Abstract: A cylinder temperature controller for an injection molding machine in which an injection molding operation is performed while keeping the injection cylinder at a stable preset temperature regardless of disturbances such as the change of mold temperature or ambient temperature and the temperature rise caused by the shear compression of resin. A temperature regulator for carrying out PID feedback control of the injection cylinder temperature is provided with a PID adjusting means unit for automatic tuning. The actual temperature T of each portion of the injection cylinder is detected by a thermocouple. When the actual temperature T deviates from a predetermined temperature range defined by an upper limit [A+B] and lower limit [A-B] which are set on the basis of the preset target temperature A, an automatic tuning command is outputted to the temperature regulator. Upon receipt of this command, the PID adjusting unit sets the PID parameters again at a value suitable to the disturbance.

Abstract: An injection pressure monitoring method in which the correlations between a screw position, injection pressure, and cavity fill for an injection molding machine are monitored and displayed on a screen. The pressure for the position of a screw is graphically displayed on the screen, and a picture of a cavity is also displayed on the screen. By inputting the screw position, the pressure for the screw position is monitored, and at the same time, the resin filling state in the cavity corresponding to this screw position is displayed as an image.

Abstract: A monitoring method capable of properly collectively managing the operating states and operation records of a group of injection molding machines. Monitor data sets delivered from the individual injection molding machines are cyclically detected by means of a processor of a monitor unit, and a plurality of sets of up-to-date monitor data for the individual injection molding machines are renewably loaded into a plurality of data tables. When the preset time of a timer associated with any one of the injection molding machines is up, or when the current injection frequency reaches a predetermined frequency, it is concluded that the monitor data output timing is reached, and whether the monitor data should be printed or displayed on a screen is further determined.

Abstract: A method and an apparatus for monitoring injection pressure, using the relationship between positions of a screw (1), filling of resin in a cavity and injection pressure. Mold cavity data are stored, whereby a display screen (2) displays, based on said data, a configuration of the cavity and straight lines corresponding to cross sections along which the cavity is divided into a plurality of regions. Screw positions required to sequentially fill the divided regions of the cavity with the resin are obtained to be displayed on a coordinate axis representing a screw position in a pressure waveform graph (22). Then an operator changes the setting of molding conditions referring to the data on the display screen, and carries out the injection to obtain the pressure data corresponding to the screw position to be displayed on the pressure waveform graph (22).

Abstract: A product acceptance/rejection judgment method which always ensures accurate judgment whether a product is acceptable or not even when an injection molding machine is operated in different operating environments is implemented by a processor (22) of a numerically controlled device (20). When the processor determines that it should perform, in addition to a normal product acceptance/rejection judgment based on molding process parameters, an auxiliary product acceptance/rejection judgment based on at least one operating parameter which directly indicates an injection molding machine operating environment characteristic involved in the acceptance/rejection judgment of the product, the processor reads output data from an A-D converter (11, 12 or 13) which data corresponds to the actual value of at least one operating parameter detected by an appropriate die temperature sensor (8), open air temperature sensor (9) or a wind velocity sensor (10).

Abstract: An article conformity discriminating apparatus for an injection molding machine is capable of automatically discriminating the conformity of articles with accuracy without using a conforming article sample. In molding cycles for mass production of articles executed according to optimum molding conditions of a mold file read from a shared memory (105), an actual resin pressure detected by a pressure sensor (4) is periodically sampled according to an output of an address generator (118), while a reference resin pressure sampled in the same sampling period or a corresponding sampling period on a pressure transition pattern, in a conforming article molding process for determining the optimum molding conditions made before the mass production of the articles, is read from the shared memory, (105) by a processor (114), and the actual resin pressure is compared with the reference resin pressure.

Abstract: An injection compression molding method and an apparatus therefor are provided, which are capable of accurately performing a molten resin compression operation during execution of an injection/hold operation or a metering operation, so as to produce high-quality molded products with no substantial variations between these products.

