Gradient feeding turning method based on prolonging of service life of cutter

Abstract

The invention relates to a gradient feeding turning method based on prolonging of the service life of a tool, belongs to the technical field of machine tool cutting machining, solves the technical problem that the service life of the tool is short, and comprises the steps that according to machining requirements, a numerical control lathe turning tool is selected, and the turning tool is installed on a numerical control lathe; preparing a workpiece blank to be machined, and clamping the workpiece blank in a numerical control lathe fixture; measuring the cutter length of the turning cutter in the X direction and the Z direction, and inputting the cutter shape compensation value of the corresponding cutter number of the numerical control lathe; the programmed gradient feeding subprogram is input into the numerical control lathe, machining parameters are set, and the feeding speed calculated by the subprogram serves as the actual feeding speed; performing trial cutting processing on the workpiece according to a compiled program; measuring the structural size and the surface roughness of the machined workpiece blank, adjusting the gradient feeding subprogram, setting the feeding speed and the decreasing amount each time, and turning the workpiece according to the adjusted gradient feeding subprogram. The turning method is used for turning of a numerical control lathe.

Description

Technical Field

[0001] The invention belongs to the technical field of machine tool cutting and processing, and in particular relates to a progressive feed turning method based on extending the life of a tool. Background Art

[0002] With the development of machine tools and tool technology, hot turning technology is increasingly used in the processing of automotive transmission gear parts. Compared with traditional grinding technology, hot turning has the advantages of high processing efficiency, high flexibility, energy saving and environmental protection. As the final finishing process of the product, it requires a relatively small surface roughness value of the workpiece. In batch processing, the roughness often exceeds the tolerance due to the rapid wear of the blade, which poses a quality risk. At this time, the tool tip can only be replaced, which results in a low tool life and high processing cost.

[0003] Taking the gear of the intermediate shaft of the transmission as an example, the surface roughness of the inner hole after heat treatment is required to be below Ra0.8. Figure 1 As shown in the red area, when a fast-feed internal hole turning tool is used for boring on a CNC horizontal lathe, when the blade life reaches 400 pieces, the surface roughness value is close to the required upper limit. At this time, the tool tip needs to be replaced, and the cost of a single tool is 0.69 yuan.

[0004] The unit price of CBN blades used in hot turning is relatively expensive. In order to reduce the surface roughness of the workpiece, extend the life of the hot turning blades, and reduce processing costs, the method of reducing the cutting speed is usually adopted, but this will reduce processing efficiency and is not suitable for mass production; or the method of optimizing the blade material is adopted to improve the wear resistance of the tool, but it often has little effect. How to extend the life of the hot turning blades and maximize the value of the blades is still a technical problem that needs to be solved urgently. Summary of the invention

[0005] In order to overcome the shortcoming of low tool life of machine tools, the present invention proposes a progressive feed turning method based on extending tool life.

[0006] The technical solution adopted by the present invention to solve the technical problem is:

[0007] A variable feed turning method based on extending tool life comprises the following steps:

[0008] Step 1: Prepare the knife

[0009] According to the workpiece processing requirements, select the CNC lathe turning tool and install the turning tool on the CNC lathe.

[0010] Step 2: Prepare the workpiece blank

[0011] Prepare the workpiece blank for machining and clamp the workpiece blank in the CNC lathe fixture.

[0012] Step 3: Tool setting

[0013] Measure the tool length of the turning tool in the X and Z directions, and input the tool shape compensation value of the corresponding tool number of the CNC lathe.

[0014] Step 4: Programming

[0015] Prepare a progressive feed subroutine, input the prepared progressive feed subroutine into the CNC lathe, and set the processing parameters.

[0016] Add a subroutine call in the main program and use the feed rate calculated by the subroutine as the actual feed rate.

[0017] Step 5: Trial cutting

[0018] Start the CNC lathe processing program and perform trial cutting of the workpiece according to the programmed program.

[0019] Step 6: Workpiece precision measurement and processing

[0020] According to the design parameter accuracy requirements, measure the structural dimensions and surface roughness of the workpiece blank after processing.

[0021] According to the measurement results, adjust the incremental feed subroutine and set the feed speed and the amount of decrement each time.

[0022] Start the CNC lathe processing program and implement the workpiece turning process according to the adjusted incremental feed subroutine.

[0023] The above-mentioned progressive feed turning method, said step 1, further comprises:

[0024] Taking the boring of workpiece as the processing requirement, the fast feed boring tool bar is installed on the turret of the CNC lathe, and the fast feed blade is installed on the tool bar, and the blade pressure plate screw is locked.

[0025] The above-mentioned progressive feed turning method, step 2, further comprises:

[0026] The intermediate shaft gear is used as a workpiece blank and is clamped in a CNC lathe fixture.

