阅读说明：本技术 一种采用电弧增材与激光增材复合的复杂金属零件成形方法 (Method for forming complex metal part by adopting electric arc additive and laser additive compounding ) 是由 薛飞 崔鑫 方学伟 彭娜 宋春男 于 2020-04-21 设计创作，主要内容包括：本发明公开了一种采用电弧增材与激光增材复合的复杂金属零件成形方法,包括对零件实体进行三维建模,对三维实体模型进行几何特征分解,零件特征增材成形方法划分,确定各特征成形工艺参数,对各特征成形排序,针对各特征进行切片分层处理,根据特征成形排序及相邻特征间结合界面的处理方法,将各特征依次成形。本发明有效结合了电弧增材制造成形高效以及激光增材制造成形精细的优点,相比于传统锻造缩短了加工周期,既保证了零件整体的成形性,又保证了精细、复杂结构的质量,提高了生产效率,降低了加工成本。同时采用激光重熔的方法,减少了异种增材工艺结合界面区域的裂纹和气孔数量,同时也使组织分布更加均匀,提高了结合界面的力学性能。(The invention discloses a complex metal part forming method adopting electric arc additive and laser additive compounding, which comprises the steps of carrying out three-dimensional modeling on a part entity, carrying out geometric characteristic decomposition on a three-dimensional entity model, dividing a part characteristic additive forming method, determining each characteristic forming process parameter, sequencing each characteristic forming, carrying out slicing and layering processing on each characteristic, and sequentially forming each characteristic according to the characteristic forming sequencing and a processing method of a combined interface between adjacent characteristics. The invention effectively combines the advantages of high efficiency of electric arc additive manufacturing and forming and fine laser additive manufacturing and forming, shortens the processing period compared with the traditional forging, ensures the forming property of the whole part, ensures the quality of a fine and complex structure, improves the production efficiency and reduces the processing cost. Meanwhile, the laser remelting method is adopted, so that the number of cracks and air holes in the combined interface area of the dissimilar material increase process is reduced, the tissue distribution is more uniform, and the mechanical property of the combined interface is improved.)

1. A method for forming a complex metal part by adopting electric arc additive and laser additive compounding is characterized by comprising the following steps:

step one, three-dimensional modeling is carried out on a part entity, allowance required by subsequent cutting machining is added outwards in the normal direction of the surface of the part entity, a three-dimensional entity model of an additive forming blank is generated, and geometric characteristic decomposition is carried out on the three-dimensional entity model;

analyzing the geometric features obtained by decomposition one by one, selecting the stacking direction of the features, extracting the nominal size of each feature, and judging whether the feature is suitable for electric arc additive forming or not according to the nominal size of the feature;

if the characteristics are not suitable for adopting electric arc additive forming, directly dividing the characteristics into B-type characteristics; if the characteristics are suitable for adopting electric arc additive forming, respectively estimating the time and cost for adopting electric arc additive forming and laser additive forming, and accordingly dividing the characteristics into A-type characteristics or B-type characteristics, wherein the A-type characteristics adopt electric arc additive forming, and the B-type characteristics adopt laser additive forming;

step three, forming and sequencing the geometric features obtained by decomposition, slicing and layering according to the additive forming method determined by each geometric feature, and determining forming process parameters selected by each geometric feature;

step four, in the adjacent feature forming process, processing the bonding interface after the former feature is formed, and determining the bonding interface processing method according to the additive forming method of the front and rear features and the surface roughness after the former feature is formed, wherein the method specifically comprises the following steps:

firstly, when the additive forming methods of adjacent features are the same, if the surface roughness is less than or equal to a defined value, directly forming the next feature; if the surface roughness is larger than the defined value, firstly, carrying out material reduction processing on the bonding interface to ensure that the surface roughness is smaller than or equal to the defined value, and then, continuously forming the latter characteristic; secondly, when the additive method of adjacent features is different, if the surface roughness is less than or equal to a defined value, directly carrying out laser remelting on the bonding interface, and continuously forming the next feature; if the surface roughness is larger than the defined value, firstly, reducing the material of the bonding interface to ensure that the surface roughness is smaller than or equal to the defined value, then, carrying out laser remelting on the bonding interface, and then, continuously forming the latter characteristic;

and fifthly, sequentially forming each feature according to the feature forming sequencing and the processing method of the bonding interface between the adjacent features, and performing material reduction processing on the surface of the part until the material increase process is completed completely, so that the precision of the size and the shape of the part can meet the design requirements.

