Abstract: An injection molding machine is provided which uses servo motors (M1, M2) as driving sources and in which a preset back pressure is correctly transmitted to a resin. The torque limit values and rotating directions of an injection servo motor in respective stages is set in accordance with the relationship in magnitude between the preset back pressure and the resistance during a transmission mechanism of the respective stages of metering. A servo circuit of an injection servo motor is torque-limited with a preset torque limit value, and the injection servo motor is driven in a preset rotating direction.

Abstract: An injection molding machine wherein the values of variables for the current and several preceding molding cycles are displayed simultaneously, so as to perform process monitoring. Detection values of the variables in the current molding cycle are stored in a current value memory section of a memory (14). Every time a molding cycle ends, a CPU (11) transfers data from the current value memory section and past variable memory sections (which store the detection values of the respective variables of several preceding steps), to the past variable memory sections for the next preceding cycles. As a result the stored data of the memory sections is sequentially updated. The updated data and the current data are read out and displayed on a display unit (18).

Abstract: Disclosed is an injection-molding machine in which the injection acceleration/deceleration time can be varied in accordance with parameters related to injectin, such as the properties of resin, etc., thus permitting injection-speed control under optimum conditions.Pulse distribution is preformed with a predetermined cycle in accordance with a set injection speed (V1.about.V3) for an injection-speed control step corresponding to a detected screw position. A certain number (Pb) of pulses are delievered as an output, the number being obtained by dividing, by a predetermined value (n), the result of addition of the number (Pa) of distributed pulses for the current cycle and the number (X1.about.Xn1-) of distributed pulses for a period equivalent to a predetermined number of cycles preceding the current cycle. Thus, the acceleration/deceleration processing is accomplished, and an injecting operation is performed with an optimum acceleration/deceleration characteristic.

Abstract: An operating condition setting method for an injection molding machine, which can variably set respective operating conditions for an injection molding operation of an injection molding machine without rewriting a numerical control program for controlling the injection molding operation.The numerical control program is formed using macro parameters which describe the respective operating conditions. The set values of the respective operating conditions are set for corresponding macro parameters. The set values are stored at predetermined addesses in a memory (4) which are assigned to the macro parameters. During injection, the corresponding macro parameters in the program are read out of memory (4) so that the machine is controlled in accordance with the set values.

Abstract: An error detector for various set values is provided which is incorporated in an injection-molding machine of a type controlled by a numerical control unit (1).In order to prevent wrong operations of the injection-molding machine due to setting errors of set values, in the error detector, discrimination means (3) determines whether set values of various items of forming conditions, inputted through input means (14), fulfill requirements related to the items. If the inputted set values fulfill the requirements, they are stored in memory means (6). If not, an alarm is delivered.

Abstract: A metering apparatus which can perform accurate metering is provided in an injection molding machine having a screw rotating motor and an injection servo motor. A screw position (SP), based on an output supplied from a position detector is provided to the injection servo motor and is compared with a deceleration start position (SCBK-l), which is set slightly before a preset metering point (SCBK). When it is determined that the screw has reached the deceleration start position, the screw rotating motor is slowed down. Thereafter, when it is determined that the screw has reached the preset metering point, driving of the screw rotating motor is stopped.

Abstract: A drive control device of an injection molding machine which uses a servo motor (M1, M2, M3) as a drive source. The drive control device can prevent the injection molding machine from becoming uncontrollable when the serve performance of the servo motor is degraded, and prevent the operation speeds of the respective functions of the injection molding machine from exceeding a preset value. The servo motor (M1, M2, M3) is driven in accordance with an output from a servo circuit (10, 11, 12) including an error register (21) for storing a difference between a move command (a) from a control unit (1) and an actual shift amount (b) of the servo motor. When a value stored in the error register is read out by the control unit, it is compared with a predetermined value, and if discriminated to exceed the predetermined value, supply of the move command from the control unit is temporarily stopped.

Abstract: Disclosed is a switching control system for a unit torque limit value of an injection molding machine servo motor (M) to limit a torque instruction (e) supplied from a servo circuit (8) to the servo motor (M) so as to optimize an injection pressure, a holding pressure, and a back pressure.During metering as compared with injection, an output level of a D/A converter (9) for receiving the torque limit instruction (g) is set to be smaller by a predetermined value to reduce the unit torque limit level. A unit torque limit value of the back pressure during metering is set to be smaller than the unit torque limit value for injection and holding pressures during injection, thereby setting smaller torque limit values during metering in units of smaller values as compared with the case of injection.