A high-efficiency and no joint mark diffuser blade milling method

Abstract

The application discloses a high-efficiency and no-joint-marks diffuser blade milling method, which improves the processing quality and reduces the joint marks on the blade surface. The high-efficiency and no-joint-marks diffuser blade milling method is characterized in that the profile of the blade is connected by an inner arc and an outer arc, the blade milling adopts the face milling processing, the feeding and the withdrawing positions of the blade are selected on the inner arc of the blade and are adjacent to the position of the circular arc of the inlet end of the diffuser, a tangent line which is tangent to the profile of the blade is arranged as the feeding and withdrawing path of the cutter, and the feeding and the withdrawing positions of the blade are both located on the tangent line, so that the cutter can smoothly transit when cutting into and cutting out the blade, and the direct collision between the cutter and the surface of the blade is avoided.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of superchargers, in particular to a high-efficiency and no joint knife mark diffuser blade milling method. BACKGROUND

[0002] As the core component of the supercharger, the performance of the diffuser directly affects the operation efficiency and service life of the entire supercharger. With the continuous upgrading of the quality of supercharger products, the surface quality requirements of the diffuser have also increased accordingly. This is not only a challenge to product precision, but also a severe test of processing technology. Among the many processing links of the diffuser, milling the blade is undoubtedly one of the difficulties. The shape of the diffuser is complex, the size precision requirement is high, and it also needs to have enough strength and wear resistance. Therefore, the processing of milling the blade not only requires high precision and high efficiency, but also needs to ensure the stability and reliability in the processing process.

[0003] In the milling process of the diffuser blade, the method currently adopted is: first, rough milling to remove most of the material and preliminarily form the blade shape. Then, fine milling of the blade to ensure the precision and surface quality of the blade. In the process of fine milling the diffuser blade, we currently follow a traditional tool path, that is, using the circular arc feed and retreat method from the inner arc position of the blade, and using the down milling method. The tool path method for fine milling of the blade is as follows Figure 6 .

[0004] The main reason for choosing the feed from the inner arc of the blade is that it can reduce the impact and vibration of the tool in the processing process, reduce the wear rate of the tool, and better adapt to the curved surface shape of the blade, reduce the cutting resistance in the cutting process, and improve the cutting efficiency. However, after completing the milling in this traditional feed and retreat method, the blade will often have obvious joint knife marks at the feed and retreat positions. These joint knife marks not only affect the overall aesthetics of the blade, but also have an adverse effect on the performance and service life of the blade. Therefore, a more effective tool path needs to be sought to improve this problem.

[0005] The traditional CNC program for milling the diffuser blade is as follows: the tool offset method is used for depth direction layer milling, so only the fine milling tool path needs to be drawn, and the rough milling and semi-fine milling can be increased by the tool radius milling based on the fine milling tool path.

[0006] Confirming the fine milling path step (the diffuser blades are evenly distributed, so only the fine milling path of a set of blades and flow channels needs to be found):

[0007] First step: first, draw the milling range of the tool milling one circle around the blade according to the blank size (confirm the milling range of the flow channel by confirming two blades), as follows Figure 3b, the distance of the equal distance blade in the figure = the diameter of the tool - the tool fillet, here if the direct equal distance tool diameter, then in the actual milling the bottom of the runner is left with a tool fillet part which is not milled. It can also be seen from the figure that the similar triangular runner areas on both sides are milled with a compensation tool, so the milling trajectory of the middle runner needs to be confirmed by drawing.

[0008] Second step: confirming the middle runner milling trajectory, such as Figure 4 The secondary trajectory needs to meet the condition that the blank can be milled after the tool diameter is reduced by 2 times the tool fillet, and it needs to be noted that the secondary trajectory needs to ensure that the blade cannot be milled in the case of no tool fillet, so as to prevent the blade fillet from being milled, for example: the tool diameter is 20mm, the tool fillet is 1.5mm, the tool center trajectory is equal to 8.5mm, which can mill the blank, and equal to 10mm, which cannot mill the blade.

[0009] Third step: confirming the tool feed and tool retreat trajectory, such as Figure 5 A circular arc tool feed and tool retreat position is selected at a suitable position near the blade inner arc at the end of the runner milling.

