the touch three-dimensional measuring head are converted automatically on a spindle of the numerically controlled machine tool; and (2) the milling toolor the laser cladding head and the touch three-dimensional measuring head are arranged in parallel at the spindle end of the numerically controlled machine tool. The method comprises the following steps of 1, original calibration measurement of the touch three-dimensional measuring head; 2, calculation of the scanning velocity V and the sampling density T of the touch three-dimensional measuringhead; and 3, layer height compensation printing.

Description

technical field [0001] The invention belongs to the research field of additive manufacturing processing technology, and in particular relates to a tactile monitoring and feedback compensation layer height control system and method for additive manufacturing. Background technique [0002] At present, additive manufacturing technology has been applied in the machining industry, but only relying on additive manufacturing technology to print workpieces, its surface quality and dimensional accuracy are generally poor. research hotspots in the industry. However, in the process of cross-switching between adding and subtracting materials, whether the printing layer height of the workpiece meets the requirements, under what circumstances to continue to add material printing, under what circumstances to call the milling tool for size correction, and the amount of compensation have not yet been clearly resolved. Way. [0003] 1. Chinese patent CN204224703U discloses a three-dimension...

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Problems solved by technology

However, the technology disclosed in this patent has the following defects: laser milling is expensive, and the separate arrangement of laser cladding and laser milling results in a decrease in work efficiency; and the temperature of the printed workpiece is not considered. The temperature of the molten pool is as high as thousands of degrees Celsius at the moment of laser cladding. Non-negligible thermal deformation of the printed workpiece

[0007] In the three existing patent documents 2, 3, and 4 described above, none of the disclosed technical solutions takes into account the thermal deformation problem in the additive manufacturing process. In the actual additive manufacturing process, laser cladding and Take the axial powder feeding process as an example. The temperature at the molten pool is as high as thousands of degrees. Even after cooling for a few minutes, the temperature is still seventy to eighty degrees. Considering the linear expansion factor of the material, the workpiece is printed according to the temperature increase of 2° There is an error of about 0.01mm in the length direction for every 1m. It can be seen that thermal deformation is a problem that cannot be ignored. Thermal deformation will greatly affect the processing accuracy and measurement accuracy in the process of additive manufacturing.

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