TW201513955A - Numerical control system and method for accelerating screw thread-cutting and improving cutting accuracy - Google Patents

Abstract

A numerical control system for accelerating screw thread-cutting and improving cutting accuracy includes a processing machine and a numerical control device, and the numerical control device provides users to key-in specific screw thread type for calculating the retraction time of a cutter of the processing machine, so the motion plan of the x-axis and z-axis of the cutter can be achieved by numerical control device, therefore, it can get the purpose of improving production efficiency, decreasing cost, and simplifying production process.

Description

Numerical control system and method for improving thread turning speed and machining accuracy

The invention relates to a numerical control system and a method thereof, in particular to a numerical control system for improving the thread turning speed and machining precision and a numerical control method thereof.

The main applications of lathe machining are mainly thread turning. However, the problems faced by thread turning machining at present are to improve the machining accuracy of the thread and the quality of the tool retracting when threading, in other words, to reduce the thread and the tooth. Complete tooth generation, wherein the invalid tooth refers to the thread pitch produced by the thread turning is less than the set thread pitch, and the incomplete tooth means that the tool is not urgent when the thread turning is finished. When the knife is pulled, the incomplete thread with the thread deeper than the thread is left; otherwise, if the thread pitch and the thread depth are the correct thread, it is called the effective tooth.

In the general lathe numerical control system, the lathe G code can be divided into three systems: A, B and C. The following are the G code of the lathe of the A system.

There are two kinds of machining commands for the numerical control system of thread turning cycle machining, namely G92 straight turning and G76 oblique turning, G92 straight turning machining instructions (eg G92 X(U)_ Z(W)_ R_ H_ ( F_ or E_); where X and Z are the absolute values of the turning end coordinates; U and W are the incremental values of the turning end coordinates; R is the taper difference; F is the lead of the metric thread (unit: mm/tooth); Leading for inch thread (unit: tooth/mm); H is the number of multi-nozzles; F is the pitch of the adjacent thread)) Straight-in feed, but turning the workpiece at the same time on both sides of the tool, turning force Although it is large, it is not easy to remove chips, so it is easy to cause tool grinding. Loss, which leads to errors in thread making, but its thread turning accuracy is high, so it is often used for thread turning with small thread pitch and high thread precision. The disadvantage of the G92 straight turning instruction is the movement and turning of the tool. All need to be edited by machining instructions. Therefore, if the G92 straight-turn turning command is used for thread turning cycle processing, it is necessary to use a multi-row G92 straight-turn turning command to complete the thread turning cycle.

G76 oblique feed turning instruction (eg: G76 P mra Q Δdmin R d ; G76 X(U)_ Z(W)_ R Δi P Δk Q Δd H_ (F_ or E_); where m is the number of finishing vehicles ( 1~99);r is the retracting length. When the pitch is expressed by L, the set value can be from 0.0L to 9.9L, the unit is 0.1L; a is the tool nose angle; Δdmin is the minimum cutting depth; R d is the finishing car Reserved amount; X(U) is the X-axis coordinate of the turning end; Z(W) is the Z-axis coordinate of the turning end; Δi is the thread radius difference; Δk is the thread height; Δd is the first cutting depth; F is the metric Thread lead (unit: mm/tooth); E is the lead of the inch thread (unit: teeth/inch); H is the number of multiple threads. The workpiece is machined by one-sided cutting, so that the thread surface of the workpiece is not Straight, and the tool tip is easy to wear, resulting in poor thread precision, but its advantage is that the chip removal is easy, and its turning depth is decreasing, so it is suitable for thread turning with large pitch pitch and low thread precision.

However, whether using the G76 oblique turning machining command or the G92 straight turning machining command, the thread turning cycle machining path is the same. The schematic diagram of the one thread turning cycle machining path is shown in Fig. 1, where a tool 11 Positioned at a starting point 1A, the tool 11 is then positioned along the physical axis of motion X to a designated turning depth point 1B so that the tool 11 can contact a machined workpiece 12 for thread turning.

