A method for optimizing design of parameters of a toggle type injection molding machine clamping mechanism

Abstract

The present application relates to a kind of elbow type injection molding machine clamping mechanism parameter optimization design method, including model construction step, optimization target configuration step;Parameter selection step;Optimization simulation step;1, the clamping mechanism mathematical model modeling method can be accurately calculated to obtain mechanism position, velocity, force amplification ratio and cylinder force etc.Information.2, the optimization method described in the patent can be optimized to obtain the best clamping mechanism parameters according to different design performance requirements, so as to improve the performance of injection molding machine according to demand.In single-target optimization embodiment, average speed ratio is optimized, and the average speed ratio is improved under the premise that the mold clamping force remains unchanged and the mold plate stroke remains unchanged.3, the optimization method described in the patent is a multi-objective multi-parameter optimization method, and in multi-objective optimization embodiment, average speed ratio and cylinder stroke are optimized, and the average speed ratio is improved under the premise that the mold clamping force remains unchanged and the mold plate stroke remains unchanged, and the cylinder stroke is shortened.

Description

Technical Field

[0001] This invention relates to the field of injection molding machine parameter design, and more specifically, to a method for optimizing the design of parameters of the clamping mechanism of an elbow-type injection molding machine. Background Technology

[0002] Existing three-platen injection molding machines typically employ a double-toggle, five-hinge mechanism as the clamping linkage. This mechanism has a complex shape and numerous design variables. Traditional design calculation methods primarily rely on geometric approaches, depending on experience to determine the values ​​of each parameter without specific optimization analysis. Different industries and machine models have varying requirements for the motion characteristics of the linkage mechanism. However, in actual design work, adjustments to the linkage parameters are often borrowed or only meet a few basic requirements. The clamping mechanism linkage parameters are not optimized for different needs. The lack of a systematic design methodology in the clamping mechanism design process makes it impossible to obtain optimal design parameters based on actual requirements. For new designs with specific performance requirements, such as increasing the speed ratio, force amplification ratio, or stroke ratio, it is impossible to obtain the optimal design parameters. Summary of the Invention

[0003] In view of this, the purpose of this invention is to provide a method for optimizing the design of the clamping mechanism parameters of an elbow-type injection molding machine.

[0004] To solve the above-mentioned technical problems, the technical solution of the present invention is: a method for optimizing the design parameters of the clamping mechanism of a toggle-type injection molding machine.

[0005] The model building steps involve constructing mathematical models for the cylinder position, template position, velocity, overall stiffness, force amplification ratio, and cylinder force, respectively.

[0006] The optimization target configuration steps include determining the optimization task variables and optimization task objectives corresponding to the optimization task.

[0007] The parameter selection steps involve determining the design parameters that need to be optimized and setting the corresponding optimization constraint intervals based on the selected design parameters.

[0008] The optimization simulation process involves substituting the design parameters into the mathematical model within the optimization constraint interval to calculate the optimization task variables. When the values ​​of the optimization task variables satisfy the optimization task objective, the corresponding values ​​of the design parameters are output as the optimization results.

[0009] Furthermore: when the optimization task variable is a single item, the optimization task objective is considered to be satisfied when the value of the optimization task variable is the maximum or minimum.

[0010] Furthermore: When there are multiple optimization task variables, the optimization task objective includes configuring an objective function. The values ​​of the optimization task variables are substituted into the objective function to calculate the output value of the objective function. When the output value is the maximum or minimum, it is considered to satisfy the corresponding optimization task objective.

[0011] Further: the model building step includes a location building sub-step, which includes:

[0012] Step A1: Construct the displacement matrix based on the displacement relationship: in, This is the coordinate transformation matrix;

[0013] Step A2: Establish coordinate system {O} at the center of the tailplate bracket hole, calculate the position of the hydraulic cylinder, and have...

[0014] , ,in, This is a directional description matrix. For position vectors, The horizontal coordinate of the cylinder position is... The vertical coordinate of the cylinder position;

[0015] Calculate the template position.

