Weak-rigidity workpiece symmetrical segmentation alternate machining method and machining device

Abstract

The invention provides a symmetric segmented alternate machining method and device for a weak-rigidity workpiece. The machining method comprises the following steps that the two ends, in the length direction, of the weak-rigidity workpiece are clamped and fixed; a milling cutter is driven to machine a groove in the middle line position of the weak-rigidity workpiece in the length direction; determining the critical symmetric segment size; the area on one side of the groove is divided into a plurality of first machining areas, the area on the other side of the groove is divided into a plurality of second machining areas, and the width of the first machining areas and the width of the second machining areas are both not larger than the critical symmetric segment size; and a plurality of first machining areas and a plurality of second machining areas are sequentially machined in the direction from the groove to the two ends of the weak-rigidity workpiece, and machining of the first machining areas and machining of the second machining areas are alternately carried out. The problems of machining deformation and chatter generated in the machining process of the weak-rigidity workpiece can be solved, and the machining efficiency and machining quality of the weak-rigidity workpiece are greatly improved.

Description

Technical Field

[0001] The present invention relates to the technical field of numerical control machining, and more specifically to a symmetrical segmented alternating machining method and a machining device for a weak rigidity workpiece. Background Art

[0002] Weakly rigid workpieces have many advantages such as light weight and have been widely used in many fields such as aerospace. For example, aircraft engine blades, missile wings, and marine propellers are typical weakly rigid workpieces. These workpieces have thin walls, large machining allowances, and complex structures. During the machining process, they are prone to problems such as machining deformation and flutter, which seriously restricts their machining efficiency and quality.

[0003] At present, there are two main processing methods for the processing of such weak rigid parts. One is the single-end cantilever processing method similar to the integral blade of an aero-engine. Such parts generally cannot be clamped at both ends and can only be processed by a single-end cantilever processing method under auxiliary support. The processing order is from the tip of the blade to the root of the blade. The workpiece processed in this way has large deformation and flutter, and the processing efficiency is low. The document "A method and device for reverse segmentation processing of weak rigid workpieces" CN104889706A proposes a reverse segmentation processing method for single-end cantilever processing of weak rigid parts, that is, contrary to the traditional processing method, the workpiece is processed from the fixed end to the free end. This method can solve the deformation and flutter problems in the processing of weak rigid parts to a certain extent, but this method requires the processed part to be fixed or auxiliary supported to enhance its rigidity before processing the next section. The processing process is relatively cumbersome and the processing efficiency is low, which is not suitable for efficient automated processing.

[0004] The other is the double-end clamping processing method. This processing method can enhance the rigidity of the process system to a certain extent compared with the single-end clamping processing method. However, the processing of long weak rigid parts also has the problem of low processing efficiency due to chattering, especially when processing the middle part of the workpiece where the rigidity is the weakest. The chattering and deformation problems are more prominent, making it impossible to use high-speed feed for workpiece cutting, which restricts the processing efficiency of the entire workpiece. Some literature proposes to use auxiliary support to enhance the rigidity of the process system, that is, to use a multi-point auxiliary support method to reduce the processing deformation and vibration of thin-walled parts. However, the auxiliary support method can only process the opposite side of the support position during the processing process, and needs to be turned over and installed again after processing. This method takes a long time to assist, is cumbersome to operate, has low processing efficiency, and is difficult to achieve efficient automated processing. Summary of the invention

[0005] 1. Technical issues to be resolved

[0006] The technical problem to be solved by the present invention is that the existing processing methods have the problems that the workpiece is prone to vibration and deformation, the auxiliary time is long, the process is cumbersome, and it is difficult to achieve efficient and automated processing.

[0007] (II) Technical solution

[0008] To achieve the above object, the technical solution adopted by the present invention is:

[0009] In a first aspect, the present invention provides a method for symmetrically segmenting and alternatingly processing a weakly rigid workpiece, comprising the following steps:

[0010] Clamp and fix the two ends of the weak rigid workpiece along the length direction;

[0011] The milling cutter is driven to machine a groove at a midline position in the length direction of the weak rigidity workpiece;

[0012] Determine a critical symmetric segment size within which a weakly rigid workpiece can meet machining deformation requirements under a chatter-free cutting parameter condition;

[0013] Dividing an area on one side of the groove into a plurality of first processing areas, and dividing an area on the other side of the groove into a plurality of second processing areas, wherein the width of each of the first processing area and the second processing area is not greater than the critical symmetric segment size;

[0014] A plurality of the first processing areas and a plurality of the second processing areas are processed in sequence along the groove toward both ends of the weakly rigid workpiece, wherein the processing of the plurality of the first processing areas and the processing of the plurality of the second processing areas are performed alternately.

