CN109675967B

CN109675967B - Adjustable springback correction method

Info

Publication number: CN109675967B
Application number: CN201910021569.9A
Authority: CN
Inventors: 李洪洋; 宋明龙; 张丹丹; 曾申涛
Original assignee: Beijing Institute of Technology BIT
Current assignee: Beijing Institute of Technology BIT
Priority date: 2019-01-10
Filing date: 2019-01-10
Publication date: 2020-06-23
Anticipated expiration: 2039-01-10
Also published as: CN109675967A

Abstract

The invention belongs to the technical field of material processing, and relates to an adjustable springback correction method. The invention aims to design an adjustable springback correction device, namely, a set of hydraulic cylinder dot matrix is used for replacing a springback correction die to realize springback correction of different parts, the hydraulic cylinder dot matrix is symmetrically distributed on the upper part, the lower part, the left part, the right part, the front part and the rear part of the device, for the parts with different shapes, a shape cavity of the part to be corrected is constructed by adjusting the position of each hydraulic cylinder, then the part is placed in the cavity, and the position of each hydraulic cylinder is adjusted according to the springback quantity to press the part to a certain position and then fix the part, so that the purpose of correcting springback. The implementation method mainly comprises the following steps: designing an adjustable springback correction device, installing and fixing parts, adjusting the positions of all hydraulic cylinders to enable the parts to be fixed after forming a specific shape, unloading and taking out the parts after fixing a specific time, testing and evaluating the performance of the parts, and if parts with other shapes need to be replaced, only adjusting the positions of all the hydraulic cylinders.

Description

Adjustable springback correction method

Technical Field

The invention relates to a springback correction method of a stamping part, which is designed aiming at the cost problem of a springback correction die of the stamping part and can realize springback correction of various parts on an adjustable springback correction device.

Background

The plate forming is one of important branches in the material processing technology, the application is wide, 60-70% of steel products in the world are plates, and most of the steel products are pressed by overshoot. According to statistics, the added value which is equivalent to 12 times of the price of the raw materials is created after the sheet is formed. In the total value of national production, the related products of the formed plates account for about 1/4 of the total value. In the fields of automobiles, light industrial products, electronic products and the like, the stamped products comprise automobile bodies, chassis, oil tanks and the like, and further comprise iron core silicon steel sheets of electric appliances and the like, and the number of the iron core silicon steel sheets can reach 70% or more of the number of parts.

With the continuous rise of the mechanical manufacturing industry, the quality requirements of the stamping parts on the actual production practice are increased. During the stamping process, factors influencing the forming accuracy of the stamping part are many, and wrinkling, cracking and springback are three main defects in sheet stamping, wherein the springback is the most difficult to control. The rebound rule of stamping parts of different materials and shapes is greatly different because the accurate prediction of the rebound amount is involved. The forming precision and the surface quality of the stamping part can be influenced by the rebound problem, and when the rebound quantity exceeds the allowable tolerance, the stamping part becomes a forming defect, so that the quality and the precision of the stamping part are greatly influenced. The reason why the rebound is generated is as follows: in the process of stamping and forming of the metal plate, due to the fact that elastic deformation exists inside the metal plate, a workpiece tends to recover after being demoulded along with disappearance of external force, the shape of the expected die cannot be completely met, and the precision of the product is affected. According to the reason of the springback, namely elastic deformation, the springback cannot be eliminated, and only certain control measures can be taken from the engineering perspective. Because the rebound can not be completely eliminated, only a certain means can be adopted for control, so that two angles are adopted for controlling the rebound at present: (1) rebounding from the material against the stamping. The material is subjected to heat treatment in a certain mode before stamping, the stress condition is improved, and the rebound can be reduced to a certain degree. (2) Rebounding from the die structure against the flexure. If the first method is selected, some unnecessary processes are added, and the process cost is increased. The more economic mode is through improving the mould structure, reduces original resilience volume. However, most of the existing molds are rigid molds, namely specific molds need to be manufactured for one rebound part, the method is high in cost, the mold manufacturing process is too complex, and the production period of parts is long, so that the significance of researching a universal correcting device for the rebound parts with different shapes and sizes is very important.

In view of this, in order to provide a general solution for correcting different resilient members, reduce the time and cost for finding a specific mold or manufacturing the specific mold, and improve the production efficiency, the invention provides an adjustable resilient correcting device and a method for stamping by using the device.

Disclosure of Invention

The invention aims to provide a rebounding device which is reasonable in structure and arrangement, simple and convenient to operate and capable of conducting universal correction on rebounding problems of various rebounding pieces. Because resilience can't be avoided, can only be through taking certain means control or correcting the resilience, therefore, in order to save the processing cost, through the optimal design to resilience orthotic devices, compare in original orthotic devices that can only singly correct a resilience piece, can correct the resilience of the resilience piece of various shapes, the mould manufacturing cost that has significantly reduced can improve actual production efficiency to realize effectively correcting the resilience.

In order to achieve the technical aim, the invention adopts the following technical scheme to realize:

the adjustable springback correction device is simply put into a space formed by combining three groups of hydraulic cylinders (front and back, up and down, left and right) after stamping, the positions of the hydraulic cylinders in six directions are adjusted, acting force with a certain size is applied to the stamping through the hydraulic cylinders, the expected required shape of the stamping is obtained, and finally springback is adjusted.

