Spray forming multi-nozzle process parameter optimization method for realizing uniform deposition

Abstract

The invention discloses a spray forming multi-nozzle process parameter optimization method for realizing uniform deposition, which comprises the following steps of: optimizing process parameters, namely eccentric distance e, metal flow rate psi, initial inclination angle alpha and scanning range angle beta which are included in each nozzle and have obvious influence on deposition uniformity; the method comprises the following steps: S1, establishing a multi-nozzle scanning interface deposition numerical model; s2, determining parameter constraints and boundary conditions; and S3, multi-nozzle parameter genetic algorithm optimization. According to the method, coupling and mutual influence among a plurality of process parameters are effectively solved, so that substances deposited on the surface in the multi-nozzle spray forming process are distributed more uniformly, and the density and the structure uniformity of the ingot blank can be effectively improved.

Description

Technical Field

[0001] The invention relates to the technical field of metallurgy, and in particular to a method for optimizing process parameters of a spray forming multi-nozzle for achieving uniform deposition. Background Art

[0002] Spray forming is the process of atomizing a liquid melt in a controlled atmosphere (usually inert) to form a droplet jet, which is then cooled in flight and deposited on a collector in a semi-solid state to fuse into a dense billet. It combines the atomization of liquid metal (rapid solidification) with the deposition of atomized droplets (dynamic dense solidification of droplets) to prepare billets directly from liquid metal in a one-step metallurgical operation. The uniqueness of the spray forming process lies in its rapid solidification process. Only when the atomized spray cone and the surface of the deposited billet are both in a semi-solid deposition state can a material with an ideal microstructure be obtained. The semi-solid solidification process needs to be maintained within a very narrow process window. This places high demands on the spray deposition process parameters and their stability.

[0003] One of the development directions of spray forming process is the large-scale blank. A single nozzle can expand the deposition range of the atomization cone by tilt scanning, but the deposition range is also subject to certain restrictions. Therefore, nozzle scanning + multi-nozzle collaborative spray forming is the main way to achieve large-scale ingots. In the multi-nozzle scanning collaborative spraying process, many process parameters are involved. The parameters of a single nozzle include eccentricity e, initial tilt angle α, scanning range angle β, scanning frequency f, melt flow rate ψ, atomizing gas pressure p and other six parameters; the common parameters include injection height h, deposition disk rotation speed ω, deposition disk pull-down speed v, then n nozzles involve a total of (6n+3) process parameters. These process parameters have a high degree of correlation and have a great influence on the atomization process, material deposition distribution state, and semi-solid solidification and deposition state.

[0004] The uniformity of material distribution and morphology control on the deposition surface during multi-nozzle spray forming are the key to ensuring the density and uniformity of the ingot. Production practice shows that the following problems are prone to occur in multi-nozzle collaborative spray forming: (1) Overlapping of atomization cone deposition. The atomization cones formed by multiple nozzles are prone to overlap, resulting in overspray at the deposition interface, causing local stacking of droplets, uneven deposition interface, and easy formation of loose structure and pore defects; (2) Multiple control parameters and parameter coupling. The coupling relationship between the position layout and motion parameters of multiple atomizers is complex, making it difficult to optimize parameters, which can easily cause coupling and uneven distribution of atomized droplet deposition trajectories.

[0005] In the existing methods for optimizing and formulating process parameters of spray forming, local process parameters are generally optimized and calculated by establishing a theoretical process model of the spray deposition process. The patent "Method for Formulating Process Parameters of Inclined Dual-Nozzle Scanning Spray Forming (201510684086.9)" provides a method and process for optimizing process parameters of dual-nozzle spray forming. However, this method is only for dual nozzles. If there are more nozzles, the calculation process is extremely complicated, and the deposition overlap problem between adjacent nozzles is not considered and solved in this method.

[0006] To this end, we propose a spray forming multi-nozzle process parameter optimization method to achieve uniform deposition. Summary of the invention

[0007] The object of the present invention is to provide a method for optimizing process parameters of a multi-nozzle spray forming system for achieving uniform deposition, so as to solve the problems raised in the above-mentioned background technology.