[0015] Preferably, the weakly rigid workpiece has a first end and a second end along the width direction, and in multiple first processing areas, the milling cutter feeds from the first end to the second end, and in multiple second processing areas, the milling cutter feeds from the second end to the first end.

[0016] Preferably, the milling cutter rotates in a clockwise direction during processing of the first processing area and the second processing area.

[0017] Preferably, the milling cutter rotates in a counterclockwise direction during processing of the first processing area and the second processing area.

[0018] Preferably, the milling cutter is fed along a helical trajectory during the process of machining the first machining area and the second machining area.

[0019] Preferably, when machining the groove, the milling cutter performs machining in layers from top to bottom.

[0020] In the second aspect, the present invention also provides a processing device for implementing the symmetrical segmented alternating processing method of a weakly rigid workpiece described in any one of the above-mentioned technical solutions, comprising a CNC milling machine and a clamping tool, wherein the clamping tool is used to clamp and fix the two ends of the weakly rigid workpiece along the length direction, and the CNC milling machine comprises a milling cutter and a multi-axis motion assembly, wherein the milling cutter is connected to the multi-axis motion assembly, and the milling cutter is used to process the weakly rigid workpiece, and the multi-axis motion assembly is used to drive the milling cutter to move along a preset trajectory.

[0021] Preferably, the CNC milling machine is a five-axis machine tool.

[0022] (III) Beneficial effects

[0023] The above technical solution of the present invention has at least the following advantages:

[0024] 1. In the present invention, a groove is processed at the midline position in the length direction of the weak rigid workpiece, and the groove can be used to release the stress generated by the processing in the subsequent processing process; the two sides of the weak rigid workpiece are symmetrically segmented into multiple first processing areas and multiple second processing areas with the groove as the axis, and then the multiple first processing areas and multiple second processing areas are processed in sequence by an alternating processing method, which can basically eliminate the processing deformation and chatter problems caused by insufficient rigidity of the process system in the processing method of the prior art, and greatly improve the processing efficiency and processing quality of the weak rigid workpiece.

[0025] 2. In the present invention, the symmetrical segmented alternating processing method of the weak rigid workpiece provided by the present invention does not require auxiliary support installation for the processed area, and can complete the processing of the entire weak rigid workpiece after the weak rigid workpiece is installed once. It has high efficiency, small vibration, short processing auxiliary time, and is suitable for efficient automated processing and production.

[0026] 3. In the present invention, the symmetrical segmented alternating processing method for weak rigidity workpieces provided by the present invention can always keep the rigidity of the process system of the weak rigidity workpiece in the strongest state when processing the current area, thereby ensuring the processing efficiency and precision of the workpiece. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0028] Figure 1 It is a schematic flow chart of a method for symmetrically segmented alternating processing of a weakly rigid workpiece provided by an embodiment of the present invention.

[0029] Figure 2It is a schematic diagram of the arrangement positions of the grooves, the first processing area and the second processing area provided in an embodiment of the present invention.

[0030] Figure 3 It is the feeding direction of the milling cutter in the first processing area provided by the embodiment of the present invention.

[0031] Figure 4 It is the feeding direction of the milling cutter in the second processing area provided by the embodiment of the present invention.

[0032] The reference numerals in the figures are:

[0033] 1. First clamping member; 2. Weakly rigid workpiece; 3. Second clamping member; C. Groove. DETAILED DESCRIPTION

[0034] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0035] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it may be directly located on the other element or indirectly located on the other element. When an element is referred to as being "connected to" another element, it may be directly connected to the other element or indirectly connected to the other element.

[0036] It should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" etc., indicating directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings and are only for the convenience of describing the present invention, and do not indicate that a device or element must have a specific direction, be constructed and operated in a specific direction, and therefore should not be understood as a limitation on the present invention.

[0037] In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating relative importance or indicating the number of technical features. In the description of the present invention, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined. The specific implementation of the present invention is described in more detail below in conjunction with specific embodiments:

[0038] like Figure 1 and Figure 2 As shown, an embodiment of the present invention provides a method for symmetrically segmenting and alternatingly processing a weakly rigid workpiece, comprising the following steps:

[0039] S1. Clamp and fix the two ends of the weak rigid workpiece 2 along the length direction; specifically, taking the AB five-axis machine tool as an example, the weak rigid workpiece is clamped at both ends of the length direction with a clamp, and then the clamp is installed on the A-axis at the left and right ends of the machine tool, so as to realize the double-end clamping and installation of the workpiece.

