JP5917340B2 - Injection molding machine - Google Patents

Description

  The present invention relates to an injection molding machine.

  The injection molding machine includes a cylinder to which resin pellets as a molding material are supplied, and a heating source for heating the cylinder. The injection molding machine manufactures a molded product by melting a resin in a cylinder and filling the melted resin into a cavity space in a mold apparatus.

  A supply port for supplying resin pellets is provided at the rear of the cylinder. The rear part of the cylinder is kept at a temperature at which the surface of the resin does not melt so that resin bridging (agglomeration) does not occur. Therefore, the rear part of the cylinder is cooled by a cooling device having a refrigerant flow path inside.

  A heating source is provided in front of the cooling device. The output of the heating source is feedback controlled so that the cylinder temperature becomes the set temperature (see, for example, Patent Document 1). The temperature of the cylinder is measured by a temperature sensor.

Japanese Patent Laid-Open No. 11-227019

  Conventionally, a controller of an injection molding machine has monitored a measurement result of a temperature sensor or the like as a factor that determines a state of a resin in a cylinder. However, the number of temperature sensors installed is limited, and detailed information on the cylinders was not known.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide an injection molding machine capable of obtaining detailed information on a cylinder.

In order to solve the above problems, an injection molding machine according to an aspect of the present invention is provided.
A cylinder to which the molding material is supplied;
A heating source for heating the cylinder;
Estimating the temperature at any location in the cylinder using a heat transfer model based on the heat transfer equation of the cylinder, the heat transfer equation of the material in the cylinder, and an equation representing heat inflow and outflow in the heating source With
The estimation unit inputs an output of the heating source at a predetermined future time to the heat transfer model, and predicts a temperature at an arbitrary position in the cylinder at the predetermined future time.

  ADVANTAGE OF THE INVENTION According to this invention, the injection molding machine from which the detailed information of a cylinder is obtained is provided.

It is a figure which shows the injection molding machine by one Embodiment of this invention. It is a figure which shows the principal part of the injection molding machine by one Embodiment of this invention. It is explanatory drawing of the heat conduction equation of the cylinder by one Embodiment of this invention. It is explanatory drawing of the heat conduction equation of the substance in the cylinder by one Embodiment of this invention. It is explanatory drawing of the formula showing the inflow and outflow of the heat in the heating source by one Embodiment of this invention.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. In the drawings, the same or corresponding components are denoted by the same or corresponding reference numerals, and description thereof is omitted.

  FIG. 1 is a view showing an injection molding machine according to an embodiment of the present invention. In the following description, it is assumed that the resin injection direction is the front and the direction opposite to the resin injection direction is the rear.

  The injection molding machine 10 injects the resin melted in the cylinder 11 from the nozzle 12 and fills the cavity space in the mold apparatus. The mold apparatus includes a fixed mold and a movable mold, and a cavity space is formed between the fixed mold and the movable mold when the mold is clamped. The resin cooled and solidified in the cavity space is taken out as a molded product after the mold is opened. Resin pellets as a molding material are supplied from the hopper 16 to the rear portion of the cylinder 11.

  The injection molding machine 10 includes a metering motor 41 that rotates the screw 13 disposed in the cylinder 11. The weighing motor 41 may be a servo motor. The rotation of the metering motor 41 is transmitted to the injection shaft 43 via a connecting member 42 such as a belt or a pulley, and the screw 13 is rotated. Then, the flight (screw thread) of the screw 13 moves, and the resin filled in the screw groove of the screw 13 is sent forward.

  The injection molding machine 10 includes an injection motor 51 that moves the screw 13 in the axial direction. The injection motor 51 may be a servo motor. The rotation of the injection motor 51 is transmitted to the ball screw shaft 52. A ball screw nut 53 that moves forward and backward by the rotation of the ball screw shaft 52 is fixed to a pressure plate 54. The pressure plate 54 is movable along guide bars 55 and 56 fixed to a base frame (not shown). The forward / backward movement of the pressure plate 54 is transmitted to the screw 13 through a bearing 57, a resin pressure detector (for example, a load cell) 58, and an injection shaft 43, and the screw 13 is advanced and retracted. The advance / retreat amount of the screw 13 is detected by a position detector 59 attached to the pressure plate 54.

  The operation of the injection molding machine 10 is controlled by the controller 60. The controller 60 includes a CPU and a memory, and implements various functions by causing the CPU to execute programs stored in the memory. The controller 60 includes, for example, a weighing processing unit 61 that controls the weighing process and a filling processing unit 62 that controls the filling process.

  Next, the operation of the injection molding machine 10 will be described.

