RU2284887C1 - Method for forming relief on surface of products - Google Patents

Abstract

FIELD: technology for processing products by concentrated energy stream, in particular, method for forming relief on surface of objects by means of laser beam, possible use in any engineering branch, using products with micro-relief on surface.

SUBSTANCE: substrate is mounted on the side of formed relief at distance L≤10h, where L - distance between substrate and processed material; h - thickness of material being processed. After mounting of substrate, material being processed is heated up by laser radiation on the side, opposite to one, on which relief is formed. Heating is performed until melted material moves towards substrate. Substrate may be made of powder material. After finishing relief forming process, substrate may be removed.

EFFECT: expanded functional capabilities, provision of high productiveness.

3 cl

Description

The proposed solution relates to the processing of parts by a concentrated flow of energy, in particular a laser beam, and can be used in any technical field that uses products with a microrelief on the surface, in particular in the manufacture of electronic products.

There are various methods of forming on the surface of various products of elements and holes using laser radiation, in particular [1]. The essence of the known method lies in the fact that the space between the surface elements of a given configuration is conventionally divided into two zones - surface and deep. Then, the focused laser beam is directed onto the workpiece surface of the product and scanning along the workpiece surface is performed to obtain a given contour. To remove from the surface zone the space between the convex elements of the entire material, the scan is repeated several times.

There is also known a method of forming a relief on the surface of the product, including irradiating the surface of the product with laser radiation and heating to melt the material of the product [2]. In the known method, laser radiation is directed to that surface of the product on which the desired profile of the pattern element is formed. The surface treatment of the product is carried out by moving a concentrated stream of laser radiation, forming in a given location of the product melt zones of a given size and configuration.

When forming the relief by known methods [1] and [2], a repetition of the procedure for moving the concentrated laser radiation flux over the treated surface is required, which limits their productivity. In addition, the known methods can only be used to obtain a given configuration of the recesses on the surface of the products and are unacceptable for the formation of the protruding parts of the relief.

The task of creating the proposed method of forming a relief on the surface of products is to expand its technological capabilities while increasing productivity.

The problem is solved due to the fact that in the method of forming a relief on the surface of the product, including irradiating the surface of the product with laser radiation and heating to melt the material of the product, a substrate is installed on the side of the formed relief at a distance L≤10 h from the surface of the product, where h is the thickness of the processed products, irradiation is carried out from the side opposite to the one on which the relief is formed, and in the process of heating the workpiece, it is melted to the entire thickness and the molten material is moved ial towards the substrate.

The substrate may be made of powder material.

After completion of the relief formation process, the substrate can be removed.

When a workpiece is irradiated with laser radiation above the surface of the product from the side of irradiation, a plasma is formed in a mixture of vapor of the processed material and the surrounding gas (in particular air), which exerts external pressure on the molten material formed in the treatment zone. Provided that the workpiece is melted to its entire thickness, the molten material moves outward under this pressure relative to the surface opposite to the one onto which the laser radiation is directed, and at the end of the laser radiation, the molten material is pulled back by surface tension forces into the processing zone . However, if from the side opposite to the one on which the laser radiation is directed, at a distance L≤10 h in relation to the material being processed, a substrate is installed and the material to be treated with a concentrated energy flow until the entire volume of the molten material moves towards the substrate, the solidification process of the outwardly displaced material due to heat transfer to the substrate, it occurs faster than the process of drawing it into the treatment zone by surface tension forces. Thus, the material hardens in the form of protrusions forming a relief.

It was experimentally established that at L> 10 h, the process of heat transfer to the substrate is ineffective and it is not possible to obtain the desired effect even with a significant increase in the pulse energy.

The parameters of the relief obtained by the proposed method depend on the radiation parameters. In particular, the cross-sectional area of the protruding parts is determined by focusing, and the height is determined by the energy and duration of the laser pulse.

Depending on the need to solve a specific technical problem, the distance between the material to be processed and the substrate can be chosen in such a way that either the elements of the formed relief adhere to the substrate (i.e., in fact, the relief and substrate are welded to form, for example, a volume grating), or after the process is complete, the substrate can be removed.

The use of a substrate of powder material during the process of forming a relief allows to further expand the technological capabilities of the proposed method. This is because the elements of the formed relief solidify by penetrating into the powder material and interacting with it. The powder material is sorbed by the surface of the melt, giving the resulting relief physico-chemical properties due to the composition of the powder material.

The formation of one element of the relief can be carried out within one pulse, i.e. in General, the performance of the proposed method is determined by the pulse repetition rate of the laser radiation. The implementation of the proposed method by applying two pulses, similar to the implementation of the known method [2], is possible, but not required. Those. the performance of the proposed method in comparison with the known [2] above and is determined by the pulse repetition rate of the laser radiation.

In the case of applying the proposed method in the conditions of mass production, the process can be automated and regulated using a computer.

The proposed method was tested when forming a relief on a plate made of stainless steel 12X18H10T 30 mm long, 30 mm wide, 0.3 mm thick. The relief was formed by pulsed radiation from an AIG laser. The pulse duration was 5–10 ms, and the pulse energy was 5–9 J. The radiation was focused on the surface of the processed material using a focusing system with a focal length of 50 mm. A substrate was also used from steel 12X18H10T. The distance between the plate and the substrate ranged from 0.3 to 3 mm. Over the entire specified range of distances, a relief in the form of needles was obtained. With an increase in the indicated distance L over a value equal to 10 h, it was not possible to obtain a relief even with a significant increase in energy and pulse duration.

In addition, the proposed method was tested using the same equipment, materials and dimensions of the product, the material of which the relief was formed, and the substrate of a powder material consisting of a mixture of chromium with cobalt. The product, from the material of which the relief was formed, was placed on the surface of the powder material. The process was carried out under the same conditions. After removing the substrate from the powder material, a relief was also obtained in the form of needles formed from plate material doped with chromium and cobalt.

The proposed method can be used to obtain products for various purposes, for example:

a) field emission cathodes with desired properties due to the use of various powder materials;

b) filters with catalysts;

c) filters of complex configurations;

d) any lattice structures, in particular multilayer lattice

structures of various materials.

Information sources

1. Patent of the Russian Federation No. 2080971, the application. 06/01/1994, publ. 06/10/1997, IPC 6 V 23 K 26/00. "The method of laser engraving"

2. Application for invention No. 2003101785, the application. 01/22/2003, publ. 07.27.2004, IPC 7 V 23 K 26/18. "A method of forming a microrelief of the surface of products and a device for its implementation" - prototype.

Claims (3)

1. The method of forming a relief on the surface of the product, including irradiating the surface of the product with laser radiation and heating to melt the material of the product, characterized in that on the side of the formed relief, a substrate is installed at a distance L≤10h from the surface of the product, where h is the thickness of the processed product, irradiation from the opposite side to the one on which the relief is formed, and during the process of heating the workpiece, melt it to the entire thickness and move the molten material towards the substrate. 2. The method according to claim 1, characterized in that the substrate is made of powder material. 3. The method according to claim 1 or 2, characterized in that after the completion of the relief formation process, the substrate is removed.