Ultrasonic assisted roll press surface grain refinement method for mold pins

Abstract

This application relates to the field of mold ejector pin processing technology, and particularly to a method for ultrasonic-assisted rolling surface grain refinement of mold ejector pins. The method includes: obtaining the ultrasonic frequency and static pressure of the mold ejector pin; wherein the static pressure includes a first directional force and a second directional force; determining the radial resultant force of the mold ejector pin based on the first directional force and the second directional force; obtaining the amplitude matching frequency of the mold ejector pin based on the radial resultant force and the ultrasonic frequency; determining the feed rotation speed and feed rate of the mold ejector pin according to the amplitude matching frequency; and determining the grain refinement parameters of the mold ejector pin based on the feed rotation speed, feed rate, amplitude matching frequency, ultrasonic frequency, and static pressure. This method solves the problem that slender ejector pins are prone to unilateral radial loads, leading to bending deformation and uneven force distribution in the material field.

Description

Technical Field

[0001] This application belongs to the field of mold ejector pin processing technology, and in particular relates to a method for refining the surface grains of mold ejector pins by ultrasonic-assisted rolling. Background Technology

[0002] Ejector pins in injection molding processes must withstand high-frequency reciprocating ejection motions and high-temperature, high-pressure environments. Their failure modes mainly manifest as surface wear, ejector pin marks, and fatigue fracture. With the widespread application of glass fiber reinforced plastics and the stringent surface quality requirements for transparent parts, the surface properties of ejector pins have become a key factor restricting mold life and product yield.

[0003] In particular, slender ejector pins are prone to generating unilateral radial loads, causing the ejector pins to bend and deform, resulting in a material field defect of "uneven force application". Summary of the Invention

[0004] This application provides a method for refining the surface grains of mold ejector pins by ultrasonic-assisted rolling, which can solve the problem that slender ejector pins are prone to generating unilateral radial loads, causing the ejector pins to bend and deform, resulting in a "uneven force application" defect in the material field.

[0005] In a first aspect, embodiments of this application provide a method for refining the surface grains of a mold ejector pin using ultrasonic-assisted rolling, including: The ultrasonic frequency and static pressure of the mold ejector pin are obtained; wherein, the static pressure includes a first directional force and a second directional force; the first directional force and the second directional force are respectively applied by the first rolling head and the second rolling head symmetrically arranged on both sides of the mold ejector pin, to counteract radial bending load; Based on the first directional force and the second directional force of the mold ejector pin, the radial resultant force of the mold ejector pin is determined; wherein, the radial resultant force reflects the force exerted on the mold ejector pin during bending deformation; Based on the radial resultant force of the mold ejector pin and the ultrasonic frequency, the amplitude matching frequency of the mold ejector pin is obtained; wherein, the amplitude matching frequency is positively correlated with the radial resultant force; The feed rotation speed and feed rate of the mold ejector pin are determined based on the amplitude matching frequency of the mold ejector pin. The grain refinement parameters of the mold ejector pin are determined based on the feed rotation speed, feed speed, amplitude matching frequency, ultrasonic frequency, and static pressure of the mold ejector pin.

[0006] The technical solutions described in this application embodiment have at least the following technical effects: The ultrasonic-assisted rolling surface grain refinement method for mold ejector pins provided in this application embodiment obtains the ultrasonic frequency and static pressure of the mold ejector pin; wherein, the static pressure includes a first directional force and a second directional force; the first directional force and the second directional force are respectively applied by the first rolling head and the second rolling head symmetrically arranged on both sides of the mold ejector pin to counteract radial bending load; based on the first directional force and the second directional force of the mold ejector pin, the radial resultant force of the mold ejector pin is determined; wherein, the radial resultant force reflects the force on the bending deformation of the mold ejector pin; based on the radial resultant force of the mold ejector pin and the ultrasonic frequency, the amplitude matching frequency of the mold ejector pin is obtained; wherein, the amplitude matching frequency is positively correlated with the radial resultant force; according to the amplitude matching frequency of the mold ejector pin, the feed rotation speed and feed speed of the mold ejector pin are determined; according to the feed rotation speed, feed speed, amplitude matching frequency, ultrasonic frequency and static pressure of the mold ejector pin, the grain refinement parameters of the mold ejector pin are determined. This application addresses the issue of ejector pin bending caused by unilateral radial loads by applying first and second directional forces respectively through a first rolling head and a second rolling head symmetrically arranged on both sides of the ejector pin. This counteracts radial bending loads and improves the structural integrity of the ejector pin. Furthermore, it determines the radial resultant force reflecting the ejector pin's bending deformation based on the first and second directional forces, thus satisfying surface plastic deformation requirements while mitigating deformation risks. A positively correlated amplitude matching frequency is obtained based on the radial resultant force and ultrasonic frequency, achieving coordinated adaptation between ultrasonic vibration parameters and radial forces. The feed speed and feed rate are determined according to the amplitude matching frequency, matching the rolling motion with the ultrasonic action rhythm. Finally, grain refinement parameters are determined by comprehensively considering the feed speed, amplitude matching frequency, ultrasonic frequency, and static pressure, achieving unified matching of all process parameters. These methods solve the problem of uneven force distribution in the material field, which easily leads to unilateral radial loads on slender ejector pins, causing bending deformation.

[0007] Secondly, embodiments of this application provide an ultrasonic-assisted rolling surface grain refinement device for mold ejector pins, applied to a double-sided rolling equipment, for implementing the ultrasonic-assisted rolling surface grain refinement method for mold ejector pins as described in any one of the first aspects above. The ultrasonic-assisted rolling surface grain refinement device for mold ejector pins includes: The acquisition unit is used to acquire the ultrasonic frequency and static pressure of the mold ejector pin; wherein, the static pressure includes a first directional force and a second directional force; the first directional force and the second directional force are respectively applied by the first rolling head and the second rolling head symmetrically arranged on both sides of the mold ejector pin, to counteract the radial bending load; A resultant force unit is used to determine the radial resultant force of the mold ejector pin based on the first directional force and the second directional force of the mold ejector pin; wherein the radial resultant force reflects the force exerted on the mold ejector pin during bending deformation; An amplitude unit is used to obtain the amplitude matching frequency of the mold ejector pin based on the radial resultant force and the ultrasonic frequency; wherein the amplitude matching frequency is positively correlated with the radial resultant force. The feed unit is used to determine the feed rotation speed and feed rate of the mold ejector pin based on the amplitude matching frequency of the mold ejector pin. The grain refinement unit is used to determine the grain refinement parameters of the mold ejector pin based on the feed rotation speed, feed speed, amplitude matching frequency, ultrasonic frequency, and static pressure of the mold ejector pin.

