A coordinate measuring machine method for detecting rat cage slots

Abstract

This invention discloses a coordinate measuring machine (CMM) method for detecting squirrel cage slots. The method calculates the least common multiple of the standard spacing of the squirrel cage slots and the minimum circumferential indexing accuracy of the CMM, and groups all squirrel cage slots according to this least common multiple. Array measurement is then performed according to the number of groups. This method uses a group-array measurement approach to meet the characteristics of the CMM's circumferential indexing. Through theoretical calculation, the precise number of groups can be calculated, thereby enabling automatic CMM measurement of all squirrel cage slots on a squirrel cage part. After the measurement program is programmed, when measuring the same type of squirrel cage part, only a coarse measurement datum needs to be established, and the measurement program can be called again to achieve automatic measurement, greatly improving the efficiency of part inspection.

Description

Technical Field

[0001] This invention belongs to the field of coordinate measuring machine (CMM) technology, and specifically to a method for grouping and aligning detection of rat cages. Background Technology

[0002] The outer cylindrical surface of a squirrel cage part has multiple radially distributed squirrel cage grooves. These grooves must be measured using a coordinate measuring machine (CMM) to determine their positional accuracy. Due to the limitations of the CMM's indexing structure, the circumferential indexing is done in multiples of 2.5°, 5°, or 7.5°. This results in some squirrel cage grooves lacking a suitable rotation angle for measurement. Without a specific angle for measurement (meaning the circumferential rotation angle of the CMM is not selected as a multiple of 2.5°, 5°, or 7.5°), angular errors in the probe's rotation will be introduced, potentially leading to interference and collision between the probe and the part. For example, in measurement... Figure 1 When the 80 cage slots shown are used, the positional tolerance of references A and B is 0.1, 360° / 80 = 4.5°, which is outside the circumferential indexing range of the three-coordinate measuring machine, making accurate circumferential indexing impossible. Summary of the Invention

[0003] The technical problem to be solved by this invention is that accurate circumferential indexing cannot be performed when the spacing of the squirrel cage slots is not an integer multiple of the minimum circumferential indexing of the three-coordinate machine tool. A grouped array detection method is provided.

[0004] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0005] A method for coordinate measuring machine (CMM) detection of mouse cage slots involves calculating the least common multiple of the standard spacing between the mouse cage slots and the minimum circumferential graduation accuracy of the CMM, grouping all mouse cage slots according to the least common multiple, and then performing array measurements according to the number of groups.

[0006] The specific steps include:

[0007] Let Y / N = X1, 360° / N = X2*Z, and substitute positive integers into N by assignment until X1 and X2 are both integers. At this point, N is the number of mouse cage slots in each group, where Y is the total number of mouse cage slots and Z is the minimum precision of the three-axis circumferential division.

[0008] B divides the rat cages into N groups and places them into a coordinate measuring machine to establish a measurement coordinate system.

[0009] C. Collect the midpoint of each mouse cage in the tested group.

[0010] D rotates the mouse cage groove, and array measurements are performed according to the number of groups N.

[0011] In step B: First, collect the reference features: one face, one circle, and one corner, and establish coordinate system 1. Then, add a safety plane or a moving point, collect the reference features again: one face, one circle, and one corner, and establish coordinate system 2.

[0012] In step C: Collect points on both sides of the edge of each cage slot from the same height, and calculate the midpoint between these two edge points. Determine whether all midpoints meet the positional accuracy requirements.

[0013] The beneficial effects of this invention are:

[0014] This method uses a group-array measurement approach to meet the circumferential indexing characteristics of the coordinate measuring machine. Through theoretical calculation, the precise number of groups can be calculated, thereby realizing the automatic coordinate measuring machine measurement of all cage slots of the cage part. After the measurement program is programmed, when measuring the same type of cage part, only a rough measurement datum needs to be established, and the measurement program can be called again to realize automatic measurement, which greatly improves the inspection efficiency of the part. Attached Figure Description

[0015] Figure 1 This is a simplified sketch of a part of a mouse cage.

