Machining method for weight reduction groove of inner cavity of cartridge receiver and cartridge receiver

Abstract

The invention discloses a machining method for a weight reduction groove in an inner cavity of a casing and the casing, and the machining method for the weight reduction groove in the inner cavity of the casing comprises the following steps that a milling cutter with the diameter more than twice larger than the radial allowance width of the weight reduction groove in the inner cavity of the casing is used, and the milling cutter extends into the inner cavity of the casing in the axial direction; performing plunge milling along the axial direction of the weight reduction groove in a deep hole pecking drilling mode, and performing plunge milling for multiple times at intervals in the circumferential direction to form a plurality of lace grooves and assembly bosses; wherein in the axial plunge milling process, the circumferential direction and the width direction of the radial allowance of the weight reduction groove are combined into one layer, and one-time milling is conducted. The milling cutter with the diameter more than twice larger than the radial allowance width is adopted, the cutting force of the cutter is improved, and the vibration and tipping phenomena in the machining process are reduced; the machining efficiency is improved by adopting the machining mode that one cutter penetrates through the milling circumferential direction and the width direction from top to bottom, the main stress of the milling cutter in the drilling and milling process is the axial force, the radial cutting force acting on a machine tool is greatly reduced, and the deformation of the casing can be reduced.

Description

Technical Field

[0001] The invention relates to the technical field of mechanical processing of aircraft engine parts, and in particular to a processing method for a weight-reducing groove in an inner cavity of a casing and a casing. Background Art

[0002] The design of aircraft engine parts will take weight reduction into consideration. Reducing the weight of the casing can improve the performance and efficiency of the aircraft, and at the same time help to improve the reliability and service life of the engine. Therefore, many casings will mill the excess parts of the assembly to reduce weight.

[0003] For example, a certain type of low-pressure turbine casing is an important core component of a certain type of engine. It has a complex structure, thin walls, large diameter, high dimensional accuracy, and many slots. It needs to mill a large number of assembly bosses and weld a large number of parts. It is easy to deform during processing, which affects its processing accuracy and quality, and thus affects the overall performance of the engine. The material of the turbine casing is GH4169. The total length of the turbine casing is 187.2mm, the maximum diameter is 682mm, and the thinnest wall thickness is 2.5mm. It is a typical welded thin-walled part. The inner ring of the turbine casing has a circle of weight reduction grooves 1, see Figure 1 Because it is located 103.7mm deep in the inner cavity of the receiver, the shortest distance between the groove and the inner wall is 6.5mm. The tool is limited during processing and there is a lot of allowance. There are 7 assembly surfaces in the middle of the weight reduction groove. Since the lace groove is located deep, the general integral milling cutter and the machine tool spindle cannot go deep into the inner cavity of the receiver, and the tool needs to be lengthened to go deep into the receiver for processing.

[0004] The following problems exist when processing the weight-reducing grooves, assembly surfaces and mounting holes in the inner cavity of the casing: 1) The inner ring weight-reducing groove has a large allowance and a deep position, which limits the processing space, has poor rigidity, low processing efficiency and high tool cost; 2) There are 7 assembly surfaces in the middle of the weight-reducing groove that are deep, have high precision, poor processing rigidity and are difficult to guarantee dimensional accuracy; 3) There are multiple mounting holes on the weight-reducing groove, resulting in intermittent cutting, low processing efficiency and high tool loss.

[0005] At present, there are two methods for processing the weight-reducing groove in the inner cavity of the receiver: 1. Using the traditional The rod milling cutter is used for layered milling. Due to the large cutting force, the full cutting cannot be performed, the tool overhang is deep, and the tool rigidity is poor, so layered processing is required in the X and Z directions. The milling allowance for each layer is approximately 1mm (X direction) and 5mm (Z direction), and the weight reduction groove has a larger allowance of approximately 6mm and 37.5mm in the X and Z directions. The X direction is divided into 6 layers for processing (1mm per layer), and the Z direction is divided into 8 layers for processing (5mm per layer). A total of 48 milling times are performed, and 1 milling cutter is required each time. The price of each tool is about 1,723.89 yuan, and the total processing time is about 82,746 yuan. The tool cost is extremely high, and the processing time is approximately 43.3min*48=2079min=34.65h. The processing efficiency is extremely low, and the casing deformation is large. ② Use The large diameter T-type milling cutter has better rigidity and larger cutting area. At the same time, the cutting depth can be increased to improve the processing efficiency. The X direction is divided into 3 layers (2mm per layer), and the Z direction is divided into 6 layers (7mm per layer). A total of 18 passes are required, and a total of 18*6=108 blades are required. The price of each blade is about 88.5 yuan, and the total tool cost is 9558 yuan. Although the tool cost is acceptable, the processing time is about 65min*18=1170min=19.5h, the processing efficiency is not high, and the casing deformation is large. Therefore, it is necessary to improve the existing processing method of the weight reduction groove in the casing cavity. Summary of the invention

