SU1692789A1 - Method for ultrasonic welding - Google Patents

Abstract

The invention can be applied in the production of current sources and improves the efficiency of the welding process and improves the quality of the welded joint. Ultrasonic vibrations are transmitted through the protrusion of the tip to the upper part by pressing it into the part until it moves together with the tip. After the formation of a rigid connection, the tip-part additionally focuses the ultrasonic energy throughout the entire welding time. The focusing depth F of the ultrasonic energy is determined from the expression F R / (1 - -Message / Sac.), Where R is the radius of curvature of the tip; Go away, Snacon. The speed of ultrasound in the material parts and tip. The welding device comprises a tip waveguide with a protrusion and a movable base. The protrusion of the tip has a concave shape, and the base is a protrusion of a convex shape coaxially with the tip protrusion. Dimensions and materials of the tip and base must meet the requirements of the Icon. It will come down Sosnov .. pSnakon / s It comes P Sosnov., S, where p is the density of the material of the tool of the parts and the base being welded; S is the area of the protrusion; I - the wavelength of ultrasonic vibrations; 6 - part thickness. 1 ill., 1 tab.

Description

The invention relates to welding, in particular to a method for ultrasonic welding, and may find application in the manufacture of current sources.

The purpose of the invention is to increase the efficiency of the welding process and improve the quality of the welded joint.

The drawing shows the scheme of implementation of the method, the relative position of the welded parts.

The method is carried out as follows.

The parts to be welded 1, 2 are placed on the base 3 with a protrusion 4, the welding is performed by a waveguide in the form of a tip 5 s.

the protrusion 6. The latter has a concave shape, and the working surface of the base 3 has a protrusion 4 of convex shape of the same curvature, located coaxially with the protrusion of the tip; the dimensions and materials of the tip and the base should satisfy the conditions

Snacon Sv.det. Sosnov.,

R Snacon. / Essedet Sosnov.,

S,

where p is the density of the tool material, the parts to be welded and the base,

C t is the propagation velocity of ultrasound in the base material, the parts to be welded and the tip;

- S is the area of the working part of the protrusion; A is the wavelength of ultrasonic vibrations: d is the thickness of the parts to be welded. To localize the ultrasonic energy in the welding zone, it is necessary to have a minimum reflection from the surface of the welded parts and a maximum from the base surface. To do this, the condition must be met.

tips

 Sv.det. WITH

In order to localize the input ultrasound energy with a minimum of reflection from the surface of the metal being welded and a maximum of reflection from the base, it is necessary, after observing the first condition, to consider the relationship between the wave impedances of each element of the oscillatory system

ps

tips

ps

ev children

ps

the basics

With a big difference Snacon. And Ssv.det.

the density of the material to be welded must be greater than the density of the material of the tip, then the wave resistances of the tip - the part will be comparable. The wave impedance of the base must be less than the wave impedance of the material of the parts being welded.

In order to optimize the focusing condition of the ultrasound energy, it is necessary that when the inner concave surface of the tip comes in contact with the surface of the part to be welded, the tip area S is chosen in proportion to the product of the thickness b of the materials to be welded and the ultrasonic wavelength

 BUT.

During the welding process, the tip 5 goes deeper into the upper part 1 to a depth of the concave surface, and as it goes deeper, the amount of additional focused energy increases, which reaches a maximum with full contact of the concave surface of the tip with the surface of the part. At the same time, the tip is tightly connected to the part, acoustic contact is achieved and transmits not only the compressive force P, but also its vibrations, as a result of which the connected parts are heated at the point of contact. Thus, the formation of the joint occurs as a result of the compression, ultrasonic vibrations of the part in the contact zone and the focusing of the ultrasound energy into the joint zone. The additional focusing of the ultrasound energy made it possible to reduce the amount of power applied to the parts being welded, improve the structure of the metal, the seam, reduce the welding time and thereby improve the quality of the joints.

Focusing ultrasound energy in the joint zone contributes to improving the quality of the joint, since the metal in the joint zone experiences, in addition to compressive forces, additional axial oscillatory forces caused by the transmission conditions of ultrasonic vibrations in metals.

The focusing of ultrasound energy in the connection zone is carried out mainly after

inserting the tip into the welded part by the amount of deepening of the focusing surface, and the maximum amplitude of displacement of the upper welded part relative to the lower one is noted.

In the process of focusing involved

the vertical component of the motion of the waveguide, the tip of which moves in an arc, but in connection with the recess in the tip the surface of the welded

The metal in the imprint has a flat or convex appearance instead of a depression when using a flat tip.

The focusing of the ultrasound energy in the joint zone is carried out not only to achieve maximum energy density in the center of the joint zone, but also to obtain a uniform field in the weld print area, to stabilize the welding mode during tip wear, so

as with a flat tip, a change in the welding mode is observed as it is worn.

To verify the proposed resistivity method, the device parameters for resistivity models were calculated, and a prototype device was made based on the obtained values. Calculations of the parameters of the device were carried out for a specific task: welding of nickel sheets with a thickness of d of 0.12, 0.2 and

0.3 mm on the installation operating in the frequency range 20-40 kHz.

The materials of the tip and base are steel 45 and titanium, respectively. Operating frequency of the welding machine

22 kHz. The diameter of the welding tip for various thicknesses (e) of the parts is calculated from the expression 6 0.88, which is determined from the conditions of the optimal focusing of the ultrasonic energy in the joint zone.

welded parts, with the ratio of the intensity of focused oscillations (f) to the total intensity of oscillations (1 total)

  1 or common

i.o. ,four

, and

f 2.25 -n

total F 12 - l

n

where E is the Yugna module; F is the depth of focusing of the ultrasound energy.

Then, from the expression of the specific work of another deformation of the tip,

The magnitude of its penetration (-) into the upper

detail at load P (n is the multiplicity of the tip protrusion)

R

where a is the elastic limit of the material being welded; D is the diameter of the protrusion of the tip: p is the coefficient taking into account the type of loading.

The data obtained are tabulated. The strength of the welded joints obtained at the same time is not less than 0.85 Metal axis, and the required power of the welding unit is reduced by 20-25% compared to the use of flat tips.

The wear of flat and concave tips during the comparative analysis does not exceed 0.1 ± 0.02 mm. In all cases, there was a decrease in the value of the demand load by 10–15%.

Thus, the proposed method increases the efficiency of welding tips, increases their service life, improves the structure of the material to be welded, improves its quality, reduces the formation time of the weld point and increases the welding speed, and reduces the power of the installation without losing the quality of the welded joint.

Claims (1)

Invention Formula The method of ultrasonic welding, in which the elements to be welded are positioned on the base with a protrusion, is performed by transferring ultrasonic vibrations through the tip with a protrusion that is pressed into the part, characterized in that, in order to increase the efficiency of the welding process and the quality of the joint by focusing the ultrasonic energy on to a predetermined depth, the protrusion of the tip is made with a curved working surface - and the protrusion of the base is with a convex surface of the same curvature, and the tips are made with dimensions and from a mat compliant rials Snacon Sv.det. Sosnov.,  pcc pcc p Snacon. there is no / Cutting.  BUT, where p is the density of the tool material of the parts to be welded and the base; S is the area of the protrusion; And - the wavelength of ultrasonic vibrations; d - part thickness, mm; Sv.det., Snacon. - the speed of ultrasound in the material of the appropriately welded part and tip, and the depth of focusing F ultrasonic energy is determined from the ratio F-R / (1-Ccd tac. where R is the radius of curvature of the tip, mm.