Algorithm for calculating motion relation between crosshead and middle plate of injection molding machine

Abstract

The invention discloses an algorithm for calculating the movement relation between a crosshead and a middle plate of an injection molding machine. The algorithm comprises the following steps: S1, solving the relation between an angle and the movement distance of the crosshead; s2, the function relation between the thrust block and the template is determined; s3, solving the relationship between the moving speed of the middle plate and the time; and S4, calculating the amplification factor of the machine hinge. The relation between the displacement of the middle plate of the machine hinge and the displacement of the crosshead, the relation between the displacement of the middle plate and the time and the relation between the amplification factor of the machine hinge and the time are calculated according to the relation between the displacement of the crosshead and the angles of the machine hinge, and the method is mainly applied to a high-speed injection molding machine which is high in speed and more precise in control compared with other machine types. The corresponding relation between the crosshead displacement X and the middle plate displacement Y is accurately calculated, accumulative errors caused by traditional approximate calculation are reduced, speed dynamic analysis is combined, it is ensured that the movement speed of the middle plate is stable, vibration or impact caused by sudden acceleration change during high-speed operation is avoided, and the more accurate the stroke control is, the smaller the operation cycle is.

Description

Technical Field

[0001] The present invention relates to the field of motion relationship algorithms, and specifically to an algorithm for calculating the motion relationship between the crosshead and the middle plate of an injection molding machine. Background Art

[0002] At present, in the injection molding machine industry, the motion relationship between the crosshead and the middle plate is mainly obtained by selecting several discrete points for data fitting. Although this method is simple and easy to implement, it has obvious limitations: First, the data between two points can only be obtained by interpolation or fitting, which cannot accurately reflect the continuous changes in the actual motion process, resulting in cumulative errors; Second, for high-speed precision injection molding machines, this approximate calculation method is difficult to meet the requirements of high-precision control, which may affect the mold closing accuracy and operating efficiency. The functional relationships between the displacement of the middle plate of the toggle machine and the crosshead displacement, the middle plate displacement and time, and the toggle magnification and time, pairwise. The relationship between the middle plate of the toggle machine and the displacement is also called the relationship between the mold base and the thrust seat. Currently, the relationship between the two is obtained by selecting points at different positions during the displacement of the crosshead and the middle plate and fitting them into a curve. However, this method has certain errors, and the data between two points can only be obtained through data fitting.

[0003] Relevant information is also mentioned in the book "Plastic Machinery Design". However, since the calculation method for the angle between the toggles is not clearly specified, the calculation is relatively incomplete. Therefore, an algorithm for calculating the motion relationship between the crosshead and the middle plate of an injection molding machine is now needed. Summary of the Invention

[0004] The purpose of the present invention is to provide an algorithm for calculating the motion relationship between the crosshead and the middle plate of an injection molding machine. This algorithm accurately calculates the motion relationship between the crosshead and the middle plate and introduces toggle deformation compensation to solve the technical problems mentioned in the background art.

[0005] To achieve the above purpose, the present invention provides the following technical solution: An algorithm for calculating the motion relationship between the crosshead and the middle plate of an injection molding machine, comprising the following steps:

[0006] S1. Obtain the relationship between the angle and the crosshead movement distance: Measure the known toggle structure data. The variable is the crosshead movement distance X, and the middle plate movement distance is y. Measure the distance between the middle plate hinge ear and the tail plate hinge ear when the toggle contracts and the distance between the crosshead and the tail plate hinge ear when the toggle is fully contracted;

[0007] S2. The functional relationship between the thrust seat and the template: Substitute the known crosshead movement distance data into the toggle points for calculation to obtain the middle plate travel distance. Then substitute the known middle plate distance to obtain the crosshead movement travel distance, and calculate the angle data within the established coordinate system;

[0008] S3. Find the relationship between the moving speed of the middle plate and time: By differentiating the functional relationship between the thrust seat and the template with respect to time t, the relationship between the speed and the moving distance of the crosshead can be obtained.

[0009] S4. Calculate the magnification factor of the machine hinge: Substitute different specification data into the formula to measure the total deformation distance of the hook hinge and the long hinge when the machine hinge is straightened, and when the moving distance of the middle plate is clear, the magnification factor M, and substitute it into the formula to compare with the actual data.