[0006] The invention provides a method for processing a weight-reducing groove in a casing inner cavity and a casing, so as to solve the technical problems of high tool loss, low processing efficiency and large casing deformation existing in the prior art.

[0007] According to one aspect of the present invention, a method for processing a weight-reducing groove in a casing inner cavity is provided, comprising the following contents:

[0008] Use a milling cutter with a diameter more than twice the radial margin width of the weight-reducing groove in the inner cavity of the casing, and extend the milling cutter axially into the inner cavity of the casing;

[0009] The deep hole pecking method is used to insert milling along the axial direction of the weight-reducing groove, and insert milling is performed multiple times at intervals along the circumference to form a number of lace grooves and assembly bosses;

[0010] Among them, when milling along the axial direction, the circumferential direction and the width direction of the radial margin of the weight-reducing groove are combined into one layer and milled through with one cut.

[0011] Furthermore, the diameter of the milling cutter is 2-4 times the radial margin of the weight-reducing groove.

[0012] Furthermore, the deep hole pecking drilling method is to drill 2-3mm from top to bottom in the axial direction and retreat 0.5-1mm, repeatedly advancing until drilling through.

[0013] Furthermore, the specific method of inserting and milling the radial allowance of the weight-reducing groove in the axial and circumferential directions by deep hole pecking drilling includes:

[0014] The mounting holes on the radial margin of the weight-reducing groove in the inner cavity of the casing are first plunge-milled by symmetrical milling to form several sections of margin bosses;

[0015] The excess boss is then plunge milled in the axial and circumferential directions.

[0016] Furthermore, the symmetrical milling is to start the milling with the axial symmetry axis of the mounting hole as the starting point, and then perform left and right plunge milling until all the allowances at the mounting hole position are removed.

[0017] Furthermore, the excess boss is plunge milled from any end of the excess boss in the axial direction and the circumferential direction to form a lace groove.

[0018] Furthermore, the circumferential step distance of the milling cutter is calculated according to the following formula:

[0019] S = π × D × Z / N;

[0020] Wherein S is the circumferential pitch; D is the diameter of the milling cutter; Z is the number of teeth of the milling cutter; and N is the rotation speed of the milling cutter. The number of teeth of the milling cutter (4) is 6-8, and the rotation speed of the milling cutter (4) is 500-600 r / min.

[0021] Furthermore, the feed rate of the milling cutter is 50-70 mm / r.

[0022] Furthermore, it also includes the use of The drill bit is used to clean the intersection of the lace groove and the assembly boss.

[0023] According to yet another aspect of the present invention, there is also provided a casing, which is manufactured by using the above-mentioned processing method for the weight-reducing groove in the inner cavity of the casing.

[0024] The present invention has the following beneficial effects:

[0025] The present invention adopts a milling cutter with a diameter more than twice the width of the radial margin of the weight-reducing groove in the inner cavity of the casing to provide sufficient rigidity and force support, and at the same time, the part of the milling cutter involved in cutting does not exceed the center of the milling cutter, thereby improving the cutting force of the tool and reducing vibration and chipping during processing; during processing, a deep hole pecking method is used to insert milling along the axial direction of the weight-reducing groove and insert milling multiple times at intervals along the circumferential direction; by adopting a milling cutter with a diameter more than twice the width of the radial margin of the weight-reducing groove in the inner cavity of the casing, the present invention can combine the circumferential direction and the width direction of the radial margin of the weight-reducing groove into one when the milling cutter inserts milling along the axial direction The milling is carried out layer by layer with one cutter. This processing method of milling from top to bottom in the circumferential direction and the width direction with one cutter improves the processing efficiency, and the main force applied to the milling cutter during the drilling and milling process is the axial force, which greatly reduces the radial cutting force of the milling cutter on the casing. Even if the tool overhang length is large, it still has high processing rigidity, can reduce the deformation of the casing, and ensure processing stability; the milling cutter is inserted and milled from top to bottom, and the contact area between the milling cutter and the casing is small, which makes the tool less stressed and can avoid the problems of tool letting go and tool vibration. At the same time, the axial force processing of the casing will not cause casing deformation.

