阅读说明：本技术 Tig电弧増材成形时变参数定距自适应控制方法 (TIG electric arc additive forming time-varying parameter distance self-adaptive control method ) 是由 王鑫 任文举 王淑娴 刘飞 谭峰 李海青 冯松 于 2020-12-22 设计创作，主要内容包括：本发明请求保护一种TIG电弧増材成形时变参数定距自适应控制方法,属于TIG电弧増材与3D成形领域；该TIG电弧増材成形变宽度参数的零件时,将不等宽零件沿成形方向,将变宽度单元进行逐段离散化,细分成多条高度相等、具有一定宽度的单元体；通过多段可控层宽的组合来逼近不等宽的沉积层形貌,将多线条搭接组装为一次变截面成形,在适合的区间内通过计算修正成形速度与成形电流,从而实现沉积层宽度的闭环控制；所提出的定距自适应控制方法,可逐层连续成形出平整的结构单元,并简化了路径、降低了搭接次数与界面重熔次数,在保持零件其他方向尺寸不变的情况下,极大提高了TIG电弧増材成形零件的复杂度和成形效率。(The invention discloses a TIG electric arc additive forming time-varying parameter distance self-adaptive control method, belonging to the field of TIG electric arc additive and 3D forming; when the TIG electric arc additive forming part with the variable width parameter is used, the variable width part is discretized section by section along the forming direction, and is subdivided into a plurality of unit bodies with equal height and certain width; the shape of a deposition layer with unequal widths is approached by the combination of multiple sections of controllable layer widths, multiple lines are overlapped and assembled into one-time variable cross section forming, and the forming speed and the forming current are corrected by calculation in a proper interval, so that the closed-loop control of the width of the deposition layer is realized; the distance self-adaptive control method can continuously form flat structural units layer by layer, simplifies the path, reduces the times of lap joint and interface remelting, and greatly improves the complexity and the forming efficiency of the TIG electric arc additive forming part under the condition of keeping the sizes of the part in other directions unchanged.)

1. The TIG electric arc additive forming time-varying parameter distance self-adaptive control method is used for manufacturing multilayer single-channel width-varying thin-wall part structural parts, and the multilayer single-channel width-varying thin-wall part structural parts are printed and formed through an electric arc additive manufacturing system in a 3D mode, and is characterized by comprising the following steps of:

step 1: carrying out layered slicing on the CAD model of the built variable-width part to obtain data information of each layer of width;

step 2: the unequal-width unit discretizes the width data section by section along the forming direction, subdivides the unequal-width unit into a plurality of unit bodies with equal height and certain width, and the width of each section is i, i +1, i +2 … i + m;

and step 3: determining the height h and the width w of an expected layer of each section according to actual requirements;

and 4, step 4: the forming speed V and the forming current I are used as input quantities, and in the control process of each section, the forming speed V is_iAnd a shaping current I_iThe average width of each segment is w_i(ii) a According to feedback data of visually monitoring the height and the width of the layer in real time, realizing closed-loop control of the size of the settled layer through dynamic self-adaptive correction of forming current and forming speed;

and 5: and (4) repeating the steps 2 to 4 after finishing the forming path of one layer and descending the three-dimensional motion forming platform by the corresponding layer thickness, and continuously forming a next layer of smooth structural unit until the part is processed.

2. A TIG electric arc additive forming time-varying parameter distance self-adaptive control method according to claim 1, characterized in that the test platform is a self-built TIG wire feeding electric arc additive manufacturing device, the power supply system is a Fornes MW3000, the wire feeder is an argon arc welding automatic wire feeder WF-007A, the wire is a 7A09 aluminum alloy welding wire with a diameter of 1.2mm, the welding gun is fixed on the three-dimensional workbench and sends a motion instruction by an upper computer, the substrate is 7A09 aluminum alloy, the size is 300mm x 200mm x 10mm, and the process parameters for the test are as follows: the current is 160A-280A, the forming speed is 1 mm/s-6 mm/s, the protective gas is 99.9999 percent pure argon, and the gas flow is 10L/min.

3. A TIG electric arc additive forming time-varying parameter distance adaptive control method according to claim 1, characterized in that under a size dynamic adaptive control system, a deposition direction is gradually transited from a section 1 to a section i during forming, i is a positive integer larger than 1, the narrow-wide unidirectional forming is performed until the whole forming process is finished, wherein the section i is slower in forming speed relative to the section one, more materials are accumulated in unit time, according to forming process experiment results, the forming speed gain is larger, the forming current time lag is smaller, so that the current heat input needs to be increased in a fuzzy manner section by section through the joint adjustment of forming current and forming speed of each layer, and the material is uniformly spread by energy so as not to be accumulated in the height direction.

