CN116252447A - Gear injection molding regulation and control method - Google Patents

Abstract

The embodiment of the invention provides a gear injection molding regulation and control method, which comprises the steps of obtaining a test parameter table of injection molding of a target gear; performing a simulation test according to the test parameter table to obtain a simulation result; determining global optimal technological parameters according to the simulation result; performing injection molding test under the obtained global optimal technological parameters, and performing injection molding to obtain a gear sample; determining the gear molding shrinkage rate according to the gear sample measurement data; determining a size parameter of an inversion cavity of the gear die according to the gear molding shrinkage rate; determining the size of a gear cavity according to the inversion cavity size parameter of the gear mold, and performing precision machining according to the size of the gear cavity to obtain a target gear injection mold; and carrying out injection molding on the target gear according to the target gear injection mold to obtain a target gear finished product. The injection molding precision of the small modulus gear is improved, and the large-scale production and manufacturing of the high-precision small modulus gear are facilitated.

Description

Gear injection molding control method

technical field

The invention relates to the fields of advanced machinery manufacturing and material molding, in particular to a gear injection molding control method.

Background technique

The main processing method of small modulus gears is injection molding. During injection molding, plastic small modulus gears undergo three steps: heating and melting of engineering plastics, flow molding of liquid plastics, and cooling and solidification in the cavity of the mold. During this process, due to the physical properties of plastics that expand with heat and contract with cold, the plastic gear will shrink violently when it is taken out of the mold, which causes the actual gear size parameters and tooth profile shape to be different from the design. And when the involute tooth shape is poured, the mold cavity has a nonlinear shrinkage problem due to the different local temperature of the mold and the different flow direction and speed of the pouring liquid during the pouring process, resulting in different local shrinkage.

At the same time, a single process optimization is relatively small for shrinkage control, so it is necessary to carry out cavity inversion design, and reversely expand the gear cavity to compensate for shrinkage. Traditional inversion methods mainly fall into the following two categories. Huang Tianshi positively shifted the tooth profile curve to obtain the tooth shape curve of ^the cavity; Li Jianxin corrected the modulus and pressure angle of the tooth shape of the cavity. Angle is corrected to

'

cosα = cosα(1s). Although the above two inverse design methods can improve the tooth profile accuracy of plastic small modulus gears to a certain extent, considering that the polymer shrinkage rate is affected by various factors such as material properties, production environment, process parameters and mold structure, it is difficult to rely on a single The shrinkage rate of the material cannot truly reflect the degree of shrinkage of the gear, and it is necessary to carry out parametric inversion design of the mold cavity in combination with the shrinkage characteristics of the gear and the actual molding shrinkage rate.

Contents of the invention

An embodiment of the present invention provides a gear injection molding control method, which aims to solve the problem that the existing inversion cavity design method does not consider the huge deviation between the material shrinkage rate and the actual molding shrinkage rate. Through the detection of the shrinkage rate of the key dimension of the actual molding of the small modulus gear, the parametric design of the inversion cavity of the small modulus gear can be carried out, which can reduce the number of trial molds, avoid the waste of time and cost, and at the same time make the small The inversion design of the modulus gear becomes simpler and more accurate, which can avoid the problem of inaccurate inversion design of the small modulus gear, greatly improves the injection molding accuracy of the small modulus gear, and is beneficial to the high-precision small modulus gear. Mass production.

In the first aspect, an embodiment of the present invention provides a gear injection molding control method, the method comprising:

Obtain the test parameter table for the injection molding of the target gear;

Carry out simulation test according to described test parameter table, obtain simulation result;

According to the simulation result, determine the global optimum process parameter;

Carry out an injection molding test under the obtained global optimal process parameters, and obtain a gear sample by injection molding;

determining the gear molding shrinkage rate according to the gear sample measurement data;

According to the gear molding shrinkage rate, determine the gear mold inversion cavity size parameter;

Inverting the cavity size parameters according to the gear mold, determining the gear cavity size, and performing precision machining according to the gear cavity size, to obtain the target gear injection mold;

According to the target gear injection mold, the target gear is injection-molded to obtain the target gear finished product.