  In the weighing process, the weighing processing unit 61 rotates the screw 13 by rotating the weighing motor 41. If it does so, the flight (screw thread) of the screw 13 will move and the resin pellet with which the screw groove of the screw 13 was filled will be sent ahead. The resin is heated by heat from the cylinder 11 while moving forward in the cylinder 11 and is completely melted at the tip of the cylinder 11. As the molten resin is accumulated in front of the screw 13, the screw 13 moves backward. When the screw 13 moves backward by a predetermined distance and a predetermined amount of resin is accumulated in front of the screw 13, the weighing processing unit 61 stops the rotation of the weighing motor 41 and stops the rotation of the screw 13.

  In the filling step, the filling processing unit 62 drives the injection motor 51 to rotate, advances the screw 13, and pushes the molten resin into the cavity space in the mold apparatus in the mold-clamped state. The force with which the screw 13 pushes the molten resin is detected as a reaction force by the resin pressure detector 58. That is, the resin pressure applied to the screw 13 (resin injection pressure) is detected. Since the resin shrinks by cooling in the cavity space, the resin pressure (resin injection pressure) applied to the screw 13 is maintained at a predetermined pressure in the pressure holding step in order to replenish the resin for heat shrinkage.

  FIG. 2 is a view showing a main part of an injection molding machine according to an embodiment of the present invention.

The injection molding machine 10 includes a cylinder 11, a screw 13 that sends resin in the cylinder 11, a plurality of heating sources H _{1 to} H ₄ that heat the cylinder 11, and a cooling device 30 that cools the rear portion of the cylinder 11. .

  The screw 13 is disposed in the cylinder 11 so as to be rotatable and movable in the axial direction. The screw 13 integrally includes a screw rotating shaft 14 and a flight 15 provided in a spiral shape around the screw rotating shaft 14. When the screw 13 rotates, the flight 15 of the screw 13 moves, and the resin pellet filled in the screw groove of the screw 13 is sent forward.

  For example, as shown in FIG. 2, the screw 13 is distinguished as a supply unit 13a, a compression unit 13b, and a measurement unit 13c from the rear (the hopper 16 side) to the front (the nozzle 12 side) along the axial direction. The supply part 13a is a part which receives resin and conveys it ahead. The compression part 13b is a part that melts while compressing the supplied resin. The measuring unit 13c is a part that measures a certain amount of molten resin. The depth of the screw groove of the screw 13 is deeper at the supply unit 13a, shallower at the measuring unit 13c, and shallower toward the front in the compression unit 13b. The configuration of the screw 13 is not particularly limited. For example, the depth of the screw groove of the screw 13 may be constant.

As the heating sources H _{1 to} H ₄ , for example, a heater that heats the cylinder 11 from the outside is used. The heater is provided so as to surround the outer periphery of the cylinder 11.

The plurality of heating sources H _{1 to} H ₄ are arranged along the axial direction of the cylinder 11, and the cylinder 11 is individually heated by dividing it into a plurality of zones (four zones Z _{1 to} Z _{4 in} FIG. 3) in the axial direction. To do. The plurality of heating sources H _{1 to} H ₄ are feedback-controlled by the controller 60 so that the temperatures of the zones Z _{1 to} Z ₄ become set temperatures. Temperature of each zone _Z 1 to Z ₄ is measured by the temperature sensor _S 1 to S _4. The nozzle 12 may also be provided with a heating source.

The cooling device 30 is provided behind the plurality of heating sources H _{1 to} H ₄ . The cooling device 30 cools the rear part of the cylinder 11, and the temperature of the rear part of the cylinder 11 is set to a temperature at which the resin pellet surface does not melt so that the resin pellet bridge (agglomeration) does not occur in the rear part of the cylinder 11 or in the hopper 16. Keep temperature. The cooling device 30 has a flow path 31 of a coolant such as water or air.

  The controller 60 includes an estimation unit 63 that estimates the temperature at an arbitrary position in the cylinder 11 using a heat transfer model. The heat transfer model is stored in a memory or the like of the controller 60 and is read out as necessary.

The heat transfer model includes a heat conduction equation of the cylinder 11, a heat conduction equation of a substance in the cylinder 11 (hereinafter also referred to as “in-cylinder substance”), and each heating source H _k (in FIG. 2, k = 1, 2, 3). , 4) is based on the equation representing the inflow and outflow of heat. Hereinafter, each formula will be described. In each formula, the same symbol has the same meaning.

  FIG. 3 is an explanatory diagram of a heat conduction equation of a cylinder according to an embodiment of the present invention. The cylinder heat conduction equation is expressed by the following equation (1), for example. In the formula (1), for simplification of the formula, the temperature of the cylinder 11 is approximated to be substantially uniform around the center line of the cylinder 11 and is two-dimensionalized. In addition, in the later-described formulas (2) and (3), they are similarly two-dimensional.

