A method for machining irregular castings based on vector projection deviation compensation

Abstract

The present invention relates to an irregular casting processing method based on vector projection deviation compensation, which belongs to the field of mechanical processing and manufacturing. The method comprises the following steps: selecting two mutually perpendicular surfaces A and B from the non-machined surfaces of a part blank; aligning Z and Y direction lines according to surfaces A and B, generating an X direction, and determining the initial position of the part blank in the X direction of the part coordinate system; clamping the part blank according to the lines in the X, Y, and Z directions, and performing rough processing; selecting a non-machined surface C, the normal of which is at an angle β with the X direction; measuring the actual wall thickness of the non-machined surface C of the part after rough processing, and simultaneously determining the theoretical wall thickness of the non-machined surface C on the part model; calculating the positional deviation of the non-machined surface C on the part relative to the non-machined surface C on the model in the X direction, and determining the position of the part blank in the X direction; processing the part after deviation compensation to complete the part processing. The present invention can achieve accurate fitting of the part blank with the three-dimensional model, providing a basic guarantee for qualified processing of the part.

Description

Technical Field

[0001] The invention belongs to the field of mechanical processing and manufacturing, and in particular relates to an irregular casting processing method based on vector projection deviation compensation. Background Art

[0002] The blank is a casting part, and its inner cavity usually has some non-machined surfaces. Such parts need to first align the non-machined surfaces in the X, Y, and Z directions, and mark the machined surfaces to make the blank fit the model, so as to produce qualified parts.

[0003] However, some parts have complex structures, and the vector projection of the non-machined surface of the inner cavity is three-dimensional in space, but there are only two mutually perpendicular surfaces, and no three mutually perpendicular surfaces. Conventional methods cannot be used to align the non-machined surface and draw lines in the X, Y, and Z coordinate directions, and thus the parts cannot be processed. Summary of the Invention

[0004] Technical issues to be solved:

[0005] In order to solve the technical problem that the vector projection of the non-machined surface of the inner cavity is three-dimensional in space, but there are only two directions of non-machined surfaces perpendicular to each other, and the conventional method cannot be used to align the non-machined surface and mark it in the three coordinate directions of X, Y, and Z, and thus the part cannot be processed, the present invention provides an irregular casting processing method based on vector projection deviation compensation. By utilizing the principle of vector projection, the positioning deviation of the part blank is compensated in the third direction, so that the part blank is accurately fitted with the three-dimensional model, providing a basic guarantee for the qualified processing of the part.

[0006] The technical solution of the present invention is: a method for processing irregular castings based on vector projection deviation compensation, characterized by the following specific steps:

[0007] Step 1: Select two mutually perpendicular faces A and B from the non-machined surfaces of the part blank;

[0008] Step 2: Level the non-machined surface A on the part blank, use the normal direction of the surface as the Z direction of the part coordinate system, draw a line in the Z direction, and determine the position of the part blank in the Z direction in the part coordinate system;

[0009] Step 3: Align the Z direction and mark the non-machined surface B on the part blank. Use the normal direction of this surface as the Y axis direction of the part coordinate system and mark the Y direction to determine the position of the blank in the Y direction of the part coordinate system.

[0010] Step 4: Align the Y and Z directions and draw lines, generate the X direction, align a full machining feature in the X direction and draw lines, and determine the initial position of the part blank in the X direction of the part coordinate system;

[0011] Step 5: Clamp the part blank according to the markings in the X, Y, and Z directions and perform rough machining;

[0012] Step 6: Select a non-machined surface C, whose normal direction makes an angle β with the X direction; measure the actual wall thickness of the non-machined surface C of the part after rough machining, and determine the theoretical wall thickness of the non-machined surface C on the part model;

[0013] Step 7: Calculate the positional deviation of the non-machined surface C on the part relative to the non-machined surface C on the model in the X direction based on the actual wall thickness of the non-machined surface C, the theoretical wall thickness, and the angle between the normal direction of the non-machined surface C and the X direction.

[0014] Step 8: Based on the position deviation obtained in step 7, perform deviation compensation, adjust in the X direction so that the non-machined surface C on the part coincides with the non-machined surface C on the model, and determine the position of the part blank in the X direction;

[0015] Step 9: Process the parts after deviation compensation to complete the part processing.

[0016] A further technical solution of the present invention is: in step 2, the non-machined surface A with a larger area is selected for leveling, that is, the area of the non-machined surface A is larger than the area of the non-machined surface B.

[0017] A further technical solution of the present invention is: in step 5, a 2 mm margin is left after rough machining.

[0018] A further technical solution of the present invention is: in step 6, when selecting the non-machined surface C, the smaller the angle between the normal of the non-machined surface C and the X direction, the better, that is, the unit vector projection in the X direction is larger.

