Machining method for multi-stage air seal skewed slot of large pressure end sealing cover

Abstract

The invention discloses a machining method for a multi-stage air seal chute of a large pressure end sealing cover, which improves the machining efficiency and the machining quality of the chute. Selecting a model of a standard hard alloy blade; cutter body machining; the hard alloy blade and the cutter body are welded, and the alpha-angle welding type special cutter is obtained; the straight wall end of a to-be-machined chute of a workpiece blank is taken as an extension line, a vertical line is taken at the inflection point of the inclined wall end of the chute towards the extension line, the extension line and the vertical line are connected to form a boundary line, the boundary line and the outer chute wall of the to-be-machined chute define an area A, the boundary line and the inner chute wall of the to-be-machined chute define an area B, the area A is an axial machining area, and the area B is an axial machining area. The area B is an inclined machining area; selecting an end face ring groove cutter; according to the divided machining areas, the selected standard end face ring groove cutter and the manufactured alpha-angle welding type special cutter, overall machining programming of a workpiece chute is completed, and a feeding method of symmetry from the middle to the two sides is adopted for a single area; and turning the workpiece.

Description

Technical Field

[0001] The present invention relates to the field of metal cutting technology, and in particular to a method for machining a multi-stage gas seal bevel groove of a large pressure end sealing cover, providing a new tool structure design scheme and a turning method for turning a multi-stage gas seal bevel groove of a large pressure end sealing cover in a large flow supercharger product. Background Art

[0002] With the continuous breakthroughs in the research, development, design and manufacturing of large-flow supercharger products, some large-size parts have problems in the processing of traditional turning methods. Among them, the processing performance of the pressure end sealing cover parts with multi-stage gas sealing grooves is the most prominent. The shape and structure of the pressure end sealing cover are as follows: Figure 1 , Figure 2 As shown in the figure, the material of the part is ductile iron, and the overall shape is thin-walled disc. The maximum outer diameter of the traditional pressure end sealing cover ranges from 400 to 600 mm. In actual production, the multi-stage sealing chute of this type of pressure end sealing cover is mostly processed by a three-claw light clamping outer circle combined with an integrated hand-grinding forming tool turning method. The structure of the integrated hand-grinding forming tool is as follows Figure 3 As shown in the figure, the traditional turning method is as follows Figure 4 As shown in the figure, the blank in the bevel groove is turned by an integrated hand-ground forming tool through three tool paths 1, 2, and 3 in sequence. The problems existing in this processing method in the past in the processing of parts with smaller overall structures are relatively not obvious. The corresponding bevel size of the parts with smaller structures is shallow, the overall thickness of the blank is small, the overall path required for the tool to complete the overall turning is short, and the cutting edge is involved in the removal of less blanks. In the batch processing of parts, the performance of traditional hand-ground tools can barely meet the basic production and processing of parts. However, with the continuous improvement of customer demand for product flow, the specifications and dimensions of the pressure end sealing cover adapted to the large flow supercharger have increased by leaps and bounds compared with the past. Especially in the processing of the current large-size pressure end sealing cover with a diameter of 800-1000mm, traditional tools and processing methods will have a variety of problems when turning the deep and thick blanks in the multi-stage sealing bevel groove. The specific problems are mainly manifested in the following four aspects:

[0003] 1. Customized tools are expensive and take a long time

[0004] The multi-stage air-sealing bevel grooves of large pressure-end sealing cover parts of different models have large differences in angle and width from the specifications of conventional standard tools according to the use requirements. Only special forming tools customized according to the specific specifications and angles of the bevel grooves of the parts can meet the processing requirements. However, customized tools are expensive and have a long delivery cycle, and cannot meet the daily efficient processing needs of parts.

[0005] 2. Traditional hand-sharpened knives have a short lifespan and are prone to breaking.

[0006] Taking into account the defects of expensive and time-consuming customized tools, this type of multi-stage sealing bevel groove of the pressure end sealing cover is still processed by hand-ground one-piece high-speed steel tools in traditional turning. However, the hand-ground tools are affected by the material properties of the tools themselves in actual applications, and the tool edge strength and wear resistance in the actual turning process are particularly insufficient. Especially in the current batch processing of large-scale pressure end sealing cover multi-stage air seal bevel groove parts, the excessive depth and thickness of the blanks cause the tool edge to wear too quickly, and in severe cases, the tool head may break. The existence of these problems makes it difficult to guarantee the quality and efficiency of parts in daily processing.

