Five-axis automatic machining method for large marine fixed pitch propeller

Abstract

The invention relates to the technical field of ships, in particular to a five-axis automatic machining method for a fixed pitch propeller for a large ship. A machining model is established according to the propeller finished product data, and a machining area of the machining model is divided according to the propeller curvature; measuring the blank by using a three-dimensional scanner; optimizing machining parameters of the five-axis machine tool according to the measurement result of the blank; the five-axis machine tool machines a single blade of the propeller according to the divided machining areas; and after a single blade is machined, the next blade is skipped to be machined according to the blade angle. A five-axis machining program is adjusted according to the condition of a blank, the time consumed by trial cutting of the blank is saved, one blade of the propeller is machined firstly, after the current blade is machined, the next blade is skipped to be machined according to the angle of the blade till all the blades of the propeller are machined, and automatic machining of the large propeller is achieved. And the production efficiency is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of ships. Background Art

[0002] With the continuous progress of science and technology, ship design technology will also be improved and continuously improved and developed, which also puts higher requirements on the propellers used in supporting ships. Propeller products are gradually following the new design concept and development direction of "energy saving and green leadership", and are constantly optimized according to actual needs. The blanks of large-scale fixed-pitch propellers designed based on innovative concepts are large in size and have multiple curved surface combinations, but the modeling conditions cannot reach the state of precision casting, and the cutting surfaces such as multiple casting risers and sample blocks lead to uneven machining allowances of the blades; there are many blades, large pitch changes, small machining pitches, and many interference areas; the blanks are cast as a whole, and the machining allowances of each blade and semi-enclosed area vary greatly, which poses a great obstacle to mechanical processing. The above factors have brought huge challenges to the mechanical processing of large-scale fixed-pitch propellers for ships.

[0003] The common five-axis machine tool processing method usually cannot achieve efficient and high-quality processing due to the large difference between the program generated by the software and the actual blank working conditions, which limits the improvement of the economic benefits of the manufacturer. At the same time, it also has the following disadvantages:

[0004] (1) The post-processing program of the five-axis machine tool is generated based on the theoretical model and consists of several small processing areas. It is necessary to use a variety of tools with different specifications to generate the five-axis program. The blank working condition cannot be considered. In addition, due to the small processing area, it is necessary to use a variety of tools with different specifications to generate the five-axis program. As many as 40-50 processing programs need to be called in an interlaced manner according to the interference situation during mechanical processing. The processing risk and difficulty are very high, and quality problems are very likely to occur.

[0005] (2) When using program processing, since it is unknown whether the blank allowance is uniform, trial cutting can only be performed one by one by one in different areas and blades, and the operator needs to frequently use formulas to calculate the amount of cutting for each cut. If there are a large number of blades, the processing parameters need to be modified more than 200 times a day for 24-hour shift processing, which means that the parameters need to be changed approximately (200 times / day*30 working days / month*12 months) = 72,000 times per year. Each time the parameters are modified, the program must be reset and restarted, the processing process is not coherent, and the machine tool cannot be automated, which greatly reduces the effective processing time of the machine tool.

[0006] (3) The 24-hour uninterrupted operation of the machine has a high labor intensity. In addition, the operator is very likely to cause serious accidents such as overcutting of the workpiece, tool damage, and machine tool collision due to incorrect parameter input during the operation of the equipment, which is extremely dangerous. Summary of the invention

[0007] In order to solve the problems in the prior art that the blank condition is not considered during the processing of large-scale ship propellers and the degree of automation is low, the present invention provides a five-axis automated processing method for large-scale fixed-pitch ship propellers.

[0008] The technical solution adopted by the present invention to achieve the above-mentioned purpose is:

[0009] A five-axis automated processing method for a large-scale fixed-pitch propeller for a ship comprises the following steps:

[0010] S1. Use a three-dimensional scanner to measure the blank;

[0011] S2. Use NX software to establish a processing model based on the propeller finished product data, and divide the processing area of ​​the processing model according to the propeller curvature;

[0012] S3. Optimize the processing parameters of the five-axis machine tool according to the measurement results of the blank;

[0013] S4. The five-axis machine tool processes a single blade of the propeller according to the divided processing areas;

[0014] S5. After the five-axis machine tool completes processing of a single blade, it jumps to the next blade for processing according to the blade angle until all propeller blades are processed.

[0015] In step S1, the area where the propeller curvature deviation is less than 0.0015 is divided into a processing area.