[0010] Preferably, in the above S1, establish coordinate information, determine the position and stroke in the target coordinate system, and obtain the angles γ, α, φ, and β in the coordinate system. Specifically:

[0011] Find the angle γ:

[0012]

[0013] Find the angle α:

[0014] α = π - γ - ∠ADG - ∠ADB

[0015]

[0016] As can be seen from the above formula:

[0017] α = π - γ - arccos∠GDA - arccos∠ADB

[0018] Find the angle φ:

[0019] According to the alternate interior angles, ∠ABD = φ + γ + α

[0020]

[0021] φ = arccos∠ABD - α - γ

[0022] Find the angle β:

[0023] EF = DE * sinα - CI

[0024] From this, the angle β can be known:

[0025]

[0026] The above AH is equal to 0.295; the above DE is equal to 0.445; the above DH is equal to 0.38416 - x; the above BE is equal to 0.1557; the above AB is equal to 0.152; the above CI is equal to 0.09; the above BD is equal to 0.359.

[0027] Preferably, the functional relationship between the thrust seat and the template in S2 includes substituting the calculated angles of γ, α, φ, and β into the calculation formula in the kinematic analysis of the toggle mechanism in the plastic machinery manual:

[0028] X c = DE * cosα + CE * cosβ

[0029] Substitute the hinge point positions for calculation, and after modification, it is expressed as:

[0030]

[0031] Functional relationship between the thrust seat and the template:

[0032] y = X c - DK

[0033] Substitute the angles into the above formula to obtain:

[0034] y = DE * COS(π - ARCCOS((GD - X) / ((GD - X)^2 + AH^2)^0.5) - ARCCOS(((GD - X)^2 + AH^2 + BD^2 - AB^2) / (2 * ((GD - X)^2 + AH^2)^0.5 * BD)) - ARCCOS((BD^2 + DE^2 - BE^2) / (2 * BD * DE))) + CE * COS(ARCSIN((DE * SIN(π - ARCCOS((GD - X) / ((GD - X)^2 + AH^2)^0.5) - ARCCOS(((GD - X)^2 + AH^2 + BD^2 - AB^2) / (2 * ((GD - X)^2 + AH^2)^0.5 * BD)) - ARCCOS((BD^2 + DE^2 - BE^2) / (2 * BD * DE))) - CI) / CE)) - DK

[0035] Wherein, DK is the distance between the middle plate hinge ear and the tail plate hinge ear when the machine hinge contracts, which is equal to 0.35115; GD is the distance between the crosshead and the tail plate hinge ear when the machine hinge is fully contracted, which is equal to 0.38416.

[0036] Preferably, in S2, it is necessary to obtain the relationship between the moving distance of the middle plate and the stroke of the crosshead. After measuring the specific moving distance, substitute it into the coordinate system to find the angles of α, γ, and φ. Specifically:

[0037] Find the α angle:

[0038] α = ∠CDE + ∠CDI

[0039]

[0040] α = arcsin∠CDI + arccoss∠CDE

[0041] Find the γ angle:

[0042]

[0043] Find the φ angle:

[0044]

[0045] BJ = BD * cos(α + y)

[0046] It can be obtained that:

[0047]

[0048] Relationship between the moving distance of the middle plate and the crosshead stroke:

[0049] y = L3 (position of the crosshead and the hinge ear of the tail plate when the machine hinge is fully extended) - (BD * Cos(α + γ) - AB * cosφ)

[0050] Substitute the angle into the above formula to obtain:

[0051] y = L3 - (BD * COS(ARCSIN(CI / (CI^2 + (L1 + L2 - X)^2)^0.5) + ARCCOS(((L1 + L2 - X)^2 + DE^2 + CI^2 - CE^2) / (0.89 * (CI^2 + (L1 + L2 - X)^2)^0.5)) + 0.32618) - AB

[0052] * COS(ASIN((0.295 - BD * SIN((ASIN(CI / (CI^2 + (L1 + L2 - X)^2)^0.5) + ACOS(((L1 + L2 - X)^2 + DE^2 + CI^2 - CE^2) / (0.89 * (CI^2 + (L1 + L2 - X)^2)^0.5)) + 0.32618)) / AB)))

[0053] After substituting the angle into the formula, the relationship between the moving distance of the middle plate and the crosshead stroke is confirmed, where X is changed to the moving distance of the middle plate, and the zero position is the position of the middle plate when the machine hinge is fully extended;

[0054] In addition, L1 is the horizontal distance between the hinge ear of the middle plate and the hinge ear of the tail plate when the machine hinge is fully retracted; L2 is the total distance traveled by the middle plate; L3 is the distance between the crosshead and the hinge ear when the machine hinge is fully extended.

[0055] Preferably, in S3, the functional relationship between the thrust seat and the template is differentiated with respect to time t, and the formula for the displacement analysis of the dynamic system is cited.