Abstract: A discrimination method for maintenance timing for injection molding machines, detects the respective values of molding process parameters of a plurality of types, including injection time, maximum injection pressure, etc., for each of the injection molding machines (7-1 to 7-M). Up-to-date process parameter values for the molding machine are entered as a set of monitor data in a molding monitor unit (1) every time a predetermined number of molding cycles are executed in each molding machine. A plurality of monitor data values for each type are read, on a time-series basis, from a memory (4) loaded with a plurality of sets of up-to-date monitor data values associated with each molding machine, by means of a microprocessor (2), and dot-line data are generated.

Abstract: A method of monitoring a resin position intended to automatically display the relationship between the state of resin injected into the cavity and the screw position for monitoring. In the cavity, border sections where flow resistance of the injected changes are determined. Subsequently, a volume is found for each of the regions partitioned by the border, and the obtained volume is set into the control unit of the injection molding machine. The control unit displays the injection completion position when the amount of cushion Lc is inputted (200, 201). Moreover, the amount of a screw stroke Sj is determined on the basis of the volume determined for each of the positions having different flow resistance, and a screw diameter. Each amount of the screw stroke Sj is added to the amount of cushion Lc in sequence to find screw positions, which are to be displayed as injection speed changeover positions (203).

Abstract: A product acceptance/rejection judgment method in an injection molding machine, which makes it possible to properly and quickly set judgment standard parameters and accurately judge whether a product is acceptable or not. Based on injection pressures and screw positions periodically sampled during each of a plurality of injection processes in nondefective product molding, an injection pressure curve group represented as a function of the screw position and an injection pressure curve group represented as a function of the time period elapsed from the start of injection are displayed on two coordinate systems (6, 7) on a display screen.

Abstract: An injection/hold pressure control apparatus which permits the production of high-quality molded articles without the need of using an expensive internal mold pressure sensor. When a plurality of points specifying a target injection/hold pressure curve represented as a function of the time period elapsed after the start of injection are manually input in succession, a processor (109) of a numerical control unit (100) calculates a group of target injection/hold pressure data on the basis of the target pressure curve drawn on a screen of a display unit (113), and stores them in a lookup table in a shared memory (102). Upon start of the injection, a comparator (11), connected to a pressure sensor (4) mounted on an injection screw (1) for detecting an actual injection/hold pressure, is connected to the numerical control unit through a first changeover switch (6).

Abstract: A molding condition recording apparatus having a manual data input device with a CRT. The manual data input device has various keys for inputting parameters of various groups used for controlling injection, hold, metering and cylinder temperature, and for inputting molding defect indication data. A microprocessor for a programmable machine controller causes the input parameters and the molding defect indication data to be stored in a molding condition storage region of a shared memory (S5). The microprocessor then discriminates similarity between the thus stored molding condition and the molding condition already registered in a molding condition/molding defect storage file of a memory other than the shared memory (S7). If there is similarity between these molding conditions, the microprocessor causes the CRT to display an alarm message thereon together with the parameter already registered in the file and the mold defect indication data (S12).

Abstract: An injection control method for an electrically-operated injection molding machine is provided, which is capable of sharply increasing the injection speed of a low-priced electric injection molding machine. A command pulse train is supplied to a servo circuit for an injection servomotor whereby substantial rotary motion of the injection servomotor is initially prevented, as a result of the fact that the torque limit value (Ts) is set at a value sufficient to establish equilibrium between the output torque of the injection servomotor and the resin pressure acting on the injection screw. The error between the target rotational position of the injection servomotor and an actual rotational position thereof then is allowed to increase until it reaches a feed stop positional error (Fs).

Abstract: A method and an apparatus for pressure control of a motor-operated injection-molding machine, which are capable of effecting various modes of multi-stage pressure control smoothly without mounting a special servomotor on the injection-molding machine or replacing servomotor with another servomotor. When a shift is made from an injection process into a first pressure hole stage of a pressure hold process, or from each pressure hold stage to a pressure hold stage subsequent thereto, a central processing unit for numerical control calculates a modification amount. This modification amount is obtained by dividing a value, obtained by subtracting a maximum injection pressure or a torque limit value for a preceding pressure hold stage from a torque limit value for a subsequent pressure hold stage, by a required modification frequency. The modification frequency is obtained by dividing a predetermined switching time for the subsequent pressure hold stage by a hold pressure control operation execution period (S7).

