Abstract: A method of determining a target value of a state variable includes preparing a mixture of the molding material and the gas with different test values of the state variable, and the mixture is respectively compressed or decompressed. In the compression or decompression step, the state variable of the mixture and/or a further state variable of the mixture is measured directly or indirectly, and determination values of a compression behavior variable characteristic of the compression behavior of the mixture are determined from the measurement values. A criterion directed to a solution state of the gas is checked, and a lowest or highest value of the state variable is deduced at which the gas is in solution in the molding material. The lowest or highest value of the state variable at which the gas is in solution in the molding material is used as the target value.

Abstract: A method of determining a solution state of a gas in a plastic melt used in a plastic shaping method includes: (vi) providing the plastic melt together with the gas in a chamber, (vii) altering—in particular reducing—a volume of the chamber to alter a pressure of the plastic melt together with the gas—in particular increased from a first pressure value to a second pressure value, (viii) introducing the plastic melt into a shaping cavity, (ix) computing at least one compression parameter characteristic of the compression behaviour of the plastic melt, in particular a modulus of compression, from the first pressure value and the second pressure value, and (x) determining from the at least one compression parameter whether the gas is substantially completely dissolved in the plastic melt and/or a solubility limit of the gas in the plastic melt is determined from the at least one compression parameter.

Abstract: A mixing device for producing a plastic melt loaded with propellant, from which a foamed plastic part is producible in a molding machine, includes a mixing chamber, at least one propellant inlet device for feeding propellant into the mixing chamber, an inlet channel for plastic melt, and an output channel for dispensing plastic melt loaded with propellant. A first gas-tight shutoff device is provided for closing the inlet channel, and a second gas-tight shutoff device is provided for closing the output channel.

Abstract: A method of determining a target value of a state variable includes preparing a mixture of the molding material and the gas with different test values of the state variable, and the mixture is respectively compressed or decompressed. In the compression or decompression step, the state variable of the mixture and/or a further state variable of the mixture is measured directly or indirectly, and determination values of a compression behavior variable characteristic of the compression behavior of the mixture are determined from the measurement values. A criterion directed to a solution state of the gas is checked, and a lowest or highest value of the state variable is deduced at which the gas is in solution in the molding material. The lowest or highest value of the state variable at which the gas is in solution in the molding material is used as the target value.

Abstract: A method of determining a solution state of a gas in a plastic melt used in a plastic shaping method includes: (vi) providing the plastic melt together with the gas in a chamber, (vii) altering—in particular reducing—a volume of the chamber to alter a pressure of the plastic melt together with the gas—in particular increased from a first pressure value to a second pressure value, (viii) introducing the plastic melt into a shaping cavity, (ix) computing at least one compression parameter characteristic of the compression behaviour of the plastic melt, in particular a modulus of compression, from the first pressure value and the second pressure value, and (x) determining from the at least one compression parameter whether the gas is substantially completely dissolved in the plastic melt and/or a solubility limit of the gas in the plastic melt is determined from the at least one compression parameter.

Abstract: A mixing device for producing a plastic melt loaded with propellant, from which a foamed plastic part is producible in a molding machine, includes a mixing chamber, at least one propellant inlet device for feeding propellant into the mixing chamber, an inlet channel for plastic melt, and an output channel for dispensing plastic melt loaded with propellant. A first gas-tight shutoff device is provided for closing the inlet channel, and a second gas-tight shutoff device is provided for closing the output channel.