JP2649009B2 - Method and apparatus for setting weighing value of injection molding machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for setting a measured value of an injection molding machine suitable for setting a measured value of an injection molding machine using a mold whose mold data is unknown.

[0002]

2. Description of the Related Art Generally, there are cases where mold data is known or unknown for molds used in an injection molding machine. For example, when manufacturing a product, if all manufacturing processes including mold design are provided in-house, mold data such as cavity capacity can be known from a mold drawing or a model. However, in a manufacturing company or the like having only a manufacturing section, there are cases where only a mold is given when a molding commission is received. In this case, the mold data is often unknown.

By the way, when setting a weighing value (a weighing stroke) as a molding condition, if mold data such as a cavity volume is known, a certain temporary weighing value is set as an initial condition and molding is performed. Although it can be performed, it is not easy to set the weighing value when the mold data is unknown. For this reason, conventionally, a skilled operator visually inspects the mold cavity and the like, sets initial conditions such as injection speed and injection pressure based on intuition and experience, and sets a small measurement value at first to perform molding. Then, while gradually increasing the measured value while observing the filling state of the molded article, the molding is repeated to set the measured value by trial and error.

[0004]

However, the above-mentioned conventional method has the following problems since it has to rely on the intuition and experience of a skilled operator.

[0005] First, since the operator who performs the setting operation requires considerable skill, the operators who can make the setting are limited. In addition, since the setting operation cannot be easily performed even by a skilled operator, the setting time is prolonged, the productivity is reduced, and the manufacturing cost is increased. In addition, useless resources and energy are consumed.

Second, if the weighing value is excessively set due to a setting error or improper setting, abnormal pressure may be applied to the inside of the mold, and the mold may be damaged. Also inferior.

The present invention has been made to solve the problem existing in the prior art, and enables an operator with low skill to easily and easily measure values when using a mold whose mold data is unknown. A method and apparatus for setting a weighing value of an injection molding machine, which can be set securely, and which can significantly reduce setting time, improve productivity, reduce manufacturing costs, save resources and energy, prevent mold damage, and improve safety. The purpose is to provide.

[0008]

A weighing value setting method according to the present invention provides an initial condition for setting a weighing value Md of an injection molding machine 1 using a mold 2 whose mold data is unknown.
The injection speed is set to the first speed value Vh on the high speed side, the injection start position of the screw is set to the retreat position Xb, and the injection pressure is set to the single pressure value P for the low pressure side.
d, and the screw 3 is advanced under the set initial conditions to inject and fill the mold 2 with the resin L, and the injection speed V is monitored so that the injection speed V is equal to or less than the preset set speed Vs. After that, set in advance
When the set time Ts has elapsed, the injection end position Xf of the screw 3 is detected, and the injection stroke Si is obtained from the detected injection end position Xf and the last retreat position Xb, and the weighing value Md is calculated based on the injection stroke Si. It is characterized by setting.

In this case, a reforming cycle in which the magnitude of the injection pressure is changed by a predetermined amount in accordance with the degree of defective filling of the formed molded article , and reforming is performed with the changed injection pressure, It is desirable to repeat the process until a non-defective product is formed, and to detect an injection end position Xf when a non-defective product is formed. On the other hand, the measured value Md is equal to the injection stroke S.
It can be set by adding a preset cushion stroke Sc to i.

When detecting the injection end position Xf, the injection pressure P during injection filling is monitored, and the injection end position Xf is detected when the injection pressure P exceeds a preset pressure Ps. Is also good. Again,
The above-described method, that is, the same as the case of monitoring the injection speed V and detecting the injection end position Xf when the injection speed V becomes equal to or lower than the set speed Vs, can be performed.

On the other hand, the measurement value setting device M of the injection molding machine according to the present invention sets the injection speed to the first speed value Vh on the high speed side and sets the screw injection start position to the last retreat position Xb as initial conditions.
Initial condition setting means A for setting the injection pressure to one pressure value Pd on the low pressure side, injection speed detecting means B for detecting the injection velocity V, and screw position detecting means C for detecting the screw position are set. The injection speed V when the screw 3 is moved forward according to the initial conditions and the resin L is injected and filled into the mold 2 whose mold data is unknown becomes equal to or lower than the preset set speed Vs , and then set in advance. Set time Ts
When the injection end position Xf of the screw 3 is detected, the injection stroke Si is obtained from the injection end position Xf and the last retreat position Xb, and the control means D for setting the weighing value Md based on the injection stroke Si is determined. It is characterized by having.

