A processing method suitable for a new energy automobile electric control box shell

Abstract

This invention discloses a processing method suitable for the housing of electronic control boxes in new energy vehicles. The original two processes are broken down into four, with a scientific and rational allocation of processing content, resulting in a more balanced processing cycle. The cycle time of the bottleneck process is reduced by 45% compared to traditional solutions, and the overall line balance rate is increased from 80.3% to 96.6%. This invention reduces data instability caused by deformation of the blank surface and side positioning reference surface, using stable machined holes and surfaces for positioning processing, improving the stability of key dimensional data by 80%.

Description

Technical Field

[0001] This invention belongs to the field of die-cast aluminum alloy machining technology, and mainly relates to a machining method suitable for the housing of electrical control box in new energy vehicles. Background Technology

[0002] All performance indicators of new energy vehicles require unified coordination and execution through electronic control. Electronic control systems are composed of various integrated circuit components, which are generally quite fragile and expensive, requiring a very robust casing for protection. These components are typically made of die-cast aluminum alloy, a thin-walled material. Traditional machining of this alloy involves complex processes, often requiring not only front-side machining but also side and hole machining, resulting in low processing efficiency, unbalanced processing cycles, unstable product flatness, and inconsistent processing data.

[0003] The shortcomings of existing processing methods for the housing of electrical control boxes in new energy vehicles:

[0004] 1. The original plan uses two processing steps. Step 1 processes the upper cover assembly face system, connector face system, and B+ connector face system. Step 2 processes the lower cover assembly face system, water channel face system, pressure heater mounting and positioning surface, and M8 threaded hole face system. The processing cycle of each step in this plan is unbalanced, the overall line balance rate is low, and the stability of key dimensional data is poor.

[0005] 2. The original plan used the blank reference surface for positioning and completed the rough and fine machining of the upper cover plate assembly surface in the same process. However, due to the instability of the flatness of the blank reference surface and the side positioning reference, and the inability to release the internal stress after the product is processed, the flatness of the upper cover plate assembly surface, the lower cover plate assembly surface and the water channel surface is unstable, resulting in unstable hole position dimension data measured with the reference of the three surfaces. Summary of the Invention

[0006] The purpose of this invention is to solve the above problems and provide a processing method suitable for the housing of the electric control box of new energy vehicles.

[0007] The objective of this invention is achieved through the following technical solution:

[0008] A processing method for the housing of an electrical control box in new energy vehicles includes the following steps:

[0009] A. Mount the blank of the electrical control box housing to be processed onto the machining fixture, and use the three blank positioning reference surfaces and three blank positioning surfaces defined in the drawing for positioning:

[0010] a. Use a milling cutter with a diameter of φ50mm to rough mill the assembly surface of the upper cover plate, leaving a 0.2mm allowance for finishing. The rough-milled assembly surface of the upper cover plate is the process positioning surface of steps B and C.

[0011] b. Use a PCD step drill reamer to finish machine 18 bolt mounting holes, with the hole diameter controlled at 17*φ7.8mm±0.1mm and 1*φ6.5mm±0.1mm.

[0012] c. Use a step drill and a reamer to machine the four support pin mounting holes on the assembly surface of the top cover plate, with the hole diameter controlled at φ8mm±0.018mm.

[0013] d. Use a φ8mm diameter corrugated end mill and a φ8mm diameter coated end mill to machine the insulating sheet surface, requiring a surface flatness of 0.1mm;

[0014] e. Use a milling cutter bar with a diameter of φ25mm to machine the end faces of the three connector holes and the end faces of the four M6 threaded holes, requiring a flatness of 0.1mm.

[0015] f. Use a φ8mm forming milling cutter and a φ8mm chamfering cutter to machine three connector holes, requiring a full circumferential width of 0.2mm.

[0016] g. Use a step drill to machine the M5 self-tapping screw holes for installing the connector, with an inner diameter of 16*φ4.64mm±0.1mm;

[0017] h. Use a step drill to machine the positioning holes for installing the connector, with the inner diameters controlled as follows: 2*φ3.5mm±0.1mm and 1*φ3.7mm±0.1mm.