[0040] S2, drive the milling cutter to process groove C at the midline position of the length direction of the weak rigid workpiece 2; for weak rigid workpieces with large cutting allowances, if cutting starts from the middle, it will be processed directly in one layer. At this time, the cutting depth and width of the tool are large, which is easy to cause deformation and chatter. Therefore, before processing the first processing area and the second processing area, in order to avoid the chatter and deformation problems caused by the first tool processing, it is necessary to first process a stress-releasing groove C at the middle position where the rigidity of the weak rigid workpiece is weakest. At the same time, in order to ensure the surface quality of the weak rigid workpiece and avoid chatter, the processing of groove C can be divided into multiple layers of cutting, and the processing of groove C does not need to be processed to the design size of the workpiece, and a partial allowance can be set to be removed in subsequent processing.

[0041] S3. Determine the critical symmetrical segment size, within which the weak rigid workpiece 2 can meet the machining deformation requirements under the condition of chatter-free cutting parameters; specifically, determine the critical symmetrical segment size of the weak rigid workpiece 2 that meets the machining deformation requirements under the condition of chatter-free cutting parameters through experiments, and the critical symmetrical segment size can be used as the length limit of the workpiece segment.

[0042] S4, dividing the area on one side of the groove C into a plurality of first processing areas (such as Figure 2 A1, A2, A3, A4) shown in the figure, the area on the other side of the groove is divided into a plurality of second processing areas (such as Figure 2 B1, B2, B3, B4) as shown, wherein the width of the first processing area and the second processing area are not greater than the critical symmetrical segment size; wherein the actual segment length of the first processing area and the second processing area can be less than the critical symmetrical segment size.

[0043] S5. Process multiple first processing areas and multiple second processing areas in sequence along the groove toward the two ends of the weak rigid workpiece 2. In the process of processing the weak rigid workpiece 2, the rigidity of the middle area of ​​the weak rigid workpiece 2 is the weakest. Therefore, the weak rigid workpiece is processed in sequence along the groove toward the two ends of the weak rigid workpiece 2, which can ensure that the rigidity of the process system is in the strongest state during the entire processing process, wherein the processing of multiple first processing areas and the processing of multiple second processing areas are performed alternately. Specifically, the cutter is cut from the groove C where the weak rigid workpiece 2 has been processed, and the workpiece is processed from the middle part where the rigidity is weakest to both ends in an alternating left-right manner or a right-left alternating manner according to the number of first processing areas and second processing areas that have been divided on the weak rigid workpiece 2. Among them, the processing method is spiral processing, and considering the processing vibration caused by forward milling and reverse milling, the same milling method is used in the processing process of the left and right ends, both of which are reverse milling or both are forward milling.

[0044] Finally, after the above processing is completed, if the weak rigid workpiece has been processed to the designed size of the workpiece, the processing is completed and the workpiece is disassembled.

[0045] In one embodiment, if Figure 3 As shown, the weak rigid workpiece 2 has a first end and a second end along the width direction. In a plurality of first processing areas, the milling cutter feeds from the first end to the second end. Figure 4 As shown, in a plurality of second processing areas, the milling cutter is fed from the second end toward the first end.

[0046] In one embodiment, the milling cutter rotates in a clockwise direction during machining of the first machining area and the second machining area, that is, the milling cutter mills forward.

[0047] In one embodiment, the milling cutter rotates in a counterclockwise direction during machining of the first machining area and the second machining area, that is, the milling cutter performs reverse milling.

[0048] In one of the embodiments, the milling cutter is fed along a helical trajectory during machining of the first machining area and the second machining area.

[0049] In one embodiment, when machining the groove, the milling cutter performs machining in multiple layers from top to bottom.

[0050] An embodiment of the present invention also provides a processing device for implementing the symmetrical segmented alternating processing method of a weakly rigid workpiece according to any one of the above-mentioned embodiments, comprising a CNC milling machine and a clamping tool, the clamping tool being used to clamp and fix the two ends of the weakly rigid workpiece along the length direction. Specifically, the clamping tool comprises a first clamping member 1 and a second clamping member 3, the CNC milling machine comprises a milling cutter and a multi-axis motion assembly, the milling cutter is connected to the multi-axis motion assembly, the milling cutter is used to process the weakly rigid workpiece, and the multi-axis motion assembly is used to drive the milling cutter to move along a preset trajectory.