2. The method of claim 1, wherein the nominal feature dimensions of step two comprise: the maximum length of the feature perpendicular to the direction of feature deposition is the nominal length l, and the minimum value of the wall thickness or width perpendicular to the direction of feature deposition is the nominal thickness d; the length of an arc starting unstable segment and an arc extinguishing unstable segment of the electric arc additive forming is a, the width of a single melting channel is f, if the nominal length l is shorter than the length a of the arc starting unstable segment and the arc extinguishing unstable segment, or the ratio of the nominal thickness d to the width f of the single melting channel is smaller, namely when l is less than or equal to alpha a or d is less than or equal to beta f, the characteristic is not suitable for the electric arc additive forming, the characteristic is considered as a B-type characteristic, wherein alpha and beta are proportionality coefficients, and the value range is as follows: alpha is less than or equal to 2, beta is less than or equal to 0.6.

3. The method for forming the complex metal part by adopting the arc additive and laser additive composite according to the claim 1, wherein the method for estimating the time and the cost of adopting the arc additive and the laser additive in the second step is as follows: when T is_{Electric arc}≤γT_LaserAnd P is_{Electric arc}≤P_LaserIf so, identifying the feature as a class A feature, otherwise, identifying the feature as a class B feature; wherein, T_{Electric arc}And T_LaserTime of arc additive and laser additive, P_{Electric arc}And P_LaserCosts for arc additive and laser additive, respectively;

gamma is a proportionality coefficient, is selected by combining the manufacturing requirements of parts, and has the value range as follows: gamma is less than or equal to 1 and less than or equal to 1.

4. The method for forming the complex metal part by adopting the arc additive and the laser additive composite as claimed in claim 1, wherein the laser remelting in the fourth step is to perform laser scanning melting on the formed or processed surface of the previous feature by adopting a laser cladding head under the condition of not sending materials and by adopting a set spot diameter and a set scanning speed; the laser power adopted by the laser remelting is 1 kW-2 kW, the laser spot diameter is 0.25 mm-3 mm, the scanning speed is 3 mm/s-30 mm/s, and the surface roughness defining value is less than or equal to Ra6.3.

5. The method for forming the complex metal part by adopting the arc additive and laser additive compounding as claimed in claim 4, wherein the scanning method adopted by the laser remelting comprises profile offset and sectional reciprocating scanning, the scanning track of the laser remelting covers the combination interface of the front and rear features, and the overlapping rate between the front and rear feature scanning tracks is controlled to be 5-40%.

6. The method for forming the complex metal part by adopting the arc additive and laser additive composite according to the claim 1, wherein the process types of the arc additive comprise: MIG, MAG, laser fuse, TIG, and PAW.

7. The method of claim 1, wherein the subtractive forming comprises turning, milling, and grinding depending on processing requirements of adjacent feature bonding interfaces.

Technical Field

The invention belongs to the field of metal additive manufacturing, and particularly relates to a method for forming a complex metal part by compounding electric arc additive and laser additive, which shortens the processing period, improves the processing quality and reduces the processing cost.

Background

At present, many parts with complex structures and high precision requirements exist in the aerospace field, such as casings of aero-engines. When a complex part is machined by a traditional machining method, a technological method of milling a forging blank is mainly adopted, the process is complex, the material utilization rate is low, the cutting allowance is large, and the machining time is often several months. The processing period of several months also obviously limits the productivity and the utilization rate of equipment, and becomes a bottleneck problem in the development and manufacture of part of complex products in the field of aerospace.