When the tool 11 reaches the specified turning depth point 1B, the machining rotation axis (not shown in FIG. 1) of the workpiece 12 is started to rotate, and the tool 11 starts turning by the specified turning depth point 1B along a solid motion axis Z direction. To the retraction starting point 1C, the tool 11 is pulled away from the surface of the workpiece 12 according to the retraction distance and the retracting angle set by the user, and passes through a retracting end point 1D to the turning end point 1E, and returns again. Starting point 1A, complete a thread turning cycle.

Please refer to Fig. 2, which is a schematic diagram showing the axial speed versus time of the oblique retraction of the thread turning process of the prior art.

As shown in Fig. 2, when the tool 11 is from the retraction starting point 1C to the retracting end point 1D, the movement of the tool 11 along the solid motion axis X and the solid motion axis Z must be in the same dynamic relationship, and therefore, in the solid motion The speed planning of the axis X and the solid motion axis Z needs to meet the combined direction speed. However, the speed Vx of the tool 11 in the direction of the solid motion axis X is accelerated from the stationary state, and during the initial acceleration period, the target speed cannot be reached instantaneously. The speed Vz of the tool 11 in the direction of the solid motion axis Z is lowered, resulting in an increase in the overall machining time and also in the wrong thread pitch.

Next, please refer to FIG. 3, which is a flow chart of the thread turning cycle processing of the prior art.

First, as shown in step 201, a thread turning cycle machining instruction is input first, and then step 202 is performed. After inputting a thread lead angle and a thread lead angle according to the final thread specification, step 203 is performed, that is, step 203 is performed. According to the thread turning cycle machining instruction, the thread lead angle and the thread lead angle input in steps 201 and 202, a thread turning cycle is started. After the thread turning cycle is finished, step 204 is performed to view the thread. Whether the result of the turning cycle processing conforms to the specification. If the specification is not met, step 205 is performed, that is, the thread lead angle and the thread lead angle value are re-adjusted again, and the process returns to step 202 to input the thread lead angle and the thread lead value again. Steps 203 and 204 are performed in sequence, and steps 202 to 205 are repeatedly executed until the thread turning cycle processing result meets the specifications, then step 206 can be performed, that is, a large number of batches are started according to the correct thread lead angle and the thread lead angle value. Threaded workpiece production, in order to achieve product specifications during this thread turning cycle processing must depend on the use Practical experience, but according to the user's practical experience, it is easy to cause processing error. In addition, repeating the correction of the thread lead angle and the thread lead value and then checking the thread processing result will increase the overall processing time, which does not meet the numerical control. The essence of automation.

According to the above, in the conventional thread turning cycle processing, repeatedly adjusting the thread lead angle value and the thread lead angle angle not only the material loss of the workpiece but also increases the production cost, and because the processing process also needs to be dependent on the user. real Experience, if you need to produce different specifications of the thread, you must also re-set the thread lead angle and thread lead angle and re-examine the machining results; in addition, the retracting path of the thread turning cycle machining path must reduce the tool along the solid axis of motion The Z direction also leads to an increase in overall processing time. In the long run, it not only increases production costs, but also reduces production efficiency.

In order to solve the problems described in the prior art, the main object of the present invention is to improve the numerical control method of the thread turning speed and the machining precision, comprising the steps of: inputting a thread processing program to a numerical control device, comprising a quick positioning movement program and A thread turning program, a numerical control device for controlling the operation of a tool of a processing machine; a thread type for a numerical control device comprising a metric thread and an inch thread; and a physical movement axis of the tool according to the thread type X and one of the physical motion axes Z retracting time; according to the retracting time, one of the physical motion axis X and the solid motion axis Z is axially motion-planned, and an interpolation operation is performed to generate an X-axis interpolation command and a Z-axis interpolation command; integrated X-axis interpolation command and Z-axis interpolation command is a retracting program; and the retracting and threading program is a final machining program.

The numerical control method for improving the thread turning speed and the machining precision, wherein the processing machine is a horizontal processing machine.

