A method for intermittent machining of ultra-large thin-walled casing

Abstract

A method for intermittent machining of an ultra-large thin-walled casing belongs to the technical field of intermittent machining of engine casings, and includes the following steps: step 1, clamping parts; step 2, grinding support plates; step 3, intermittently turning the upper and lower end faces of the support plate wall: the tool path is consistent with the machining profile, and layered machining is performed; the machining process adopts the method of cutting 2 times and polishing 1 time per cut; first intermittently turning the upper end face of the support plate wall, and then intermittently turning the lower end face of the support plate wall; step 4, measuring the upper and lower end faces of the support plate wall: using the tool tip cruise measurement method for measurement, that is, using the CNC program to control the tool tip position so that the tool tip is at a certain distance from the theoretical machining surface, and then using a feeler gauge to measure whether the profile is qualified. The method solves the problems of tool hitting, thin-walled part collapse, poor cutting surface quality, difficult to pass the size and difficult to measure caused by intermittent machining of ultra-large thin-walled casings. It fills the gap in the field of intermittent machining of ultra-large thin-walled casings in China, and provides key technical support for the development of ultra-large spoke-type welded casings.

Description

Technical Field

[0001] The invention belongs to the technical field of intermittent processing of engine casings, and in particular relates to an intermittent processing method for an ultra-large thin-wall casing. Background Art

[0002] The research and development of super-large aircraft engines in China has just started in recent years. The intermittent processing of super-large thin-walled casings, i.e. casings with a diameter of more than φ1700mm, is a blank area. The previous intermittent processing methods could not solve the problems of tool breaking, thin-walled parts collapse, poor cutting surface quality, and unqualified dimensions caused by the intermittent processing of super-large thin-walled casings. Whether the intermittent processing problems of super-large thin-walled casings can be solved plays a vital role in whether super-large thin-walled casings can be successfully developed. Summary of the invention

[0003] The purpose of the present invention is to provide a method for intermittent processing of super-large thin-walled casings, which solves the problems of tool breaking, thin-wall collapse of parts, poor cutting surface quality, difficult size qualification and difficult measurement caused by intermittent processing of super-large thin-walled casings; fills the field of intermittent processing of super-large thin-walled casings in China, and provides key technical support for the development of super-large spoke-type welded casings.

[0004] A method for intermittently processing an ultra-large thin-walled casing comprises the following steps:

[0005] Step 1: Clamp parts:

[0006] Step 1.1, add tightening force on the left and right sides of the support plate arm by screws, and ensure that the tightening force does not cause deformation of the support plate. The tightening force can increase the overall rigidity of the support plate;

[0007] Step 1.2, use an adjustable thin-walled connecting rod to connect the outer ring walls of adjacent support plates in sequence, so that all the outer ring walls of the support plates and the adjustable thin-walled connecting rod form a whole, which can increase the rigidity of the outer ring walls of the support plates and reduce the vibration during the processing of the outer ring walls of the support plates;

[0008] Step 2: Polish the support plate:

[0009] Manually polish the sharp edge of each support plate on the cutting side. After blunting, it can effectively reduce the impact and wear of the sharp edge on the tool, reduce the probability of tool chipping during cutting, increase tool life, and delay the decline of tool cutting performance;

[0010] Step 3: Intermittent turning of the upper and lower end surfaces of the support plate wall:

[0011] The tool path is consistent with the processing surface, and the processing is carried out in layers; the processing process adopts the method of cutting 2 times and finishing 1 time; the upper end surface of the support plate wall is turned intermittently first, and then the lower end surface of the support plate wall is turned intermittently;

[0012] Step 4: Measure the upper and lower end surfaces of the support wall:

[0013] The tool tip cruise measurement method is used for measurement, that is, the position of the tool tip is controlled by the CNC program so that the tool tip is at a certain distance from the theoretical processing surface, and then a feeler gauge is used to measure whether the surface is qualified.

