CN-119573555-B - In-situ measurement method for form and position tolerance of large-size annular part

CN119573555BCN 119573555 BCN119573555 BCN 119573555BCN-119573555-B

Abstract

The invention discloses an in-situ measurement method of the form and position tolerance of a large-size annular part, which belongs to the technical field of detection and is used for in-situ measurement of large-size annular optical and mechanical parts, and comprises the steps of (1) calibrating the precision of a numerical control machining center by using a scale, a laser interferometer and a standard ball; the method comprises the steps of (1) measuring and debugging a workpiece to be parallel and concentric with a turntable by using an indicator, (3) establishing a workpiece coordinate system by using a laser tracker to measure workpiece parameters, (4) measuring outline parameters of a part by using the laser tracker in combination with a machine tool, and (5) analyzing geometric quantity shape and position errors of the part. The method solves the problem of in-situ measurement in the processing process of the large-size annular workpiece, reduces the risk and cost of repeated transportation and inspection of the workpiece, and has the characteristics of convenience in operation, safety, high efficiency, high measurement precision and the like.

Inventors

YANG JIE
LI JIE
CHEN LIN
LUO PING
JIA YUTING

Assignees

中国科学院光电技术研究所

Dates

Publication Date: 20260512
Application Date: 20241212

Claims (2)

1. The in-situ measurement method for the form and position tolerance of the large-size annular part is characterized by comprising the following steps of: step one, calibrating and correcting the axis precision of the numerical control machining center X, Y, Z, C; step two, the debugging workpiece is parallel and concentric with the rotary worktable; step three, measuring workpiece parameters to establish a workpiece coordinate system; measuring the space points of the outer contour of the annular opening plane, the outer cylindrical surface and the inner cylindrical surface of the workpiece; fifthly, data processing, analyzing form and position tolerance, judging the deviation direction of the form and position error of the workpiece according to a coordinate system, and carrying out reworking and detection until the requirement is met; Firstly, detecting and correcting straightness of a linear motion shaft of a numerical control machining center X, Y, Z and perpendicularity of a machine tool workbench by using a standard ruler and an angle square before machining the workpiece, secondly, detecting and correcting positioning and repeated positioning accuracy of the linear motion shaft of X, Y, Z by using a laser interferometer, calibrating and correcting positioning and repeated positioning accuracy of a rotary workbench C shaft of the numerical control machining center by using an auto-collimator, and finally calibrating shaking error of the rotary workbench shaft by using a standard ball, wherein the standard ball is fixed to the rotary workbench center, a standard ball fulcrum is positioned on an upper end face of a cylindrical tool with the height of more than 200mm and the diameter of 50mm, the lower end face of the cylindrical tool is fixed to a three-dimensional adjusting mechanism and synchronously mounted to the rotary workbench center, and measuring and debugging the standard ball and the rotary workbench to be concentric by using an indicator; Fixing a main shaft of a numerical control machining center by using an indicator, enabling a measuring head of the indicator to be in plane contact with a workpiece ring opening, controlling a rotary table to rotate to 0 degree, 120 degrees and 240 degrees respectively to record the jumping difference value of the indicator, debugging a workpiece to be parallel to the rotary table, enabling the measuring head of the indicator to be in contact with an outer cylindrical surface of the workpiece, controlling the rotary table to rotate to 0 degree, 180 degrees, 90 degrees and 270 degrees respectively to record the jumping difference value of the indicator in sequence, and debugging the workpiece to be concentric with the rotary table, wherein the bottom of the workpiece is supported by a three-dimensional adjusting mechanism, and accurately aligning the workpiece through translation and inclination functions; dividing the ring opening plane and the outer circle into 16 points in the circumferential direction, measuring and fitting the flatness and the circle center by using a laser tracker, measuring a straight line between the X target point structure and the circle center point, and establishing a Cartesian coordinate system of the workpiece; Controlling a rotary workbench to drive a workpiece to move to an initial position, fixing a laser tracker target and an indicator on a main shaft of a numerical control machining center, controlling the rotary workbench to rotate at equal intervals of 22.5 degrees, synchronously controlling the main shaft of the numerical control machining center to drive the indicator to contact with a ring opening plane, measuring and recording displacement information by using the laser tracker, and sequentially completing acquisition of the ring opening plane, an outer cylindrical surface and an inner cylindrical surface measuring point, wherein the laser tracker adopts an IFM interference stable point measuring mode, the rotary workbench rotates for 2 circles before measuring, and eliminates return errors, the measuring sequence takes +X target points as starting points, firstly, the ring opening plane is uniformly divided into 16 coordinate points in the circumferential direction, secondly, the outer cylindrical surface is measured, 5 circles are uniformly distributed, each circle is uniformly divided into 16 coordinate points in the circumferential direction, 80 measuring points are uniformly distributed according to each circle, the Z-direction measuring sequence is from the first circle measuring point to the fifth circle measuring point, and finally 80 measuring points are measured; The contact force measurement of the indicator is kept consistent, the measuring points are increased and decreased according to the size and the precision of the workpiece, and the inner cylindrical surface and the outer cylindrical surface are measured according to the distribution of cylindrical plain wires or spiral wires.
2. The method for measuring the geometric tolerance of the large-size annular part in situ according to claim 1, wherein in the fifth step, 16 coordinate points (x, y, z) of the annular opening plane are derived and converted into cylindrical coordinate values through data processing, 16 lines of an inner cylindrical surface and an outer cylindrical surface are respectively derived, 80 contour coordinate points (x, y, z) are respectively converted into inner cylindrical coordinate values and outer cylindrical coordinate values through data processing, the inner cylindrical coordinate values and the outer cylindrical coordinate values are input into SA software of a laser tracker, and all geometric errors of cylindricity, perpendicularity, coaxiality and flatness are fitted and analyzed under a unified reference coordinate system, if an out-of-tolerance term is adopted, the deviation direction is judged under the coordinate, and the deviation direction is reworked and detected until the requirement is met.

