WO2017193968A1

WO2017193968A1 - Injection molding die sensor and in-process inspection method thereby

Info

Publication number: WO2017193968A1
Application number: PCT/CN2017/083989
Authority: WO
Inventors: 莫胜勇; 尹运文; 汪智勇; 杨毅; 高福荣
Original assignee: 群达模具(深圳)有限公司; 深圳市福达智能系统有限公司
Priority date: 2016-05-12
Filing date: 2017-05-11
Publication date: 2017-11-16
Also published as: CN107364076A

Abstract

An injection molding die sensor and an in-process inspection method thereby. The injection molding die comprises: a fixed mold (100), a moving mold (200), and a mold cavity (300). The sensor comprises: a sensor body (1), a surface thereof is entirely coated, with the exception of a portion in contact with the mold cavity (300), by an insulating layer, thereby forming, together with the fixed mold core (110), two electrodes for capacitance detection. A connecting wire (2), one end thereof is connected to the sensor body (1), and another end is connected to a power source to detect capacitor charging. Alternatively, the other end can be connected to a computer to send a voltage signal of a detected capacitance to the computer during the entirety of an injection molding process cycle. The voltage signal detected by the sensor can reflect at least one of the following: injection molding speed, injection molding mass, injection molding curing speed, or injection molding shrinkage. The invention thus monitors a wide range of contents.

Description

Sensor for injection mold and online detection method thereof

[0001] The present invention relates to the field of mold technology, and more particularly to a sensor for an injection mold and an on-line detection method thereof.

Background technique

[0002] With the fierce competition in the mass product market, promoting high efficiency, energy saving, environmental protection, and low cost has become a magic weapon and fundamental for enterprises to win in competition. One of the key links is the efficient production process of injection molding products. The high intelligence of quality, quality monitoring and control, as well as low-cost expenditures, efficient use of effective resources, etc., raise higher, more competitive, smarter and more automated requirements.

[0003] In the trial-molding stage of injection molding, it is necessary to set and optimize the molding process of the product, thereby reducing the number of trials and shortening the trial mode. The same injection molding process is a typical batch process. Maintaining a good and stable molding process is a necessary condition for obtaining high quality products, and this condition must be based on precise quality control of the injection molding cycle.

[0004] In order to solve the above problems, sensors are generally provided in an injection mold to monitor the injection molding process. However, the existing sensors generally can monitor a single information (for example, the pressure sensor only measures the pressure information during the injection cycle), and the function is single, and it is difficult to monitor various factors in the entire injection molding cycle.

technical problem

Problem solution

Technical solution

[0005] In order to solve the problem that the sensor used in the injection mold has a single function and is difficult to meet the needs of the enterprise, the embodiment of the invention provides a sensor for an injection mold and an on-line detection method thereof. The technical solution is as follows:

[0006] In one aspect, an embodiment of the present invention provides a sensor for an injection mold, the injection mold comprising: a fixed template, a movable template, and a fixed mold core and the movable template of the fixed template a cavity for forming a product between the mold cores, [0007] The sensor includes:

[0008] The sensor body is disposed in the movable mold core and is in contact with the cavity, and the sensor body surface is provided with an insulating layer except for the cavity contact surface, and the sensor body is used for Forming two poles of the detecting capacitor with the fixed mold core;

[0009] wiring, one end is connected to the sensor body, and the other end is connected to a power source for charging the detecting capacitor, or the other end thereof is connected to a computer, and the detecting capacitor is transmitted for the computer. A voltage signal throughout the injection molding cycle for monitoring at least one of injection speed, injection weight, cure rate of injection molding, and shrinkage of injection molding in the cavity during the injection molding cycle.

[0010] In the above sensor according to the embodiment of the present invention, the sensor further includes:

[0011] a voltage signal amplifier connected to the wiring for amplifying the voltage signal;

And [0012] an analog to digital converter coupled to the voltage signal amplifier for converting a voltage signal amplified by the voltage signal amplifier into a digital signal.

[0013] In the above sensor according to the embodiment of the present invention, the sensor body is provided with a fixing screw center hole for extending one end of the wire.