Optionally, the acquisition of a test parameter table for injection molding of the target gear includes:

Obtain the test input parameters of the target gear;

Determine the range of process parameters according to the target gear material properties;

A test parameter table for injection molding of the target gear is determined according to the test input parameters and the process parameter range.

Optionally, the simulation test is carried out according to the test parameter table to obtain simulation results, including:

According to the actual forming situation, establish the simulation model of the target gear;

After selecting the analysis type and analysis sequence, the simulation test is carried out according to the test parameter table, and the simulation result is obtained.

Optionally, the determining the globally optimal process parameters according to the simulation results includes:

According to the simulation results, determine the maximum shrinkage and volumetric shrinkage;

Through the simulation results, determine the addendum circle diameter and the dedendum circle diameter of the target gear simulation model;

According to the addendum circle diameter and the dedendum circle diameter, determine the addendum circle diameter shrinkage rate and the dedendum circle diameter shrinkage rate;

Taking the maximum shrinkage, the volumetric shrinkage, the addendum circle diameter shrinkage and the dedendum root circle diameter shrinkage as response targets, and taking the minimum response target as the optimization target to determine the global optimal process parameters .

Optionally, the determining the global final process parameter with the minimum response target as the optimization target includes:

Determining a response surface model between process parameters and said response target;

Taking the minimum of the response target as the optimization target, the response surface model is optimized to obtain the global final process parameters.

Optionally, the injection molding test is carried out under the obtained global optimal process parameters, and the gear samples are obtained by injection molding, including:

Determine the initial gear cavity according to the target gear size;

According to the initial gear cavity, the initial mold cavity is precisely processed to obtain an initial injection mold;

Through the initial injection mold, a gear sample is obtained by injection molding.

Optionally, the determining the gear molding shrinkage rate according to the gear sample measurement data includes:

After the gear sample is stabilized, determining the dimensions of the gear sample;

From the dimensions of the gear sample, determine the gear molding shrinkage.

Optionally, the determination of the gear molding shrinkage rate according to the size of the gear sample includes:

calculating an average dedendum circle diameter for a plurality of said gear samples;

Based on the average dedendum circle diameter, the gear molding shrinkage rate is calculated.

Optionally, the determination of gear mold inversion cavity size parameters according to the gear molding shrinkage ratio includes:

According to the modulus of the target gear and the shrinkage ratio of the gear, determine the size parameter of the inversion cavity of the gear mold.

Optionally, the precision machining is carried out according to the size of the gear cavity to obtain the target gear injection mold, including:

Keeping the overall structure of the mold, the cooling system, the temperature control system and the pouring system unchanged, the mold cavity is precisely processed according to the size of the gear cavity to obtain the target gear injection mold.

In the embodiment of the present invention, the test parameter table of the injection molding of the target gear is obtained; the simulation test is carried out according to the test parameter table, and the simulation result is obtained; according to the simulation result, the global optimal process parameter is determined; Carry out injection molding test under optimal process parameters, and obtain gear samples by injection molding; determine the gear molding shrinkage rate according to the gear sample measurement data; determine the gear mold inversion cavity size parameters according to the gear molding shrinkage rate; according to the gear mold Invert the cavity size parameters to determine the gear cavity size, and perform precision machining according to the gear cavity size to obtain the target gear injection mold; according to the target gear injection mold, injection mold the target gear to obtain the target gear finished product. Through the detection of the shrinkage rate of the key dimension of the actual molding of the small modulus gear, the parametric design of the inversion cavity of the small modulus gear can be carried out, which can reduce the number of trial molds, avoid the waste of time and cost, and at the same time make the small The inversion design of the modulus gear becomes simpler and more accurate, which can avoid the problem of inaccurate inversion design of the small modulus gear, greatly improves the injection molding accuracy of the small modulus gear, and is conducive to the large-scale production of high-precision small modulus gears. Manufacturing at scale.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only These are some embodiments of the present invention. Those skilled in the art can also obtain other drawings based on these drawings without creative work.

Fig. 1 is a flow chart of a gear injection molding control method provided by an embodiment of the present invention.

Detailed ways

The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some, not all, embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without creative efforts fall within the protection scope of the present invention.