[0008] Thirdly, embodiments of this application provide a double-sided rolling device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the method as described in any of the foregoing aspects.

[0009] Fourthly, embodiments of this application provide a computer program product that, when run on a double-sided rolling mill, causes the double-sided rolling mill to perform the method described in any one of the first aspects above.

[0010] It is understood that the beneficial effects of the second to fourth aspects mentioned above can be found in the relevant descriptions in the first aspect mentioned above, and will not be repeated here. Attached Figure Description

[0011] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0012] Figure 1 This is a schematic flowchart of a method for refining the surface grains of a mold ejector pin by ultrasonic assisted rolling, according to an embodiment of this application. Figure 2 This is a model diagram of ultrasonic rolling processing of mold ejector pins provided in an embodiment of this application; Figure 3 This is a schematic diagram of the operation of the ultrasonic-assisted rolling surface grain refinement method for mold ejector pins provided in an embodiment of this application; Figure 4 This is a schematic diagram of the ultrasonic-assisted rolling surface grain refinement device for mold ejector pins provided in this application embodiment; Figure 5 This is a schematic diagram of the structure of the double-sided rolling equipment provided in the embodiments of this application. Detailed Implementation

[0013] In the following description, specific details such as particular system architectures and techniques are set forth for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of this application. However, those skilled in the art will understand that this application may also be implemented in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, apparatuses, circuits, and methods have been omitted so as not to obscure the description of this application with unnecessary detail.

[0014] It should be understood that, when used in this application specification and the appended claims, the term "comprising" indicates the presence of the described features, integrals, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or a collection thereof.

[0015] It should also be understood that the term “and / or” as used in this application specification and the appended claims means any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0016] As used in this application specification and the appended claims, the term "if" may be interpreted, depending on the context, as "when," "once," "in response to determination," or "in response to detection." Similarly, the phrase "if determined" or "if detected [the described condition or event]" may be interpreted, depending on the context, as meaning "once determined," "in response to determination," "once detected [the described condition or event]," or "in response to detection [the described condition or event]."

[0017] Furthermore, in the description of this application and the appended claims, the terms "first," "second," "third," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0018] References to "one embodiment" or "some embodiments" as described in this specification mean that one or more embodiments of this application include a specific feature, structure, or characteristic described in connection with that embodiment. Therefore, the phrases "in one embodiment," "in some embodiments," "in other embodiments," "in still other embodiments," etc., appearing in different parts of this specification do not necessarily refer to the same embodiment, but rather mean "one or more, but not all, embodiments," unless otherwise specifically emphasized. The terms "comprising," "including," "having," and variations thereof mean "including but not limited to," unless otherwise specifically emphasized.

[0019] In related technologies, mold ejector pins need to withstand high-frequency reciprocating ejection motions and high-temperature, high-pressure environments during injection molding. Their failure modes mainly manifest as surface wear, ejector pin marks, and fatigue fracture. With the widespread application of glass fiber reinforced plastics and the stringent surface quality requirements for transparent parts, the surface properties of ejector pins have become a key factor restricting mold life and product yield.

[0020] In particular, slender ejector pins are prone to generating unilateral radial loads, causing the ejector pins to bend and deform, resulting in a material field defect of "uneven force application".

[0021] To address the aforementioned problems, embodiments of this application provide a method for ultrasonic-assisted rolling surface grain refinement of a mold ejector pin. This method includes: acquiring the ultrasonic frequency and static pressure of the mold ejector pin; wherein the static pressure includes a first directional force and a second directional force; the first directional force and the second directional force are applied by a first rolling head and a second rolling head symmetrically arranged on both sides of the mold ejector pin, respectively, to counteract radial bending loads; determining the radial resultant force of the mold ejector pin based on the first directional force and the second directional force; wherein the radial resultant force reflects the force exerted on the mold ejector pin during bending deformation; obtaining the amplitude matching frequency of the mold ejector pin based on the radial resultant force and the ultrasonic frequency; wherein the amplitude matching frequency is positively correlated with the radial resultant force; determining the feed rotation speed and feed rate of the mold ejector pin according to the amplitude matching frequency; and determining the grain refinement parameters of the mold ejector pin based on the feed rotation speed, feed rate, amplitude matching frequency, ultrasonic frequency, and static pressure. This application addresses the issue of ejector pin bending caused by unilateral radial loads by applying first and second directional forces respectively through a first rolling head and a second rolling head symmetrically arranged on both sides of the ejector pin. This counteracts radial bending loads and improves the structural integrity of the ejector pin. Furthermore, it determines the radial resultant force reflecting the ejector pin's bending deformation based on the first and second directional forces, thus satisfying surface plastic deformation requirements while mitigating deformation risks. A positively correlated amplitude matching frequency is obtained based on the radial resultant force and ultrasonic frequency, achieving coordinated adaptation between ultrasonic vibration parameters and radial forces. The feed speed and feed rate are determined according to the amplitude matching frequency, matching the rolling motion with the ultrasonic action rhythm. Finally, grain refinement parameters are determined by comprehensively considering the feed speed, amplitude matching frequency, ultrasonic frequency, and static pressure, achieving unified matching of all process parameters. These methods solve the problem of uneven force distribution in the material field, which easily leads to unilateral radial loads on slender ejector pins, causing bending deformation.

[0022] The ultrasonic-assisted rolling surface grain refinement method for mold ejector pins provided in this application embodiment can be applied to a double-sided rolling equipment. In this case, the double-sided rolling equipment is the main body for executing the ultrasonic-assisted rolling surface grain refinement method for mold ejector pins provided in this application embodiment. This application embodiment does not impose any restrictions on the specific type of double-sided rolling equipment.

[0023] Please see Figure 2 , Figure 2 This is a model diagram of ultrasonic rolling processing of mold ejector pins provided in one embodiment of this application. For example, a double-sided rolling equipment CNC ultrasonic rolling machine tool, the main body of which includes a first rolling head and a second rolling head symmetrically installed. The double-sided rolling equipment can collect the first and second directional forces acting on the ejector pin in real time, automatically calculate the radial resultant force, and dynamically match the ultrasonic frequency and amplitude matching frequency according to the ejector pin material and size, thereby outputting an appropriate feed speed and feed rate, and finally completing the surface grain refinement processing according to the overall process coordinated parameters. The double-sided rolling equipment includes a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements the method as described in any of the above aspects.

[0024] To better understand the ultrasonic-assisted rolling surface grain refinement method for mold ejector pins provided in this application embodiment, the specific implementation process of the ultrasonic-assisted rolling surface grain refinement method for mold ejector pins provided in this application embodiment will be described by way of example below.