上記式（１）中、ｘはシリンダ軸方向（前後方向）における位置座標、ｙはシリンダ径方向における位置座標、Ｒ_ｏｕｔはシリンダ１１の外周面の半径、Ｔ（ｔ）は時刻ｔにおける座標（ｘ，ｙ）での温度、αはシリンダ１１の熱拡散率［ｍ^２／ｓ］を表す。ｘ座標の原点はシリンダ１１の前端面であり、前端面から後端面に向かうほどｘが大きくなる。また、ｙ座標の原点はシリンダ１１の外周面であり、外周面から内周面に向かうほどｙが大きくなる。

In the above formula (1), x is a position coordinate in the cylinder axial direction (front-rear direction), y is a position coordinate in the cylinder radial direction, R _out is a radius of the outer peripheral surface of the cylinder 11, and T (t) is a coordinate at time t ( The temperature at x, y), α, represents the thermal diffusivity [m ² / s] of the cylinder 11. The origin of the x coordinate is the front end surface of the cylinder 11, and x increases from the front end surface toward the rear end surface. The origin of the y coordinate is the outer peripheral surface of the cylinder 11, and y increases from the outer peripheral surface toward the inner peripheral surface.

The above equation (1) is discretized, and the region (that is, the cylinder 11) in which the above equation (1) is defined is divided into a plurality of minute regions (elements). Let T _{i, j} (t) be the temperature at the time t of the minute region at the coordinates (i × Δx, j × Δy). i is an integer of 0 to m, and j is an integer of 0 to n. If the length of the cylinder 11 in the axial direction is L, the equation L = m × Δx is established. Further, if the radius of the inner peripheral surface of the cylinder 11 is R _in and the radius R _out of the outer peripheral surface of the cylinder 11 is satisfied, an equation of R _out −R _in = n × Δy is established. The number (m + 1) × (n + 1) of minute regions in the cylinder 11 is set so that the temperature at an arbitrary position in the cylinder 11 can be solved.

The temperature rise rate (one-time differentiation of the temperature T _{i, j} (t)) of the micro area is determined by the flow of heat into and out of the micro area, and the temperature T _{i, j} (t) of the micro area and the micro area It is determined by the temperature difference from the temperature of the minute region adjacent to the. Therefore, the one-time differentiation of the temperature T _{i, j} (t) of the micro area is the temperature T _{i, j} (t) of the micro area and the temperatures T _{i−1, j} (t), T _{i + 1 of the} adjacent micro area. _{, j} (t), T _{i, j-1} (t), and T _{i, j + 1} (t) (where i is an integer from 1 to m-1 and j is an integer from 1 to n-1). .

Temperature T _m of a micro area in the cylinder rear end (coordinate _{x = m × Δx), j} (t) is maintained at substantially the same temperature as the outside air temperature T _a by the cooling device 30. Therefore, a temperature fixing condition is given as a boundary condition between the cylinder rear end and the outside air. _That, T m, the expression of j (t) = _{T a} is established. Note that the temperature T _{m, j} (t) at the rear end of the cylinder may be maintained at _a predetermined temperature T _c (T _c > T _a ) that is higher than the temperature T _{a of} the outside air.

On the other hand, boundary conditions between the cylinder front end (coordinate x = 0) and outside air, boundary conditions between the cylinder outer periphery (coordinate y = 0) and outside air, boundary conditions between the cylinder outer periphery (coordinate y = 0) and the heating source H _k , As a boundary condition between the cylinder inner circumference (coordinate y = n × Δy) and the substance in the cylinder, a heat flux boundary condition is given.

Accordingly, the temperature increase rate (one-time differentiation of the temperature T _{0, j} (t)) at the front end of the cylinder (coordinate x = 0) is the temperature of the minute region, the temperature of the minute region adjacent to the minute region, It is determined by the temperature T _{a of} the outside air, the heat transfer coefficient [W / (m ² · ° C.)] between the cylinder 11 and the outside air, and the like.

Similarly, in the cylinder outer periphery (coordinate y = 0), the temperature increase rate (one-time differentiation of the temperature T _{i, 0} (t)) in contact with the outside air is adjacent to the temperature of the minute region and the minute region. It is determined by the temperature of the minute region to be performed, the temperature T _{a of} the outside air, the heat transfer coefficient [W / (m ² · ° C.)] between the cylinder 11 and the outside air, and the like.

In addition, the temperature increase rate (one-time differentiation of the temperature T _{i, 0} (t)) of the minute region in contact with the heating source H _k in the cylinder outer periphery (coordinate y = 0) is the temperature of the minute region, the minute region and the temperature of the adjacent micro areas, the temperature _T hk of the heating source _{H k} (t), the heat transfer coefficient between the cylinder 11 and the heating source ^{_{H k [W / (m 2}} · ℃)] determined by such.

