Method for layering of a sawtooth thread

Abstract

The application discloses a layered processing method of sawtooth thread, comprising the following steps: processing preparation: selecting an appropriate profile groove cutter; clamping and fixing a workpiece to be processed; rough layered cutting: taking the cutting edge of the profile groove cutter as a processing reference, adopting a layered cutting mode with multiple infeeds along the radial direction of the thread, the single radial cutting depth being 0.2mm-0.3mm, and gradually cutting to a preset position close to the thread bottom; layered fitting processing is performed according to the tooth profile contour of the sawtooth thread, and a finishing allowance of 0.1mm-0.2mm is reserved after rough processing; the thread tooth angle and the thread pitch are corrected to eliminate the form and position errors caused by rough processing, so that the tooth profile contour meets the design requirements of the drawing; the transition arc of the thread bottom is pre-finished to ensure smooth transition of the arc; and the single radial cutting depth is controlled within the range of 0.1mm-0.2mm in finishing, and the sawtooth thread is processed to the design size of the thread bottom. The application has the advantages of high processing stability, high automation degree and high processing efficiency.

Description

Technical Field

[0001] This application relates to the field of thread processing technology, and in particular to a layered processing method for sawtooth threads. Background Technology

[0002] YS type asymmetric sawtooth internal thread, especially large-specification heavy-duty sawtooth internal thread with nominal diameter of 300mm-1000mm and pitch of 20mm-36mm, is a core component of heavy-duty transmission systems in mining machinery, metallurgical equipment, heavy presses, etc. Typical application is split transmission nuts. This type of thread has extremely high requirements for tooth profile accuracy, tooth pitch consistency, tooth root arc transition quality, and tooth surface roughness, which directly determines the transmission stability and component service life under heavy load conditions.

[0003] Currently, the industry-standard machining method for this type of large-specification sawtooth internal thread is a one-time cutting process using integral forming tools. However, this process has insurmountable industry pain points when machining the aforementioned specific dimensions:

[0004] (1) The cutting resistance is too high and the machining stability is extremely poor. The thread tooth depth is large and the total cutting allowance is large in this size range. The integral forming tool needs to contact the entire thread tooth profile for cutting, and the cutting resistance is extremely high. Especially for large diameter, semi-circular split non-circular workpieces with a diameter of more than 500mm, the clamping rigidity is much lower than that of the whole circular workpiece, which can easily cause the tool to vibrate and deflect, resulting in tooth profile angle deviation and tooth pitch error exceeding the tolerance, and the finished product qualification rate is extremely low.

[0005] (2) The degree of automation is low and the processing efficiency is low. The workpieces in this size range have large processing allowances and poor rigidity. Traditional processing methods cannot achieve continuous and stable cutting. Frequent machine stops are required to check and correct the tools and processing parameters. There is a lot of manual intervention, high labor intensity, and extremely low production efficiency. Summary of the Invention

[0006] This application aims to at least partially solve one of the technical problems in the aforementioned technologies.

[0007] To achieve the above objectives, the first aspect of this application proposes a layered machining method for sawtooth threads, comprising: S100, pre-machining preparation: S101, selecting a forming grooving cutter with a cutting edge width one-third to one-half of the tooth pitch of the sawtooth thread to be machined; S102, using a CNC lathe as the machining equipment, clamping and fixing the workpiece to be machined, and setting the spindle speed; S200, rough machining layered cutting: S201, using the cutting edge of the forming grooving cutter as the machining reference, employing a layered cutting method with multiple feeds along the thread radial direction, with a single radial cutting depth of 0.2mm-0.3mm. S202. Gradually cut to a preset position close to the bottom of the thread tooth; S203. Perform layered fitting machining according to the tooth profile of the sawtooth thread, and leave a finishing allowance of 0.1mm-0.2mm after rough machining; S204. Correct the tooth profile angle and tooth pitch of the thread to eliminate the form and position errors remaining from rough machining, so that the tooth profile meets the design requirements of the drawing; S205. Perform pre-finishing of the transition arc of the thread tooth bottom to ensure a smooth transition of the arc; S306. Finish machining: control the radial cutting depth in a single operation within the range of 0.1mm~0.2mm, and machine to the design dimension of the sawtooth thread tooth bottom.