[0056]

[0057] Let

[0058] CE 2 -(DE*sinα - CI) 2 = v;

[0059]

[0060] Let

[0061] DE*sinα - CI = w; v = CE 2 -w 2

[0062]

[0063] It can be obtained that:

[0064]

[0065] From the above calculations, it can be obtained that:

[0066]

[0067] Substituting the angular data in S2, it can be obtained that:

[0068]

[0069] Since △BED can only rotate around point D, its angular velocity:

[0070]

[0071] Also, since the velocity of point B:

[0072] v B = W D * BD

[0073] According to the velocity projection relationship of the AB rod:

[0074]

[0075] From the above three equations, it can be obtained that:

[0076]

[0077] Thus, the functional expression of the crosshead displacement and the middle plate velocity can be known:

[0078]

[0079] In addition, the displacement of the crosshead is related to the clamping cylinder. Therefore, according to:

[0080] q = v * A; x = v * t

[0081] where q is the system flow rate, A is the area of the rodless cavity of the die-locking cylinder, v is the speed of the die-locking piston rod, and the moving speed of the crosshead is a fixed value. Therefore:

[0082]

[0083] Substitute it into x in the above α, and then the functional relationship between time and the speed of the platen can be obtained.

[0084] Preferably, in the above S4, it can be known from the mechanical system formula in plastic machinery design

[0085] P m = 2 * P e * cosβ

[0086] Substitute it into the torque balance condition to get:

[0087] P e * h e - P b * h b = 0

[0088] By combining the above two equations, we can get:

[0089]

[0090] In addition, it can be known from the decomposition relationship of the combined force that:

[0091] P0 - 2 * P b ** cosφ = 0

[0092] And:

[0093] h b = BD * sin(α + γ + φ)h e = DE * sin(α + β)

[0094] It can be known from the plastic machinery design that the calculation formula of the magnification M is:

[0095]

[0096] Substitute the angle into the above result, it can be obtained that when the platen is straightened, the measured magnification does not match the actual one.

[0097] Compared with the prior art, the beneficial effects of the present invention are:

[0098] 1. By using the relationship between the crosshead displacement and the angles of each hinge, the relationships between the displacement of the middle plate of the hinge machine and the crosshead displacement, the displacement of the middle plate and time, and the amplification factor of the hinge and time are calculated. This is mainly applied to high-speed injection molding machines with relatively high speeds and more precise control compared to other models. Through geometric relationship modeling, the corresponding relationship between the crosshead displacement X and the middle plate displacement Y is accurately calculated, reducing the cumulative error caused by traditional approximate calculations. Combining with dynamic speed analysis, the movement speed of the middle plate is ensured to be stable, avoiding vibration or impact caused by sudden acceleration changes during high-speed operation. The more accurate the stroke control is, the smaller the operating cycle is.

[0099] 2. By comparing the hinge relationships of different machines, the hinge points can be optimized. With a reasonable hinge point diagram, through the deformation compensation calculation mentioned above, the influence of adjusting parameters such as AH and BD on the movement of the middle plate can be simulated for different hinge points. Combining with finite element analysis (FEA), the fatigue life of the hinge under high-frequency movement can be verified, which can make the machine have a longer lifespan. BRIEF DESCRIPTION OF THE DRAWINGS

[0100] Figure 1 It is a schematic diagram of the hinge structure of the present invention;

[0101] Figure 2 It is a schematic diagram of the overall moving stroke state of the present invention;

[0102] Figure 3 It is a schematic diagram of moment balance of the present invention;

[0103] Figure 4 It is a schematic diagram of the cross-sectional area of the long hinge of the present invention;

[0104] Figure 5 It is a schematic diagram of the force decomposition relationship of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0105] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a 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 those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0106] The present invention provides: an algorithm for calculating the movement relationship between the crosshead and the middle plate of an injection molding machine, as Figures 1-5 shown, including the following steps:

[0107] S1. Find the relationship between the angle and the crosshead movement distance: Measure the known data of the machine hinge structure. The variable is the crosshead movement distance X, and the middle plate movement distance is y. Measure the distance between the middle plate hinge ear and the tail plate hinge ear when the machine hinge contracts and the distance between the crosshead and the tail plate hinge ear when the machine hinge is fully contracted. Establish coordinate information, determine the position and stroke in the target coordinate system, and obtain the angles γ, α, φ, and β in the coordinate system. Specifically, taking the PT400II machine hinge structure as an example, as Figure 1 shown is its machine hinge sketch. The variable in the figure is the crosshead movement distance X, and the middle plate movement distance is y:

[0108] Find the γ angle:

[0109]

[0110] Find the α angle:

[0111] α = π - γ - ∠ADG - ∠ADB

[0112] As Figure 1 shown:

[0113]

[0114] From the above formula, it can be seen that:

[0115] α = π - γ - arccos∠GDA - arccos∠ADB

[0116] Find the φ angle:

[0117] As Figure 1 shown, according to the alternate interior angles, ∠ABD = φ + γ + α

[0118]

[0119] φ = arccos∠ABD - α - γ

[0120] Find the β angle:

[0121] EF = DE * sinα - CI

[0122] From this, the β angle can be known:

[0123]

[0124] It is stated that AH is equal to 0.295; DE is equal to 0.445; DH is equal to 0.38416 - x; BE is equal to 0.1557; AB is equal to 0.152; CI is equal to 0.09; BD is equal to 0.359.

[0125] S2. Functional relationship between the thrust seat and the template: Substitute the known crosshead movement distance data into the hinge point position for calculation, find the middle plate travel distance, and then substitute the known middle plate distance to find the crosshead movement travel distance, and calculate the angle data within the established coordinates; the functional relationship between the thrust seat and the template includes substituting the calculated angles of γ, α, φ, and β into the calculation formula in the kinematic analysis of the toggle mechanism in the plastic machinery manual:

[0126] X c = DE * cosa + CE * cosβ

[0127] Substitute the hinge point position for calculation, and after modification, it can be expressed as:

[0128]

[0129] Functional relationship between the thrust seat and the template:

[0130] y = X c - DK

[0131] Substitute the angles into the above formula to obtain:

[0132] y = DE * COS(π - ARCCOS((GD - X) / ((GD - X)^2 + AH^2)^0.5) - ARCCOS(((GD - X)^2 + AH^2 + BD^2 - AB^2) / (2 * ((GD - X)^2 + AH^2)^0.5 * BD)) - ARCCOS((BD^2 + DE^2 - BE^2) / (2 * BD * DE))) + CE * COS(ARCSIN((DE * SIN(π - ARCCOS((GD - X) / ((GD - X)^2 + AH^2)^0.5) - ARCCOS(((GD - X)^2 + AH^2 + BD^2 - AB^2) / (2 * ((GD - X)^2 + AH^2)^0.5 * BD)) - ARCCOS((BD^2 + DE^2 - BE^2) / (2 * BD * DE))) - CI) / CE)) - DK

[0133] Wherein, DK is the distance measured between the middle plate hinge ear and the tail plate hinge ear when the machine hinge contracts, which is equal to 0.35115; GD is the distance between the crosshead and the tail plate hinge ear when the machine hinge is fully contracted, which is equal to 0.38416.

[0134] When determining the relationship between the middle plate movement distance and the crosshead stroke, it is necessary to

[0135] Find the α angle:

[0136] As Figure 2 shown:

[0137] α = ∠CDE + ∠CDI

[0138]

[0139] α = arcsin∠CDI + arccos∠CDE

[0140] Find the angle γ:

[0141]

[0142] Find the angle φ:

[0143]

[0144] BJ = BD * cos(α + γ)

[0145] It can be obtained that:

[0146]

[0147] So the relationship between the moving distance of the middle plate and the crosshead stroke:

[0148] y = L3 (the position of the crosshead and the hinge ear of the tail plate when the machine hinge is fully extended) - (BD * cos(α + γ) - AB * cosφ)

[0149] Substituting the angles into the above formula, it can be obtained that:

[0150] y = L3 - (BD * COS(ARCSIN(CI / (CI^2 + (L1 + L2 - X)^2)^0.5) + ARCCOS(((L1 + L2 - X)^2 + DE^2 + CI^2 - CE^2) / (0.89 * (CI^2 + (L1 + L2 - X)^2)^0.5)) + 0.32618) - AB * COS(ASIN((0.295 - BD * SIN((ASIN(CI / (CI^2 + (L1 + L2 - X)^2)^0.5) + ACOS(((L1 + L2 - X)^2 + DE^2 + CI^2 - CE^2) / (0.89 * (CI^2 + (L1 + L2 - X)^2)^0.5)) + 0.32618)) / AB)))

[0151] After substituting the angles into the formula, the relationship between the moving distance of the middle plate and the crosshead stroke is confirmed, where X is changed to the moving distance of the middle plate, and the zero position is the position of the middle plate when the machine hinge is fully extended;

[0152] In addition, L1 is the horizontal distance between the hinge ear of the middle plate and the hinge ear of the tail plate when the machine hinge is fully retracted; L2 is the total distance traveled by the middle plate; L3 is the distance between the crosshead and the hinge ear when the machine hinge is fully extended.