4. A TIG arc additive forming time varying parameter distance adaptive control method according to claim 1, wherein an optimal controllable range of the variable width part is 5-11 mm.

5. A time varying parameter distance adaptive control method for TIG arc additive forming according to claim 1, wherein a transition section width of each section is 0.4mm to 0.7mm, and a transition section length of each section is 0.2mm to 0.4 mm.

6. A TIG arc additive forming time varying parameter distance adaptive control method according to claim 1, wherein in the step 3, for the achievement of the desired layer height h of each section, the joint adjustment of the forming speed and the forming current is relied on, and the movement of a welding gun and a three-dimensional workbench is not relied on.

7. A time varying parameter distance self-adaptive control method for TIG arc additive forming according to claim 1, characterized in that in the method for wire arc additive forming of uniformly widened parts, tungsten inert gas arc is used as a heat source to realize accumulation.

Technical Field

The invention belongs to the technical field of TIG electric arc additive manufacturing, and particularly belongs to a forming parameter distance self-adaptive control method of a variable-width part.

Background

On the premise of constructing a resource-saving and environment-friendly society, efficient and accurate forming for constructing metal parts is a hot problem of current research. The TIG electric arc additive manufacturing technology is a novel metal rapid forming technology, has the characteristics of high forming efficiency and low equipment cost, and is relatively rough in the precision of formed parts.

In the prior art, the application number of the prior art is 201710029181.4, which is named as a multilayer double-channel arc additive manufacturing method for an aluminum alloy structural part, and the method adopts a welding machine to provide a heat source and a mechanical arm to perform path planning to perform arc additive manufacturing on the aluminum alloy structural part. Although the arc additive manufacturing of the aluminum alloy structural part with the wall thickness of 10 mm-25 mm can be realized through parameter adjustment, the wall thickness is only a certain value, the continuously-variable forming of the variable-width part cannot be realized, and the step effect of the variable-width part is not solved essentially, so that the forming efficiency of the arc additive forming part is reduced, and the material waste rate of later-stage processing is increased.

The patent application number is 201810100511.9, a wire-filling type additive manufacturing method for a solid aluminum alloy structure adopts a laser-TIG composite heat source, and interaction of laser and electric arc can reduce heat input, refine a formed part structure and improve strength on one hand; on the other hand, the laser can stabilize the electric arc, so that the electric arc is more stable in the multi-layer and multi-channel forming process, and the lapping effect is optimized. Although the heat input in the continuous forming process is reduced and the interlayer retention time is reduced, the interface remelting frequency is still not reduced during the multi-line lap forming, so that certain internal defects are generated, and the continuous layer-by-layer forming performance is not better.

When a non-equal-width structure is formed by TIG electric arc additive forming, a forming unit for planning a traditional forming path is formed by closely arranging and combining a plurality of non-equal straight lines. The multi-path lap joint path planning mode not only reduces the forming efficiency, but also enables the lap joint to be easy to generate cracks and pores; the material removal amount is large in the subsequent finish machining process, so that the production cost is increased; and because the TIG electric arc heat source has high energy density, various defects caused by repeated remelting and lapping are inevitable. Therefore, there is a need to develop a simple and practical method for forming a width-variable component.

Disclosure of Invention

The present invention is directed to solving the above problems of the prior art. A TIG electric arc additive forming time varying parameter distance self-adaptive control method is provided. The technical scheme of the invention is as follows:

the TIG electric arc additive forming time-varying parameter distance self-adaptive control method is used for manufacturing multilayer single-channel width-varying thin-wall part structural parts, and the multilayer single-channel width-varying thin-wall part structural parts are printed and formed through an electric arc additive manufacturing system in a 3D mode, and comprises the following steps:

step 1: carrying out layered slicing on the CAD model of the built variable-width part to obtain data information of each layer of width;

step 2: the unequal-width unit discretizes the width data section by section along the forming direction, subdivides the unequal-width unit into a plurality of unit bodies with equal height and certain width, and the width of each section is i, i +1, i +2 … i + m;

and step 3: determining the height h and the width w of an expected layer of each section according to actual requirements;

and 4, step 4: the forming speed V and the forming current I are used as input quantities, and in the control process of each section, the forming speed V is_iAnd a shaping current I_iThe average width of each segment is w_i(ii) a According to feedback data of visually monitoring the layer height and the layer width in real time, forming the currentDynamic self-adaptive correction of the shape velocity is carried out, and closed-loop control of the size of a deposition layer is realized;

and 5: and (4) repeating the steps 2 to 4 after finishing the forming path of one layer and descending the three-dimensional motion forming platform by the corresponding layer thickness, and continuously forming a next layer of smooth structural unit until the part is processed.

