Machining allowance detection method and machining method of shell casting blank

Abstract

The invention provides a machining allowance detection method and a machining method of a shell casting blank. Three-dimensional scanning equipment is used for conducting scanning when the shell casting blank is placed forwards, reversely and laterally; carrying out the optimal fitting of the scanning parts which are placed uprightly, uprightly and laterally, and generating a final scanning part; pre-aligning the final scanning part and the shell model to obtain the margins of the machining surface and the non-machining surface in the shell casting blank; drawing up a rough reference according to the importance of a non-machined surface and the margin uniformity degree; and performing optimal fitting on the final scanning part and the shell model, determining the stability of the allowance of the rough reference surface and the maximum machining allowance through allowance analysis, and determining the rough reference according to the stability of the allowance of the rough reference surface. The invention provides a shell casting blank machining allowance detection method and a machining method, which are used for overcoming the defects of low efficiency and poor repeatability of existing manual lineation and realizing non-lineation machining of castings.

Description

Technical Field

[0001] The present invention relates to the technical field of structural part processing, and particularly to a method for detecting machining allowance and a machining method for a rough casting of a housing. Background Art

[0002] Housing parts are common types in aerospace products. Among the machining blanks of existing structural parts, casting blanks account for a large proportion. Due to different production batches, the machining allowance of each batch of blanks is inconsistent for casting manufacturers. After the castings arrive, manual marking is first carried out. When marking, the non-machining plane of the casting itself is referred to to determine the machining allowance. After marking, the rough machining stage uses an ordinary milling machine to complete the machining of the six rough reference surfaces. Manual marking requires special equipment such as a marking platform for assistance, which requires high labor costs, low efficiency, and poor repeatability. The subsequent rough milling and line-finding mode also has the same problems of low efficiency and poor accuracy. Summary of the Invention

[0003] The present invention provides a method for detecting machining allowance and a machining method for a rough casting of a housing, which are used to overcome the disadvantages of low efficiency and poor repeatability of existing manual marking and realize non-marking machining of castings.

[0004] On the one hand, the present invention provides a method for detecting machining allowance of a rough casting of a housing, including:

[0005] Using a three-dimensional scanning device to scan the rough casting of the housing respectively when it is placed upright, upside down, and sideways, and storing them as scanned components for upright, upside down, and sideways placement respectively. The sideways placement can be based on any side of the rough casting of the housing;

[0006] Performing optimal fitting on the scanned components for upright, upside down, and sideways placement to generate a final scanned component;

[0007] Pre-aligning the final scanned component and the housing model to obtain the allowances of the machining surface and the non-machining surface in the rough casting of the housing;

[0008] Formulating rough references according to the importance and allowance uniformity of the non-machining surface. The formulation of rough references includes formulating three mutually perpendicular non-machining surfaces as rough reference surfaces. The first rough reference surface restricts three degrees of freedom, the second rough reference surface restricts two degrees of freedom, and the third rough reference surface restricts one degree of freedom;

[0009] Performing optimal fitting on the final scanned component and the housing model, determining the stability and maximum machining allowance of the rough reference surface allowance through allowance analysis, and determining the rough reference according to the stability of the rough reference surface allowance.

[0010] Optionally, it further includes:

[0011] Before scanning, calibrating and calibrating the three-dimensional scanning device;

[0012] Use the three-dimensional scanning device to scan the turntable and paste the first positioning point marks on the turntable;

[0013] Paste the second positioning point marks on the rough blank of the housing casting.

[0014] Optionally, the pasting of the second positioning point marks on the rough blank of the housing casting includes:

[0015] Paste the second positioning point marks on the surfaces with clear vision when the rough blank of the housing casting is placed upright, upside down, and sideways, and the number of the second positioning point marks pasted on each surface is greater than or equal to 4.

[0016] Optionally, determining the stability of the rough reference surface allowance includes determining whether the rough reference surface allowance is within the stable range.

[0017] On the other hand, the present invention provides a processing method for the rough blank of the housing casting. According to the rough reference and the maximum machining allowance determined by any of the above methods, it includes:

[0018] Complete the rough machining clamping on the combined fixture pre-designed according to the rough reference, use UG to compile the numerical control program according to the maximum machining allowance, and complete the rough machining of the rough blank of the housing casting;

[0019] Clamp with the machined surface after rough machining as the positioning reference to complete the semi-finishing machining of the rough blank of the housing casting;

[0020] Complete the finish machining of the rough blank of the housing casting according to the design reference.

