RU2750603C1 - Apparatus for production of parts using additive-subtractive-hardening technology - Google Patents

Abstract

FIELD: additive manufacturing technology.SUBSTANCE: invention relates to an apparatus for growing a part by means of additive-subtractive-hardening technology and can be used in various fields of mechanical and aircraft engineering, as well as the rocket and space industry. The additive module of the apparatus using subtractive transitions for mechanical treatment of basic connecting surfaces between the transitions of growing parts of a detail of a complex shape, access whereto after the synthesis of the entire part is hindered or impossible, has two or more surfacing units and two sources of concentrated energy flow, respectively. Each surfacing unit supplies similar or different metal material to the growing area. To ensure stability of the growing process, an oscillator is used allowing to ignite an electric arc without contacting the surface of the detail and to maintain combustion required for surfacing layers of the metal material. The additive module has an automated control system for supplying metal wire in three coordinates for each surfacing unit.EFFECT: technical result consists in expanding the technological capabilities of the additive-subtractive-hardening technology, increasing growing productivity and improving the quality of the grown metal.4 cl, 5 dwg

Description

The invention relates to the production of products by additive technologies and can be used in various fields of machine and aircraft construction, as well as the rocket and space industry.

One of the most promising directions in the development of additive technologies is the possibility of producing finished parts or semi-finished products from metallic materials. When growing metal parts, it is necessary to ensure high accuracy of the product, high-quality structure of the material, absence of pores, as well as high productivity and low cost.

The problem of increasing the accuracy of shaping and obtaining the required dimensions during growth can be solved by using mechanical processing of synthesized surfaces - subtractive processing. The most effective solution is not mechanical processing of the finished part, but the possibility of mechanical processing in the process of additive growth, between the transitions of layer-by-layer synthesis. This makes it possible to provide machining with high accuracy of hard-to-reach surfaces, access to which is impossible or problematic when processing a finished part. The problem of improving the structure and mechanical characteristics of the grown metal can be solved by using hardening treatment in the process of additive growth.

The known method and device for layer-by-layer synthesis of metal products from metal-powder compositions by laser sintering, when after the formation of several sintered layers, they are machined with a cutting tool, and immediately on the site, after passing the cutting tool, laser heat treatment is carried out, increasing the hardness and density of the grown metal [ US 6657155 (B2). Method of and apparatus for making a three-dimensional object. 2003]. The device includes a unit for forming a powder layer, a unit for forming a sintered layer by irradiating a specified part of a powder layer with an optical beam, a distance regulator for adjusting the distance between the unit for forming a sintered layer and a sintered layer and a unit for removing a surface layer with a density lower than that of the sintered layer.

The disadvantages of this method and device are low productivity, which is significantly inferior to surfacing methods, low efficiency, high cost of equipment and used powder materials, as well as insufficient technological capabilities for growing materials with different properties.

The problem of increasing productivity can be solved by using the method of layer-by-layer surfacing of the material for growing metal parts, where the model material is a metal bar or wire. Unlike the laser sintering process, layer-by-layer surfacing provides a traditional cast metal structure in the product. The cost of the used metal rod or wire is 9-10 times lower than the cost of powder materials for additive technologies.

The problem of increasing the technological capabilities for the creation of grown materials combining various properties, as well as productivity, can be solved by a device in which several nodes for surfacing are used. A device is known by means of which the synthesis process is carried out simultaneously by several nodes for surfacing, supplying powder or wire, including powder and wire, to the zone of additive forming simultaneously [US 2019111509 (A1). Wire arc hybrid manufacturing. 2019]. This helps to expand the technological capabilities of the process, but does not ensure the formation of a dense defect-free structure of the material. The structure of the synthesized metal has a large number of defects (pores, coarse grains), which contributes to a decrease in strength characteristics and does not meet high requirements for the quality of the material.