[0008] In addition, the layered machining method for sawtooth threads proposed in this application may also have the following additional technical features:

[0009] As a further description of the above technical solution: the radius of the tip arc of the forming groove cutter is consistent with the radius of the transition arc of the tooth root of the thread to be processed, and matches the tooth profile angle of the thread to be processed.

[0010] As a further description of the above technical solution: In step S200, rough machining layer cutting, the cutting speed is 45m / min-55m / min, and the feed per revolution is equal to the pitch value of the sawtooth thread to be machined.

[0011] As a further description of the above technical solution: In step S300, during finishing, the cutting speed is 50m / min-60m / min, and the feed per revolution is equal to the pitch value of the sawtooth thread to be machined.

[0012] As a further description of the above technical solution: the preset position is the radial position corresponding to the design dimension of the tooth root of the sawtooth thread to be processed plus the finishing allowance.

[0013] As a further description of the above technical solution: In step S202, the layered fitting process according to the tooth profile of the sawtooth thread can be achieved in any of the following ways: Method 1: Build a centralized parameter input interface to realize the one-time input of processing parameters, and automatically calculate the built-in R parameter. After starting, the automated processing does not require manual intervention; Method 2: Use CNC programming software to set the layered data according to the design requirements of the drawing, and automatically generate the processing program for processing.

[0014] As a further description of the above technical solution: the method of correcting the thread profile angle and pitch in step S203 is as follows: the tool path is compensated and adjusted according to the design dimensions of the drawing by CNC automatic programming or numerical control macro programming.

[0015] As a further description of the above technical solution: the workpiece to be processed with sawtooth threads is a forged steel part, which has undergone normalizing or quenching and tempering heat treatment before clamping.

[0016] As a further description of the above technical solution: In step S200, roughing layer cutting, and step S300, finishing, cutting oil is continuously sprayed to cool and lubricate the cutting area, simultaneously completing the cooling and chip removal of the cutting area.

[0017] According to the layered machining method for sawtooth threads in this application, a forming groove cutter with a cutting edge width of 3mm is used, which greatly reduces the cutting contact area between the tool and the workpiece, reduces radial cutting resistance, solves the inherent defects of traditional processes such as high cutting resistance, easy tool vibration, and tool breakage, and significantly enhances the stability of the machining process.

[0018] The quantitative parameters of 0.2mm-0.3mm radial cutting depth in roughing, 0.1mm-0.2mm radial cutting depth in finishing, and 0.1mm-0.2mm finishing allowance in roughing form a standardized layered cutting control. This avoids tool breakage and ensures machining stability. Combined with CNC programming, the machining process is highly automated. Layered machining of thread tooth height allows for continuous machining without stopping the machine for inspection, resulting in higher machining efficiency.

[0019] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0020] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the following description of the embodiments taken in conjunction with the accompanying drawings, wherein:

[0021] Figure 1 This is a schematic flowchart of a layered machining method for sawtooth threads according to an embodiment of this application;

[0022] Figure 2 This is a schematic diagram of a sawtooth thread according to an embodiment of this application;

[0023] Figure 3 This is a BB enlarged cross-sectional view of a sawtooth thread according to an embodiment of this application; Detailed Implementation

[0024] The embodiments of this application are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this application, and should not be construed as limiting this application.

[0025] The layered processing method for sawtooth threads according to embodiments of this application will now be described with reference to the accompanying drawings.

[0026] like Figure 1 As shown, the layered machining method for sawtooth threads according to an embodiment of this application includes the following steps:

[0027] S100, Preparation before processing.