[0014] The adjustable thin-walled connecting rod described in step 1.2 includes connecting rod I and connecting rod II, which are connected by locking screws and nuts, and the ends of connecting rod I and connecting rod II are respectively hinged with U-shaped clamping heads, and the angles of the clamping heads are adjustable.

[0015] The lower surface of the connecting rod I and the upper surface of the connecting rod II are processed into inclined surfaces, and the connecting rod I is placed on the upper part of the connecting rod II so that the inclined surfaces fit together. When the length of the adjustable thin-walled connecting rod is adjusted, the upper surface of the connecting rod I and the lower surface of the connecting rod II always remain parallel.

[0016] The connecting rods I and II are provided with long holes, and locking screws pass through the long holes of the connecting rods I and II and are locked by nuts. By setting the long holes, the length of the adjustable thin-walled connecting rods can be adjusted according to the distance between adjacent support plates.

[0017] In step 3, the upper end face of the support plate wall is intermittently turned using an offset tool, with a spindle speed of 3 to 5 r / min, a feed speed of 0.04 to 0.08 mm / r, and a cutting depth of 0.2 to 0.3 mm per layer.

[0018] In step 3, the lower end face of the support plate wall is intermittently turned using a comb cutter, with a spindle speed of 3 to 5 r / min, a feed speed of 0.04 to 0.08 mm / r, and a cutting depth of 0.2 to 0.3 mm per layer.

[0019] In step 4, the tool tip is at a certain distance from the theoretical processing surface, and the certain distance is selected to be 0.5 mm to 1 mm.

[0020] The beneficial technical effects of the present invention are:

[0021] This patent can solve the problems of tool breaking, thin-walled parts collapse, poor cutting surface quality, and difficult size and measurement caused by intermittent processing of ultra-large thin-walled casings. It fills the gap in the field of intermittent processing of ultra-large thin-walled casings in China and provides key technical support for the development of ultra-large spoke-type welded casings. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic diagram of an oversized thin-walled receiver;

[0023] Figure 2 This is a dimensional drawing of an extra-large thin-walled receiver;

[0024] Figure 3 yes Figure 2 Schematic diagram of the enlarged I direction;

[0025] Figure 4 yes Figure 2 Schematic diagram of the enlarged II direction;

[0026] Figure 5 This is a schematic diagram of the extra-large thin-walled receiver to increase rigidity;

[0027] Figure 6 is a schematic diagram of an adjustable thin-walled connecting rod, where Figure 6 (a) Front view; Figure 6 (b) top view;

[0028] Figure 7 It is a schematic diagram of the adjustment of the adjustable thin-walled connecting rod;

[0029] Figure 8 This is a schematic diagram of the blunt edge of the support wall;

[0030] Fig. 9 It is a schematic diagram of knife tip cruise detection;

[0031] 1- tightening screw, 2- adjustable thin-wall connecting rod, 3- support plate arm, 4- support plate arm, 5- connecting rod I, 6- connecting rod II, 7- U-shaped clamping head, 8- long hole, 9- outer ring wall of support plate. DETAILED DESCRIPTION

[0032] The present invention is further described in detail below with reference to the accompanying drawings and embodiments.

[0033] Example 1

[0034] To explain the processing method in detail, we take a super-large casing welding assembly processed by our factory as an example, and take the super-large thin-walled casing shown in Figure 1 as an example. This part is cast high-temperature alloy, with a diameter of 1800rnm and a wall thickness of 2mm. Figures 2 to 4 As shown in the dimension drawing of the super-large thin-walled casing, the outer ring of the part is welded by multiple support plates. Now it is necessary to intermittently turn the upper and lower sides of the outer ring support plate wall respectively. The intermittent turning surface roughness requirement is Ra3.2, and the surface contour requirement is 0.10.

[0035] A method for intermittently processing an ultra-large thin-walled casing comprises the following steps:

[0036] Step 1: Clamp parts:

[0037] Step 1.1: Figure 5 As shown, the tightening force is increased by tightening screws 1 on the left and right sides of the support plate arm 3, and is observed by measuring the pressure to prevent the support plate from being deformed due to the tightening force. The tightening force can increase the overall rigidity of the support plate.

