CN111745026A

CN111745026A - Rubber forming method for deep drawing characteristic sheet metal part

Info

Publication number: CN111745026A
Application number: CN202010534886.3A
Authority: CN
Inventors: 李国栋; 谢永鑫; 张文卓
Original assignee: AVIC Shaanxi Aircraft Industry Group Corp Ltd
Current assignee: AVIC Shaanxi Aircraft Industry Group Corp Ltd
Priority date: 2020-06-12
Filing date: 2020-06-12
Publication date: 2020-10-09

Abstract

The invention discloses a method for forming a sheet metal part by using an eraser with a deep drawing characteristic, which comprises a forming device, wherein the forming device comprises a pressing die, a plastic plate and a soft rubber cushion, the shape of the working surface of the pressing die is consistent with the shape of the curved surface of the sheet metal part to be formed, the shape of the plastic plate is the same as that of the pressing die, the specific dimension of the plastic plate is less than 5mm, the thickness of the plastic plate can be 3-15mm according to the drawing depth of the formed part, and the plastic plate acts on widening a reinforcing ridge of the part under the condition that the drawing depth of the part is not changed, so that the groove width is reduced, the bending radius of the part is increased, the plastic plate is essentially equivalent to a set of transition die, and the plastic plate is removed after the plastic plate is used for assisting in forming the eraser to perform secondary hydraulic forming on the part. The part formed by the method has no cracks and has good forming integrity.

Description

Rubber forming method for deep drawing characteristic sheet metal part

Technical Field

The invention belongs to the technical field of metal pressure processing, relates to a method for forming a sheet metal part by using a rubber, and particularly relates to a method for forming a sheet metal part with a deep drawing characteristic by using a rubber.

Background

The rubber forming is a soft-die male (or female) forming method which uses a rubber bag as an elastic female (or male) die and uses liquid as a pressure transmission medium to form a metal plate along with a rigid male (or female) die. The part for forming the plate along the die is the rubber bag, and the other part for restraining the plate from forming is the rigid die. Compared with the traditional process method, the method has the advantages of complex formed parts, high surface quality and appearance accuracy, short production period and the like, and is suitable for the flexible development direction of small-batch and various aerospace products. But the rubber forming parts are mainly flanging parts, shallow drawing parts and dimpling parts due to the limitation of the flowing capacity of the rubber and the limitation of difficult blank pressing of the blanks. Generally, a method of drop forming or transition die hydroforming is usually adopted for deep drawing sheet metal parts, and the formed parts have poor surface quality, poor process stability and high manufacturing cost.

Disclosure of Invention

The invention overcomes the defects of the traditional forming process method of the sheet metal part with the characteristic of large deep drawing, and provides the method which can save the production cost, improve the quality of the part and achieve the effect of the same deep drawing depth as the traditional forming process.

The rubber forming method provided by the invention only needs to use a set of pressing die and a plastic plate to assist hydraulic forming, and can replace multiple hydraulic forming using a pressing transition die or semi-mechanical semi-manual drop forming, so as to achieve the effect of the same deep drawing depth. The forming method comprises a set of forming device which comprises a pressing die, a plastic plate and a soft rubber pad.

Technical scheme

A rubber forming method of a deep drawing characteristic sheet metal part comprises the following steps:

the method comprises the following steps: placing the plastic plate 2 on the press die 1, then placing the plastic plate on a hydraulic press workbench, and placing the unfolded woollen 3 on the upper surface of the plastic plate 2;

step two: setting the pressure value of the hydraulic press, utilizing hydraulic forming equipment to press down the rubber of the hydraulic press, and pressing the suspended wool 3 on the surface of the plastic plate 2 on the working surface of the pressing die 1 by the rubber of the hydraulic press to form a transition process piece.

Step three: and taking off the plastic plate 2, forming by using hydraulic forming equipment again, and compacting and wrapping the blank 3 on the working surface of the pressing die 1.

Further, in the first step, the plastic plate 2 is an auxiliary backing plate which can be reused according to production requirements.

The thickness t of the plastic plate 2 is 3-15mm according to the deep drawing depth h of the formed part, the purpose is to increase the bending radius of the part, reduce the stress concentration and store the material in advance, and the function is equivalent to a set of transition die.

Further, the pressure value of the hydraulic machine in the step two is 100 Bar.

The hydraulic press also comprises a soft rubber pad 6, wherein the soft rubber pad 6 covers the upper surface of the wool 3 and plays a role in protecting the surface of a part and the self-contained rubber of the hydraulic press.

And when the blanks 3 are cracked during secondary hydraulic pressure, completely annealing the blanks 3, and performing hydraulic forming again.

The shape of the plastic plate 2 is the same as that of the pressing die 1, and the size of the plastic plate is 5mm smaller than that of the pressing die 1, so that the plastic plate is used for positioning the shape of the part.

The shape of the blank 3 is the same as that of the pressing die 1, and the blank is 50mm larger than the shape of the pressing die 1 and is used for positioning the shape of a part.

Technical effects

1. The forming limit of the part is increased, the application range of the hydraulic technology is expanded, the original forming time is saved, and the production efficiency of the part is improved;

2. the invention solves the problem of integral forming of parts and improves the quality problem brought by the original forming method;

3. the invention solves the problem that a plurality of sets of equipment and tools are needed in the original forming mode, realizes that one set of die can complete part forming, and saves the manufacturing cost.