[0007] 3. The turning force of parts is unstable, easy to loosen, and the processing efficiency and qualified rate are low.

[0008] The large-scale pressure end sealing cover with a diameter of 800-1000mm is a thin-walled part in structure, such as Figure 1 , Figure 2 As shown in the figure, thin-walled parts require a smaller clamping force to clamp them during processing. Excessive clamping force will cause the parts to deform. The force on the parts during the processing of traditional conventional one-piece hand-grinding forming tools will increase rapidly with the rapid wear of the tool edge, especially at the moment of edge collapse and tool head breakage. Excessive force and instantaneous stress mutation will cause the parts to become loose. The looseness of the parts will greatly reduce the processing efficiency of the parts, and in severe cases, it will cause the parts to be scrapped.

[0009] 4. Repeated sharpening of the tool leads to low processing efficiency

[0010] Due to the short service life of traditional hand-ground forming knives, workers need to repeatedly sharpen the cutting edge of the tool during the actual processing process. The sharpened tool also needs to be realigned when it is used again. These repetitive tasks reduce the processing efficiency of parts to a certain extent. Summary of the invention

[0011] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a method for processing a multi-stage gas sealing chute of a large pressure end sealing cover, thereby improving the processing efficiency and the processing quality of the chute.

[0012] The object of the present invention is achieved in that:

[0013] A method for processing multi-stage gas sealing chute of a large pressure end sealing cover,

[0014] Step 1: Selection of standard carbide inserts

[0015] According to the width W of the workpiece bevel groove, select a standard square grooving carbide blade with a width less than W. Suppose the width of the selected standard blade is w1, w1<W;

[0016] Step 2: Cutter body processing

[0017] The cutter body shape is processed according to the cutter body clamping structure of the machine tool, and then according to the bevel angle α of the workpiece, a U-shaped keyway with the same inclination angle is milled at the cutter head position of the cutter body, and the width of the U-shaped keyway is greater than the width w1 of the selected blade;

[0018] Step 3: Tool welding

[0019] The carbide blade is placed symmetrically in the U-shaped keyway along the α angle and welded. After welding, the blade edge is kept level with the upper surface of the blade body to obtain an α-angle welded special blade.

[0020] Step 4: Divide the processing area of ​​the workpiece

[0021] An extension line is drawn at the straight wall end of the oblique groove to be processed of the workpiece blank, and a vertical line is drawn toward the extension line at the turning point of the oblique wall end of the oblique groove. The extension line and the vertical line are connected to form a boundary line. The boundary line and the outer groove wall of the oblique groove to be processed enclose an area A, and the boundary line and the inner groove wall of the oblique groove to be processed enclose an area B, wherein the area A is an axial processing area, and the area B is an oblique processing area;

[0022] Step 5: Face Groove Tool Selection

[0023] Assume the length of the vertical line is w2, select a standard end face ring groove cutter with a width less than w2, and the width of the standard end face ring groove cutter is w3<w2;

[0024] Step 6: Programming

[0025] According to the divided processing areas, the selected standard end face ring groove cutter, and the manufactured α-angle welding special cutter, the overall processing program of the workpiece bevel groove is compiled, and a single area adopts a symmetrical cutting method from the middle to both sides;

[0026] Step 7: Workpiece turning

[0027] Use a standard face ring groove cutter to rough turn the A area of ​​each ring groove of the workpiece blank along the axial direction;

[0028] Use a special welding tool with an α angle to rough turn the B area of ​​each ring groove of the workpiece blank along the α angle;

[0029] Use standard face ring groove cutter to finish turn the side of the bevel groove in area A of each ring groove;

[0030] Use a special α-angle welding tool to finish turn the bevel groove side of each ring groove B area.

[0031] Preferably, 45 steel material is selected, and the cutter body shape is processed by wire cutting or milling.

[0032] Preferably, the depth of the U-shaped keyway is h, the thickness of the selected cemented carbide blade is h1, h≥h1, and a copper gasket of corresponding thickness is added to the bottom of the keyway before welding to ensure that the blade edge remains level with the upper surface of the blade body after welding.