[0153] S3. Obtain the relationship between the moving speed of the middle plate and time: Take the derivative of the functional relationship between the above-mentioned thrust seat and the template with respect to time t, and refer to the formula for displacement analysis of the dynamic system:

[0154]

[0155] Let

[0156] CE 2 -(DE*sinα - CI) 2 = v;

[0157]

[0158] Let

[0159] DE*sinα - CI = w; v = CE 2 -w 2

[0160]

[0161] It can be obtained that:

[0162]

[0163] From the above calculations, it can be obtained that:

[0164]

[0165] As Figure 2 shown, substituting the angle data in S2, it can be obtained that:

[0166]

[0167] Since △BED can only rotate around point D, its angular velocity

[0168]

[0169] Also, since the velocity of point B

[0170] v B = W D * BD

[0171] According to the velocity projection relationship of the AB rod

[0172]

[0173] From the above three equations, it can be known that:

[0174]

[0175] From this, the functional expression of the crosshead displacement and the middle plate velocity can be known:

[0176]

[0177] From this we can know the function expression of crosshead displacement and middle plate speed, so we can use:

[0178] q=v*A;x=v*t

[0179] q is the system flow, A is the area of ​​the rodless cavity of the clamping cylinder, and v is the speed of the clamping piston rod, that is, the moving speed of the crosshead is a constant value. Therefore:

[0180]

[0181] Substituting it into x in α, we can calculate the functional relationship between time and the speed of the middle plate.

[0182] S4. Calculation of the magnification of the machine hinge: bring different specifications of data into the public notice to measure the total deformation distance of the hook hinge and the long hinge when the machine hinge is straightened and the magnification M when the middle plate moves. Bring it into the public notice for comparison with the actual data. It can be known from the plastic machinery design that

[0183] P m =2*P e *cosβ

[0184] From the moment balance condition, we get

[0185] P e *h e -P b *h b =0

[0186] Combining the above two equations, we can get:

[0187]

[0188] like Figure 5 From the decomposition relationship of the intermediate force, we can know that:

[0189] P0-2*P b *cosφ=0

[0190] and:

[0191] h b =BD*sin(α+γ+φ);h e =DE*sin(α+β)

[0192] From the plastic machinery design, we know the calculation formula of the magnification M:

[0193]

[0194] Taking PT400II as an example, according to the above calculations, when the middle plate is straightened, the stroke is 700mm. At this time, the magnification factor M of the toggle is 913, but the actual magnification factor is 20, which does not match the actual situation. When the toggle is straightened, the long toggle and the hook toggle are under great pressure and will produce certain deformation. After deformation, the moving distance of the middle plate decreases. Perhaps due to this deformation, the magnification factor of the toggle will be correspondingly reduced.

[0195] Most preferably, in S2, substitute x into α, and calculate the functional relationship between time and the speed of the middle plate. The calculation formula is as follows:

[0196] V = DE / BD * (SIN((π - ARCCOS((GD - Q / A * t) / ((GD - Q / A * t)^2 + AH^2)^0.5) - ARCCOS(((GD - Q / A * t)^2 + AH^2 + BD^2 - AB^2) / (2 * ((GD - Q / A * t)^2 + AH^2)^0.5 * BD)) - ARCCOS((BD^2 + DE^2 - BE^2) / (2 * BD * DE)))) + (DE * SIN((π - ARCCOS((GD - Q / A * t) / ((GD - Q / A * t)^2 + AH^2)^0.5) - ARCCOS(((GD - Q / A * t)^2 + AH^2 + BD^2 - AB^2) / (2 * ((GD - Q / A * t)^2 + AH^2)^0.5 * BD)) - ARCCOS((BD^2 + DE^2 - BE^2) / (2 * BD * DE)))) - CI) * COS((π - ARCCOS((GD - Q / A * t) / ((GD - Q / A * t)^2 + AH^2)^0.5) - ARCCOS(((GD - Q / A * t)^2 + AH^2 + BD^2 - AB^2) / (2 * ((GD - Q / A * t)^2 + AH^2)^0.5 * BD)) - ARCCoS((BD^2 + DE^2 - BE^2) / (2 * BD * DE)))) / (CE^2 - (DE * SIN((π - ARCCOS((GD - Q / A * t) / ((GD - Q / A * t)^2 + AH^2)^0.5) - ARCCOS(((GD - Q / A * t)^2 + AH^2 + BD^2 - AB^2) / (2 * ((GD - Q / A * t)^2 + AH^2)^0.5 * BD)) - ARCCOS((BD^2 + DE^2 - BE^2) / (2 * BD * DE)))) - CI)^2)^0.5) * Q / A * cOS(ARCCOS((AB^2 + BD^2 - AH^2 - (GD - Q / A * t)^2) / (2 * AB * BD)) - ARCCOS((BD^2 + DE^2 - BE^2) / (2 * BD * DE)) - (π - ARCCOS((GD - Q / A * t) / ((GD - Q / A * t)2 + AH^2)^0.5) - ARCCOS(((GD - Q / A * t)^2 + AH^2 + BD^2 - AB^2) / (2 * ((GD - Q / A * t)^2 + AH^2)^0.5 * BD)) - ARCCOS((BD^2 + DE^2 - BE^2) / (2 * BD * DE)))) / SIN((π - ARCCOS((GD - Q / A * t) / ((GD - Q / A * t)^2 + AH^2)^0.5) - ARCCOS(((GD - Q / A*t)^2 + AH^2 + BD^2 - AB^2) / (2*((GD - Q / A*t)^2 + AH^2)^0.5*BD)) - ARCCOS((BD^2 + DE^2 - BE^2) / (2*BD*DE))) + ARCCOS((BD^2 + DE^2 - BE^2) / (2*BD*DE)) + ACOS((AB^2 + BD^2 - AH^2 - (GD - Q / A*t)^2) / (2*AB*BD)) - ARCCOS((BD^2 + DE^2 - BE^2) / (2*BD*DE)) - (π - ARCCOS((GD - Q / A*t) / ((GD - Q / A*t)^2 + AH^2)^0.5) - ARCCOS(((GD - Q / A*t)^2 + AH^2 + BD^2 - AB^2) / (2*((GD - Q / A*t)^2 + AH^2)^0.5*BD)) - ARCCOS((BD^2 + DE^2 - BE^2) / (2*BD*DE)))).

[0197] When the middle plate is straightened through the above formula, the magnification factor of the machine hinge does not match the actual situation.

[0198] It should be noted that substituting the angle into the above result in S4 gives

[0199] M = BD / DE * COS(ARCSIN((DE * SIN((-ARCCOS((GD - X) / ((GD - X)^2 + AH^2)^0.5) - ARCCOS(((GD - X)^2 + AH^2 + BD^2 - AB^2) / (2 * ((GD - X)^2 + AH^2)^0.5 * BD)) - ARCCOS((BD^2 + DE^2 - BE^2) / (2 * BD * DE)))) - CI) / CE)) * SIN((π - ARCCOS((GD - X) / ((GD - X)^2 + AH^2)^0.5) - ARCCOS(((GD - X)^2 + AH^2 + BD^2 - AB^2) / (2 * ((GD - X)^2 + AH^2)^0.5 * BD)) - ARCCOS((BD^2 + DE^2 - BE^2) / (2 * BD * DE)))+ARCCOS((BD^2 + DE^2 - BE^2) / (2 * BD * DE)) + ARCCOS((AB^2 + BD^2 - AH^2 - (GD - X)^2) / (2 * AB * BD)) - ARCCOS((BD^2 + DE^2 - BE^2) / (2 * BD * DE)) - (π - ARCCOS((GD - X) / ((GD - X)^2 + AH^2)^0.5) - ARCCOS(((GD - X)^2 + AH^2 + BD^2 - AB^2) / (2 * ((GD - X)2 + AH^2)^0.5 * BD)) - ARCCOS((BD^2 + DE^2 - BE^2) / (2 * BD * DE)))) / COS(ARCCOS((AB^2 + BD^2 - AH^2 - (GD - X)^2) / (2 * AB * BD)) - ARCCOS((BD^2 + DE^2 - BE^2) / (2 * BD * DE)) - (π - ARCCOS((GD - X) / ((GD - X)^2 + AH^2)^0.5) - ARCCOS(((GD - X)^2 + AH^2 + BD^2 - AB^2) / (2 * ((GD - X)^2 + AH^2)^0.5 * BD)) - ARCCOS((BD^2 + DE^2 - BE^2) / (2 * BD * DE)))) / SIN((π - ARCCOS((GD - X) / ((GD - X)^2 + AH^2)^0.5) - ARCCOS(((GD - X)^2 + AH^2 + BD^2 - AB^2) / (2 * ((GD - X)^2 + AH^2)^0.5 * BD)) - ARCCOS((BD^2 + DE^2 - BE^2) / (2 * BD * DE)))+ARCSIN((DE * SIN((π - ARCCOS((GD - X) / ((GD - X)^2 + AH^2)^0.5) - ARCCOS(((GD - X)^2 + AH^2 + BD^2 - AB^2) / (2 * ((GD - X)^2 + AH^2)^0.5 * BD)) - ARCCOS((BD^2 + DE^2 - BE^2) / (2 * BD * DE)))) - CI) / CE)).