[0016] The step S3 optimizes the program cutting speed according to the mutual interference between the blades: the tool speed is 800rpm-1500rpm, the cutting feed rate is 700mmpm-1500mmpm, the feed rate is 500mmpm-100mmpm, the retract rate is 600-1000mmpm, and the upper limit of the machine tool linkage speed is 25000mmpm-30000mmpm.

[0017] The calculation formula for optimizing the tool feed value in step S3 is as follows:

[0018] F2=(K1-K2)×F1

[0019] In the formula: F2 is the optimized feed value, K1 is the initial curvature, K2 is the optimized curvature, and F1 is the initial feed value.

[0020] In step S5, the center line of the R1 blade is used as the reference line, and R2 is the blade angle, and the calculation formula is as follows:

[0021]

[0022] R3=R3+(ap)

[0023] Where: ap is the cutting amount corresponding to different radius areas, and

[0024] When R3≤the finished blade angle, the processing of a single blade is finished, and then the next blade is processed according to formula R2.

[0025] The following steps are also included:

[0026] S6. According to steps S1-S5, propeller processing is simulated on a five-axis automated machine tool. If the five-axis machine tool prompts a processing error message, the tool speed, cutting feed rate, feed rate and retract rate of the five-axis machine tool are modified. If no processing error message is prompted, step S7 is executed;

[0027] S7. Use three-dimensional simulation software to simulate the tool path of the five-axis machine tool, and judge whether there is interference, overcutting, and collision between the spindle model of the simulated milling cutter model and the simulated blade model of the simulated machine tool spindle model during the machining swing according to the simulation results. If so, modify the machining parameters of the five-axis machine tool, if not, continue to execute step S8;

[0028] S8. According to the propeller diameter and hub height parameters, adjust the five-axis automated machine tool to a safe height, run the five-axis machine tool under no-load conditions, and observe whether the five-axis machine tool has a collision. If so, modify the tool speed, cutting feed rate, feed rate, and retract rate of the five-axis machine tool. If not, continue to step S9;

[0029] S9. Restart the five-axis automated machine tool and process the propeller.

[0030] The advantages of the present invention compared with the prior art are:

[0031] The five-axis machining program was adjusted according to the condition of the blank, saving the time consumed in trial cutting the blank. One blade of the propeller was machined first. After machining the current blade, the next blade was processed according to the blade angle until all the propeller blades were processed. This achieved automated machining of large propellers and improved production efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1The present invention is a flow chart of a five-axis automated processing method for a large-scale fixed-pitch propeller for a ship.

[0033] Figure 2 The present invention discloses a five-axis automated processing method for a large-scale fixed-pitch propeller for a ship, and a schematic diagram of repeated calling of a single path at the root R of a five-axis processing program.

[0034] Figure 3 The invention discloses a five-axis automated processing method and a five-axis automated processing route map at the root of a large-scale fixed-pitch propeller for a ship.

[0035] In the figure: 1. Feed direction; 2. Milling cutter disc; 3. Finished product contour; 4. Workpiece contour; 5. First tool path; 6. Second tool path; 7. Third tool path; 8. Fourth tool path; 9. Tool path; 10. Retract path; 11. Safe retract path; 12. Automatic blade change path. DETAILED DESCRIPTION

[0036] The present invention provides a five-axis automated processing method for a large-scale fixed-pitch propeller for a ship, such as Figure 1 As shown, the following steps are included:

[0037] S1. Use a method combining a 3D scanner and local trial cutting of the blade to measure the blank; 3D scanning cannot record the blank allowance of large castings in all directions, and must be combined with trial cutting of the protruding position, so as to accurately record the actual processing allowance of different areas of large marine fixed-pitch propeller blades.

[0038] S2. Use NX software to establish a processing model based on the finished propeller data, divide the processing area of ​​the processing model according to the propeller curvature, and edit the combination program; divide the area where the propeller curvature deviation is less than 0.0015 into one processing area. Since the curvature of different areas of the propeller is quite different, the blade surface is divided into different processing areas, and the areas with similar curvatures are divided into one processing area. Then, different attachment heads and tools are selected for processing according to the interference between the tool and the blade.

[0039] S3. Optimize the processing parameters of the five-axis machine tool according to the measurement results of the blank;

[0040] The optimization of five-axis machining parameters includes: taking the largest machining allowance of the blank as the starting point; reducing the tool feed speed as the propeller curvature increases according to the selected accessory head and tool cutting angle, appropriately reducing the feed speed at places with large curvature changes, and appropriately increasing the feed speed at places with small curvature changes to make the machining process smoother; and increasing the tool running speed in an absolutely safe position according to the interference between the propeller blades.