[0033] Due to the adoption of the above technical solution, the specific beneficial effects of the new α-angle welding special tool designed for turning the multi-stage gas seal bevel groove of the large pressure end sealing cover and the turning tool path method compared with the traditional processing are mainly reflected in the following aspects:

[0034] 1. High-performance, low-cost, efficient and convenient special tool design method

[0035] The α-angle welded special tool designed for the multi-level bevel groove of the large-scale pressure end sealing cover of the present invention can achieve efficient production according to the width and angle of the bevel groove of parts of different specifications. The production method is simple and fast. At the same time, the tool has the excellent performance of customized tools and the low cost characteristics of traditional integrated hand-sharpened tools. While ensuring low production costs, the excellent performance of the carbide blade meets the stable processing of large-volume parts turning.

[0036] 2. The turning accuracy and stability of multi-stage inclined grooves are greatly improved

[0037] The present invention provides a method for controlling the intersection zoning and high-precision program feeding of turning forces for thin-walled parts with multi-stage air-sealing bevel grooves such as large pressure end sealing covers, which transforms the traditional one-piece turning forming method into a high-speed feeding method with a small amount of multi-stage stratification for axial and oblique forming, effectively controls the influence of radial stress on part processing, greatly reduces the mutual force between the tool and the part during cutting, effectively controls the deformation of the part processing, and at the same time, the bevel processing accuracy and surface quality are well guaranteed.

[0038] 3. Product processing efficiency is improved, and the quality of chute processing is highly stable

[0039] The present invention effectively avoids the problems of tool breakage, part loosening, repeated alignment, etc. that exist in the traditional one-piece hand-grinded forming turning tool processing of the multi-stage air seal bevel groove of the large pressure end sealing cover by changing the tool and the turning method. The problem of part clamping loosening caused by traditional turning radial stress no longer occurs, and the stability of product processing quality is guaranteed. The new processing tool and turning method no longer have the problems of frequent tool breakage and grinding during mass production application, and the part processing efficiency and stability are improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 This is a schematic diagram of a large pressure end sealing cover;

[0041] Figure 2 It is a schematic diagram of a multi-stage gas seal chute;

[0042] Figure 3 This is a schematic diagram of a traditional one-piece molded hand-sharpened turning tool;

[0043] Figure 4 It is a schematic diagram of the traditional turning cutting method;

[0044] Figure 5 It is a schematic diagram of the knife body;

[0045] Figure 6 This is a schematic diagram of a special knife for α-angle welding;

[0046] Figure 7 This is a schematic diagram of the tool path for axial turning with a standard face ring groove cutter;

[0047] Figure 8 This is a schematic diagram of the oblique tool path of the α-angle welding special tool;

[0048] Fig. 9 Schematic diagram of stress distribution in traditional turning process. DETAILED DESCRIPTION

[0049] The present invention aims to solve the problems of expensive customized tools, low durability of hand-ground tools, easy breakage of tool heads, loosening and instability of parts during turning, and difficulty in ensuring dimensional accuracy and processing efficiency in traditional turning of multi-stage air-sealing chute of large pressure-end sealing cover. The present invention conducts in-depth analysis of the structural characteristics of thin-walled parts of large pressure-end sealing cover and the defects of traditional tools and processing methods for multi-stage chute. By changing the tool material and design structure, the tool durability is improved, the tool service life is extended, the tool cost is reduced, and the convenience of tool manufacturing is improved. By changing the turning tool feeding method, the turning force direction is controlled, the influence of radial turning stress on part processing stability is reduced, and the batch production efficiency of products is improved. The present invention provides a new α-angle welded special tool structure designed for turning multi-stage air-sealing chute of large pressure-end sealing cover. Figure 6 As shown in the figure, the new turning method is as follows Figure 7 , Figure 8 As shown, the specific composition and principle are as follows:

[0050] Tool composition:

[0051] The tool designed for the multi-stage gas seal inclined groove structure of the large pressure end sealing cover of the present invention is mainly composed of a carbide blade and a 45 steel tool body welded at a specific angle α of the part inclined groove, wherein the U-shaped keyway (such as Figure 5The carbide insert (as shown) plays the role of guiding and positioning when welding. The different angles and widths of the bevel grooves of different large-scale pressure end sealing cover parts correspond to different tool specifications. When different specifications of tools are welded and formed, the width w1 of the selected carbide insert should be smaller than the width W of the bevel groove processed by the tool (Note: The width of the traditional one-piece forming hand-grinded turning tool is equal to the width of the corresponding turning bevel groove).