[0200] The functional relationship between time and the speed of the middle plate can be accurately obtained through the above formula.

[0201] As Figure 3 、 4 shown in

[0202] A 钩铰 = 0.05 * 0.12 = 0.006 m

[0203] F = 400 T = 4×10 6 N

[0204] The compressive stress on the hook hinge can be obtained as follows:[[]]

[0205]

[0206] The elastic modulus of QT500 - T is:[[]]

[0207] E = 1.69 * 10 11 Pa

[0208] As can be seen from Engineering Mechanics P81:[[]]

[0209] δ x = Eε x

[0210] Combining the above equations, the strain can be obtained as follows:[[]]

[0211] ε x钩铰 = 6.5745×10 -4 m

[0212] After calculating the deformation of the long hinge, the cross - sectional area of the long hinge is:[[]]

[0213] A 长铰 = 0.12 * 0.43 - 3 * 0.067 * 0.08 = 0.03552 m

[0214] F = 400 T = 4×10 6 N

[0215] The compressive stress on the long hinge can be obtained as follows:[[]]

[0216]

[0217] The elastic modulus of QT500 - T is:[[]]

[0218] E=1.69*10 11 Pa

[0219] From Engineering Mechanics P81 we know:

[0220] δ x =Eε x

[0221] Combining the above formulas, we can get the strain:

[0222] ε x长铰 =3.3317×10 -4 m

[0223] So we can get:

[0224] ε x =ε x长铰 +εε x钩铰 =9.9062×10 -4 m

[0225] When the machine hinge is straightened, the hook hinge and the long hinge are deformed by 1mm in total.

[0226] When the moving distance of the middle plate is 699 mm, the magnification M is 19.832, which is consistent with the actual situation.

[0227] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. An algorithm for calculating the motion relationship between the crosshead and the middle plate of an injection molding machine, characterized in that: It includes the following steps: S1. Obtain the relationship between the angle and the crosshead movement distance: By measuring the known data of the machine hinge structure, with the variable being the crosshead movement distance X and the middle plate movement distance being y, measure the distance between the middle plate hinge ear and the tail plate hinge ear during machine hinge contraction and the distance between the crosshead and the tail plate hinge ear when the machine hinge is fully contracted; S2. Functional relationship between the thrust seat and the template: Substitute the known crosshead movement distance data into the machine hinge point position for calculation, obtain the middle plate travel distance, and substitute the known middle plate distance to obtain the crosshead movement travel distance, and calculate the angle data within the established coordinate system; S3. Obtain the relationship between the middle plate movement speed and time: Take the derivative of the above functional relationship between the thrust seat and the template with respect to time t to obtain the relationship between the speed and the crosshead movement distance; S4. Calculate the machine hinge magnification: Substitute different specification data into the formula to measure the total deformation distance of the hook hinge and the long hinge when the machine hinge is straightened, and when the middle plate movement distance is clear, the magnification M, and substitute it into the formula to compare with the actual data situation.

2. The algorithm for calculating the motion relationship between the crosshead and the middle plate of an injection molding machine according to claim 1, wherein: In S1, establish coordinate information, determine the position and travel in the target coordinate system, and obtain the angles γ, α, φ, and β in the coordinate system. Specifically: Obtain the γ angle: Obtain the α angle: α = π - γ - ∠ADG - ∠ADB From the above formula, it can be known that: α = π - γ - arccos∠GDA - arccos∠ADB Obtain the φ angle: According to the alternate interior angles, ∠ABD = φ + γ + α φ = arccos∠ABD - α - γ Obtain the β angle: From this, the β angle can be known: AH is equal to 0.295; DE is equal to 0.445; DH is equal to 0.38416 - x; BE is equal to 0.1557; AB is equal to 0.152; CI is equal to 0.09; BD is equal to 0.

359.