[0016] , ,in, This is a directional description matrix. For position vectors, The x-coordinate of the template position. The vertical coordinate of the template position;

[0017] Step A3: Construct the expression for the cylinder position With template position .

[0018] Furthermore: the model building step includes a speed building sub-step, which includes:

[0019] Step B1: Construct the velocity Jacobian matrix.

[0020] , ,in, The cylinder velocity vector, The template velocity vector, for The corresponding angular velocity, The velocity Jacobian matrix;

[0021] Step B2: Construct the speed ratio relationship expression. Among them, template speed With cylinder speed .

[0022] Furthermore: the model construction step includes a stiffness construction sub-step, which includes:

[0023] Step C1: Construct the stiffness matrix. ,in, K The overall stiffness matrix of the mold clamping mechanism is... K i ( i =1,2,…, n ) represents the stiffness matrix of each component of the mold clamping mechanism;

[0024] Step C2 J Fi ( i =1,2,…, n ) is in the local coordinate system { O i} Next i Each component is subjected to force F i To the reference coordinate system { O External force F The force transformation matrix has ,

[0025] in, (i=1,2,…, n ) is the first i Local coordinate system of each component { O i The origin is in the reference coordinate system. O The position description vector is below};

[0026] Step C3, for( i =1,2,…, n ) is the first i Local coordinate system of each component { O i In the reference coordinate system { O The orientation description matrix under} has, .

[0027] Furthermore: the model construction step includes a scaling ratio construction sub-step, which includes...

[0028] Step D1: Construct the theoretical amplification formula, which has

[0029]

[0030] Step D2: Calculate the corrected deflection angle based on the friction coefficient.

[0031] ,

[0032] in, For joints i The diameter, For joints i The diameter of the friction circle, The length of the link. The coefficient of friction;

[0033] Step D3: The corrected Substituting the theoretical force amplification ratio M The calculation formula yields the corrected force amplification ratio. ,have

[0034] ,in i fi For joints i The corrected angle, asin() is the arcsine function.

[0035] Furthermore: the model construction step includes a hydraulic cylinder thrust construction sub-step, which includes:

[0036] Step E1, from the maximum clamping force The critical stroke that the template travels after contacting the mold can be calculated. ,have ;

[0037] Step E2: Let the position when the template contacts the mold be... To construct real-time clamping force With template position The expression has ;

[0038] Step E3: From the corrected force amplification ratio M f Accurate real-time hydraulic cylinder thrust calculation F s ;have .

[0039] Furthermore, in the optimization simulation step, the design parameters are substituted using the quasi-Newton method.

[0040] The main technical effects of this invention are reflected in the following aspects: 1. The mathematical modeling method of the clamping mechanism can accurately calculate information such as the mechanism position, speed, force amplification ratio, and cylinder force. 2. The optimization method described in the patent can optimize the optimal clamping mechanism parameters for different design performance requirements, thereby improving the performance of the injection molding machine as needed. In the single-objective optimization embodiment, the average speed ratio is optimized, and the average speed ratio is increased by 10% under the premise that the clamping force and platen stroke remain unchanged. 3. The optimization method described in the patent is a multi-objective, multi-parameter optimization method, which can constrain multiple parameters according to actual needs and select multiple different optimization objectives for in-depth optimization. In the multi-objective optimization embodiment, the average speed ratio and cylinder stroke are optimized, and the average speed ratio is increased by 10% and the cylinder stroke is shortened by 4.3% under the premise that the clamping force and platen stroke remain unchanged. Attached Figure Description

[0041] Figure 1 : A schematic diagram of the positional relationship of the elbow-type injection molding machine clamping mechanism of the present invention. Detailed Implementation

[0042] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings, so that the technical solution of the present invention can be more easily understood and mastered.