In this case, it is desirable that the control means D has a function of setting the measured value Md by adding a preset cushion stroke Sc to the injection stroke Si.
Furthermore, it is desirable that the control means D be provided with an injection pressure changing means E for changing the magnitude of the injection pressure by a preset change amount in accordance with the degree of defective filling of the molded article.

The control means D controls the injection end position X
In detecting f, the injection end position Xf when the injection pressure P becomes equal to or higher than a preset pressure Ps may be detected by monitoring the injection pressure P during injection filling. In this case as well, the injection speed V can be monitored, and when the injection speed V falls below the set speed Vs, the injection end position Xf can be detected in the same manner. Therefore, in this case, an injection pressure detecting means F for detecting the injection pressure P is provided.

[0014]

According to the measuring value setting method and apparatus M of the present invention, when the mold 2 whose mold data is unknown is loaded into the injection molding machine 1, the injection speed is increased by the initial condition setting means A. , The injection start position of the screw is set to the last retreat position Xb, and the injection pressure is set to the low pressure side one pressure value Pd as initial conditions.

Next, the screw 3 is advanced under these initial conditions, and the mold 2 is injected and filled with the resin L. This allows
Obtain moldings based on initial conditions. By the way, since the injection pressure is initially set as the one pressure value Pd on the low pressure side, when the molded article is poorly filled, the injection pressure changing means E changes the injection pressure (one pressure value Pd). In this case, in response to the degree of defective filling of the molded product, the injection pressure is changed by a preset change amount, and a remolding cycle of performing remolding with the changed injection pressure is performed until a good product is molded. repeat.

Since the injection speed V at the time of injection filling is detected by the injection speed detecting means B, the control means D monitors the injection speed V and detects the injection end position Xf of the screw 3 when a good product is formed. In this case, if the mold L is being filled with the resin L, the injection speed V is equal to the set speed Vs.
However, when the filling of the resin L is completed, the injection speed V rapidly decreases. Accordingly, when the injection speed V becomes equal to or lower than the preset speed Vs, if the screw position detecting means C detects the position of the screw 3, this position becomes the injection end position Xf.

Therefore, after the injection speed V falls below the set speed Vs by the control means D, the preset time T
By taking in the injection end position Xf of the screw 3 when s has elapsed, the injection stroke Si (= Xb−Xf) can be calculated from the injection end position Xf and the last retreat position Xb. The reason for setting the set time Ts is to detect the injection end position Xf more accurately. Then, by adding a preset cushion stroke Sc to the injection stroke Si, the measured value Md can be obtained, and the obtained measured value Md is set as a molding condition.

On the other hand, when the mold 2 is being filled with the resin L, the injection pressure P is smaller than the set pressure Ps.
Is completed, the injection pressure P sharply increases.
Therefore, when the injection pressure P obtained from the injection pressure detecting means F becomes equal to or higher than the preset pressure Ps, the screw 3
Is detected, this position becomes the injection end position Xf, and the measured value Md can be obtained in the same manner as described above.

[0019]

Next, preferred embodiments according to the present invention will be described in detail with reference to the drawings.

First, a schematic configuration of the injection molding machine 1 provided with the measurement value setting device M according to the present invention will be described with reference to FIG.

The injection molding machine 1 has a machine base 4.
Is provided with an injection device 5 on one side of the upper surface, and a mold 2 with unknown mold data covered with a safety cover 6 on the other side of the upper surface.
Is provided. In this case, the mold 2 is supported by a mold clamping device not shown in the figure, and the injection device 5 is
To move forward and backward. The injection device 5 has an injection nozzle 9 at the tip.
Is provided with a heating cylinder 8 having a hopper 10 at the rear, and the screw 3 is built in the heating cylinder 8 (see FIG. 2). On the other hand, a screw driving device 11 for rotating and moving the screw 3 forward and backward is provided at the rear end of the heating cylinder 8. As the screw driving device 11, an electric driving type using a servomotor and a hydraulic driving type using a hydraulic circuit are known.