Further, TIG that test platform was built by oneself send an electric arc vibration material disk equipment, electrical power generating system is fornices MW3000, send a machine for argon arc welding automatic wire feeder WF-007A, the silk material is the 7A09 aluminum alloy welding wire that the diameter is 1.2mm, welder fixes on three-dimensional workstation, sends the motion instruction by the host computer, the base plate material is 7A09 aluminum alloy, the size is 300mm 200mm 10mm, the technological parameter of experimental usefulness is: the current is 160A-280A, the forming speed is 1 mm/s-6 mm/s, the protective gas is 99.9999 percent pure argon, and the gas flow is 10L/min.

Furthermore, under a dynamic adaptive control system of the size, the deposition direction gradually transits from a section 1 to a section i along the forming process, wherein i is a positive integer larger than 1, and the narrow-wide unidirectional forming is carried out until the whole forming process is finished, wherein the section i has a slower forming speed relative to the section i, more materials are accumulated in unit time, and the experimental result of the forming process shows that the gain of the forming speed is higher and the time lag of the forming current is smaller, so that the current heat input needs to be increased in a fuzzy manner section by section through the joint adjustment of the forming current and the forming speed of each layer, and the materials are uniformly spread by energy to avoid accumulation in the height direction without depending on the up-down movement of a welding gun and a three-dimensional worktable.

Furthermore, the optimal controllable range of the width-variable part is 5-11 mm.

Furthermore, the width of the transition section of each section is 0.4 mm-0.7 mm, and the length of the transition section of each section is 0.2 mm-0.4 mm.

Further, in the method for forming the uniformly-widened part by the wire arc additive forming, tungsten electrode inert gas electric arc is used as a heat source to realize accumulation.

The invention has the following advantages and beneficial effects:

the invention provides a TIG electric arc additive forming time-varying parameter distance self-adaptive control method. On the premise of ensuring that the height is not changed, the method can automatically form parts with continuously changed widths, eliminate the step effect of the inclined plane, improve the complexity and the forming efficiency of the TIG electric arc additive forming parts and ensure the forming quality.

(1) The traditional forming path planning mode of the unequal-width unit structure is formed by densely arranging and combining a plurality of unequal straight lines, and various defects caused by the overlapping problem are inevitable. According to the TIG electric arc additive forming time-varying parameter distance self-adaptive control method provided by the invention, in the process of manufacturing uniformly-varying parts, the shape of a deposition layer with unequal widths is approximated by adjusting the forming speed and the forming current in a proper interval through the combination of multiple sections of controllable layer widths, and a flat structural unit is continuously formed layer by layer.

(2) The multi-line lap joint is assembled into one-time variable cross section forming, so that the lap joint times and the interface remelting times are reduced, the path is simplified, and the defect of internal stress is avoided. The problem of overlap joint structural defect is reduced from the principle, the complexity and the shaping efficiency of TIG electric arc additive shaping part have greatly been improved, and have better continuation successive layer formability.

(3) On the basis of the principle of priority of design function, the utilization rate of forming materials is improved, the forming time is shortened, and the production cost is reduced. The invention achieves high-quality forming of a wide-width structural member, and the method is easy to automate the forming process.

Drawings

FIG. 1 is a schematic diagram of a preferred embodiment of the present invention for forming a stepped unequal width unit structure, wherein (a) multiple equal width single pass forming, (b) single line widening single pass forming, and (c) variable wall thickness structure forming;

Detailed Description

The technical solutions in the embodiments of the present invention will be described in detail and clearly with reference to the accompanying drawings. The described embodiments are only some of the embodiments of the present invention.

The technical scheme for solving the technical problems is as follows:

the TIG that concrete test platform was built by oneself send an electric arc vibration material disk equipment among this embodiment, its electrical power generating system is Fornes MW3000, send a machine for argon arc welding automatic wire feeder WF-007A, the silk material is the 7A09 aluminum alloy welding wire that the diameter is 1.2mm, welder fixes on three-dimensional workstation, send the motion instruction by the host computer, the base plate material is 7A09 aluminum alloy, the size is 300mm 200mm 10mm, the technological parameter of experimental usefulness is: the current is 160A-280A, the forming speed is 1 mm/s-6 mm/s, the protective gas is 99.9999 percent pure argon, and the gas flow is 10L/min.