[0016] Figure 2 This is a schematic diagram of a collection point in a rat cage trough.

[0017] Figure 3 This is a schematic diagram of the collection points for a set of rat cage troughs.

[0018] Figure 4 This is a simplified diagram of the three-coordinate array.

[0019] Figure 5 This is a simplified diagram after a three-coordinate array. Detailed Implementation

[0020] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.

[0021] Example 1: The basic concept of this scheme is to calculate the least common multiple of the standard spacing of the mouse cage slots and the minimum circumferential graduation accuracy of the coordinate measuring machine, and then group all the mouse cage slots according to the least common multiple; array measurement is then performed according to the number of groups. Specific steps include:

[0022] Let Y / N = X1, 360° / N = X2*Z, and substitute positive integers into N by assignment until X1 and X2 are both integers. At this point, N is the number of mouse cage slots in each group, where Y is the total number of mouse cage slots and Z is the minimum precision of the three-axis circumferential division.

[0023] B divides the rat cages into N groups and places them into a coordinate measuring machine to establish a measurement coordinate system.

[0024] C. Collect the midpoint of each mouse cage in the tested group;

[0025] D rotates the mouse cage groove, and array measurements are performed according to the number of groups N.

[0026] This solution mainly involves the framework for automatic three-coordinate programming, mouse cage slot grouping-array programming, and precise group number calculation methods.

[0027] 2.1 Framework for Automatic Coordinate Measuring Program:

[0028] 1) Collect benchmark elements: one surface, one circle, and one angular direction, and establish coordinate system 1;

[0029] 2) Alt+Z to switch to automatic mode, add a safety plane or moving point to prevent probe collision;

[0030] 3) Collect the reference elements again: one surface, one circle, and one corner, and establish coordinate system 2;

[0031] 4) Collect the measured elements and compile a coordinate measuring machine (CMM) program;

[0032] 5) Evaluation, displaying the test results.

[0033] 2.2 Calculation of the exact number of groups: Research has found that two conditions must be met simultaneously to calculate the optimal number of groups.

[0034] Y / N = X1; (Y: number of mouse cage slots, N: number of groups, X1: integer, 1, 2, 3, 4, ...)

[0035] 360° / N = X2 * Z (N: number of groups, X2: integer, 1, 2, 3, 4..., Z: minimum precision of circumferential division of the three coordinate system, 2.5°, 5° or 7.5°)

[0036] The two formulas above can be used to calculate X1 and X2*Z by substituting N into the formulas, provided that X1 and X2 are both integers.

[0037] 2.3 Grouping and Array Programming of Squirrel Cages: Calculate the minimum number of groups according to the formula in 2.2, and follow steps 1) to 3) in 2.1 to establish the measurement coordinate system; as shown in the figure below, rotate the three coordinates by A-90B0. Collect X1 data from all squirrel cages in the group being measured, and collect one point (point 1, point 2) on each of the left and rear sides of the cage. Then, find the midpoint (point 3) between points 1 and 2. Collect the midpoints of the other cages in the group in the same way. Then, array the cages according to the number of groups N. The system will automatically calculate A-90BX2*Z for all groups (X2: integer, 1, 2, 3, 4..., Z: minimum circumferential resolution of the three coordinates, 2.5°, 5°, or 7.5°). After all operations are completed, the measurement program will run automatically, collect all elements, and finally evaluate the position of the squirrel cages. This method of compiling a coordinate measuring machine program is simple and easy to read. For subsequent identical parts, only a rough datum needs to be established to achieve automatic measurement of the parts. Alternatively, a dedicated measuring fixture can be designed to achieve precise positioning and automatic measurement of the parts.

[0038] The solution of this invention can quickly and accurately calculate the number of groups in the squirrel cage groove, meet the requirements of the three-coordinate circumferential indexing, and the group-array measurement method can effectively reduce programming difficulty, improve programming efficiency, and realize automatic measurement of batch quantities of parts.