The problem of improving the structure and mechanical characteristics of the grown metal by layer-by-layer surfacing can be solved by using deformation-hardening treatment in the process of layer-by-layer synthesis. A known method and device for the manufacture of products from successive layers of metal, fusing on each other with plasma or arc energy, when each subsequent deposited layer is subjected to plastic deformation by a plunger device, crushing and optimizing the grain size of the deposited metal and thereby improving the mechanical properties of the material of the product [US 20070122560 (A1). Solid-free-form fabrication process including in-process component deformation. 2007].

The device contains a platform on which the growth is carried out, a device for supplying the source material to a predetermined area for the formation of successive metal layers, a plasma or arc energy source directed to a predetermined area, a pneumatic or electromagnetic plunger device for plastic deformation of the deposited metal layer.

The disadvantages of this method and device are low dimensional accuracy, which requires the provision of large allowances for subsequent machining, the impossibility of processing hard-to-reach surfaces, which limits the scope of this method, limitations on productivity, depth and degree of hardening of the deposited layer, density and reduction in grain size.

Known device for additive-subtractive-hardening technology, which carries out layer-by-layer synthesis of products, including the growth by layer-by-layer surfacing of material from wire with periodic plastic deformation of the grown layer by static-pulse processing with a deformation wave and its subsequent mechanical subtractive processing [Possibilities of additive-subtractive-hardening technology / Kirichek A.V., Soloviev D.L., Zhirkov A.A., Fedonin O.N., Fedonina CO, Khandozhko A.V. // Bulletin of the Bryansk State Technical University. 2016. No. 4 (52). S. 151-160]. The device contains an additive module responsible for the growth of a part, a subtractive module that ensures the accuracy of dimensions and the relative position of critical surfaces due to the removal of chips, and a hardening module that allows structuring, compaction, hardening and stress relief in the grown layer due to the wave deformation effect.

Static-pulse treatment with a deformation wave carries out the formation of a hardened structure of the material under the action of shock waves, as a result of which a set of plastic imprints with a certain size, overlap and multiplicity of application is formed on the hardened surface [Kirichek AV, Soloviev DL, Lazutkin A. G. Technology and equipment for static-impulse treatment by surface plastic deformation. Technologist's library. M .: Mashinostroenie, 2004. 288 p.]. When using static-impulse processing, the metal structure is refined and a hardened work-hardened surface layer with a depth of 0.1-0.3 mm to 8-10 mm, with a hardness reaching 35-45 HRC, and compressive residual stresses can be obtained. a dense, both uniformly and heterogeneously hardened structure was obtained.

The use of the device for the implementation of the additive-subtractive-hardening technology makes it possible to create a heterogeneously hardened structure in the grown product, form compressive residual stresses, increase the productivity of the process, and increase the dimensional accuracy of the grown product. In the hardened material obtained in this way, in contrast to the unhardened material, there are practically no pores and hidden cavities. The dimensions of the phase elements in the material obtained by technology with hardening are more than five times smaller than the material obtained without hardening. The microhardness of the material grown with hardening is two times higher than the microhardness of the material obtained without hardening.

The disadvantages of such a device are the impossibility of growing a part simultaneously from several different metallic materials, as well as the instability of the growing process, which leads to a decrease in the quality and uniformity of the grown metal.

The aim of the proposed invention is to expand the technological capabilities of the additive-subtractive-hardening technology (ACS), increase the productivity of growing and the quality of the grown metal from various metallic materials. Under the various metal material used in the proposed device for creating parts by additive-subtractive-hardening technology, it is understood a metal wire for surfacing of various diameters and from various metals.

The goal is achieved by the fact that in a device for the implementation of the additive-subtractive-hardening technology, using subtractive transitions for machining the base connecting surfaces between the transitions for growing parts of a part of a complex shape, access to which after the synthesis of the entire part is difficult or impossible, and the wave deformation effect for hardening , the additive module responsible for growing the part has two or more surfacing units, each of which has its own source of concentrated energy flow, while each surfacing unit supplies the same or different metal material to the growing zone using its own wire feed unit, and to ensure the stability of the growing process, an oscillator is used in each surfacing unit, which allows you to ignite an electric arc without contact with the surface of the part and maintain the combustion required for surfacing layers of metal material, in addition, the additive module has an a tomatized three-axis feed control system for each surfacing unit, using feedback on the gap between the end of the wire being welded and the surface of the part being grown. Further, in the description of the present invention, we will restrict ourselves to the case when the additive module uses two nodes for surfacing. The proposed device with a large number of nodes for surfacing works in a similar way and leads to a further expansion of the technological capabilities of the additive-subtractive-hardening technology, which are noted above.