[0043] First, refer to Figure 1 As shown, L represents the length of the corresponding link, L1 is the length of the rear support link, L2 is the length of the small link, L3 is the length of the rear link, L4 is the length of the front link, H1 is the height of the tailplate support, H2 is the height of the moving template support, and H3 is the height of the thrust seat support. These are all parameters that can be varied in the design, i.e., the design objectives. For the first turn, For the second turn, For the third turn, The fourth corner is the fourth corner, and these four corners can describe the motion posture of the mold closing mechanism.

[0044] A method for optimizing the parameters of the clamping mechanism of a toggle injection molding machine:

[0045] The model building steps involve constructing mathematical models for the cylinder position, template position, velocity, overall stiffness, force amplification ratio, and cylinder force, respectively.

[0046] The model building steps include a location building sub-step, which includes:

[0047] Step A1: Construct the displacement matrix based on the displacement relationship: in, This is the coordinate transformation matrix;

[0048] Step A2: Establish coordinate system {O} at the center of the tailplate bracket hole. There are two joints from the origin to the cylinder position, requiring two coordinate transformations. The same applies to the template position. Calculate the cylinder position.

[0049] , ,in, This is a directional description matrix. For position vectors, The horizontal coordinate of the cylinder position is... The vertical coordinate of the cylinder position;

[0050] Calculate the template position.

[0051] , ,in, This is a directional description matrix. For position vectors, The x-coordinate of the template position. The vertical coordinate of the template position;

[0052] Step A3, again based on angular relationships i 1= i 3+ β Known i The positions of the hydraulic cylinders can be determined separately. x s ( i 1) Position relative to template x m ( i 1) Constructing the expression for the cylinder position With template position This allows them to be converted into expressions relating angles and corresponding positions, making the mathematical model more computationally efficient.

[0053] The model building steps include a velocity building sub-step, which includes:

[0054] Step B1: Construct the velocity Jacobian matrix.

[0055] , ,in, The cylinder velocity vector, The template velocity vector, for The corresponding angular velocity, The velocity Jacobian matrix;

[0056] Step B2, based on angular relationships i 1= i 3+ β Relationship with angular velocityw 1= w 3. Given w The template velocity v can be obtained separately. mx With the speed v of the hydraulic cylinder sx This allows us to determine the speed ratio between the template speed and the cylinder speed, and construct an expression for the speed ratio. Among them, template speed With cylinder speed .

[0057] The model construction steps include a stiffness construction sub-step, which includes:

[0058] Step C1: Construct the stiffness matrix. ,in, K The overall stiffness matrix of the mold clamping mechanism is... K i ( i =1,2,…, n ) represents the stiffness matrix of each component of the mold clamping mechanism;

[0059] Step C2 J Fi ( i =1,2,…, n ) is in the local coordinate system { O i} Next i Each component is subjected to force F i To the reference coordinate system { O External force F The force transformation matrix has

[0060] ,in, Let the local coordinate system of the i-th component be { O i The origin is in the reference coordinate system. O The position description vector is below};

[0061] Step C3, for( i =1,2,…, n ) is the first i Local coordinate system of each component { O i In the reference coordinate system { O The orientation description matrix under} has, .

[0062] The model building steps include a scaling ratio construction sub-step, which includes...

[0063] Step D1: Construct the theoretical amplification formula, which has

[0064] ;

[0065] Step D2: Calculate the corrected deflection angle based on the friction coefficient.

[0066] ,

[0067] in, d i For joints i The diameter, d fi For joints i The diameter of the friction circle, L i The length of the link. f The coefficient of friction;

[0068] Step D3: The corrected Substituting the theoretical force amplification ratio M The calculation formula yields the corrected force amplification ratio. ,have

[0069] ,

[0070] in i fi For joints i The corrected angle, asin() is the arcsine function.