[0018] i. Use a step drill and tap to machine four M6 threaded holes. The thread requirement is M6X1.0-6H.

[0019] B. Position and clamp the two bolt mounting holes and the upper cover plate assembly surface machined in step A, and then rough machine the lower cover plate assembly surface and related hole system:

[0020] a. Roughly machine the lower cover plate assembly surface and two water passage surfaces using a φ32mm diameter milling cutter, leaving a 0.2mm allowance for finishing;

[0021] b. Use a step drill and tap to machine 33 M5 threaded holes for installing the cooling cover plate. The thread requirement is M5X0.8-6H.

[0022] c. Use a φ16mm diameter end mill to machine the mounting end faces of 18 bolt mounting holes and the end faces of 10 inverter grid assembly M4 self-tapping screw holes, requiring a face wheel width of 0.4mm;

[0023] d. Use a φ20mm end mill to machine the end face of one M8 threaded hole one, one M8 threaded hole two, three M6 threaded holes three, six M6 threaded holes four, as well as the end face of two pre-installation positioning holes one and one pre-installation positioning hole two. The surface distance tolerance is required to be ±0.3mm.

[0024] e. Use a step drill and tap to machine one M8 threaded hole one, and use a step drill and tap to machine one M8 threaded hole two. The thread requirement is M8X1.25-6H.

[0025] f. Use a step drill and tap to machine three M6 threaded holes. Use a step drill and tap to machine six M6 threaded holes. The thread requirement is M6X1-6H.

[0026] g. Use a step drill to machine two pre-installation positioning holes (2 x φ10mm) and one pre-installation positioning hole (2 x φ10mm), with a diameter requirement of φ10mm ± 0.2mm.

[0027] C. Position and clamp the two bolt mounting holes and the upper cover plate assembly surface processed in step A, and then finish machine the lower cover plate assembly surface and related hole system:

[0028] a. Use a milling cutter with a diameter of φ50mm to finish machine the assembly surface of the lower cover plate, and use a polishing brush to remove the burrs that are easy to fall off the edges. The surface roughness requirement is Ra1.0mm~5.0mm, and the surface flatness requirement is 0.2mm.

[0029] b. Use a milling cutter with a diameter of φ32mm to finish machine the waterway surface, with a surface roughness requirement of Ra1.0mm~5.0mm;

[0030] c. Use a PCD step drill and reamer to machine 23 M5 self-tapping screw holes on the mounting surface of the lower cover plate, with a thread requirement of φ4.64mm±0.1mm;

[0031] d. Use a step drill and reamer to rough and finish machine two positioning and mounting holes for the lower cover plate, with a diameter requirement of φ4mm±0.1mm;

[0032] e. Use a PCD tooling tool to machine two cooling cover plate mounting positioning pins with a diameter requirement of φ6mm±0.05mm;

[0033] f. Use a PCD tooling tool to machine 7 inverter grid assembly mounting and positioning pins with a diameter requirement of φ4mm±0.1mm;

[0034] g. Use a twist drill and chamfering tool to machine 10 M4 self-tapping screw holes for the inverter grid assembly, with a diameter requirement of φ3.68mm±0.1mm;

[0035] h. Use a φ16mm diameter end mill to machine the mounting end face of the dust plug sealing hole, requiring a face wheel width of 0.4mm;

[0036] i. Use a step drill and tap to machine an M6 threaded hole, the thread requirement is M6X1.0-6H;

[0037] j. Use a step drill, reamer, and broach to machine the sealing hole of the dust plug, with a diameter requirement of φ8.2mm±0.1mm;

[0038] k. Use a milling cutter with a diameter of φ32mm to machine the end face of the B+ connector hole, requiring a surface distance tolerance of ±0.3mm;

[0039] 1. Use a roughing and finishing integrated drill and reamer to machine the B+ connector hole, with a diameter requirement of φ36.3mm±0.03mm;

[0040] n. Use a twist drill to machine two M4 self-tapping screw holes for installing B+ connectors, with a diameter requirement of φ3.68mm±0.08mm;

[0041] m. Use a drill and milling cutter to machine the limiting hole for installing the B+ connector. The diameter requirement is φ3.2mm±0.08mm, and the positional accuracy requirement is 0.2mm.