[0051] In one embodiment, the CNC milling machine is a five-axis machine tool.

[0052] The following is a specific embodiment provided by the present invention:

[0053] like Figure 2 , Figure 3 and Figure 4 As shown in the figure, the symmetrical segmented alternating processing method for weak rigid workpieces mainly includes the following steps:

[0054] Step 1: Clamp both ends of a long weak-rigid workpiece 2 with a margin of 2 mm on the first clamp 1 and the second clamp 3 respectively, and then connect the first clamp 1 and the second clamp 3 to the A axes at the left and right ends of the AB structure five-axis machine tool respectively to complete the double-end clamping installation of the workpiece on the machine tool.

[0055] Step 2: Use milling to machine the groove C in three layers in the middle part of the weakly rigid workpiece 2 where the rigidity is weakest. When milling the groove C, machine 0.6 mm each time and leave a machining allowance of 0.2 mm in the end.

[0056] Step 3: According to the process experiment results, the weak rigid workpiece 2 is symmetrically divided into 8 sections, namely Figure 2 A1, A2, A3, A4 and B1, B2, B3, B4 shown in.

[0057] Step 4: Use left-right alternating processing, start processing from A1 area, and then alternate processing order is B1, A2, B2, A3, B3, A4, B4. For the left processing area A1, A2, A3, A4, spiral reverse milling is used, and the processing feed trajectory is as follows Figure 3 As shown by the arrow, the machining entry point for each area is the lower right corner of the area. Figure 3 As shown in the figure, for the right processing area B1, B2, B3, B4, spiral up-milling is also used, and the processing feed trajectory is as follows Figure 4 As shown by the arrow, the machining entry point for each area is the upper left corner of the area. Figure 4 PB points shown in .

[0058] Step 5: After the workpiece is processed, the first clamping member 1 and the second clamping member 3 are disassembled, and the weak rigidity workpiece 2 is taken out.

[0059] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for symmetrical segmented alternating machining of weak rigidity workpieces, characterized in that: The following steps are involved: Clamp and fix the two ends of the weak rigid workpiece along the length direction; The milling cutter is driven to machine a groove at a midline position in the length direction of the weak rigidity workpiece; Determine a critical symmetric segment size within which a weakly rigid workpiece can meet machining deformation requirements under a chatter-free cutting parameter condition; Dividing an area on one side of the groove into a plurality of first processing areas, and dividing an area on the other side of the groove into a plurality of second processing areas, wherein the width of each of the first processing area and the second processing area is not greater than the critical symmetric segment size; A plurality of the first processing areas and a plurality of the second processing areas are processed in sequence along the groove toward both ends of the weakly rigid workpiece, wherein the processing of the plurality of the first processing areas and the processing of the plurality of the second processing areas are performed alternately.

2. The method for symmetrically segmenting and alternatingly processing a weakly rigid workpiece according to claim 1, characterized in that: The weak rigidity workpiece has a first end and a second end along the width direction. In multiple first processing areas, the milling cutter feeds from the first end to the second end, and in multiple second processing areas, the milling cutter feeds from the second end to the first end.

3. The method for symmetrically segmenting and alternatingly processing a weakly rigid workpiece according to claim 1, characterized in that: The milling cutter rotates in a clockwise direction during the process of machining the first machining area and the second machining area.

4. The method for symmetrically segmenting and alternatingly processing a weakly rigid workpiece according to claim 1, characterized in that: The milling cutter rotates counterclockwise during the process of machining the first machining area and the second machining area.

5. The method for symmetrically segmenting and alternatingly processing a weakly rigid workpiece according to claim 1, characterized in that: The milling cutter is fed along a helical trajectory during the process of machining the first machining area and the second machining area.

6. The method for symmetrically segmented alternating machining of a weakly rigid workpiece according to claim 1, characterized in that: When processing the groove, the milling cutter processes in layers from top to bottom in sequence.

7. A processing device for implementing the symmetrical segmented alternating processing method of a weak rigidity workpiece as claimed in any one of claims 1 to 6, characterized in that: It includes a CNC milling machine and a clamping tool, wherein the clamping tool is used to clamp and fix the two ends of the weak rigidity workpiece along the length direction, the CNC milling machine includes a milling cutter and a multi-axis motion assembly, the milling cutter is connected to the multi-axis motion assembly, the milling cutter is used to process the weak rigidity workpiece, and the multi-axis motion assembly is used to drive the milling cutter to move along a preset trajectory.

8. The processing device according to claim 7, characterized in that: The CNC milling machine is a five-axis machine tool.

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