[0014] The sensor further includes: a wire fixing screw fixedly connected to one end of the wire and cooperating with the fixing screw center hole for fixedly connecting one end of the wire to the sensor body.

[0015] In the above sensor according to the embodiment of the invention, the insulating layer of the sensor body is made of alumina ceramic or zirconia ceramic, and has a thickness of 0.02 mm to 0.50 mm.

[0016] In the above sensor according to the embodiment of the invention, the sensor body is prepared by using a mold steel material.

In the sensor according to the embodiment of the invention, the sensor body has a square shape, and the length, the width, and the height of the sensor are in the range of 15 mm to 200 mm.

[0018] In the above sensor according to the embodiment of the present invention, the sensor body is mounted at a front end or an end of the cavity, and a front end of the cavity is an end of the cavity close to the gate of the injection mold. The end of the cavity is one end away from the gate of the injection mold.

[0019] In another aspect, an embodiment of the present invention provides an online detection method for a sensor, the method comprising: [0020] mounting a sensor body of the sensor in a movable mold core of an injection mold, and The fixed mold core of the injection mold constitutes a detection capacitor;

[0021] charging a predetermined amount of power for the detection capacitor; [0022] injecting a preset filling material into a cavity of the injection mold;

[0023] realizing monitoring the voltage signal of the detecting capacitor during the whole injection molding period, the voltage signal is used for online monitoring of the injection speed in the cavity in the injection molding cycle, the injection weight, the curing rate of the injection molding, and the shrinkage of the injection molding At least one of the rates.

[0024] In the above method of the embodiment of the present invention, the sensor body is mounted at a front end or an end of the cavity, and a front end of the cavity is an end of the cavity close to the gate of the injection mold. The end of the cavity is one end away from the gate of the injection mold.

[0025] In the above method of the embodiment of the present invention, the actual monitoring of the voltage signal of the detecting capacitor during the entire injection molding period includes:

[0026] The sensor body mounted at the front end or the end of the cavity is monitored for a voltage signal provided by the generated detection capacitor.

Advantageous effects of the invention

Beneficial effect

[0027] The beneficial effects brought by the technical solutions provided by the embodiments of the present invention are:

[0028] The sensor body and the wiring constitute a sensor, wherein the sensor body is disposed in the movable mold core of the injection mold and is in contact with the cavity of the injection molding module, and the surface of the sensor body is provided with insulation except for the contact surface of the cavity. a layer for connecting the two poles of the detecting capacitor with the fixed mold core, one end of the wiring is connected to the sensor body, the other end is connected to the power source for charging the detecting capacitor, or the other end is connected to the computer, and is used for the computer The detection detects a voltage signal of the capacitor throughout the injection cycle, and the voltage signal is used to monitor at least one of the injection speed in the cavity, the injection weight, the curing rate of the injection molding, and the shrinkage of the injection molding in the injection molding cycle. The sensor operates based on a change in the dielectric constant of the capacitor and causes a change in the voltage signal in the sense capacitor, so that the computer connected to the sensor can monitor the injection speed, injection weight, and injection molding in the cavity during the injection cycle. At least one of the curing rate and the shrinkage rate of the injection molding is rich in monitoring content, which can effectively reflect various injection molding information that needs attention in the injection molding cycle, and is highly practical. In addition, the sensor also utilizes the fixed mold of the existing injection mold. As an electrode for detecting capacitance, the core effectively reduces the complexity of the structure of the sensor, and also reduces the manufacturing cost of the sensor, and is economical.

Brief description of the drawing DRAWINGS

[0029] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly described below. Obviously, the drawings in the following description are only some of the present invention. For the embodiments, those skilled in the art can obtain other drawings according to the drawings without any creative work.

1 is a schematic structural view of an injection mold according to Embodiment 1 of the present invention;

2 is a schematic structural diagram of a principle of detecting capacitance molding according to Embodiment 1 of the present invention;

3 is a diagram showing a detection result of a voltage signal according to Embodiment 1 of the present invention;

4 is a schematic structural diagram of a sensor according to Embodiment 1 of the present invention;

5 is a schematic diagram of a sensor mounting position according to Embodiment 1 of the present invention;

6 is a flowchart of a method for online detection of a sensor according to Embodiment 2 of the present invention.