[0039] Example 2:

[0040] 1. A certain part has 80 evenly distributed squirrel cage slots. The minimum circumferential graduation accuracy of the coordinate measuring machine is 7.5°. The coordinate measuring machine is required to detect the position of the 80 squirrel cage slots.

[0041] 2. Calculation of the number of groups: Y / N = X1; (Y: 80, N: number of groups, X1: integer, 1, 2, 3, 4, ...)

[0042] 360° / N = X2 * Z (N: number of groups, X2: integer, 1, 2, 3, 4..., Z: minimum precision of the three-coordinate circumferential division, 7.5°).

[0043] Substituting the values, we get: 80 / N = X1

[0044] 360° / N = X2 * 7.5°

[0045] Assigning values ​​N = 1, 2, 3, 4..., the calculation shows that when N = 16, 80 / 16 = 5, 360° / 16 = 22.5° = 3 * 7.5°, and there are 16 groups in total, with 5 mouse cages in each group;

[0046] 3. Develop an automatic coordinate measuring machine (CMM) program;

[0047] 1) Collect benchmark elements: one surface, one circle, and one angular direction, and establish coordinate system 1;

[0048] 2) Alt+Z to switch to automatic mode, add moving points, and prevent probe collisions;

[0049] 3) Collect the reference elements again: one surface, one circle, and one angular direction. Establish coordinate system 2, rotate the three coordinates by an angle of A-90°B0, and use measurement point 3 as the angular direction. (See attached...) Figure 1 As shown.

[0050] 4) As per the appendix Figure 1 As shown, under state A-90B0, the point acquisition of 5 mouse cage slots in group 1 was completed, and the midpoints of the 5 mouse cage slots, points 3, 6, 9, 12, and 15, were calculated. Then, this group of mouse cage slots was arrayed into 16 groups, with the A-axis rotation angle remaining constant at -90°. The circumferential angles of the B-axis for each group were obtained as follows: 0°, 22.5°, 45°, 67.5°, 90°, 112.5°, 135°, 157.5°, 180°, 202.5°, 225°, 247.5°, 270°, 292.5°, 315°, and 337.5°, all of which are multiples of 7.5°. The actual programming is shown in the appendix. Figure 2 ;

[0051] 5) After the measurement program is compiled, it will run automatically to evaluate the position of the rat cage and display the test results.

[0052] 4. Actual inspection results of parts: The processing method of this invention can quickly and accurately calculate the number of groups of the squirrel cage slots, match the corresponding coordinate measuring machine, solidify the measurement program, realize the batch inspection of the squirrel cage slots, greatly improve the efficiency and accuracy of parts inspection, and reduce the difficulty and intensity of operation.

Claims

1. A method for three-coordinate detection of a squirrel cage slot, characterized in that: The minimum common multiple of the standard interval of the squirrel cage slot and the minimum accuracy of the three-coordinate measuring instrument circumferential indexing is calculated, and all the squirrel cage slots are grouped according to the minimum common multiple; Array measurement is performed according to the number of groups, and the specific steps include: A let Y / N=X1, 360° / N=X2*Z, and through the assignment method, a positive integer is substituted into N until X1 and X2 are both integers, at which time N is the number of squirrel cage slots in each group, wherein Y is the total number of squirrel cage slots, and Z is the minimum accuracy of the three-coordinate circumferential indexing; B the squirrel cage slots are evenly divided into N groups, and the squirrel cage slots are placed into the three-coordinate detector to establish a measurement coordinate system; C the midpoint of each squirrel cage slot in the measured group is collected, the points on the edges of each squirrel cage slot on the same height are collected, and the midpoint of the two edge points is calculated; D the squirrel cage slot is rotated, array measurement is performed according to the number of groups N, and it is judged whether all the midpoints meet the positional accuracy requirement.

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