JPH11333894A - Injection molding machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To control a clamping force of a mold of an injection molding machine to a minimum corresponding to an injection pressure of a molding material. SOLUTION: A distance (h) corresponding to a gap which is proportional to a leakage amount Q leaked from a parting face 18 is found. A surface pressure is calculated from a value of the distance (h) corresponding to a gap and an input value of a surface roughness Ra of the parting face 18. A total pressure of the parting face 18 is calculated from the surface pressure and a dwell pressure, and a minimum clamping force is calculated from an internal pressure of a molding cavity 19. Thereby the clamping force is controlled.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an injection molding machine for molding a rubber or resin material. In particular, the present invention relates to an injection molding machine capable of selecting a mold clamping force of a molding die.

[0002]

2. Description of the Related Art There is an injection molding machine 50 shown in FIG. 10 as prior art relating to the present invention. In FIG. 10, the injection molding machine 50 includes a driving device 51, an injection device 52, and a mold clamping device 53.

[0003] In FIG.
0 is attached. One mold 60a of the split mold 60
Is attached to the fixing die plate 54, and the other die 60b of the split die 60 is
5 attached.

[0004] The moving die plate 55 is provided with a booster ram 5.
6 to reciprocate. The moving die plate 55 is guided by four guide rods 57 fixed to the booster ram 56 and the fixing die plate 54. The split mold 60 is clamped and opened by the moving die plate 55 and the fixing die plate 54 moved by the booster ram 56, and is formed by injection of a molding material from the injection device 52 and formed by releasing the mold. An article is formed.

[0005]

The conventional mold clamping device 5
In No. 3, the mold clamping force was calculated by the product projected area × holding pressure × safety factor irrespective of the size of the molded item, so the booster ram 56 for clamping more than necessary according to the magnitude of the safety factor.
Power loss. Further, both split molds 60a,
There is a problem that wear is large due to excessive pressing of the parting surfaces 61, 61 of the 60b.
This is a cause of the generation of burrs B from the parting surfaces 61, 61 of 60b.

Further, in the production of a new molded item, a production test of the molded product is carried out with a new split mold 60 to determine whether or not burrs are generated due to leakage of molding material from the parting surfaces 61, 61. I had to judge. For this reason, adjustment of the molding conditions and determination of the quality of the molded product must be repeated, resulting in a long setup time.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and a technical problem of the present invention is that a molding material does not leak from a parting surface of a molding die during injection molding. An object of the present invention is to calculate a minimum mold clamping force and output it to a hydraulic pump of a mold clamping device to prevent burrs.

Another object of the present invention is to prevent the abrasion of the parting surface of the mold, to prolong the life of the mold, and to prevent the occurrence of burrs during molding.

Furthermore, the mold clamping force in molding is tested to prevent inefficient setup work such as adjustment of molding conditions and selection of a molding apparatus from burr leakage, and the minimum die is automatically set according to set conditions. An object of the present invention is to calculate a clamping force, control the pressure of a mold clamping device so as to obtain the mold clamping force, improve the efficiency of the setup work, and reduce the running cost.

[0010]

SUMMARY OF THE INVENTION An injection molding machine according to the present invention has been made in view of the above problems, and
The technical means is configured as follows. That is,

According to a first aspect of the present invention, there is provided an injection molding machine, comprising: a mold clamping device (2) for clamping a molding die (15) having a molding cavity (19); and a control for controlling the mold clamping device (2). An injection molding machine having a device (24), wherein the control device (24) removes the molding material (M) from between the parting surfaces (18) of the molding die (15). A gap equivalent distance (h) proportional to the corresponding leakage amount (Q) is calculated and obtained from the value of the gap equivalent distance (h) and the input value of the surface roughness (Ra) of the parting surface (18). The surface pressure (δ) of the parting surface (18) is calculated, the entire surface pressure (δ × A) of the parting surface (18) is calculated from the surface pressure (δ), and the holding pressure of the molding cavity (19) is calculated. Calculates the internal pressure (Pc × S) in the mold clamping direction of the molding cavity (19) from the total pressure (δ × A) In addition the inner pressure (Ps × S) is used to input and calculate minimum mold clamping force of the mold clamping device (2) to (F).