Further, the temperature rise rate (one-time differentiation of the temperature T _{i, n} (t)) on the inner circumference of the cylinder (coordinate y = n × Δy) is the temperature of the minute region, the minute region adjacent to the minute region. , The temperature T ^fl _i (t) of the substance in the cylinder, the heat transfer coefficient [W / (m ² · ° C.)] between the substance in the cylinder and the cylinder 11, and the like. The temperature T ^fl _i (t) of the substance in the cylinder will be described later.

  The in-cylinder material may be, for example, air when the temperature of the cylinder 11 is raised before molding, or resin when molding, and may change during the molding.

  FIG. 4 is an explanatory diagram of a heat conduction equation of a material in a cylinder according to an embodiment of the present invention. The heat conduction equation of the in-cylinder material is expressed by, for example, the following formula (2) (where i is an integer of 1 to m−1). In the formula (2), the temperature distribution of the substance in the cylinder is uniform in the radial direction of the cylinder 11 in order to simplify the formula.

上記式（２）中、Ｔ^ｆｌ _ｉ（ｔ）は座標ｘ＝ｉ×Δｘにおける微小空間の時刻ｔの温度［℃］、ρ_ｉｎはシリンダ内物質の密度［ｋｇ／ｍ^３］、ｃ_ｉｎはシリンダ内物質の定圧比熱［Ｊ／ｋｇ］を表す。
ｑ_１は、座標ｘ（ｘ＝ｉ×Δｘ）における微小領域に、前方（図４中左側）の微小領域から流れ込む単位時間当たりの流入熱量［Ｗ］を表す。流入熱量ｑ_１は、微小領域間の温度差（Ｔ^ｆｌ _ｉ−１（ｔ）−Ｔ^ｆｌ _ｉ（ｔ））の関数となっている。その温度差が大きくなるほど、流入熱量ｑ_１が増える。流入熱量ｑ_１の算出には、シリンダ内物質の熱伝導率［Ｗ／（ｍ・℃）］などが用いられる。
ｑ_２は、座標ｘ（ｘ＝ｉ×Δｘ）における微小領域から、後方（図４中右側）の微小領域に流れ出す単位時間当たりの流出熱量［Ｗ］を表す。流出熱量ｑ_２は、微小領域間の温度差（Ｔ^ｆｌ _ｉ（ｔ）−Ｔ^ｆｌ _ｉ＋１（ｔ））の関数となっている。その温度差が大きくなるほど、流出熱量ｑ_２が増える。流出熱量ｑ_２の算出には、シリンダ内物質の熱伝導率［Ｗ／（ｍ・℃）］などが用いられる。
ｑ_３は、座標ｘ（ｘ＝ｉ×Δｘ）における微小領域に、シリンダ１１から単位時間当たりに流れ込む熱量［Ｗ］を表す。この熱量ｑ_３は、シリンダ内物質とシリンダ１１との温度差（Ｔ_ｉ,ｎ（ｔ）−Ｔ^ｆｌ _ｉ（ｔ））の関数となっている。その温度差が大きくなるほど、熱量ｑ_３が増える。熱量ｑ_３の算出には、シリンダ内物質とシリンダ１１との間の熱伝達係数［Ｗ／（ｍ^２・℃）］などが用いられる。

In the above formula (2), T ^fl _i (t) is the temperature [° C.] at time t in the minute space at the coordinate x = i × Δx, ρ _in is the density of the substance _in the cylinder [kg / m ³ ], and c _in is It represents the constant pressure specific heat [J / kg] of the substance in the cylinder.
q ₁ represents the inflow heat quantity [W] per unit time flowing from the front (left side in FIG. 4) minute area into the minute area at the coordinate x (x = i × Δx). The inflow heat quantity q ₁ is a function of the temperature difference (T ^fl _i−1 (t) −T ^fl _i (t)) between the minute regions. The temperature difference increases, the inflow amount of heat q ₁ increases. For the calculation of the inflow heat quantity q ₁ , the thermal conductivity [W / (m · ° C.)] of the substance in the cylinder is used.
q ₂ represents the amount of heat [W] per unit time flowing out from the minute region at the coordinate x (x = i × Δx) to the minute region on the rear (right side in FIG. 4). Outlet heat _{q 2} is a function of the temperature difference between the micro areas _{^{(T fl i (t) -T}} fl i + 1 (t)). The temperature difference increases, the outflow amount of heat q ₂ is increased. For the calculation of the amount of heat released q ₂ , the thermal conductivity [W / (m · ° C.)] of the substance in the cylinder is used.
q ₃ represents the amount of heat [W] flowing from the cylinder 11 per unit time into a minute region at the coordinate x (x = i × Δx). The amount of heat q ₃ is a function of the temperature difference (T _{i, n} (t) −T ^fl _i (t)) between the cylinder internal material and the cylinder 11. The temperature difference increases, increases the amount of heat q _3. For the calculation of the amount of heat q ₃ , a heat transfer coefficient [W / (m ² · ° C.)] between the substance in the cylinder and the cylinder 11 is used.