[0052] Principle of the invention:

[0053] The first step is to reduce the contact area between the tool and the part by reducing the width of the tool edge, thereby achieving the purpose of reducing the turning stress. After the oblique turning stress is reduced, the corresponding radial stress will also be reduced, and the stability of the part light clamp turning will be improved accordingly; the second step is to replace the blade material involved in the cutting position with cemented carbide, which can greatly improve the overall cutting performance of the tool, ensure the ultra-long processing life of the tool, and avoid excessive wear or collapse of the tool edge; the third step is to replace the tool body material with the cheaper 45 steel, which not only ensures the functionality of the final formed tool, but also further reduces the overall production cost of the tool; the fourth step, the U-shaped keyway structure size with flexible and variable position of the tool head ensures the convenience and efficiency of the production of special tools for multi-stage gas seal bevel grooves of large pressure end sealing covers of different models. It is only necessary to adjust the angle and width of the U-shaped keyway milled by the tool head according to the angle and width of the bevel groove, and then complete the blade welding to quickly and efficiently obtain special tools for bevel groove processing of parts of corresponding specifications.

[0054] Turning method:

[0055] Aiming at the structural characteristics and processing stress characteristics of the multi-stage gas seal inclined groove of the large pressure end sealing cover parts, the present invention transforms the traditional one-piece molding hand-grinding single oblique feed turning processing method into a regional two-side feed processing method. Figure 7 The intersection partitioning method shown in the figure divides the integral blank for traditional internal turning of the inclined groove into two areas: axial and oblique processing. A single area adopts a symmetrical tool path from the middle to both sides to complete the rough and fine turning of the inclined groove. The specific tool path method and processing sequence are as follows: Figure 7 , Figure 8 shown.

[0056] Principle of the invention:

[0057] The core of the new turning method provided by the present invention for the multi-stage gas sealing inclined groove of the large pressure end sealing cover part is to control the turning stress. In the processing of the traditional single inclined cutting method, the part is continuously affected by the oblique stress generated by the tool during cutting. The component force F1 of the oblique stress F in the radial direction of the part continuously counteracts the light clamping stress of the part. The specific state is as follows: Fig. 9As shown, especially in the continuous turning process of the large excess blank inside the entire chute, the wide traditional turning tool, fast edge wear, edge collapse and other factors are the root causes of the large radial force and instability of turning. As a thin-walled part, when the small light clamping stress of the large pressure end sealing cover is not enough to counteract the radial force generated during turning, the part will become loose, resulting in product processing scrap, repeated clamping, reduced efficiency and other problems. In response to such a situation, this invention changes the traditional single oblique turning processing method and converts the integral blank inside the chute into a Figure 7 The intersection partitioning method shown is divided into two areas, axial and oblique, for distributed processing. More than 70% of the blanks in the axial partition of the bevel groove are turned by the axial feed method, and a small number of blanks in the oblique partition are turned by the α-angle welding special tool with a smaller width newly designed by the present invention through the oblique feed method on both sides. Through these two-step measures, the radial stress generated by the tool turning inside the bevel groove is greatly reduced. In particular, when turning in the axial partition, the tool feed direction is always consistent with the Fig. 9 The axial force F2 shown remains consistent, and the radial force generated by the tool in the turning process is small enough to be ignored. The remaining small amount of blanks in the remaining oblique partition are turned with the α-angle welded special tool with a smaller width provided by the present invention. Compared with the original turning method, the new turning method not only greatly reduces the turning time of the oblique stress condition, but the stress itself also becomes smaller with the application of the new structure tool and the tool feeding method of the present invention. Therefore, the turning method and tool provided by this invention for the multi-stage air seal bevel groove of the large pressure end sealing cover part realize the effective control of the part processing stress, and the processing quality, efficiency, stability, and cost of the multi-stage air seal bevel groove of the part are effectively controlled.