[0026] In addition to the above-described objects, features and advantages, the present invention has other objects, features and advantages. The present invention is further described in detail below. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The drawings constituting a part of this application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0028] Figure 1 This is a schematic diagram of the inner structure of the receiver.

[0029] Figure 2 Schematic diagram of the location of the milling mounting holes.

[0030] Figure 3 Schematic diagram of the milling allowance boss.

[0031] Figure 4 This is a schematic diagram of the structure after milling is completed.

[0032] Figure 5 Schematic diagram of the milling path.

[0033] Figure 6 This is a real picture of the milling effect of the weight-reducing groove on the receiver.

[0034] In the figure: 1-weight reduction groove; 2-lace groove; 3-assembly boss; 4-milling cutter. DETAILED DESCRIPTION

[0035] The embodiments of the present invention are described in detail below with reference to the accompanying drawings. However, the present invention can be implemented in many different ways as defined and covered below.

[0036] The embodiment of the first aspect of the present invention provides a method for processing a weight-reducing groove 1 in a casing inner cavity, comprising the following contents:

[0037] Use a milling cutter 4 with a diameter more than twice the radial margin width of the weight-reducing groove 1 in the inner cavity of the casing, and extend the milling cutter 4 axially into the inner cavity of the casing;

[0038] A deep hole pecking method is used to perform axial milling along the weight-reducing groove 1, and multiple circumferential milling is performed at intervals to form a plurality of lace grooves 22 and assembly bosses 3; wherein, when milling along the axial direction, the circumferential direction and width direction of the radial margin of the weight-reducing groove 1 are combined into one layer and milled through from top to bottom.

[0039] Specifically, see Figure 1In this embodiment, the weight reduction groove 1 is located at 103.7 mm deep in the inner cavity of the casing, and the shortest distance between the groove and the inner wall is 6.5 mm. When the integral milling cutter 4 is used for processing, the machine tool spindle cannot penetrate into the inner cavity of the casing, and the tool needs to be lengthened for deep processing in the casing, which has the problem of extremely poor tool rigidity. The processing position margin of the weight reduction groove 1 in the inner cavity of the casing is large, and 7 assembly bosses 3 and 7 lace grooves 2 need to be milled out, and the 7 assembly bosses 3 and 7 lace grooves 2 are arranged at intervals along the circumferential direction. The present invention uses a milling cutter 4 with a diameter more than twice the radial allowance width of the weight reduction groove 1 in the inner cavity of the casing. The diameter of the tool cannot be too small so that the tool processing rigidity and force can meet the requirements. At the same time, the part of the tool involved in cutting should not pass through the center of the tool, because the center of the tool is the weakest place of the cutting force, the cutting line speed is 0, and it is in a squeeze cutting state, which increases the processing vibration and causes the milling cutter 4 to break. After the tool offsets the center by a distance, the contact point at the bottom of the tool is not the center of the tool when processing the casing, avoiding the tool center that does not have the cutting function, improving the cutting force of the tool, and thus improving the processing efficiency. The area involved in cutting cannot be too small. If it is too small, it will affect the rigidity of the tool and easily break the edge. Therefore, it is best to select a tool with a diameter more than twice the radial allowance width. The present invention adopts a milling cutter with a diameter greater than twice the width of the radial margin of the weight-reducing groove in the inner cavity of the casing, so that the milling cutter can combine the radial margin of the weight-reducing groove in the circumferential direction and the width direction into one layer and mill through with one cut when milling along the axial direction. The method of milling the circumferential and width margins from top to bottom with one cut improves the processing efficiency while reducing the radial cutting force of the milling cutter on the casing, reduces the deformation of the casing, and ensures the processing stability. In this embodiment, because the radial margin of the weight-reducing groove 1 is greater than 6mm, in order to improve the processing efficiency, the tool diameter should be 13-25mm so that the circumferential and width margins can be milled from top to bottom with one cut during processing. According to the rigidity of the tool (deep processing position, small tool, poor rigidity) and the processing material (high-temperature alloy, difficult-to-process material), a tool with a larger diameter is selected as much as possible, so the diameter of 24-25mm is the best.