[0071] The model construction steps include a hydraulic cylinder thrust construction sub-step, which includes:

[0072] Step E1: From the global stiffness matrix K Take the first row and first column. K The term (1,1) represents the stiffness of the mechanism in the x-direction, expressed as... K x Indicated by the maximum clamping force. F max The critical stroke Δ that the template travels after contacting the mold can be calculated. x ,have ;

[0073] Step E2: Let the position when the template contacts the mold be... To construct real-time clamping force With template position The expression has

[0074] ;

[0075] Step E3: From the corrected force amplification ratio Mf Accurate real-time hydraulic cylinder thrust calculation F s ;have, .

[0076] The optimization target configuration steps include determining the optimization task variables and optimization task objectives corresponding to the optimization task.

[0077] The parameter selection steps involve determining the design parameters that need to be optimized and setting the corresponding optimization constraint intervals based on the selected design parameters.

[0078] The optimization simulation process involves substituting the design parameters into the mathematical model within the optimization constraint interval to calculate the optimization task variables. When the values ​​of the optimization task variables satisfy the optimization task objective, the corresponding values ​​of the design parameters are output as the optimization results.

[0079] When the optimization task variable is a single item, the optimization task objective is considered to be satisfied when the value of the optimization task variable is the maximum or minimum.

[0080] Taking the optimization of speed ratio as an example, the optimization variable is set as the average speed ratio. N p Select the link dimensions that need to be optimized as the optimization parameters. X 1. Multiple parameters to be optimized can be selected according to requirements; the constraint range of the link parameters to be optimized can be set. Q 1; within the constrained interval Q The average speed ratio is optimized using the quasi-Newton method to obtain the parameter combination that maximizes the average speed ratio, which is the optimized parameter.

[0081] ,

[0082] ,

[0083] ,

[0084] in, X 1 represents the initial set of parameters to be optimized. N p To optimize the target average speed ratio, Q 1 represents the optimization constraint interval for each parameter variable. X 1new To obtain the optimal parameters, optimize.minimize() is the extreme value convergence function, and BFGS is the extreme value convergence method of the quasi-Newton method.

[0085] Taking the average speed ratio optimization scheme of a certain model as an example, the optimization results show that the average speed ratio is increased by 10% under the premise that the clamping force and the template stroke remain unchanged.

[0086] When there are multiple optimization task variables, the optimization task objective includes a configured objective function. The values ​​of the optimization task variables are substituted into the objective function to calculate its output value. When the output value is maximized or minimized, the corresponding optimization task objective is considered satisfied. Multi-objective optimization:

[0087] Taking the optimization of speed ratio and cylinder stroke as an example, the optimization variable is set as the average speed ratio. N p and cylinder stroke S s Hydraulic cylinder stroke S s It can be obtained from the following formula:

[0088] ,

[0089] in, x smax This is the position where the hydraulic cylinder closes the mold to its lowest point. x smin This is the bottom position of the hydraulic cylinder mold opening.

[0090] Set the optimization objective function as W To make the objective function as small as possible: .

[0091] Select the link dimensions to be optimized as the optimization parameters. X 2. Multiple parameters that need to be optimized can be selected according to requirements; the constraint range of the link parameters to be optimized can be set. Q 2; within the constraint interval Q 2. Using the quasi-Newton method to evaluate the objective function W Optimization calculations are performed to obtain the objective function. W The parameter combination that reaches its minimum value is the optimized parameter.

[0092] ,

[0093] ,

[0094] ,

[0095] in, X 2 represents the initial set of parameters to be optimized. Taking a multi-objective optimization scheme for a certain model as an example, the optimization results show that, under the premise that the clamping force and the template stroke remain unchanged, the average speed ratio is increased by 10% and the cylinder stroke is shortened by 4.3%. This proves that the parameter optimization design method in this paper can improve the performance of the linkage injection molding machine in a targeted manner according to the needs.

[0096] Of course, the above are just typical examples of the present invention. In addition, the present invention may have many other specific embodiments. All technical solutions formed by equivalent substitution or equivalent transformation fall within the scope of protection claimed by the present invention.