[0010] Fourth step: connecting the found trajectory points into consecutive points to form the fine milling tool trajectory, such as Figure 6 A safe tool lowering point is selected at the air outlet end, and the tool feed point, the runner milling point, the blade profile point and the tool retreat point are connected. SUMMARY

[0011] The purpose of the present application is to overcome the shortcomings of the prior art, provide a high-efficiency and no-tool mark expander blade milling method, improve the processing quality and reduce the tool mark on the surface of the blade.

[0012] The purpose of the present application is achieved as follows:

[0013] A high-efficiency and no-tool mark expander blade milling method, the profile of the blade is connected by a smooth inner arc and an outer arc, the blade milling adopts a milling process, the tool feed and tool retreat positions of the blade are selected on the inner arc of the blade and adjacent to the arc at the inlet end of the expander, a tangent line is provided as the tool feed and tool retreat path, the tool feed and tool retreat positions of the blade are located on the tangent line, so that the tool can smoothly transition when cutting into and out of the blade, and direct collision between the tool and the surface of the blade is avoided.

[0014] Preferably, the shape of the expander blade is wing-shaped.

[0015] Preferably, the method for confirming the feed and retreat positions of the blade is as follows: the feed point is selected at the inlet end of the diffuser, a straight line segment is drawn through the feed point and tangent to the circular arc of the blade inner arc, which serves as the entry and exit path of the tool, and a straight line is drawn through the right end point of the line segment and connected to the flow passage milling end point, forming an obtuse angle or a right angle. From the flow passage milling end point, the tool is milled close to the blade with left tool deflection, and after the tool has milled a circle around the blade starting from the inlet end of the blade, the tool is withdrawn in reverse from the entry and exit path of the tool and the tool deflection is ended, ending the blade milling.

[0016] The obtuse angle or right angle is set on the one hand to ensure that the tool moves along the predetermined path during cutting, thereby avoiding overcutting or undercutting and ensuring machining accuracy. On the other hand, it can to some extent reduce the impact and wear received by the tool when cutting in and out, and avoid collisions or interference between the tool and the workpiece during cutting.

[0017] Preferably, the method for milling the blade includes:

[0018] First step: rough milling

[0019] First, most of the excess of the diffuser blade is removed, and the shape of the blade is initially formed. In this process, in order to ensure the accuracy of milling, the tool radius on the machine tool is set to be 0.1-0.2mm larger than the actual tool radius, then the depth direction layering milling method is adopted, and 0.1-0.2mm of excess is left after each milling;

[0020] Reasons for improving the accuracy of milling:

[0021] 1. Compensation for processing errors: During the rough machining stage, due to factors such as tool wear, machine tool vibration, uneven workpiece material, etc., certain processing errors may occur. By reserving 0.1-0.2mm of excess, these errors can be compensated for during the finishing stage, ensuring that the final processing size meets the design requirements.

[0022] 2. Ensure surface quality: The main purpose of rough machining is to remove most of the excess, making the workpiece close to the final shape. However, the surface after rough machining is often rough, with defects such as tool marks and burrs. By reserving excess and finishing, the workpiece surface quality can be further improved, obtaining a more smooth and flat processing surface.

[0023] 3. Improve dimensional accuracy: During the finishing stage, due to the small excess, the tool cutting force is correspondingly reduced, and the machine tool vibration and deformation are also controlled. This helps to more accurately control the processing size and improve the dimensional accuracy.

[0024] 4. Prolong tool life: Reduce the cutting load and wear of the tool during the finishing stage, thereby prolonging the service life of the tool.

[0025] Second step: finish milling

[0026] Set the tool radius on the machine to the same as the actual tool and machine to depth, then follow the pre-set CNC programmed path to finish mill the blade.

[0027] Preferably, the specific rough milling step is: starting from the air outlet end of the blade, milling along the flow passage to the air inlet end of the blade, then using G41 tool offset to mill clockwise along the tool entry and exit path, completing a full circle around the blade, after completing this circle of milling, retracting in the opposite direction of the feed direction while canceling the tool offset setting, completing the rough milling of a group of blades, and then continuing the same milling operation on other blades by rotating the machine angle.

[0028] Set tool offset action: compensate tool size: due to certain size errors and wear during tool manufacturing and use, tool offset can be set to compensate for these errors, ensuring that the tool can cut according to the predetermined path and size.

[0029] Cancel tool offset action: in the entire CNC programmed path of the diffuser blade milling, the blade milling uses tool offset instructions, but the flow passage milling does not use tool offset instructions, so the tool offset needs to be canceled after milling the blade to ensure that the tool path of the subsequent flow passage milling is consistent.