Still another main object of the present invention is to provide a numerical control system for improving the speed and machining accuracy of a thread, comprising a machining machine having a tool and a machining rotary shaft, wherein the machining rotary shaft is used for clamping a machining workpiece, the machining system Located above the machined workpiece, it moves along a solid motion axis X, a solid motion axis Y or a solid motion axis Z, and performs a thread turning process on the machined workpiece, a solid motion axis X, a solid motion axis Y, and a solid motion axis Z. The two are perpendicular to each other, and a numerical control device is electrically connected to the processing machine for loading and executing a threading program, and controlling the tool along the solid motion axis X, the physical motion axis Y, and the solid motion according to the thread processing program. The movement of the axis Z, wherein the numerical control system for improving the thread turning speed and the machining accuracy is characterized in that the numerical control device can provide a user input Thread type to machining program, the thread type includes one metric thread and one inch thread, so that the numerical control device calculates the tool retracting time from the bottom of the workpiece to the workpiece according to the thread type, and the solid motion axis according to the retracting time. After X and Z perform an axial motion planning, an interpolation operation is performed to generate an X-axis interpolation command and a Z-axis interpolation command, which are further integrated into a retracting program, and the X-axis interpolation command needs to be advanced in advance. Sending and controlling the motion axis X motion of the entity, and then sending a Z-axis interpolation command to control the movement of the solid motion axis Z, after which the numerical control device integrates the retracting program and the threading program into a final machining program.

The numerical control system for improving the thread turning speed and the machining precision, wherein the processing machine is a horizontal processing machine.

According to the above, the numerical control system for improving the thread turning speed and the machining precision of the present invention can provide the user input thread type without repeatedly setting the thread lead angle and the thread lead angle value, and can calculate the exact according to the thread type. The retraction time can be achieved without increasing the speed of the physical movement axis Z when the tool is retracted, thereby improving machining efficiency, reducing development costs, and simplifying the production process.

11, 311‧‧‧Tools

12, 313‧‧‧ machining workpiece

1A, 3A‧‧‧ starting point

1B, 3B‧‧‧ turning depth point

1C, 3C‧‧‧Retraction starting point

1D, 3D‧‧‧ retraction end

1E, 3E‧‧‧ Turning cycle end point

X, Y, Z‧‧‧ physical movement axes

201~206, 401~407‧‧‧ steps

300‧‧‧Numerical control system for increasing the speed and machining accuracy of thread turning

31‧‧‧Processing machine

312‧‧‧Processing rotary axis

32‧‧‧Numerical control device

Vx‧‧‧ physical movement axis speed in the X direction

Speed of the Vz‧‧‧ physical motion axis in the Z direction

Figure 1 is a schematic view of a thread turning cycle machining path of the prior art.

Fig. 2 is a schematic view showing the relationship between the axial speed and the time of the oblique retracting of the thread turning process of the prior art.

Figure 3 is a flow chart of a conventional thread turning cycle machining process.

Figure 4 is a schematic diagram of the numerical control system for improving the thread turning speed and machining accuracy of the present invention.

Figure 5 is a schematic view of the machining path of a thread turning cycle of the present invention.

Figure 6 is a flow chart of the thread turning cycle processing of the present invention.

The invention discloses a lifting thread turning speed and machining precision The Numerical Control (NC) system, in which the basic thread turning cycle machining instruction is utilized, is well known to those skilled in the relevant art, and therefore will not be fully described in the following description. At the same time, the drawings in the following texts express the structure and function of the features of the present invention, and do not need to be completely drawn according to the actual size, which will be described first.

The invention relates to a numerical control system for improving the thread turning speed and machining precision, in particular to a numerical control system for improving the thread turning speed and machining precision including a processing machine and a numerical control device.

First, please refer to Fig. 4, which is a schematic diagram of the numerical control system for improving the turning speed and machining accuracy of the thread of the present invention.