[0025] Figure 1 A schematic flowchart of the ultrasonic-assisted rolling surface grain refinement method for mold ejector pins provided in this application embodiment is shown. Figure 3 This illustration shows a schematic diagram of the operation of the ultrasonic-assisted rolling surface grain refinement method for mold ejector pins provided in this application embodiment. The ultrasonic-assisted rolling surface grain refinement method for mold ejector pins includes: S100, obtain the ultrasonic frequency and static pressure of the mold ejector pin, the static pressure including a first directional force and a second directional force. The first directional force and the second directional force are applied by a first rolling head and a second rolling head symmetrically arranged on both sides of the mold ejector pin, respectively, to counteract the radial bending load.

[0026] It can be understood that ultrasonic frequency refers to the frequency of ultrasonic vibration applied to the mold ejector pin, measured in Hertz (Hz). For example, if the mold ejector pin is made of SKD61 material and has a diameter of 8mm, the ultrasonic frequency selected during processing can be set to 20kHz. The ultrasonic frequency can be adapted to the ejector pin size to achieve efficient vibration. Static pressure refers to the constant pressure applied to the ejector pin surface by the rolling head, measured in Newtons (N), used to balance the radial force during ejector pin processing. The first directional force and the second directional force are a pair of opposing forces applied symmetrically. For example, the first rolling head applies a first directional force of 150N towards the ejector pin axis, while the second rolling head applies a second directional force of 150N in the opposite direction. Radial bending load refers to the bending force perpendicular to the ejector pin axis generated by uneven force during ejector pin processing. If it is not counteracted, it will cause the ejector pin to bend and deform, affecting the processing accuracy.

[0027] S200, based on the first and second directional forces of the mold ejector pin, determines the radial resultant force of the mold ejector pin, which reflects the force on the mold ejector pin under bending deformation.

[0028] It can be understood that radial resultant force refers to the total force acting on the radial direction of the ejector pin after the first directional force and the second directional force are vectored together. The unit is Newton (N). The magnitude and direction of the radial resultant force directly reflect the strength of the bending force on the ejector pin. For example, if the first directional force is 150N (pointing towards the axis) and the second directional force is 145N (away from the axis), then the radial resultant force is 5N (pointing towards the axis), indicating that the ejector pin is still subjected to a slight bending force pointing towards the axis and needs further adjustment. Bending deformation refers to the axial deviation of the ejector pin under the action of radial force. For example, if the radial resultant force is too large during ejector pin processing, it will cause the ejector pin axis to bend, resulting in a "crooked pin" phenomenon, which affects the ejection accuracy of the mold.

[0029] As an optional embodiment of this application, S200, determining the radial resultant force of the mold ejector pin based on the first directional force and the second directional force of the mold ejector pin includes: S210, based on the first directional force and the first directional coefficient, the first radial force is obtained.

[0030] It can be understood that the first directional coefficient is a proportional coefficient for correcting the first directional force. It has no unit and is used to compensate for the force error caused by the installation deviation of the first rolling head. For example, if there is a slight offset when the first rolling head is installed, the first directional coefficient is set to 0.98. When the first directional force is 150N, the first radial force = 150N × 0.98 = 147N. The first radial force refers to the force that actually acts on the radial direction of the ejector pin after being corrected by the directional coefficient. It is the basis for subsequent calculation of the radial resultant force.

[0031] S220, based on the second directional force and the second directional coefficient, the second radial force is obtained. The first directional coefficient and the second directional coefficient are obtained according to the installation accuracy of the rolling head.

[0032] It is understandable that the second directional coefficient has the same function as the first directional coefficient, used to correct the deviation of the second directional force. For example, if the installation accuracy of the second rolling head is slightly higher than that of the first rolling head, and the second directional coefficient is set to 0.99, when the second directional force is 145N, the second radial force = 145N × 0.99 = 143.55N. The installation accuracy of the rolling head refers to the coaxiality and symmetry deviation between the rolling head and the ejector pin. The higher the installation accuracy, the closer the directional coefficient is to 1. For example, if the coaxiality deviation of the rolling head installation is ≤0.01mm, the directional coefficient can be set to 0.99~1.0. If the deviation is ≥0.03mm, the directional coefficient needs to be adjusted to 0.95~0.98 to avoid excessive force value correction deviation.

[0033] S230, based on the first radial force and the second radial force, the resultant radial force of the mold ejector pin is obtained.

[0034] As can be understood, based on the example above, the first radial force is 147N (pointing towards the axis), and the second radial force is 143.55N (away from the axis). By vector synthesis, the radial resultant force is calculated as 147N - 143.55N = 3.45N (pointing towards the axis). The calculation result of the radial resultant force can accurately reflect the actual bending force borne by the ejector pin, providing an accurate basis for subsequent amplitude adjustment. If the original directional force is used directly without the correction of the first and second radial forces, the radial resultant force calculation error will be caused by installation deviation, affecting the setting of subsequent processing parameters.

[0035] By adopting the above steps S210 to S230, it is helpful to correct the force deviation caused by insufficient installation accuracy of the rolling head, improve the calculation accuracy of the radial resultant force, and avoid problems such as pin bending deformation and decreased processing accuracy caused by radial resultant force calculation errors.

[0036] In one possible implementation, S230, the radial resultant force of the mold ejector pin is obtained based on the first radial force and the second radial force, including: S231, based on the first radial force and the second radial force, determines the directional characteristics of the mold ejector pin.

[0037] It can be understood that directional characteristics refer to the directional relationship between the first radial force and the second radial force relative to the ejector pin axis. They are mainly divided into two types: "pointing towards the axis" and "away from the axis". For example, in the previous text, the first radial force of 147N points towards the axis, and the second radial force of 143.55N moves away from the axis. This is the directional characteristic of the ejector pin under the current working condition. If both radial forces point towards the axis, the directional characteristic is "pointing in the same direction". If both move away from the axis, the directional characteristic is "moving away in the same direction". The directional characteristic directly determines the calculation method of the radial resultant force.

[0038] S232, based on the directional characteristics, calculate the sum of the first radial force and the second radial force to obtain the resultant radial force of the mold ejector pin.

[0039] It is understandable that, considering the directional characteristics and the previous example, since the first radial force points towards the axis and the second radial force moves away from the axis, and their directions are opposite, the "summation" is actually a vector subtraction, that is, the radial resultant force = radial force pointing towards the axis - radial force moving away from the axis = 147N - 143.55N = 3.45N; if the directional characteristics are that both radial forces point towards the axis, then the summation is the addition of the two values ​​to obtain the radial resultant force pointing towards the axis; if both are moving away from the axis, then the summation is the addition of the two values ​​to obtain the radial resultant force moving away from the axis, so that the calculation of the radial resultant force conforms to the actual force situation.