[0058] The implementation of the present invention is mainly divided into the following seven steps, and the detailed implementation steps are as follows: Figure 1 , Figure 2 Take the inclined groove processing of a large pressure end sealing cover part as an example, the specific contents are as follows:

[0059] Step 1: Selection of standard carbide inserts

[0060] according to Figure 2 The structure shape and width of the multi-stage gas seal inclined groove of the large pressure end sealing cover part shown in the figure are as follows. A standard square grooving carbide blade with a width less than W is selected. Assuming that the selected standard blade width size is w1, w1<W, the measurement position of the blade width w1 is as follows Figure 6 shown.

[0061] Step 2: Cutter body processing

[0062] According to the structural dimensions and appearance of the conventional clamping tool body of the machine tool selected for part processing, 45 steel material is selected for processing. Figure 5The cutter body shape shown in the figure can be processed by wire cutting or milling. After the cutter body shape processing is completed, the cutter head position of the cutter body is milled according to the specific α angle of the multi-stage gas seal inclined groove of the large pressure end sealing cover part to be processed. Figure 5 The U-shaped keyway with the same angle as shown in the figure is mainly used to guide and position the subsequent welding of the carbide blade. The width of the U-shaped keyway should be slightly larger than the width w1 of the selected blade. The uniform gap width between the blade and the side of the keyway should not exceed 0.5mm. Assuming the depth of the U-shaped keyway is h, the thickness of the selected blade is h1. Figure 6 As shown, the depth of the U-shaped keyway should be greater than or equal to the selected blade thickness, that is, h ≥ h1, and the maximum error between h and h1 should not exceed 0.5 mm.

[0063] Step 3: Tool welding

[0064] After the tool body is processed, the carbide blade selected in the first step is placed symmetrically along the α angle in the U-shaped keyway and welded by copper welding or silver copper welding. It should be noted that the slight gap between the blade and the side of the U-shaped keyway should be kept as uniform as possible when using copper welding or silver copper welding. The center height of the tool edge after welding can be adjusted by adding a copper gasket of appropriate thickness at the bottom of the keyway before welding to ensure that the blade edge is level with the upper surface of the tool body after welding. The above steps can be used to obtain Figure 6 The α-angle welded special tool shown is suitable for processing the bevel groove of specific parts.

[0065] Step 4: Intersection Partitioning

[0066] According to the invention, a new partitioning and turning method is involved. Figure 1 , Figure 2 Taking the processing of a certain type of large-scale pressure end sealing cover multi-level inclined groove as an example, according to the special structural characteristics of the inclined groove, the blank to be processed in the inclined groove is Figure 7 In the method shown, the intersection is divided into two areas A and B as the boundary, where area A is the axial processing area and area B is the oblique processing area.

[0067] Step 5: Face Groove Tool Selection

[0068] According to the specific size of the bottom width w2 of the axial processing area A, a standard machine clamp end face ring groove cutting tool with a width less than w2 is selected. The outer structural dimensions of the tool body are selected based on the inner and outer diameter size range of the multi-stage bevel groove belt of the large pressure end sealing cover being processed. The standard grooving tool width w3<w2.

[0069] Step 6: Programming

[0070] According to the clear processing area, the grooving cutter with corresponding structure and width is selected to complete the overall compilation of the multi-level chute program of the large pressure end sealing cover. Figure 1 , Figure 2 Taking the processing of a certain type of large-scale pressure end sealing cover multi-level inclined groove as an example, the specific program compilation can be divided into the following two steps:

[0071] 1. Select the end face ring groove cutter specified in step 5. Figure 7 The tool path method and path shown in the figure complete the programming of the axial partition A area, where the 1st, 2nd, 3rd, 4th, 5th, 6th and 7th tool paths are for rough turning, and 8th and 9th are for fine turning;

[0072] 2. Select the α angle welding special knife made in the third step. Figure 8 The tool path method and path shown in the figure complete the programming of the oblique partition B area, where the first tool path is for rough turning, and 2 and 3 are for fine turning;

[0073] Step 7: Part Turning

[0074] The actual turning of the multi-stage inclined groove of the large pressure end sealing cover is mainly divided into the following four steps:

[0075] Use standard end face ring groove cutter to rough turn the axial blank of each ring groove A area, such as Figure 7 As shown, the specific turning method and tool path refer to the 1st to 7th tool paths in the figure, and a finishing allowance of 0.05-0.15mm is reserved on the side of the inclined groove;