[0021] Optionally, the combined fixture pre-designed according to the rough reference includes a base plate, four support columns, a support plate, and two clamping mechanisms, where:

[0022] The base plate is used to install the support columns, and a plurality of strip grooves are respectively arranged on the base plate in the transverse and longitudinal directions;

[0023] One or more side surfaces of the support columns are provided with strip grooves from top to bottom. The support columns are installed with first connecting pieces from the bottom surface. After the support columns move along the strip grooves on the base plate to the selected positions, the first connecting pieces fix the support columns on the base plate. The support columns are divided into three high support columns and one short support column. The three high support columns are used to position the first rough reference surface and have the same height. Two of the high support columns are also used to position the second rough reference surface, and the short support column is used to fix the support plate;

[0024] The support plate is used to position the third rough reference surface. A second connecting member is installed on the side surface of the support plate. After the support plate moves along the slot on the short support column to a selected position, the second connecting member fixes the support plate on the short support column.

[0025] The two clamping mechanisms are used to clamp the rough housing casting. The two clamping mechanisms are respectively connected to the symmetric two sides of the base plate and can move along the directions away from and close to the base plate.

[0026] Optionally, the sizes of the base plate, the support columns, the support plate and the clamping mechanisms can be adjusted according to the size of the rough housing casting.

[0027] Optionally, the slots on the base plate and the support columns are T-shaped slots. Through holes penetrating the column body are provided on the support columns, and through holes penetrating the side surfaces are provided on the support plate. Both the first connecting member and the second connecting member include bolts and nuts for T-shaped slots.

[0028] Optionally, the rough machining clamping completed on the combined fixture pre-designed according to the rough reference includes:

[0029] Move the two clamping mechanisms in the directions away from the base plate respectively until enough space is reserved for positioning the rough housing casting.

[0030] Install the support columns on the base plate and position the rough housing casting so that the top surfaces of the three high support columns all contact the first rough reference surface, and any one side surface of two of the high support columns contacts the second rough reference surface. Fix the support plate through the short support column and make the side surface of the support plate facing the short support column contact the third rough reference surface.

[0031] After positioning the rough housing casting, move the two clamping mechanisms in the directions close to the base plate respectively until the rough housing casting is clamped.

[0032] Optionally, the height of the support plate is such that the margin of the third rough reference surface at this height is relatively small and the clamping of the rough housing casting is relatively stable.

[0033] Compared with the prior art, the present invention has the following beneficial effects:

[0034] Through non-contact detection, digital detection of machining allowance is realized.

[0035] Through the reference correction and precision matching between the digital scanning component and the housing model, allowance transfer is realized.

[0036] Combined with the designed modular fixture, non-scratch machining of the roughcast of the housing casting from rough machining to finish machining on a five-axis device is achieved. Description of the Drawings

[0037] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for description in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0038] Figure 1 It is a schematic flow chart of a method for detecting machining allowance of a roughcast of a housing casting provided in Embodiment 1 of the present invention;

[0039] Figure 2 It is a schematic diagram of the housing structure provided in Embodiment 1 of the present invention;

[0040] Figure 3 It is a schematic flow chart of a method for machining a roughcast of a housing casting provided in Embodiment 2 of the present invention.

[0041] Figure 4 It is a schematic diagram of the structure of the modular fixture provided in Embodiment 2 of the present invention except for the clamping mechanism. Detailed Embodiments

[0042] The present invention will be further described in detail below in conjunction with the drawings. Obviously, the described embodiments are only some embodiments of the present invention, rather than all embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts belong to the scope of protection of the present invention.

[0043] Embodiment 1:

[0044] This embodiment provides a method for detecting machining allowance of a roughcast of a housing casting. As Figure 1 shown, the method in this embodiment is implemented based on GOM software and includes:

[0045] S10: Use a three-dimensional scanning device to scan the roughcast of the housing casting respectively when it is placed upright, upside down, and sideways, and store them as scanned components in the upright, upside-down, and sideways positions respectively. The sideways position can be based on any side of the roughcast of the housing casting.