[0042] D. Using the two lower cover plate positioning and mounting holes and the lower cover plate assembly surface machined in step C, finish machining the upper cover plate assembly surface and multiple holes:

[0043] a. Use a φ50mm diameter cutter head to precision machine the upper cover plate assembly surface, and use a polishing brush to remove burrs that are easy to fall off the edges. The surface roughness requirement for the upper cover plate assembly surface is Ra max16, and the surface flatness requirement is 0.15mm.

[0044] b. Use a step drill and reamer to rough and finish machine two positioning reference holes for the upper cover plate. The diameter requirement is φ10.1mm±0.05mm, and the positional accuracy requirement is 0.2.

[0045] c. Use a PCD tooling tool to machine 30 positioning pins for the hands and 3 positioning pins for the circuit components. The positional accuracy requirement is 0.2, and the hole diameter requirement is φ4mm±0.05.

[0046] d. Use an 8mm diameter end mill to machine the mounting faces of all circuit components and the three waist-shaped locating pins, requiring a contour accuracy of 0.4mm and a position accuracy of 0.2mm;

[0047] e. Use a twist drill to machine 30 M4 self-tapping screw holes for assembling the mating parts. The diameter requirement is φ3.68mm±0.08mm, and the positional accuracy requirement is 0.2mm.

[0048] f. Use a Φ15mm end mill to machine the end faces of the two M6 threaded holes for mounting pressure heaters, with a perpendicularity requirement of 0.15mm.

[0049] g. Use a step drill and tap to machine four M6 threaded holes (three), and use a step drill and tap to machine two M6 threaded holes (five) for installing pressure heaters. The thread requirement is M6X1-6H.

[0050] h. Use a step drill to rough machine the inlet and outlet pipe holes, and then use a reamer to finish machine the inlet and outlet pipe holes. The hole diameters are required to be φ15.775mm±0.043mm and φ20.425mm±0.043mm, respectively.

[0051] A further improvement of the present invention is that: in step a of step C, the cutter disc with a diameter of φ50mm is provided with a total of 8 cutting tools, of which 6 are finishing cutting tools and 2 are textured cutting tools. When installing the cutting tools, the textured cutting tools are 0.02mm higher than the finishing cutting tools.

[0052] A further improvement of the present invention is that: in step b of step C, the cutter disc with a diameter of φ32mm is provided with a total of 4 cutting tools, of which 3 are finishing cutting tools and 1 is a textured cutting tool. When installing the cutting tools, the textured cutting tool is 0.02mm higher than the finishing cutting tool.

[0053] Compared with the prior art, the present invention has the following advantages:

[0054] By scientifically and rationally allocating processing content, the processing cycle time is more balanced, the cycle time of bottleneck processes is reduced by 45% compared with traditional solutions, and the overall processing line balance rate is increased from 80.3% to 96.6%.

[0055] This invention reduces data instability caused by deformation of the blank surface and side positioning reference surface, and uses stable machined holes and machined surfaces for positioning and machining, improving the stability of key dimension data by 80%. Attached Figure Description

[0056] Figure 1 This is a top view of the electrical control box housing;

[0057] Figure 2 This is a bottom view of the electrical control box housing;

[0058] Figure 3 This is a front view of the electrical control box housing;

[0059] Figure 4 This is a rear view of the electrical control box housing;

[0060] Figure 5 This is a left view of the electrical control box housing;

[0061] Figure 6 This is a right view of the electrical control box housing;