As shown in FIG. 4, the numerical control system 300 for improving the thread turning speed and machining accuracy of the present invention comprises a processing machine 31, which may be a horizontal processing machine having a cutter 311 and a machining rotary shaft 312. a solid motion axis X, a solid motion axis Y, and a solid motion axis Z, and the physical motion axis X, the physical motion axis Y, and the solid motion axis Z are perpendicular to each other, wherein the machining rotation axis 312 is used to clamp one The workpiece 313 is processed, and the cutter 311 is located above the machining workpiece 313. When the thread turning cycle machining is performed, the cutter 311 is moved along the solid motion axis X, the solid motion axis Y and the solid motion axis Z direction, and the lifting thread of the present invention. The numerical control system for turning speed and machining accuracy further includes a numerical control device 32 electrically coupled to the processing machine 31 for loading and executing a threading program and controlling the operation of the tool 311, and providing user input. The type of thread, the thread type includes one metric thread and one inch thread, and the numerical control device 32 calculates the tool 311 completely off the bottom of the workpiece 313 according to the thread type. After the retracting time of the workpiece 313 is processed, and the physical motion axes X and Z are subjected to an axial motion planning according to the retracting time, an interpolation operation is performed to generate an X-axis interpolation command and a Z-axis interpolation command, which are further integrated into one. Retracting the program, and determining that the X-axis interpolation command needs to be sent in advance of the retracting time to control the movement of the solid motion axis X, and then send the Z-axis interpolation command to control the movement of the solid motion axis Z, after which the numerical control device 32 will retract the program. The threading program is a final machining program that simplifies the thread turning cycle and is subsequently mass produced in the final machining program.

Next, please refer to FIG. 5, which is a schematic diagram of a machining path of a thread turning cycle according to the present invention.

As shown in Fig. 5, the cutter 311 is first positioned at a starting point 3A, and then the cutter 311 is lowered along the solid motion axis X direction to a turning depth point 3B so that the cutter 311 can contact the machined workpiece 313 for thread turning.

When the cutter 311 is in contact with the machining workpiece 313, the machining rotary shaft 312 of the workpiece machining workpiece 313 is rotated, and the cutter 311 is moved from the turning depth point 3B along the solid motion axis Z direction, and the workpiece 313 is turned to a retracting start. At point 3C, at this time, the numerical controller 32 calculates a retracting time of the tool 311 from the bottom of the workpiece 313 to completely away from the machining workpiece 313 based on the type of thread input by the user, and the numerical control device 32 further performs the retracting time according to the retracting time. The axial motion planning of the solid motion axis X and the solid motion axis Z, and then the numerical control device 32 performs an interpolation operation on the axial motion planning result to generate an X-axis interpolation command and a Z-axis interpolation command respectively, and the numerical control device 32 further integrates the X-axis interpolation command and a Z-axis interpolation command into a retracting program, and the retracting program determines that the X-axis interpolation command needs to be sent in advance of the retracting time to control the movement of the solid motion axis X, and then sends the Z-axis. The interpolation command controls the movement of the solid motion axis Z, after which the numerical control device 32 integrates the retracting program and the threading program into a final machining program, wherein the tool 311 moves to the retracting end point 3C at the retracting starting point 3C. The retracting action is completed according to the retracting program. Then, the tool 311 moves from the retracting end point 3D along the solid moving axis X direction to the end point of a turning cycle 3E, and finally Then, the cutter 311 moves from the turning end point 3E along the solid motion axis Z direction to the starting point 3A to complete the path of the thread turning cycle processing.

Next, please refer to FIG. 6 , which is a flow chart of the thread turning cycle processing of the present invention.