[0008] To achieve the above object, the present invention provides the following technical solution: a method for optimizing process parameters of a multi-nozzle spray forming process for achieving uniform deposition, wherein the optimized process parameters are the eccentricity e, metal flow rate ψ, initial tilt angle α and scanning range angle β of each nozzle having a significant impact on deposition uniformity, and the method comprises the following steps:

[0009] S1. Establish a numerical model of multi-nozzle scanning interface deposition;

[0010] S2. Determine parameter constraints and boundary conditions;

[0011] S3, genetic algorithm optimization of multi-nozzle parameters.

[0012] In one embodiment of the present invention, the S1 further comprises the following steps:

[0013] S1.1. Establish the instantaneous scanning deposition point P of each nozzle i (t) coordinate, the formula is:

[0014]

[0015] S1.2. Establish the scanning deposition area of ​​each nozzle as follows:

[0016]

[0017] S1.3. Establish the instantaneous deposition rate of each nozzle as:

[0018]

[0019] S1.4. Within the time Δt, the micro-scale height of the single layer of the ingot corresponding to each nozzle is established as:

[0020] Δhi (t) = v i (t)·Δt;i=1,2,...,n (Formula 5);

[0021] S1.5. Establish the spray height h corresponding to each nozzle i (t) can be expressed as:

[0022] h i (t) = h i (t-Δt)+Δh i (t) = h i (t-Δt)-v i (t)·Δt+v0·Δt; i=1,2,...,n

[0023] (Formula 6);

[0024] S1.6, the instantaneous height h i (t) is brought into (Equation 6) to carry out the next deposition process within Δt until the entire deposition process is completed to form a complete ingot. The deposition process model of the deposition surface can be expressed as:

[0025]

[0026] In one embodiment of the present invention, the S2 further comprises the following steps:

[0027] S2.1, eccentricity e parameter constraint:

[0028] The eccentricity indicates the installation position of the nozzle on the top plate of the sedimentation box. If the radius of the sedimentation box is R 箱 , then the nozzle eccentricity satisfies the following constraints:

[0029] (1) The nozzle eccentricity should be greater than 0 mm and not exceed R 箱 , that is, 0<e i <R 箱 ,i=1,2,...,n, and e i-1 <e i ;

[0030] (2) The interval between the first n-1 adjacent nozzles is greater than 50 mm, that is To ensure the height of the outermost ingot, the distance between nozzle n-1 and nozzle n only needs to be greater than 30 mm, that is,

[0031] S2.2, initial inclination angle α parameter constraint:

[0032] (1) The minimum deposition radius of the innermost nozzle should be close to the center point, and the maximum value should not exceed 10 mm, that is: e1-h1(t)·tan(α1+β1)<10;

[0033] (2) To ensure that the ingot diameter meets the process requirements, the maximum deposition radius of the outermost nozzle should be greater than or equal to the ingot radius R 锭 , that is: R 锭 <e n -h n (t)·tan(α n -β n );

[0034] (3) Satisfy the self-regulating convergence condition: α i -β i >0,i=1,2,...,n;

[0035] (4) To ensure that the deposition areas of each nozzle can overlap, the minimum deposition radius of the next nozzle should be smaller than the maximum deposition radius of the previous nozzle, that is:

[0036] e i -h i (t)·tan(α i +β i )<e i-1 -h i (t)·tan(α i-1 -β i-1 ); i = 1, 2, ..., n;

[0037] S2.3, scanning range angle β parameter constraint:

[0038] The reciprocating scanning motion of the nozzle is realized by the motor, cam and connecting rod mechanism. The scanning range angle β is limited to 3°≤β by the reciprocating scanning mechanism. i ≤10°,i=1,2,...,n;

[0039] S2.4, mass flow rate ψ parameter constraint:

[0040] The total melt mass flow rate of the multi-nozzle is specified not to exceed ψ total , and the maximum value of the mass flow rate of each nozzle does not exceed 40% of the minimum value, that is:

[0041]

[0042] In one embodiment of the present invention, the S3 further includes the following steps:

[0043] S3.1, fitness value calculation:

[0044] The fitness value is defined as the height difference of the ingot surface. The deposition point coordinates (x i-1 ,y i-1 ) and the minimum and maximum deposition radius of nozzle i and If the deposition point of nozzle i-1 belongs to the jet overlap region, that is, The number of overlapping points ΔN i-1 =ΔN i-1 +1; After the injection molding process in Δt is completed, the total number of deposition points of nozzle i-1 in Δt can be obtained ΔN i-1 At this time, nozzle i-1 deposits a height Δh on the surface of the ingot within Δt. i-1 Still calculated according to (Formula 4), the current height value of the injection molding area of ​​nozzle i-1 is expressed by (Formula 7):

[0045] Ph i-1 (t) = h i-1 (t-Δt)+Δh i-1 (Formula 8);

[0046] The deposition height of nozzle i on the ingot surface within Δt is determined by the number of overlapping points, as shown in (Equation 9):

[0047]

[0048] Similarly, the current height value of the injection molding area of ​​nozzle i is expressed as:

[0049] Ph i (t) = h i (t-Δt)+Δh i (Formula 10);

[0050] Thus, the height values ​​of the n highest deposition points of the highest layer of the ingot after the deposition process are completed can be obtained: Ph1, Ph2, ..., Ph n , then the height difference of the ingot surface, that is, the fitness value, is expressed as:

[0051] Δh=max(Ph1,Ph2,...,Ph n )-min(Ph1, Ph2, ..., Ph n ) (Formula 11);

[0052] S3.2, perform real number encoding on the nozzle eccentricity e, metal flow rate ψ, initial inclination angle α, and scanning range angle β and add constraints to each parameter;

[0053] The parameters are used as variables to participate in the genetic optimization process and combined with (Equation 8) to (Equation 11) to calculate the fitness values ​​Δh of all individuals in the population, and selection, crossover and mutation operations are performed according to the fitness values.

[0054] In one embodiment of the present invention, in said S3.2, in order to ensure good surface uniformity of the ingot after the deposition process, the individuals with a height difference Δh less than 5 mm are regarded as the optimal individuals, thereby completing the calculation and optimization of the parameter fitness value.

[0055] In summary, due to the adoption of the above technology, the beneficial effects of the present invention are:

[0056] In the present invention, the coupling and mutual influence between many process parameters are effectively solved, so that the material distribution on the deposition surface in the multi-nozzle injection forming process is more uniform, and the density and organizational uniformity of the ingot can be effectively improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] Figure 1 A schematic diagram of multi-nozzle scanning spray forming and its parameters in Example 1 of the present invention;

[0058] Figure 2 This is a schematic diagram of the distribution of multi-nozzle deposition areas in Example 1 of the present invention;

[0059] Figure 3 It is a schematic diagram of the genetic algorithm optimization process of the present invention;

[0060] Figure 4 This is a schematic diagram of the height of a multi-nozzle ingot according to Example 1 of the present invention;

[0061] Figure 5 This is a schematic top view of a multi-nozzle ingot according to Example 1 of the present invention. DETAILED DESCRIPTION

[0062] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the invention claimed for protection, but merely represents the selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0063] In the description of the present invention, it is necessary to understand that the terms indicating orientation or positional relationship are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0064] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances of the specification.

[0065] See also Figure 1-Figure 5 The present invention provides a method for optimizing process parameters of a multi-nozzle spray forming process for achieving uniform deposition, wherein the optimized process parameters are the eccentricity e, metal flow rate ψ, initial tilt angle α and scanning range angle β of each nozzle having a significant impact on deposition uniformity, and the method comprises the following steps:

[0066] S1. Establish a numerical model of multi-nozzle scanning interface deposition;

[0067] S2. Determine parameter constraints and boundary conditions;

[0068] S3, genetic algorithm optimization of multi-nozzle parameters.

