Control method and system for automatically compensating pipe end liquid leakage in internal high pressure forming

Abstract

The invention discloses a control method and a system for liquid leakage from a pipe end in automatic compensation internal high pressure forming. The control method comprises obtaining the initial value of the total volume of liquid in a high pressure chamber of a supercharger, liquid in a pipe and liquid in a high pressure piping at the beginning of the internal high pressure forming; determining the compression amount of the total volume of the liquid according to the initial value of the total volume and the real-time pressure of the liquid in the pipe; determining the real-time volume of the liquid in the pipe; judging whether the real-time volume of the liquid in the pipe is larger than the final volume of a target formed part; if larger than the final volume, record leakage points, increase the axial feed amount of the pipe end to the pipe end for resealing, and finish the internal high pressure forming starting from the leakage point according to the preset displacement-internal pressure loading curve; if not, finish the internal high pressure forming according to the preset displacement-internal pressure loading curve. The leakage condition of the pipe end can be precisely judged by using the control method and the system disclosed by the invention, and automatic compensation is made through increasing the axial feed of the pipe end.

Description

technical field [0001] The invention relates to the field of pipe forming and processing, in particular to a control method and system for automatically compensating for pipe end liquid leakage during internal high pressure forming. Background technique [0002] Internal high pressure forming technology is an advanced pipe forming process. Its principle is to apply internal pressure and axial force to the pipe, so that the pipe is plastically deformed and attached to the mold cavity, and formed into a pipe fitting of the desired shape. [0003] The highest internal pressure in the high pressure forming process reaches 300MPa-400MPa, which must be provided by a supercharger. At the same time, it is necessary to match the internal pressure with the axial displacement to achieve the preset displacement-internal pressure loading curve. The internal pressure control principle is to indirectly control the liquid pressure in the high-pressure chamber of the supercharger by controll...

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Problems solved by technology

[0016] The liquid leakage generated during high pressure forming cannot be introduced into the closed volume, so this method cannot be used for leak detection

[0017] Patent CN201610673810.2 discloses a pipeline leakage detection system and its method. The distributed optical fiber temperature field measurement technology is used to detect pipeline leakage. The measurement device cannot be installed in the internal high pressure forming mold, so the leakage in the internal high pressure forming process cannot be detected. detection

[0018] The above liquid leakage detection method is only suitable for static pipeline leakage detection, and it takes a long time to detect the leakage. However, the pressurization process during internal high pressure forming is completed in a very short time, and the pressurization process is only 4s- 6s, the dynamic change of pressure is very fast, and the pressure detection methods in the prior art cannot be used for the detection of slight leakage that occurs during the internal high pressure forming process and cannot be judged from the pressure value

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