Step 1: based on figure 1, a continuously variable-width 11-layer thin-wall part is designed, the length of the designed part is 50mm, the height of the designed part is 21mm, unequal-width units are discretized section by section in the forming direction and are divided into 7 unit bodies with equal height and certain width, the length of each section is 7.15mm, the length of a transition section in the period is 0.3mm, the variation range of the designed expected layer width is 5.5-10 mm, and the height of each layer is h_d1.85mm as shown in figure (a). Meanwhile, a variable-width blade structure shown in a figure (b) is designed, the design layer thickness is 10 layers, the forming mode of the epitaxial layer in the width variation direction is 6 sections of uniform arcs, the designed expected layer width variation range is from 5.5 mm to 10mm, and the height of each expected layer is h_d1.85mm, the total desired height is 1.85 x 10-18.5 mm.

Step 2: in the process of forming the section-by-section unequal-width unit structure, in order to avoid the problems of poor section-to-section connectivity, hump type defects and the like, forming of the equal-height unequal-width unit structure is realized by adopting a control mode of dynamic self-adaption of forming current and forming speed under a closed-loop control system;

and step 3: under a size dynamic self-adaptive control system, the deposition direction gradually transits from the section 1 to the section 7 during forming, and the unidirectional forming from narrow to wide is carried out until the whole forming process is finished. Wherein the seventh stage is slower forming speed relative to the first stage, and accumulates more material per unit time. According to the experimental result of the forming process, the gain of the forming speed is high, the time lag of the forming current is small, and therefore the heat input of the current needs to be increased in a fuzzy manner section by section through the joint adjustment of the forming current and the forming speed of each layer, so that the material is uniformly spread by energy to avoid accumulation in the height direction;

and 4, step 4: the high-intensity arc energy source ensures metallurgical bonding between different forming layers, when a forming path is completed for one layer, the three-dimensional motion forming platform descends by a corresponding layer thickness, the steps are repeated, and a next layer of smooth structure unit is continuously formed until a forming piece is processed;

and 5: a part photo formed by the section-by-section unequal-width unit structure is shown in figure 1, and analysis on the control performance of each section shows that in the figure (a), the final heights of the rest sections basically reach one to one except for the edge collapse of the 7 th section, and the control effects of the first section to the sixth section are stable and convergent. The relative error is calculated to be 3.85%, and the maximum layer width error is 0.45mm in section 1. The wall thickness of the formed part is increased from 5.95mm to 10.07mm section by section, and the shape can be similar to a continuous variable-width thin-wall part. In the graph (b), the absolute error of the wall thickness is 9.1% at the maximum, and the layer width of each segment is also approximately close to the expected value, which meets the design requirement. The forming mode of approaching unequal-width units is controlled section by section and feasible, and the process parameters are adjusted in real time to meet the requirement of dynamic size change;

step 6: by reducing the length of the segments and increasing the number of the total control segments, the width can be changed more continuously, the junction between the segments is smoother, but the number of control loops can be increased, and the complexity of the control scheme is increased. Therefore, further optimization of experimental processes and control parameters is required to improve the quality of the formed part.

Compared with the prior art, the method has the advantages that the multi-line lap joint assembly is carried out into one-time variable cross-section forming, the forming time is shortened, the production cost is reduced, the forming process is completed fully automatically, and the closed-loop control of the size of the deposition layer is realized through dynamic self-adaptive correction of forming current and forming speed according to feedback data of visually monitoring the layer height and the layer width in real time without manual intervention. Compared with the prior art, the TIG electric arc additive forming time-varying parameter distance self-adaptive control method has the advantages that the manufactured uniform variable-width part has higher dimensional accuracy and surface smoothness, and a more efficient direct forming method and a more efficient basic theory are provided for path planning of variable-width thin-wall parts.

The systems, devices, modules or units illustrated in the above embodiments may be implemented by a computer chip or an entity, or by a product with certain functions. It should also be noted that the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other like elements in a process, method, article, or apparatus that comprises the element.

The above examples are to be construed as merely illustrative and not limitative of the remainder of the disclosure. After reading the description of the invention, the skilled person can make various changes or modifications to the invention, and these equivalent changes and modifications also fall into the scope of the invention defined by the claims.