[0040] The deep hole pecking method is used to insert milling the radial allowance of the weight-reducing groove 1 in the axial and circumferential directions. The deep hole pecking method is to drill from top to bottom in the axial direction, drill down about 2mm and retreat about 1mm, and repeatedly feed until drilling through. Insert milling can also be called Z-axis milling method. The main force during processing is the axial cutting force, which greatly reduces the cutting force acting on the radial direction of the machine tool. Even if the tool overhang length is large, it still has high processing rigidity, can reduce the deformation of the casing, and ensure processing stability. Insert milling is performed on the radial allowance of the weight-reducing groove 1 in the axial direction, so that the casing is subjected to axial force and is not easily deformed. When insert milling in the axial direction, the circumferential direction and width direction of the radial allowance of the weight-reducing groove 1 are combined into one layer and milled through with one cut. That is, during processing, one cut is used to penetrate the circumferential direction and width direction allowance from top to bottom, which can improve processing efficiency. The processing method adopted in the prior art is layered milling along the circumferential direction, width direction and axial direction of the radial allowance, and side edge milling. The tool is subjected to radial and axial forces at the same time, the contact area between the tool and the casing is large, and the force is large. The large force can easily cause deformation of the casing. In addition, the processing position is deep, the tool overhang is long, and the tool rigidity is poor, so problems such as tool letting go and tool vibration may easily occur.

[0041] The present invention adopts a milling cutter 4 with a diameter more than twice the width of the radial margin of the weight-reducing groove 1 in the inner cavity of the casing to provide sufficient rigidity and force support, and at the same time, the part where the milling cutter 4 participates in cutting does not exceed the center of the milling cutter 4, thereby improving the cutting force of the tool and reducing vibration and chipping during processing; during processing, a deep hole pecking method is used to insert and mill the radial margin of the weight-reducing groove 1 in the axial and circumferential directions, wherein, during the axial insert milling, the circumferential direction and the width direction of the radial margin of the weight-reducing groove 1 are combined into a layer and milled through with one cutter, and this processing method of milling the circumferential direction and the width direction margin from top to bottom with one cutter improves the processing efficiency, and the main force of the milling cutter 4 during the drilling and milling process is the axial force, which greatly reduces the force acting on the radial cutting force of the machine tool, and even if the tool overhang length is large, it still has high processing rigidity, can reduce casing deformation, and ensure processing stability; the milling cutter 4 inserts and mills from top to bottom, and the contact area between the milling cutter 4 and the casing is small, so that the force on the tool is small, and the problems of tool letting and tool vibration can be avoided. At the same time, the axial force processing of the casing will not cause casing deformation. The present invention adopts a one-cut milling method, and the main cutting position is the bottom edge of the tool. The tool can be sharpened after being worn, and the bottom edge of the tool is generally sharpened 2-3 times. Each casing can be processed by machining a new tool and sharpening it once, and two casings can be processed by sharpening it three times. However, if the layered milling method is adopted, the side edge cannot be sharpened due to wear, and the side edge is easily worn due to large force during milling, resulting in a short tool life.

[0042] In this embodiment, the diameter of the milling cutter 4 is 2-4 times the radial margin of the weight-reducing groove 1; the number of teeth of the milling cutter 4 is 6-8.