According to a second aspect of the present invention, there is provided an injection molding machine for injecting a molding material (M) from an injection nozzle.
A molding cavity (19) for molding the molding material (M) injected from the injection section (40); and a parting surface (1).
8), a pressure sensor (31) for detecting a holding pressure in the molding die (15), and a molding die (1).
5) a mold clamping device (2) for clamping the parting surface (18); and a control device (24) for controlling the clamping force of the mold clamping device (2). Calculates the gap equivalent distance (h) proportional to the leakage amount (Q) of the input value corresponding to the allowable burr of the molding material (M) between the parting surfaces (18). The surface pressure (δ) of the parting surface (18) calculated from the surface roughness (Ra) of the parting surface (18) of the input value is obtained, and the parting surface (δ) obtained from the surface pressure (δ) is obtained. The minimum mold clamping force (F) is calculated from the overall pressure in 18) and the internal pressure in the mold clamping direction of the molding cavity (19) calculated from the holding pressure (Pc) from the pressure sensor (35), and the minimum mold clamping force is calculated. The signal of (F) is input to the mold clamping device (2) to clamp the mold.

According to a third aspect of the present invention, the surface pressure (δ) of the parting surface (18) for calculating the minimum mold clamping force (F) of the mold clamping device (2) is reduced. The correlation between the gap equivalent distance (h), the parting surface roughness (Ra) and the surface pressure (δ) of the parting surface (18) in (15) is calculated based on data actually measured in advance. Have been.

[0014]

The injection molding machine of the present invention inputs molding die information data information, molding material characteristic data information, and a threshold value of the amount of molding material leakage forming allowable burrs to the control device, and outputs the surface of the parting surface. The pressure is calculated, the minimum clamping force of the mold clamping device is calculated from the surface pressure, and the control device controls the mold clamping device based on the signal of the minimum clamping force. For this reason, the parting surface of the molding die is not pressed more than necessary, which contributes to energy saving of the power part of the mold clamping device and also prevents wear of the parting surface. Further, high-speed mold clamping of the mold clamping device is enabled, and the molding cycle can be shortened. That is, since the time range until the joining of the parting surfaces is short, the molding cycle can be shortened by about 30%.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an injection molding machine according to the present invention will be described in detail with reference to the drawings.

FIG. 1 is a sectional view of an injection molding machine 1 according to the present invention. FIG. 3 shows a mold clamping device 2 of the injection molding machine 1.
It is an expanded sectional view of the shaping | molding die 15 attached to.

In FIG. 1, a molding die 15 shown in FIG. 3 is provided between a fixing die plate 3 and a moving die plate 4.
The divided right die 16 of the molding die 15 is attached to the fixing die plate 3, and its left die 17 is attached to the moving die plate 4.

The moving die plate 4 is configured to be reciprocated by the ram 5 while being guided by the fixing die plate 3 and four guide rods 6 attached to the ram 5 serving as a driving unit. The moving die plate 4 is of a type that is moved by being pressed by a piston rod 7 provided on the ram 5, and is a so-called direct pressure type. A toggle type can be adopted instead of the direct pressure type. As the molding material M, a rubber material or a resin material is used.

The injection molding machine 1 provided with the mold clamping device 2 comprises:
The injection unit 40 is provided on the right side, and the injection unit 4
A control device 24 is provided for actuating 0. In addition,
FIG. 1 is a cross-sectional view showing a state in which a hood-like material made of a rubber material is introduced into a supply port 42 from the tip, melted, and injected into the molding cavity 19. When the molding material M is a resin, it becomes a pellet and is supplied from a popper.

The mold clamping device 2 is operated by operating a ram 5 by a power unit 8 of a hydraulic pump. This ram 5
The molding die 15 is clamped by the
The molding material M is molded by being injected into the molding cavity 19 of the molding die 15.

The injection part 40 is formed by the injection motor 41 inside the screw cylinder 47 and the hydraulic motor 44a.
As a result, the molding material M is brought into a molten state by being rotated, and the molding material M melted by being advanced by the hydraulic cylinder 44b is injected into the molding cavity 19 of the molding die 15. It should be noted that even if the injection is completed and the molding cavity 19 is filled with the molding material, the molding material contracts, so that the injection pressure needs to be maintained for a certain time.

A hydraulic motor 44a for driving this injection process
The hydraulic cylinder 44b is operated via a power unit 45 and a servo valve 46 controlled by a command from the control unit 24. Then, in the injection step, while being injected by the injection pressure and after filling the molding cavity 19, the pressure in the molding cavity 19 is maintained for a certain period of time, and the holding pressure to replenish the contraction of the molding material M is maintained. Do.