[0046] Before scanning, the following preparations need to be made:

[0047] Calibrate and align a three-dimensional scanning device, including detecting the resolution of the measuring head of the three-dimensional scanning device, adjusting the position, height, and angle of the three-dimensional scanning device with reference to GOM software so that the purple image measured by the measuring head is completely within the area of the calibration plate image, and ensuring that all non-machined surfaces can be measured when the rough casting of the housing is placed upright;

[0048] Use the three-dimensional scanning device to scan the turntable and paste the first positioning point label on the turntable. The first positioning point label on the turntable is used as the shear plane during non-contact scanning. The turntable can be a reference turntable or a rotating turntable;

[0049] Paste the second positioning point label on the rough casting of the housing, including pasting the second positioning point label on the surfaces that still have a clear view when the rough casting of the housing is placed upright, upside down, and on its side. The number of second positioning point labels pasted on each surface is greater than or equal to 4. The second positioning point label can improve the accuracy of the scanning results. Try to paste all the second positioning point labels at one time before scanning. If it is found during the scanning process that the scanned surface of some structures is incomplete, the second positioning point label can also be supplemented and pasted during the scanning process.

[0050] At the same placement position, except for the surface in contact with the turntable that cannot be scanned, all other surfaces of the rough casting of the housing can be scanned. The point cloud data obtained by scanning is the scanned part.

[0051] In this embodiment, the three-dimensional scanning device used is Hawk, and the housing structure is as Figure 2 shown, including the top surface 1, the front side surface 2, the rear side surface, the left side surface, the right side surface 3, the bottom surface, the inner cavity front side surface, the inner cavity rear side surface 4, the inner cavity left side surface 5, the inner cavity right side surface, the inner cavity bottom surface 6, the inner cavity left edge 7, the left groove edge 8, the left circular boss 9, the slot wall surface 10, the inner cavity right edge 11, and the right circular boss 12, where: the rear side surface is on the reverse side of the inner cavity rear side surface 4, the left side surface is on the reverse side of the inner cavity left side surface 5, the bottom surface is on the reverse side of the inner cavity bottom surface 6, the inner cavity front side surface is on the reverse side of the front side surface 2, the inner cavity right side surface is on the reverse side of the right side surface 3, the inner cavity rear side surface 4 includes the slot wall surface 10, and the right groove edge is directly opposite to the left groove edge 8. When the top surface 1 is placed upward, it is placed upright. When the bottom surface is placed upward, it is placed upside down. When any side surface is placed downward, it is placed on its side. The second positioning point label is pasted on the side surface of the inner cavity of the housing, and it can also be pasted on the side surface outside the housing.

[0052] S11: Optimally fit the scanned parts placed upright, upside down, and on their sides to generate the final scanned part.

[0053] The optimal fit is a function built into the GOM software.

[0054] S12: Pre-align the final scanned part and the housing model to obtain the allowances of the machined and non-machined surfaces in the rough casting of the housing.

[0055] Pre-alignment is a function built into the GOM software. In this embodiment, the machined surfaces include the top surface 1, the front side surface 2, the rear side surface, the left side surface, the right side surface 3, the bottom surface, the left circular boss 9, the slot wall surface 10, and the right circular boss 12, and the non-machined surfaces include the inner cavity front side surface, the inner cavity rear side surface 4, the inner cavity left side surface 5, the inner cavity right side surface, the inner cavity bottom surface 6, the inner cavity left edge 7, the left slot edge 8, the right slot edge, and the inner cavity right edge 11.

[0056] S13: Determine the rough datum according to the importance and evenness of the allowance of the non-machined surface. Determining the rough datum includes determining three mutually perpendicular non-machined surfaces as the rough datum surfaces. The first rough datum surface restricts three degrees of freedom, the second rough datum surface restricts two degrees of freedom, and the third rough datum surface restricts one degree of freedom.