On the other hand, in FIG. 8, M is a weighing value setting device. In the weighing value setting device M, reference numeral 12 denotes a controller built in the machine base 4 and controlling the entire injection molding machine 1. Reference numeral 13 denotes an input device (keyboard) attached to the side panel 4p of the machine base 4, and is connected to the controller 12. The input device 13 and the controller 12 have a setting function for setting various conditions, and particularly constitute an initial condition setting means A and an injection pressure changing means E for changing the magnitude of the injection pressure in the present invention. Furthermore, 14
Is a screw position detector constituting the screw position detecting means C. For example, in the case of an electric drive type, a rotary encoder for detecting the number of revolutions of a servomotor, and in the case of a hydraulic drive type, a linear encoder for directly detecting the screw position. A scale etc. can be used. The screw position detector 14 is directly connected to the controller 12, and is also connected to the controller 12 via the speed converter 15. The speed converter 15 constitutes the injection speed detecting means B, and has a function of differentiating the position signal from the screw position detector 14 and converting it into a screw speed signal. The controller 12 obtains an injection stroke Si from various setting information set by the input device 13, position information of the screw 3 obtained from the screw position detector 14, and speed information of the screw 3 obtained from the speed converter 15,
Control means D for setting the weighing value Md based on the injection stroke Si is configured.

On the other hand, reference numeral 16 denotes an injection pressure detector which constitutes the injection pressure detecting means F. For example, in the case of an electric drive type, a load cell for detecting the back pressure at the rear end of the screw 3 and in the case of a hydraulic drive type, Can use a hydraulic pressure sensor for detecting the hydraulic pressure of the hydraulic cylinder. Reference numeral 17 denotes a display attached to the side panel 4p, which performs various displays,
It is used as an auxiliary device of the input device 13. Also,
The controller 12 is connected to the system computer 18 by an optical communication system (wireless system) or the like.

Next, a weighing value setting method according to the present invention including the function of the weighing value setting device M will be described with reference to FIGS.

FIG. 3 is an overall flowchart showing the procedure for setting a weighing value. First, using the input device 13 and the display 17, known data relating to a molding material, a specification screw, and the like is input. The controller 12 stores a database relating to material characteristics, molding machine performance specifications, basic molding conditions, and the like. The controller 12 uses the input known data and the stored database to store temperature-related molding conditions, such as screw maximum stroke, etc. Is determined in the controller 12. The molding conditions relating to the temperature, that is, the heating cylinder temperature and the mold temperature are automatically set based on the type of the molding material.

On the other hand, the selection key Ks on the input device 13
By pressing, the weighing value setting mode is selected and initial conditions are set (steps 21 and 22). The setting of the initial condition is performed according to the flowchart shown in FIG.

First, as an injection condition, the injection speed is set to the first speed value Vh on the high speed side (step 41). in this case,
The first speed value Vh on the high speed side is higher than the middle point of the set range in the injection molding machine to be used, and preferably a value of 90% or more with respect to the maximum speed is selected. Further, the injection start position of the screw 3 is set to the last retreat position Xb (step 42). In this case, the last retreat position Xb does not mean a complete rear end, but is a concept including an arbitrary rear position at which a sufficient amount of resin can be measured with respect to the volume of the mold 2. Furthermore, the injection pressure is set to the one pressure value Pd on the low pressure side (step 43). In this case, the one pressure value Pd on the low pressure side is lower than the middle point of the set range in the injection molding machine to be used, and is desirably set to a value of 30% or less with respect to the maximum pressure. In addition to the above settings, in the setting of the initial conditions, various molding conditions such as a pressure-holding switching position, a back pressure, a cooling time, and a screw rotation speed are set (step 44).

Further, according to the present invention, a set speed Vs and a set time Ts for detecting the injection end position Xf of the screw 3 are set. The set speed Vs is a threshold value for the injection speed V for detecting the completion of the filling of the mold 2 with the resin, and can be set to several m / sec which is almost in a stopped state. The set time Ts is a time for ensuring more reliable filling after the speed becomes equal to or less than the set speed Vs, and can be set to, for example, about several seconds.

Next, the back pressure is turned off (zero), and measurement is performed without back pressure (step 23). At this time, screw 3 is
As shown in (a), it retreats to the last retreat position Xb. Then, by selecting the semi-automatic molding mode, the injection device 5 (the injection nozzle 9) advances (steps 24, 2).
5). On the other hand, the injection is started by the nozzle touch. That is, the screw 3 moves forward according to the set initial conditions, and the mold 2 is injected and filled with the resin L (step 26). At this time, the controller 12 monitors the injection speed V at the time of filling obtained from the speed converter 15. As shown in FIG. 1, if the injection speed V is in the middle of filling the resin L into the mold 2, the set speed V
s is much larger than s, and when the filling of the resin L is completed, it rapidly decreases and becomes equal to or lower than the set speed Vs. Therefore, the injection speed V is monitored, and when the injection speed V becomes equal to or lower than the set speed Vs, the set time Ts is counted (step 2).
7, 28). When the set time Ts has elapsed, the injection end position Xf shown in FIG. 2B is monitored (steps 29 and 30).