[0027] In the above-mentioned progressive feed turning method, the step 4 further comprises:

[0028] Prepare user macro programs and set the initial feed speed, decrement value, and minimum feed speed in the incremental feed subroutine;

[0029] Increase the tool life count in the main program;

[0030] Then, in the subroutine, the feed speed after decreasing is calculated according to the current life and the set value, and the calculated feed speed is judged. If the calculated feed speed is greater than the minimum feed speed, the actual feed speed is the calculated feed speed, otherwise the actual feed speed is the minimum feed speed. The main program calls the actual feed speed at this time for processing.

[0031] The above-mentioned progressive feed turning method, step 5, further comprises:

[0032] Boring of intermediate shaft gears.

[0033] In the above-mentioned progressive feed turning method, the step 6 further comprises:

[0034] Measure the boring hole size and roughness value, adjust the progressive feed subroutine according to the precise measurement results, and set the feed speed parameters and the amount of decrement each time.

[0035] The above-mentioned progressive feed turning method further includes step 7, replacing the turning tool, and the specific process is as follows:

[0036] When the surface roughness of the workpiece blank after machining reaches the set value, the turning tool is replaced, the turning tool life is recorded, and the count in the CNC lathe is cleared.

[0037] The above-mentioned progressive feed turning method further includes step 8, batch processing, the specific process is as follows:

[0038] Follow step 6 to adjust the incremental feed subroutine and set the feed speed and the amount of decrement each time.

[0039] According to the turning tool life recorded in step 7, set the turning tool life in the main program.

[0040] Start the CNC lathe processing program and implement batch turning processing of workpieces.

[0041] The beneficial effects of the present invention are:

[0042] A variable feed turning method based on extending tool life is different from conventional turning, which uses a constant feed speed during the tool life cycle. Instead, it uses a turning method with a variable feed speed to automatically calculate the appropriate current feed speed based on the number of blades that have been processed, and delay blade wear and extend the blade life. This method is used to turn the inner hole of the intermediate shaft gear after heat treatment. The average cycle is the same as before, but the life of the same blade is extended from 400 pieces / blade to 600 pieces / blade, which is 50% longer, and the unit cost is reduced from 0.69 yuan to 0.46 yuan, which is 33.3% lower. This method has a significant effect of increasing life and reducing costs, and has good economic benefits.

[0043] A variable feed turning method based on extending tool life is suitable for scenarios where the blade fails prematurely due to excessive surface roughness in the field of post-heat turning. It has a wide range of applications and good versatility. This method is automatically completed through program functions without manual intervention, is easy to use, does not require changing the original tool model, and has zero cost for promotion and application. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 It is the intermediate shaft gear diagram;

[0045] Figure 2 is a flow chart of a progressive feed turning method according to an embodiment of the present invention;

[0046] Figure 3 This is a comparison chart of blade wear. The upper figure shows the blade for the constant feed turning method, and the lower figure shows the blade for the variable feed turning method. DETAILED DESCRIPTION

[0047] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0048] Embodiment 1

[0049] Taking the process of turning the inner hole of the intermediate shaft gear after heating as an example, the use process of this variable feed turning method is as follows:

[0050] 1) Prepare the tool; install the fast feed boring tool bar on the CNC lathe turret, install the fast feed blade on the tool bar, and lock the blade pressure plate screw.

[0051] 2) Prepare the workpiece; clamp the intermediate shaft gear blank in the machine tool fixture and clamp the workpiece.

[0052] 3) Tool setting: Measure the tool length in the X and Z directions in the machine tool, and modify the tool shape compensation value of the corresponding tool number.

[0053] 4) Programming: Input the variable feed subroutine into the machine tool and set appropriate parameters. Add the subroutine call to the main program and use the feed rate calculated by the subroutine as the actual feed rate.

[0054] 5) Trial cutting; start the program and complete the boring process.

[0055] 6) Precision measurement of workpieces; determine the boring hole size and roughness value, and adjust the subroutine to set the feed speed parameters and the amount of decrement each time according to the precision measurement results.

[0056] 7) Replace the blade: When the roughness approaches the upper limit, record the tool life at this time and reset the count (#701) to zero.

[0057] 8) Batch application: According to the parameters adjusted in step 6, the tool life is set according to the tool life recorded in step 7, and batch processing is performed automatically.

[0058] Embodiment 2

[0059] In order to extend the life of the hot turning blade, the present invention proposes a variable feed turning method. When the existing blade reaches the end of its life, the surface roughness increases, but the blade wear is still small at this time. According to the theoretical roughness calculation formula:

[0060]

[0061] Where, Rz = maximum profile height (μm), f = feed rate (r / min), r = tool tip radius (mm);

[0062] Reducing the feed rate f can reduce the surface roughness. Based on this principle, during the machining process, the feed rate f is gradually reduced as the tool has processed a certain amount of work, so as to delay the increase of roughness due to tool wear, increase the available cutting edge length of the blade, extend the tool life, maximize the value of the blade, and reduce machining costs.