[0057] In this embodiment, according to the importance of the non-machined surface, determine three mutually perpendicular non-machined surfaces where the inner cavity bottom surface 6, the inner cavity edges, and the slot edges are located as the rough datum surfaces. The inner cavity edges include the inner cavity left edge 7 and the inner cavity right edge 11, which are in the same plane and do not need to be selected. The slot edges include the left slot edge 8 and the right slot edge, and the two are not in the same plane. Since the allowance distribution of the right slot edge is more uniform in this embodiment, the right slot edge is selected as the rough datum surface. Six degrees of freedom are restricted for the rough datum surface based on the 3-2-1 principle. The inner cavity bottom surface 6 is used as the first rough datum surface to restrict three degrees of freedom, the inner cavity edge is used as the second rough datum surface to restrict two degrees of freedom, and the right slot edge is used as the third rough datum surface to restrict one degree of freedom.

[0058] S14: Perform the best fit on the final scanned part and the shell model, determine the stability and the maximum machining allowance of the rough datum surface allowance through allowance analysis, and determine the rough datum according to the stability of the rough datum surface allowance.

[0059] Use the point-by-point detection function of the GOM software to perform allowance analysis to determine the stability and the maximum machining allowance of the rough datum surface allowance. Through the datum correction and accuracy matching of the scanned part and the shell model, the allowance transfer is realized, that is, the allowance is transferred from the shell casting blank to the scanned part, and then the maximum machining allowance is transferred back from the final scanned part to the shell casting blank. The maximum machining allowance is used to machine the machined surfaces of the shell casting blank.

[0060] Determining the stability of the rough datum surface allowance means determining whether the allowances of the rough datum surfaces are all within the stable range. If they are within the stable range, the rough datum can be determined. If it exceeds the range, it means that the dimensional allowance of the non-machined surface is insufficient, indicating that the shell casting blanks of this batch are not usable. If the allowance of the slot edge is seriously insufficient, it will cause the slot to be unable to place assembly parts such as circuit boards. In this embodiment, the stable range is less than or equal to 0.05 mm.

[0061] Embodiment 2:

[0062] This embodiment provides a processing method for a housing casting blank. According to the rough datum and the maximum machining allowance determined by the method in Embodiment 1, as Figure 3 shown, it includes:

[0063] S20: Complete the rough machining clamping on the combined fixture pre-designed according to the rough datum. Use UG to compile a numerical control program according to the maximum machining allowance to complete the rough machining of the housing casting blank.

[0064] The combined fixture pre-designed according to the rough datum includes a base plate (precision positioning base plate), four support columns (vertical groove square supports), a support plate, and two clamping mechanisms. Figure 4 shows the structure of the combined fixture except for the clamping mechanism, where:

[0065] The base plate 13 is used to install the support columns. Multiple strip grooves are respectively arranged on the base plate 13 in the transverse and longitudinal directions. In this embodiment, the strip grooves are T-shaped grooves.

[0066] One or more sides of the support column 14 are provided with strip grooves from top to bottom. In this embodiment, all four sides of the support column 14 are provided with T-shaped grooves from top to bottom. The support column 14 is installed with a first connecting piece from the bottom surface. After the support column 14 moves along the strip grooves on the base plate 13 to the selected position, the first connecting piece fixes the support column 14 on the base plate 13. The support column 14 is divided into three high support columns and one short support column. The three high support columns are used to locate the first rough datum surface and have the same height. Among them, two high support columns are also used to locate the second rough datum surface. The short support plate is used to fix the support plate. In one implementation manner, a through hole 16 penetrating the column body is provided on the support column 14. The first connecting piece is a T-shaped groove bolt (rectangular head groove bolt) and a nut. The T-shaped groove bolt is inserted from the through hole opening at the bottom of the support column 14 and passes through the through hole opening at the top of the support column 14, and is finally fixed by the nut. In another implementation manner, a through hole 16 penetrating the column body is provided on the support column 14. Internal threads are provided in the through hole 16. The first connecting piece is a T-shaped groove bolt. The T-shaped groove bolt is screwed into from the through hole opening at the bottom of the support column 14 and is screwed out and fixed from the through hole opening at the top of the support column 14.

[0067] The support plate 15 is used to locate the third rough datum surface. A second connecting piece is installed on the side surface of the support plate 15. After the support plate 15 moves along the strip grooves on the short support column to the selected position, the second connecting piece fixes the support plate 15 on the short support column. In this embodiment, through holes penetrating the side surface are provided on the support plate 15. The second connecting piece includes a T-shaped groove bolt and a nut 17. The T-shaped groove bolt is inserted from one side through hole opening and passes through the through hole opening on the other side, and is finally fixed by the nut 17.