The additive manufacturing can realize near-net forming of the blank, the defect control of the additive manufacturing is superior to that of a casting blank, the material utilization rate is remarkably superior to that of a forging blank, and the application of the additive manufacturing has remarkable improvement effect on reducing machining allowance and shortening the research and development period of products.

The existing metal additive manufacturing method mainly comprises laser additive and electric arc additive, the laser additive has the advantages of high precision of formed parts, and the electric arc additive has the technical advantages of high forming efficiency, high wire material utilization rate and low material cost. However, both processes have their own disadvantages, which are critical to the efficiency of forming and the efficiency of powder utilization. The electric arc additive technology has the defects of low forming precision and high difficulty in controlling process stability.

By means of characteristic decomposition and process compounding, efficient forming is achieved by means of an electric arc additive process, fine forming is achieved by means of a laser additive process, and advantages of the two processes can be complemented. At present, the process composition of electric arc additive and laser additive is realized, and the difficulty is that the combination interface structure and the mechanical property are poor, so that the performance of a formed part is easily not up to the standard, and therefore, the optimization of the combination interface structure and the performance becomes the core problem of the process composition.

Disclosure of Invention

The invention aims to solve the problems of high precision and high efficiency processing of parts with complex structures in the prior art, and provides a method for forming a complex metal part by adopting arc additive and laser additive compounding, which effectively combines the advantages of two process modes of arc additive and laser additive, improves the structure and mechanical properties of a combined interface, shortens the production period and improves the material utilization rate.

In order to achieve the purpose, the invention adopts the following technical scheme:

a method for forming a complex metal part by adopting electric arc additive and laser additive compounding comprises the following steps:

step one, three-dimensional modeling is carried out on a part entity, allowance required by subsequent cutting machining is added outwards in the normal direction of the surface of the part entity, a three-dimensional entity model of an additive forming blank is generated, and geometric characteristic decomposition is carried out on the three-dimensional entity model;

analyzing the geometric features obtained by decomposition one by one, selecting the stacking direction of the features, extracting the nominal size of each feature, and judging whether the feature is suitable for electric arc additive forming or not according to the nominal size of the feature;

if the characteristics are not suitable for adopting electric arc additive forming, directly dividing the characteristics into B-type characteristics; if the characteristics are suitable for adopting electric arc additive forming, respectively estimating the time and cost for adopting electric arc additive forming and laser additive forming, and accordingly dividing the characteristics into A-type characteristics or B-type characteristics, wherein the A-type characteristics adopt electric arc additive forming, and the B-type characteristics adopt laser additive forming;

step three, forming and sequencing the geometric features obtained by decomposition, slicing and layering according to the additive forming method determined by each geometric feature, and determining forming process parameters selected by each geometric feature;

step four, in the adjacent feature forming process, processing the bonding interface after the former feature is formed, and determining the bonding interface processing method according to the additive forming method of the front and rear features and the surface roughness after the former feature is formed, wherein the method specifically comprises the following steps:

firstly, when the additive forming methods of adjacent features are the same, if the surface roughness is less than or equal to a defined value, directly forming the next feature; if the surface roughness is larger than the defined value, firstly, carrying out material reduction processing on the bonding interface to ensure that the surface roughness is smaller than or equal to the defined value, and then, continuously forming the latter characteristic; secondly, when the additive method of adjacent features is different, if the surface roughness is less than or equal to a defined value, directly carrying out laser remelting on the bonding interface, and continuously forming the next feature; if the surface roughness is larger than the defined value, firstly, reducing the material of the bonding interface to ensure that the surface roughness is smaller than or equal to the defined value, then, carrying out laser remelting on the bonding interface, and then, continuously forming the latter characteristic;

and fifthly, sequentially forming each feature according to the feature forming sequencing and the processing method of the bonding interface between the adjacent features, and performing material reduction processing on the surface of the part until the material increase process is completed completely, so that the precision of the size and the shape of the part can meet the design requirements.