Next, the injection pressure is changed (step 31). This change processing mainly increases the injection pressure (one pressure value Pd) set on the low pressure side to an appropriate value, and FIG. 5 shows a flow chart of the change processing procedure.

At this time, first, the back pressure is turned on, measurement is performed with the back pressure applied, the injection device 5 (injection nozzle 9) is retracted, and the mold 2 is opened (step 5).
1, 52, 53). Then, while judging a defective filling of the taken-out molded article, a necessary data collection, for example, a data collection of a wall thickness, a gate pressure and the like is performed (Step 5).
4). At this time, the cooling time is automatically calculated from the collected data on the thickness and the gate pressure.

By the way, the input device 13 is provided with selection keys K1, K2, K3 (see FIG. 8) for selecting the type of the filling defect and the rank for each filling defect, and the controller 12 eliminates the filling defect. A plurality of change amounts corresponding to each rank for changing the injection pressure P in the direction in which the injection pressure P is changed are set.

For example, in the case of a short shot, as shown in FIG.
It is classified into three levels of “medium” and “small”. When “large”, the pressure change rate (change amount) is “+ 20%”, and when “medium”, the pressure change rate is “+ 10%”, “ When "small", the pressure change rate is set to "+ 5%". In this case, the ranks are set to “large”, “medium”, and “small”, but of course, they may be converted into numerical values. The pressure change rate is used as the change amount because the injection pressure is usually set as a ratio to the maximum pressure. Therefore, for example, if “large” is selected as the degree of the short shot, the pressure change rate “+”
"20%" is selected, and 20% is added to the set injection pressure ratio. As described above, the change amount may be set as an absolute amount or a ratio, or may be changed by adding or subtracting or multiplying or dividing the injection pressure.

Similarly, in the case of overfilling, as shown in FIG. 7, the degree of overfilling is classified into three levels of "small", "medium", and "large". When the pressure change rate is “−2%”, when “medium”, the pressure change rate is “−5%”,
When "large", the pressure change rate is set to "-10%". As described above, in any case, the pressure change rate is set so as to increase in accordance with the rank in which the degree of defective filling is large.

Therefore, the molded product is visually inspected, and if a short shot has occurred due to insufficient filling, processing for increasing the injection pressure is performed (steps 55 and 56). That is,
The degree of the short shot is determined. For example, if the degree is “large”, the corresponding selection key K1 on the input device 13 may be pressed. In this case, since the injection pressure is set to the one pressure value Pd on the low pressure side as an initial condition, if the one pressure value Pd is set to 20%, the controller 12 sets the pressure change rate to the injection pressure 20%. The injection pressure is changed to 40% by adding 20%. Then, reshaping is performed with the changed (increased) injection pressure, that is, steps 25 to 31 shown in FIG. 3 and steps 51 to 5 shown in FIG.
The remolding cycle, which is the process of step 4, is executed (step 5).
7). Then, if a short shot has further occurred in the molded product, a process of increasing the injection pressure is performed again. That is, if the degree of the short shot is “medium”, similarly, 10% of the pressure change rate is added to the injection pressure, and the reshaping cycle is executed. Since the magnitude of each pressure change rate is different and is set to be large corresponding to the rank with a high degree of defective filling, if the remolding cycle after changing the injection pressure is repeated, the rank to be selected is selected. Gradually becomes smaller, and finally a good product can be obtained (step 5).
8).

On the other hand, when the molded article is visually inspected and a defective filling such as a burr due to overfilling occurs, a process for reducing the injection pressure is performed (steps 59 and 60). In this case, the degree of overfill is determined and, for example, the degree is “small”.
Then, by pressing the selection key on the input device 13, the controller 12 subtracts 2% of the pressure change rate from the set injection pressure magnitude. Then, reshaping by the changed (reduced) injection pressure, that is, the reshaping cycle is repeated until a good product is obtained (steps 61 and 6).
2).

Therefore, if a non-defective product is finally obtained, the controller 12 captures the current injection end position Xf obtained from the screw position detector 14, and calculates the injection stroke from the obtained injection end position Xf and last retreat position Xb. Si (= X
b-Xf) is calculated, and the cushion value Sc set in advance is added to obtain the weighing value Md. Then, the measured value Md is used as a molding condition by the controller 12.
(Step 32).