Please refer to FIG. 1. FIG. 1 is a flowchart of a gear injection molding control method provided by an embodiment of the present invention. As shown in FIG. 1, the gear injection molding control method includes the following steps:

101. Obtain a test parameter table for injection molding of the target gear.

In the embodiment of the present invention, the above-mentioned target gear may be a plastic small module gear, which is the most commonly used transmission part of MEMS, and has significant advantages such as small weight, low cost, self-lubrication, transmission noise, and strong ability to absorb shock and vibration. , are widely used in cutting-edge fields such as aerospace, 5G communication and medical equipment.

Optionally, obtaining the test parameter table for the injection molding of the target gear includes: obtaining the test input parameters of the target gear; determining the process parameter range according to the above target gear material properties; determining the above Table of test parameters for injection molding of target gears.

In the embodiment of the present invention, the above-mentioned test input parameters may be mold temperature, melt temperature, holding pressure, holding time, injection speed and cooling time. Mold temperature is the main influencing factor in injection molding. If the mold temperature is too low, the strength of the part will decrease, the surface quality will be poor, the internal stress will increase, it will be difficult to demould, and even the part will be short of material (not full of injection), etc.; If it is too high, the parts are easily deformed, and the production cycle is also prolonged. The melt temperature directly affects the properties of the melt. The holding pressure means that the screw does not retreat immediately after injection molding, but continues to exert pressure on the front melt, and the holding pressure is less than or equal to the injection pressure. The holding time refers to the time that the material is kept under a certain pressure after filling the cavity during injection molding. Injection speed means that by determining the beginning, middle, and end of the filling speed segment, and realizing a smooth transition from one set point to another set point, a stable melt surface speed can be guaranteed to produce the desired molecule and the minimum internal stress. Cooling time refers to the long cooling time of injection molding. Long cooling time will affect the production cost, and short cooling time will easily cause deformation and affect the yield.

The aforementioned target gear material properties refer to its properties such as density, processing temperature, average specific heat, mold temperature, and shrinkage rate.

Specifically, the appropriate process parameter range is selected according to the material properties, and the Box-Behnken test design is carried out using ISIGHT software to obtain the corresponding test parameter table. The above-mentioned ISIGHT was first proposed and developed by Dr. Siu S.Tong of MIT around the 1980s. After these years of development, it has become a leader in similar software; ISIGHT itself does not perform calculations, but it passes The corresponding method calls other software (such as ABAQUS, ANSYS, etc.) for calculation, so ISIGHT is first of all a "software robot", which can continuously call the corresponding engineering calculation software for calculation without manual intervention. A Box-Behnken experimental design is a type of response surface design that does not contain embedded factors or fractional factorial designs. Box-Behnken designs have treatment combinations at center points at the edges of the experimental space and require at least three factors.

In the embodiment of the present invention, the above test parameter table may refer to mold temperature parameters, melt temperature parameters, holding pressure parameters, holding pressure time parameters, injection molding speed parameters and cooling time parameters.

102. Carry out the simulation test according to the test parameter table, and obtain the simulation result.

In the embodiment of the present invention, the above-mentioned simulation experiment is to use Moldflow simulation software to simulate the real effect on the computer. The Moldflow simulation software links the theoretical conditions and the experimental process through a graphical interface, and uses certain programming to achieve the simulated real effect.

Optionally, the above-mentioned simulation test is carried out according to the above-mentioned test parameter table to obtain the simulation results, including: establishing the above-mentioned target gear simulation model according to the actual molding situation; after selecting the analysis type and analysis sequence, performing the simulation test according to the above-mentioned test parameter table to obtain Simulation results.

In the embodiment of the present invention, the above-mentioned gear cavity, pouring system, and cooling system are included according to the actual molding conditions, and a small-modulus gear simulation model is established. The above-mentioned analysis type is injection molding of thermoplastic composite materials, and the above-mentioned analysis sequence is cooling + filling + preservation. Compression + warping, according to the test parameter table, the simulation test is carried out, and the simulation result is obtained. The gear cavity is a non-standard internal gear. The outer circle and thickness of the gear cavity blank have been finished, and can be directly used as the installation and measurement benchmark of the cavity. The gating system is usually composed of four parts: the sprue, the runner (main channel and the runner), and the gate to the cold slug well. It refers to the channel system that guides the plastic melt from the nozzle of the injection machine to the cavity. The cooling system is mainly used to cool the oil temperature. Excessive oil temperature will cause various failures, so the oil temperature must be controlled.