Drawings

FIG. 1 is a schematic view of an exemplary sheet metal part to be formed in accordance with the present invention

FIG. 2 is a schematic view of the forming principle of the present invention

FIG. 3 is a schematic diagram showing the relationship between the expanded wool and the mold according to the present invention

FIG. 4 is a schematic view showing the end of the rubber forming process of the plastic-padded plate of the present invention

In the figure: 1-pressing die, 2-plastic plate, 3-blank, 4-forming die fillet radius, 5-backing plastic plate preformed part bending radius, t-auxiliary plastic plate thickness and h-part nest depth.

Detailed Description

As shown in the attached drawings, the forming method comprises a forming die, wherein the forming die comprises a pressing die (1), a plastic plate (2) and a soft rubber cushion (6), the shape of the working surface of the pressing die (1) is consistent with the shape of the curved surface of the sheet metal part to be formed, the shape of the plastic plate (2) is the same as that of the pressing die (1), the size of the plastic plate is smaller than that of the pressing die (1) by 5mm, and the plastic plate is used for positioning the shape of the part. As shown in FIG. 2, for example, the radius (4) of the forming die is R, after a plastic plate with the thickness of 3mm is padded on the die, the R angle of the backing plastic plate preformed part bending radius (5) is changed into R +3mm, and the R angle is increased, so that the stress concentration is reduced, and the material flow is also facilitated. The curvature of a transition fillet is reduced at the bottom of the wool by utilizing a plastic plate, and the stress distribution area of the fillet is increased, so that the stress is dispersed and the displacement occurs.

The invention is described in further detail below with reference to the following detailed description and accompanying drawings:

the method comprises the following steps: the auxiliary plastic plate (2) with moderate thickness is placed on a pressing die and then placed on a hydraulic press workbench, the unfolding woolen (3) is placed on the upper surface of the plastic plate (2), and the soft rubber pad (6) is placed on the unfolding woolen (3) at the position of the pressing die (1). The thickness t of the plastic plate can be 3-15mm according to the drawing depth h of the formed part, and the plastic plate is used for increasing the bending radius of the part, reducing stress concentration and achieving the function of storing materials in advance.

Step two: setting the pressure value of the hydraulic press, pressing the suspended wool (3) on the surface of the plastic plate (2) on the working surface of the pressing die (1) by the self-provided rubber of the hydraulic press to form a transition process piece. The first hydraulic pressure is equivalent to that the reinforcing ridge of the part is widened by 6mm, the groove width is reduced by 6mm, and the depth h of the part nest is unchanged, so that 6mm of material is reserved in the depth direction of the reinforcing nest in advance, and the material is essentially equivalent to a set of transition die.

Step three: and (3) taking off the plastic plate (2), forming by using hydraulic forming equipment again, and compacting and wrapping the transition process piece on the working surface of the pressing die (1).

Claims

1. A rubber forming method for a deep drawing characteristic sheet metal part is characterized by comprising the following steps:

the method comprises the following steps: placing the plastic plate (2) on the pressing die (1), then placing the plastic plate on a hydraulic press workbench, and placing the unfolded woollen (3) on the upper surface of the plastic plate (2);

step two: setting a pressure value of a hydraulic machine, utilizing hydraulic forming equipment to press down a self-contained rubber of the hydraulic machine, and pressing the suspended wool (3) on the surface of the plastic plate (2) on the working surface of the pressing die (1) by the self-contained rubber of the hydraulic machine to form a transition process piece;

step three: and taking off the plastic plate (2), forming by using hydraulic forming equipment again, and compacting and wrapping the blank (3) on the working surface of the pressing die (1).

2. The method for forming the sheet metal part with the deep drawing characteristics according to claim 1, wherein in the step one, the plastic sheet material (2) is an auxiliary backing plate which can be reused according to production requirements.

3. The rubber forming method of the sheet metal part with the deep drawing characteristic as claimed in claim 1, wherein the thickness t of the plastic sheet (2) is 3-15mm according to the drawing depth h of the formed part.

4. The method for forming the sheet metal part with the deep drawing characteristic according to claim 1, wherein the hydraulic pressure value in the second step is 100 Bar.

5. The method for rubber forming of the sheet metal part with the deep drawing characteristic as claimed in claim 1, further comprising a soft rubber pad (6), wherein the soft rubber pad (6) covers the upper surface of the wool (3).

6. The method for rubber forming of a sheet metal part with deep drawing characteristics as claimed in claim 1, wherein the blank (3) is completely annealed and hydroformed again when the blank (3) is cracked during secondary hydraulic pressure.

7. The method for forming the sheet metal part with the deep drawing characteristic according to claim 1, wherein the plastic sheet (2) has the same shape as the pressing die (1), is 5mm smaller than the size of the pressing die (1) and is used for positioning the shape of the part.

8. The rubber forming method of the sheet metal part with the deep drawing characteristic according to claim 1, wherein the shape of the blank (3) is the same as that of the press die (1), and the size of the blank is 50mm larger than that of the press die (1) and is used for positioning the shape of the part.