[0068] Two clamping mechanisms are used to clamp the rough casting of the housing. The two clamping mechanisms are respectively connected to the symmetric two sides of the base plate 13. According to the actual situation of the rough casting of the housing, they can be respectively connected to the front and rear sides or the left and right sides. The two clamping mechanisms can move in the directions away from and close to the base plate 13, and the clamping mechanisms can be realized by using common clamping mechanisms.

[0069] The dimensions of the base plate 13, the supporting columns 14, the supporting plate 3 and the clamping mechanisms can be adjusted according to the dimensions of the rough casting of the housing.

[0070] The rough machining clamping on the combined fixture pre-designed according to the rough datum includes:

[0071] Move the two clamping mechanisms in the directions away from the base plate 13 respectively until enough space is reserved for positioning the rough casting of the housing.

[0072] Install the supporting columns on the base plate to position the rough casting of the housing, so that the top surfaces of the three high supporting columns all contact the first rough datum surface to realize the constraint of three degrees of freedom of the first rough datum surface. Any one of the side surfaces of the two high supporting columns contacts the second rough datum surface to realize the constraint of two degrees of freedom of the second rough datum surface. Fix the supporting plate 15 through the short supporting column and make the side surface of the supporting plate 15 facing the short supporting column contact the third rough datum surface to realize the constraint of one degree of freedom of the third rough datum surface.

[0073] After positioning the rough casting of the housing, move the two clamping mechanisms in the directions close to the base plate 13 respectively until the rough casting of the housing is clamped.

[0074] The height of the supporting plate 15 needs to make the allowance in height of the third rough datum surface relatively small and make the clamping of the rough casting of the housing relatively stable.

[0075] In this embodiment, the rough casting of the housing is placed upside down on the base plate 13 with the supporting columns and the supporting plate installed, so that the top surfaces of the three high supporting columns all contact the inner cavity bottom surface 6. Any one of the side surfaces of the two high supporting columns respectively contacts the inner cavity right edge 11 and the inner cavity left edge 7. Fix the supporting plate 15 through the short supporting column and make the side surface of the supporting plate 15 facing the short supporting column contact the right groove edge.

[0076] In this embodiment, the height of the rough casting of the housing is about 200 mm. The rough machining only involves the top surface 1 of the rough casting of the housing and the areas of the four outer side surfaces starting from the top surface 1 and having a certain height downward. Based on the structural characteristics of the housing, the certain height is based on the height that can ensure the cutting effect of the tool. In this embodiment, the certain height is 20 mm.

[0077] S21: Clamp with the machined surface after rough machining as the positioning datum to complete the semi-finishing machining of the rough casting of the housing.

[0078] In this embodiment, the machining of the remaining areas of the four outer sides, the bottom surface, the left circular boss 9, the slot wall surface 10, and the right circular boss 12 of the shell rough blank belongs to semi-finishing machining, and the semi-finishing machining is realized based on common clamping methods.

[0079] S22: Finish machining the shell casting rough blank according to the design datum.

[0080] The design datum is the datum designed according to the assembly and use requirements, and the finish machining is realized based on common clamping methods.

[0081] The shell casting rough blank is machined from rough machining to finish machining on a five-axis device, and the shell casting rough blanks of the same batch can be batch-machined according to the method in Embodiment 2 with the same settings.

[0082] Although the preferred embodiments of the present invention have been described, those skilled in the art can make additional changes and modifications to these embodiments once they know the basic creative concept. Therefore, the appended claims are intended to be construed to include the preferred embodiments as well as all changes and modifications falling within the scope of the present invention.

[0083] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalent technologies, the present invention also intends to include these modifications and variations.

Claims

1. A method for detecting machining allowance of a rough casting of a housing, characterized in that, Including: Using a three-dimensional scanning device to scan the rough casting of the housing when it is placed upright, upside down, and sideways respectively, and storing them as scanned components for upright, upside down, and sideways placement respectively. The sideways placement can be based on any side of the rough casting of the housing. Performing optimal fitting on the scanned components for upright, upside down, and sideways placement to generate a final scanned component. Pre-aligning the final scanned component and the housing model to obtain the allowances of the machined surface and non-machined surface in the rough casting of the housing. Determining a rough datum according to the importance of the non-machined surface and the evenness of the allowance. The determination of the rough datum includes determining three mutually perpendicular non-machined surfaces as rough datum surfaces. The first rough datum surface restricts three degrees of freedom, the second rough datum surface restricts two degrees of freedom, and the third rough datum surface restricts one degree of freedom. Performing optimal fitting on the final scanned component and the housing model, determining the stability of the allowance of the rough datum surface and the maximum machining allowance through allowance analysis, and determining the rough datum according to the stability of the allowance of the rough datum surface.