[0069] In this embodiment, the S1 further includes the following steps:

[0070] S1.1. Establish the instantaneous scanning deposition point P of each nozzle i (t) coordinate, the formula is:

[0071]

[0072] S1.2. Establish the scanning deposition area of ​​each nozzle as follows:

[0073]

[0074] S1.3. Establish the instantaneous deposition rate of each nozzle as:

[0075]

[0076] S1.4. Within the time Δt, the micro-scale height of the single layer of the ingot corresponding to each nozzle is established as:

[0077] Δh i (t) = v i (t)·Δt;i=1,2,...,n (Formula 5);

[0078] S1.5. Establish the spray height h corresponding to each nozzle i (t) can be expressed as:

[0079] h i (t) = h i (t-Δt)+Δh i (t) = h i (t-Δt)-v i (t)·Δt+v0·Δt; i=1,2,...,n

[0080] (Formula 6);

[0081] S1.6, the instantaneous height h i (t) is brought into (Equation 6) to carry out the next deposition process within Δt until the entire deposition process is completed to form a complete ingot. The deposition process model of the deposition surface can be expressed as:

[0082]

[0083] In this embodiment, S2 further includes the following steps:

[0084] S2.1, eccentricity e parameter constraint:

[0085] The eccentricity indicates the installation position of the nozzle on the top plate of the sedimentation box. If the radius of the sedimentation box is R 箱 , then the nozzle eccentricity satisfies the following constraints:

[0086] (1) The nozzle eccentricity should be greater than 0 mm and not exceed R 箱 , that is, 0<e i <R 箱 ,i=1,2,...,n, and e i-1 <e i ;

[0087] (2) The interval between the first n-1 adjacent nozzles is greater than 50 mm, that is To ensure the height of the outermost ingot, the distance between nozzle n-1 and nozzle n only needs to be greater than 30 mm, that is,

[0088] S2.2, initial inclination angle α parameter constraint:

[0089] (1) The minimum deposition radius of the innermost nozzle should be close to the center point, and the maximum value should not exceed 10 mm, that is: e1-h1(t)·tan(α1+β1)<10;

[0090] (2) To ensure that the ingot diameter meets the process requirements, the maximum deposition radius of the outermost nozzle should be greater than or equal to the ingot radius R 锭 , that is: R 锭 <e n -h n (t)·tan(α n -β n );

[0091] (3) Satisfy the self-regulating convergence condition: α i -β i >0,i=1,2,...,n;

[0092] (4) To ensure that the deposition areas of each nozzle can overlap, the minimum deposition radius of the next nozzle should be smaller than the maximum deposition radius of the previous nozzle, that is:

[0093] e i -h i (t)·tan(α i +β i )<e i-1 -h i (t)·tan(α i-1 -β i-1 ); i = 1, 2, ..., n;

[0094] S2.3, scanning range angle β parameter constraint:

[0095] The reciprocating scanning motion of the nozzle is realized by the motor, cam and connecting rod mechanism. The scanning range angle β is limited to 3°≤β by the reciprocating scanning mechanism. i ≤10°,i=1,2,...,n;

[0096] S2.4, mass flow rate ψ parameter constraint:

[0097] The total melt mass flow rate of the multi-nozzle is specified not to exceed ψ total , and the maximum value of the mass flow rate of each nozzle does not exceed 40% of the minimum value, that is:

[0098]

[0099] In this embodiment, S3 further includes the following steps:

[0100] S3.1, fitness value calculation:

[0101] The fitness value is defined as the height difference of the ingot surface. The deposition point coordinates (x i-1 ,y i-1 ) and the minimum and maximum deposition radius of nozzle i and If the deposition point of nozzle i-1 belongs to the jet overlap region, that is, The number of overlapping points ΔN i-1 =ΔN i-1 +1; After the injection molding process in Δt is completed, the total number of deposition points of nozzle i-1 in Δt can be obtained ΔN i-1 At this time, nozzle i-1 deposits a height Δh on the surface of the ingot within Δt.i-1 Still calculated according to (Formula 4), the current height value of the injection molding area of ​​nozzle i-1 is expressed by (Formula 7):

[0102] Ph i-1 (t) = h i-1 (t-Δt)+Δh i-1 (Formula 8);

[0103] The deposition height of nozzle i on the ingot surface within Δt is determined by the number of overlapping points, as shown in (Equation 9):

[0104]

[0105] Similarly, the current height value of the injection molding area of ​​nozzle i is expressed as:

[0106] Ph i (t) = h i (t-Δt)+Δh i (Formula 10)

[0107] Thus, the height values ​​of the n highest deposition points of the highest layer of the ingot after the deposition process are completed can be obtained: Ph1, Ph2, ..., Ph n , then the height difference of the ingot surface, that is, the fitness value, is expressed as:

[0108] Δh=max(Ph1,Ph2,...,Ph n )-min(Ph1, Ph2, ..., Ph n ) (Formula 11);

[0109] S3.2, perform real number encoding on the nozzle eccentricity e, metal flow rate ψ, initial inclination angle α, and scanning range angle β and add constraints to each parameter;

[0110] The parameters are used as variables to participate in the genetic optimization process and combined with (Equation 8) to (Equation 11) to calculate the fitness values ​​Δh of all individuals in the population, and selection, crossover and mutation operations are performed according to the fitness values.