[0038] Step 1.2: Figure 5As shown, an adjustable thin-walled connecting rod 2 is used to connect the outer ring walls 9 of adjacent support plates in sequence. The length of the adjustable thin-walled connecting rod 2 can be adjusted according to the distance between adjacent support plates, such as Figure 6 and Figure 7 As shown, at this time, all the support plate outer ring walls 9 and the adjustable thin-walled connecting rods 2 form a whole, which can increase the rigidity of the support plate outer ring wall 9 and reduce the vibration during the processing of the support plate outer ring wall;

[0039] The adjustable thin-walled connecting rod specifically includes a connecting rod Ⅰ5 and a connecting rod Ⅱ6, wherein the connecting rod Ⅰ5 and the connecting rod Ⅱ6 are connected by locking screws and nuts, and the ends of the connecting rod Ⅰ5 and the connecting rod Ⅱ6 are respectively hinged with a U-shaped clamping head 7, and the angle of the U-shaped clamping head 7 is adjustable, which is suitable for a variety of support plate spacings and can be extended to other similar parts. It has high flexibility and wide applicability.

[0040] The lower surface of the connecting rod I5 and the upper surface of the connecting rod II6 are processed into inclined surfaces, and the connecting rod I5 is placed on the upper part of the connecting rod II6 so that the inclined surfaces fit together. When the length of the adjustable thin-walled connecting rod 2 is adjusted, the upper surface of the connecting rod I5 and the lower surface of the connecting rod II6 always remain parallel.

[0041] The connecting rods I5 and II6 are provided with long holes 8, and the locking screws pass through the long holes 8 of the connecting rods I5 and II6 and are locked by nuts. The length of the adjustable thin-walled connecting rods 2 can be adjusted according to the distance between adjacent support plates by setting the long holes 8;

[0042] Step 2: Manually polish the sharp edge of each support plate. Figure 8 As shown in the figure, blunting can effectively reduce the impact and wear of the sharp edge on the tool, reduce the probability of tool edge breakage during feed, increase tool life, and delay the decline of tool cutting performance;

[0043] Step 3, intermittent turning of the upper and lower end faces of the support plate wall, the tool path is consistent with the processing profile, and the processing is carried out in layers; in order to reduce the impact force of each intermittent feed and reduce the cutting force of the parts, the processing parameters of low speed, low feed and low cutting depth are adopted. The tool wear is more serious during the intermittent cutting process, and it is very easy to form residual stock in the second half of the cutting. Through multiple cutting accumulations, the residual stock in the second half accumulates more and more, resulting in excessive cutting depth, which is easy to cause tool hitting and part collapse. Therefore, the processing process adopts the method of cutting 2 times and light 1 time per time;

[0044] First, intermittently turn the upper end face of the support plate wall, with a negative rake angle of R0.8, a spindle speed of 4r / min, a feed speed of 0.05mm / min, and a cutting depth of 0.2mm per layer;

[0045] First, intermittently turn the lower end face of the support plate wall, R0.78 comb cutter, spindle speed 4r / min, feed speed 0.05mm / min, each layer cutting depth 0.2mm;

[0046] Step 4: Measure the upper and lower end faces of the support plate wall using the tool tip cruise measurement method. Figure 7 As shown in the figure, take the measurement of the end face support plate wall processing surface as an example, measure the end face contour: 0.l / A / B, such as Figure 2 As shown in the figure, R0.8 offset tool is used, and the NC program is compiled to make the R0.8 offset tool tip along Fig. 9 The tool tip is 0.5 mm from the machining surface of the upper support plate wall in theoretical size. At each pause point, a 0.45 mm feeler gauge, i.e., the through end of the plug gauge, and a 0.55 mm feeler gauge, i.e., the stop end of the plug gauge, are used to measure the gap between the tool tip and the machining surface to determine whether the size is qualified. If the through end of the plug gauge cannot pass through the gap, it is determined that the part has not been machined in place, and the excess needs to be removed until it is qualified. If the through end of the plug gauge passes through the gap and the stop end of the plug gauge does not pass through the gap, it is determined to be qualified. If the stop end of the plug gauge passes through the gap, it is determined to be out of tolerance.