[0041] According to the mutual interference between the blades, the program cutting speed is optimized: the tool speed is 800rpm-1500rpm, the cutting feed rate is 700mmpm-1500mmpm, the feed rate is 500mmpm-100mmpm, the retract rate is 600-1000mmpm, and the upper limit of the machine tool linkage speed is 25000mmpm-30000mmpm.

[0042] The calculation formula for optimizing the tool feed value is as follows:

[0043] F2=(K1-K2)×F1

[0044] In the formula: F2 is the optimized feed value, K1 is the initial curvature, K2 is the optimized curvature, and F1 is the initial feed value. It changes automatically and the processing process is smoother.

[0045] The processing path of the blade is as follows Figure 2 shown.

[0046] S4. The five-axis machine tool processes a single blade of the propeller according to the structural characteristics of the blank and the divided processing area; the five-axis machining program produced by NX software is modified according to the structural characteristics of the blank and the selected accessory head and tool information; the modified five-axis machining program content includes the tool starting position, tool exit position and the safe height position for blade replacement processing, that is, the tool starting position is the position with the largest margin. After the five-axis machining program is modified, the five-axis program header and program tail produced by each NX software are deleted, and only the tool path part is intercepted, which is modified into SPF format and stored in the subroutine position of the five-axis automatic machine tool system.

[0047] S5. Edit the blank allowance, finished product position, feed rate per cut, number of blades, blade angle and cutter clearance of layered processing in the optimized five-axis machining program as variables, edit the macro program according to the correlation between the variables, and use the macro program to call the five-axis machining program of different machining areas to realize the automatic machining of the propeller. After the five-axis machine tool completes the machining of a single blade, it jumps to the next blade for machining according to the blade angle until all propeller blades are processed.

[0048] Edit the variable R1 as the blade number, R2 as the blade angle, R3 as the cutting amount for each processing, and R4 as the clearance distance for layered processing. Use the center line of the R1 blade as the reference line, and use R2 to represent the other blade positions. R2 is the blade angle. The calculation formula is:

[0049]

[0050] R3=R3+(ap)

[0051] Where: ap is the cutting amount corresponding to different radius areas, and

[0052] When R3≤the finished blade angle, the processing of a single blade is finished, and then the next blade is processed according to formula R2.

[0053] The macro program is used to frequently call five-axis programs in different areas, and combined with Siemens' TRANS, L9000, L9958 and other subroutines and editing codes, it performs conditional processing according to the calculation formula in the above macro program, thereby realizing the automation of large propeller processing, that is, automatic tool feeding and automatic blade changing.

[0054] Automated processing path such as Figure 3 As shown, the tool exits from the safe tool retraction path 11 along the tool path 9 through the tool retraction path 10. After completing the current blade, the tool moves to the next blade along the automatic leaf change path 12 according to the macro program to process the next blade.

[0055] S6. According to steps S1-S5, propeller processing is simulated on a five-axis automated machine tool. If the five-axis machine tool prompts a processing error message, the tool speed, cutting feed rate, feed rate and retract rate of the five-axis machine tool are modified. If no processing error message is prompted, step S7 is executed;

[0056] S7. Use three-dimensional simulation software to simulate the tool path of the five-axis machine tool, and judge whether there is interference, overcutting, and collision between the spindle model of the simulated milling cutter model and the simulated blade model of the simulated machine tool spindle model during the machining swing according to the simulation results. If so, modify the machining parameters of the five-axis machine tool, if not, continue to execute step S8;

[0057] S8. According to the propeller diameter and hub height parameters, adjust the five-axis machine tool to an absolutely safe position above the workpiece, operate the five-axis machine tool under no-load conditions, and observe whether the five-axis machine tool has a collision. If so, modify the processing parameters such as the tool speed, cutting feed rate, feed rate, and retract rate of the five-axis machine tool. If not, continue to execute step S9;

[0058] S9. Restart the five-axis automated machine tool and process the propeller.

[0059] The invention discloses a five-axis automated processing method for a large-scale fixed-pitch propeller for a ship, which can realize automated processing of cutting and blade replacement when processing a multi-blade propeller.

[0060] The invention discloses a five-axis automated processing method for a large-scale fixed-pitch propeller for a ship. Compared with five-axis processing generated by pure software, the method conforms to the actual blank working condition, reduces the scanning process, and is more flexible in operation and can be adjusted at any time.

[0061] The invention discloses a five-axis automated processing method for a large-scale fixed-pitch propeller for a ship. An operator only needs to observe the cutting state of a tool and does not need to adjust a processing ratio knob all the time, thereby reducing labor intensity.