[0111] In this embodiment, in order to ensure good surface uniformity of the ingot after the deposition process, individuals with a height difference Δh less than 5 mm are regarded as optimal individuals in S3.2, thereby completing the calculation and optimization of parameter fitness values.

[0112] Example 1

[0113] like Figure 1 As shown, taking 4 nozzles as an example,

[0114] Establish a numerical model of multi-nozzle scanning interface deposition.

[0115] The deposition interface behavior is to calculate the micro-scale height of the single layer of the ingot during the deposition process. First, the coordinates of the deposition point are obtained by the multi-nozzle scanning trajectory meter. Then, the deposition area is calculated according to the inner and outer radius areas of the material deposition. On this basis, the growth deposition rate of the ingot surface is calculated in combination with the melt mass flow rate. Finally, the micro-scale height of the single layer of the ingot is obtained. The final height of the ingot is the accumulation and growth of the micro-scale height of the single layer of the ingot.

[0116] Multi-nozzle scanning spray deposition process;

[0117] The instantaneous deposition point P of the i-th nozzle i The coordinates of point (t) are:

[0118]

[0119] The i-th nozzle scans the deposition area as:

[0120]

[0121] Therefore, the area of ​​the deposition area scanned by the i-th nozzle is:

[0122]

[0123] The instantaneous deposition velocity of the i-th nozzle is:

[0124]

[0125] Assuming that the molten metal flowing out of the nozzle is evenly spread within the scanning range at the corresponding moment, the micro-scale height of the ingot single layer (within Δt time) is:

[0126] Δh i (t) = v i (t)·Δt;i=1,2,...,n (Formula 5);

[0127] Under the combined effect of surface deposition and sedimentation, the jet height h i (t) can be expressed as:

[0128] h i (t) = h i (t-Δt)+Δh i (t) = h i (t-Δt)-v i (t)·Δt+v0·Δt; i=1,2,...,n

[0129] (Formula 6);

[0130] The instantaneous height h i(t) is brought into (Equation 6) to carry out the next deposition process within Δt until the entire deposition process is completed to form a complete ingot. The deposition process model of the deposition surface can be expressed as:

[0131]

[0132] Determine the parameters influencing the uniformity of surface deposition,

[0133] The deposition process parameters depend on the nozzle scanning parameters (e, α, β, f), the depositor motion parameters (ω, v0) and the metal flow rate ψ; among them, the scanning frequency f, the substrate pull-down speed v0, and the substrate rotation angular velocity ω have little effect on the deposition uniformity of the ingot surface; the nozzle eccentricity e and the metal flow rate ψ have a large range of values ​​and have a great influence on the deposition area and the deposition rate, thus directly affecting the uniformity of the ingot; the initial tilt angle α and the scanning angle β mainly affect the morphology of the ingot deposition surface; thus, the parameters that need to be optimized in the spray forming process are determined as follows: nozzle eccentricity e, metal flow rate ψ, initial tilt angle α, and scanning angle β;

[0134] Determine parameter constraints and boundary conditions;

[0135] (1) Eccentricity e parameter constraint;

[0136] The eccentricity indicates the installation position of the nozzle on the top plate of the sedimentation box. If the radius of the sedimentation box is R 箱 , then the nozzle eccentricity must satisfy the following constraints:

[0137] The nozzle eccentricity should be greater than 0mm and not exceed R 箱 , that is, 0<e i <R 箱 ,i=1,2,...,n, and e i-1 <e i ;

[0138] ② The interval between the first n-1 nozzles must be greater than 50mm, that is To ensure the height of the outermost ingot, the distance between nozzle n-1 and nozzle n only needs to be greater than 30 mm, that is,