Embodiments of the invention

The embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0037] Embodiment 1

[0038] Embodiments of the present invention provide a sensor for an injection mold, which is suitable for monitoring the injection molding cycle of various non-conductive filling materials. Referring to FIG. 1 , the injection mold may include: a fixed template 100, a movable template 200, And a cavity 300 for forming a product between the fixed mold core 110 of the stationary die plate 100 and the movable mold core 210 of the movable die plate 200 (the thickness dimension of the cavity 300 in Fig. 1 is relatively small).

[0039] Referring to FIG. 1, the sensor includes:

[0040] The sensor body 1 is disposed in the movable mold core 210 and is in contact with the cavity 300 (ie, the sensor body 1 is inserted into the movable mold core 210, and one end surface thereof is in contact with the cavity 300, in practical application. The sensor body 1 is in contact with the cavity 300, and the contact mold core 210 and the cavity 300 are in the same plane. The surface of the sensor body 1 is provided with an insulating layer except for the contact surface of the cavity 210. The sensor body 1 is provided. It is used to form two poles of the detection capacitance with the fixed mold core 110.

[0041] The wiring 2 has one end connected to the sensor body 1 and the other end connected to the power source for charging the detecting capacitor, or the other end of which is connected to the computer for transmitting the detecting capacitor for the computer during the entire injection molding cycle. The voltage signal is used to monitor at least one of the injection speed in the cavity 300, the injection weight, the curing rate of the injection molding, and the shrinkage of the injection molding in the injection molding cycle. In practical applications, since the general computer has a power supply, the other end of the wiring 2 can be connected to the computer, and the voltage is detected by the computer to detect the capacitance, and the computer transmits the voltage of the detection capacitor during the entire injection molding cycle.

[0042] In the present embodiment, referring to FIG. 2, the surface of the sensor body 1 is provided with an insulating layer except for the contact surface with the cavity 210, and has a cavity 300 spaced apart from the fixed mold core 110, and the sensor body 1 and The mold core 110 is generally made of a conductive material, and under the action of the air-insulated cavity 300, a detection capacitor is formed, wherein the sensor body 1 can be charged by an external power source, and the fixed mold core 110 is grounded.

[0043] Further, the capacitance of the detection capacitor depends only on the dielectric constant after the sensor is mounted, and the dielectric constant depends on the medium between the sensor body 1 and the fixed mold core 110. During the entire injection molding cycle, the cavity 300 is gradually filled with air by the hot-melt filling material, and then cooled by the hot-melt filling material to the solid filling material. Under the condition that the charging charge of the detecting capacitor is constant, the voltage of the detecting capacitor is detected. It is inversely proportional to the dielectric constant. Specifically, you can refer to the following formula:

[0044]

[0045] wherein, U is a voltage signal, C is a capacitance value of the detection capacitor, Q is a charge amount of the detection capacitor, A is a facing area of the sensor body 1 and the fixed mold core 110, and D is a sensor body 1 and The distance between the mold cores 110, ε is the dielectric constant.

[0046] Referring to FIG. 3, during the entire injection molding cycle, the mold closing phase is first experienced, that is, the fixed template 100 is in contact with the movable template 200. Thereafter, the detecting capacitor is activated after being charged, and due to the cavity 300. For air only, the dielectric constant of the detection capacitor remains unchanged, and the corresponding voltage signal remains unchanged; then the filling material is injected into the cavity 300 at a constant rate (ie, the injection phase in Figure 3), due to the dielectric of the filler material. The constant is smaller than the dielectric constant of air. As the filling material is continuously injected, the dielectric constant of the detecting capacitor decreases, and the corresponding voltage signal becomes larger. As the cavity 300 fills the filling material, it enters. During the packing phase, a small amount of filler material is still injected into the cavity 300 to fill the gap formed by the curing shrinkage of the first injected filler material. In the pressure holding phase, since the filling material is still injected, the detection is performed. The dielectric constant of the capacitor will still decrease by a small amount, and the corresponding voltage signal will increase a little. After the pressure holding phase, it will enter the cooling phase. The filling material 300 is injected into the cavity, the filling material Jian start cooling liquid to a solid state, along with the dielectric constant of the capacitance detection has increased; Finally, when the filling material After the cooling is formed, the mold is smashed (ie, enters the mold stage), and the detection capacitance is disabled as the fixed template 100 and the movable mold 200 are separated.