Abstract: A method for positioning an operating unit of an electrically-operated injection molding machine at a predetermined operating position in an optimum manner, by using widths of positive-side and negative-side regions of an allowable positioning zone which are set independently of one another in accordance with the operating direction of the operating unit and the function to be achieved by the operating unit. Positioning of a screw at an injection-end position is completed when the actual screw position (PA) is equal to or less than the sum of a target injection-end position (PS) and the positive-side region width (W1), which is set to "0", and is equal to or larger than the value obtained by substracting the negative-side region width (W2) from the target position (PS), so that the screw is positioned at the target injection-end position or a screw-moving position which slightly exceeds the target position by a permissible distance, to thereby actually control an amount of shot.

Abstract: A software servo control apparatus for use in an electrically-operated injection molding machine, which is capable of changing servo control variable constants, without the need of changing hardware arrangement, for greatly enhancing versatility for the machine, and of effecting appropriate pressure control. A servo control microprocessor (13) operates, in accordance with a servo control program, to determine a commanded current on the basis of a positional deviation amount, obtained from an output of a pulse encoder (5), and a moving command. The servo control microprocessor also determines an amount of a change in the output of the pulse encoder, and supplies a power amplifier (6) with the difference between the commanded current and an output of the same amplifier, for control of the drive of a servomotor (2). Further, the output of the amplifier is restricted to a value less than a commanded torque on the basis of an output of a pressure sensor (4) and the commanded torque.

Abstract: A method for controlling an injection motor of an injection-molding machine to prevent overheating such that injection-molding conditions to prevent the injection motor from overheating can be set securely. When injection-molding conditions are initially set (S1-S3), the ratio (R) between the integral of the amount of heat, produced by an injection motor driving current for one injection-molding cycle, and the allowable integral of the heat amount obtained when a continuous rated current flow is calculated (S5) before the one injection-molding cycle is executed in accordance with the new set injection-molding conditions. Then, the calculated ratio (R) and an allowable ratio (Rmax) are compared, and it is previously determined (S6) whether an overheating state of the injection motor can be produced when the injection-molding cycle is executed in accordance with the set conditions. If overheating can be produced, a warning is issued (S7).

Abstract: There is provided a die-touch position detecting apparatus capable of automatically and accurately detecting a die-touch position of a direct mold clamping mechanism driven by means of a servomotor. A numerical control unit (10) performs pulse distribution to a servo-circuit (30) in response to a die-touch position detecting operation command inputted through a manual data input device (17), thereby moving a movable platen toward a stationary platen. When the amount of errors accumulated in an error register (31) of the servo-circuit exceeds a predetermined value, the numerical control device stops the pulse distribution to the servo-circuit, and then calculates the die-touch position in response to the amount of pulse distribution to the servo-circuit and the amount of errors.

Abstract: A metering method for an injection molding machine, which drives a screw with a servo motor in the axial direction to perform injection including the step of applying a back pressure during metering. In order to perform high-precision metering, the servo motor is driven even after the screw position has reached a metering point, so that the screw is held at the position of the metering point.

Abstract: A control method for an injection motor is capable of preventing the injection motor from overheating. Injection motor current values are sampled at intervals having a predetermined sampling cycle. The value for each interval is squared and the squares are summed up over an injection molding cycle time and multiplied by the predetermined sampling time cycle. A ratio of an amount of heat produced when a continuous rated current flows and that produced when a maximum current flows is also determined. The injection molding cycle time is then subtracted from a value obtained by dividing the above-mentioned multiplied sum by the product of the above-mentioned ratio and the square of the maximum current. A determination is made as to whether the sign of the resultant value is positive or negative. When the sign is positive the motor is in its overheating state, and a quiescent time is provided to lengthen the injection molding cycle time (steps S8-S11).