[0062] Numbering in the diagram: 1-Blank positioning reference surface, 2-Blank positioning surface, 3-Upper cover plate assembly surface, 4-Bolt mounting hole, 5-Support pin mounting hole, 6-Insulating sheet surface, 7-Connector hole, 8-M6 threaded hole II, 9-Lower cover plate assembly surface, 10-Water channel surface, 11-M5 threaded hole, 12-Inverter grid assembly M4 self-tapping screw hole, 13-M8 threaded hole I, 14-M6 threaded hole IV, 15-Pre-installation positioning hole I, 16-Lower cover plate assembly surface M5 self-tapping screw hole, 17-Lower cover plate positioning mounting hole, 18-Cooling cover plate mounting positioning pin, 19-Dust plug sealing hole, 20-B+ connector hole, 21-M6 threaded hole I, 22-Upper cover plate positioning reference hole, 23-Hand component positioning pin, 24-Circuit component positioning pin, 25- M6 threaded hole five, 26-M6 threaded hole three, 27-Water inlet pipe hole, 28-M8 threaded hole two, 29-Pre-installation positioning hole two, 30-Water outlet pipe hole, 31-M5 self-tapping screw hole, 32-Positioning hole for mounting connector, 33-Inverter grid assembly mounting positioning pin, 34-M4 self-tapping screw hole for B+ connector, 35-Limiting hole, 36-M4 self-tapping screw hole for assembling hand parts, 37-Oval positioning pin. Detailed Implementation

[0063] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Elements and features described in one embodiment of the present invention can be combined with elements and features shown in one or more other embodiments. It should be noted that, for clarity, representations and descriptions of components and processes unrelated to the present invention and known to those skilled in the art are omitted in the description. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0064] The present invention will be further described below with reference to the accompanying drawings:

[0065] A processing method for the housing of an electrical control box in new energy vehicles includes the following steps:

[0066] A. Mount the blank of the electrical control box to be processed onto the machining fixture, and use the three blank positioning reference surfaces 1 and 2 as defined in the drawing for positioning:

[0067] a. Use a milling cutter with a diameter of φ50mm to rough mill the assembly surface 3 of the upper cover plate, leaving a 0.2mm allowance for finishing. The rough-milled assembly surface 3 of the upper cover plate is the process positioning surface for steps B and C.

[0068] b. Use a PCD step drill reamer to finish machine 18 bolt mounting holes 4, with the hole diameter controlled at 17*φ7.8mm±0.1mm and 1*φ6.5mm±0.1mm;

[0069] c. Use a step drill and a reamer to machine the four support pin mounting holes 5 on the assembly surface 3 of the upper cover plate, with the hole diameter controlled at φ8mm±0.018mm.

[0070] d. Use a φ8mm diameter corrugated end mill and a φ8mm diameter coated end mill to machine the insulating sheet 6, requiring a surface flatness of 0.1mm;

[0071] e. Use a milling cutter bar with a diameter of φ25mm to machine the end faces of the three connector holes 7 and the four M6 threaded holes 8, requiring a surface flatness of 0.1mm;

[0072] f. Use a φ8mm forming milling cutter and a φ8mm chamfering cutter to machine three connector holes 7, requiring a full circumferential width of 0.2mm;

[0073] g. Use a step drill to machine the M5 self-tapping screw hole 31 for installing the connector, with an inner diameter of 16*φ4.64mm±0.1mm;

[0074] h. Use a step drill to machine the positioning hole 32 for installing the connector, with the inner diameter of the hole being 2*φ3.5mm±0.1mm and 1*φ3.7mm±0.1mm respectively;

[0075] i. Use a step drill and tap to machine four M6 threaded holes -21, with thread requirements of M6X1.0-6H;

[0076] B. Position and clamp the two bolt mounting holes 4 and the upper cover plate assembly surface 3 processed in step A, and rough machine the lower cover plate assembly surface 9 and related hole system:

[0077] a. Roughly machine the lower cover plate assembly surface 9 and the two water channel surfaces 10 using a milling cutter bar with a diameter of φ32mm, leaving a 0.2mm allowance for finishing;

[0078] b. Use a step drill and tap to machine 33 M5 threaded holes 11 for installing cooling covers. The thread requirement is M5X0.8-6H.

[0079] c. Use a φ16mm diameter end mill to machine the mounting end faces of 18 bolt mounting holes 4 and the end faces of 10 inverter grid assembly M4 self-tapping screw holes 12, requiring a face wheel width of 0.4mm.