Temperature ^T _fl m of the rear end of the cylinder material (coordinate x = m × Δx) (t ) is maintained at substantially the same temperature as the outside air temperature _{T a} by the cooling device 30. Therefore, a temperature fixing condition is given as a boundary condition between the rear end of the cylinder material and the outside air. That is, the equation T ^fl _m (t) = T _a is established. The temperature ^T _fl m of the rear end of the cylinder material (t) may be maintained at a higher predetermined temperature _{T c (T c> T a} ) than the outside air temperature _{T a.}

On the other hand, a heat flux boundary condition is given as a boundary condition between the front end (coordinate x = 0) of the substance in the cylinder and the outside air. Therefore, the rate of temperature rise (one-time differentiation of temperature T ^fl ₀ (t)) at the front end (coordinate x = 0) of the substance in the cylinder is the temperature of the minute region, the temperature of the minute region adjacent to the minute region, the outside air heat transfer coefficient between the temperature T _a, cylinder material and the ambient air of ^{[W / (m 2 · ℃} )], the heat transfer coefficient between the cylinder material and cylinder ^{[W / (m 2 · ℃} )] It is determined by.

FIG. 5 is an explanatory diagram of a formula representing heat inflow / outflow in the heating source according to the embodiment of the present invention. Expression for the inflow and outflow of heat in the heat source H _k, for example the following formula (3) is expressed by the like. In Equation (3), for simplification of the formula, in each heating source H _k, the temperature distribution is as uniform.

上記式（３）中、Ｔ_ｈｋ（ｔ）は加熱源Ｈ_ｋの時刻ｔの温度［℃］、Ｔ_ａは外気の温度［℃］、Ｃ_ｋは加熱源Ｈ_ｋの熱容量［Ｊ／℃］、Ｚ_ｋは加熱源Ｈ_ｋの電気抵抗［Ω］、Ａ_ｋは加熱源Ｈ_ｋの外気との接触面積、ｈ_ｋは加熱源Ｈ_ｋと外気との間の熱伝達係数［Ｗ／（ｍ^２・℃）］、Ｖ_ｋ（ｔ）は時刻ｔにおける加熱源Ｈ_ｋの電圧［Ｖ］を表す。
Ｖ_ｋ（ｔ）^２／Ｚ_ｋは加熱源Ｈ_ｋの出力（単位時間当たりの発熱量）［Ｗ］、ｈ_ｋ×Ａ_ｋ×（Ｔ_ｈｋ−Ｔ_ａ）は加熱源Ｈ_ｋから外気に逃げる単位時間当たりの放熱量［Ｗ］、Ｑ_ｋは加熱源Ｈ_ｋからシリンダ１１に流れ込む単位時間当たりの入熱量［Ｗ］を表す。
熱伝達係数ｈ_ｋは、加熱源Ｈ_ｋと外気との温度差（Ｔ_ｈｋ（ｔ）−Ｔ_ａ）の関数であってよい。その温度差が大きくなるほど、熱伝達係数_ｈｋが大きくなる。
入熱量Ｑ_ｋは、加熱源Ｈ_ｋと、シリンダ１１との温度差（Ｔ_ｈｋ（ｔ）−Ｔ_ｉ,０（ｔ））の関数となっている。その温度差が大きくなるほど、入熱量Ｑ_ｋが増える。但し、ｉは、シリンダ１１の複数の微少領域のうち、加熱源Ｈ_ｋと接する微少領域の座標を表す整数である。

In the above formula (3), T _hk (t) is the temperature [° C.] of the heating source H _k at time t, T _a is the outside air temperature [° C.], and C _k is the heat capacity of the heating source H _k [J / ° C.]. , _{Z k} is the electrical resistance of the heating source _{H k [Ω], a k} is the area of contact with the outside air of the heating source _{H k, h k} is the heat source _{H k} the heat transfer coefficient between the outside air [W / (m ² · ° C.)], V _k (t) represents the voltage [V] of the heating source H _k at time t.
^{_{V k (t) 2 / Z}} k is the output of the heat source _{H k} (the amount of heat generated per unit _{time) [W], h k ×} A k × (T hk -T a) escapes to the outside air from the heating source _{H k} The amount of heat released per unit time [W], Q _k represents the amount of heat input [W] per unit time flowing into the cylinder 11 from the heating source H _k .
The heat transfer coefficient h _k may be a function of _a temperature difference (T _hk (t) −T _a ) between the heating source H _k and the outside air. As the temperature difference increases, the heat transfer coefficient _hk increases.
The amount of heat input Q _k is a function of the temperature difference (T _hk (t) −T _{i, 0} (t)) between the heating source H _k and the cylinder 11. The temperature difference increases, the heat input Q _k increases. However, i is an integer representing the coordinates of the minute region in contact with the heating source H _k among the plurality of minute regions of the cylinder 11.