[0063] The technical solution process of this method is as follows Figure 2 As shown, by compiling a user macro program, the initial feed speed, decrement value, and minimum feed speed are set in the subroutine; the tool life cumulative count is increased in the main program; and then the decremented feed speed is calculated in the subroutine according to the current life and the set value. If the calculated feed speed is greater than the minimum feed speed, the actual feed speed is the calculated feed speed, otherwise the actual feed speed is the minimum feed speed, and the main program calls the actual feed speed for processing.

[0064] According to the above solution flow, compile the machine tool subroutine. Taking the FANUC CNC system as an example, the program is as follows:

[0065] %

[0066] O4001;…………………………………………(subroutine name)

[0067] #1=0.45;…………………………………………(#1 indicates initial feed / mm / r)

[0068] #2=5; …………………………………………(#2 means the first 5 items remain unchanged, and the number decreases from the 6th item)

[0069] #3=2; ………………………………………………(#3 means decreasing by every 2 pieces)

[0070] #4=0.0008;……………………………………(#4 means decreasing by 0.0008 each time)

[0071] #5=0.3;……………………………………(#5 indicates minimum feed / mm / r)

[0072] #6=FIX[[#701-#2] / #3]; …………(#6 indicates the number of decrements)

[0073] IF[#701LE#2]THEN#1=#1;……………(first #2 pieces, feed speed remains unchanged)

[0074] IF[#701GT#2]THEN#1=#1-#6*#4;...(calculate the decreasing feed rate)

[0075] IF[#1LE#4]THEN#1=#4;………………(actual feed speed is the minimum feed speed)

[0076] M99;…………………………………………(Subroutine ends, return to main program)

[0077] %

[0078] In the above subroutine, #1 indicates the initial feed speed; #2 indicates that the feed speed of the first #2 pieces remains unchanged; #3 indicates that starting from the #2+1 piece, the feed speed decreases every #3 pieces; #4 indicates the amount of each decrease; #5 indicates the minimum feed speed; #6 indicates the number of decreases;

[0079] In the main program, it is necessary to call the subroutine and count the tool life. Taking the FANUC system as an example, the program is as follows:

[0080] %

[0081] O2001;…………………………………………(main program name)

[0082] …

[0083] T0101;…………………………………………(Call knife T1)

[0084] M98 P4001…………………………………………(Call feed speed calculation subroutine)

[0085] …

[0086] G01 Z-50.0F#1……………………………………(The speed calculated by the subroutine is used as the current feed speed)

[0087] #701=#701+1……………………………………(#701 indicates the number of processes completed by the current tool)

[0088] …

[0089] M30……………………………………………………(End of main program, return to the beginning)

[0090] %

[0091] In the above main program, #701 indicates counting the tool life, and #1 indicates the current feed speed.

[0092] The above sample program can be realized. The initial feed rate is 0.45mm / r. The feed rate of the first 5 pieces remains unchanged. Starting from the 6th piece, the feed rate is reduced by 0.0008 every two pieces, and it is reduced to the minimum of 0.3mm / r from the 382nd piece. After the 382nd piece, the minimum feed rate is used for processing. When the surface roughness approaches the upper limit, the tool needs to be changed, and the #701 count is cleared at the same time.

[0093] Through the application of the above example program, compared with the original constant feed speed of f = 0.35mm / r, the available cutting edge length of the fast feed turning tool is extended, such as Figure 3 As shown, the tool life is increased from 400 pieces / blade to 600 pieces / blade, which can ensure the surface roughness is below Ra0.8, and the tool life is increased by 50%; the unit cost is reduced from 0.69 yuan to 0.46 yuan, and the unit cost is reduced by 33.3%. This method is the same as the original speed, the beat is fast at first and then slow, and the average beat is basically the same as the original.

[0094] Embodiment 3

[0095] A variable feed turning method based on extending tool life, taking the boring of intermediate shaft gears by a CNC lathe as an example, comprises the following steps:

[0096] Step 1: Prepare the knife

[0097] According to the requirements of the workpiece to be processed, select the CNC lathe turning tool and install the turning tool on the CNC lathe.

[0098] Specifically, a fast-feed boring tool bar is installed on a turret of a CNC lathe, and a fast-feed blade is installed on the tool bar, and a blade pressure plate screw is locked.

[0099] Step 2: Prepare the workpiece blank

[0100] Prepare the workpiece blank for machining and clamp the workpiece blank in the CNC lathe fixture.

[0101] Specifically, the intermediate shaft gear is clamped in a fixture of a CNC lathe.

[0102] Step 3: Tool setting

[0103] Measure the tool length of the turning tool in the X and Z directions, and input the tool shape compensation value of the corresponding tool number of the CNC lathe.