In the embodiment of the present invention, the above-mentioned thermoplastic composite material is a general term for various thermoplastic resins reinforced with glass fiber, carbon fiber, aramid fiber, etc., and is called FRTP (Fiber Rinforced Thermo Plastics) abroad. Due to the different types of thermoplastic resins and reinforcing materials, the production process and the performance of the composite materials are very different. The density of thermoplastic composite material is 1.1-1.6g/cm3, which is only 1/5-1/7 of steel, and 1/3-1/4 lighter than thermosetting FRP. It can obtain higher mechanical strength with a smaller unit mass. The physical properties, chemical properties, and mechanical properties of thermoplastic composite materials are all designed through reasonable selection of raw material types, proportions, processing methods, fiber content, and layering methods.

Specifically, the injection molding process of thermoplastic composite materials has a short molding period, minimum energy consumption, high product precision, complex switches and products with inserts can be formed at one time, and several products can be produced in one mold, with high production efficiency.

In the embodiment of the present invention, the aforementioned cooling+filling+holding+warping refers to the gear injection molding process. Cooling accounts for about 70% to 80% of the cooling time in injection molding. Therefore, the cooling time will directly affect the length of the molding cycle and output of plastic products. In the demoulding stage, the temperature of the plastic product should be cooled to a temperature lower than the thermal deformation temperature of the plastic product to prevent the relaxation of the plastic product due to residual stress or the warping and deformation caused by the external force of the demoulding. Filling is the first step in the injection molding cycle, from the time the mold closes to start the injection until the mold cavity is filled to about 95%. Holding pressure is the most important stage that affects the performance of the final product in the injection molding process. Since the polymer melt expands when heated and then shrinks when cooled, it will inevitably lead to uneven distribution of product internal density and profit. Therefore, it is necessary to choose a suitable holding pressure . The packing stage is a non-isothermal and compressible complex stage. Warping means that the plastic part is not formed according to the designed shape, but the surface is twisted. The warping of the plastic part is caused by the uneven shrinkage of the formed plastic part. If the entire plastic part has a uniform shrinkage rate, the deformation of the plastic part will not warp However, due to the interaction of many factors such as molecular chain/fiber orientation, mold cooling, plastic part design, mold design and forming conditions, it is very complicated to achieve low shrinkage or uniform shrinkage work.

103. According to the simulation results, determine the global optimal process parameters.

In the embodiment of the present invention, the above global optimal process parameters may be the optimal temperature of the mold temperature, the optimal temperature of the melt temperature, the optimal pressure of the holding pressure, the optimal time of the holding time, the optimal speed of the injection molding speed and the cooling time optimal time.

Optionally, the above-mentioned determination of the global optimal process parameters according to the simulation results includes: determining the maximum shrinkage amount and volume shrinkage rate according to the above simulation results; determining the addendum circle diameter of the above-mentioned target gear simulation model through the above simulation results and the diameter of the dedendum circle; according to the diameter of the above-mentioned addendum circle and the above-mentioned diameter of the dedendum circle, determine the shrinkage rate of the addendum circle diameter and the shrinkage rate of the dedendum circle diameter; The diameter shrinkage rate and the above-mentioned dedendum circle diameter shrinkage rate are used as the response target, and the minimum of the above-mentioned response target is the optimization target to determine the global final process parameters.

In the embodiment of the present invention, the above-mentioned maximum shrinkage refers to the physical properties of plastics that expand with heat and contract with cold. Plastic gears will undergo severe shrinkage when they are taken out of the mold. The percent increase in local density at the reference temperature (default 25°C/77°F). The local shrinkage, critical dimension shrinkage and overall shrinkage of gears will directly affect the forming accuracy of small modulus gears. Therefore, the maximum shrinkage (Y ₁ ), the shrinkage rate of the addendum circle diameter (Y ₃ ), the shrinkage rate of the root circle diameter (Y ₃ ) and the volume shrinkage rate (Y ₄ ) are selected as the response target (Y), and the maximum shrinkage amount Y ₁ and volume shrinkage Y ₄ can be obtained directly from the simulation results.