Thus, the heat conduction equation of the cylinder 11 (Equation (1)), the heat conduction equation of the material in the cylinder (Equation (2)), and the equation (Equation (3)) representing the inflow and outflow of heat in each heating source _Hk . ) Etc., a heat transfer model is created.

The heat transfer model may be reduced in order to reduce calculation time. For example, the heat conduction equation (equation (1)) of the cylinder 11 and the heat conduction equation (equation (2)) of the substance in the cylinder are linear equations. Can reduce the dimensions. Meanwhile, expression for the inflow and outflow of heat in the heat source H _k (Equation (3)) is because it is non-linear equation, and because originally is a low-dimensional, it is not necessary to dimension reduction.

The estimation unit 63 calculates the temperature T _{i, j} (t) at an arbitrary position of the cylinder 11 at the predetermined time by inputting the output [W] of each heating source H _{k at} the predetermined time to the heat transfer model. Since the number (m + 1) × (n + 1) of the minute regions in the cylinder 11 is significantly larger than the number (four in FIG. 2) of the temperature sensors S _k (k = 1, 2, 3, 4 in FIG. 2), the cylinder 11 The detailed temperature distribution at. The output of each heating source H _k may be input to the heat transfer model as an output waveform from the initial time (t = 0) to a predetermined time.

In addition, the estimation unit 63 inputs the output [W] of each heating source H _{k at} a predetermined time to the heat transfer model, whereby the temperature T ^fl _i (t) of the minute region of the substance in the cylinder at the predetermined time, the predetermined time The temperature T _hk (t) of each heating source H _k can also be calculated. Therefore, the detailed temperature distribution inside the cylinder 11 and the temperature of each heating source _Hk are also known. The output of each heating source H _k may be input to the heat transfer model as an output waveform from the initial time (t = 0) to a predetermined time.

Since the heat transfer model is a differential equation, by giving initial values T _{i, j} (t = 0), T ^fl _i (t = 0), T _hk (t = 0), T _{i, j} (t ), T ^fl _i (t), T _hk (t). The initial time (t = 0) may be, for example, the temperature rise start time of the cylinder 11, and the initial values T _{i, j} (t = 0), T ^fl _i (t = 0), T _hk (t = 0) it may be the same as the temperature _{T a.}

Incidentally, the initial value ^{_{T i, j (t = 0}} ), T fl i (t = 0), T hk (t = 0) may be any known, not be the same as the outside air temperature _{T a} Good. That is, the initial time (t = 0) may not be the temperature rise start time of the cylinder 11.

Estimation unit 63, an output of the heating source H _k to be input to the heat transfer model [W], may be detected due to power meter P _k of the heating source H _{k (see} FIG. 2). Based on the actual output waveform of the heating source H _k, so to estimate the temperature, estimation accuracy is good.

Further, the estimating unit 63, the output of the heating source H _k to be input to the heat transfer model, the control constant of the feedback control model of the heating source H _k (e.g. PID control model) (e.g. proportional gain, integral gain, differential gain) to You may calculate based on. First, the estimation unit 63 determines the heating source H _k at a time t + Δt slightly later than the time t from the deviation between the temperature T _{i, j} (t) at the measurement position of the temperature sensor S _k and the set temperature and the control constant. Predict output. Then, the estimation unit 63, an output of the heating source H _k predicted entered the heat transfer model predicts the temperature of the measurement position of the temperature sensor S _k at time t + Delta] t. Thus, by repeating the prediction of the output of the heating source H _k, the prediction of the temperature, the estimating unit 63 is not only current temperature and a past temperature, it is possible to predict the future temperature.

Note that the output of the heating source H _k up to now may be detected by the wattmeter P _k , and the future output of the heating source H _k may be predicted using the control constant of the feedback control model.

The estimation unit 63 may monitor whether the estimated temperature at the predetermined position is within a predetermined range. For example, the estimation unit 63 estimates the future temperature T _{i, j} (t) at the measurement position of the temperature sensor _Sk , and the estimated temperature is within a predetermined range including the set temperature (for example, within a predetermined range centered on the set temperature). ). The quality of the set temperature can be determined in advance based on the monitoring result. The estimation unit 63 determines that the set temperature is good when the estimated temperature is within the predetermined range, and determines that the set temperature is not good when the estimated temperature is not within the predetermined range.

