A mold comprising: first and second mold portions (14a, 14b), each having one or more recesses, wherein the mold portions (14a, 14b) are movable relative to one another between an open position and a closed position in which each of the recess(es) of the first mold portion cooperates with a respective one of the recess(es) of the second mold portion to define a chamber, wherein each of the one or more chambers comprises a first cooling body coupled to the first mold portion and a second cooling body coupled to the second mold portion, wherein a first insert is configured to be removably coupled to the first cooling body and a second insert is configured to be removably coupled to the second cooling body such that, when the first and second inserts (30a, 30b) are respectively removably coupled to the first and second cooling bodies, the first insert and the second insert cooperate to define a mold cavity within the chamber that is configured to receive a thermoplastic material; wherein each of the first and second cooling bodies comprises a thermally-conductive material, each of the first and second cooling bodies comprising opposing first and second faces (56, 58) and an inlet and an outlet, wherein the first face is coupled to one of the mold portions (14a, 14b) and the second face is configured to be removably coupled to one of the first and second inserts (30a, 30b), wherein each of the first and second cooling bodies defines a fluid cavity closer to the second face than the first face, wherein the fluid cavity is in fluid communication with the inlet and the outlet; wherein the chamber(s) comprise two or more chambers, and wherein for each of one or more sets of a plurality of the chambers: the first cooling bodies are in fluid communication with one another via one or more first conduits, each of the first conduit(s) having a first diameter; the second cooling bodies are in fluid communication with one another via one or more second conduits, each of the second conduit(s) having a second diameter; and optionally, the second diameter is at least 20% larger than the first diameter; wherein each of the one or more second cooling bodies is movable within a respective recess of the second mold portion between a first position and a second position in which the second cooling body is closer than when in the first position to the face of the second mold portion that, when the mold portions (14a, 14b) are in the closed position, faces the first mold portion; wherein the mold comprises one or more of the first inserts and one or more of the second inserts wherein each of the first and second inserts (30a, 30b) comprises silicon carbide and, for each of the chamber(s), one of the first insert(s) is coupled to the first cooling body and one of the second insert(s) is coupled to the second cooling body. first and second mold portions (14a, 14b), each having one or more recesses, wherein the mold portions (14a, 14b) are movable relative to one another between an open position and a closed position in which each of the recess(es) of the first mold portion cooperates with a respective one of the recess(es) of the second mold portion to define a chamber, wherein each of the one or more chambers comprises a first cooling body coupled to the first mold portion and a second cooling body coupled to the second mold portion, wherein a first insert is configured to be removably coupled to the first cooling body and a second insert is configured to be removably coupled to the second cooling body such that, when the first and second inserts (30a, 30b) are respectively removably coupled to the first and second cooling bodies, the first insert and the second insert cooperate to define a mold cavity within the chamber that is configured to receive a thermoplastic material; wherein each of the first and second cooling bodies comprises a thermally-conductive material, each of the first and second cooling bodies comprising opposing first and second faces (56, 58) and an inlet and an outlet, wherein the first face is coupled to one of the mold portions (14a, 14b) and the second face is configured to be removably coupled to one of the first and second inserts (30a, 30b), wherein each of the first and second cooling bodies defines a fluid cavity closer to the second face than the first face, wherein the fluid cavity is in fluid communication with the inlet and the outlet; wherein the chamber(s) comprise two or more chambers, and wherein for each of one or more sets of a plurality of the chambers: the first cooling bodies are in fluid communication with one another via one or more first conduits, each of the first conduit(s) having a first diameter; the second cooling bodies are in fluid communication with one another via one or more second conduits, each of the second conduit(s) having a second diameter; and optionally, the second diameter is at least 20% larger than the first diameter; wherein each of the one or more second cooling bodies is movable within a respective recess of the second mold portion between a first position and a second position in which the second cooling body is closer than when in the first position to the face of the second mold portion that, when the mold portions (14a, 14b) are in the closed position, faces the first mold portion; wherein the mold comprises one or more of the first inserts and one or more of the second inserts wherein each of the first and second inserts (30a, 30b) comprises silicon carbide and, for each of the chamber(s), one of the first insert(s) is coupled to the first cooling body and one of the second insert(s) is coupled to the second cooling body.