[0043] The milling cutter 4 used in the present invention needs to have good rigidity. Since the processing position is at 103.7mm deep in the inner cavity of the casing, the overhang length should be greater than 130mm, and the diameter of the milling cutter 4 cannot be too small. It is preferred that the diameter of the milling cutter 4 is 2-4 times the radial margin of the weight-reducing groove 1, so that the milling cutter 4 has sufficient rigidity. In addition, the diameter of the milling cutter 4 is 2-4 times the radial margin of the weight-reducing groove 1, which can ensure that the circumferential direction and width direction of the radial margin of the weight-reducing groove can be combined into one layer and milled through with one cut when the milling cutter is axially inserted. If a small milling cutter 4 with a diameter less than 2 times the radial margin of the weight-reducing groove 1 is used for processing, the rigidity of the tool is poor, the area of ​​the position to be removed is large, and the margin is large, then the processing efficiency is low. If a large milling cutter 4 with a diameter greater than 4 times the radial margin of the weight-reducing groove 1 is used for layered processing, the rigidity of the tool can be increased, but the processing contact area is large, the cutting force is large, and the tool vibration and tool letting will occur. In addition, the processing position is located deep in the casing, and the size is not convenient to measure, resulting in extremely low processing efficiency. The number of teeth of the milling cutter 4 is 6-8. The use of a milling cutter 4 with a large number of teeth makes the cutting amount of each tooth smaller, and the cutting speed of the milling cutter 4 will be correspondingly accelerated, which is suitable for situations where the processing is difficult, the cutting is relatively complex, and the processing amount is large. The casing of the present invention is made of GH4169 alloy, and the use of a milling cutter 4 with a number of 6-8 teeth can improve the processing efficiency and processing quality.

[0044] In this embodiment, it is preferred to use The rod milling cutter 4 is used for plunge milling to remove the large excess, and then The rod milling cutter 4 performs fine machining, and side milling is used for fine machining to remove joint marks and ensure size. Since full-cut machining is used during rough machining, there is less excess, and fine machining can also be completed in one cut.

[0045] In this embodiment, the deep hole pecking method is to drill 2-3mm from top to bottom along the axial direction and then retreat 0.5-1mm, repeatedly advancing the tool until drilling through. Preferably, the deep hole pecking method is to drill 2mm from top to bottom along the axial direction and then retreat 1mm, and the deep hole pecking method is used for plunge milling, which can effectively reduce cutting force, reduce tool wear, and increase tool life.

[0046] In this embodiment, the specific method of using deep hole pecking to perform plunge milling on the radial allowance of the weight-reducing groove 1 in the axial and circumferential directions includes:

[0047] The mounting holes on the radial margin of the weight-reducing groove 1 in the inner cavity of the casing are first plunge-milled by symmetrical milling to form a plurality of margin bosses;

[0048] The excess boss is then plunge milled in the axial and circumferential directions.

[0049] See also Figure 2The processing position has a mounting seat on the side of the casing, and a through hole is punched in the middle of the mounting seat for installing the gas pipe and oil pipe, which causes intermittent cutting, low processing efficiency, and large tool wear. There are 7 evenly distributed lace grooves 2 in the casing cavity, and each lace groove 2 has 1 to 2 oil inlet or return pipes and air bleed installation holes, a total of 11, and their apertures are and If the tool radius is larger than the tool radius, there will be intermittent cutting during processing, and shaking and tool hitting will occur due to uneven force. If milling is adopted from left to right along the weight reduction groove 1, the wall thickness of the milled part will become thinner after the excess is removed, and the rigidity will be reduced accordingly. When milling to the hole, since the hole diameter is more than half of the tool radius, the cutting position is from milling solid to milling empty and then to milling solid, and there will be intermittent cutting, which will cause uneven tool force, tool shaking, tool hitting, etc., thereby reducing the tool life, and the deformation of the casing at the relatively poor rigidity part will also be relatively large. Therefore, the present invention adopts a symmetrical milling method to first insert milling the mounting hole on the radial excess of the weight reduction groove 1 in the inner cavity of the casing. When the middle hole position is milled first, the left and right excesses are not removed during the milling process, the wall thickness is thicker and uniform, and the casing rigidity is better. When milling the hole position, the tool is limited by the left and right excesses of the processing position, so that the tool cannot shake during intermittent cutting. At this time, the tool hitting is eliminated, thereby improving the tool life. Because the casing wall thickness is uniform and the force is uniform during processing, the casing deformation is relatively reduced. Deformation data: radial runout is 0.1-0.12mm before improvement, and radial runout is 0.03-0.05mm after improvement.

[0050] The position of the mounting hole is processed first, and then the position of the excess boss is processed. On average, 0.3 milling cutters 4 can process a casing. Each cutter costs about 1723.89 yuan, and the total tool cost is about 517.167 yuan, which is low. The time for processing 7 lace grooves 2 is about 1.5h*7=10.5h, with high processing efficiency and high processing stability.

