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 time variation of an internal pressure of the molding cavity of a multi-phase injection molding machine is detected and represented as an internal pressure graph. An internal pressure graph recorded during a production cycle that produced an injection molded part satisfying a predefined quality characteristic is used as a reference graph. If the internal pressure graph of the current production cycle exceeds a predefined threshold value, then a current machine parameter is changed so as to adapt an internal pressure graph of a subsequent production cycle to the reference graph. Each phase of the production cycle is assigned its own machine parameter determined to have a significant impact on the quality of the parts produced. The assigned machine parameters are changed in a predefined order in a plurality of production cycles wherein exactly one assigned machine parameter is changed per production cycle.

An injection molding device includes an injection machine, a molding die, and a high frequency oscillation device. The injection machine injects a resin material containing a dielectric heat generating material while keeping fluidity by temperature control. The molding die includes a cavity being a channel of flow of the resin material, and a pair of electrodes, each of which faces the cavity, the pair of electrodes being disposed to sandwich the resin material therebetween in a direction crossing a direction of the flow. The high frequency oscillation device applies a high frequency alternate-current voltage to the pair of electrodes.

A method of molding a thermosetting resin, in particular of the epoxy resin type, in which a first mold is filled with the resin while causing the temperature of the resin to vary in application of a first temperature program, without exceeding the Tg of the resin. After the first mold has been filled, the resin is put under pressure while causing the temperature of the resin to vary in application of a second temperature program, without exceeding Tg, and a drop in the pressure exerted by the resin on the mold is detected with the instant at which this pressure presents a break of slope being identified as the instant t1. A second mold is filled with the thermosetting resin in application of the first temperature program. After the second mold has been filled, the resin is put under pressure in application of the second temperature program until an instant t2 close to t1. As from t2, the temperature of the resin is increased to exceed Tg.

Non-time dependent calculated variables based on measured strain are used to effectively determine an optimal hold profile for an expanding crosslinking polymer part in a mold cavity. A system and/or approach may first inject molten expanding crosslinking polymer into a mold cavity, then measure strain at the mold cavity or at another location within the injection molding system, and then calculate at least one non-time dependent variable during an injection molding cycle. Next, the system and/or method commences a hold profile for the part, and upon completing the hold profile, the part is ejected from the mold cavity, whereupon a cure profile is commenced.

A time variation of an internal pressure of the molding cavity of a multi-phase injection molding machine is detected and represented as an internal pressure graph. An internal pressure graph recorded during a production cycle that produced an injection molded part satisfying a predefined quality characteristic is used as a reference graph. If the internal pressure graph of the current production cycle exceeds a predefined threshold value, then a current machine parameter is changed so as to adapt an internal pressure graph of a subsequent production cycle to the reference graph. Each phase of the production cycle is assigned its own machine parameter determined to have a significant impact on the quality of the parts produced. The assigned machine parameters are changed in a predefined order in a plurality of production cycles wherein exactly one assigned machine parameter is changed per production cycle.

Non-time dependent measured variables are used to effectively determine an optimal ejection time of a part from a mold cavity. A system and/or approach may first measure at least one non-time dependent variable during an injection molding cycle. The part is ready to be ejected from the mold upon the measured variable reaching a threshold value indicative of, for example, a part temperature dropping below an activation temperature.

A molding injection pressure Pi with which a parting opening Lm is formed between a movable mold 2m and a fixed mold 2c during injection-filling and which allows formation of a good molded article is obtained and set in advance. A molding clamping force Pc that allows formation of a good molded article is obtained and set in advance. During production, a mold clamping device Mc is clamped with the molding clamping force Pc, and an injection device Mi to apply the molding injection pressure Pi as a limit pressure Ps is driven to injection-fill a mold 2 with resin R. A parting opening detector 3 that detects the parting opening Lm is provided. During production, reset control is executed to reset the parting opening detector 3 to zero if reset timing tr set in advance has come at least on condition that given preparation for injection is completed after clamping. The reset timing is set in a range covering a given period Zs before injection start time and the given period Zs after the injection start time.

An injection molding method of a resin molded article closes a first die and a second die by a predetermined clamping force, conducts pressure holding and cooling after filling a cavity formed between the first die and the second die with a molten resin, and opens the first die and the second die. The injection molding method conducts clamping, filling, pressure holding, and cooling for the first die and the second die by a clamping force previously specified on the basis of a sample with which pressure in the cavity during a cooling process indicates a minimum and which is specified from samples of clamping forces.