As a result of monitoring, the estimation unit 63 may change the set temperature of the cylinder 11 when the estimated temperature at the predetermined position is not within the predetermined range. Based on the changed set temperature, the estimation unit 63 estimates a future temperature T _{i, j} (t) at the measurement position of the temperature sensor _Sk , and monitors whether the estimated temperature is within a predetermined range. The set temperature can be optimized by repeatedly changing the set temperature so that the estimated temperature falls within the predetermined range. The set temperature may be changed within a predetermined range according to molding conditions (for example, the type of resin). The set temperature may be optimized before the temperature increase of the cylinder 11 is started.

  The estimation unit 63 outputs a warning when the estimated temperature at the predetermined position is not within the predetermined range as a result of monitoring. The warning is issued by a display unit 71, a warning buzzer, a warning lamp, etc., which will be described later.

Based on the estimated temperatures T _{i, j} (t), T ^fl _i (t), and T _hk (t), the estimation unit 63 _calculates the heat flux [J / (m ² · s at a predetermined position at a predetermined time]. )], Or the amount of heat [W] per unit time passing through a predetermined position at a predetermined time may be estimated. The positions for estimating the heat flux and the heat amount are, for example, the interface between the heating source H _k and the outside air, the interface between the heating source H _k and the cylinder 11, the interface between the cylinder 11 and the cooling device 30, and the cylinder 11 and the outside air. Examples thereof include an interface and an interface between the substance in the cylinder and the cylinder 11. The position for estimating the heat flux and the heat quantity may be the interface between the minute regions in the cylinder 11 or the interface between the minute regions inside the cylinder 11.

  The estimation unit 63 may monitor whether or not the estimated heat flux or heat amount exceeds a predetermined value, and may output a warning when the estimated heat flux or heat amount exceeds a predetermined value.

  As shown in FIG. 2, the injection molding machine 10 further includes a display unit 71 that displays a value representing heat transfer based on the estimation result of the estimation unit 63. Since the estimation unit 63 estimates the detailed temperature, heat flux, amount of heat, and the like, the display unit 71 can display the temperature, heat flux, amount of heat, and the like at the position where the user is interested. The display unit 71 is composed of a liquid crystal display, for example. The display on the display unit 71 is controlled by the controller 60.

The display unit 71 has a temperature distribution at a predetermined time, a temporal change in temperature at a predetermined position, a heat flux [J / (m ² · s)] at a predetermined time and a predetermined position, and a predetermined value at a predetermined time as values representing heat transfer. At least one of the amount of heat [W] per unit time passing through the position may be displayed. The predetermined time may be present, past, or future. Data of a plurality of times may be displayed at the same time.

The temperature distribution at a predetermined time may be displayed as a graph in which, for example, the x coordinate or the y coordinate is taken as one axis and the temperature is taken as the other axis. The user who sees the display unit 71 can visually understand the temperature gradient and can recognize the heat moving direction. As the temperature distribution, for example, the temperature distribution of the cylinder 11 and the temperature distribution inside the cylinder are displayed. Since the number (m + 1) × (n + 1) of the minute regions in the cylinder 11 and the number (m + 1) of the minute regions in the cylinder 11 are larger than the number of the temperature sensors _Sk , the detailed temperature distribution is known. The direction of the temperature distribution may be either the axial direction of the cylinder 11 or the radial direction of the cylinder 11.

  The time change of the temperature at the predetermined position may be displayed, for example, as a graph in which time is taken on one axis and temperature is taken on the other axis. The user who sees the display unit 71 can visually understand the response at the time of temperature rise and the stability at the time of steady state.

The heat flux [J / (m ² · s)] at a predetermined time and a predetermined position may be displayed as a bar graph, for example. The user who sees the display unit 71 can visually understand the amount of heat movement due to the temperature gradient and the direction of movement. The heat flux or the like may be displayed as a numerical value, and the display form is not particularly limited.

Of heat [W] is per unit time through a predetermined position in a predetermined time may be the total output [W] at the same time as the display of a plurality of heating sources H _k, the total output of the plurality of heating sources H _k [W] a It may be displayed as a reference ratio [%]. Users who viewed the display section 71 can be understood and heating efficiency of the heating source H _k. The amount of heat displayed on the display unit 71 includes, for example, a heat release amount [W] per unit time that escapes from the heating source H _k and the cylinder 11 to the outside air, and a heat input amount per unit time that is supplied from the heating source H _k to the cylinder 11. [W], heat release amount [W] per unit time escaping from the cylinder 11 to the cooling device 30, and heat input amount [W] per unit time supplied from the cylinder 11 to the in-cylinder material.