[0019] A further technical solution of the present invention is: in step 7, the calculation formula of the position deviation is:

[0020] (δ-δ′) / cosβ

[0021] Among them, δ is the actual wall thickness of the non-machined surface C of the part after rough machining, and δ′ is the theoretical wall thickness of the non-machined surface C on the part model.

[0022] A further technical solution of the present invention is: in step 8, deviation compensation is performed based on the position deviation calculated in step 7, and -(δ-δ′) / cosβ is adjusted in the X direction.

[0023] A further technical solution of the present invention is: in step 9, it is necessary to reasonably arrange the roughing and finishing processes according to actual conditions.

[0024] Beneficial effects

[0025] The beneficial effects of the present invention are as follows: the present invention utilizes the vector projection principle to perform a method of compensating for the positioning deviation of the part blank in the third direction, which can realize the processing of parts in which the vector projection of the non-machined surface of the inner cavity is three-dimensional in space, but there are only two surfaces perpendicular to each other in two directions, but no surfaces perpendicular to each other in three directions; the part blank is accurately fitted with the model, providing a basic guarantee for the qualified processing of the part. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 Schematic diagrams of the structure of an irregular casting blank part in an embodiment, (a) and (b) are schematic diagrams of the structure from two different perspectives respectively.

[0027] Figure 2 It is a schematic diagram of the non-machined surfaces of the part (side A, side B, side C).

[0028] Figure 3 It is a schematic diagram of the Z-axis positioning of the part.

[0029] Figure 4 It is a schematic diagram of the Y-axis positioning of the part.

[0030] Figure 5 It is a schematic diagram of the temporary positioning of the part in X direction.

[0031] Figure 6 This is a schematic diagram of the position relationship between the blank and the C surface of the model after rough processing.

[0032] Figure 7 It is a schematic diagram of the actual wall thickness and theoretical wall thickness of the C surface of the part after rough machining.

[0033] Figure 8 This is a schematic diagram of the compensation for the X-axis positioning deviation of the part.

[0034] Explanation of the accompanying numbers: 1- non-machined surface; 2, 3- fully machined outer circle; 4- non-machined surface C on the model; 5- non-machined surface C on the blank; 6- machined surface; 7- machined surface fitting. DETAILED DESCRIPTION

[0035] The embodiments described below with reference to the accompanying drawings are exemplary and are intended to explain the present invention, but should not be construed as limiting the present invention.

[0036] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like to indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0037] Figure 1 As shown in the figure, the structural diagram of an irregular part to be processed in this embodiment is a casting. The blank of the part has an irregular overall structure, the inner cavity has multiple non-machined surfaces and the vector projection is three-dimensional in space; the part has a complex structure, and there are only two mutually perpendicular surfaces among the non-machined surfaces, but no three mutually perpendicular surfaces, and it cannot be marked and processed by conventional methods.

[0038] The method of the present invention is used to Figure 1 The specific steps for processing the parts shown are:

[0039] The first step is to determine two mutually perpendicular non-machined surfaces A and B in the non-machined surface of the part blank, such as Figure 2 shown.

[0040] The second step is to select a larger non-machined surface A from the non-machined surfaces A and B, level the non-machined surface A, and use the normal direction of the non-machined surface A as the Z direction of the part coordinate system to mark the blank. The blank and the non-machined surface of the model are aligned in the Z direction, and the Z direction is accurately positioned to determine the position of the part blank in the Z direction, such as Figure 3 shown.

[0041] The third step is to level the other non-machined surface B, and use the normal direction of the non-machined surface B as the Y direction of the part coordinate system to mark the blank. The blank and the non-machined surface of the model are aligned in the Y direction, and the Y direction is accurately positioned to determine the position of the part blank in the Y direction. Figure 4 shown.

[0042] The fourth step is to align the Y and Z directions and mark the lines. The X direction is automatically generated. A fully machined outer circle in the X direction is aligned and marked. The position of the part blank in the X direction is temporarily determined. However, due to the casting error of the fully machined outer circle, there is a certain deviation between the non-machined surface C on the blank and the non-machined surface C on the model in the X direction. Figure 5 shown.

[0043] Due to the complex structure of some parts, the vector projection of the non-machined surface of the inner cavity is three-dimensional, but there are only two mutually perpendicular surfaces, not three mutually perpendicular surfaces. Conventional methods cannot be used to align the non-machined surface and mark it in the X, Y, and Z coordinate directions, making it impossible to machine the part. Therefore, we choose a non-machined surface C, whose normal direction has a small angle β with the X direction, that is, its normal unit vector has a large projection in the X direction.