[0104] Step 4: Programming

[0105] Prepare a progressive feed subroutine, input the prepared progressive feed subroutine into the CNC lathe, and set the processing parameters.

[0106] Add a subroutine call in the main program and use the feed rate calculated by the subroutine as the actual feed rate.

[0107] Step 5: Trial cutting

[0108] Start the CNC lathe processing program and perform trial cutting of the workpiece according to the programmed program.

[0109] Specifically, boring processing is performed on the intermediate shaft gear blank.

[0110] Step 6: Workpiece precision measurement and processing

[0111] According to the design parameter accuracy requirements, measure the structural dimensions and surface roughness of the workpiece blank after processing.

[0112] According to the measurement results, adjust the incremental feed subroutine and set the feed speed and the amount of decrement each time.

[0113] Start the CNC lathe processing program and implement the workpiece turning process according to the adjusted incremental feed subroutine.

[0114] Specifically, the boring hole size and roughness value are measured, and according to the precise measurement results, the progressive feed subroutine is adjusted to set the feed speed parameters and the amount of each decrement.

[0115] Step 7: Replace the turning tool

[0116] When the surface roughness of the workpiece blank after machining reaches the set value, the turning tool is replaced, the turning tool life is recorded, and the count in the CNC lathe is cleared.

[0117] Step 8: Batch processing

[0118] Follow step 6 to adjust the incremental feed subroutine and set the feed speed and the amount of decrement each time.

[0119] According to the turning tool life recorded in step 7, set the turning tool life in the main program.

[0120] Start the CNC lathe processing program and implement batch turning processing of workpieces.

Claims

1. A progressive feed turning method based on extending tool life, characterized in that: The following steps are involved: Step 1, prepare the knife: According to the workpiece processing requirements, select CNC lathe turning tools and install the turning tools on the CNC lathe; Step 2: Prepare the workpiece blank: Prepare the workpiece blank for machining and clamp the workpiece blank in the fixture of the CNC lathe; Step 3, tool setting: Measure the tool length of the turning tool in the X and Z directions, and input the tool shape compensation value of the corresponding tool number of the CNC lathe; Step 4, program: Prepare a progressive feed subroutine, input the prepared progressive feed subroutine into the CNC lathe, and set the processing parameters; Add a subroutine call in the main program and use the feed rate calculated by the subroutine as the actual feed rate; Step 5, trial cutting: Start the CNC lathe processing program and perform trial cutting of workpieces according to the programmed program; Step 6: Workpiece precision measurement and processing: According to the design parameter accuracy requirements, measure the structural dimensions and surface roughness of the workpiece blank after processing; According to the measurement results, adjust the progressive feed subroutine and set the feed speed and the amount of each decrement; Start the CNC lathe processing program and implement the workpiece turning process according to the adjusted incremental feed subroutine.

2. The variable feed turning method according to claim 1, characterized in that: The step 1 further includes: taking the boring of the workpiece as the processing requirement, installing the fast feed boring tool bar on the turret of the CNC lathe, installing the fast feed blade on the tool bar, and locking the blade pressure plate screw.

3. The progressive feed turning method according to claim 2, characterized in that: The step 2 further comprises: using the intermediate shaft gear as a workpiece blank, and clamping the intermediate shaft gear in a fixture of a CNC lathe.

4. The progressive feed turning method according to claim 1, characterized in that: The step 4 further comprises: Prepare user macro programs and set the initial feed speed, decrement value, and minimum feed speed in the incremental feed subroutine; Increase the tool life count in the main program; Then, in the subroutine, the reduced feed speed is calculated according to the current life and the set value, and the calculated feed speed is judged; if the calculated feed speed is greater than the minimum feed speed, the actual feed speed is the calculated feed speed, otherwise the actual feed speed is the minimum feed speed; the main program calls the actual feed speed at this time for processing.

5. The progressive feed turning method according to claim 3, characterized in that: The step 5 further includes: performing boring processing on the intermediate shaft gear.

6. The progressive feed turning method according to claim 5, characterized in that: The step 6 further includes: measuring the boring hole size and roughness value, adjusting the progressive feed subroutine according to the precise measurement results, and setting the feed speed parameters and the amount of each decrement.

7. The progressive feed turning method according to claim 1, characterized in that: The step 7 is also included, which is to replace the turning tool. The specific process is as follows: When the surface roughness of the workpiece blank after machining reaches the set value, the turning tool is replaced, the turning tool life is recorded, and the count in the CNC lathe is cleared.

8. The progressive feed turning method according to claim 7, characterized in that: It also includes step 8, batch processing, the specific process is: Follow step 6 to adjust the incremental feed subroutine and set the feed speed and the amount of decrement each time; According to the turning tool life recorded in step 7, set the turning tool life in the main program; Start the CNC lathe processing program and implement batch turning processing of workpieces.

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