[0139] Initial tilt angle α parameter constraint;

[0140] The minimum deposition radius of the innermost nozzle should be close to the center point, and the maximum value should not exceed 10 mm, that is: e1-h1(t)·tan(α1+β1)<10;

[0141] To ensure that the ingot diameter meets the process requirements, the maximum deposition radius of the outermost nozzle should be greater than or equal to the ingot radius R 锭 , that is: R 锭 <e n -hn (t)·tan(α n -β n );

[0142] Satisfy the self-regulating convergence condition: α i -β i >0,i=1,2,...,n;

[0143] To ensure that the deposition areas of each nozzle can overlap, the minimum deposition radius of the next nozzle should be smaller than the maximum deposition radius of the previous nozzle. That is:

[0144] e i -h i (t)·tan(α i +β i )<e i-1 -h i (t)·tan(α i-1 -β i-1 ); i=1,2,...,n

[0145] Scanning range angle β parameter constraint;

[0146] The reciprocating scanning motion of the nozzle is realized by the motor, cam and connecting rod mechanism. The scanning range angle β is limited by the reciprocating scanning mechanism and has a value range of: 3°≤β i ≤10°,i=1,2,...,n;

[0147] Mass flow rate ψ parameter constraint

[0148] The melt mass flow rate not only affects the deposition rate of the atomizing cone material, but is also an important parameter affecting the melt atomization process and the quality of the droplet atomization. In order to obtain a uniform ingot structure, the melt atomization state of each nozzle should be controlled to be consistent. The melt atomization state mainly depends on the G / M ratio, that is, the ratio of the atomizing gas pressure flow rate to the melt flow rate.

[0149] If the melt mass flow rates of the nozzles vary greatly, the atomizing gas pressures of the nozzles will vary greatly;

[0150] Therefore, the difference range of melt mass flow rate of each nozzle should be limited. In addition, according to the actual injection production situation, the total mass flow rate of each nozzle needs to be controlled to meet the actual conditions;

[0151] The total melt mass flow rate of the multi-nozzle is specified not to exceed ψ total , and the maximum value of the mass flow rate of each nozzle does not exceed 40% of the minimum value, that is:

[0152]

[0153] Genetic Algorithm Optimization of Multi-Nozzle Parameters

[0154] Fitness value calculation;

[0155] The present invention aims at uniform deposition of multiple nozzles, and uses a genetic algorithm to optimize the eccentricity e, metal flow rate ψ, initial tilt angle α, and scanning range angle β of the multiple nozzles. The fitness value is the difference in deposition height of each nozzle on the deposition surface.

[0156] During the deposition process, within each Δt, the position of each nozzle deposition point (X i, Y i ), maximum and minimum deposition radius and Current deposition height Ph of the ingot i ;

[0157] According to the deposition position and the minimum and maximum deposition radius, it is determined whether the current deposition point is in the jet overlap area. Figure 2 As shown (taking 4 nozzles as an example), the red, green, blue and purple areas represent the deposition areas of nozzle 1, nozzle 2, nozzle 3 and nozzle 4, and the intersection of the deposition areas is the overlapping area;

[0158] The single-layer height value of each nozzle spray forming area is adjusted based on the ratio of the number of deposition points in the overlapping area within Δt to the total number of deposition points;

[0159] Taking the spraying process of nozzle i and nozzle i-1 within Δt as an example, the deposition point coordinates (x i-1 ,y i-1 ) and the minimum and maximum deposition radius of nozzle i and If the deposition point of nozzle i-1 belongs to the jet overlap region, that is, The number of overlapping points ΔN i-1 =ΔN i-1 +1; After the injection molding process in Δt is completed, the total number of deposition points of nozzle i-1 in Δt can be obtained ΔN i-1 At this time, nozzle i-1 deposits a height Δh on the surface of the ingot within Δt. i-1 Still calculated according to (Formula 4), the current height value of the injection molding area of ​​nozzle i-1 is expressed by (Formula 5):

[0160] h i-1 (t) = h i-1 (t-Δt)+Δh i-1 (Formula 8)

[0161] The deposition height of nozzle i on the ingot surface within Δt needs to be determined based on the number of overlapping points, as shown in (Equation 9):

[0162]