[0047] In addition, the voltage signal of the sensor is shown in FIG. 3 throughout the injection molding cycle. It can be seen that the variation characteristics of the voltage signal at different stages are different, respectively reflecting the process of different stages and the quality information of the filling material. Specifically as follows:

[0048] During the injection phase, as the liquid fill material is injected into the cavity, the air medium between the capacitor plates is quickly replaced by the liquid fill material, and the voltage signal is significantly increased. The computer connected to the sensor can use this signal to detect the position of the front end of the liquid filling material in the cavity 300, thereby obtaining the filling speed of the filling material (for example: dividing a plurality of sensors at a predetermined distance apart, and then comparing a plurality of sensors The sensor begins to detect a significant increase in the inter-turn difference of the voltage signal to calculate the fill speed).

[0049] During the holding phase, the slope of the voltage signal changes significantly, and the rise is slow. This is because only a small amount of liquid filling material is continuously pressed into the (injection) cavity 300 after the cavity 300 is filled, to supplement the filling material. The space formed by curing shrinkage (holding pressure). The computer connected to the sensor can use this signal to detect the weight of the filling material online (for example: to obtain the weight information of the filling material according to the known injection speed and the continuous time during the injection phase).

[0050] During the cooling phase, the voltage signal changes more gently, with a slight downward trend. The reason for this is that the liquid filling material becomes solid after cooling and solidification, and on the other hand, a minute air layer is formed in the cavity 300. The computer connected to the sensor can utilize the process characteristics of the measurement signal combining process to detect the cure rate and shrinkage of the product.

[0051] Optionally, referring to FIG. 4, the sensor may further include:

[0052] A voltage signal amplifier 4, connected to the wiring 2, is used to amplify the voltage signal.

The analog-to-digital converter 5 is connected to the voltage signal amplifier 4 for converting the voltage signal amplified by the voltage signal amplifier 4 into a digital signal.

In the present embodiment, the voltage signal on the sensor body 1 is amplified and converted into a computer-recognizable digital signal, which facilitates rapid analysis of the processed data by a computer connected to the sensor.

[0055] Optionally, referring to FIG. 1, the sensor body 1 is provided with a fixing screw center hole (not shown in the drawing) for one end of the wire 2.

[0056] The sensor may further include: a wire fixing screw 3 fixedly connected to one end of the wire 2 (for example: welding And cooperate with the center hole of the fixing screw (for example, screw connection) for fixing one end of the wire 2 to the sensor body 1 to prevent the wire 2 from coming off the sensor body 1.

[0057] Optionally, the insulating layer of the sensor body 1 is made of alumina ceramic or zirconia ceramic and has a thickness of 0.02 mm to 0.50 mm. In the present embodiment, the outer surface of the sensor body 1 is a high-temperature and friction-resistant high-insulation layer, which is sprayed on the surface of the metal substrate by a high pressure of 100 MPa or more at a high temperature of 3000 ° C or higher.

The thickness of the insulating layer is 0.02mm~0.50mm, the surface is polished and polished, the dimensional tolerance can reach 0.005mm~0.01mm, the surface finish can reach above V9, the heat insulation effect is above 200°C, the thermal spray coefficient Close to steel, the Mohs hardness is above 8.5.

[0058] In addition, the processing flow of spraying the insulating layer on the surface of the sensor body 1 is as follows: sensor body preparation→sensor body processing→sensor body drilling screw hole→sensor body screw hole tapping screw→sensor body surface insulation layer spraying→insulating layer surface grinding Light processing → sensor size detection.

[0059] Alternatively, the sensor body 1 may be fabricated using a mold steel material (for example: P20, S136, 718, 718)

H, etc.).