[0040] By adopting the above steps S231 to S232, the directional relationship between the first and second radial forces can be clarified, avoiding errors in the calculation of radial resultant force due to confusion of directions. At the same time, by classifying the calculation by directional characteristics, it can be adapted to different rolling processing conditions (such as symmetrical offset of the rolling head, unilateral force deviation, etc.), improving the universality and accuracy of radial resultant force calculation, and further ensuring the machining accuracy of the ejector pin.

[0041] For example, in S232, based on the directional characteristics, the sum of the first radial force and the second radial force is calculated to obtain the radial resultant force of the mold ejector pin, including: S2321, based on directional characteristics, assign directional values ​​to the first radial force and the second radial force, record the first radial force pointing towards the center of the ejector pin as a positive value, and record the second radial force away from the center of the ejector pin as a negative value.

[0042] It is understandable that the direction assignment is to convert the direction of the radial force into a calculable numerical symbol, so as to obtain the radial resultant force through mathematical calculation. For example, based on the previous working condition, the first radial force of 147N (pointing towards the axis) is assigned a value of +147N, and the second radial force of 143.55N (away from the axis) is assigned a value of -143.55N. If there are multiple radial forces, they can be uniformly assigned values ​​according to the rule of "positive for pointing towards the axis and negative for away from the axis", so that the direction of all radial forces can be clearly distinguished by the symbol, avoiding direction confusion during calculation.

[0043] S2322, based on the positive value of the first radial force and the negative value of the second radial force, the radial resultant force of the mold ejector pin is obtained.

[0044] It is understandable that, based on the previous assignment results, the radial resultant force = first radial force assignment + second radial force assignment = (+147N) + (-143.55N) = 3.45N. The calculation result of the radial resultant force includes both the magnitude and the direction (positive value indicates pointing towards the axis, negative value indicates away from the axis). For example, if the first radial force is assigned a value of +150N and the second radial force is assigned a value of -150N, then the radial resultant force is 0N, indicating that the ejector pin is radially balanced and there is no risk of bending deformation. If the resultant force after assignment is -5N, it indicates that the ejector pin is subjected to bending force away from the axis, and the pressure of the rolling head needs to be adjusted.

[0045] By adopting the above steps S2321 to S2322, it is helpful to transform the abstract directional characteristics into specific numerical symbols, simplify the calculation process of radial resultant force, reduce calculation errors, and improve the stability and accuracy of ejector machining.

[0046] S300, based on the radial resultant force of the mold ejector pin and the ultrasonic frequency, obtains the amplitude matching frequency of the mold ejector pin, and the amplitude matching frequency is positively correlated with the radial resultant force.

[0047] It can be understood that the amplitude matching frequency refers to the ultrasonic vibration frequency that matches the current radial resultant force and ultrasonic frequency of the ejector pin, and the unit is Hertz (Hz). The core function of the amplitude matching frequency is to match the vibration amplitude of the ejector pin with the force state. For example, in the previous working condition, the radial resultant force is 3.45N and the ultrasonic frequency is 20kHz. If the amplitude matching frequency is positively correlated with the radial resultant force, the amplitude matching frequency can be calculated to be 20.2kHz (the larger the radial resultant force, the higher the amplitude matching frequency). The positive correlation means that when the radial resultant force increases, the amplitude matching frequency increases accordingly, and when the radial resultant force decreases, the amplitude matching frequency decreases accordingly. This is because the larger the radial resultant force, the larger the vibration amplitude of the ejector pin needs to counteract the bending load, and the amplitude matching frequency is the key parameter for achieving the vibration amplitude to counteract the bending load.

[0048] As an optional embodiment of this application, S300, based on the radial resultant force of the mold ejector pin and the ultrasonic frequency, obtains the amplitude matching frequency of the mold ejector pin, including: S310, based on ultrasonic frequency, obtains the material correlation coefficient of the mold ejector pin.

[0049] In one possible implementation, S310, based on the ultrasonic frequency, obtains the material correlation coefficient of the mold ejector pin, including: As we can understand, the material correlation coefficient is a parameter reflecting the response characteristics of mold ejector pin materials (such as SKD61, H13, etc.) to ultrasonic vibration. It has no unit and the value of the material correlation coefficient is related to the material's density, elastic modulus, and damping coefficient. For example, for an SKD61 ejector pin at an ultrasonic frequency of 20kHz, the material correlation coefficient can be set to 0.85, while for an H13 ejector pin at the same ultrasonic frequency, the material correlation coefficient can be set to 0.82, because the elastic modulus of the two materials is different, resulting in different responses to ultrasonic waves. The material correlation coefficient is used to correct the influence of ultrasonic frequency on ejector pin amplitude, so that the amplitude matching frequency calculation closely matches the actual material properties of the ejector pin.

[0050] S311, Obtain the material feature template for each mold ejector pin.

[0051] It is understandable that the material feature template is a pre-stored set of feature parameters corresponding to different ejector pin materials, including key information such as material density, elastic modulus, damping coefficient, and ultrasonic response threshold. For example, for an ejector pin made of SKD61 material, the material feature template for SKD61 material ejector pin will record: density 7.85 g / cm³, elastic modulus 210 GPa, damping coefficient 0.005, and response coefficient 0.85 at an ultrasonic frequency of 20 kHz; for H13 material, the template will record the corresponding parameters, which facilitates the rapid matching of material characteristics according to the ultrasonic frequency in the future, eliminating the need to re-detect material parameters for each processing, thus improving processing efficiency.

[0052] S312, based on ultrasonic frequency, performs feature extraction to obtain ultrasonic frequency feature data.

[0053] Feature extraction can be understood as extracting key data related to material response from ultrasonic frequency signals, including frequency amplitude, frequency stability, and harmonic components. For example, feature extraction of a 20kHz ultrasonic frequency signal yields a frequency amplitude of 10V, frequency stability of ±0.1kHz, and harmonic components ≤5%. These data reflect the actual output state of the ultrasonic frequency. Frequency feature data serves as a bridge connecting ultrasonic frequency and material correlation coefficients. Different frequency feature data correspond to different material responses, thereby determining the corresponding material correlation coefficients.

[0054] S313, based on the material characteristic template and frequency characteristic data, the material correlation coefficient is obtained.