和齿根圆直径/>

然后齿顶圆直径收缩率/>

齿根圆直径收缩率/>

Then derive the gear shrinkage model from the simulation results at a ratio of 1:1, and then use CAD 3D modeling software to measure the addendum circle diameter of the gear shrinkage model

and root circle diameter/>

Then addendum diameter shrinkage ratio />

Root diameter shrinkage ratio/>

Import the test results into the Isight software, and establish a second-order response surface model between the process parameters and the response target through the Approximation Models module. By adjusting the structure of the model, the accuracy of the model can be ensured to reach more than 90%.

The above-mentioned ISIGHT was first proposed and developed by Dr. Siu S.Tong of MIT around the 1980s. After these years of development, it has become a leader in similar software; ISIGHT itself does not perform calculations, but it passes The corresponding method calls other software (such as ABAQUS, ANSYS, etc.) for calculation, so ISIGHT is first of all a "software robot", which can continuously call the corresponding engineering calculation software for calculation without manual intervention. The above-mentioned Approximation Models module is an approximation model. In order to reduce the complexity of the problem and reduce the amount of calculation, it is necessary to adopt a certain approximate modeling method.

Optionally, taking the above-mentioned minimum response target as the optimization target, determining the global final process parameters includes: determining the response surface model between the process parameters and the above-mentioned response target; taking the above-mentioned minimum response target as the optimization target, and determining the response surface The model is optimized to obtain the global final process parameters.

In the embodiment of the present invention, the local shrinkage, critical dimension shrinkage and overall shrinkage of the gear will directly affect the forming accuracy of the small modulus gear, so the maximum shrinkage amount (Y ₁ ), the shrinkage rate of the addendum circle diameter (Y ₃ ) , root circle diameter shrinkage rate (Y ₃ ) and volume shrinkage rate (Y ₄ ) are used as the response target (Y), and the maximum shrinkage amount Y ₁ and volume shrinkage rate Y ₄ can be obtained directly from the simulation results.

和齿根圆直径/>

然后齿顶圆直径收缩率/>

齿根圆直径收缩率/>

Then derive the gear shrinkage model from the simulation results at a ratio of 1:1, and then use CAD 3D modeling software to measure the addendum circle diameter of the gear shrinkage model

and root circle diameter/>

Then addendum diameter shrinkage ratio />

Root diameter shrinkage ratio/>

Import the test results into the Isight software, and establish a second-order response surface model between the process parameters and the response target through the Approximation Models module. By adjusting the structure of the model, the accuracy of the model can be ensured to reach more than 90%.

The established second-order response surface model is optimized through the Multi-Objective Optimization module. Multi-Objective Optimization is multi-objective optimization. The optimal solution of the objective function is obtained through a certain optimization algorithm. The algorithm is NSGA-Ⅱ algorithm, NSGA- The II algorithm was proposed by Srinivas and Deb on the basis of NSGA in 2000. It is superior to the NSGA algorithm: it uses a fast non-dominated sorting algorithm, and the computational complexity is greatly reduced compared with NSGA; The operator replaces the shared radius shareQ that needs to be specified, and is used as the winning standard in the peer comparison after quick sorting, so that the individuals in the quasi-Pareto domain can be extended to the entire Pareto domain, and evenly distributed, maintaining the diversity of the population ; Introduce the elite strategy, expand the sampling space, prevent the loss of the best individual, and improve the computing speed and robustness of the algorithm. In the algorithm settings, the Population side is set to 12, the Number ofGenerations is set to 20, and the number of samples is 240, which meets the requirements of the recommended value between 20 and 200. The crossover probability CrossoverRate is set to 0.9, and the recommended value is 0.6 to 1, and the rest are set by default, so that the global optimal process parameters that make the optimization index Y the smallest can be obtained.

104. Perform an injection molding test under the obtained global optimal process parameters, and obtain a gear sample by injection molding.

In the embodiment of the present invention, under the obtained global optimal process parameters, a precision injection molding machine is selected to carry out a small modulus gear injection molding test to obtain an injection molded gear sample.

