An injection molding machine is provided that includes a clamping force sensor that detects a clamping force of a mold, and a clamping force monitoring unit that monitors a detected value of the clamping force sensor and calculates a first mold open distance and/or a second mold open distance. The first mold open distance is calculated based on the difference between the maximum value of the detected values obtained during an injection process and a pressure holding process and the detected value obtained at the start of the injection process. The second mold open distance that is calculated based on the difference between the detected value obtained at the end of the pressure holding process and the detected value obtained at the start of the injection process.

A monitoring apparatus for molds includes a control unit connectable to a first and second sensor associable with the mold and configured for emitting respective signals representative of a deformation parameter and temperature parameter of the mold. The control unit, in order to define an alert condition, is configured for: defining a value of a threshold parameter as a function of the temperature of the mold and comparing such value of the deformation parameter with a value of a threshold parameter defined as a function of the temperature of the mold; or normalizing, at a reference temperature, the value of the deformation parameter determined at the temperature of the mold and comparing a value of a threshold parameter, defined at the reference temperature, with the value of the normalized deformation parameter at the same reference temperature. Also forming the object of the present invention is a monitoring method and a data medium.

A molding injection pressure and a molding clamping force are determined in advance to obtain a parting opening amount, which is a predetermined gap, between a movable mold and a fixed mold of a mold during injection filling. The molding injection pressure and the molding clamping force are determined to obtain a molding injection pressure capable of molding a good product and a mold clamping force capable of molding a good product, respectively, thereby setting a specific molding condition, setting a fast injection speed from the start of injection, which is higher than the injection speed set by the specific molding condition, and setting a fast injection section for continuing the fast injection speed as a fast injection condition, mold-clamping the mold by the molding clamping force during molding, and setting the molding injection pressure to a limit pressure, injecting and filling resin into a mold by the fast injection condition from the start of injection, and injecting and filling resin by the specific molding condition when the fast injection section ends.

A specific mold status Ac is caused in advance in which the interval of an inner portion Xi in the parting plane direction of a parting gap C between a fixed mold 2c and a movable mold 2m during the injection filling is larger than the interval of an outer edge portion Xo and the interval of the outer edge portion Xo is equal to or lower than a predetermined size Ls including 0. A molding injection pressure Pi is set as an injection pressure at which a non-defective product can be molded and a molding mold clamping force Pc is set as a mold clamping force by which a non-defective product can be molded. During the production, a mold 2 is clamped by a molding mold clamping force Pc and the clamped mold 2 is filled with the injected resin R by a molding injection pressure Pi. After a predetermined cooling time Tc has passed, a molded piece G is removed.

A manufacturing apparatus includes an injection cylinder to which molten resin is supplied and which is configured to inject the molten resin, and an injection plunger disposed such that the injection plunger fits in the injection cylinder and moves in a first direction and a second direction opposite to the first direction. The injection cylinder includes a base body configured to contain the molten resin, and a sleeve configured to be detachably attached to the base body. The injection plunger is configured to be inserted into an inner portion of the base body through an opening portion formed in the sleeve and slide on the sleeve.

A plasticizing device includes a plasticizing cylinder and a plasticizing screw arranged in the plasticizing cylinder. The plasticizing screw is rotatable about, and linearly movable along, a longitudinal axis. The plasticizing screw comprises a functioning section. A sensor is arranged in or on the plasticizing cylinder, and a distance to the surface of the functioning section of the plasticizing screw can be measured by the sensor. A detecting device can detect a type of the functioning section and/or an operating state of the functioning section, can detect a distance signal progression by a movement of the functioning section relative to the sensor, can compare the detected distance signal progression with a stored distance signal progression, and can issue a signal representing the type of functioning section and/or the operating state of the functioning section depending on a matching of the detected distance signal progression with a stored distance signal progression.

A shrinkage detection device for a polymer injection molding apparatus detects a shrinkage experienced by an injection molded element for assessing a quality of the molded element. Shrinkage, along with temperature and pressure of the melt within the mold during cooling, indicates a sufficiency of the resulting molded element for intended purposes. Sufficiency includes parameters such as flexibility, shear strength and longevity, and is accurately performed can replace conventional sample testing of molded articles that are expensive and time consuming.

A plasticizing device includes a plasticizing cylinder and a plasticizing screw arranged in the plasticizing cylinder. The plasticizing screw is rotatable about, and linearly movable along, a longitudinal axis. The plasticizing screw comprises a functioning section. A sensor is arranged in or on the plasticizing cylinder, and a distance to the surface of the functioning section of the plasticizing screw can be measured by the sensor. A detecting device can detect a type of the functioning section and/or an operating state of the functioning section, can detect a distance signal progression by a movement of the functioning section relative to the sensor, can compare the detected distance signal progression with a stored distance signal progression, and can issue a signal representing the type of functioning section and/or the operating state of the functioning section depending on a matching of the detected distance signal progression with a stored distance signal progression.

When an injection molding machine performs molding, the mold clamping force on the mold is adjusted on the basis of a mold displacement of the mold or the injection peak pressure and injection foremost position so that the molding is performed without causing flash and by an appropriate mold clamping force with which energy can be reduced. The amount of mold displacement and also the injection peak pressure and the injection foremost position are monitored during automatic operation. If there occurs no mold displacement change exceeding a threshold or if there occurs no injection peak pressure anomaly or injection foremost position anomaly exceeding thresholds, the automatic operation is continued. If the mold displacement change occurs or if the injection peak pressure anomaly and the injection foremost position anomaly occur, the operation of the injection molding machine is stopped.

When an injection molding machine performs molding, the mold clamping force on the mold is adjusted on the basis of a mold displacement of the mold or the injection peak pressure and injection foremost position so that the molding is performed without causing flash and by an appropriate mold clamping force with which energy can be reduced. The amount of mold displacement and also the injection peak pressure and the injection foremost position are monitored during automatic operation. If there occurs no mold displacement change exceeding a threshold or if there occurs no injection peak pressure anomaly or injection foremost position anomaly exceeding thresholds, the automatic operation is continued. If the mold displacement change occurs or if the injection peak pressure anomaly and the injection foremost position anomaly occur, the operation of the injection molding machine is stopped.