[0055] Understandably, referring to the example above, if the ejector pin material is SKD61, the material feature template of the SKD61 ejector pin records a response coefficient range of 0.83~0.87 at a 20kHz ultrasonic frequency. The frequency feature data obtained through feature extraction (frequency amplitude 10V, stability ±0.1kHz) can be matched with the corresponding material correlation coefficient of 0.85. If the frequency stability deviation in the frequency feature data is large (e.g., ±0.3kHz), the material correlation coefficient needs to be adjusted to 0.83 to compensate for the influence of frequency instability on the material response, so that the material correlation coefficient matches the actual working conditions.

[0056] By employing the steps S311 to S313 described above, it is possible to quickly and accurately obtain the material correlation coefficient that is compatible with the current ultrasonic frequency and the ejector pin material, avoiding coefficient errors caused by the mismatch between material properties and ultrasonic frequency. At the same time, by using the preset material feature template, the material parameter detection steps during each processing are reduced, improving processing efficiency. Furthermore, based on the matching method of frequency feature data, the material correlation coefficient can be dynamically adjusted to adapt to different ultrasonic frequency output states.

[0057] S320, based on the radial resultant force of the mold ejector pin, ultrasonic frequency and material correlation coefficient, obtains the amplitude matching frequency of the mold ejector pin.

[0058] It is understandable that, based on the parameters mentioned above, with an ultrasonic frequency of 20kHz, a material correlation coefficient of 0.85, and a radial resultant force of 3.45N, and a fine-tuning coefficient of 0.0001kHz / N, the amplitude matching frequency can be obtained through a preset formula (e.g., amplitude matching frequency = ultrasonic frequency × material correlation coefficient + radial resultant force ÷ 1000). Therefore, the amplitude matching frequency is approximately 17.000345kHz. If the radial resultant force increases to 5N while the material correlation coefficient remains unchanged, the amplitude matching frequency is approximately 17.0005kHz. The amplitude matching frequency is positively correlated with the radial resultant force, thus ensuring that the vibration amplitude of the ejector pin matches the force state.

[0059] In one possible implementation, S320, based on the radial resultant force of the mold ejector pin, the ultrasonic frequency, and the material correlation coefficient, obtains the amplitude matching frequency of the mold ejector pin, including: S321, based on the material correlation coefficient and ultrasonic frequency, obtains the fundamental frequency of the mold ejector pin amplitude.

[0060] It can be understood that the fundamental frequency of amplitude is the basic vibration frequency of the ejector pin based on material properties and ultrasonic frequency when the radial resultant force is not considered. The unit is Hz. For example, combining the parameters mentioned above, the ultrasonic frequency is 20kHz and the material correlation coefficient is 0.85. The fundamental frequency of amplitude is calculated by the formula (fundamental frequency of amplitude = ultrasonic frequency × material correlation coefficient): 20kHz × 0.85 = 17kHz. The fundamental frequency of amplitude is the basis of the ejector pin vibration and reflects the degree of material properties' response to ultrasonic frequency. If the material correlation coefficient increases, the fundamental frequency of amplitude will also increase, indicating that the material is more sensitive to ultrasonic waves.

[0061] S322, the amplitude matching frequency of the mold ejector pin is obtained by finely adjusting the basic frequency of the radial resultant force.

[0062] It can be understood that fine-tuning refers to making small adjustments to the fundamental frequency of the amplitude based on the magnitude of the radial resultant force, so that the frequency matches the force state of the ejector pin. For example, if the fundamental frequency of the amplitude is 17kHz and the radial resultant force is 3.45N, and the fine-tuning coefficient is set to 0.0001 (unit: kHz / N), then the fine-tuning amount = 3.45N × 0.0001kHz / N = 0.000345kHz. Therefore, the amplitude matching frequency = 17kHz + 0.000345kHz ≈ 17.000345kHz (the fine-tuning coefficient here is only an example, and the actual setting needs to be based on the machining conditions). If the radial resultant force is 0N and the fine-tuning amount is 0, the amplitude matching frequency is the fundamental frequency of the amplitude, indicating that the force on the ejector pin is balanced, and no frequency adjustment is needed.

[0063] By employing the steps S321 to S322 described above, it is helpful to first determine the basic vibration frequency of the ejector pin using the material correlation coefficient and ultrasonic frequency, and then make precise fine adjustments in conjunction with the radial resultant force, avoiding amplitude matching frequency deviation caused by direct calculation. At the same time, the step-by-step adjustment can clearly distinguish the influence of material properties and stress state on the frequency, which is convenient for subsequent parameter adjustment. This ensures that the amplitude matching frequency can not only adapt to the material properties, but also counteract the bending load caused by the radial resultant force, thus ensuring the stability of the ejector pin vibration and the machining accuracy.

[0064] By adopting the above steps S310 to S320, it is helpful to integrate the three key parameters of ultrasonic frequency, material properties, and radial resultant force, accurately calculate the amplitude matching frequency, realize the traceability and adjustability of parameters, improve the versatility and accuracy of amplitude matching frequency, provide a reliable basis for determining subsequent feed parameters, and further improve the processing quality and efficiency of mold ejector pins.

[0065] S400 determines the feed speed and feed rate of the mold ejector pin based on the frequency matching the amplitude of the ejector pin.

[0066] It can be understood that the feed speed refers to the rotational speed of the mold ejector pin around its own axis, measured in revolutions per minute (r / min). The feed speed determines the circumferential speed of the ejector pin. For example, if the amplitude matching frequency is 17.000345kHz, the feed speed can be determined to be 1200r / min. The feed rate refers to the speed at which the ejector pin moves axially, measured in millimeters per minute (mm / min). It determines the processing efficiency and surface quality. For example, combined with a feed speed of 1200r / min, the feed rate can be determined to be 50mm / min. Both feed speed and feed rate must be compatible with the amplitude matching frequency. If the feed speed and feed rate do not match the amplitude matching frequency, it will lead to problems such as texture and dimensional deviations on the surface of the ejector pin.

[0067] As an optional embodiment of this application, S400, determining the feed rotation speed and feed rate of the mold ejector pin based on the amplitude matching frequency of the mold ejector pin includes: S410, based on the amplitude matching frequency and the preset speed-frequency ratio coefficient, obtains the feed speed of the mold ejector pin. The speed-frequency ratio coefficient is adapted according to the diameter of the rolling head. The diameter of the rolling head represents the straight-line distance between the first rolling head and the second rolling head.

[0068] It can be understood that the speed-frequency ratio coefficient is a proportional parameter connecting the amplitude matching frequency and the feed speed, and it has no unit. For example, if the diameter of the rolling head is 10mm and the preset speed-frequency ratio coefficient is 60 (r / min) / kHz, when the amplitude matching frequency is 17.000345kHz, the feed speed = 17.000345kHz × 60 (r / min) / kHz ≈ 1020r / min. The diameter of the rolling head refers to the straight-line distance between the first and second rolling heads arranged symmetrically, and the unit is millimeters (mm). For example, if the first and second rolling heads are symmetrically arranged on both sides of the ejector pin, and the line connecting their centers passes through the ejector pin axis, the straight-line distance is 10mm, which is the diameter of the rolling head. The size of the rolling head diameter directly affects the contact area and force distribution between the rolling head and the ejector pin.