Next, the mold clamping device 2 operates according to a command from the control device 24. This control device 24 is configured as shown in FIG. When the injection process enters the pressure holding state, the pressure sensor 31 mounted in the injection nozzle 43 (this pressure sensor 31 can also be mounted in the molding cavity 19) inputs the data of the pressure holding to the control device 24 as a signal. I do.

As shown in FIG. 2, the control device 24 includes a PC
(Programmable controller) arithmetic processing unit (CP
U) 240, memory 242, A / D exchanger 244, I /
An O device 246 and a D / A exchanger 243 are provided.
The analog pressure signal input from the I / F 23 is converted into a digital pressure signal by the A / D exchanger 244. Similarly, an analog pressure signal input from the I / F 22 is converted into a digital pressure signal by the A / D exchanger 244. CPU 240 is memory 2
The control program stored in 42 is operated to perform a control operation described later. The result is the D / A exchanger 243
Is output to the I / F 21 as a digital type servo valve 9 drive signal. The setting unit (programming tool) 25 inputs data such as a type information database, a material property database, a threshold value database, and a facility capacity database into the memory unit 242.

The hydraulic pump, which is the power unit 8 of the mold clamping device 2, is configured so that the control device 24 can control the mold clamping force. That is, the pressure of the hydraulic pump serving as the power unit 8 can be controlled by inputting the data to the memory unit 242 from the setting device (programming tool) 25 of the control device 24. The control device 24 is configured so that the CPU 240 and the memory unit 242 can calculate the minimum clamping force described later. Then, the processed information is transmitted to the power unit 8 (hydraulic pump) to control the minimum mold clamping force.

Next, a method of calculating the minimum mold clamping force of the mold clamping device 2 will be described. First, at the time of molding by the injection molding apparatus 1, it is prevented that the molding material M protrudes from a mold opening surface where the right mold 16 and the left mold 17 of the molding die 15 are joined, that is, a so-called parting surface 18, and burrs are generated. Therefore, the mold clamping device 2 is clamped by the mold clamping force F by the pressure of the ram 5. The minimum mold clamping force F is given by the following equation (2), where δ is the surface pressure of the parting surface 23, A is the area thereof, Pc is the molding material pressure (holding pressure) in the cavity, and S is the projected area of the molded product. It is represented by

[0027]

## EQU1 ## F ≧ PcS + δA

When F becomes smaller than the value of the right expression in the equation 1,
Leaks that form burrs will occur. That is, if the value on the right side of Equation 1 is known, the minimum mold clamping force F for preventing the leakage of the molding material M is calculated, and a control command can be issued to the power unit 8 of the ram 5. Since Pc is the holding pressure, the right side of Equation 1 can be detected by providing the second pressure sensor 31 in the nozzle 43 of the injection unit 40. Further, the area A of the parting surface can be determined from the mold 15. Further, the molded product projected area S can be similarly known from the molding die 15. That is, if the surface pressure δ of the parting surface 18 can be known, the minimum required clamping force F can be calculated and the output of the power unit 8 of the clamping device 2 can be controlled to the optimum pressure.

Now, the surface pressure δ of the parting line will be considered. When the mold 15 is clamped by the injection molding machine 1 shown in FIG. 1, the function of the mold clamping force F and the strain ε of the mold is as shown in FIG. Pas mold 15 - the relationship between the strain ε of the surface pressure [delta] and the mold 15 of the coating surface 18 is seen to vary as a boundary surface pressure [delta] _1. That is, in the region A, the surface pressure δ and the strain ε do not follow the Hooke's law line a,
The rate of increase of the strain gradually decreases. On the other hand, in the region B, the rate of increase is constant and follows the Hooke's law line a. This region A is considered to be generated because the area of the parting surface is not constant. The cause is the parting surface 18
Is caused by the surface roughness Ra and undulation (flatness) of the surface pressure δ.

On the other hand, in the region B, the parting surfaces 18 of the left and right dies 16 and 17 are in close contact with no gap, and no leakage of the molding material M that generates burrs is observed. Conventionally, since molding was performed in the B region where the safety factor was increased, the mold was clamped with an excessive clamping force F, and the wear of the molding die and the energy loss of the power section 8 were increased.

