A processing machine comprising: - a system designed to form an opening (10; 10*; 10**) into and through a security substrate, which opening (10; 10*; 10**) is open on both sides of the security substrate and extends through the security substrate, - a device designed to fill the opening (10; 10*; 10**) with transparent material and thereby form a transparent window (W; W*; W**) in the security substrate, the device comprising: - at least one supporting member (20; 20', 21) with a supporting surface (20A; 21A) against which a first side of the security substrate is applied during a filling of the opening (10; 10*; 10**) with the transparent material in such a way as to block one side of the opening (10; 10*; 10**), wherein the supporting member (20; 20', 21) is a supporting cylinder (20; 20'); and - an application system (A; A') including one or more application units (14; 14', 14", 24) designed to apply the transparent material inside the opening (10; 10*; 10**) from the other side of the security substrate while the first side of the security substrate is applied against the supporting surface (20A; 21A) of the supporting member (20; 20', 21), thereby forming the transparent window (W; W*; W**), wherein the application system (A; A') includes at least one screen-printing unit (14; 14', 14", 24) acting as application unit and designed to apply the transparent material directly or indirectly into the opening (10; 10*; 10**) of the security substrate; - further comprising at least one pressure roller located downstream of the application system (A; A') and designed to press the security substrate against the supporting surface (20A; 21A) of the supporting member (20; 20', 21); - further comprising at least one UV curing unit designed to subject the transparent material to a UV curing operation prior to the security substrate leaving the supporting member (20; 20', 21). - a system designed to form an opening (10; 10*; 10**) into and through a security substrate, which opening (10; 10*; 10**) is open on both sides of the security substrate and extends through the security substrate, - a device designed to fill the opening (10; 10*; 10**) with transparent material and thereby form a transparent window (W; W*; W**) in the security substrate, the device comprising: - at least one supporting member (20; 20', 21) with a supporting surface (20A; 21A) against which a first side of the security substrate is applied during a filling of the opening (10; 10*; 10**) with the transparent material in such a way as to block one side of the opening (10; 10*; 10**), wherein the supporting member (20; 20', 21) is a supporting cylinder (20; 20'); and - an application system (A; A') including one or more application units (14; 14', 14", 24) designed to apply the transparent material inside the opening (10; 10*; 10**) from the other side of the security substrate while the first side of the security substrate is applied against the supporting surface (20A; 21A) of the supporting member (20; 20', 21), thereby forming the transparent window (W; W*; W**), wherein the application system (A; A') includes at least one screen-printing unit (14; 14', 14", 24) acting as application unit and designed to apply the transparent material directly or indirectly into the opening (10; 10*; 10**) of the security substrate; - further comprising at least one pressure roller located downstream of the application system (A; A') and designed to press the security substrate against the supporting surface (20A; 21A) of the supporting member (20; 20', 21); - further comprising at least one UV curing unit designed to subject the transparent material to a UV curing operation prior to the security substrate leaving the supporting member (20; 20', 21).