[0069] In one possible implementation, S410, based on the amplitude matching frequency and a preset rotational speed to frequency ratio coefficient, obtains the feed speed of the mold ejector pin, including: S411, the ratio coefficient of rotational speed and frequency is determined in advance based on the diameter of the rolling head. The diameter of the rolling head is the straight-line distance between the first rolling head and the second rolling head arranged symmetrically. The larger the diameter of the rolling head, the smaller the value of the ratio coefficient of rotational speed and frequency.

[0070] This is understandable. For example, when the diameter of the rolling head is 8mm, the contact area between the rolling head and the ejector pin is small, requiring a higher feed speed to match the vibration frequency. Therefore, the speed-to-frequency ratio is set to 70 (r / min) / kHz. When the diameter of the rolling head increases to 12mm, the contact area increases. If the speed is too high, it will cause the ejector pin surface to overheat and wear to increase. Therefore, the ratio is adjusted to 50 (r / min) / kHz, which conforms to the rule that "the larger the diameter of the rolling head, the smaller the ratio." By setting the ratio in advance according to the diameter of the rolling head, the feed speed can be matched with the working conditions of the rolling head, avoiding processing defects caused by an unreasonable ratio.

[0071] S412, the amplitude matching frequency is coupled with the rotation speed and frequency proportionality coefficient to obtain the feed speed of the mold ejector pin.

[0072] It can be understood that coupling calculation refers to the coordinated calculation of amplitude matching frequency and proportional coefficient, so that the calculation result is adapted to both frequency and rolling head working condition. For example, based on the previous text, the rolling head diameter is 10mm, the proportional coefficient is 60 (r / min) / kHz, and the amplitude matching frequency is 17.000345kHz. The coupling calculation method is "feed speed = amplitude matching frequency × speed and frequency proportional coefficient", that is, 17.000345×60≈1020r / min. If the amplitude matching frequency increases to 17.5kHz, and the proportional coefficient remains unchanged, then the feed speed = 17.5×60=1050r / min, so that the feed speed is adjusted synchronously with the amplitude matching frequency to adapt to the pin vibration state.

[0073] By adopting the above steps S411 to S412, the feed speed can be adapted to both the amplitude matching frequency and the diameter of the rolling head, which improves the accuracy and real-time performance of the speed. The feed speed can be dynamically adjusted according to the change of the amplitude matching frequency, thereby improving the stability of the machining process.

[0074] S420 obtains the feed speed of the mold ejector pin based on the preset rolling trajectory overlap rate, feed speed and rolling head diameter.

[0075] It can be understood that the preset rolling trajectory overlap rate refers to the overlap ratio of two adjacent rolling trajectories, expressed as a percentage (%). The size of the preset rolling trajectory overlap rate determines the surface smoothness of the ejector pin. For example, a preset rolling trajectory overlap rate of 50% means that the subsequent rolling trajectory covers 50% of the previous trajectory. The higher the overlap rate, the smoother the surface, but the lower the processing efficiency. Combining the parameters mentioned above, such as a preset overlap rate of 50%, a feed speed of 1020 r / min, and a rolling head diameter of 10 mm, the feed speed can be calculated using a formula to ensure that the feed speed is matched with the rolling trajectory, speed, and rolling head size.

[0076] In one possible implementation, S420, based on the preset rolling trajectory overlap ratio, feed speed, and rolling head diameter, obtains the feed speed of the mold ejector pin, including: S421, based on the feed speed and the diameter of the rolling head, the rolling head speed is obtained.

[0077] It can be understood that the rolling head speed refers to the rotational speed of the rolling head around its own axis, measured in r / min. The rolling head speed is related to the ejector feed speed and the rolling head diameter. For example, if the feed speed is 1020 r / min and the rolling head diameter is 10 mm, the rolling head speed can be calculated using the formula (rolling head speed = feed speed × rolling head diameter ÷ ejector diameter). If the ejector diameter is 8 mm, then the rolling head speed = 1020 × 10 ÷ 8 = 1275 r / min. The rolling head speed directly affects the contact pressure between the rolling head and the ejector and the processing efficiency, and must be matched with the feed speed and the rolling head diameter.

[0078] S422, based on the rolling head rotation speed and the preset rolling trajectory overlap rate threshold, the feed speed of the mold ejector pin is obtained.

[0079] It can be understood that the overlap rate threshold of the rolling trajectory refers to the preset upper limit or standard value of the overlap rate. For example, if the preset overlap rate threshold is 50%, combined with the rolling head speed of 1275 r / min and the rolling head diameter of 10 mm, the feed rate can be calculated using the formula (feed speed = rolling head speed × rolling head diameter × (1 - overlap rate threshold)) to obtain the feed rate = 1275 × 10 × (1 - 50%) = 6375 mm / min. If the overlap rate threshold is adjusted to 60%, the feed rate = 1275 × 10 × 40% = 5100 mm / min. This shows that the higher the overlap rate, the lower the feed rate, which improves the flatness of the machined surface.

[0080] By adopting the above steps S421 to S422, it is helpful to bind the feed rate with the rolling head rotation speed, rolling head diameter, and overlap depth, so that the feed rate can meet the processing efficiency requirements and ensure the processing quality of the ejector pin surface, thereby improving the processing flexibility and reliability.

[0081] By adopting the above steps S410 to S420, it is helpful to achieve precise matching between the feed speed and feed rate and the amplitude matching frequency. At the same time, combined with working parameters such as the diameter of the rolling head and the overlap rate of the rolling trajectory, the rotational speed and axial movement speed of the ejector pin during machining are coordinated and reasonable; thus improving the machining consistency and pass rate of the mold ejector pin and reducing the machining cost.

[0082] S500 determines the grain refinement parameters of the mold ejector pin based on the feed rotation speed, feed speed, amplitude matching frequency, ultrasonic frequency, and static pressure.