Incidentally, it is also recognized that the molding material M does not always leak in the region A. For example, the parting surface 1 depends on the viscosity of the molding material M.
8 shows that the surface pressure of the parting surface 18 from which the molding material M leaks is different. That is, the molding material M
When the viscosity is high, there is a tendency that the molding material M does not leak even if the surface pressure δ of the parting surface is small.

FIG. 5 theoretically and experimentally finds characteristic factors for determining the surface pressure δ of the parting surface 18. The minimum mold clamping force F can be calculated by replacing the surface pressure δ of the parting surface 18 with the leakage that generates burrs and compiling a database of these characteristic factors.

Then, it is found that the value of the surface pressure δ ₁ of the parting surface 18 in FIG. 4 is the minimum clamping force F of the clamping device 2. FIG. 6 shows the state of the parting surface 18 when the mold 15 is clamped by the mold clamping apparatus 2 shown in FIG. FIG. 6 is a conceptual sectional view showing the parting surface 18 of the molding die 15 microscopically.

Considering the state of the parting surface 18 when the parting surface 18 in FIG. 6 is clamped with a certain clamping force,
Although it depends on the shape of the parting surface 18 and the mold clamping force, microscopically, the parting surface 18 is dotted with countless minute gaps 19. Assuming that the equivalent distance is replaced by a gap equivalent distance h μm as shown in FIG. 7, the replacement of the molding material M with the gap equivalent distance h in consideration of the burr leakage is based on the amount of burr leakage. It can be calculated theoretically. In other words, the rubber flow rate flowing through the minute gap is
It is expressed by the following equation (3). Then, when the gap-equivalent distance h in the equation (2) is calculated from the measured leakage amount Q that becomes a burr, this becomes the gap-equivalent distance h. FIG. 7 is a conceptual cross-sectional view showing the gap equivalent distance h.

[0035]

(Equation 2) However, Q = leakage amount that causes burrs L = parting surface length W = parting surface width ΔP = rubber pressure h = gap m, n = viscosity index of material

That is, if the gap-equivalent distance h in a certain molding state is known, the leakage amount Q serving as a burr at that time can be estimated. If this value is less than the threshold value (reference value), it means that "there is no leakage of burr molding". At this time, the mold clamping force of the molding die 15 is the minimum mold clamping force F.
It is.

Next, FIG. 8 shows a state of a certain material, for example, S55C.
The relationship between the gap equivalent distance h in the material forming die 15 and the surface pressure δ of the parting surface was actually measured by an experiment.
In FIG. 8, if the surface pressure δ of the parting surface 18 and the surface roughness Ra of the parting surface 18 at the time of molding with the molding die 15 are known, the gap-equivalent distance h becomes δ ₁ and h ₁ . It can be calculated from the coordinates. And the viscosity index m of the molding material,
By substituting n and the gap-equivalent distance h into the equation (2),
The relationship is such that the amount of leakage Q, which is a burr, can be calculated. This proportional relationship between Q and h (Equation 2) can be calculated by other methods. For example, a molding die 15 with a certain No. is actually measured for each molding material M to obtain a proportional relational expression between Q and h, and the set value of the leak amount Q is substituted into this proportional relational expression to obtain a gap equivalent distance h. You can also ask.

That is, in the molding die 15 of a certain material, the leakage amount Q which becomes a burr below the threshold value is measured. And
The amount of leakage, Q, which becomes a burr, is substituted into the equation (2), and a number other than h is also measured. By substituting this value, the gap equivalent distance h can be obtained. FIG.
From the data, the surface pressure δkgf / mm ² of the parting surface 18 corresponding to the gap equivalent distance h is obtained. This surface pressure δ
Is obtained, the minimum mold clamping force F is obtained by substituting δ into the equation (1).

FIG. 9 is a flowchart for calculating the minimum mold clamping force F of the injection molding machine 1.

[Step 1] In step 1, the injection unit 40
, The molding conditions from the control device 24 are input. First, the NO of the mold 15 is input. Then, at least the molding temperature and the holding pressure are input. This is the molding condition. Also, the characteristics of the molding material are input.