[0080] d. Use a φ20mm end mill to machine the end face of one M8 threaded hole 13, one M8 threaded hole 28, three M6 threaded holes 26, six M6 threaded holes 14, two pre-installation positioning holes 15, and one pre-installation positioning hole 29. The surface distance tolerance is required to be ±0.3mm.

[0081] e. Use a step drill and tap to machine one M8 threaded hole 13, and use a step drill and tap to machine one M8 threaded hole 28. The thread requirement is M8X1.25-6H.

[0082] f. Use a step drill and tap to machine three M6 threaded holes (3.26) and six M6 threaded holes (4.14) (M6X1-6H thread requirement).

[0083] g. Use a step drill to machine two pre-installation positioning holes 15 and one pre-installation positioning hole 29, each with a diameter of φ10mm ± 0.2mm.

[0084] C. Position and clamp the two bolt mounting holes 4 and the upper cover plate assembly surface 3 processed in step A, and then finish machine the lower cover plate assembly surface 9 and related hole system:

[0085] a. Use a φ50mm diameter milling cutter to finish machine the lower cover plate assembly surface 9, and use a polishing brush to remove the burrs that are easy to fall off the edges. The surface roughness requirement is Ra1.0mm~5.0mm, and the surface flatness requirement is 0.2mm. The φ50mm diameter cutter head has a total of 8 cutting tools, of which 6 are finishing cutting tools and 2 are textured cutting tools. When installing the cutting tools, the textured cutting tools are 0.02mm higher than the finishing cutting tools.

[0086] b. Use a φ32mm diameter milling cutter to finish the waterway surface 10. The surface roughness requirement is Ra1.0mm~5.0mm. The φ32mm diameter cutter head has a total of 4 cutting tools, of which 3 are finishing cutting tools and 1 is a textured cutting tool. When installing the cutting tools, the textured cutting tool is 0.02mm higher than the finishing cutting tool.

[0087] c. Use a PCD step drill and reamer to machine 23 M5 self-tapping screw holes on the mounting surface of the lower cover plate, with a thread requirement of φ4.64mm±0.1mm;

[0088] d. Use a step drill and reamer to rough and finish machine the two lower cover plate positioning and mounting holes 17, with a diameter requirement of φ4mm±0.1mm;

[0089] e. Use a PCD tooling tool to machine two cooling cover plates and install positioning pins 18, with a diameter requirement of φ6mm±0.05mm;

[0090] f. Use a PCD tooling tool to machine 7 inverter grid assembly mounting and positioning pins 33, with a diameter requirement of φ4mm±0.1mm;

[0091] g. Use a twist drill and chamfering tool to machine 12 M4 self-tapping screw holes for the inverter grid assembly, with a diameter requirement of φ3.68mm±0.1mm;

[0092] h. Use a φ16mm diameter end mill to machine the mounting end face of the dust plug sealing hole 19, requiring a face wheel width of 0.4mm;

[0093] i. Use a step drill and tap to machine an M6 threaded hole -21, with a thread requirement of M6X1.0-6H;

[0094] j. Use a step drill, reamer, and broach to machine the dust plug sealing hole 19, with a diameter requirement of φ8.2mm±0.1mm;

[0095] k. Use a milling cutter with a diameter of φ32mm to machine the end face of the B+ connector hole 20, with a surface distance tolerance of ±0.3mm.

[0096] 1. Use a rough and fine integrated drill and reamer to machine the B+ connector hole 20, with a diameter requirement of φ36.3mm±0.03mm;

[0097] n. Use a twist drill to machine two M4 self-tapping screw holes 34 for installing B+ connectors, with a diameter requirement of φ3.68mm±0.08mm;

[0098] m. Use a drill and milling cutter to machine the limiting hole 35 for installing the B+ connector. The diameter requirement is φ3.2mm±0.08mm, and the positional accuracy requirement is 0.2mm.

[0099] D. Position and clamp the two lower cover plate positioning mounting holes 17 and the lower cover plate assembly surface 9 processed in step C, and finish machine the upper cover plate assembly surface 3 and multiple holes:

[0100] a. Use a φ50mm diameter cutter head to precision machine the upper cover plate assembly surface 3, and use a polishing brush to remove the burrs that are easy to fall off the edges. The surface roughness requirement of the upper cover plate assembly surface is Ra max16, and the surface flatness requirement is 0.15mm.

