摘要:
A method of and an apparatus for measuring and evaluating characteristics of material resin using an injection molding machine. Injections of resin are performed with different resin temperatures TCi and different injection velocities Vj to detect injection pressures Pr at set screw positions. Data of combinations (Pr, V, TC) of an N number of injection pressures, injection velocities and resin temperatures are obtained. An interdependency relation function PVT(t, v(x),x) expressing correlation among the injection pressure, the injection velocity and the resin temperature is obtained as PVT(t, v(x), x)=A(x)e−α(x)Tv(x)β(x) according to a least square method using the obtained data, where β(x) represents a degree of dependency on injection velocity influencing the injection pressure and “log A(x)−α(x)T” represents a degree of dependency on resin temperature influencing the injection pressure.
摘要:
A resin flow analysis in a die is performed by CAE or the like to obtain a resin pressure curve at a resin inlet port or a resin pressure curve at a nozzle end portion of a molding machine. Injection (air shot) is performed while a nozzle is separated from a die, so that an injection pressure curve Pa to be detected at this time is obtained. From the injection pressure curve and the resin pressure curve, an injection pressure command curve serving as a molding condition in mass production is obtained. The resin pressure curve obtained by the resin flow analysis is compensated by the injection pressure curve in an air shot for a time lag and pressure loss caused by the mechanical elements of an injection molding machine, so that molding conditions in mass production can be easily obtained. In addition, a pressure loss at the nozzle portion is also obtained, so that an injection pressure command curve is obtained from the pressure loss, the injection pressure curve, and the resin pressure curve.
摘要:
A metering controller capable of making a metering time constant and kneading of resin uniform. A screw torque STRQ(n) is detected and stored at every processing period from a start of metering as reference data. A screw rotational speed command is changed over to a set value at each predetermined changeover position. A present screw torque is detected and subtracted from a corresponding screw torque STRQ(n) of the reference data to obtain a deviation &Dgr;TRQ. A correction amount SROT for the screw rotational speed command is obtained based on the deviation &Dgr;TRQ. The correction amount SROT is added to the set screw rotational speed command SRCMD and thus corrected command is outputted for controlling a servomotor for rotating the screw. A screw retracting speed and a screw retracting position may be adopted as reference data. Since a transition pattern of the screw retracting motion coincides with that in obtaining the reference data, the metering time is made constant.
摘要:
An injection is carried out under a certain molding condition with a nozzle in an injection molding machine left open to sample an injection pressure Pr in every certain cycle for storing. Detected pressure data Pr(0) to Pr(N) for one shot is stored as reference pressure data Pr0(0) to Pr0(N). When defective molding occurs or when a resin lot is changed or the like, the injection is carried out with the nozzle left open under the same molding condition as that used in obtaining the reference pressure data to obtain the detected pressure data Pr(0) to Pr(N). Waveforms of the detected pressure data Pr(0) to Pr(N) and reference pressure data Pr0(0) to Pr0(N) are graphically represented so that variation of the molding condition is observed. It is assumed that if there are any differences, a problem resides in the resin, while if there is no difference but the defective molding occurs, the problem resides in a mold.
摘要:
A method of and an apparatus for precisely determining a separating force of a molded product from a mold by an ejector in an injection molding machine. A load exerted on an ejector mechanism in operation without a product molded in the mold is constituted by an inner resistance of the ejector mechanism. The inner resistance includes frictional force produced within the ejector mechanism and resilient forces of springs for returning ejector pins to retracted positions thereof. On the other hand, the load exerted on the ejector mechanism in operation with a product molded in the mold is constituted by the inner resistance and the separating force of the molded product from the mold. Thus, a difference between the loads detected in driving the ejector mechanism with and without a molded product at each ejector position precisely represents the separating force of the molded product from the mold. Judgment on defectiveness/non-defectiveness of the molded product, and abnormality of the injection molding operation and the ejector mechanism are performed more precisely based on the determined separating force of the molded product.
摘要:
A disturbance estimating observer is provided, which estimates a load applied to a servomotor for driving an ejector axis. When an ejector operates, the disturbance load torque estimated by the observer is sampled for each specific period (0 to j), and the data DA (0, 0) to DA (i, j) of (i+1) ejector processes are stored in a table TA in the form of cyclic storage. From this table TA, average values DB (0) to DB (j) of estimated disturbance load torques are determined in turn and they are stored in a table TB. From these average values, upper limit values DC (0) to DC (j) and lower limit values DD (0) to DD (j) of a permissible range are stored in tables TC, TD. When the determined estimated disturbance load torque has exceeded the permissible range, an abnormal load signal is outputted.
摘要:
Clamping and injection operations are executed partially in parallel by adjusting a clamping speed and an injection start timing T so that sum .SIGMA.P of resin pressure acting on the parting plane of a mold cavity will not exceed mold clamping force F outputted at that time. An injection operation is started during the period in which the mold clamping force F is relatively low between mold touch and mold clamping completion, so that gas breathing from the mold cavity can be done easily without providing gas vent in the mold, thereby preventing resin filling failure or burning. Also, the clamping and injection operations are executed partially in parallel, so that time required for clamping and injection processes is shortened by time T' as a whole. Therefore, speeding of molding cycle can be attained.
摘要:
A mold protection device for an injection molding machine capable of automatically setting a reference value for detecting an abnormal load exerted on a mold in a mold closing process. A load exerted on a servomotor for driving a mold clamping mechanism is estimated by a disturbance estimating observer provided in a control system of the servomotor. The estimated disturbance torque is sampled at every predetermined period in a mold protection region and cyclically stored in a table TA as data DA (0, 0) to (i, j) in mold closing processes of the number (i+1). A predetermined amount is added to an average value of data DA (0, n) to (i, n) to define an upper limit DC(n) for the disturbance torque and stored in the table TC. If the estimated disturbance torque at each sampling period exceeds the upper limit DC(n) of in the mold protection region in a present mold closing process, an alarm is issued to indicate abnormal load. An optimum reference value for determining an abnormal load is automatically set for securely protecting the mold without requiring an operator to manually set the reference value.
摘要:
An average is obtained between output readings of a pressure sensor obtained when forward and reverse thrusts are applied to an injection screw by positively driving a servomotor for injection. The average value is used as a correction value for a reading deviation of the pressure sensor. The injection servomotor is positively driven to apply a thrust to the screw. This known thrust and the actual reading of the sensor are compared. A deviation between these values is used as the correction value for the reading deviation of the sensor.
摘要:
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. Various reference values (x, p, t) and various upper and lower limit values (pu, pl, tu, tl, xu, xl) defining various permissible ranges for each of the screw positions and elapsed times that have been selected on the coordinate system are set in data display fields (8, 9), taking into account the distribution of the pressure curve groups and displayed contents shown in a data display field (10) and changing with movements of cursors (11, 12). During the execution of an actual molding cycle, each of the actual elapsed time period and actual injection pressure at each of selected screw positions, or each of the actual screw position and actual injection pressures at each of selected elapsed time periods is compared with its permissible range so as to check the acceptance/rejection of the same. Based on the resultant number of rejections, the conformity of a product is determined.