First, as shown in step 401, a threading program is first input to the numerical control device 32. The threading program mainly includes a rapid positioning movement program and a thread turning machining program, and the numerical control device 32 is used to control the cutter 311 of the processing machine 31. Operation, that is, the numerical control device 32 controls the tool 311 from the starting point 3A along the thread according to the rapid positioning movement program of the threading program and the thread turning program. The movement axis X direction moves to the turning depth point 3B, the tool 311 is turned from the turning depth point 3B in the solid motion axis Z direction to the retracting starting point 3C, and the tool 311 moves from the retracting end point 3D in the solid motion axis X direction to the turning cycle. The end point 3E and the tool 311 are moved from the turning cycle end point 3E in the solid motion axis Z direction to the starting point 3A, and then step 402 is performed, and a thread type is input to the numerical control device 32. The thread type includes a metric thread and an inch thread. Then, in step 403, the numerical control device 32 can obtain the relationship between the thread pitch and the thread depth according to the type of the thread, and can further calculate the physical motion axis X of the tool 311 and the solid motion axis Z from the bottom of the workpiece 313 to completely leave the machining. The retracting time of the workpiece 313 is then proceeded to step 404, and the numerical control device 32 performs the axial motion planning of the X-axis and the Z-axis of the tool 311 along the physical motion axis according to the retracting time obtained in step 403, and performs an interpolation operation. An X-axis interpolation command and a Z-axis interpolation command are respectively generated, and then step 405 is performed, and the numerical control device 32 performs the X-axis interpolation command completed in step 404 with the Z-axis. The interpolation command is integrated into a retracting program, and it is determined that the X-axis interpolation command needs to be sent in advance of the retracting time to control the movement of the solid motion axis X, and then the Z-axis interpolation command is sent to control the movement of the solid motion axis Z, so that the numerical control device 32 controls The tool 311 moves from the retraction starting point 3C to the retracting end point 3D according to the retracting program, and in step 406, the retracting program obtained in step 405 and the threading processing program input in step 401 are integrated into a final machining program. Finally, step 407 is a mass production of the thread turning cycle processing according to the final machining program, without repeatedly setting the thread lead angle and the thread lead angle value, and calculating the exact retracting time according to the thread type without lowering The speed at which the tool moves the shaft Z at the time of retracting can achieve the purpose of improving machining efficiency, reducing development costs, and simplifying the production process.

The above description is only the preferred embodiment of the present invention, and is not intended to limit the scope of the present invention. The above description should be understood and implemented by those skilled in the relevant art, so that the other embodiments are not disclosed. Equivalent changes or modifications made under the spirit shall be included in the scope of the patent application.

401~407‧‧‧Steps

Claims (4)

A numerical control method for improving the speed and machining accuracy of a thread, comprising the steps of: inputting a threading program to a numerical control device, comprising inputting a rapid positioning movement program and a thread turning machining program, wherein the numerical control device is used for controlling An operation of a tool of a processing machine; inputting a thread type to the numerical control device, comprising inputting a metric thread and an inch thread; calculating a physical movement axis X of the tool and a physical movement axis Z according to the thread type a retracting time; performing an axial motion planning of the physical motion axis X and the solid motion axis Z according to the retracting time, and performing an interpolation operation to generate an X-axis interpolation command and a Z-axis interpolation command respectively; Integrating the X-axis interpolation command and the Z-axis interpolation command into a retracting program; and integrating the retracting program and the threading program into a final machining program. The numerical control method for improving the thread turning speed and the machining precision according to the second application of the patent application scope, wherein the processing machine is a horizontal processing machine. A numerical control system for improving the thread turning speed and machining accuracy, comprising a processing machine having a cutter and a machining rotary shaft, wherein the machining rotary shaft is used for clamping a machining workpiece, the cutter is located above the machining workpiece Moving along a solid motion axis X, a solid motion axis Y or a solid motion axis Z, and performing a thread turning process on the machined workpiece, the solid motion axis X, the solid motion axis Y, and the solid motion axis Z system Two perpendicular to each other, and a numerical control device electrically connected to the processing machine for loading and executing a threading program, and controlling the movement axis of the tool along the solid axis X according to the thread machining program Y and the physical movement The movement of the shaft Z, wherein the numerical control system for the speed and the machining accuracy of the lifting thread is characterized in that the numerical control device provides a user input of a thread type comprising a metric thread and an inch thread, such that the value The control device calculates, according to the thread type, a retraction time of the tool completely from the bottom of the workpiece, and performs an axial motion planning of the solid motion axes X and Z according to the retracting time. An interpolation operation respectively generates an X-axis interpolation command and a Z-axis interpolation command, further integrated into a retraction program, and determines that the X-axis interpolation command needs to be sent in advance of the retracting time to control the movement axis X movement of the entity, and then The Z-axis interpolation command is further sent to control the movement of the physical motion axis Z, and then the numerical control device integrates the retraction program with the thread machining program into a final machining program. A numerical control system for improving the thread turning speed and machining accuracy according to item 3 of the patent application scope, wherein the processing machine is a horizontal processing machine.