Printhead assembly for a system for additive manufacturing, wherein the printhead assembly comprises • connection means for connecting the printhead assembly to a positioning system of an AM system; • heat exchanging means (106, 106', 106") attached to the printhead assembly, wherein the heat exchanging means are configured and arranged to establish a releasable clamping connection with a feedstock liquefying unit that is configured to liquefy AM feedstock to accommodate the feedstock liquefying unit in the printhead assembly; wherein • the heat exchanging means (106, 106', 106") are configured to allow actuation thereof for bringing the heat exchanging means (106, 106', 106") to an open state, to allow at least one of disposal of the feedstock liquefying unit and acquisition of a replacement feedstock liquefying unit, and for bringing the heat exchanging means (106, 106', 106") to a closed state, to hold the feedstock liquefying unit, wherein the heat exchanging means (106, 106', 106") comprises a first heat exchanging section and at least one of a second heat exchanging section and a support structure, wherein the support structure is associated with the printhead assembly, wherein • the first heat exchanging section and at least one of the second heat exchanging section and the support structure are configured to allow movement thereof relative to one another; and wherein • at least one of the first heat exchanging section, the second heat exchanging section and the support structure is configured to allow actuation thereof to bring the heat exchanging means (106, 106', 106") to said open state, and wherein • at least one of the first heat exchanging section, the second heat exchanging section and the support structure is configured to allow actuation thereof to bring the heat exchanging means (106, 106', 106") to said closed state; and wherein at least one of the first heat exchanging section and the second heat exchanging section and the support structure is provided with first actuating means, and wherein the first actuating means are arranged to cooperate with a second actuating means of a feedstock liquefying unit storage and a positioning system of an AM system. • connection means for connecting the printhead assembly to a positioning system of an AM system; • heat exchanging means (106, 106', 106") attached to the printhead assembly, wherein the heat exchanging means are configured and arranged to establish a releasable clamping connection with a feedstock liquefying unit that is configured to liquefy AM feedstock to accommodate the feedstock liquefying unit in the printhead assembly; wherein • the heat exchanging means (106, 106', 106") are configured to allow actuation thereof for bringing the heat exchanging means (106, 106', 106") to an open state, to allow at least one of disposal of the feedstock liquefying unit and acquisition of a replacement feedstock liquefying unit, and for bringing the heat exchanging means (106, 106', 106") to a closed state, to hold the feedstock liquefying unit, wherein the heat exchanging means (106, 106', 106") comprises a first heat exchanging section and at least one of a second heat exchanging section and a support structure, wherein the support structure is associated with the printhead assembly, wherein • the first heat exchanging section and at least one of the second heat exchanging section and the support structure are configured to allow movement thereof relative to one another; and wherein • at least one of the first heat exchanging section, the second heat exchanging section and the support structure is configured to allow actuation thereof to bring the heat exchanging means (106, 106', 106") to said open state, and wherein • at least one of the first heat exchanging section, the second heat exchanging section and the support structure is configured to allow actuation thereof to bring the heat exchanging means (106, 106', 106") to said closed state; and • the first heat exchanging section and at least one of the second heat exchanging section and the support structure are configured to allow movement thereof relative to one another; and wherein • at least one of the first heat exchanging section, the second heat exchanging section and the support structure is configured to allow actuation thereof to bring the heat exchanging means (106, 106', 106") to said open state, and wherein • at least one of the first heat exchanging section, the second heat exchanging section and the support structure is configured to allow actuation thereof to bring the heat exchanging means (106, 106', 106") to said closed state; and wherein at least one of the first heat exchanging section and the second heat exchanging section and the support structure is provided with first actuating means, and wherein the first actuating means are arranged to cooperate with a second actuating means of a feedstock liquefying unit storage and a positioning system of an AM system.