Claims

1. A method for optimizing the parameters of the clamping mechanism of a toggle-type injection molding machine, characterized in that: The model building steps involve constructing mathematical models for the cylinder position, template position, velocity, overall stiffness, force amplification ratio, and cylinder force, respectively. The optimization target configuration steps include determining the optimization task variables and optimization task objectives corresponding to the optimization task. The parameter selection steps involve determining the design parameters that need to be optimized and setting the corresponding optimization constraint intervals based on the selected design parameters. The optimization simulation process involves substituting the design parameters into the mathematical model within the optimization constraint interval to calculate the optimization task variables. When the values ​​of the optimization task variables satisfy the optimization task objective, the corresponding values ​​of the design parameters are output as the optimization result. The model building steps include a location building sub-step, which includes: Step A1: Construct the displacement matrix based on the displacement relationship: in, This is the coordinate transformation matrix; Step A2: Establish coordinate system {O} at the center of the tailplate bracket hole, calculate the position of the hydraulic cylinder, and have... , ,in, This is a directional description matrix. For position vectors, The horizontal coordinate of the cylinder position is... The vertical coordinate of the cylinder position; Computing the template position, has , wherein, is the orientation description matrix, is the position vector, is the template position horizontal coordinate, is the template position vertical coordinate; Step A3, constructing expression for ram position with template position ; The model building steps include a velocity building sub-step, which includes: Step B1: Construct the velocity Jacobian matrix. , ,in, The cylinder velocity vector, The template velocity vector, for The corresponding angular velocity, The velocity Jacobian matrix; Step B2, constructing the speed ratio expression, where the template speed is related to the ram speed ; The model construction steps include a stiffness construction sub-step, which includes: Step C1, constructing the stiffness matrix, has wherein, K is the overall stiffness matrix of the mold closing mechanism, K i ( i = 1, 2, …, n is the stiffness matrix of each component of the mold closing mechanism; Step C2 J Fi ( i =1,2,…, n ) is in the local coordinate system { O i } Next i Each component is subjected to force F i To the reference coordinate system { O External force F The force transformation matrix has ,in, (i=1,2,…, n ) is the first i Local coordinate system of each component { O i The origin is in the reference coordinate system. O The position description vector is below}; Step C3, for( i =1,2,…, n ) is the first i Local coordinate system of each component { O i In the reference coordinate system { O The orientation description matrix under} has, ; The model building steps include a scaling ratio construction sub-step, which includes... Step D1, constructing the theoretical magnification formula, has ; Step D2, calculating the correction angle from the friction coefficient, has wherein d i is the diameter of the joint i d fi is the friction circle diameter of the joint i L i is the length of the connecting rod f is the friction coefficient;​​ Step D3, the revised Theoretical force amplification ratio M The formula, the revised force amplification ratio M f , have Wherein θ fi Joint i The revised angle, asin() is the inverse sine function; The model construction steps include a hydraulic cylinder thrust construction sub-step, which includes: Step E1, from the maximum locking force F max The critical travel delta that the template can take after contacting the mold can be calculated x , there is ; Step E2, the position of the template when it contacts the mold is , construct real-time clamp force and template position expressions have ; Step E3: From the corrected force amplification ratio Accurate real-time hydraulic cylinder thrust calculation ;have, .

2. The method of claim 1, wherein: When the optimization task variable is a single item, the optimization task objective is considered to be satisfied when the value of the optimization task variable is the maximum or minimum.

3. The method for optimizing the parameters of the clamping mechanism of a toggle injection molding machine as described in claim 1, characterized in that: When there are multiple optimization task variables, the optimization task objective includes a configured objective function. The values ​​of the optimization task variables are substituted into the objective function to calculate the output value of the objective function. When the output value is the maximum or minimum, it is considered that the corresponding optimization task objective is satisfied.

4. The method of claim 1, wherein: In the optimization simulation step, the design parameters are substituted using the quasi-Newton method.

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