Claims

1. A method for intermittent processing of ultra-large thin-walled casings, characterized in that: The following steps are involved: Step 1: Clamp parts: Step 1.1, add tightening force on the left and right sides of the support plate arm by screws, and ensure that the tightening force does not cause deformation of the support plate. The tightening force can increase the overall rigidity of the support plate; Step 1.2, use an adjustable thin-walled connecting rod to connect the outer ring walls of adjacent support plates in sequence, so that all the outer ring walls of the support plates and the adjustable thin-walled connecting rod form a whole, which can increase the rigidity of the outer ring walls of the support plates and reduce the vibration during the processing of the outer ring walls of the support plates; Step 2: Polish the support plate: Manually polish the sharp edge of each support plate on the cutting side. After blunting, it can effectively reduce the impact and wear of the sharp edge on the tool, reduce the probability of tool chipping during cutting, increase tool life, and delay the decline of tool cutting performance; Step 3: Intermittent turning of the upper and lower end surfaces of the support plate wall: The tool path is consistent with the processing surface, and the processing is carried out in layers; the processing process adopts the method of cutting 2 times and finishing 1 time; the upper end surface of the support plate wall is turned intermittently first, and then the lower end surface of the support plate wall is turned intermittently; Step 4: Measure the upper and lower end surfaces of the support wall: The tool tip cruise measurement method is used for measurement, that is, the position of the tool tip is controlled by the CNC program so that the tool tip is at a certain distance from the theoretical processing surface, and then a feeler gauge is used to measure whether the surface is qualified.

2. The method for intermittently processing a super-large thin-walled casing according to claim 1, characterized in that: The adjustable thin-walled connecting rod described in step 1.2 includes connecting rod I and connecting rod II, which are connected by locking screws and nuts, and the ends of connecting rod I and connecting rod II are respectively hinged with U-shaped clamping heads, and the angles of the clamping heads are adjustable.

3. The method for intermittently processing a super-large thin-walled casing according to claim 2, characterized in that: The lower surface of the connecting rod I and the upper surface of the connecting rod II are processed into inclined surfaces, and the connecting rod I is placed on the upper part of the connecting rod II so that the inclined surfaces fit together. When the length of the adjustable thin-walled connecting rod is adjusted, the upper surface of the connecting rod I and the lower surface of the connecting rod II always remain parallel.

4. The method for intermittently processing a super-large thin-walled casing according to claim 2, characterized in that: The connecting rods I and II are provided with long holes, and locking screws pass through the long holes of the connecting rods I and II and are locked by nuts. By setting the long holes, the length of the adjustable thin-walled connecting rods can be adjusted according to the distance between adjacent support plates.

5. The method for intermittently processing a super-large thin-walled casing according to claim 1, characterized in that: In step 3, the upper end face of the support plate wall is intermittently turned using an offset tool, with a spindle speed of 3 to 5 r / min, a feed speed of 0.04 to 0.08 mm / r, and a cutting depth of 0.2 to 0.3 mm per layer.

6. The method for intermittently processing a super-large thin-walled casing according to claim 1, characterized in that: In step 3, the lower end face of the support plate wall is intermittently turned using a comb cutter, with a spindle speed of 3 to 5 r / min, a feed speed of 0.04 to 0.08 mm / r, and a cutting depth of 0.2 to 0.3 mm per layer.

7. The method for intermittently processing a super-large thin-walled casing according to claim 1, characterized in that: In step 4, the tool tip is at a certain distance from the theoretical processing surface, and the certain distance is selected to be 0.5 mm to 1 mm.

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