A method is described for operating an injection moulding machine, which has one or more movable machine parts which can be moved by suitable drives along specifiable travelling distances. Movement of a movable machine part is repeated cyclically. In order to reduce the movement times of the movable machine parts to a minimum, provision is made for one or more of the movable machine parts to successively reduce the power reserves of one or more of the drives associated with a movable machine part, until a specifiable minimum of power reserve is reached, wherein the minimum can be zero. In each cycle, the power reserve of the drive or drives is determined and is successively reduced, in particular from cycle to cycle. A movable platen, an ejector, a core puller, a plasticizing screw and/or an injection piston can be provided as movable machine part.