[0028] Specifically, the steps include step S101, selecting a forming grooving cutter with a cutting edge width that is one-third to one-half of the tooth pitch of the sawtooth thread to be processed. The radius of the cutting tip arc of the forming grooving cutter is consistent with the radius of the tooth root transition arc of the thread to be processed, and matches the tooth profile angle of the thread to be processed.

[0029] It should be noted that the sawtooth thread targeted in this application is a YS-type asymmetric sawtooth internal thread, especially large-specification heavy-duty sawtooth internal threads with nominal diameters of 300mm-1000mm and pitches of 20mm-36mm. Based on the characteristic of the target specification thread pitch width of 6mm-9mm, for example, by selecting a forming grooving cutter with a cutting width of 3mm, the cutting width is exactly in the optimal range of 1 / 3-1 / 2 of the pitch width. Compared with traditional full-width forming cutters, the cutting contact area between the tool and the workpiece can be greatly reduced, thereby reducing radial cutting resistance from the root and solving the core defects of traditional processes such as high cutting resistance and easy tool vibration and breakage.

[0030] Meanwhile, the radius of the tool tip arc is consistent with the radius of the transition arc of the thread root, which can ensure that the final machined tooth root arc completely conforms to the drawing requirements and avoids stress concentration at sharp corners and steps; the tool tooth profile angle matches the tooth profile angle of the thread to be machined, which can ensure the accuracy of the tooth profile angle after cutting and avoid tooth profile deviation.

[0031] Step S102: Use a CNC lathe as the processing equipment, clamp and fix the workpiece to be processed with sawtooth threads, and set the spindle speed.

[0032] It should be noted that, given the poor clamping rigidity of large-diameter, split, non-circular workpieces, a CNC lathe is used to ensure the feed accuracy and spindle stability during machining. Secure clamping ensures the coaxiality of the workpiece during machining, preventing vibration and dimensional errors caused by loose clamping. Simultaneously, the spindle speed is matched to the workpiece material, laying the foundation for matching cutting parameters in subsequent roughing and finishing processes, thus ensuring the stability of the cutting process and tool life.

[0033] Step S200: Rough machining with layered cutting, wherein the cutting speed is 45m / min-55m / min, and the feed per revolution is equal to the pitch value of the sawtooth thread to be machined.

[0034] It should be noted that the cutting speed of 45m / min-55m / min is the optimal cutting range for carbon steel and alloy structural steel forgings commonly used for the target specification threads. This range balances cutting efficiency and tool wear rate, avoiding tool breakage due to excessive cutting speed and low machining efficiency due to excessive cutting speed. The feed per revolution is equal to the pitch value, ensuring that the tool accurately feeds one pitch distance axially for every one revolution of the spindle. This prevents thread breakage at the source, ensures consistent tooth pitch, and is fully compatible with the machining requirements of large pitch threads of 20mm-36mm.

[0035] Specifically, the process includes step S201, using the cutting edge of the forming groove cutter as the machining reference, employing a multi-step layered cutting method along the radial direction of the thread, with a single radial cutting depth of 0.2mm-0.3mm, gradually cutting to a preset position close to the bottom of the thread tooth.

[0036] Understandably, given the characteristics of large thread depth and large total cutting allowance of the target specification thread, layered machining with a single radial cutting depth of 0.2mm-0.3mm is adopted. This avoids the problems of increased cutting resistance, tool vibration, and tool breakage caused by excessive single cutting depth, while also avoiding the low machining efficiency caused by excessively small cutting depth without quantitative standards, thus achieving a balance between machining stability and efficiency.

[0037] By repeatedly advancing the tool in layers, most of the cutting allowance is gradually removed, and the tool is finally cut to a preset position close to the tooth root, leaving a controllable machining space for subsequent finishing.