[0051] See also Figure 3 After finishing the allowance of the installation hole, the allowance boss is milled in the axial and circumferential directions. The milling can start from the right side of the allowance boss and end at another allowance boss. The deep hole pecking method is also used, drilling and milling from top to bottom. During the processing, the milling sound and tool wear should be listened to. If any abnormality is found, the tool should be changed immediately.

[0052] In this embodiment, the symmetrical milling is to start milling with the axial symmetry axis of the mounting hole as the starting point, and then perform left and right milling until the allowance at the mounting hole position is completely removed. Specifically, a deep hole pecking method is adopted, drilling and milling from top to bottom, which is equivalent to using the milling cutter 4 as a drill bit to perform deep hole drilling, drilling down 2-3mm and retreating 0.5-1mm, repeatedly feeding the cutter until drilling through. After milling the first cut, the second and third cuts are milled left and right until the allowance at the hole position is completely removed. When the middle hole position is milled first, the left and right allowances are not removed during the milling process, the wall thickness is thick and uniform, and the rigidity of the casing is good.

[0053] In this embodiment, see Figure 4 and Figure 6 , the excess boss is milled from any end of the excess boss in the axial and circumferential directions to form a lace groove 2. Since the diameter of the milling cutter 4 used in the present invention is more than twice the radial dimension of the excess, the radial direction can be milled through in one cut, and then the excess boss is milled in the circumferential direction to form a lace groove 2. The 7 lace grooves 2 and the assembly boss 3 in the present invention are milled and formed by the same processing method. This processing method makes the casing wall thickness uniform and the force uniform, and the casing deformation is relatively reduced.

[0054] In this embodiment, the circumferential pitch of the milling cutter 4 is calculated according to the following formula:

[0055] S = π × D × Z / N;

[0056] Wherein S is the circumferential pitch; D is the diameter of the milling cutter 4; Z is the number of teeth of the milling cutter 4; and N is the rotation speed of the milling cutter 4. The number of teeth of the milling cutter (4) is 6-8, and the rotation speed of the milling cutter (4) is 500-600 r / min.

[0057] In the present invention, the processing depth of the weight reduction groove 1 in the inner cavity of the casing is relatively deep, so a deep hole pecking instruction is used, and 7 places with processing allowances are evenly distributed circumferentially. After one place is programmed, the remaining 6 places can be generated in an array, see Figure 5 , Figure 5 Indicates the milling path, the outermost circle is the position to be processed, the circle and point are the processing points, the processed circle cannot exceed the line at the outermost circle, and should be as close as possible to reduce the finishing allowance. After determining the processing method, the main thing is to determine its radial cutting depth and circumferential step distance. These two parameters affect its processing efficiency and tool life. It is relatively large, with a radial allowance of 6-7mm for the casing, which is less than half of its diameter. It can be processed in one rough machining. Its circumferential step distance can be calculated according to the geometric formula. The step distance formula of milling cutter 4 is: S=π×D×Z / N. According to the processing test, when the speed N is set to 530r / min, the number of teeth Z of milling cutter 4 is set to 8, and D is set to 25mm, it can be calculated through the formula that the step distance of 1.18mm is the best parameter, and the processing effect is the best.

[0058] In this embodiment, the rotation speed of the milling cutter 4 is 500-600r / min, and the feed rate of the milling cutter 4 is 50-70mm / r. Preferably, the rotation speed of the milling cutter 4 is 530r / min, and the feed rate of the milling cutter 4 is 70mm / r. The rotation speed of the milling cutter 4 of the present invention is 500-600r / min, and F is: 50-70mm / r. The tool rotation speed cannot be too fast. A rotation speed greater than 600r / min is prone to excessive processing temperature, tool hardening, tool chipping, and affecting tool life; F feed is too fast, and the cutting amount is too large, which affects the tool force, thereby affecting the tool life and casing processing deformation. After multiple processing tests, it was found that when the rotation speed is 530r / min and the feed is 70mm / r, the tool life, processing time, processing cost, etc. are controlled within the optimal range.