[0083] It is understandable that grain refinement parameters are key parameters used to control the grain size of the material during the machining of mold ejector pins. These include grain refinement temperature, refinement time, and refinement pressure. The core function of grain refinement parameters is to make the grains of the ejector pin material smaller and more uniform by adjusting these parameters, thereby improving the hardness, toughness, and wear resistance of the ejector pin. For example, combining all the operating parameters mentioned above (feed speed 1020 r / min, feed rate 6375 mm / min, amplitude matching frequency 17.000345 kHz, ultrasonic frequency 20 kHz) z. Static pressure 150N / 145N), the grain refinement parameters can be determined as follows: refinement temperature 850℃, refinement time 20min, refinement pressure 120N; grain refinement is a key step in ejector pin processing. Unrefined ejector pins have coarse grains, which are prone to breakage and wear. After refinement, the service life and performance of the ejector pin can be significantly improved. For example, after grain refinement, the hardness of SKD61 material ejector pins can be increased from HRC50 to over HRC55, and the toughness can be increased by 30%, effectively preventing the ejector pin from breaking during the ejection process of the mold.

[0084] It should be understood that the sequence number of each step in the above embodiments does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0085] Corresponding to the ultrasonic-assisted rolling surface grain refinement method for mold ejector pins described in the above embodiments, this application also provides an ultrasonic-assisted rolling surface grain refinement device for mold ejector pins. Each unit of the device can realize each step of the ultrasonic-assisted rolling surface grain refinement method for mold ejector pins. Figure 4 The diagram shows a structural block diagram of the ultrasonic-assisted rolling surface grain refinement device for mold ejector pins provided in the embodiments of this application. For ease of explanation, only the parts related to the embodiments of this application are shown.

[0086] Reference Figure 4 The device includes: The acquisition unit is used to acquire the ultrasonic frequency and static pressure of the mold ejector pin. The static pressure includes a first directional force and a second directional force. The first directional force and the second directional force are applied by a first rolling head and a second rolling head symmetrically arranged on both sides of the mold ejector pin, respectively, to counteract radial bending loads.

[0087] The resultant force unit is used to determine the radial resultant force of the mold ejector pin based on the first and second directional forces. The radial resultant force reflects the force exerted on the mold ejector pin during bending deformation.

[0088] An amplitude unit is used to obtain the amplitude matching frequency of the mold ejector pin based on the radial resultant force and ultrasonic frequency. The amplitude matching frequency is positively correlated with the radial resultant force.

[0089] The feed unit is used to determine the feed rotation speed and feed rate of the mold ejector pin based on the frequency matching the amplitude of the mold ejector pin.

[0090] The grain refinement unit is used to determine the grain refinement parameters of the mold ejector pin based on the feed speed, feed rate, amplitude matching frequency, ultrasonic frequency, and static pressure of the mold ejector pin.

[0091] It should be noted that the information interaction and execution process between the above-mentioned units are based on the same concept as the method embodiments of this application. For details on their specific functions and technical effects, please refer to the method embodiments section, which will not be repeated here.

[0092] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the above-described division of functional units is used as an example. In practical applications, the above functions can be assigned to different functional units as needed, that is, the internal structure of the device can be divided into different functional units to complete all or part of the functions described above. The functional units in the embodiments can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit. Furthermore, the specific names of the functional units are only for easy differentiation and are not intended to limit the scope of protection of this application. The specific working process of the units in the above device can be referred to the corresponding process in the foregoing method embodiments, and will not be repeated here.

[0093] This application also provides a double-sided rolling device. Figure 5 This is a schematic diagram of the structure of a double-sided rolling device provided in an embodiment of this application. Figure 5 As shown, the double-sided rolling device 6 of this embodiment includes: at least one processor 60 ( Figure 5 Only one is shown in the image), at least one memory 61 ( Figure 5 (Only one is shown in the image) and a computer program 62 stored in the at least one memory 61 and executable on the at least one processor 60, wherein when the processor 60 executes the computer program 62, it causes the double-sided rolling device 6 to perform the steps in the embodiments of the ultrasonic-assisted rolling surface grain refinement method for any of the above-described mold ejector pins, or causes the double-sided rolling device 6 to perform the functions of the units in the above-described device embodiments.

[0094] For example, the computer program 62 may be divided into one or more units, which are stored in the memory 61 and executed by the processor 60 to complete this application. The one or more units may be a series of computer program instruction segments capable of performing a specific function, which describe the execution process of the computer program 62 in the double-sided rolling device 6.

[0095] The double-sided rolling device 6 can be a cloud server, cloud host, commercial desktop computer, laptop computer, e-commerce dedicated smart terminal, tablet computer, etc. The double-sided rolling device includes a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements the method as described in any of the foregoing aspects. The double-sided rolling device 6 may include, but is not limited to, a processor 60 and a memory 61. Those skilled in the art will understand that... Figure 5 This is merely an example of the double-sided rolling device 6 and does not constitute a limitation on the double-sided rolling device 6. It may include more or fewer components than shown, or combine certain components, or different components, such as input / output devices, network access devices, buses, etc.

[0096] The processor 60 can be a Central Processing Unit (CPU), or it can be other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor can be a microprocessor or any conventional processor.

[0097] In some embodiments, the memory 61 may be an internal storage unit of the double-sided rolling device 6, such as a hard disk or memory of the double-sided rolling device 6. In other embodiments, the memory 61 may be an external storage device of the double-sided rolling device 6, such as a plug-in hard disk, SmartMedia Card (SMC), Secure Digital (SD) card, or Flash Card equipped on the double-sided rolling device 6. Further, the memory 61 may include both internal storage units and external storage devices of the double-sided rolling device 6. The memory 61 is used to store operating systems, applications, bootloaders, data, and other programs, such as the program code of computer programs. The memory 61 can also be used to temporarily store data that has been output or will be output.

[0098] This application also provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the steps in any of the above method embodiments.

[0099] This application provides a computer program product that, when run on a double-sided rolling mill, enables the double-sided rolling mill to perform the steps described in any of the above method embodiments.

[0100] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, all or part of the processes in the methods of the above embodiments of this application can be implemented by a computer program instructing related hardware. The computer program can be stored in a computer-readable storage medium, and when executed by a processor, it can implement the steps of the various method embodiments described above. The computer program includes computer program code, which can be in the form of source code, object code, executable files, or certain intermediate forms. The computer-readable medium can include at least: any entity or system capable of carrying computer program code to a double-sided rolling device, a recording medium, a computer memory, a read-only memory (ROM), a random access memory (RAM), an electrical carrier signal, a telecommunication signal, and a software distribution medium. Examples include USB flash drives, portable hard drives, magnetic disks, or optical disks.

[0101] In the above embodiments, the descriptions of each embodiment have different focuses. For parts that are not described in detail or recorded in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0102] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0103] In the embodiments provided in this application, it should be understood that the disclosed ultrasonic-assisted rolling surface grain refinement method, ultrasonic-assisted rolling surface grain refinement device, and double-sided rolling equipment for mold ejector pins can be implemented in other ways. For example, the embodiments of the ultrasonic-assisted rolling surface grain refinement device and double-sided rolling equipment for mold ejector pins described above are merely illustrative. For instance, the division of units is merely a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another device, or some features may be ignored or not executed. Furthermore, the displayed or discussed mutual coupling, direct coupling, or communication connection may be through some interfaces; the indirect coupling or communication connection between units may be electrical, mechanical, or other forms.