[0038] Step S202: Perform layered fitting machining according to the sawtooth thread tooth profile. After rough machining, leave a finishing allowance of 0.1mm-0.2mm. It should be noted that by performing layered fitting machining, it is ensured that the trajectory of each layer of cutting is consistent with the final thread tooth profile, so that the tooth profile after rough machining gradually conforms to the design requirements of the drawing, avoiding large deviations in the rough machining tooth profile; at the same time, leaving a finishing allowance of 0.1mm-0.2mm provides sufficient space for dimensional correction and surface finishing in the finishing stage, avoiding the form and position errors of rough machining from directly affecting the accuracy of the final product, and ensuring that the dimensions and surface roughness requirements of the drawing are fully met after finishing.

[0039] The preset position is the radial position corresponding to the design dimension of the tooth root of the sawtooth thread to be processed plus the finishing allowance.

[0040] Step S203: Correct the thread profile angle and pitch to eliminate residual form and position errors from rough machining, so that the tooth profile conforms to the design requirements of the drawing.

[0041] It should be noted that, in the roughing layer cutting process, the tooth profile angle deviation and tooth pitch error caused by cutting force and tool deflection are specifically corrected in the roughing stage. This eliminates the residual form and position errors in the roughing process in advance, so that the tooth profile after roughing is close to the design requirements of the drawing. This greatly reduces the correction pressure in finishing, avoids the finished product from exceeding the tolerance due to excessive roughing error, and ensures the consistency of the tooth profile accuracy and tooth pitch of the final thread.

[0042] Step S204: Perform pre-finishing on the transition arc of the thread root to ensure a smooth transition of the arc.

[0043] It should be noted that pre-finishing the transition arc at the tooth root during the roughing stage ensures a smooth arc without steps or sharp corners. This eliminates deviations in the arc profile caused by roughing, preventing insufficient finishing allowance from correcting arc defects. Furthermore, it eliminates stress concentration points at the tooth root, ensuring the structural strength and service life of the final product under heavy loads, thus addressing the difficulty in controlling the quality of the tooth root arc in traditional processes. Step S300: Finishing, where the cutting speed is 50m / min-60m / min, and the feed per revolution is equal to the pitch of the sawtooth thread to be machined. The single radial cutting depth is controlled within the range of 0.1mm-0.2mm, machining to the designed dimension of the sawtooth thread tooth root.

[0044] It should be noted that a cutting speed of 50m / min-60m / min is slightly higher than that of roughing. Combined with a small single radial cutting depth of 0.1mm~0.2mm, the cutting force can be effectively reduced, ensuring the smoothness of the tooth surface and consistently achieving the surface roughness required by the drawing. The feed per revolution is equal to the pitch value, which ensures that the tooth profile trajectory of finishing is completely aligned with that of roughing, avoiding tooth misalignment. Finally, the thread is machined to the design size of the thread root, completing the entire sawtooth thread machining process.

[0045] Specifically, to clearly illustrate the embodiments of this application, the specific processing procedure is described in detail using the YS650×24H9 type asymmetric sawtooth internal thread as an example:

[0046] like Figure 2 and Figure 3 As shown in the drawing, the YS type asymmetric sawtooth internal thread has a nominal diameter of 650mm, a pitch of 24mm, a working face tooth angle of 45°, a tooth root design dimension of 626mm, a tooth root transition arc radius of R1.2, a tooth pitch width of 6.64mm, and a tooth surface roughness requirement of Ra3.2. The workpiece is a forging and has undergone normalizing heat treatment.

[0047] Based on the above parameters, a carbide forming grooving cutter with a cutting edge width of 3mm is selected, with a tip radius of R1.2 (consistent with the tooth root transition radius in the drawing), and a tool tooth angle of 45° (matching the tooth angle of the thread to be machined). The single radial cutting depth is selected as 0.25mm (within the range of 0.2mm-0.3mm), the cutting speed is selected as 50m / min (within the range of 45m / min-55m / min), the feed per revolution is 24mm (equal to the pitch value), and a finishing allowance of 0.15mm is reserved (within the range of 0.1mm-0.2mm). The calculated preset position close to the tooth root is 626mm + 0.15mm = 626.15mm.

