Automatic turning compensation method for annular casing part

Abstract

The invention discloses an automatic turning compensation method for an annular casing part. The method comprises the following steps: preparing three types of measuring heads; clamping and aligning the part; machine tool precision calibration; selecting a measurement reference point, and calibrating a measuring head; measuring the feature points, determining a difference value between a measured value and a theoretical value, and endowing the difference value with a compensation variable; a coordinate system compensation program segment is embedded in the part finish machining program; finish machining of the part is completed; performing online measurement; and carrying out three-coordinate measurement. According to the invention, the full-characteristic measurement of the molded surface of the inner cavity of the part is realized by configuring various measuring heads, and the consistency of the measurement precision is ensured by formulating a measurement and calibration scheme aiming at the problems of zero drift, cutter back-off, calibration precision deviation between the measuring heads and the like in the machining process of a machine tool; by establishing the corresponding relation between the online measurement result of the machine tool and the three-coordinate measurement result, the online measurement precision can be corrected in time, so that high-precision automatic machining of the inner cavity profile of the complex structure of the annular case part is achieved, the automatic machining capacity is improved, and meanwhile the stability of the part machining quality is guaranteed.

Description

Technical Field

[0001] The invention belongs to the technical field of aviation engine parts manufacturing, and in particular relates to an automatic lathe processing compensation method for an annular casing part. Background Art

[0002] For the annular casing parts of aircraft engines, they have thin walls, complex inner cavity surface structure, and high processing precision requirements. In the machining process, the parts will inevitably have certain deformation. Therefore, repeated dimensional measurements during the machining process of the parts cannot make the parts qualified in one go, and the online probes configured by CNC machine tools are also difficult to measure all the key features of the inner cavity surface of the parts, resulting in the current situation of difficult automatic processing of parts. Summary of the invention

[0003] In view of the problems existing in the prior art, the present invention provides an automatic lathe compensation method for an annular casing part. By configuring a variety of probes, full-feature measurement of the inner cavity surface of the part is achieved. For the problems of zero point drift, tool letting, calibration accuracy deviation between probes, etc. existing in the machine tool processing process, the consistency of measurement accuracy is ensured by formulating measurement and calibration plans. By establishing a corresponding relationship between the online measurement results of the machine tool and the three-coordinate measurement results, the online measurement accuracy can be corrected in time, thereby achieving high-precision automatic processing of the inner cavity surface of the complex structure of the annular casing part, improving the automatic processing capability while ensuring the stability of the part processing quality.

[0004] In order to achieve the above-mentioned purpose, the present invention adopts the following technical scheme: a method for automatic machining compensation of an annular casing part, comprising the following steps:

[0005] Step 1: Prepare three types of probes, namely vertical ball-end probe, horizontal ball-end probe and horizontal hook-end probe;

[0006] Step 2: Clamp the part onto the machine tool, and then align the part so that the center line of the inner cavity surface of the part coincides with the rotation center line of the machine tool worktable;

[0007] Step 3: Prepare the machine tool precision calibration procedure;

[0008] Step 4: Using the outer surface of the part as the reference plane, use a vertical ball-end probe to measure the coordinate value of the center line of the inner cavity surface of the part;

[0009] Step 5: Compare the coordinate point of the measured center line of the inner cavity surface of the part with the coordinate value of the origin of the machine tool processing coordinate system. If the two coordinate values ​​are the same, the machine tool precision calibration program will not be started. If the two coordinate values ​​are different, the machine tool precision calibration program will be started until the two coordinate values ​​are the same.

[0010] Step 6: Select a measurement reference point on the inner cavity surface of the part, and use a vertical ball-end probe to measure the coordinate value of the measurement reference point;

[0011] Step 7: Use the horizontal ball-end probe to re-measure the coordinate value of the selected measurement reference point, and use the coordinate value measured this time as the reference value to calibrate the length of the horizontal ball-end probe;

[0012] Step 8: Select a series of feature points to be measured on the inner surface of the part, and measure these feature points using a calibrated horizontal ball-end probe;

[0013] Step 9: Determine the difference between the measured value and the theoretical value of these feature points, and assign compensation variables to the difference;

[0014] Step 10: For the remaining feature points that cannot be measured using the horizontal ball-end probe, replace the horizontal ball-end probe with a horizontal hook-end probe after the horizontal ball-end probe is used up.

