Methods of monitoring and controlling a molding process using a sensed change in strain provided by a strain gauge are provided. A target strain profile is created for a molding process of a molding apparatus. An upper and lower deviation limit from the target strain profile for the molding process is provided. If a sensed change in strain exceeds a deviation limit, an alarm is activated.

To provide a new foam molding method and injection molding machine capable of solving variation in a wall thickness and a foamed state, sensor corrosion, a complexity of sensor positioning, and the like. The above-described problem is solved by a foam molding method comprising a resin filling step of filling a mold (2), clamped by a predetermined mold clamping force (Pc), with a resin (R) at a predetermined molding injection pressure (Pi), a filling stopping step of stopping the filling of the resin (R) when, while monitoring a mold gap (Lm) of the mold (2) during the filling, a predetermined mold gap value set in advance is reached, a surface layer curing and filled resin cooling step of curing a surface layer of the resin (R) for a certain time and cooling the filled resin (R) for a certain time after the filling of the resin (R) is stopped, a volume controlling step of controlling a volume increase by reducing the mold clamping force after curing the surface layer of the resin (R) for a certain time, and a taking out step of taking out a foam-molded product by opening the mold (2) after the volume control is performed and after cooling the filled resin (R) for a certain time.

An open/close counting device to be attached to one of a first die and a second die which constitute a die, the die being opened by relatively moving the first die and the second die, the open/close counting device counting the number of open/close times of the die. The open/close counting device includes an open/close detecting section provided so as to face a target face of the other of the first die and the second die and to detect relative displacement of the target face along a die moving direction in non-contact condition, and includes an output section to output the open/close times counted based on detection of open/close by the open/close detecting section.

A method and apparatus for injection molding of plastic material into a cavity of a mold by means of at least one injector whose opening and closing occurs through an electronic control unit and wherein an undesired opening of the mold caused by any overpressure of the plastic material injected into the cavity of the mold is detected by means of transducers and corrected by means of the electronic control unit. The transducers are arranged outside the cavity of the mold.

To provide a new foam molding method and injection molding machine capable of solving variation in a wall thickness and a foamed state, sensor corrosion, a complexity of sensor positioning, and the like. The above-described problem is solved by a foam molding method comprising a resin filling step of filling a mold (2), clamped by a predetermined mold clamping force (Pc), with a resin (R) at a predetermined molding injection pressure (Pi), a filling stopping step of stopping the filling of the resin (R) when, while monitoring a mold gap (Lm) of the mold (2) during the filling, a predetermined mold gap value set in advance is reached, a surface layer curing and filled resin cooling step of curing a surface layer of the resin (R) for a certain time and cooling the filled resin (R) for a certain time after the filling of the resin (R) is stopped, a volume controlling step of controlling a volume increase by reducing the mold clamping force after curing the surface layer of the resin (R) for a certain time, and a taking out step of taking out a foam-molded product by opening the mold (2) after the volume control is performed and after cooling the filled resin (R) for a certain time.

A method and apparatus for injection molding of plastic material into a cavity of a mold by means of at least one injector whose opening and closing occurs through an electronic control unit and wherein an undesired opening of the mold caused by any overpressure of the plastic material injected into the cavity of the mold is detected by means of transducers and corrected by means of the electronic control unit. The transducers are arranged outside the cavity of the mold.

A method and apparatus for injection molding of plastic material into a cavity of a mold by means of at least one injector whose opening and closing occurs through an electronic control unit and wherein an undesired opening of the mold caused by any overpressure of the plastic material injected into the cavity of the mold is detected by means of transducers and corrected by means of the electronic control unit. The transducers are arranged outside the cavity of the mold.

A display device to be attached to a die, the display device including a display to rewrite and display die management information obtained in an information acquisition section to obtain the die management information for managing the die. The display uses electric power when display content is rewritten, and the display uses no electric power for keeping the display.

A display device to be attached to a die, the display device including a display to rewrite and display die management information obtained in an information acquisition section to obtain the die management information for managing the die. The display uses electric power when display content is rewritten, and the display uses no electric power for keeping the display.

An open/close counting device to be attached to one of a first die and a second die which constitute a die, the die being opened by relatively moving the first die and the second die, the open/close counting device counting the number of open/close times of the die. The open/close counting device includes an open/close detecting section provided so as to face a target face of the other of the first die and the second die and to detect relative displacement of the target face along a die moving direction in non-contact condition, and includes an output section to output the open/close times counted based on detection of open/close by the open/close detecting section.