Optionally, the above-mentioned injection molding test is carried out under the obtained global optimal process parameters, and the gear samples are obtained by injection molding, including: determining the initial gear cavity according to the target gear size; determining the initial mold cavity according to the initial gear cavity Precise machining is carried out to obtain the initial injection mold; through the initial injection mold, the gear sample is obtained by injection molding.

In the embodiment of the present invention, the above-mentioned initial gear cavity is designed according to the target gear size, and the mold cavity is precisely machined by using the wire cutting process, and finally, the super depth-of-field microscope is used to detect whether the gear mold size is within the error range. Since the polymer particles will absorb water vapor in the air, in order to avoid too much change in the density of the polymer particles, resulting in excessive fluctuations in the shrinkage of the material, after taking out the polymer particle material and weighing it, it is necessary to weigh the polymer material before molding. Sufficient drying is carried out until the weight data of the polymer material remains stable. Then select a precision injection molding machine for target gear molding to obtain injection molded gear samples.

In the embodiment of the present invention, the above-mentioned slow wire cutting is a kind of wire electric discharge cutting, which uses a continuously moving thin metal wire (called electrode wire) as an electrode to perform pulse spark discharge on the workpiece to remove metal and cut into shape. , Generally, the wire speed is lower than 0.2mm/s, the precision reaches 0.001mm level, and the surface quality is also close to the grinding level. The above-mentioned ultra-depth-of-field microscope is a continuous zoom solid microscope for binocular observation, which can magnify tiny objects to form a clear and positive stereoscopic image. The ultra-depth-of-field microscope has a long working distance, a large clear range, complete accessories, and is easy to operate. It can produce an upright three-dimensional space image, with a strong sense of three-dimensionality, clear and wide imaging.

105. Determine the gear molding shrinkage rate according to the measurement data of the gear sample.

In the embodiment of the present invention, the above measurement data refers to the key dimensions of the gear sample, including the diameter of the root circle and the diameter of the addendum circle. The size shrinkage rate of the gear is calculated by measuring the key dimensions of the gear. Since the gear dedendum circle diameter has the largest shrinkage rate, we choose the dedendum circle diameter d _f as the basis for measuring the shrinkage rate. The gear sample is measured through an ultra-depth-of-field microscope. First, the gear tooth part of the gear sample is enlarged under a high-magnification lens to check whether there are defects in the teeth of the gear sample. If there are defects, the sample will not be used. If the gear teeth If the surface is complete, replace the high-magnification lens with a low-magnification lens, so that the gear as a whole is displayed on the screen. Then use the three-point fixed circle method to determine the tooth profile of the dedendum circle and the addendum circle, and check whether the centers of the addendum circle and the dedendum circle coincide. The coincidence indicates that the teeth of the gear sample are shrinking synchronously. Finally, the diameter of the dedendum circle is measured using the plane measurement function of the ultra-depth-of-field microscope measurement system.

In the embodiment of the present invention, the cavity of the final molded gear mold needs to be appropriately enlarged. The gear cavity is designed according to the target gear size, and the mold cavity is precisely machined by using the slow wire cutting process. Finally, the super depth-of-field microscope is used to detect whether the gear mold size is within the error range.

Optionally, determining the gear molding shrinkage rate based on the measurement data of the gear sample includes: determining the size of the gear sample after the gear sample is stabilized; and determining the gear molding shrinkage rate according to the size of the gear sample.

In the embodiment of the present invention, because the polymer particles will absorb the water vapor in the air, in order to avoid too much change in the density of the polymer particles, resulting in excessive shrinkage fluctuations of the material, it is necessary to weigh the polymer particles after taking them out. The polymer material is fully dried before molding, until the weighing data of the polymer material remains stable. Then, the test was carried out under the obtained global optimal process parameters, and the injection-molded gear samples were placed in a ventilated place for cooling for 48 hours. After the dimensions were stable, the dimensions of the gear samples were measured. The dimensional shrinkage of gears is calculated by measuring the critical dimensions of the gears. The gear sample is measured through an ultra-depth-of-field microscope. First, the gear tooth part of the gear sample is enlarged under a high-magnification lens to check whether there are defects in the teeth of the gear sample. If there are defects, the sample will not be used. If the gear teeth If the surface is complete, replace the high-magnification lens with a low-magnification lens, so that the gear as a whole is displayed on the screen. Then use the three-point fixed circle method to determine the tooth profile of the dedendum circle and the addendum circle, and check whether the centers of the addendum circle and the dedendum circle coincide. The coincidence indicates that the teeth of the gear sample are shrinking synchronously. Finally, the diameter of the dedendum circle is measured using the plane measurement function of the ultra-depth-of-field microscope measurement system.