[0048] The single radial cutting depth is selected as 0.15mm (within the range of 0.1mm-0.2mm), the cutting speed is selected as 55m / min (within the range of 50m / min-60m / min), the feed per revolution is 24mm (equal to the pitch value), and the final machining target is a tooth root design size of 626mm.

[0049] Based on the nominal diameter, tooth root design dimension, single radial cutting depth, and reserved finishing allowance, calculate the number of layered cutting operations. That is, with a nominal diameter of 650mm, a tooth root design dimension of 626mm, a single radial cutting depth in roughing of 0.25mm, and a reserved finishing allowance of 0.15mm, the total tooth depth on one side (total radial cutting allowance) = (nominal diameter - tooth root design dimension) ÷ 2 = (650 - 626) ÷ 2 = 12mm; the allowance to be removed on one side during roughing = total... Single-sided tooth depth - single-sided finishing allowance = 12mm - 0.15mm = 11.85mm; Theoretical number of cuts = single-sided allowance to be removed during roughing ÷ single radial cutting depth = 11.85mm ÷ 0.25mm / cut = 47.4 cuts. The number of cuts must be a positive integer and there must be no overcutting that damages the workpiece. Therefore, it is rounded up to 48 cuts. The single cutting depth of the last cut can be finely adjusted to 0.1mm to ensure that the final cut is accurately cut to the preset position of 626.15mm.

[0050] It should be noted that if the single radial cutting depth in roughing is taken as the upper limit of 0.3mm, the total number of roughing operations is about 40; if the lower limit of 0.2mm is taken, the total number of operations is about 60.

[0051] As per design requirements, a carbide forming grooving cutter with a cutting edge width of 3mm was selected. The tip radius was confirmed to be R1.2, consistent with the tooth root transition radius on the drawing. The tool tooth angle was 45°, matching the tooth angle of the thread to be machined. A CNC lathe was used as the machining equipment. The 650mm diameter sawtooth thread forged steel workpiece was securely clamped and fixed. Based on the 42CrMo alloy steel material and cutting parameters, the roughing spindle speed was set.

[0052] The cutting speed during the roughing stage is controlled at 50 m / min, and the feed per revolution is 24 mm, which is equal to the pitch value of the thread to be machined. The cutting edge of the 3 mm forming groove cutter is used as the machining reference. The layered cutting method with multiple feeds is adopted along the radial direction of the thread. The single radial cutting depth is 0.25 mm, and the total number of layered cuttings is 48, gradually cutting to the preset position close to the bottom of the thread tooth.

[0053] The sawtooth thread profile is fitted and processed in layers. After rough machining, a finishing allowance of 0.15mm is reserved. The 45° tooth profile angle and 6.64mm tooth pitch of the thread are corrected to eliminate the form and position errors remaining from rough machining, so that the tooth profile meets the design requirements of the drawing. The R1.2 transition arc at the bottom of the thread tooth is pre-finished to ensure a smooth transition of the arc without steps or sharp corners.

[0054] During the finishing stage, the cutting speed is controlled at 55 m / min, the feed per revolution is 24 mm, which is equal to the pitch value of the thread to be machined, and the single radial cutting depth is controlled at 0.15 mm. Finally, the design dimension of 626 mm for the root of the sawtooth thread is reached, thus completing the entire thread machining process.

[0055] In one embodiment of this application, step S202 involves layered fitting processing based on the sawtooth thread profile, which can be achieved using any of the following methods:

[0056] Method 1: Build a centralized parameter input interface to achieve one-time input of processing parameters. The built-in R parameter is automatically calculated, and automated processing is required after startup without manual intervention.

