Abstract: Embodiments of the present disclosure provide a datum selection method for minimizing hole position errors in group hole machining of large components, comprising: 1) determining a type of a computer numerical control (CNC) machine tool and establishing a topological structure of the CNC machine tool; 2) establishing a theoretical postural model of a tool center point during a motion; 3) establishing a hole position error model; 4) establishing an average error model of hole positions in group hole machining; and 5) obtaining a machining datum for group holes of corresponding components. For the skeleton and skinned group hole machining of aircraft components, different principles of datum selection are provided respectively, which can effectively improve the positional accuracy of the skeleton or skinned group hole machining, at the same time provides a more scientific and reasonable approach for the datum selection in group hole machining of large components.

Abstract: The embodiment of the present disclosure provides a method for quickly optimizing geometric error compensation data of a translational axis of a five-axis numerically controlled machine tool. The method includes: 1) establishing a volumetric positioning error model; 2) establishing an error database; 3) constructing a volumetric error compensation table; 4) establishing a compensation data optimization model to form an optimization model of three face diagonals and one body diagonal in a translational axis linkage mode; 5) completing iterative optimization and selection of the correction coefficients; 6) completing compensation of the geometric errors of the five-axis numerically controlled machine tool; and 7) iterating error correction data to the error database, performing linkage trajectory detection, presetting a positioning error threshold, and cycling the operations 2) to 6) to realize a machine tool precision guarantee system for periodic detection, optimization, and compensation.

Abstract: Embodiments of the present disclosure provide a method of fast optimization and compensation for volumetric positioning errors of rotary axes of a five-axis CNC system machine tool. The method comprises: establishing a volumetric positioning error model; forming an error database containing 12 geometrical error vectors; constructing a volumetric positioning error compensation table; establishing a compensation value optimization model; completing an iterative optimization of compensation values of volumetric positioning errors; generating a volumetric positioning error compensation file for a CNC system to complete compensation for the volumetric positioning errors; and updating the error database, detecting linkage trajectories of the rotary axes, and setting a linkage trajectory positioning error threshold, and guaranteeing accuracy by iteratively implementing detection, optimization, and compensation.

Abstract: Disclosed are a self-positioning assembly system for rapid assembly of an aircraft and a method thereof. The self-positioning assembly system includes a mounting platform, a framework assembly, a hole positioner assembly, a strut positioner assembly and a pallet assembly. The framework assembly is mounted on the mounting platform and includes a hole positioner column and a pallet column, the hole positioner assembly is arranged on the hole positioner column, the pallet assembly is arranged on the pallet column, a plurality of the hole positioner columns are respectively arranged on both sides of the mounting platform, and a plurality of the pallet columns are arranged in a middle of the mounting platform.

Abstract: Embodiments of the present disclosure provide a datum selection method for minimizing hole position errors in group hole machining of large components, comprising: 1) determining a type of a computer numerical control (CNC) machine tool and establishing a topological structure of the CNC machine tool; 2) establishing a theoretical postural model of a tool center point during a motion; 3) establishing a hole position error model; 4) establishing an average error model of hole positions in group hole machining; and 5) obtaining a machining datum for group holes of corresponding components. For the skeleton and skinned group hole machining of aircraft components, different principles of datum selection are provided respectively, which can effectively improve the positional accuracy of the skeleton or skinned group hole machining, at the same time provides a more scientific and reasonable approach for the datum selection in group hole machining of large components.

Abstract: A clamping device and a machining method. The clamping device comprises: a base; a clamping head comprising a blind rivet and a locking member, the blind rivet comprising a middle column segment and enlarged portions at two ends, and the locking member being connected to an upper end of the blind rivet and defining a clamping opening; a lower cavity connected to the base; an upper cavity comprising an annular peripheral wall and a top wall having a central hole, the top wall being clamped between the two enlarged portions, the middle column segment of the blind rivet movably passing through the central hole, and the upper cavity being connected to the lower cavity in a fit manner; an elastic member located in the peripheral wall and supported between the enlarged portion at a lower portion of the blind rivet and the top wall; and a support cylinder movably fitted in the lower cavity, the support cylinder being supported below the elastic member.

Abstract: A tool path generation method for a bidirectional cutting edge tool, comprising: first obtaining a driving line and an auxiliary driving line of a contour, and discretizing the driving line to obtain tool position driving points; obtaining a tool axis vector according to a rule plane of the driving points and the auxiliary driving line; and then, calculating a tool position point according to geometric dimensions of the tool so as to obtain a tool path of a machining contour of the bidirectional cutting edge tool. The problems of fiber delamination and fluffing, burr generation, and the like of the contour of a machined part can be avoided, and the machining quality of a contour surface is improved, and the low-cost machining of parts can be efficiently achieved.

Abstract: A layered modeling method for laser metal deposition (LIVID) 3D printing. The layered modeling method includes: obtaining estimated printing parameters of each layer in an entire digital model based on a process database; obtaining estimated feature points of each layer through the estimated parameters; comparing estimated feature points of each layer with feature points of a corresponding actual shape to obtain a difference in each layer; and accumulating to obtain a difference in the entire digital model to obtain corresponding printing parameters. The layered modeling method has the advantages of effectively reducing the calculation amount during data comparison and greatly saving time.

Abstract: A layered modeling method for laser metal deposition (LMD) 3D printing. The layered modeling method includes: obtaining estimated printing parameters of each layer in an entire digital model based on a process database; obtaining estimated feature points of each layer through the estimated parameters; comparing estimated feature points of each layer with feature points of a corresponding actual shape to obtain a difference in each layer; and accumulating to obtain a difference in the entire digital model to obtain corresponding printing parameters. The layered modeling method has the advantages of effectively reducing the calculation amount during data comparison and greatly saving time.

Abstract: The present invention relates to an “S” shaped detection test piece for comprehensively detecting the precision of the numerical control milling machine and the detection method thereof. The detection test piece consists of an “S” shaped equal thickness edge strip (1) and a rectangular base (2), respectively forming two “S” shaped curves in two different planes and the projections of which in the base plane (3) cross each other and have open and close angle (?) states formed at the intersection.

Abstract: The present invention relates to an “S” shaped detection test piece for comprehensively detecting the precision of the numerical control milling machine and the detection method thereof. The detection test piece consists of an “S” shaped equal thickness edge strip (1) and a rectangular base (2), respectively forming two “S” shaped curves in two different planes and the projections of which in the base plane (3) cross each other and have open and close angle (?) states formed at the intersection.