Further, the sensor body 1 may be a square cylinder or the like, and is selected as a square in the embodiment, and has a length, a width, and a high size ranging from 15 mm to 200 mm, and the specific size may be customized according to design requirements. Wiring 2 can be a special power cord or an anti-static induction special power cord. The size of the wiring fixing screw 3 is M2, M3 or M4.

[0061] Optionally, referring to FIG. 5, the sensor body 1 is mounted at the front end or the end of the cavity 300. The front end of the cavity 300 is the end of the cavity 300 near the injection mold 310 of the injection mold. The end of the cavity 300 is Keep away from the end of the injection mold inlet 310. In the present embodiment, the sensor is disposed using the above two positions because the filling condition of the filling material at the front end or the end position of the cavity 300 can best fully reflect the filling condition of the filling material in the cavity 300.

[0062] In the embodiment of the present invention, the sensor body and the wiring constitute a sensor, wherein the sensor body is disposed in the movable mold core of the injection mold and is in contact with the cavity of the injection molding module, and the surface of the sensor body is in contact with the cavity contact surface. An insulating layer is disposed for forming two poles of the detecting capacitor with the fixed mold core, one end of the wiring is connected to the sensor body, and the other end is connected to the power source for charging the detecting capacitor, or the other end is connected to the computer. Used to transmit a voltage signal for the computer to detect the capacitance throughout the injection cycle. This voltage signal is used to monitor the injection speed, injection weight, and injection molding in the cavity during the injection molding cycle. At least one of the curing rate and the shrinkage of the injection molding. The sensor operates based on a change in the dielectric constant of the capacitor and causes a change in the voltage signal in the sense capacitor, so that the computer connected to the sensor can monitor the injection speed, injection weight, and injection molding in the cavity during the injection cycle. At least one of the curing rate and the shrinkage rate of the injection molding is rich in monitoring content, which can effectively reflect various injection molding information that needs attention in the injection molding cycle, and is highly practical. In addition, the sensor also utilizes the fixed mold of the existing injection mold. As an electrode for detecting capacitance, the core effectively reduces the complexity of the structure of the sensor, and also reduces the manufacturing cost of the sensor, and is economical.

Embodiment 2

An embodiment of the present invention provides an online detection method for a sensor. The sensor is the sensor described in Embodiment 1. Referring to FIG. 6, the method includes:

[0065] Step S21, the sensor body of the sensor is installed in the movable mold core of the injection mold, and forms a detection capacitance with the fixed mold core of the injection mold.

[0066] In this embodiment, the formation of the detection capacitor is originally described in the first embodiment, and details are not described herein.

[0067] Step S22, charging a predetermined amount of power for detecting the capacitance.

[0068] Step S23, injecting a preset filling material into the cavity of the injection mold.

[0069] Step S24, the real monitoring monitors the voltage signal of the capacitor during the entire injection molding cycle, and the voltage signal can be used for online monitoring of the injection speed in the cavity during the injection molding cycle, the injection weight, the curing rate of the injection molding, and the shrinkage ratio of the injection molding. at least one.

[0070] In the embodiment, how the voltage signal reflects the injection molding information is described in the first embodiment.

, I won't go into details here.

[0071] Alternatively, the sensor body may be installed at the front end or the end of the cavity, and the front end of the cavity is one end of the cavity near the gate of the injection mold, and the end of the cavity is one end away from the gate of the injection mold.

[0072] Further, the foregoing step S24 can be implemented as follows:

[0073] The sensor body mounted at the front end or the end of the cavity is monitored for a voltage signal provided by the generated detection capacitor. In the present embodiment, the sensor is disposed using the above two positions because the filling condition of the filling material at the front end or the end position of the cavity most fully reflects the filling state of the filling material in the cavity.