The nominal feature size in step two comprises: the maximum length of the feature perpendicular to the direction of feature deposition is the nominal length l, and the minimum value of the wall thickness or width perpendicular to the direction of feature deposition is the nominal thickness d; the length of an arc starting unstable segment and an arc extinguishing unstable segment of the electric arc additive forming is a, the width of a single melting channel is f, if the nominal length l is shorter than the length a of the arc starting unstable segment and the arc extinguishing unstable segment, or the ratio of the nominal thickness d to the width f of the single melting channel is smaller, namely when l is less than or equal to alpha a or d is less than or equal to beta f, the characteristic is not suitable for the electric arc additive forming, the characteristic is considered as a B-type characteristic, wherein alpha and beta are proportionality coefficients, and the value range is as follows: alpha is less than or equal to 2, beta is less than or equal to 0.6.

Step two, the method for estimating the time and the cost of adopting the electric arc additive manufacturing and the laser additive manufacturing is as follows: when T is_{Electric arc}≤γT_LaserAnd P is_{Electric arc}≤P_LaserIf so, identifying the feature as a class A feature, otherwise, identifying the feature as a class B feature; wherein, T_{Electric arc}And T_LaserTime of arc additive and laser additive, P_{Electric arc}And P_LaserCosts for arc additive and laser additive, respectively;

gamma is a proportionality coefficient, is selected by combining the manufacturing requirements of parts, and has the value range as follows: gamma is less than or equal to 1 and less than or equal to 1.

The laser remelting refers to performing laser scanning melting on the former feature forming or processing surface by adopting a laser cladding head with a set spot diameter and a set scanning speed under the condition of not sending materials; the laser power adopted by the laser remelting is 1 kW-2 kW, the laser spot diameter is 0.25 mm-3 mm, the scanning speed is 3 mm/s-30 mm/s, and the surface roughness defining value is less than or equal to Ra6.3.

The scanning method adopted by the laser remelting comprises profile offset and partition reciprocating scanning, the scanning track of the laser remelting covers the combination interface of the front and the rear features, and the overlapping rate between the front and the rear feature scanning tracks is controlled to be 5-40%.

The process types of the arc additive include: MIG, MAG, laser fuse, TIG, and PAW.

The processing requirements of the adjacent feature combination interface include turning, milling and grinding.

Compared with the prior art, the invention has the following beneficial effects:

compared with the traditional processing mode, the additive manufacturing method can realize the die-free near-net forming, the formed part has a complex shape, the mechanical property is higher than that of the part manufactured by the forging method, the production period is greatly shortened, and the material utilization rate is improved. According to the invention, electric arc additive and laser additive are combined, the A-class characteristics with simple structure and larger size in the part are formed by electric arc additive, and the B-class characteristics with complex structure and fine structure are finished by laser additive. Compared with a single material increase method, the method disclosed by the invention combines the advantages of the two methods, not only ensures the integral formability of the part, but also ensures the quality of a fine and complex structure, greatly improves the production efficiency and reduces the processing cost. Meanwhile, the laser remelting method is adopted, so that the number of cracks and air holes in a combined interface area of the dissimilar additive process is reduced, the tissue distribution is more uniform, and the mechanical property of the combined interface is improved.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.

Fig. 1 is a flow chart of a process method based on arc additive and laser additive composite;

FIG. 2 is a flow chart of a feature additive method decision;

FIG. 3 is a flowchart of a method for processing an inter-feature binding interface;

FIG. 4 is a schematic illustration of the principle of laser remelting;

FIG. 5 is a schematic drawing of parts of an embodiment of the present invention;

FIG. 6 is a cross-sectional view of a part of an embodiment of the present invention;

FIG. 7 is an exploded view of a feature of an embodiment of the present invention;

FIG. 8 is a schematic view of a characteristic of an arc additive forming constant diameter revolution a;

fig. 9 is a schematic view of a laser additive formed partially convex feature.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, not all, embodiments of the present invention.

Based on the embodiments of the present invention, those skilled in the art can make several simple modifications and decorations without creative efforts, and all other embodiments obtained belong to the protection scope of the present invention.