To increase the productivity of growing metal products, it is advisable to grow using different wire diameters in different nodes for surfacing. To obtain the main dimensions of the product, a wire with a diameter of 3-5 mm is used, and to provide complex figured surfaces, a wire with a diameter of 0.8 mm and below. To obtain bimetallic products, each of the surfacing units supplies a metal material from a different metal to the growing zone.

The subtractive module allows, after growing a certain part of a part of a complex shape and hardening by static-pulse processing with a deformation wave (one or more) of the deposited layers using a hardening module, to perform mechanical cutting, ensuring the accuracy of the dimensions and relative position of critical (connecting) surfaces, access to which after growing the entire part is difficult or impossible.

The device for the automated control system contains (Fig. 1):

1 - additive module;

2 - wire feed unit;

3 - subtractive module;

4 - rotary table;

5 - hardening module;

6 - pulse generator;

7 - one unit for surfacing;

8 - node for surfacing two;

9 - cutting tool of the subtractive module (cutter).

FIG. 2 illustrates the ACS process itself, where the positions indicate:

10 - deposited metal layer;

11 - part to be grown;

12 - striker;

13 - waveguide;

14 - deforming tool;

15 - hardened deposited metal layer;

16, 17 - sources of concentrated energy flow for surfacing units one and two, respectively;

17 - source of concentrated energy flow for surfacing unit two. Also in FIG. 2 introduced the notation:

А ₁ and А ₂ - fluctuations (conditionally) of the corresponding sources of concentrated energy flux of nodes for surfacing;

P _and - energy of shock waves of deformation;

ƒ is the frequency of blows;

P _st - preliminary static compression of the waveguide;

S is the direction of feeding: the source of the concentrated energy flux relative to the workpiece in FIG. 2a, the deforming tool in FIG. 2b, the cutting tool of the subtractive module (cutter) in FIG. 2c (it is the same everywhere);

n is the rotation frequency of the cutting tool of the subtractive module (cutter).

The operation of the device occurs during the implementation of the following stages (Fig. 2):

a - layer-by-layer surfacing of the material (one or more layers) using an additive module;

b - hardening by static-pulse processing by a deformation wave (one or several) of the deposited layers, and in order to increase the efficiency of hardening, depending on the grade, properties and chemical composition of the material, the metal is deformed at a temperature of more than 100 ° C, but below the recrystallization temperature, this the stage is carried out with the help of a hardening module, and the hardening module makes it possible, due to the wave deformation effect, to structure, compact, harden and relieve stresses in the grown layer;

c - mechanical treatment of the deposited and, if necessary, hardened surface, in order to remove the defective layer and ensure high accuracy and low roughness of critical surfaces using a subtractive module.

The device for creating parts by additive-subtractive-hardening technology works as follows.

A metal base is installed on the turntable 4 (Fig. 1), on which the part 11 will be grown. Additive module 1 is switched on with included wire feed units 2, a surfacing unit 7 and a surfacing unit two 8. With the help of feed drives along three coordinates, the sources of the concentrated energy flux 16 and 17 are brought to the metal base, which is installed on the rotary table 4, and with the help of the oscillator of the involved surfacing unit, an electric arc is ignited without contact with the surface of the metal base. The movements of the sources of the concentrated energy flow 16 and 17 are carried out by an automated control system for the feed drives in three coordinates using the control program of the numerical program control of the device. The material is deposited in one or several layers, depending on the geometry, properties of the deposited metal and the requirements for its quality characteristics. During surfacing, oscillators of surfacing units operate continuously, imparting oscillations to the sources of concentrated energy flux 16 and 17, respectively, A ₁ and A ₂ , as well as an automated feed control system along three coordinates with feedback on the gap between the end of the wire being deposited and the surface of the grown part 11 , which makes it possible to maintain the combustion required for the deposition of layers of metal material and to ensure the stability of the growing process.

