A self-adaptive control method for springback of sheet metal under pressure forming in viscous medium

An adaptive control and viscous medium technology, applied in the field of plate forming, can solve the problems of long springback time, limited improvement of dimensional accuracy and high cost, and achieve the effect of saving mold repair

Active Publication Date: 2020-05-12
HARBIN INST OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The current springback control methods, on the one hand, control the springback to a certain extent by optimizing various process parameters such as blank holder force, lubrication conditions, and slab shape, and on the other hand, control the springback by optimizing the mold surface. Compensation, but at present these methods take a long time to control the springback effect, the cost is high, and the dimensional accuracy is limited. It is impossible to control the springback from the root cause. It is necessary to explore the pressure control of the forming process to suppress the springback during the forming process. Methods

Method used

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  • A self-adaptive control method for springback of sheet metal under pressure forming in viscous medium
  • A self-adaptive control method for springback of sheet metal under pressure forming in viscous medium
  • A self-adaptive control method for springback of sheet metal under pressure forming in viscous medium

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0046] Embodiment 1: Choose a regular spherical concave mold 1.

[0047] 1. The material of slab 2 is stainless steel 304, 1.02×10 -3 Time,

[0048] The size of P is 130MPa; and when the viscous medium 4 is selected, the strain rate sensitivity index m is 0.1, ΔP is 25-27MPa, V 1 =0.8mm / s, V 2 Under the condition of =0.1mm / s, the duration t only needs to be 5s, and the sheet blank 2 can be formed without springback;

[0049] 2. The material of slab blank 2 is aluminum alloy AL1060, 1.81×10 -3 Time,

[0050] The size of P is 70MPa; and when the viscous medium 4 is selected, the strain rate sensitivity index m is 0.5, ΔP is 13~18MPa, V 1 =0.3mm / s, V 2 =0.01mm / s, the duration t only needs to be 7s, and the sheet blank 2 can be formed without springback;

[0051] 3. The material of slab blank 2 is high temperature alloy GH4169, 2.75×10 -3 Time,

[0052] The size of P is 150MPa; and when the viscous medium 4 is selected, the strain rate sensitivity index m is 0.9, ΔP is 6-8MPa, V 1 =0.1mm / ...

Embodiment 2

[0053] The second embodiment: The concave mold 1 with a stepped shape is selected, and the material of the blank 2 is aluminum alloy AL1060, 1.81×10 -3 When the value of P is 80MPa; and when the viscous medium 4 is selected, the strain rate sensitivity index m is 0.5, ΔP is 11MPa, V 1 =0.2mm / s, V 2 Under the condition of =0.06mm / s, the duration t only needs to be 8s, and the sheet blank 2 can be formed without springback;

Embodiment 3

[0054] The third embodiment: the die 1 in the shape of a variable diameter member is selected, and the material of the slab 2 is high temperature alloy GH4169, 2.75×10 -3 When the value of P is 170MPa; and when the viscous medium 4 is selected, the strain rate sensitivity index m is 0.9, ΔP is 5MPa, V 1 =0.1mm / s, V 2 Under the condition of =0.005mm / s, the duration t only needs to be 8s, and the sheet blank 2 can be formed without springback.

[0055] In summary, the present invention utilizes the strain rate sensitivity of the viscous medium 4, and its pressure can adapt to the change of the sheet shape. In the pressure forming of the viscous medium 4, by controlling the unloading method of the viscous medium 4 during the unloading process, the formed part is During the unloading process, the mold is repeatedly applied and the residual stress is gradually released, and the internal stress gradient of the final molded part is reduced. Not only can it achieve the purpose of controll...

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Abstract

The invention relates to a plate viscous medium pressure forming rebound self-adaptive control method. The plate viscous medium pressure forming rebound self-adaptive control method comprises the following steps that I, fixing a medium bin, installing a plunger in the medium bin, and injecting a viscous medium into the medium bin; II, placing a plate blank at the top of the medium bin, then installing a female die on the plate blank and is fixing the female die, so that clamping the plate blank between the medium bin and the female die; III, pushing the plunger in the medium bin to move upwards at the speed V1, gradually attaching the plate blank to a cavity of the female die, and being the pressure P in the medium bin; IV, enabling the plunger to move downwards at the speed V2, so that reducing the pressure in the medium bin to be P1, meanwhile, stopping moving the plunger downwards, so that keeping constant the pressure P1 in the medium bin, and being the duration time t; and V, after lasting the pressure p1 for the duration t, moving the plunger downwards again at the speed V2 until completely unloading the viscous medium. The plate viscous medium pressure forming rebound self-adaptive control method has the advantages that a forming part can be repeatedly stuck the die in the unloading process and the residual stress is gradually released, so that the resilience is controlled.

Description

Technical field [0001] The invention relates to the technical field of sheet metal forming, in particular to an adaptive control method for the springback of sheet viscous medium pressure forming. Background technique [0002] After the sheet is stamped, formed and unloaded, springback will occur. The essence of springback is that the internal stress distribution of the sheet is uneven after the sheet is formed. During the unloading process, the stress field caused by the release of the internal residual stress of the formed part re-establishes the balance process, so the rebound is The size depends on the internal stress state of the formed part before springback and the geometry of the formed part. At present, springback is a widespread phenomenon in sheet metal plastic forming, which seriously affects the size and shape accuracy of stamping parts, and is an urgent problem in the industry and academia. The current control methods for springback are, on the one hand, controllin...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): B21D26/027
CPCB21D26/027
Inventor 王忠金冯业坤杨继平
Owner HARBIN INST OF TECH
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