[0057] It should be noted that this method is applicable to mainstream CNC systems such as Siemens 840D / 828D. By building a visual centralized parameter input window on the CNC system HMI (Human-Machine Interface), all core machining parameters can be entered at once. The built-in R parameter (a common variable parameter in Siemens CNC systems) automatically completes the calculation of the number of layers, the radial infeed position of each cut, and the tooth profile trajectory. After the program is started, the system automatically calls the calculation results to perform layered fitting machining, without the need for manual intervention throughout the process.

[0058] The core advantage lies in the fact that operators do not need to have complex macro programming skills. They only need to enter basic parameters according to the drawings, which greatly reduces the reliance on the operator's experience and perfectly adapts to the production characteristics of multiple varieties and small batches of target specifications.

[0059] Method 2: Use CNC programming software to set layered data according to the design requirements of the drawings, and automatically generate the machining program for processing.

[0060] It should be noted that this method is applicable to industry-standard CNC programming software such as UGNX, Mastercam, and SolidCAM. Through the software's "Thread Layer Milling / Turning" module, core parameters such as thread specifications and layer data are set at once according to the drawing design requirements. The software automatically calculates the radial infeed position for each cut, plans the tool path consistent with the final tooth profile, and automatically generates a G-code machining program that conforms to the corresponding CNC system format. After importing the generated program into the CNC lathe, the layer fitting machining can be started.

[0061] Its core advantage lies in its high accuracy and strong compatibility in toolpath planning. It can be adapted to CNC lathes of different brands and models without the need to write macro programs for specific systems, making it more versatile.

[0062] Specifically, to clearly illustrate the embodiments of this application, the specific processing procedure is described in detail using the YS650×24H9 type sawtooth internal thread as an example:

[0063] like Figure 2 and Figure 3 As shown in the drawing, the YS type asymmetric sawtooth internal thread has a nominal diameter of 650mm, a pitch of 24mm, a working face tooth angle of 45°, a tooth root design dimension of 626mm, a tooth root transition arc radius of R1.2, a single tooth pitch axial width of 6.64mm, and a tooth surface roughness requirement of Ra3.2. The workpiece is a forging and has undergone normalizing heat treatment.

[0064] In Method 1, the operator sets up a visualization window on the CNC system and sets the following parameter input boxes: nominal diameter (R1), tooth root design dimension (R2), pitch (R3), working face tooth profile angle (R4), tooth root transition arc radius (R5), single radial cutting depth in roughing (R6), and reserved finishing allowance (R7).

[0065] Then, the operator enters the following values ​​in the corresponding input boxes according to the drawing requirements: R1=650, R2=626, R3=24, R4=45, R5=1.2, R6=0.25, R7=0.15.

[0066] The system's built-in R parameters automatically perform the following core operations:

[0067] Total tooth depth on one side: R8=(R1-R2) / 2=(650-626) / 2=12;

[0068] The allowance to be removed on one side during rough machining: R9 = R8 - R7 = 12 - 0.15 = 11.85;

[0069] Rough machining is divided into layers: R10 = INT(R9 / R6) + 1 = INT(11.85 / 0.25) + 1 = 47 + 1 = 48;

[0070] The system automatically generates 48 variables from R11 to R58, which correspond to the radial feed positions from the 1st to the 48th cut. Based on R3, R4, and R5, the system automatically generates an axial feed path that is completely consistent with the final thread profile.

[0071] After the parameters are entered, click the "Start Machining" button. The system will automatically call the calculation results to perform layered fitting machining. From the first cut to the 48th cut, the tool path of each cut is completely consistent with the final thread profile. No manual intervention is required throughout the process.

[0072] In Method 2, open the UGNX CNC programming software, import the 3D model or 2D tooth profile of the handover drawing, enter the "Turning" module, select the "Thread Layer Turning" sub-module, and in the "Thread Parameter Settings" interface of the software, enter the following values ​​as required by the handover drawing: Thread type: YS type asymmetric sawtooth internal thread; Major diameter (nominal diameter): 650mm; Minor diameter (tooth root design size): 626mm; Pitch: 24mm; Working face tooth profile angle: 45°; Tooth root transition arc radius: 1.2mm.