[Step 2] From the mold information database, the material (hardness) of the mold, the size of the projected area S of the mold cavity 19 in the mold clamping direction, the dimension of the area of the parting surface 18 and the size of the parting surface 18 The surface roughness Ra is input.
Also, a viscosity index for each temperature is input from the material property database. Further, a failure boundary value of the leakage amount Q of burr formation is input from the database of the failure threshold value of the burr formation leakage amount. This input value is a value obtained by actually measuring each molding die and finding a threshold value of the leakage amount Q at the boundary δ ₁ between the region A and the region B in FIG. A set value of the formation leakage amount Q is input (for example, the JIS burr leakage amount of the O-ring is 0.15 × 0.10 mm or less).

[Step 3] The surface pressure δkgf / mm ² of the parting surface 18 is calculated by the CPU based on the input data from the database of step 2 and the data of step 2. In this calculation, data from the database of (1) and (2) is input to the equation (2) to calculate a gap equivalent distance hμm.

[Step 4] Based on the correlation between the surface roughness Ra of the parting surface 18 and the surface pressure δ of the parting surface 18, the surface pressure of the parting surface 18 is obtained from the gap distance h obtained in step 3. δ (kgf / mm ² ) is determined.

[Step 5] The minimum mold clamping force F is calculated by substituting the surface pressure δ of the parting surface 18 into the equation (1) from the surface pressure δ of the parting surface 18 obtained in step 4. Then, it is output to the control device 24 as an input signal.

[Step 6] Next, the capacity (upper and lower limit output data) of the hydraulic output of the hydraulic pump which is the power unit of the driving unit 8 of the mold clamping device 2 is input from the equipment capacity database. Then, it was determined whether or not the minimum mold clamping force F obtained in step 4 was within the range of the hydraulic output capability, and if it was within the range, it was confirmed that molding was possible.

The power unit (hydraulic pump) 8 of the ram 5 of the mold clamping device 2 is controlled by controlling the minimum mold clamping force F obtained in the mold clamping force calculation flowchart by a PC connected to the control device 24 shown in FIG. Activate.

Next, the operation of the injection molding machine 1 shown in FIG. 1 will be described. First, the CPU 24 of the PC as the control device 24
0 and the information of the type information database, the material property database, and the threshold value database of the amount of burr formation leakage are input to the memory unit 242, and the gap equivalent distance h is calculated according to the equation
Is calculated, and the surface pressure δ of the parting surface 18 is obtained from the correlation between the gap equivalent distance h and the surface roughness Ra of the parting surface 18. Calculate F. The calculation of the mold clamping force is performed according to the procedure described in the flowchart of FIG.

Next, after the input signal of the minimum mold clamping force F is subjected to various signal arithmetic processing by the equipment of the control device 24, the output signal is outputted to the hydraulic pump which is the power unit 8 of the mold clamping device 2. Then, the mold clamping device 2 is controlled to operate with the minimum mold clamping force.

At the same time, the control device 2 supplies output signals to the power unit 45 and the servo valve 46 to control the injection molding of the injection unit 40. This control is performed by the CPU 240 of FIG.
/ Servo valve 46 in digital form via AC243
Is output to the I / F 21a as a drive signal of the I / F 21a. The injection unit 40 melts the molding material (rubber material) and injects and fills the molding cavity 19 of the mold 15 from the injection nozzle 43 at high speed and high pressure. The driving of the injection screw 41 for performing the injection filling is performed by the CPU 240 based on the input value stored in the memory unit 242. When the molding cavity 19 is filled with a rubber molding material, the driving of the injection screw 41 proceeds with the pressure being substantially constant. When this injection pressure is continued, burrs are generated in the molded product. Therefore, the pressure is switched to the holding pressure enough to replenish the molding material M.

The injection pressure and the holding pressure are detected by the second pressure sensor 31, and an analog pressure signal input from the I / F 23 is converted into a digital pressure signal by the A / DC 244. Then, it is checked whether or not the UPC corresponds to the value of δ in the equation (2). When the value is out of the range corresponding to the set δ value of Equation 2, the processed signal is input to the power unit 8 of the mold clamping device 2 to control the mold clamping force.

The control device 24 shown as an example in FIG.
This is the main part of C. The control unit 24 includes an arithmetic processing unit (CPU) 240 included in the computer, a memory unit 242, an A / DC 244, an I / O device 246, and a D / AC 24.
3 and a D / AC 243 for outputting to the injection unit 40. Then, the signal detected by the pressure sensor 31 is
While being input to the I / F 23, the analog type pressure signal is changed to a digital type pressure signal by the A / DC 244. Similarly, the drive unit 8 input from the I / F 22
Is converted to an analog type pressure signal by A / DC24.
At step 4, it is converted into a digital pressure signal.