[0076] Use α angle welding special cutter to rough turn the oblique blank in each ring groove B area, such as Figure 8 As shown in the figure, the specific turning method and tool path refer to the first tool path in the figure, and a finishing allowance of 0.05-0.1mm is reserved on the side of the inclined groove;

[0077] Use standard end face ring groove cutter to finish turn the side of the bevel groove of each ring groove A area, leaving 0.05-0.15mm of blank, such as Figure 7 As shown, the specific turning method and tool path refer to the 8th and 9th tool paths in the figure, and the side of the inclined groove is processed in place;

[0078] Use α angle welding special tool to fine turn the side of the bevel groove of each ring groove B area to leave 0.05-0.1mm blank, such as Figure 8 As shown, the specific turning method and tool path refer to the 2nd and 3rd tool paths in the figure, and the side of the inclined groove is processed in place;

[0079] The above seven steps can realize high-quality, high-efficiency and stable processing of multi-stage air-sealing bevel grooves of large-scale pressure-end sealing covers. The α-angle welding special tool designed in this invention can be repeatedly sharpened like traditional hand-sharpened tools after processing large quantities of parts, so the tool cost, processing quality and processing efficiency are all guaranteed.

[0080] Finally, it should be noted that the above preferred embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail through the above preferred embodiments, those skilled in the art should understand that various changes can be made in form and details without departing from the scope defined by the claims of the present invention.

Claims

1. A method for processing a multi-stage gas sealing chute of a large pressure end sealing cover, characterized in that: Step 1: Selection of standard carbide inserts According to the width W of the workpiece bevel groove, select a standard square grooving carbide blade with a width less than W. Suppose the width of the selected standard blade is w1, w1<W; Step 2: Cutter body processing The cutter body shape is processed according to the cutter body clamping structure of the machine tool, and then according to the bevel angle α of the workpiece, a U-shaped keyway with the same inclination angle is milled at the cutter head position of the cutter body, and the width of the U-shaped keyway is greater than the width w1 of the selected blade; Step 3: Tool welding The carbide blade is placed symmetrically in the U-shaped keyway along the α angle and welded. After welding, the blade edge is kept level with the upper surface of the blade body to obtain an α-angle welded special blade. Step 4: Divide the processing area of ​​the workpiece An extension line is drawn at the straight wall end of the oblique groove to be processed of the workpiece blank, and a vertical line is drawn toward the extension line at the turning point of the oblique wall end of the oblique groove. The extension line and the vertical line are connected to form a boundary line. The boundary line and the outer groove wall of the oblique groove to be processed enclose an area A, and the boundary line and the inner groove wall of the oblique groove to be processed enclose an area B, wherein the area A is an axial processing area, and the area B is an oblique processing area; Step 5: Face Groove Tool Selection Assume the length of the vertical line is w2, select a standard end face ring groove cutter with a width less than w2, and the width of the standard end face ring groove cutter is w3<w2; Step 6: Programming According to the divided processing areas, the selected standard end face ring groove cutter, and the manufactured α-angle welding special cutter, the overall processing program of the workpiece bevel groove is compiled, and a single area adopts a symmetrical cutting method from the middle to both sides; Step 7: Workpiece turning Use a standard face ring groove cutter to rough turn the A area of ​​each ring groove of the workpiece blank along the axial direction; Use a special welding tool with an α angle to rough turn the B area of ​​each ring groove of the workpiece blank along the α angle; Use standard face ring groove cutter to finish turn the side of the bevel groove in area A of each ring groove; Use a special α-angle welding tool to finish turn the bevel groove side of each ring groove B area.

2. The method for processing a multi-stage gas sealing chute of a large-scale pressure end sealing cover according to claim 1, characterized in that: Select 45 steel material and process the cutter body shape through wire cutting or milling.

3. The method for processing a multi-stage gas sealing chute of a large-scale pressure end sealing cover according to claim 1, characterized in that: Assume that the depth of the U-shaped keyway is h, the thickness of the selected carbide blade is h1, h≥h1, and add a copper gasket of corresponding thickness at the bottom of the keyway before welding to ensure that the blade edge remains level with the upper surface of the tool body after welding.

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