[0101] b. Use a step drill and reamer to rough and finish machine two positioning reference holes 22 on the upper cover plate. The diameter requirement is φ10.1mm±0.05mm, and the positional accuracy requirement is 0.2.

[0102] c. Use a PCD tooling tool to machine 30 locating pins 23 for the main components and 3 locating pins 24 for the circuit components. The positional accuracy requirement is 0.2, and the hole diameter requirement is φ4mm±0.05.

[0103] d. Use an 8mm diameter end mill to machine the mounting faces of all circuit components and the three waist-shaped locating pins 37, with a profile accuracy of 0.4mm and a position accuracy of 0.2mm.

[0104] e. Use a twist drill to machine 30 M4 self-tapping screw holes for the assembly of the two parts, with a diameter requirement of φ3.68mm±0.08mm and a positional accuracy requirement of 0.2mm;

[0105] f. Use a Φ15mm end mill to machine the end faces of two M6 threaded holes (5.25mm) for mounting pressure heaters, with a perpendicularity requirement of 0.15mm.

[0106] g. Use a step drill and tap to machine four M6 threaded holes (3.26) and two M6 threaded holes (5.25) for installing pressure heaters. The thread requirement is M6X1-6H.

[0107] h. Use a step drill to rough machine the inlet pipe hole 27 and the outlet pipe hole 30, and then use a reamer to finish machine the inlet pipe hole 27 and the outlet pipe hole 30. The hole diameters are required to be φ15.775mm±0.043mm and φ20.425mm±0.043mm, respectively.

[0108] The original two processes have been split into four processes: 1. Rough machining of the upper cover plate assembly surface and related hole system; 2. Rough machining of the lower cover plate assembly surface, water channel surface and related hole system; 3. Finish machining of the lower cover plate assembly surface, water channel surface and related hole system; 4. Finish machining of the upper cover plate assembly surface and related hole system. The processing content is scientifically and rationally allocated, making the processing cycle more balanced. The cycle time of the bottleneck process is reduced by 45% compared with the traditional solution, and the overall processing line balance rate is increased from 80.3% to 96.6%.

[0109] The roughing of the upper cover plate assembly surface is done in sequence 1, and the finishing is done in sequence 4. The roughing of the lower cover plate assembly surface and the water channel surface is done separately, with roughing done in sequence 2 and finishing done in sequence 3. The flatness of the upper cover plate assembly surface after roughing is better and more stable than the blank surface. Sequences 2 and 3 use the rough-machined upper cover plate assembly surface to perform roughing and finishing of the lower cover plate assembly surface and the water channel surface. Sequence 4 uses the finishing lower cover plate assembly surface and the reference hole for positioning. This separate roughing and finishing process allows the internal stress of the product to be fully released after the product is released from the clamp. The flatness data of the upper cover plate assembly surface, lower cover plate assembly surface, and water channel surface are stable, reducing the data instability caused by the deformation of the blank surface and the side positioning reference surface. Using stable machined holes and machined surfaces for positioning improves the process stability index of key dimensional data by 80%.

[0110] Finally, it should be noted that although the present invention and its advantages have been described in detail above, it should be understood that various changes, substitutions, and modifications can be made without departing from the spirit and scope of the invention as defined by the appended claims. Moreover, the scope of the invention is not limited to the specific embodiments of the processes, apparatus, means, methods, and steps described in the specification. Those skilled in the art will readily understand from the disclosure of this invention that existing and future processes, apparatus, means, methods, or steps that perform substantially the same function or obtain substantially the same result as the corresponding embodiments described herein can be used according to the present invention. Therefore, the appended claims are intended to include such processes, apparatus, means, methods, or steps within their scope.