[0044] Step 5: Find the X, Y, and Z lines and clamp the parts for rough machining, leaving a margin of about 2mm. The positional relationship between the blank and the model at the non-machined surface C is as follows: Figure 6 shown.

[0045] In the sixth step, considering the machining allowance, the actual wall thickness δ from the non-machined surface C to the corresponding machined surface is measured, and the theoretical wall thickness δ′ of the non-machined surface C on the model is determined, as follows: Figure 7 The selection of the non-machined surface C is very important. The smaller the angle between its normal and the X direction, the higher the accuracy of the part blank's position in the X direction.

[0046] In the seventh step, the position deviation of the blank relative to the model in the X direction is calculated based on the actual wall thickness δ of the non-machined surface C, the theoretical wall thickness δ′, and the angle β between the normal direction of the non-machined surface C and the X direction. The position deviation is (δ-δ′) / cosβ.

[0047] In the eighth step, the deviation is compensated based on the position deviation calculated in the seventh step. -(δ-δ′) / cosβ is adjusted in the X direction to make the non-machined surface C on the blank coincide with the non-machined surface C on the model. At this point, within the allowable range of casting error, all non-machined surfaces of the blank and the model fit together, that is, the part blank fits the model. Figure 8 As shown; at this time, although the processed surface has position deviation, the processing allowance is large and the part can still be processed qualified later.

[0048] The ninth step is to process the parts after deviation compensation, and reasonably arrange the rough and fine processing procedures according to the actual situation to complete the parts processing.

[0049] Although the embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are illustrative and are not to be construed as limitations on the present invention. A person skilled in the art may change, modify, replace and modify the above embodiments within the scope of the present invention without departing from the principles and purpose of the present invention.

Claims

1. A method for processing irregular castings based on vector projection deviation compensation, characterized in that The specific steps are as follows: Step 1: Select two mutually perpendicular faces A and B from the non-machined surfaces of the part blank; Step 2: Level the non-machined surface A on the part blank, use the normal direction of the surface as the Z direction of the part coordinate system, draw a line in the Z direction, and determine the position of the part blank in the Z direction in the part coordinate system; Step 3: Align the Z direction and mark the non-machined surface B on the part blank. Use the normal direction of this surface as the Y axis direction of the part coordinate system and mark the Y direction to determine the position of the blank in the Y direction of the part coordinate system. Step 4: Align the Y and Z directions and draw lines, generate the X direction, align a full machining feature in the X direction and draw lines, and determine the initial position of the part blank in the X direction of the part coordinate system; Step 5: Clamp the part blank according to the markings in the X, Y, and Z directions and perform rough machining; Step 6: Select a non-machined surface C, whose normal direction makes an angle β with the X direction; measure the actual wall thickness of the non-machined surface C of the part after rough machining, and determine the theoretical wall thickness of the non-machined surface C on the part model; Step 7: Calculate the positional deviation of the non-machined surface C on the part relative to the non-machined surface C on the model in the X direction based on the actual wall thickness of the non-machined surface C, the theoretical wall thickness, and the angle between the normal direction of the non-machined surface C and the X direction. Step 8: Based on the position deviation obtained in step 7, perform deviation compensation, adjust in the X direction so that the non-machined surface C on the part coincides with the non-machined surface C on the model, and determine the position of the part blank in the X direction; Step 9: Process the parts after deviation compensation to complete the part processing.

2. The irregular casting processing method based on vector projection deviation compensation according to claim 1, characterized in that: In step 2, the non-machined surface A with a larger area is selected for leveling, that is, the area of the non-machined surface A is larger than the area of the non-machined surface B.

3. The irregular casting processing method based on vector projection deviation compensation according to claim 1, characterized in that: In step 5, a 2 mm margin is left after rough machining.

4. The irregular casting processing method based on vector projection deviation compensation according to claim 1, characterized in that: In step 6, when the non-machined surface C is selected, the smaller the angle between the normal of the non-machined surface C and the X direction, the better, that is, the unit vector projection in the X direction is larger.

5. The irregular casting processing method based on vector projection deviation compensation according to claim 1, characterized in that: In step 7, the calculation formula of the position deviation is: (δ-δ′) / cosβ Among them, δ is the actual wall thickness of the non-machined surface C of the part after rough machining, and δ′ is the theoretical wall thickness of the non-machined surface C on the part model.

6. The irregular casting processing method based on vector projection deviation compensation according to claim 5, characterized in that: In step 8, deviation compensation is performed based on the position deviation calculated in step 7, and -(δ-δ') / cosβ is adjusted in the X direction.

7. The irregular casting processing method based on vector projection deviation compensation according to claim 1, characterized in that: In step 9, it is necessary to reasonably arrange the roughing and finishing processes according to the actual situation.

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