Optionally, determining the gear molding shrinkage rate according to the size of the gear sample includes: calculating the average dedendum circle diameter of a plurality of the above gear samples; and calculating the gear molding shrinkage rate according to the above average dedendum circle diameter.

根据得到的平均齿根圆直径/>

计算齿轮成型收缩率δ_e，并且收缩率数值保留至小数点后2位。In the embodiment of the present invention, the above-mentioned plurality of gear samples may be 10 or more gear samples. The diameter of the dedendum circle is measured by the plane measurement function of the super depth-of-field microscope measurement system. In order to ensure the calculation accuracy, the diameter of the dedendum circle is kept to 2 decimal places. Finally, the diameter of the dedendum circle of 10 gear samples is measured, and the average value is calculated to obtain the average value

According to the obtained average dedendum circle diameter />

Calculate the gear molding shrinkage rate δ _e , and keep the shrinkage rate value to 2 decimal places.

Gear molding shrinkage is shown in the following formula:

106. According to the gear molding shrinkage rate, determine the gear mold inversion cavity size parameters.

In the embodiment of the present invention, the inversion cavity size of the gear mold is calculated according to the above gear molding shrinkage ratio. As shown in the table below:

Optionally, the above-mentioned determining the gear mold inversion cavity size parameter according to the gear molding shrinkage ratio includes: determining the gear mold inversion cavity size parameter according to the target gear module and the gear molding shrinkage ratio.

In the embodiment of the present invention, the above-mentioned target gear modulus is m, and the inversion gear modulus is

The inversion gear modulus can also be negative; the number of teeth is z, the number of teeth of the target gear and the inversion gear are the same; the pressure angle is α, the pressure angle of the target gear and the inversion gear are the same; the tooth width is b, the target gear and the inversion gear The tooth width is the same.

107. Invert the cavity size parameters of the gear mold to determine the gear cavity size, and perform precision machining according to the gear cavity size to obtain the target gear injection mold.

In the embodiment of the present invention, the gear cavity size parameters are designed according to the inversion parameters, the gear cavity size is determined, and precision machining is performed to obtain the target gear injection mold.

Optionally, the above precision machining is carried out according to the size of the gear cavity to obtain the target gear injection mold, including: keeping the overall structure of the mold, the cooling system, the temperature control system and the pouring system unchanged, and adjusting the mold type according to the above gear cavity size The cavity is precisely machined to obtain the target gear injection mold.

In the embodiment of the present invention, precision machining is carried out according to the reverse gear cavity size. Except for changes in the cavity size, the overall structure of the mold, cooling system, temperature control system and pouring system remain unchanged, and the target gear injection mold can be obtained. .

108. Injection-molding the target gear according to the target gear injection mold to obtain the target gear finished product.

In the embodiment of the present invention, a precision injection molding machine is selected under the global optimal process to carry out a small modulus gear injection molding test to obtain an injection-molded gear sample, and the gear molding shrinkage rate is obtained from the gear sample, so as to determine according to the gear molding shrinkage rate The cavity size parameters of the gear mold are reversed to obtain the gear cavity size, and the precision machining is carried out according to the gear cavity size to obtain the target gear injection mold, and the injection molding is performed under the global optimal molding process parameters according to the target gear injection mold to obtain The target gear finished product is a high-precision small module gear.

In the embodiment of the present invention, the inverse cavity of the small modulus gear is parametrically designed by detecting the shrinkage rate of the critical dimension of the actual molding of the small modulus gear, which can reduce the number of trial molds and avoid time and cost At the same time, it can make the inversion design of small modulus gears simpler and more accurate, avoid the problem of inaccurate inversion design of small modulus gears, and greatly improve the injection molding accuracy of small modulus gears, which is beneficial to high Mass production of precision small modulus gears.