2. The method according to claim 1, wherein Also including: Before scanning, calibrating and adjusting the three-dimensional scanning device. Using the three-dimensional scanning device to scan a turntable and pasting a first positioning point mark on the turntable. Pasting a second positioning point mark on the rough casting of the housing.

3. The method according to claim 2, wherein The pasting of the second positioning point mark on the rough casting of the housing includes: Pasting the second positioning point mark on the surfaces with clear vision when the rough casting of the housing is placed upright, upside down, and sideways. The number of the second positioning point marks pasted on each surface is greater than or equal to 4.

4. The method according to claim 1, wherein The determination of the stability of the allowance of the rough datum surface includes determining whether the allowances of the rough datum surfaces are all within the stable range.

5. A processing method for a rough blank of a housing casting, according to the rough reference and the maximum machining allowance determined by the method according to any one of claims 1-4, characterized in that, Including: Completing the rough machining clamping on a combined fixture pre-designed according to the rough datum, using UG to compile a numerical control program according to the maximum machining allowance, and completing the rough machining of the rough casting of the housing. Clamping with the machined surface after rough machining as the positioning datum to complete the semi-finishing machining of the rough casting of the housing. Completing the finishing machining of the rough casting of the housing according to the design datum.

6. The method according to claim 5, characterized in that, The combined fixture pre-designed according to the rough datum includes a base plate, four support columns, a support plate, and two clamping mechanisms, where: The base plate is used to install the support columns, and multiple strip grooves are respectively arranged on the base plate in the transverse and longitudinal directions. One or more sides of the support columns are provided with strip grooves from top to bottom. The support columns are installed with first connecting pieces from the bottom. After the support columns move along the strip grooves on the base plate to the selected positions, the first connecting pieces fix the support columns on the base plate. The support columns are divided into three high support columns and one short support column. The three high support columns are used to position the first rough datum surface and have the same height. Two of the high support columns are also used to position the second rough datum surface. The short support column is used to fix the support plate. The support plate is used to position the third rough datum surface. The side of the support plate is installed with a second connecting piece. After the support plate moves along the strip grooves on the short support column to the selected position, the second connecting piece fixes the support plate on the short support column. The two clamping mechanisms are used to clamp the roughcast of the housing casting. The two clamping mechanisms are respectively connected to the two symmetrical sides of the base plate and can move in directions away from and towards the base plate.

7. The method according to claim 6, characterized in that, The dimensions of the base plate, the support columns, the support plate and the clamping mechanisms can be adjusted according to the dimensions of the roughcast of the housing casting.

8. The method according to claim 6, wherein The strip grooves on the base plate and the support columns are T-shaped grooves. Through holes penetrating the column bodies are provided on the support columns, and through holes penetrating the sides are provided on the support plate. The first connecting piece and the second connecting piece both include bolts and nuts for T-shaped grooves.

9. The method according to claim 6, wherein The rough machining clamping completed on the combined fixture pre-designed according to the rough datum includes: Moving the two clamping mechanisms in directions away from the base plate respectively until enough space is reserved for positioning the roughcast of the housing casting; Installing the support columns on the base plate, positioning the roughcast of the housing casting so that the top surfaces of the three high support columns all contact the first rough datum surface, and any one side surface of two of the high support columns contacts the second rough datum surface. Fixing the support plate with the short support column and making the side surface of the support plate facing the short support column contact the third rough datum surface; After positioning the roughcast of the housing casting, moving the two clamping mechanisms in directions towards the base plate respectively until the roughcast of the housing casting is clamped.

10. The method according to claim 9, wherein The height of the support plate needs to make the allowance of the third rough datum surface at this height relatively small and make the clamping of the roughcast of the housing casting relatively stable.

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