Description

In-situ measurement method for form and position tolerance of large-size annular part Technical Field The invention belongs to the technical field of detection, and particularly relates to an in-situ measurement method for form and position tolerance of a large-size annular part. Background The large-size optical and mechanical parts are core components of large-size photoelectric equipment, and have the characteristics of large size, large mass, high precision and the like, and because the core components are more in shape and position parameter indexes and higher in precision, each parameter index needs to be repeatedly matched with processing and detection for many times in the development process to meet the technical requirements, and meanwhile, the index detection aspect needs to be applied to a large-size metering three-coordinate measuring machine to finish relevant precise detection work, so that the detection cost is too high, the transportation and inspection risks of repeatedly lifting parts are larger, and the detection and debugging time is uncontrollable. Disclosure of Invention The method for measuring the shape and position tolerance of the large-size annular part in situ is provided for solving the problem that the shape tolerance is required to be measured in situ in the development process of the large-size annular optical machine part with the size of more than 2 m. The invention solves the problem of in-situ detection of geometric parameters of large-size optical machine parts by means of a gantry machining center and a precise rotary workbench and combining with the space measurement technology of a laser tracker, has better detection precision and accuracy, effectively reduces the development period and risk of products and saves the time cost. The technical scheme adopted by the invention is that the method for measuring the form and position tolerance of the large-size annular part in situ comprises the following steps: step one, calibrating and correcting the axis precision of the numerical control machining center X, Y, Z, C; step two, the debugging workpiece is parallel and concentric with the rotary worktable; step three, measuring workpiece parameters to establish a workpiece coordinate system; measuring the space points of the outer contour of the annular opening plane, the outer cylindrical surface and the inner cylindrical surface of the workpiece; And fifthly, data processing, analyzing form and position tolerance, judging the deviation direction of the form and position error of the workpiece according to a coordinate system, and carrying out reworking and detection until the requirement is met. Compared with the prior art, the invention has the advantages that: (1) The traditional three-coordinate measuring machine is not suitable for in-situ detection of optical and mechanical parts because of being limited by the measuring principle, the measuring range and the higher requirements of the measuring environment, and meanwhile, the equipment acquisition cost is higher, the purchasing, installation and debugging are longer, the application period is longer, the risk of part reciprocating transportation and detection is larger, and the development period is uncontrollable. The precision is lost by using a station-switching mode of the laser tracker, and only the measurement of the external relevant parameters of the workpiece can be completed. The laser tracker is combined with the gantry numerical control machining center, so that the high-precision index on-site detection of the geometric tolerance of the precise optical and mechanical parts is solved, on-site guiding machining is realized, and the measuring head distance between the target center and the indicator is calibrated, so that the synchronous measurement of the outline dimension tolerance of the workpiece can be completed. Therefore, the invention reduces the huge risk of lifting and transporting the precision optical and mechanical parts back and forth, shortens the development period of the stage, and has good detection precision and accuracy; (2) The detection method is convenient to operate, safe, efficient and relatively low in cost; (3) The detection method is not limited to be used for in-situ detection of the geometric tolerance of large-caliber optical elements and precise machinery, and can be also applied to in-situ detection of the dimension and geometric tolerance of large-scale precise special material products in various industries. Drawings FIG. 1 is a flow chart of an in-situ measurement method for geometric tolerances of large-size annular parts; FIG. 2 is a diagram of a numerically controlled machining center; FIG. 3 is a schematic diagram of a table precision calibration of an in-situ measurement method for the form and position tolerance of a large-size annular part; FIG. 4 is a schematic diagram of an implementation of an in-situ measurement method for geometric tolerances of large-size an