[0163] Similarly, the current height value of the injection molding area of ​​nozzle i is expressed by (Equation 5) as:

[0164] Ph i (t) = h i (t-Δt)+Δh i (Formula 10)

[0165] Thus, the height values ​​of the n highest deposition points of the highest layer of the ingot after the deposition process are completed can be obtained: Ph1, Ph2, ..., Ph n , then the surface height difference of the ingot (i.e., fitness value) can be expressed as:

[0166] Δh=max(Ph1,Ph2,...,Ph n )-min(Ph1, Ph2, ..., Ph n ) (Formula 11)

[0167] Genetic algorithm process for multi-nozzle parameters;

[0168] The nozzle eccentricity e, metal flow rate ψ, initial tilt angle α, and scanning range angle β are encoded with real numbers and constraints are added to each parameter. The parameters are used as variables in the genetic optimization process and combined with (Equation 8) to (Equation 11) to calculate the fitness values ​​of all individuals in the population (i.e., the surface height difference Δh of the ingot), and selection, crossover, mutation and other operations are performed according to the fitness values. In order to ensure that the surface uniformity of the ingot is good after the deposition process, the individuals with a height difference Δh less than 5mm are regarded as the optimal individuals, thereby completing the parameter fitness value calculation and optimization; the genetic algorithm parameter optimization process is as shown in the attached figure. Figure 3 As shown;

[0169] The number of nozzles is 4, and the radius of the top plate of the deposition box is R 箱 Set the ingot radius R to 450 mm. 锭 is 300 mm, the initial injection height is 600 mm, the substrate rotation speed ω is 8*π / 3, the substrate rotation speed v0 is 0.3 mm / s, and the 4-nozzle scanning frequency f i All are 6HZ, the total mass flow rate of melt ψ total It is 40Kg / min.

[0170] The initial population size of the genetic algorithm is set to 100, the mutation probability is set to 0, the Δh target setting value is set to 5 mm, and the parameter optimization target parameters obtained by the genetic algorithm are shown in Table 1.

[0171] Table 1 Target parameters of parameter optimization process

[0172]

[0173] The optimization results obtained by plotting the parameters in Table 1 are shown in the attached figure. Figure 4 Ingot height diagram and attached Figure 5 As shown in the top view of the ingot, the height difference of the ingot surface calculated by the height value is 4.42mm, which is less than the target setting value of 5mm.

[0174] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

[0175] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

Claims

1. A method for optimizing process parameters of multi-nozzle spray forming to achieve uniform deposition, characterized in that: The optimized process parameters include the eccentricity e, metal flow rate ψ, initial tilt angle α and scanning range angle β of each nozzle which have a significant impact on deposition uniformity. The method includes the following steps: S1. Establish a numerical model of multi-nozzle scanning interface deposition; S2. Determine parameter constraints and boundary conditions; S3. Genetic algorithm optimization of multi-nozzle parameters.

2. The method for optimizing process parameters of a multi-nozzle spray forming process for achieving uniform deposition according to claim 1, characterized in that: The S1 further comprises the following steps: S1.

1. Establish the instantaneous scanning deposition point P of each nozzle i (t) coordinate, the formula is: S1.

2. Establish the scanning deposition area of ​​each nozzle as follows: S1.

3. Establish the instantaneous deposition rate of each nozzle as: S1.

4. Within the time Δt, the micro-scale height of the single layer of the ingot corresponding to each nozzle is established as: Δh i (t) = v i (t)·Δt; i = 1, 2, ..., n (Equation 5); S1.

5. Establish the spray height h corresponding to each nozzle i (t) can be expressed as: h i (t)=h i (t-Δt)+Δh i (t)=h i (t-Δt)-v i (t)·Δt+v0·Δt;i=1,2,...,n (Formula 6); S1.6, the instantaneous height h i (t) is brought into (Equation 6) to carry out the next deposition process within Δt until the entire deposition process is completed to form a complete ingot. The deposition process model of the deposition surface can be expressed as:

3. The method for optimizing process parameters of a multi-nozzle spray forming process for achieving uniform deposition according to claim 2, characterized in that: The S2 further comprises the following steps: S2.1, eccentricity e parameter constraint: The eccentricity indicates the installation position of the nozzle on the top plate of the sedimentation box. If the radius of the sedimentation box is R 箱 , then the nozzle eccentricity satisfies the following constraints: (1) The nozzle eccentricity should be greater than 0 mm and not exceed R 箱 , that is, 0<e i <R 箱 ,i=1,2,...,n, and e i-1 <e i ; (2) The interval between the first n-1 adjacent nozzles is greater than 50 mm, that is To ensure the height of the outermost ingot, the distance between nozzle n-1 and nozzle n only needs to be greater than 30 mm, that is, S2.2, initial inclination angle α parameter constraint: (1) The minimum deposition radius of the innermost nozzle should be close to the center point, and the maximum value should not exceed 10 mm, that is: e1-h1(t)·tan(α1+β1)<10; (2) To ensure that the ingot diameter meets the process requirements, the maximum deposition radius of the outermost nozzle should be greater than or equal to the ingot radius R 锭 , that is: R 锭 <e n -h n (t)·tan(α n -β n ); (3) Satisfy the self-regulating convergence condition: α i -β i >0,i=1,2,...,n; (4) To ensure that the deposition areas of each nozzle can overlap, the minimum deposition radius of the next nozzle should be smaller than the maximum deposition radius of the previous nozzle, that is: teacher i -h i (t)·tan(α i +β i ) and i-1 -h i (t)·tan(α i-1 -β i-1 );i=1,2,...,n; S2.3, scanning range angle β parameter constraints: The reciprocating scanning motion of the nozzle is realized by the motor, cam and connecting rod mechanism. The scanning range angle β is limited to 3°≤β by the reciprocating scanning mechanism. i ≤10°,i=1,2,...,n; S2.4, mass flow rate ψ parameter constraint: The total melt mass flow rate of the multi-nozzle is specified not to exceed ψ total , and the maximum value of the mass flow rate of each nozzle does not exceed 40% of the minimum value, that is:

4. The method for optimizing process parameters of spray forming multi-nozzles for achieving uniform deposition according to claim 1, characterized in that: The S3 further comprises the following steps: S3.1, fitness value calculation: The fitness value is defined as the height difference of the ingot surface. The deposition point coordinates (x i-1 ,y i-1 ) and the minimum and maximum deposition radius of nozzle i and If the deposition point of nozzle i-1 belongs to the jet overlap region, that is, The number of overlapping points ΔN i-1 =ΔN i-1 +1; After the injection molding process in Δt is completed, the total number of deposition points of nozzle i-1 in Δt can be obtained ΔN i-1 At this time, nozzle i-1 deposits a height Δh on the surface of the ingot within Δt. i-1 Still calculated according to (Formula 4), the current height value of the injection molding area of ​​nozzle i-1 is expressed by (Formula 7): Ph i-1 h(t) = i-1 h(t - Δt) + Δh i-1 (Equation 8); The deposition height of nozzle i on the ingot surface within Δt is determined by the number of overlapping points, as shown in (Equation 9): Similarly, the current height value of the injection molding area of ​​nozzle i is expressed as: Ph i h(t) = i h(t - Δt)+Δh i (Equation 10) Thus, the height values ​​of the n highest deposition points of the highest layer of the ingot after the deposition process are completed can be obtained: Ph1, Ph2, ..., Ph n , then the height difference of the ingot surface, that is, the fitness value, is expressed as: Δh=max(Ph1,Ph2,...,Ph n )-min(Ph1, Ph2, ..., Ph n ) (Formula 11); S3.2, perform real number encoding on the nozzle eccentricity e, metal flow rate ψ, initial inclination angle α, and scanning range angle β and add constraints to each parameter; The parameters are used as variables to participate in the genetic optimization process and combined with (Equation 8) to (Equation 11) to calculate the fitness values ​​Δh of all individuals in the population, and selection, crossover and mutation operations are performed according to the fitness values.

5. The method for optimizing process parameters of spray forming multi-nozzle for achieving uniform deposition according to claim 4, characterized in that: In the above S3.2, in order to ensure good surface uniformity of the ingot after the deposition process, the individuals with a height difference Δh less than 5 mm are regarded as the optimal individuals, thereby completing the calculation and optimization of the parameter fitness value.

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