[0074] Embodiments of the present invention install a sensor body of a sensor in a movable mold core of an injection mold, and a note The fixed mold core of the plastic mold constitutes a detecting capacitor; a predetermined amount of electricity is charged for detecting the capacitor; a preset filling material is injected into the cavity of the injection mold; and the voltage signal of the capacitor during the entire injection molding period is monitored and monitored, and the voltage signal can be It is used to monitor at least one of the injection speed in the cavity in the injection molding cycle, the injection weight, the curing rate of the injection molding, and the shrinkage rate of the injection molding. The voltage signal monitored by the method can monitor at least one of the injection speed in the cavity during the injection cycle, the injection weight, the curing rate of the injection molding, and the shrinkage rate of the injection molding. The monitoring content is rich, and can effectively reflect various needs in the injection molding cycle. The injection molding information of interest is practical.

[0075] The foregoing serial numbers of the embodiments of the present invention are merely for the description, and do not represent the advantages and disadvantages of the embodiments.

The above is only the preferred embodiment of the present invention, and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., which are included in the spirit and principles of the present invention, should be included in the present invention. Within the scope of protection of the invention.

Claims

Claim

[Claim 1] A sensor for an injection mold, the injection mold comprising: a fixed template (100), a movable template (200), and a fixed mold core (110) and the fixed template (100) A cavity (300) for forming a product between the movable mold cores (210) of the movable template (200), wherein the sensor comprises:

a sensor body (1) penetratingly disposed in the movable mold core (210) and the cavity

(300) contacting, the surface of the sensor body (1) is provided with an insulating layer except for a contact surface with the cavity (210), and the sensor body (1) is used for the fixed mold core (1 10) Constituting the two poles of the detection capacitor;

a wire (2) connected at one end to the sensor body (1), the other end of which is connected to a power source for charging the detection capacitor, or the other end of which is connected to a computer for transmitting the The voltage signal of the capacitor during the entire injection cycle is detected, and the voltage signal is used to monitor at least one of the injection speed, the injection weight, the curing rate of the injection molding, and the shrinkage of the injection molding in the cavity (300) in the injection molding cycle.

[Claim 2] The method according to claim 1, wherein the sensor further comprises:

a voltage signal amplifier (4) connected to the wiring (2) for amplifying the voltage signal;

An analog-to-digital converter (5) is coupled to the voltage signal amplifier (4) for converting a voltage signal amplified by the voltage signal amplifier (4) into a digital signal.

[Claim 3] The method according to claim 1, wherein the sensor body (1) is provided with a fixing screw center hole for extending one end of the wire (2),

The sensor further includes: a wire fixing screw (3) fixedly connected to one end of the wire (2) and cooperating with the fixing screw center hole for connecting one end of the wire (2) with the sensor body (1) Fixed connection.

[Claim 4] The method according to claim 1, wherein the insulating layer of the sensor body (1) is made of alumina ceramic or zirconia ceramic and has a thickness of 0.02 mm to 0.50 mm.

[Clave 5] The method according to claim 1, characterized in that the sensor body (1) is prepared using a mold steel material. The method according to claim 5, wherein the sensor body (1) is square, and the length, width and height of the sensor are in the range of 15 mm to 200 mm.

The method according to any one of claims 1 to 6, wherein the sensor body (1) is mounted at a front end or an end of the cavity (300), and the front end of the cavity (300) is The cavity (300) is adjacent to one end of the injection mold (310), and the end of the cavity (300) is away from one end of the injection mold (310). An online detection method for a sensor according to claim 1, wherein said method comprises:

Mounting the sensor body of the sensor in a movable mold core of the injection mold, and forming a detection capacitance with the fixed mold core of the injection mold;

Charging the detection capacitor with a predetermined amount of power;

Injecting a predetermined filling material into a cavity of the injection mold;

The voltage signal of the detecting capacitor during the whole injection molding period is monitored, and the voltage signal is used for online monitoring of at least the injection speed, the injection weight, the curing rate of the injection molding, and the shrinkage rate of the injection molding in the cavity during the injection molding cycle. One.

The method according to claim 8, wherein the sensor body is mounted at a front end or an end of the cavity, and a front end of the cavity is an end of the cavity near a gate of the injection mold. The end of the cavity is one end away from the gate of the injection mold. The method according to claim 9, wherein the actual monitoring of the voltage signal of the detecting capacitor during the entire injection molding cycle comprises:

The sensor body mounted at the front end or the end of the cavity is monitored for the voltage signal provided by the generated detection capacitor.