In the embodiment described above, the injection end position X
In detecting the injection speed f, the injection speed V is monitored.
Although the injection end position Xf is detected when is equal to or lower than the set speed Vs, the injection pressure P obtained from the injection pressure detector 16 may be monitored by setting the set pressure Ps as a threshold value. That is, the injection pressure P is much smaller than the set pressure Ps while the mold 2 is being filled with the resin L, and rises rapidly after the filling of the resin L is completed to reach the set pressure Ps or more. Become. Therefore, based on the fact that the injection pressure P has reached the set pressure Ps, the injection end position Xf can be detected in the same manner as in the above-described embodiment.

The embodiment has been described in detail above.
The present invention is not limited to such an embodiment.
For example, the injection stroke Si may be set as the measurement value Md, and the necessary processing may be performed at the time of measurement. In addition, it is possible to arbitrarily change the detailed configuration, method, and the like without departing from the gist of the present invention.

[0040]

As described above, according to the method for setting a measured value of an injection molding machine according to the present invention, when setting a measured value of an injection molding machine using a mold whose mold data is unknown, an injection condition is set as an initial condition. Set the speed to the first speed value on the high speed side, set the screw injection start position to the last retreat position, set the injection pressure to the one pressure value on the low pressure side, and advance the screw according to the set initial conditions. The injection speed (or injection pressure) is monitored by monitoring the injection speed (or injection pressure) so that the injection speed (or injection pressure) is equal to or lower than a preset speed (or higher).
After that, when a preset time has elapsed , the injection end position of the screw is detected, and the injection stroke is obtained from the detected injection end position and the last retreat position. Since the weighing value is set based on this, the following remarkable effects are obtained.

Even a low-skilled operator can easily and reliably set a weighing value when using a mold whose mold data is unknown, greatly reducing the setting time, improving productivity, reducing manufacturing costs, and reducing resources. And energy can be saved.

Since setting errors and improper settings are eliminated, it is possible to prevent damage to the mold and improve safety.

Further, the measuring value setting device of the injection molding machine according to the present invention, as the initial conditions, sets the injection speed to the first speed value on the high speed side, the injection start position of the screw to the rearmost position, and the injection pressure to the low pressure side. An initial condition setting means for setting each pressure value, an injection speed detecting means for detecting an injection speed (an injection pressure detecting means for detecting an injection pressure), a screw position detecting means for detecting a screw position, Injection speed (injection pressure) when the screw is advanced according to the conditions and resin is injected and filled into a mold whose mold data is unknown.
When the preset speed is equal to or less than the preset speed (not less than the preset pressure) , the preset end time of the screw is detected and the injection end position of the screw is detected. Since the control means for determining the stroke and setting the weighing value based on the injection stroke is provided, a remarkable effect that the weighing value setting method according to the present invention can be easily and reliably implemented.

[Brief description of the drawings]

FIG. 1 is a characteristic diagram including an injection speed for explaining a measurement value setting method according to the present invention;

FIG. 2 is a schematic cross-sectional view of a heating cylinder showing a screw position when the measurement value setting method is performed.

FIG. 3 is a flowchart showing a procedure of the weighing value setting method;

FIG. 4 is a flowchart showing a procedure for setting initial conditions in the weighing value setting method;

FIG. 5 is a flowchart showing a procedure for changing an injection pressure in the same measurement value setting method;

FIG. 6 is a principle explanatory diagram for explaining a method of changing the injection pressure in the same weighing value setting method;

FIG. 7 is another principle explanatory diagram for explaining a method of changing the injection pressure in the same measurement value setting method.

FIG. 8 is a schematic configuration diagram of an injection molding machine including a measurement value setting device according to the present invention;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Injection molding machine 2 Die 3 Screw M Measuring value setting device A Initial condition setting means B Injection speed detecting means C Screw position detecting means D Control means E Injection pressure changing means F Injection pressure detecting means L Resin Vh Higher injection speed First speed value Pd One pressure value on the low pressure side of the injection pressure Xb Screw retreat position Xf Screw injection end position Si Injection stroke

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Fumihiro Kobayashi 2110, Nanjo, Nanjo, Hanjo-gun, Nagano Prefecture Nissei Jushi Kogyo Co., Ltd. Incorporated company (56) References JP 4-76767 (JP, B2)

Claims (14)