3. An algorithm for calculating the motion relationship between the crosshead and the middle plate of an injection molding machine according to claim 2, characterized in that: In S2, the functional relationship between the thrust seat and the template includes substituting the calculated angles γ, α, φ, and β into the calculation formula in the kinematic analysis of the toggle mechanism in the plastic machinery handbook: X c = DE * cosα + CE * cosβ Substitute the hinge point position into the calculation, and after modification, it can be expressed as: Functional relationship between the thrust seat and the template: y = X c -DK Substitute the angle into the above formula to obtain: y = DE * COS(π - ARCCOS((GD - X) / ((GD - X)^2 + AH^2)^0.5) - ARCCOS(((GD - X)^2 + AH^2 + BD^2 - AB^2) / (2 * ((GD - X)^2 + AH^2)^0.5 * BD)) - ARCCOS((BD^2 + DE^2 - BE^2) / (2 * BD * DE))) + CE * COS(ARCSIN((DE * SIN(π - ARCCOS((GD - X) / ((GD - X)^2 + AH^2)^0.5) - ARCCOS(((GD - X)^2 + AH^2 + BD^2 - AB^2) / (2 * ((GD - X)^2 + AH^2)^0.5 * BD)) - ARCCOS((BD^2 + DE^2 - BE^2) / (2 * BD * DE))) - CI) / CE)) - DK The DK is the distance between the middle plate hinge ear and the tail plate hinge ear when the hinge is retracted, which is equal to 0.35115; the GD is the distance between the crosshead and the tail plate hinge ear when the hinge is fully retracted, which is equal to 0.38416.

4. An algorithm for calculating the motion relationship between the crosshead and the middle plate of an injection molding machine according to claim 3, characterized in that: In S2, it is necessary to obtain the relationship between the moving distance of the middle plate and the crosshead stroke. After measuring the specific moving distance, bring it into the coordinate system to calculate the angles α, Y and φ. Specifically: Find the angle α: α=∠CDE+∠CDI α=arcsin∠CDI+arccos∠CDE Find the gamma angle: Find the angle φ: BJ=BD*cos(α+γ) We can get: Relationship between the middle plate moving distance and the crosshead stroke: y=L3(position of crosshead and tail plate hinge ear when the hinge is straightened)-(BD*cos(α+y)-AB+cosφ) Substituting the angle into the above equation yields: y=L3-(BD*COS(ARCSIN(CI / (CI^2+(L1+L2-X)^2)^0.5)+ARCCOS(((L1+L2-X)^2+DE^2+CI^2-CE^2) / (0.89*(CI^2+(L1+L2-X)^2)^0.5))+0.32618)-AB*COS(A SIN((0.295-BD*SIN((ASIN(CI / (CI^2+(L1+L2-X)^2)^0.5)+ACOS(((L1+L2-X) ^2+DE^2+CI^2-CE^2) / (0.89*(CI^2+(L1+L2-X)^2)^0.5)))+0.32618)) / AB))) After the angle is substituted into the formula, the relationship between the moving distance of the middle plate and the crosshead stroke is confirmed, wherein X is changed to the moving distance of the middle plate, and the zero position is the position of the middle plate when the machine hinge is fully extended; In addition, L1 is the horizontal distance between the middle plate hinge ear and the tail plate hinge ear when the hinge is fully retracted; L2 is the total distance traveled by the middle plate; and L3 is the distance between the crosshead and the hinge ear when the hinge is straightened.

5. An algorithm for calculating the motion relationship between the crosshead and the middle plate of an injection molding machine according to claim 4, characterized in that: In S3, the functional relationship between the thrust seat and the template is derived with respect to time t, and the formula for displacement analysis of the dynamic system is quoted: make make DE*sinα - CI = w; v = CE 2 -w 2 available: From the above calculation, we can get: Substituting the angle data in S2, we get: Since △BED can only rotate around point D, its angular velocity is: And because the speed of point B is: v B = W D * BD According to the AB rod speed projection relationship: From the above three formulas, we can get: From this we can know the functional expression of crosshead displacement and middle plate speed: In addition, the displacement of the crosshead is related to the clamping cylinder, so according to: q=v*A;x=v*t The q is the system flow, the A is the area of ​​the rodless cavity of the clamping cylinder, the v is the speed of the clamping piston rod, and the moving speed of the crosshead is a constant, so: Substitute this into the x in α and find the function relationship between time and the speed of the middle plate.

6. An algorithm for calculating the motion relationship between the crosshead and the middle plate of an injection molding machine according to claim 5, characterized in that: The S4 type can be known from the mechanical system formula in plastic machinery design: P m = 2 * P e * cosβ Substituting into the moment balance condition, we get: P e *h e -P b *h b = 0 Combining the above two equations, we can get: In addition, it can be known from the decomposition relationship of the double elbow member: P0 - 2*P b *cosφ = 0 and: h b = BD * sin(α + γ + φ); h e = DE * sin(α + β) From the plastic machinery design, we know the calculation formula of the magnification M: Substituting the angle into the above result, we get: When the middle plate is straightened, the magnification of the toggle mechanism does not match the actual situation.

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