The process of growing a part by laser, electron-beam, plasma or electric-arc layer-by-layer surfacing of a material from a wire, compared to powder additive technologies, is economically many times more profitable and provides higher productivity. The disadvantages of this technology in the form of structural defects, high porosity and lower accuracy are compensated for by hardening and mechanical treatment in the process of obtaining the part.

After surfacing one or several layers of metal material, in accordance with the control program, the hardening module 5 is switched on with the pulse generator 6 included in it, the main elements of which are the striker 12 and the waveguide 13. The pulse generator is supplied by feed drives along the three coordinates of the hardening module 5 to the deposited metal layer 10 and is pressed against it by the waveguide 13 through the deforming tool 14 with a force P _st . During hardening, the striker 12 strikes the waveguide 13 statically compressed to the deposited metal layer 10 through the deforming tool 14, as a result, plane acoustic waves are generated in the striker-waveguide shock system, which are characterized by the law of force variation (deformation wave amplitude) in time, the maximum value of the forces, the time of action of the forces (duration of the deformation wave) and the energy of the deformation wave. These characteristics depend on the geometry of the colliding striker 12 and waveguide 13, the properties of their materials and the speed of collision. The deformation wave consists of a sequence of pulses, the duration of each of which is equal to the period of the wave. The shape of the shock pulse (change in force over time) entering the deformation zone will determine the efficiency of dynamic loading. The shape of the shock pulse entering the deformation zone and the contact area of the deforming tool 14 with the deposited metal layer 10 will determine the efficiency of dynamic loading. Preliminary static compression of the waveguide 13 contributes to the most complete use of the pulse load for plastic deformation of the deposited metal layer 10. During hardening, the shape of the shock pulses is maximally adapted to the properties of the material and loading conditions, which increases the efficiency of the hardening process, expands the technological capabilities of processing the deposited metal layer 10.

The hardening module, which implements the technology of hardening by static-impulse treatment, makes it possible to structure, compact, harden the material of the grown layer, and form, instead of tensile residual stresses of a thermal nature, compressive ones. Strengthening extends to a depth greater than the deposited layer, which allows the use of static-impulse processing by a deformation wave not layer by layer, i.e. after surfacing of one layer of metal, and after surfacing of several layers, which contributes to an increase in the productivity of the process. When using wave strain hardening, it becomes possible to create a heterogeneously hardened structure of the grown metal material, which combines both hard and plastic regions, which is highly efficient in operation under conditions of fatigue loads.

After hardening processing, in accordance with the control program, the subtractive module 3 is switched on, the working body of which is the spindle head with the cutting tool of the subtractive module (cutter) 9. The cutter 9 of the subtractive module 3 is brought to the hardened deposited metal layer and produces, in accordance with the control program , processing by cutting its side surfaces, removing defective layers and sagging, as well as providing high accuracy and low roughness of critical surfaces.

Then the cycle is repeated in accordance with the requirements for the grown part.

Below are examples of typical parts that are advisable to be manufactured using the proposed additive-subtractive-hardening technology. It is shown, due to which, the manufacturing efficiency will increase in the case of using the proposed device.

Example 1. Growing an extended monometallic large-sized part, such as "Nervura" or "Honeycomb panel" [6] (Fig. 3) simultaneously from two sides by two nodes for surfacing and, accordingly, two sources of concentrated energy flow, working with a wire of the same diameter, which allows you to increase the productivity of growing up to 2 times.