(57) [Claims] When setting a weighing value of an injection molding machine using a mold whose mold data is unknown, as an initial condition, the injection speed is set to a high speed side, and the injection start position of the screw is moved backward. At the position, the injection pressure is set to one pressure value on the low pressure side, and the screw is advanced under the set initial conditions to inject and fill the mold with the resin, and the injection speed is monitored in advance by monitoring the injection speed. After the speed becomes equal to or less than the set speed , when a preset time has elapsed, an injection end position of the screw is detected, and an injection stroke is calculated from the detected injection end position and the last retreat position. And setting a weighing value based on the injection stroke. 2. A reforming cycle in which the magnitude of the injection pressure is changed by a preset change amount in accordance with the degree of defective filling of the molded article, and the remolding cycle for reforming with the changed injection pressure is performed by a non-defective product. 2. The method for setting a weighing value of an injection molding machine according to claim 1, wherein the injection end position when a non-defective product is molded is detected until the molding is completed. 3. The method for setting a weighing value of an injection molding machine according to claim 1, wherein the weighing value is set by adding a preset cushion stroke to the injection stroke. 4. When setting a weighing value of an injection molding machine using a mold whose mold data is unknown, as an initial condition, the injection speed is set to a high speed side, and the injection start position of the screw is moved backward. At the position, the injection pressure is set to one pressure value on the low pressure side, and the screw is advanced according to the set initial conditions to inject and fill the mold with the resin, and the injection pressure is monitored in advance by monitoring the injection pressure. When the pressure becomes equal to or higher than the set pressure, the injection end position of the screw is detected, an injection stroke is obtained from the detected injection end position and the last retreat position, and a weighing value is set based on the injection stroke. How to set the weighing value of the injection molding machine. 5. The weighing value setting of an injection molding machine according to claim 4 , wherein an injection end position is detected when a preset time elapses after the injection pressure becomes equal to or higher than the set pressure. Method. 6. A re-forming cycle in which the magnitude of the injection pressure is changed by a preset change amount in accordance with the degree of defective filling of the molded article and re-molding is performed with the changed injection pressure. 6. The method according to claim 4 , wherein the step of detecting the end of injection when a non-defective product is molded is detected until molding is completed. 7. A metric weighing value setting method for an injection molding machine according to claim 4, 5 or 6, wherein setting by adding a cushion stroke preset the injection stroke. 8. Initial condition setting means for setting an injection speed to a first speed value on a high speed side, an injection start position to a last retreat position, and an injection pressure to a single pressure value on a low pressure side as initial conditions. Injection speed detection means for detecting the injection speed, screw position detection means for detecting the screw position, and when the screw is advanced under the set initial conditions and the resin is injected and filled into the mold whose mold data is unknown. after the injection speed, equal to or less than set speed previously set in advance set
A control means for detecting an injection end position of the screw when a predetermined set time has elapsed, obtaining an injection stroke from the detected injection end position and the last retreat position, and setting a weighing value based on the injection stroke. A weighing value setting device for an injection molding machine. 9. The control means in response to the degree of filling defects of the molded article obtained by molding, according to claim, characterized in that it comprises an injection pressure changing means for changing only the changes amount set the size in advance of the injection pressure 8 A weighing value setting device for an injection molding machine as described in the above. 10. The measurement value setting device for an injection molding machine according to claim 8, wherein the control means sets the measurement value by adding a preset cushion stroke to the injection stroke. 11. Initial condition setting means for setting an injection speed to a first speed value on a high speed side, an injection start position to a last retreat position, and an injection pressure to a single pressure value on a low pressure side as initial conditions. Injection pressure detecting means for detecting the injection pressure, screw position detecting means for detecting the screw position, when the screw is advanced according to the set initial conditions, and when the resin is injected and filled into a mold whose mold data is unknown. When the injection pressure in the above becomes equal to or higher than a preset pressure, the injection end position of the screw is detected, and the injection stroke is obtained from the detected injection end position and the last retreat position, and a weighing value is set based on the injection stroke. A weighing value setting device for an injection molding machine, comprising: 12. The injection molding machine according to claim 11, wherein the control means detects the injection end position when a predetermined time has elapsed after the injection pressure has become equal to or higher than the set pressure. Weighing value setting device. 13. The control device according to claim 11, further comprising an injection pressure changing means for changing the magnitude of the injection pressure by a predetermined amount in accordance with the degree of defective filling of the molded article. Or a weighing value setting device for an injection molding machine according to claim 12 . 14. A measuring value setting apparatus for an injection molding machine according to claim 11, wherein the control means sets the measuring value by adding a preset cushion stroke to the injection stroke.