CN110756638A

CN110756638A - Secondary stamping forming process based on ultrasonic vibration assistance and amplitude transformer structural design

Info

Publication number: CN110756638A
Application number: CN201910845098.3A
Authority: CN
Inventors: 何云生; 解加庆; 张硕; 崔轶立; 高鹏; 陈军; 周天丰
Original assignee: Northwest A&F University
Current assignee: Northwest A&F University
Priority date: 2019-09-07
Filing date: 2019-09-07
Publication date: 2020-02-07

Abstract

The invention provides a secondary stamping forming process based on ultrasonic vibration assistance and a structure design of a variable amplitude rod, and belongs to the technical field of metal forming manufacturing processes. The process method and the amplitude transformer structure provided by the embodiment of the invention can reduce the interface friction force between the workpiece and the die, can better eliminate the internal stress of the part, and improve the processing precision and efficiency of the thin-wall part.

Description

Secondary stamping forming process based on ultrasonic vibration assistance and amplitude transformer structural design

Technical Field

The invention relates to the technical field of metal forming manufacturing processes, in particular to a process scheme for realizing high-precision manufacturing of parts by applying ultrasonic vibration to assist a secondary stamping forming process on the basis of metal stamping forming, and relates to corresponding structural design and application of a horn.

Background

In the metal plastic forming process, the key problems of research are that various composite forming processes are adopted to reduce the metal deformation resistance and increase the plastic deformation capacity of metal materials. In the metal plastic forming process, the auxiliary ultrasonic vibration is applied, so that the deformation resistance of the metal material is reduced, the interface friction force between the workpiece and the die is reduced, and the forming quality and the surface quality of the metal material are improved, so that the ultrasonic-assisted plastic forming becomes a typical plastic composite forming process.

Disclosure of Invention

Based on the technical background and through improvement, the process comprises the following two steps: the first step is to adopt hydraulic servo or electric servo punching to deform the metal piece to form a part blank; and the second step is to apply 20-30KHz ultrasonic wave to carry out secondary forming on the punched part, aiming at improving the processing precision and efficiency of the thin-wall part and eliminating stress concentration. The principle of the process is shown in figure 1.

The stamping mode included in the process can be selected according to the characteristics of the part, and the ultrasonic auxiliary vibration can be matched with the part to work.

The amplitude transformer is a step-type amplitude transformer, the size of the amplitude transformer adopts half-wavelength size, the material of the amplitude transformer is steel, the amplitude transformer works at the frequency of 20-30KHz, the amplitude transformer is in a 10 th-order mode, the amplitude of the amplitude transformer expands and contracts along the axial direction, the amplification coefficient of the amplitude transformer is larger than 2, and when the amplitude of an input end is 5 micrometers, the amplitude of an output end can reach more than 10 micrometers. The specific structure is shown in fig. 2.

Drawings

FIG. 1 is a schematic view of the principle of applying ultrasonic wave to assist the secondary punching process.

Reference numerals: 1-a workpiece; 2-a tool head; 3-a horn; 4-a transducer; 5-ultrasonic generator.

Fig. 2 is a structural design drawing of a horn.

Reference numerals: a small end diameter d1 (mm); the large end diameter d3 (mm); flange diameter d2 (mm); stud diameter d4 (inch); die length L1 (mm); a small end length L2 (mm); a large end length L3 (mm); flange thickness t (mm).

FIG. 3 is a flow chart of example 1.

FIG. 4 is a flow chart of example 2.

Reference numerals: 6-a male die; 7-parts; 8-horn and tool head; 9-die or jig.

Detailed Description

The invention is supplemented by the combination of the structure design of the amplitude transformer and the process. According to the matching processing of the corresponding amplitude transformer structure in the figure 2, it is worth noting that the standard amplitude transformer structure is a determining factor for the success of the process, the processing precision requirement is high, and the quality requirement must be ensured. And then, the corresponding tool head is matched according to the design requirements of specific parts, and the tool head has the same higher dimensional precision and material requirements.

Firstly, stamping a part in a hydraulic servo or electric servo stamping mode to form a part blank. The second step is to secondary form the stamped part by applying ultrasonic vibration. As shown in figure 1, a tool head 2 is additionally arranged on an amplitude transformer 3, the amplitude transformer 3 is connected with an ultrasonic transducer 4, the ultrasonic transducer 4 is connected with an ultrasonic sounder 5 through a data line to work, a part blank is subjected to finish machining, the pressure and the feed amount in the machining process are determined by the design requirements of the part, and are controlled by an external servo motor or a hydraulic device and the like. The times and time of the secondary ultrasonic auxiliary punching are determined according to the procedures and effects of the parts. In particular, in any step of the process, the clamping and positioning precision of the part must be strictly controlled. And the process can support secondary clamping during secondary forming, and does not influence processing.