[0062] The invention discloses a five-axis automated machining method for a large-scale fixed-pitch propeller for a ship. During the machining process, cutting parameters are reasonably set to reduce tool loss, increase effective machining time, reduce machining costs, and achieve cost reduction and efficiency improvement.

[0063] The invention discloses a five-axis automated processing method for a fixed-pitch propeller for a large ship. The method calculates that the parameters are changed 200 times less per day, and each time saves 1 minute. The effective processing time can be increased by (200 (minutes) / 60 (minutes / hour)=3.33 hours) per day, and the effective processing time can be increased by (12 (months / year)*25 (working days)*3.33 / (hour)) / 24 (hours / day)=37.5 days per year, thereby improving production efficiency.

[0064] The present invention discloses a five-axis automated machining method for a fixed-pitch propeller for a large ship. During the machining process, all variable parameters are calculated by a machine tool computer using formulas, thereby solving the problem of product quality caused by human operation errors, effectively controlling the machining risk of the product, ensuring the stability of product quality, and realizing the precision machining of fixed-pitch propellers for large ships.

[0065] The present invention is described by way of embodiments, and those skilled in the art will appreciate that various changes or equivalent substitutions may be made to these features and embodiments without departing from the spirit and scope of the present invention. In addition, under the teachings of the present invention, these features and embodiments may be modified to adapt to specific circumstances and materials without departing from the spirit and scope of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of this application belong to the protection scope of the present invention.

Claims

1. A five-axis automated processing method for a large-scale fixed-pitch propeller for a ship, characterized in that: The following steps are involved: S1. Use a three-dimensional scanner to measure the blank; S2. Use NX software to establish a processing model based on the propeller finished product data, and divide the processing area of ​​the processing model according to the propeller curvature; S3. Optimize the processing parameters of the five-axis machine tool according to the measurement results of the blank; S4. The five-axis machine tool processes a single blade of the propeller according to the divided processing areas; S5. After the five-axis machine tool completes processing of a single blade, it jumps to the next blade for processing according to the blade angle until all propeller blades are processed.

2. The five-axis automated processing method for a large fixed-pitch propeller for a ship according to claim 1 is characterized in that: In step S1, the area where the propeller curvature deviation is less than 0.0015 is divided into a processing area.

3. The five-axis automated processing method for a large fixed-pitch propeller for a ship according to claim 1 is characterized in that: The step S3 optimizes the cutting speed according to the mutual interference between the blades: the tool speed is 800rpm-1500rpm, the cutting feed rate is 700mmpm-1500mmpm, the feed rate is 500mmpm-100mmpm, the retract rate is 600-1000mmpm, and the upper limit of the machine tool linkage speed is 25000mmpm-30000mmpm.

4. The five-axis automated processing method for a large fixed-pitch propeller for a ship according to claim 1, characterized in that: The calculation formula for optimizing the tool feed value in step S3 is as follows: F2=(K1-K2)×F1 In the formula: F2 is the optimized feed value, K1 is the initial curvature, K2 is the optimized curvature, and F1 is the initial feed value.

5. The five-axis automated processing method for a large fixed-pitch propeller for a ship according to claim 1 is characterized in that: In step S5, the center line of the R1 blade is used as the reference line, and R2 is the blade angle, and the calculation formula is as follows: R3=R3+(ap) Where: ap is the cutting amount corresponding to different radius areas, and When R3≤the finished blade angle, the processing of a single blade is finished, and then the next blade is processed according to formula R2.

6. The five-axis automated processing method for a large fixed-pitch propeller for a ship according to claim 1, characterized in that: The following steps are also included: S6. According to steps S1-S5, propeller processing is simulated on a five-axis automated machine tool. If the five-axis machine tool prompts a processing error message, the tool speed, cutting feed rate, feed rate and retract rate of the five-axis machine tool are modified. If no processing error message is prompted, step S7 is executed; S7. Use three-dimensional simulation software to simulate the tool path of the five-axis machine tool, and judge whether there is interference, overcutting, and collision between the spindle model of the simulated milling cutter model and the simulated blade model of the simulated machine tool spindle model during the machining swing according to the simulation results. If so, modify the machining parameters of the five-axis machine tool, if not, continue to execute step S8; S8. According to the propeller diameter and hub height parameters, adjust the five-axis automated machine tool to a safe height, run the five-axis machine tool under no-load conditions, and observe whether the five-axis machine tool has a collision. If so, modify the tool speed, cutting feed rate, feed rate, and retract rate of the five-axis machine tool. If not, continue to step S9; S9. Restart the five-axis automated machine tool and process the propeller.

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