[0030] In simple terms, no tool offset instructions are used when milling the flow passage, but tool offset instructions are used when milling the blade, so the tool offset needs to be canceled when retracting after milling the blade. The purpose of using tool offset when milling the blade is to avoid errors between the actual tool diameter caused by tool wear and the standard tool diameter programmed, and by setting the tool diameter or radius on the machine, this error can be compensated.

[0031] As the above technical solutions are adopted, the present application has the following beneficial effects:

[0032] This diffuser blade milling method not only improves the processing quality of the diffuser blade, but also ensures the smoothness of the blade surface and the overall performance, and improves the milling efficiency and saves production costs. This improvement helps to improve the performance of the diffuser, and also prolongs the service life of the blade. BRIEF DESCRIPTION OF DRAWINGS

[0033] Figure 1 is a diffuser structure diagram;

[0034] Figure 2 is a three-dimensional view of the diffuser;

[0035] Figure 3a diffuser milling blank;

[0036] Figure 3bTraditional milling method, tool milling around the blade milling range schematic diagram;

[0037] Figure 4 Traditional milling method, tool milling around the blade milling + flow channel milling trajectory range schematic diagram;

[0038] Figure 5 Traditional milling method, tool milling around the blade milling + flow channel milling trajectory range schematic diagram;

[0039] Figure 6 Traditional milling method, tool milling around the blade milling + flow channel milling trajectory range schematic diagram;

[0040] Figure 7 Improved milling tool trajectory;

[0041] Figure 8 Improved milling tool trajectory;

[0042] Figure 9 Rough milling blade CNC programming trajectory;

[0043] Figure 10 Rough milling blade allowance diagram;

[0044] Figure 11 The position of the feed point, flow channel milling end point schematic diagram. DETAILED DESCRIPTION

[0045] In order to improve the processing quality and reduce the blade surface joint, we optimize the fine milling tool path. Our optimization strategy focuses on the improvement of the feed and retreat position. The traditional feed and retreat method may cause friction and collision between the tool and the blade surface, leaving obvious joint marks on the blade. In order to solve this problem, we use the tangent feed and retreat method.

[0046] Specifically, at the feed and retreat position of the blade, we design a tangent line tangent to the blade profile as the tool entry and exit path. This design makes the tool smoothly transition when cutting into and out of the blade, effectively avoiding direct collision between the tool and the blade surface, thereby reducing the generation of joint marks.

[0047] When determining the feed and retreat position of fine milling, we need to fully consider the structural characteristics and processing requirements of the blade. The diffuser blade is wing-shaped, with the inner arc and outer arc connected by a smooth circular arc, which brings certain challenges to processing.

[0048] In order to meet the requirements of feeding and retreating from the inner arc and using the processing of following milling, we carefully analyze and decide to choose the best position of feeding and retreating at the position of the inner arc of the blade close to the left circular arc of the blade. Such selection is based on the following considerations:

[0049] First, using the inner arc for entry and exit ensures a smooth transition between the tool and the blade surface during entry and exit. This reduces impact and vibration during machining, lowering tool wear. It also further reduces resistance during cutting, improving cutting efficiency.

[0050] Secondly, choosing a position close to the left arc of the blade as the tool entry and exit point can make full use of the shape characteristics of the blade, making the tool more stable during the machining process.

[0051] Finally, by using tangential entry and exit, it can be ensured that the tool is tangential to the blade profile when cutting in and out, thus avoiding obvious tool marks.

[0052] In summary, selecting the optimal entry and exit positions for the tool near the left side arc of the blade's inner arc, and employing tangential entry and exit, is an efficient and high-quality finish milling solution that meets the machining requirements of diffuser blades. Figure 7 .contrast Figure 6 It is clear that the improved trajectory is significantly reduced compared to the previous one, which in turn reduces milling time and improves efficiency.

[0053] The method for confirming the entry and exit points is as follows: The entry point is selected at the diffuser inlet end, i.e., the rounded corner of the lower left corner of the blade. A straight line is drawn tangent to the rounded corner on the inner arc edge (also the inner arc). Another straight line is drawn connecting this tangent to the end point of the flow channel milling. These two lines can be obtuse or right angles, but not acute angles. From the end point of the flow channel milling, the tool is milled close to the blade using a left-side offset. After milling around the blade once from the inlet end, the tool is retracted using a straight line segment tangent to the rounded corner of the lower left corner of the blade (opposite to the entry direction). The tool offset ends at a straight line segment perpendicular to this segment, thus ending the blade milling.