Example 1

The embodiment provides a stamping forming process assisted by ultrasonic vibration controlled by an electric servo, which comprises the following steps:

1.1, selecting a die and a clamp which are required by stamping and correspond to the size of a part;

1.2, selecting a proper position for positioning and clamping the plastic metal plate, controlling the punching force required by the part and the feeding amount of each time by an electric servo to form a part blank, and reserving a certain machining allowance for secondary forming;

1.3, selecting a proper ultrasonic auxiliary vibration tool head, and finely adjusting and processing each part of the part by electric servo and ultrasonic auxiliary vibration to finally form a standard part.

The electric servo and the ultrasonic vibration are combined into a whole, the tool head needs to be machined at each position needing stamping deformation, and the corresponding tool head needs to be replaced at different positions.

Example 2

The embodiment provides a secondary forming process capable of being clamped for the second time and assisted by ultrasonic vibration under hydraulic servo control, which comprises the following steps of:

1.1, selecting a die and a clamp which are required by stamping and correspond to the size of a part blank;

1.2, selecting a proper position for positioning and clamping the plastic metal plate, controlling the required punching force and the feeding amount of the part blank by a hydraulic servo to form the part blank, and reserving a certain machining allowance for secondary forming;

1.3, replacing a part mould, replacing a clamp and carrying out secondary clamping;

1.4, selecting a proper ultrasonic auxiliary vibration tool head, and finely adjusting and processing each part of the part by hydraulic servo and ultrasonic auxiliary vibration to finally form a standard part.

Wherein, because changed the mold processing and carried out the secondary clamping, the clamping precision needs strict control, and the secondary forming ultrasonic vibration auxiliary assembly of this embodiment is at the opposite side of terrace die, the back work of part promptly, and the instrument head need not to be changed again, but also need remove in different processing position departments.

In conclusion, the ultrasonic vibration assisted secondary forming process provided by the embodiment of the invention can reduce the interface friction force between the workpiece and the die, can better eliminate the internal stress of the part, and improves the processing precision and efficiency of the thin-wall part.

The embodiments described above are some, but not all embodiments of the invention. The detailed description of the embodiments of the present invention is not intended to limit the scope of the invention as claimed, but is merely representative of selected embodiments of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments of the present invention without any inventive step, are within the scope of protection of the present invention.

Claims

1. A secondary stamping forming process based on ultrasonic vibration assistance comprises the following two steps: the first step forms a part blank through a stamping forming process, and the second step carries out secondary forming on the stamped part by applying ultrasonic vibration, so that the part precision is improved, and stress concentration is eliminated.

2. The ultrasonic vibration assisted secondary stamping forming process as claimed in claim 1, wherein the stamping process of the first step can adopt hydraulic stamping equipment or electric servo motor stamping equipment.

3. The ultrasonic vibration assisted secondary stamping forming process is characterized in that a workpiece to be machined can be stamped in two steps on the same equipment and can be clamped for the second time, but a positioning structure needs to be designed in the part during the secondary clamping, so that the clamping precision is guaranteed.

4. The ultrasonic vibration assisted secondary stamping forming process is characterized in that the machinable material is an elastic plastic metal material, and the shape is not limited.

5. The secondary stamping forming process based on the ultrasonic vibration assistance as claimed in claim 1, wherein the application of the auxiliary ultrasonic vibration is beneficial to reducing the deformation resistance of the metal material, reducing the interface friction force between the workpiece and the die and improving the surface quality of the formed metal material.

6. The ultrasonic vibration assisted secondary stamping forming process according to claim 1, wherein the surface precision of the machined part is improved compared with that of a single stamping, the internal stress is eliminated, and the aging rebound of the part is reduced.

7. The structure of the amplitude transformer (3) is designed into a step-type amplitude transformer (3) made of steel, and the working frequency range of the ultrasonic vibration-assisted forming processing is 20-30 KHz.

8. The structure design of the amplitude transformer of claim 7, the amplitude transformer (3) is in a 10 th order mode, the amplitude transformer (3) expands and contracts along the axial direction, the amplification factor of the amplitude transformer (3) is more than 2, and when the amplitude of the input end is more than 5 μm, the amplitude of the output end can reach at least more than 10 μm.

9. The structural design of the amplitude transformer of claim 7, the size of the amplitude transformer (3) satisfies L2+ L3+ t ═ λ/2.