Claims

1. A processing method suitable for a new energy vehicle electric control box shell, characterized in that: The method comprises the following steps: A. The blank of the electric control box shell to be processed is clamped on the machining clamp, and three blank positioning reference surfaces (1) and three blank positioning surfaces (2) defined by the drawing are used for positioning: a. The upper cover plate assembly surface (3) is roughly milled by a milling cutter with a diameter of φ50 mm, and the upper cover plate assembly surface (3) is precisely processed with a 0.2 mm allowance, and the roughly milled upper cover plate assembly surface (3) is the process positioning surface of steps B and C; b. The 18 bolt mounting holes (4) are precisely processed by a PCD stepped drill and a reamer, and the hole diameter is controlled to be 17*φ7.8 mm±0.1 mm and 1*φ6.5 mm±0.1 mm; c. The four support pin mounting holes (5) on the upper cover plate assembly surface (3) are processed by a stepped drill and a reamer, and the hole diameter is controlled to be φ8 mm±0.018 mm; d. The insulating sheet surface (6) is processed by a wave tooth end mill with a diameter of φ8 mm and a coated end mill with a diameter of φ8 mm, and the surface flatness is required to be 0.1 mm; e. The end surfaces of the three connector holes (7) and the end surfaces of the four M6 threaded holes two (8) are processed by a milling cutter bar with a diameter of φ25 mm, and the surface flatness is required to be 0.1 mm; f. The three connector holes (7) are processed by a forming milling cutter with a diameter of φ8 mm and a chamfering cutter with a diameter of φ8 mm, and the surface full circumference runout is required to be 0.2 mm; g. The M5 self-tapping screw holes (31) for mounting the connector are processed by a stepped drill, and the hole diameter is controlled to be 16*φ4.64 mm±0.1 mm; h. The positioning holes (32) for mounting the connector are processed by a stepped drill, and the hole diameter is controlled to be 2*φ3.5 mm±0.1 mm and 1*φ3.7 mm±0.1 mm, respectively; i. The four M6 threaded holes one (21) are processed by a stepped drill and a tap, and the thread is required to be M6X1.0-6H; B. The two bolt mounting holes (4) and the upper cover plate assembly surface (3) processed in step A are used for positioning and clamping, and the lower cover plate assembly surface (9) and the related hole system are roughly processed: a. The lower cover plate assembly surface (9) and two waterway surfaces (10) are roughly processed by a milling cutter bar with a diameter of φ32 mm, and the precisely processed allowance is 0.2 mm; b. The 33 M5 threaded holes (11) for mounting the cooling cover plate are processed by a stepped drill and a tap, and the thread is required to be M5X0.8-6H; c. The mounting end surfaces of the 18 bolt mounting holes (4) and the end surfaces of the 10 inverter grid plate assembly M4 self-tapping screw holes (12) are processed by an end mill with a diameter of φ16 mm, and the surface runout is required to be 0.4 mm; d. The end surfaces of one M8 threaded hole one (13), one M8 threaded hole two (28), three M6 threaded hole three (26), six M6 threaded hole four (14), two pre-installation positioning hole one (15) and one pre-installation positioning hole two (29) are processed by an end mill with a diameter of φ20 mm, and the surface distance tolerance is required to be ±0.3 mm; e. One M8 threaded hole one (13) is processed by a stepped drill and a tap, and one M8 threaded hole two (28) is processed by a stepped drill and a tap, and the thread is required to be M8X1.25-6H; f. Drill and tap 3 M6 threaded holes three (26) and 6 M6 threaded holes four (14) with a step drill and tap, thread requirement M6X1-6H; g. Drill 3 φ10mm 2 pre-installation positioning hole one (15) and 1 pre-installation positioning hole two (29) with a step drill, diameter requirement φ10mm±0.2mm; C. With the two bolt mounting holes (4) and the upper cover plate assembly surface (3) processed in step A positioned clamped, finish machining the lower cover plate assembly surface (9) and related hole system: a. Finish machining the lower cover plate assembly surface (9) with a diameter φ50mm milling cutter bar, and remove the edge easy to fall burr with a polishing brush, the surface roughness requirement Ra1.0mm~5.0mm, the surface flatness requirement 