The CPU 240 operates a control program based on the above-described mold clamping force data stored in the memory unit 242 to perform a mold clamping control operation of the mold clamping device 2. At the same time, the injection unit 40 performs the injection molding control operation by causing the CPU 240 to operate the injection control program stored together with the memory unit 242. As a result, a digital drive signal for the servo valve 9 is output via the D / AC 243 as I
/ F21 to control the mold clamping device 2. This control can also be used to increase the speed of the molding cycle. The ram 5 is also configured so that the ability of the mold clamping device 2 for the mold clamping force can be checked in the same manner as the second pressure sensor 31. Then, the mold clamping ability of the injection molding machine 1 can be automatically determined.

As described above, the mold clamping apparatus 2 of the present invention is designed so that the molding is performed with the minimum mold clamping force F within a range where the molding material does not leak from the parting surface 18 of the molding die 15. The cycle can be improved, and at the same time, the abrasion of the joining surface of the parting surface 18 of the mold 15 can be prevented.

Further, by providing NO to the molding die 15 and inputting data such as the gap equivalent amount h of the molding die 15 and the surface roughness Ra of the parting surface 18, the control device 2
According to 4, it can be determined without testing whether or not the mold is a mold that forms burrs.

Next, as a second embodiment, the driving unit 5
Is provided with a first pressure sensor 30. The first pressure sensor 30 measures the oil pressure in the ram of the drive unit 5, and the analog pressure signal input to the interface circuit (I / F) 22 is converted into a digital pressure signal by the A / DC 244. Is converted to And the CPU 24
If 0 indicates an abnormality in the mold clamping force of the mold clamping device 2, an error is transmitted.

Further, when the minimum clamping force F becomes larger than the maximum capacity of the mold clamping device 2, an error is transmitted in the same manner, and molding is performed to confirm the inability of the injection molding machine due to defective products. It is possible to prevent a complicated setup and defective molding.

Further, as a third embodiment, a second pressure sensor 31 is provided in the injection nozzle 43 of the injection section 40,
The holding pressure at the time when the molding material leaks from the parting surface 18 can be measured, and is input to the CPU 240 via the I / F 23 and the A / DC 244 so that the minimum clamping force F can be calculated. . The holding pressure can be set and input in advance, but can be directly input from the second pressure sensor 31 to automate the calculation. Further, the second pressure sensor 31 can be provided in the molding cavity 19.

[0058]

According to the injection molding machine of the present invention, the control unit finds the distance equivalent to the gap, calculates the parting surface pressure, and clamps the mold clamping unit with the minimum clamping force from the parting surface pressure. With such control, it is possible to prevent wear of the parting surface of the mold. At the same time, the occurrence of distortion of the mold can be prevented. And the effect of maintaining the durability of the mold can be expected.

Further, since the minimum mold clamping force shortens the time required for pressing the parting surface, the molding cycle time can be shortened and the productivity can be improved. At the same time, it can be expected to achieve energy saving of the power section of the mold clamping device.

Also, by directly calculating the internal pressure in the mold clamping direction in the molding cavity from the holding pressure during injection molding,
Since the data information of the other molding dies, the data information of the molding material, and the data information of the leakage amount, which is the allowable burr of the molding material, have already been input to the control unit, the minimum mold clamping force can be directly calculated by calculating this data. It is possible to calculate and input to the mold clamping device for control.

Since the surface pressure of the parting surface can be directly obtained from the distance equivalent to the gap and the surface roughness of the parting surface,
Since these data are input to the control device, it is possible to directly calculate various types of No. molds.

[Brief description of the drawings]

FIG. 1 is a sectional view of an injection molding machine of the present invention.

FIG. 2 is a configuration diagram centering on a CPU of a control device (PC) of the present invention.

FIG. 3 is a cross-sectional view of the mold of FIG.

FIG. 4 is a diagram showing a relationship between distortion of a mold according to the present invention and surface pressure of a parting surface.

FIG. 5 is a characteristic factor diagram of surface pressure of a parting surface according to the present invention.

FIG. 6 is a sectional view conceptually showing a minute gap caused by the surface accuracy of the mold according to the present invention.