[0073] In the software's "Layered Cutting Settings" interface, enter the following values ​​according to the previous parameter design: single radial cutting depth in roughing is 0.25mm; allowance for finishing is 0.15mm; number of roughing layers is 48.

[0074] After setting the parameters, click the "Generate Toolpath" button. The software will automatically calculate the radial infeed position for each cut, plan the toolpath that is consistent with the final tooth profile, and display the toolpath visually on the interface. After confirming that the toolpath is correct, click the "Post-processing" button, select the post-processing file for the corresponding CNC lathe, and automatically generate a G-code machining program that meets the format requirements.

[0075] The generated G-code program is imported into the CNC lathe via USB flash drive or network transfer. After confirming that the program is correct, the layered fitting machining is started. From the first cut to the 48th cut, the tool path of each cut is completely consistent with the final thread profile, and no manual intervention is required throughout the process.

[0076] In one embodiment of this application, step S203, correcting the thread profile angle and pitch, is performed by compensating and adjusting the tool path according to the design dimensions in the drawing through CNC automatic programming or numerical control macro programming.

[0077] It should be noted that this step is the core precision control step in the roughing stage. Its core function is to specifically eliminate problems such as tooth profile angle deviation and tooth pitch deviation caused by cutting force deflection, tool wear, machine tool spindle-feed synchronization error, and insufficient workpiece clamping rigidity during the roughing layered cutting process. It calibrates the tooth profile after roughing to the design requirements in advance, avoiding residual form and position errors from roughing that exceed the correction range of the finishing allowance. The correction in this step is based on the tooth profile angle and tooth pitch design values ​​marked on the drawing. Through two standardized paths, CNC automatic programming or CNC macro programming, the trajectory of the last tool pass in roughing is precisely compensated and adjusted in reverse to offset the measured form and position deviations, ultimately ensuring that the tooth profile after roughing perfectly matches the design requirements of the drawing.

[0078] Understandably, CNC automatic programming is used to achieve tool path compensation and adjustment. Relying on the thread profile compensation and pitch error compensation functions built into the CNC programming software, the measured tooth angle and pitch deviation values ​​after rough machining are entered into the software. The software uses the design dimensions in the drawing as a reference and automatically performs reverse compensation calculation on the original layered fitting tool path to generate a machining program with correction parameters. The compensation is performed in the last pass of rough machining to offset the measured deviation and make the final tooth profile conform to the drawing requirements.

[0079] By writing CNC macro programs to achieve tool path compensation and adjustment, it is compatible with mainstream CNC systems such as FANUC and Siemens. It is fully compatible with the automatic calculation method of R parameters in the layered fitting machining in step S202. There is no need to repeatedly import and export machining programs. Deviation correction can be completed quickly on site. It is highly flexible and suitable for single-piece production scenarios with multiple varieties and small batches.

[0080] In one embodiment of this application, during step S200 (roughing layer cutting) and step S300 (finishing), cutting oil is continuously sprayed to cool and lubricate the cutting area, simultaneously cooling and removing chips from the cutting area.

[0081] It should be noted that the continuous spray cooling and lubrication, which starts and stops simultaneously with the cutting action and is executed without interruption throughout the entire process, is a key supporting measure for this solution to address industry pain points such as easy wear and chipping of traditional cutting tools, easy scratching of tooth surfaces by chips, and poor machining stability. This further amplifies the advantages of this solution in terms of machining stability, accuracy, and efficiency.