The above disclosures are only preferred embodiments of the present invention, and certainly cannot limit the scope of rights of the present invention. Therefore, equivalent changes made according to the claims of the present invention still fall within the scope of the present invention.

Claims (10)

1. The gear injection molding regulation and control method is characterized by comprising the following steps of:

obtaining a test parameter table of injection molding of a target gear;

performing a simulation test according to the test parameter table to obtain a simulation result;

determining global optimal technological parameters according to the simulation result;

performing injection molding test under the obtained global optimal technological parameters, and performing injection molding to obtain a gear sample;

determining the gear molding shrinkage rate according to the gear sample measurement data;

determining a size parameter of an inversion cavity of the gear die according to the gear molding shrinkage rate;

determining the size of a gear cavity according to the inversion cavity size parameter of the gear mold, and performing precision machining according to the size of the gear cavity to obtain a target gear injection mold;

and carrying out injection molding on the target gear according to the target gear injection mold to obtain a target gear finished product.

2. The gear injection molding control method according to claim 1, wherein the obtaining the table of test parameters for the injection molding of the target gear comprises:

obtaining test input parameters of a target gear;

determining a process parameter range according to the target gear material attribute;

and determining a test parameter table of the injection molding of the target gear according to the test input parameters and the process parameter range.

3. The method for controlling injection molding of gears according to claim 2, wherein said performing a simulation test according to said test parameter table to obtain a simulation result comprises:

according to the actual molding condition, establishing the target gear simulation model;

and after the analysis type and the analysis sequence are selected, performing a simulation test according to the test parameter table to obtain a simulation result.

4. The method for adjusting and controlling injection molding of gears according to claim 3, wherein said determining global optimum process parameters according to said simulation results comprises:

determining the maximum shrinkage and the volume shrinkage according to the simulation result;

determining the diameter of the addendum circle and the diameter of the root circle of the target gear simulation model according to the simulation result;

determining the diameter shrinkage rate of the addendum circle and the diameter shrinkage rate of the dedendum circle according to the addendum circle diameter and the dedendum circle diameter;

and determining global final process parameters by taking the maximum shrinkage, the volume shrinkage, the addendum circle diameter shrinkage and the root circle diameter shrinkage as response targets and taking the minimum response targets as optimization targets.

5. The method of gear injection molding control of claim 4, wherein said determining global final process parameters with said minimum response objective as an optimization objective comprises:

determining a response surface model between the process parameter and the response target;

and optimizing the response surface model by taking the minimum response target as an optimization target to obtain the global final process parameter.

6. The method for adjusting and controlling injection molding of gears according to claim 5, wherein the injection molding is performed under the obtained global optimum process parameters to obtain gear samples, and the injection molding comprises:

determining an initial gear cavity according to the size of the target gear;

precisely machining the initial mold cavity according to the initial gear cavity to obtain an initial injection mold;

and (3) carrying out injection molding through the initial injection mold to obtain a gear sample.

7. The method of claim 6, wherein determining the gear molding shrinkage based on the gear sample measurement data comprises:

determining the size of the gear sample after the gear sample is stable;

and determining the gear molding shrinkage rate according to the size of the gear sample.

8. The method of claim 7, wherein determining the gear molding shrinkage based on the size of the gear sample comprises:

calculating average root circle diameters of a plurality of the gear samples;

and calculating the gear molding shrinkage rate according to the average root circle diameter.

9. The method of claim 8, wherein determining the gear mold inversion cavity size parameter based on the gear molding shrinkage comprises:

and determining the inversion cavity size parameter of the gear die according to the modulus of the target gear and the molding shrinkage rate of the gear.

10. The method for controlling injection molding of gears according to claim 9, wherein said precisely machining according to the size of said gear cavity to obtain a target gear injection mold comprises:

and keeping the integral structure of the die, the cooling system, the temperature control system and the pouring system unchanged, and precisely processing the die cavity according to the size of the gear cavity to obtain the target gear injection die.

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