The adjustable rebounding device comprises a rack, a workbench inside the rack and three groups of hydraulic cylinders symmetrically distributed in the three-dimensional direction, wherein the hydraulic cylinders are respectively connected with a material pressing core, and the rack is provided with a sensor and a control panel connected with the hydraulic cylinders and used for controlling the actions of the hydraulic cylinders and displaying the rebounding correction progress. The position of the hydraulic cylinder is set through the rebound quantity and the shape required by the stamping part, after the rebound quantity of the stamping part is determined and the position of the hydraulic cylinder is obtained, the workpiece is placed on the workbench, the position of the hydraulic cylinder is controlled, the three groups of hydraulic cylinders are located at expected positions, and finally, the three dimensions of the workpiece are subjected to acting forces of different sizes, so that the effect of correcting the rebound quantity in multiple directions is finally achieved.

Compared with the prior art, the invention has the following advantages:

(1) the method can be suitable for springback correction of stamping parts in different shapes, a matched springback correction device does not need to be additionally manufactured, and the process production cost is saved;

(2) the plastic rebound deformation generated in the stamping process of the stamping part can be corrected quickly and conveniently, the correction engineering is quick, and the production efficiency is greatly improved;

(3) the rebound of the stamping part is effectively corrected, and the production precision and the production quality are improved;

(4) the rebound part under the complex deformation state can be corrected, the realization can be realized only by controlling the displacement of the hydraulic cylinder, the complex production process is simplified, the application is wide, and the popularization of the adjustable rebound correcting device is facilitated.

(5) The device structure sets up rationally, easy operation can promote the product precision, produces high quality stamping workpiece, and application scope is wide, has reduced mould cost of manufacture, improves work efficiency, can both carry out the universalization to the resilience problem of the resilience piece of various shapes and correct, has very wide application prospect.

Drawings

Fig. 1 is a schematic diagram showing adjustable correction springback, wherein 4 represents a workpiece, 1, 2 and 3 represent three directions, hydraulic cylinders in the three directions are determined to correct the workpiece according to the shape of the workpiece, each point in the diagram represents a hydraulic cylinder capable of independently controlling the amount of motion, and hydraulic cylinder lattices in the up-down direction, the front-back direction and the left-right direction perform pressurization fixation on different positions of the workpiece to different degrees according to the shape of the workpiece and the springback amount, so that universal springback correction on different parts is realized.

Detailed Description

The specific implementation steps of correcting springback are as follows:

(1) and mounting the workpiece subjected to the stamping forming on a workbench, and then fixing the workpiece.

(2) After the proper movement positions of the hydraulic cylinders are designed according to the shape and the resilience of the stamping part, the three groups of hydraulic cylinders move through the piston rods to drive the material pressing cores connected to the hydraulic cylinders to move.

(3) The three groups of pressing cores are respectively pressed on the surface of the workpiece through coordinated movement, and meanwhile, constant acting forces in different directions are provided for different positions of the workpiece, so that the rebound correction of the stamping part is facilitated.

(4) After the correction is completed, the hydraulic cylinder moves to a position far away from the stamping part, the pressing core is driven to leave the workpiece, and the stamping part after the correction is convenient to take out.

(5) And measuring and evaluating the corrected sample, and if the corrected sample does not meet the expected requirement, adjusting the technological parameters such as the position and the pressure of the hydraulic cylinder until a part meeting the requirement is processed.

(6) When workpieces with other shapes need to be replaced and complicated rebounding stamping part correction is carried out, the three groups of hydraulic cylinders are correspondingly adjusted to move to a determined position, and the stamping parts are pressurized and fixed through the material pressing core, so that the rebounding correction on the complicated stamping parts with different shapes can be completed.

Claims

1. An adjustable springback correction method is specifically completed according to the following steps:

(1) installing the workpiece after stamping on a workbench provided with hydraulic cylinder lattices which are symmetrically distributed in the vertical, front and back directions and the left and right directions, and then fixing the workpiece;

(2) designing the movement positions of the hydraulic cylinders in six directions according to the shape and the resilience of the workpiece, moving the hydraulic cylinders to the specified positions, and driving the material pressing cores connected to the hydraulic cylinders to move by the hydraulic cylinders;

(3) the three groups of material pressing cores are respectively pressed on the surface of the workpiece through coordinated movement, and meanwhile, constant acting forces in different directions are provided for all positions of the workpiece to help the rebound correction of the workpiece;

(4) after the correction is finished, the hydraulic cylinder is moved to a position far away from the workpiece, the material pressing core is driven to leave the workpiece, and the corrected workpiece is convenient to take out;

(5) measuring and evaluating the corrected workpiece, and if the corrected workpiece does not meet the expected requirement, adjusting the position and the pressure of the hydraulic cylinder until a part meeting the requirement is processed;

(6) when workpieces with other shapes need to be replaced and complicated rebounding workpiece correction is carried out, the three groups of hydraulic cylinders are correspondingly adjusted to move to a determined position, the pressing core is driven to press the workpieces, and the rebounding correction on the complicated workpieces with different shapes can be completed;

the method is characterized in that a specific mould for correcting the rebound of the part conventionally is replaced by a hydraulic cylinder array which is flexibly adjustable in the upper, lower, left, right, front and back directions, a part-shaped cavity is constructed by adjusting the position of each hydraulic cylinder in the six directions, the part is placed in the hydraulic cylinder dot matrix cavity and is pressurized and fixed through each hydraulic cylinder to achieve the purpose of correcting the rebound, and in the method, the position and the pressure of each hydraulic cylinder are designed and controlled through a computer program.