Print head for a 3D printer, with improved control

A print head (10) for a 3D printer (1), the print head comprising an infeed zone (11) with a feeding means (12) configured for feeding a starting material (20), a plasticizing zone (14) with a heater (15) and an outlet opening (16) for a liquid phase (22) of the starting material (20), and a conveying apparatus (30) for conveying the starting material (20) from the infeed zone (11) into the plasticizing zone (14), characterized in that the conveying apparatus (30) comprises a plunger (31) configured to be introduced into the infeed zone (11), and

• wherein the print head (10) further comprises a housing (19) including a cooling means (13) for keeping a temperature (Ts) of the infeed zone (11) below a temperature (TP) even when the liquid phase (22) of the starting material (20) exits from the outlet opening (16),
• wherein the cooling means (13) includes:
• an active cooling unit (13a) formed by internal cooling channels surrounding a first portion of the infeed zone (11) and having a flowing cooling medium;
• and
• a passive cooling unit (13b) surrounding a second portion of the infeed zone (11) and formed by cooling fins extending into ambient air surrounding the infeed zone (11), the cooling fins being configured to transfer heat into the ambient air,
• wherein the temperature (TP) is a temperature at which the starting material (20) plasticizes,
• wherein the active cooling unit (13a) and the passive cooling unit (13b) are arranged downstream from where the starting material (20) is introduced into the infeed zone (11), and
• wherein the active cooling unit (13a) is arranged upstream from the passive cooling unit (13b) along a flow direction of the starting material (20).