[0082] In summary, the layered machining method for sawtooth threads according to the embodiments of this application uses a forming grooving cutter with a cutting edge width of 3mm, which significantly reduces the cutting contact area between the tool and the workpiece, reduces radial cutting resistance, and solves the inherent defects of traditional processes such as high cutting resistance, easy tool vibration, and tool breakage. The stability of the machining process is significantly enhanced. The quantitative parameters of 0.2mm-0.3mm single radial cutting depth in roughing, 0.1mm-0.2mm single radial cutting depth in finishing, and 0.1mm-0.2mm finishing allowance reserved in roughing form a standardized layered cutting control, which avoids tool breakage and ensures machining stability. Combined with CNC programming, the machining has a high degree of automation. Layered machining of thread tooth height can be carried out continuously without stopping the machine for inspection, resulting in higher machining efficiency.

[0083] In the description of this specification, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0084] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0085] Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of this application.

Claims

1. A method for layered machining of sawtooth threads, characterized in that, include: S100, Preparation before processing: S101. Select a forming groove cutter with a cutting edge width that is one-third to one-half of the pitch of the sawtooth thread to be processed. S102. A CNC lathe is used as the processing equipment. The workpiece to be processed with sawtooth threads is clamped and fixed, and the spindle speed is set. S200, roughing layered cutting: S201. Using the cutting edge of the forming groove cutter as the machining reference, a multi-step layered cutting method is adopted along the radial direction of the thread, with a single radial cutting depth of 0.2mm-0.3mm, gradually cutting to a preset position close to the bottom of the thread tooth. S202. Perform layered fitting machining according to the tooth profile of the sawtooth thread, and leave a finishing allowance of 0.1mm-0.2mm after rough machining; S203. Correct the tooth profile angle and tooth pitch of the thread to eliminate the form and position errors remaining from rough machining, so that the tooth profile conforms to the design requirements of the drawing. S204. Pre-finish the transition arc at the bottom of the thread to ensure a smooth transition. S300, finishing: the single radial cutting depth is controlled within the range of 0.1mm-0.2mm, and the cutting is carried out to the design dimension of the sawtooth thread root.

2. The sawtooth thread layering processing method according to claim 1, characterized in that, The radius of the tip arc of the forming groove cutter is consistent with the radius of the transition arc of the tooth root of the thread to be processed, and matches the tooth profile angle of the thread to be processed.

3. The sawtooth thread layering processing method according to claim 1, characterized in that, In step S200, during rough machining and layered cutting, the cutting speed is 45m / min-55m / min, and the feed per revolution is equal to the pitch of the sawtooth thread to be machined.

4. The sawtooth thread layering processing method according to claim 1, characterized in that, In step S300, during finishing, the cutting speed is 50m / min-60m / min, and the feed per revolution is equal to the pitch of the sawtooth thread to be machined.

5. The sawtooth thread layering processing method according to claim 1, characterized in that, The preset position is the radial position corresponding to the design dimension of the tooth root of the sawtooth thread to be processed plus the finishing allowance.

6. The sawtooth thread layering processing method according to claim 1, characterized in that, In step S202, the layered fitting process based on the sawtooth thread profile can be achieved using any of the following methods: Method 1: Build a centralized parameter input interface to achieve one-time input of processing parameters. The built-in R parameter is automatically calculated, and automated processing is required after startup without manual intervention. Method 2: Use CNC programming software to set layered data according to the design requirements of the drawings, and automatically generate the machining program for processing.

7. The sawtooth thread layering processing method according to claim 1, characterized in that, The method for correcting the thread profile angle and pitch in step S203 is as follows: by using CNC automatic programming or CNC macro programming, the tool path is compensated and adjusted according to the design dimensions in the drawing.

8. The sawtooth thread layering processing method according to claim 1, characterized in that, The workpiece to be processed with sawtooth threads is a forged steel part, which has undergone normalizing or quenching and tempering heat treatment before clamping.

9. The sawtooth thread layering processing method according to claim 1, characterized in that, In step S200, roughing and layered cutting, and in step S300, finishing, cutting oil is continuously sprayed to cool and lubricate the cutting area, simultaneously cooling and removing chips from the cutting area.

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