Example 2. Growing a monometallic large-sized part with elements significantly different in thickness: massive load-bearing elements of the body and thin ribs, thin-walled hollow bosses, a part of the "Shaft neck" type [7] (Fig. 4). When growing such parts with one node, small-diameter wire should be chosen for surfacing, since the minimum possible wall thickness of the component's structural element is always slightly greater than the thickness used for growing the wire. At the same time, the productivity of growing massive thick-walled elements directly depends on the diameter of the wire: with an increase in the diameter of the wire, productivity increases. In order to expand the technological capabilities of the proposed device and increase the productivity of growing, it is advisable to use two nodes for surfacing and, accordingly, two sources of concentrated energy flux, one of which works with a wire of large diameter and is intended for growing massive thick-walled elements, and the second is of small diameter and is intended for growing thin-walled elements.

Example 3. Growing a bimetallic large-sized part of the "Bimetallic sleeve" type (Fig. 5) with two nodes for surfacing and, accordingly, two sources of concentrated energy flux, working with wires of the same or different diameters from different materials. When growing bimetallic parts, surfacing of a material with a low melting point on a material with a high melting point, as a rule, presents no technological difficulties.

At the same time, with a significant difference in the melting temperatures of the materials being deposited, a serious difficulty is the surfacing of a material with a higher melting point (outer shell) on a material with a low melting point (inner shell). When a reliable bimetallic joint is formed at the ends of thin structural elements (ribs), due to melting, deviations in shape and size occur, and the geometric accuracy of the part is violated. This significantly limits the technological capabilities of the method and device, requires the application of additional intermediate layers of materials of a special composition, which, in turn, significantly reduces the productivity of growing the part.

When using the proposed device, the problem is solved by layer-by-layer growing of a bimetallic part by two sources of concentrated energy flow, working with wires of the same or different diameters from different materials. In the formation of each layer, a material with a high melting point (for example, a layer of an outer shell) is first deposited, and then a material with a low melting point (for example, a layer of an inner shell).

The technical effect of using two sources of concentrated energy flow in the device is to expand the technological capabilities of the device and increase the productivity of growing.

Sources of information taken into account

1. US 6657155 (B2). Method of and apparatus for making a threedimensional object. 2003

2.US 2019111509 (A1). Wire arc hybrid manufacturing. 2019

3. US 20070122560 (A1). Solid-free-form fabrication process including in-process component deformation. 2007

4. Possibilities of additive-subtractive-hardening technology / Kirichek A.V., Soloviev D.L., Zhirkov A.A., Fedonin ON, Fedonina C.O., Khandozhko A.V. // Bulletin of the Bryansk State Technical University. 2016. No. 4 (52). S. 151-160

5. Kirichek A.V., Soloviev D.L., Lazutkin A.G. Technology and equipment for static-impulse treatment by surface plastic deformation. Technologist's library. M .: Mashinostroenie, 2004.288 p.

6.https: //3dtoday.ru/blogs/news3dtoday/large-3d-printing-metals-technology-eubam-company-sciaky/

7.https://3dtoday.ru/blogs/news3dtoday/provoloka-dlya-additivnykh-tekhnologiy-innovatsii-i-traditsii-v-odnom-produkte/

Claims (4)

1. A device for manufacturing a part by means of additive-subtractive-hardening technology, containing an additive module for growing a part by surfacing a metal wire, a hardening module made with the ability to structure, densify, harden and relieve stresses in the grown layer by means of a wave deformation effect, and a subtractive module for mechanical processing by cutting, made with the possibility of ensuring the accuracy of the dimensions and the relative position of the critical surfaces of the part, characterized in that the additive module for growing the part contains at least two nodes for surfacing, each of which is made with the possibility of automated control of the metal wire feed along three coordinates, while the additive module, the hardening module and the subtractive module are made with the possibility of layer-by-layer processing of the grown part. 2. The device according to claim 1, characterized in that each of the nodes for surfacing the additive module is configured to feed a metal wire of various diameters into the growing zone. 3. The device according to claim 1 or 2, characterized in that each of the nodes for surfacing the additive module is made with the possibility of feeding a part of a metal wire from a different metal into the growing zone. 4. Device according to any one of paragraphs. 1-3, characterized in that each node for surfacing the additive module contains an oscillator.

Images