  Moreover, the injection molding machine 10 may further include an input unit 72 that receives a user input operation, as shown in FIG. The controller 60 controls display on the display unit 71 based on a user command input via the input unit 72. User convenience is good.

  For example, the display unit 71 may display a value representing heat transfer at a position specified by the user using the input unit 72. The method for specifying the position is not particularly limited. For example, the user may input position coordinates (x, y), or one or more of a plurality of registered candidate positions (for example, a cylinder inner peripheral surface, a cylinder interior, a temperature sensor measurement position, etc.). The position may be selected and input.

  The display unit 71 may display a value representing heat transfer at the time designated by the user using the input unit 72. The way of specifying the time is not particularly limited. For example, the user may input a time based on the current time, or select one or more times from among a plurality of registered candidate times (for example, the current time, one hour before, one hour after). You may select and input. The default time when the user does not specify the time may be the current time. Various data can be displayed in real time.

  In addition, although the display part 71 and the input part 72 of this embodiment are provided separately, you may provide integrally, for example as a touchscreen.

  Although the embodiment of the injection molding machine has been described above, the present invention is not limited to the above embodiment and the like, and various modifications and improvements can be made within the scope described in the claims.

  For example, in the heat conduction equation (2) of the substance in the cylinder of the above embodiment, for simplification of the equation, the inside of the cylinder 11 is partitioned in the axial direction of the cylinder 11 as shown in FIG. Although not divided into two, it may be divided also in the radial direction of the cylinder.

Further, in Formula (3) representing the inflow and outflow of heat in the heat source Hk of the above embodiment, for simplicity of expression, as shown in FIG. 5 does not partition the heating source H _k into a plurality of small areas However, it may be partitioned.

  The cylinder of the above embodiment is of a screw / inline type, but may be of a plunger / prepa type or a screw / prepa type. In the pre-plastic method, the resin melted in the plasticizing cylinder is supplied to the injection cylinder, and the molten resin is injected from the injection cylinder into the mold apparatus. In the case of the pre-plastic method, the cylinder may be either a plasticizing cylinder or an injection cylinder.

10 injection molding machine 11 cylinder 12 the nozzle 13 screw 30 cooling device 60 controller 63 estimating unit 71 display unit 72 input unit _H 1 to H ₄ heat source _Z 1 to Z ₄ zones _S 1 to S ₄ Temperature sensor

Claims (10)

A cylinder to which the molding material is supplied;
A heating source for heating the cylinder;
Estimating the temperature at any location in the cylinder using a heat transfer model based on the heat transfer equation of the cylinder, the heat transfer equation of the material in the cylinder, and an equation representing heat inflow and outflow in the heating source With
The estimation unit inputs an output of the heating source at a predetermined future time to the heat transfer model, and predicts a temperature at an arbitrary position in the cylinder at the predetermined future time. The estimation unit predicts an output of the heating source at the future predetermined time based on a control constant of a feedback control model of the heating source, inputs the predicted output to the heat transfer model, and The injection molding machine according to claim 1 , wherein a temperature at an arbitrary position in the cylinder at a time is predicted . A temperature sensor for measuring the temperature of the cylinder;
The estimator is based on a deviation between a temperature at a measurement position of the temperature sensor at a first time and a set temperature, and a control constant of a feedback control model of the heating source. predicting the output of the heating source in time, and inputs the output predicted to the heat transfer model predicts the temperature at an arbitrary position in the cylinder of the second time, according to claim 1 or 2 Injection molding machine. The injection molding machine according to any one of claims 1 to 3 , further comprising a display unit that displays a value representing heat transfer based on an estimation result of the estimation unit. The display unit represents the temperature distribution at a predetermined time, the temporal change in temperature at a predetermined position, the heat flux at the predetermined time and the predetermined position, and the amount of heat per unit time passing through the predetermined position at the predetermined time as values representing heat transfer. The injection molding machine according to claim 4 , wherein at least one of them is displayed. It further includes an input unit that accepts user input operations,
The injection molding machine according to claim 4 or 5 , wherein the display unit displays a value representing heat transfer at a position designated by the user at the input unit and / or at a time designated by the user at the input unit. The estimation unit estimates a temperature of a predetermined position to monitor whether within a predetermined range, an injection molding machine according to any one of claims 1-6. The injection molding machine according to claim 7 , wherein the estimation unit changes a set temperature of the cylinder when the estimated temperature is not within a predetermined range. The injection molding machine according to claim 7 or 8 , wherein the estimation unit outputs a warning when the estimated temperature is not within a predetermined range. The estimation unit inputs an output of the heating source at a predetermined time to the heat transfer model, and further estimates the temperature of the substance in the cylinder at the predetermined time and the temperature of the heating source at the predetermined time. The injection molding machine according to any one of 1 to 9 .

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