FIG. 7 is a sectional view showing a distance equivalent to a gap of the mold of FIG. 6;

FIG. 8 shows a surface pressure of a parting surface, a distance equivalent to a gap, and a parting pressure.
It is a correlation diagram by actual measurement with a toting surface roughness.

FIG. 9 is a flowchart for calculating a minimum mold clamping force according to the present invention.

FIG. 10 is a sectional view of a conventional injection molding apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Injection molding machine 2 ... Mold clamping device 3 ... Fixing die plate 4 ... Moving die plate 5 ... Drive part (ram) 6 ... Guide rod 7 ... Piston Rod 8: Power section (hydraulic pump) 8a: Variable displacement pump 9: Servo valve 15: Mold 16: Right 17: Left 18: Parting surface (Mold division surface) 19 Mold cavity 21-23 I / F (interface) 24 Controller (PC) 240 CPU 242 Memory unit 244 A / DC 246 I / O device 248 D / AC 25 Setting device (programming tool) 30 First pressure sensor 31 Second pressure sensor 40 Injection unit 41 ... injection screw 42 ... supply port 43 ...・ Injection nozzle 44a ・ ・ ・ Hydraulic motor 44b ・ ・ ・ Hydraulic cylinder 45 ・ ・ ・ Power device 45a ・ ・ ・ Variable displacement pump 46 ・ ・ ・ Servo valve 47 ・ ・ ・ Screw cylinder 50 ・ ・ ・ Injection molding machine 51 ・ ・Drive device 52 Injection device 53 Mold clamping device 54 Fixing die plate 55 Moving die plate 56 Booster ram 57 Guide rod 60 Split mold 60a ... one mold 60b ... other mold 61 ... parting surface F1 A ... area B ... burr F ... mold clamping force M ... molding material Pc ... in the cavity Pressure S: Product projected area X: Boundary α: Surface pressure δ: Surface pressure

Claims (3)

[Claims] An injection molding machine having a mold clamping device (2) for clamping a molding die (15) having a molding cavity (19) and a control device (24) for controlling the mold clamping device (2). The control device (24) determines a leakage amount (Q) corresponding to an allowable burr formed by leakage of the molding material (M) from between the parting surfaces (18) of the molding die (15). The proportional equivalent gap distance (h) is calculated and calculated, and the gap equivalent distance (h) is calculated.
From the surface pressure (δ) and the input value of the surface roughness (Ra) of the parting surface (18), the surface pressure (δ) of the parting surface (18) is calculated. Calculating the overall pressure (δ × A) of the toning surface (18) and calculating the internal pressure (Pc × S) of the molding cavity (19) in the mold clamping direction from the holding pressure of the molding cavity (19); An injection molding machine for calculating and outputting a minimum mold clamping force (F) of the mold clamping device (2) by adding the total pressure (δ × A) and the internal pressure (Ps × S). . 2. An injection part (40) for injecting the molding material (M) from an injection nozzle, and a molding cavity (19) for molding the molding material (M) injected from the injection part (40). A mold (15) having a surface (18); and a pressure sensor (3) for detecting a holding pressure in the mold (15).
1) and the parting surface (1) of the mold (15).
8) A mold clamping device (2) for clamping the mold, and the mold clamping device (2).
A control device (24) for controlling the mold clamping force, wherein the control device (24) leaks an input value corresponding to an allowable burr of the molding material (M) between the parting surfaces (18). The gap equivalent distance (h) proportional to the quantity (Q) is calculated, and the gap equivalent distance (h) and the input surface (1) of the input value are calculated.
8) The surface pressure (δ) of the parting surface (18) calculated from the surface roughness (Ra) is obtained, and the entire surface pressure of the parting surface (18) obtained from the surface pressure (δ) is obtained. A minimum mold clamping force (F) is calculated from the internal pressure in the mold clamping direction of the molding cavity (19) calculated from the holding pressure (Pc) from the pressure sensor (31) and the minimum mold clamping force (F). An injection molding machine characterized in that the signal of (1) is input to the mold clamping device (2) to clamp the mold. 3. The surface pressure (δ) of the parting surface (18) for calculating the minimum clamping force (F) of the mold clamping device (2).
Is based on data previously measured for the correlation between the gap equivalent distance (h) of the mold (15), the parting surface roughness (Ra), and the surface pressure (δ) of the parting surface (18). The injection molding machine according to claim 1, wherein the calculation is performed.