[0104] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0105] The above-described embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of this application.

Claims

1. A method for refining the surface grains of a mold ejector pin using ultrasonic-assisted rolling, characterized in that, The method, applied to a double-sided rolling mill, wherein the double-sided rolling mill includes a first rolling head and a second rolling head, comprises: The ultrasonic frequency and static pressure of the mold ejector pin are obtained; wherein, the static pressure includes a first directional force and a second directional force; the first directional force and the second directional force are respectively applied by the first rolling head and the second rolling head symmetrically arranged on both sides of the mold ejector pin, to counteract radial bending load; Based on the first directional force and the second directional force of the mold ejector pin, the radial resultant force of the mold ejector pin is determined; wherein, the radial resultant force reflects the force exerted on the mold ejector pin during bending deformation; Based on the radial resultant force of the mold ejector pin and the ultrasonic frequency, the amplitude matching frequency of the mold ejector pin is obtained; wherein, the amplitude matching frequency is positively correlated with the radial resultant force; The feed rotation speed and feed rate of the mold ejector pin are determined based on the amplitude matching frequency of the mold ejector pin. The grain refinement parameters of the mold ejector pin are determined based on the feed rotation speed, feed speed, amplitude matching frequency, ultrasonic frequency, and static pressure of the mold ejector pin.

2. The method for refining the surface grains of a mold ejector pin by ultrasonic-assisted rolling according to claim 1, characterized in that, Determining the radial resultant force of the mold ejector pin based on the first directional force and the second directional force of the mold ejector pin includes: Based on the first directional force and the first directional coefficient, the first radial force is obtained; The second radial force is obtained based on the second directional force and the second directional coefficient; wherein the first directional coefficient and the second directional coefficient are obtained according to the installation accuracy of the rolling head; The radial resultant force of the mold ejector pin is obtained based on the first radial force and the second radial force.

3. The method for refining the surface grains of a mold ejector pin by ultrasonic-assisted rolling according to claim 2, characterized in that, The step of obtaining the radial resultant force of the mold ejector pin based on the first radial force and the second radial force includes: The directional characteristics of the mold ejector pin are determined based on the first radial force and the second radial force; Based on the directional characteristics, the sum of the first radial force and the second radial force is calculated to obtain the radial resultant force of the mold ejector pin.

4. The method for refining the surface grains of a mold ejector pin by ultrasonic-assisted rolling according to claim 3, characterized in that, The step of calculating the sum of the first radial force and the second radial force based on the directional characteristics to obtain the radial resultant force of the mold ejector pin includes: Based on the aforementioned directional characteristics, the first radial force and the second radial force are assigned directional values. The first radial force pointing towards the center of the ejector pin is recorded as a positive value, and the second radial force moving away from the center of the ejector pin is recorded as a negative value. The radial resultant force of the mold ejector pin is obtained based on the positive value of the first radial force and the negative value of the second radial force.

5. The method for refining the surface grains of a mold ejector pin by ultrasonic-assisted rolling according to claim 1, characterized in that, The method of obtaining the amplitude matching frequency of the mold ejector pin based on the radial resultant force and the ultrasonic frequency includes: Based on the ultrasonic frequency, the material correlation coefficient of the mold ejector pin is obtained; The amplitude matching frequency of the mold ejector pin is obtained based on the radial resultant force of the ejector pin, the ultrasonic frequency, and the material correlation coefficient.

6. The method for refining the surface grains of a mold ejector pin by ultrasonic-assisted rolling according to claim 5, characterized in that, The process of obtaining the material correlation coefficient of the mold ejector pin based on the ultrasonic frequency includes: Obtain the material feature template for each of the mold ejector pins; Based on the ultrasonic frequency, feature extraction is performed to obtain the frequency feature data of the ultrasonic frequency. The material correlation coefficient is obtained based on the material feature template and the frequency feature data.

7. The method for refining the surface grains of a mold ejector pin by ultrasonic-assisted rolling according to claim 5, characterized in that, The method of obtaining the amplitude matching frequency of the mold ejector pin based on the radial resultant force of the ejector pin, the ultrasonic frequency, and the material correlation coefficient includes: Based on the material correlation coefficient and the ultrasonic frequency, the fundamental frequency of the mold ejector pin amplitude is obtained; The amplitude matching frequency of the mold ejector pin is obtained by finely adjusting the basic frequency of the amplitude of the mold ejector pin according to the radial resultant force.

8. The method for refining the surface grains of a mold ejector pin by ultrasonic-assisted rolling according to claim 1, characterized in that, The step of determining the feed rotation speed and feed rate of the mold ejector pin based on the amplitude matching frequency of the mold ejector pin includes: Based on the amplitude matching frequency and the preset rotation speed to frequency ratio coefficient, the feed speed of the mold ejector pin is obtained; wherein, the rotation speed to frequency ratio coefficient is adapted according to the diameter of the rolling head; the diameter of the rolling head represents the straight-line distance from the first rolling head to the second rolling head; The feed speed of the mold ejector pin is obtained based on the preset rolling trajectory overlap rate, the feed speed and the diameter of the rolling head.

9. The method for refining the surface grains of a mold ejector pin by ultrasonic-assisted rolling according to claim 8, characterized in that, The step of obtaining the feed speed of the mold ejector pin based on the amplitude matching frequency and the preset rotation speed to frequency ratio coefficient includes: The rotational speed and frequency ratio coefficient is determined in advance based on the diameter of the rolling head; wherein, the diameter of the rolling head is the straight-line distance between the first rolling head and the second rolling head arranged symmetrically, and the larger the diameter of the rolling head, the smaller the value of the rotational speed and frequency ratio coefficient; The feed speed of the mold ejector pin is obtained by coupling the amplitude matching frequency with the rotation speed and the frequency proportionality coefficient.

10. The method for refining the surface grains of a mold ejector pin by ultrasonic-assisted rolling according to claim 8, characterized in that, The step of obtaining the feed speed of the mold ejector pin based on the preset overlap rate threshold of the rolling trajectory, the feed speed, and the diameter of the rolling head includes: The rolling head rotation speed is obtained based on the feed speed and the rolling head diameter; The feed speed of the mold ejector pin is obtained based on the rotation speed of the rolling head and the preset overlap rate threshold of the rolling trajectory.

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