[0015] Step 11: Use the horizontal hook-end probe to re-measure the coordinate value of the selected measurement reference point, and use the coordinate value measured this time as the reference value to calibrate the length of the horizontal hook-end probe;

[0016] Step 12: Use the calibrated horizontal hook-end probe to measure the remaining feature points;

[0017] Step 13: Determine the difference between the measured value and the theoretical value of these feature points, and assign compensation variables to the difference;

[0018] Step 14: Compile a coordinate system compensation program segment, and embed the compiled coordinate system compensation program segment into the part finishing program. The compensation variables of all feature points correspond to the actual measured differences.

[0019] Step 15: Start the part finishing program and complete the part finishing;

[0020] Step 16: Use a vertical ball-end probe, a horizontal ball-end probe, and a horizontal hook-end probe to re-measure all feature points on the finished parts online to ensure that the measurement results meet the qualified standards;

[0021] Step 17: Transfer the finished parts to the three-dimensional coordinate measuring machine, which will measure all the feature points on the parts again. Then, compare the online measurement data of the machine tool with the three-dimensional coordinate measurement data of the parts, and verify again to ensure that the measurement results meet the qualified standards.

[0022] Beneficial effects of the present invention:

[0023] The automatic lathe compensation method for annular casing parts of the present invention realizes full-feature measurement of the inner cavity surface of the part by configuring a variety of probes. In view of the problems such as zero point drift, tool letting, and calibration accuracy deviation between probes in the machine tool processing process, the consistency of measurement accuracy is ensured by formulating measurement and calibration plans. By establishing a corresponding relationship between the online measurement results of the machine tool and the three-coordinate measurement results, the online measurement accuracy can be corrected in time, thereby realizing high-precision automatic processing of the inner cavity surface of the complex structure of the annular casing parts, improving the automatic processing capability while ensuring the stability of the part processing quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a partial structural schematic diagram of the annular casing parts in the embodiment;

[0025] Figure 2 is a schematic structural diagram of a vertical ball-end probe in an embodiment;

[0026] Figure 3 It is a schematic structural diagram of a horizontal ball-end probe in an embodiment;

[0027] Figure 4 It is a schematic diagram of the structure of the horizontal hook-end probe in the embodiment; DETAILED DESCRIPTION

[0028] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0029] A method for automatic machining compensation of an annular casing part comprises the following steps:

[0030] Step 1: Prepare three types of probes, namely Figure 2 The vertical ball-end probe shown in Figure 1, Figure 3 The horizontal ball-end probe 2 shown and Figure 4 The horizontal hook-end probe 3 shown;

[0031] Step 2: Figure 1 The parts shown are clamped on the machine tool, and then the parts are aligned so that the center line of the inner cavity surface of the parts coincides with the rotation center line of the machine tool worktable;

[0032] Step 3: Prepare the machine tool precision calibration procedure;

[0033] Step 4: Using the outer surface of the part as the reference surface, use the vertical ball-end probe 1 to measure the coordinate value of the center line of the inner cavity surface of the part; in this embodiment, the reference surface is Figure 1 ① dimension surface in the figure;

[0034] Step 5: Compare the coordinate point of the measured center line of the inner cavity surface of the part with the coordinate value of the origin of the machine tool processing coordinate system. If the two coordinate values ​​are the same, the machine tool precision calibration program will not be started. If the two coordinate values ​​are different, the machine tool precision calibration program will be started until the two coordinate values ​​are the same.

[0035] Step 6: Select a measurement reference point on the inner cavity surface of the part, and use the vertical ball-end probe 1 to measure the coordinate value of the measurement reference point; in this embodiment, the measurement reference point is Figure 1 ②Size feature point in the figure;

[0036] Step 7: Use the horizontal ball-end probe 2 to re-measure the coordinate value of the selected measurement reference point, and use the coordinate value measured this time as the reference value to calibrate the length of the horizontal ball-end probe 2;

[0037] Step 8: Select a series of feature points to be measured on the inner surface of the part, and measure these feature points using the calibrated horizontal ball-end probe 2; in this embodiment, the feature points that can be measured by the horizontal ball-end probe 2 are: Figure 1 ⑤Size feature point in the figure;

[0038] Step 9: Determine the difference between the measured value and the theoretical value of these feature points, and assign compensation variables to the difference;

[0039] Step 10: For the remaining feature points that cannot be measured by the horizontal ball-end probe 2, after the horizontal ball-end probe 2 is used up, the horizontal ball-end probe 2 is replaced with a horizontal hook-end probe 3;