[0059] In this embodiment, it also includes using The drill bit performs root cleaning on the intersection of the lace groove and the assembly boss. After the rod milling cutter is inserted, it is also necessary to use The rod milling cutter side milling is used for finishing to remove the joint marks and ensure the size of the lace groove and assembly boss. The drill bit performs root cleaning on the intersection of the lace groove and the assembly boss to ensure that the root R1 of the intersection of the lace groove and the assembly boss is qualified and the excess is removed.

[0060] According to yet another aspect of the present invention, there is also provided a casing, which is manufactured by using the above-mentioned processing method for the weight-reducing groove in the inner cavity of the casing.

[0061] Table 1 shows the comparison data of the process parameters of the conventional milling method and the processing method of the present invention.

[0062] Table 1 is a comparison between the conventional milling method and the processing method of the present invention.

[0063]

[0064] Note: X, Y and Z directions in the table are the circumferential direction, width direction and axial direction of the radial allowance respectively.

[0065] As can be seen from the above table, by improving the processing method and tool selection, the present invention is relatively The traditional method of layered milling with a rod milling cutter can save 1449 minutes of milling time, 47.7 tools / pieces, and 82229.553 yuan in tool costs. The traditional method of layered milling with a milling cutter can save 540 minutes of milling time, 107.7 tools / pieces, and 9040.833 yuan in tool costs.

[0066] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for processing a weight-reducing groove in a casing cavity, characterized in that: Includes the following: Use a milling cutter (4) having a diameter more than twice the width of the radial margin of the weight-reducing groove (1) in the inner cavity of the casing, and extend the milling cutter (4) axially into the inner cavity of the casing; A deep hole pecking method is used to perform axial milling along the weight-reducing groove (1), and multiple circumferential milling is performed at intervals to form a plurality of lace grooves (2) and assembly bosses (3); wherein, when milling along the axial direction, the circumferential direction and the width direction of the radial margin of the weight-reducing groove (1) are combined into one layer and milled through from top to bottom.

2. The method for processing the weight-reducing groove in the inner cavity of the casing according to claim 1, characterized in that: The diameter of the milling cutter (4) is 2-4 times the radial margin of the weight-reducing groove (1).

3. The method for processing the weight-reducing groove in the inner cavity of the casing according to claim 1, characterized in that: The deep hole pecking drilling method is to drill 2-3mm from top to bottom along the axial direction and retreat 0.5-1mm, repeatedly advancing until drilling through.

4. The method for processing the weight-reducing groove in the inner cavity of the casing according to claim 1, characterized in that: The specific method of using deep hole pecking to perform plunge milling on the radial allowance of the weight-reducing groove (1) in the axial and circumferential directions comprises: A symmetrical milling method is adopted to firstly insert and mill the mounting holes on the radial margin of the weight-reducing groove (1) in the inner cavity of the casing to form a plurality of margin bosses; The excess boss is then plunge milled in the axial and circumferential directions.

5. The method for processing the weight-reducing groove in the inner cavity of the casing according to claim 4, characterized in that: The symmetrical milling is to start milling with the axial symmetry axis of the mounting hole as the starting point, and then perform left and right plunge milling until the position margin of the mounting hole is completely removed.

6. The method for processing the weight-reducing groove in the inner cavity of the casing according to claim 4, characterized in that: The excess boss is milled from any end of the excess boss in the axial direction and the circumferential direction until a lace groove (2) is formed.

7. The method for processing the weight-reducing groove in the inner cavity of the casing according to claim 1, characterized in that: The circumferential pitch of the milling cutter (4) is calculated according to the following formula: S = π × D × Z / N; Wherein S is the circumferential pitch; D is the diameter of the milling cutter (4); Z is the number of teeth of the milling cutter (4); and N is the rotation speed of the milling cutter (4); wherein the number of teeth of the milling cutter (4) is 6-8, and the rotation speed of the milling cutter (4) is 500-600 r / min.

8. The method for processing the weight-reducing groove in the inner cavity of the casing according to claim 7, characterized in that: The feed rate of the milling cutter (4) is 50-70 mm / r.

9. The method for processing the weight-reducing groove in the inner cavity of the casing according to claim 1, characterized in that: The method also includes using a φ2mm drill bit to perform root cleaning on the intersection of the lace groove (2) and the assembly boss (3).

10. A casing, characterized in that: It is manufactured by the processing method of the weight-reducing groove in the inner cavity of the casing as described in any one of claims 1 to 9.

Images