0.2mm, the diameter φ50mm cutter disc is provided with 8 cutter particles, of which 6 are finishing cutter particles and 2 are textured cutter particles, when installing the cutter particles, the textured cutter particles are 0.02mm higher than the finishing cutter particles; b. Finish machining the waterway surface (10) with a diameter φ32mm milling cutter bar, the surface roughness requirement Ra1.0mm~5.0mm; c. Drill and ream 23 lower cover plate assembly surface M5 self-tapping screw holes (16) with a PCD step drill, thread requirement φ4.64mm±0.1mm; d. Drill and ream 2 lower cover plate positioning installation holes (17) with a step drill and reamer, diameter requirement φ4mm±0.1mm; e. Drill 2 cooling cover plate installation positioning pins (18) with a PCD sleeve cutter, diameter requirement φ6mm±0.05mm; f. Drill 7 inverter grid plate assembly installation positioning pins (33) with a PCD sleeve cutter, diameter requirement φ4mm±0.1mm; g. Drill and chamfer 10 inverter grid plate assembly installation M4 self-tapping screw holes (12) with a twist drill and chamfer cutter, diameter requirement φ3.68mm±0.1mm; h. Drill the installation end face of the dust plug sealing hole (19) with a diameter φ16mm end mill, the requirement face roundness 0.4mm; i. Drill M6 threaded hole one (21) with a step drill and tap, thread requirement M6X1.0-6H; j. Drill and ream the dust plug sealing hole (19) with a step drill, reamer and reverse broach, diameter requirement φ8.2mm±0.1mm; k. Mill the end face of the B+linker hole (20) with a diameter φ32mm milling cutter bar, the requirement face distance tolerance ±0.3mm; l. Drill and ream the B+linker hole (20) with a rough and fine integrated drill reamer, diameter requirement φ36.3mm±0.03mm; n. Drill 2 M4 self-tapping screw holes (34) for installing B+linker with a twist drill, diameter requirement φ3.68mm±0.08mm; m. Drill the limiting hole (35) for installing B+linker with a drill milling cutter, diameter requirement φ3.2mm±0.08mm, position degree requirement 0.2mm; D. With the two lower cover plate positioning installation holes (17) and the lower cover plate assembly surface (9) processed in step C positioned clamped, finish machining the upper cover plate assembly surface (3) and multiple holes: a. Use a diameter of 50 mm cutter to finish the upper cover plate assembly surface (3), and use a polishing brush to remove the edge of the easy to fall off burr, the roughness of the upper cover plate assembly surface is required to be Ra max 16, and the surface flatness is required to be 0.15 mm; b. Use a step drill and a reamer to rough and finish the two upper cover plate positioning reference holes (22), the diameter is required to be φ10.1 mm±0.05 mm, the position degree is required to be 0.2, the diameter of 32 mm cutter has 4 cutter particles, of which 3 are finishing cutter particles and 1 is a knurl cutter particle, when installing the cutter particles, the knurl cutter particle is 0.02 mm higher than the finishing cutter particle; c. Use PCD sleeve cutter to process 30 opponent piece positioning pin columns (23) and 3 circuit assembly positioning pin columns (24), the position degree is required to be 0.2, and the hole diameter is required to be φ4 mm±0.05; d. Use a diameter of 8 mm end mill to process all circuit assembly mounting end surfaces and 3 waist type positioning pin columns (37), the profile degree is required to be 0.4 mm, and the position degree is required to be 0.2 mm; e. Use a twist drill to process 30 opponent piece assembly M4 self-tapping screw holes (36), the diameter is required to be φ3.68 mm±0.08 mm, and the position degree is required to be 0.2 mm; f. Use a Φ15 mm end mill to process the end surface of two M6 threaded hole five (25) for installing pressure heater, the surface perpendicularity is required to be 0.15 mm; g. Use a step drill and a tap to process four M6 threaded hole three (26), and use a step drill and a tap to process two M6 threaded hole five (25) for installing pressure heater, the thread is required to be M6X1-6H; h. Use a step drill to rough process the water inlet pipe hole (27) and the water outlet pipe hole (30), and then use a reamer to finish process the water inlet pipe hole (27) and the water outlet pipe hole (30), the hole diameters are required to be φ15.775 mm±0.043 mm and φ20.425 mm±0.043 mm respectively.

Images