[0054] The specific steps are as follows:

[0055] Step 1: Rough milling.

[0056] First, we remove most of the material using a machine tool to initially form the basic shape of the blade. During this process, to ensure milling accuracy, we deliberately set the tool radius on the machine tool to be 0.1–0.2 mm larger than the actual tool radius. Next, we use a layered milling method in the depth direction, leaving a 0.1–0.2 mm allowance after each milling pass.

[0057] The specific milling steps are: from the safe position of the blade outlet, the tool is fed along the flow channel to the inlet end of the blade. Then, in the tangential direction of the inner arc of the blade inlet corner radius, we use G41 tool offset (i.e. clockwise milling) to mill clockwise around the blade to complete a full circle of processing. After completing this circle of milling, we retreat in the opposite direction of the tool feed position in the tangential direction, and cancel the tool offset setting. Thus, the rough milling of a set of blades is completed. Subsequently, by rotating the machine angle, the same milling operation is continued on other blades, such as Figure 9 is the CNC programming trajectory for milling the diffuser. Figure 10 The residual amount of the blade after rough milling is shown, providing a basis for subsequent finishing.

[0058] Second step: finish milling.

[0059] In the stage of finishing milling the blade, our goal is to ensure that the precision and surface quality of the blade are in the best state. Therefore, on the machine tool, we set the tool radius to be exactly the same as the actual tool, and ensure that the depth direction is processed in place. Then, according to the pre-set CNC programming trajectory (the same as the rough milling Figure 9 trajectory), we perform fine milling operation on the blade. This step is crucial because it will directly affect the final precision and surface quality of the blade. Through finish milling, we can ensure that the dimensional accuracy, shape accuracy and surface roughness of the blade meet the design requirements, providing reliable protection for subsequent use.

[0060] Finally, it should be noted that the above preferred embodiments are only used to illustrate the technical solutions of the present application and are not limiting. Although the present application 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 detail without departing from the scope defined by the claims of the present application.

Claims

1. A highly efficient and seamless milling method for diffuser blades, wherein the blade profile is formed by smoothly connected inner and outer arcs, characterized in that: The blade milling adopts climb milling. The entry and exit positions of the blade are selected on the inner arc of the blade and adjacent to the arc of the diffuser inlet end. A tangent line tangent to the blade profile is set as the entry and exit path of the tool. The entry and exit positions of the blade are both located on this tangent line, so that the tool can smoothly transition when cutting into and out of the blade, avoiding direct collision between the tool and the blade surface. The method for confirming the entry and exit positions of the blade is as follows: the entry point is selected at the diffuser inlet end. Draw a straight line segment through the entry point that is tangent to the inner arc of the blade. This straight line segment serves as the entry and exit path of the tool. Draw another straight line through the right end of this straight line segment and connect it to the end point of flow channel milling. These two straight line segments form an obtuse angle or a right angle. From the end point of flow channel milling, use a left-biased tool to mill close to the blade. After the tool starts milling around the blade from the inlet end, retract the tool in the opposite direction from the entry and exit path and end the tool biasing, thus ending the blade milling.

2. The efficient and seamless milling method for diffuser blades according to claim 1, characterized in that: The diffuser blades are shaped like airfoils.

3. The efficient and tool-scar-free milling method for diffuser blades according to claim 1, characterized in that, Climb milling methods include: Step 1: Rough Milling First, most of the excess material of the diffuser blades is removed to initially form the shape of the blades. In this process, in order to ensure the accuracy of milling, the tool radius on the machine tool is set to be 0.1~0.2mm larger than the actual tool radius. Then, a layered milling method in the depth direction is adopted, and a 0.1~0.2mm allowance is left after each milling. Step 2: Precision Milling Set the tool radius on the machine tool to be the same as the actual tool and machine it to the required depth. Then, perform precision milling on the blade according to the pre-set CNC programming trajectory.

4. The efficient and seamless milling method for diffuser blades according to claim 3, characterized in that: The specific rough milling steps are as follows: start the feed from the exhaust end of the blade, mill along the flow channel to the intake end of the blade, and then use G41 tool offset to mill clockwise along the tool's feed path to complete a full circle of machining around the blade. After completing this circle of milling, retract the tool in the opposite direction of the feed direction and cancel the tool offset setting to complete the rough milling of a set of blades. Then, by rotating the machine tool angle, continue to perform the same milling operation on other blades.

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