[0040] Step 11: Use the horizontal hook-end probe 3 to re-measure the coordinate value of the selected measurement reference point, and use the coordinate value measured this time as the reference value to calibrate the length of the horizontal hook-end probe 3;

[0041] Step 12: Use the calibrated horizontal hook-end probe 3 to measure the remaining feature points; in this embodiment, the feature points that can be measured by the horizontal hook-end probe 3 are Figure 1 ④ and ⑥ of the dimension feature points;

[0042] Step 13: Determine the difference between the measured value and the theoretical value of these feature points, and assign compensation variables to the difference;

[0043] Step 14: Compile a coordinate system compensation program segment, and embed the compiled coordinate system compensation program segment into the part finishing program. The compensation variables of all feature points correspond to the actual measured differences.

[0044] Step 15: Start the part finishing program and complete the part finishing;

[0045] Step 16: Use the vertical ball-end probe 1, the horizontal ball-end probe 2 and the horizontal hook-end probe 3 to re-measure all feature points on the finished parts online to ensure that the measurement results meet the qualified standards;

[0046] Step 17: Transfer the finished parts to the three-dimensional coordinate measuring machine, which will measure all the feature points on the parts again. Then, compare the online measurement data of the machine tool with the three-dimensional coordinate measurement data of the parts, and verify again to ensure that the measurement results meet the qualified standards.

[0047] The solutions in the embodiments are not intended to limit the protection scope of the present invention. All equivalent implementations or changes that do not deviate from the present invention are included in the protection scope of the present invention.

Claims

1. A method for automatic machining compensation of an annular casing part, characterized in that: The steps include: Step 1: Prepare three types of probes, namely vertical ball-end probe, horizontal ball-end probe and horizontal hook-end probe; Step 2: Clamp the part onto the machine tool, and then align the part so that the center line of the inner cavity surface of the part coincides with the rotation center line of the machine tool worktable; Step 3: Prepare the machine tool precision calibration procedure; Step 4: Using the outer surface of the part as the reference plane, use a vertical ball-end probe to measure the coordinate value of the center line of the inner cavity surface of the part; Step 5: Compare the coordinate point of the measured center line of the inner cavity surface of the part with the coordinate value of the origin of the machine tool processing coordinate system. If the two coordinate values ​​are the same, the machine tool precision calibration program will not be started. If the two coordinate values ​​are different, the machine tool precision calibration program will be started until the two coordinate values ​​are the same. Step 6: Select a measurement reference point on the inner cavity surface of the part, and use a vertical ball-end probe to measure the coordinate value of the measurement reference point; Step 7: Use the horizontal ball-end probe to re-measure the coordinate value of the selected measurement reference point, and use the coordinate value measured this time as the reference value to calibrate the length of the horizontal ball-end probe; Step 8: Select a series of feature points to be measured on the inner surface of the part, and measure these feature points using a calibrated horizontal ball-end probe; Step 9: Determine the difference between the measured value and the theoretical value of these feature points, and assign compensation variables to the difference; Step 10: For the remaining feature points that cannot be measured using the horizontal ball-end probe, replace the horizontal ball-end probe with a horizontal hook-end probe after the horizontal ball-end probe is used up. Step 11: Use the horizontal hook-end probe to re-measure the coordinate value of the selected measurement reference point, and use the coordinate value measured this time as the reference value to calibrate the length of the horizontal hook-end probe; Step 12: Use the calibrated horizontal hook-end probe to measure the remaining feature points; Step 13: Determine the difference between the measured value and the theoretical value of these feature points, and assign compensation variables to the difference; Step 14: Compile a coordinate system compensation program segment, and embed the compiled coordinate system compensation program segment into the part finishing program. The compensation variables of all feature points correspond to the actual measured differences. Step 15: Start the part finishing program and complete the part finishing; Step 16: Use a vertical ball-end probe, a horizontal ball-end probe, and a horizontal hook-end probe to re-measure all feature points on the finished parts online to ensure that the measurement results meet the qualified standards; Step 17: Transfer the finished parts to the three-dimensional coordinate measuring machine, which will measure all the feature points on the parts again. Then, compare the online measurement data of the machine tool with the three-dimensional coordinate measurement data of the parts, and verify again to ensure that the measurement results meet the qualified standards.

Images