An optical module for a machine for machining workpieces and/or for producing molded bodies by location-selective solidification of material powder to form connected regions by means of a laser beam, comprising: a housing having means for releasably attaching said optical module to said machine, and a collimation optics changer which is arranged detachably in said housing and includes at least two collimating optics for collimating said laser beam, wherein said collimation optics changer is configured as a turret and is mounted rotatably in said housing via an axis of rotation, and wherein said collimating optics changer comprises: a case; a mechanism for automatically changing the collimating optics; a plurality of cooling channels in the case of said collimation optics changer, through which channels a fluid coolant flows to cool the collimation optics; and means for measuring the temperature of the collimation optics, wherein a first axial cooling channel as a feed for the fluid coolant and a second axial cooling channel as a return for the fluid coolant extend through the axis of rotation, wherein the axial cooling channels are connected to cooling channels extending radially in a first plane outwards through the case of said collimation optics changer, wherein further radial cooling channels extend in a second plane parallel to the first plane through said collimation optics changer, and wherein the radial cooling channels of the two planes are in flow communication with one another via cooling channels extending perpendicularly to the first and second planes through the case of said collimating optics changer in order to provide the coolant circuit. a housing having means for releasably attaching said optical module to said machine, and a collimation optics changer which is arranged detachably in said housing and includes at least two collimating optics for collimating said laser beam, wherein said collimation optics changer is configured as a turret and is mounted rotatably in said housing via an axis of rotation, and wherein said collimating optics changer comprises: a case; a mechanism for automatically changing the collimating optics; a plurality of cooling channels in the case of said collimation optics changer, through which channels a fluid coolant flows to cool the collimation optics; and means for measuring the temperature of the collimation optics, wherein a first axial cooling channel as a feed for the fluid coolant and a second axial cooling channel as a return for the fluid coolant extend through the axis of rotation, wherein the axial cooling channels are connected to cooling channels extending radially in a first plane outwards through the case of said collimation optics changer, wherein further radial cooling channels extend in a second plane parallel to the first plane through said collimation optics changer, and wherein the radial cooling channels of the two planes are in flow communication with one another via cooling channels extending perpendicularly to the first and second planes through the case of said collimating optics changer in order to provide the coolant circuit. a case; a mechanism for automatically changing the collimating optics; a plurality of cooling channels in the case of said collimation optics changer, through which channels a fluid coolant flows to cool the collimation optics; and means for measuring the temperature of the collimation optics, wherein a first axial cooling channel as a feed for the fluid coolant and a second axial cooling channel as a return for the fluid coolant extend through the axis of rotation, wherein the axial cooling channels are connected to cooling channels extending radially in a first plane outwards through the case of said collimation optics changer, wherein further radial cooling channels extend in a second plane parallel to the first plane through said collimation optics changer, and wherein the radial cooling channels of the two planes are in flow communication with one another via cooling channels extending perpendicularly to the first and second planes through the case of said collimating optics changer in order to provide the coolant circuit.