JP2006000995A - Thread cutting apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thread cutting apparatus which shortens the length of an incomplete thread portion, and also shortens the total machining time for thread cutting by increasing the rotational speed of a main spindle. <P>SOLUTION: A numerically controlled (NC) lathe 10 comprises a main spindle 20, a main spindle motor 230, a tool rest 340 movable relative to the main spindle 20, a Z-axis feed motor 320 for driving the tool rest 340 in the axial direction in parallel with the main spindle 20, and an X-axis feed motor 350 for driving the tool rest 340 in the direction perpendicular to the main spindle 20. The NC lathe 10 forms a screw having a complete thread portion and an incomplete thread portion on a workpiece W by means of a cutting tool 400 by moving the tool rest 340 relative to the workpiece W held by the main spindle 20. An NC unit 100 controls the Z-axis feed motor 320 and the main motor 230 by the synchronous interpolation by controlling the main spindle motor 230 such that the rotational speed of the main spindle in cutting the incomplete thread portion is lower than that of the main spindle in cutting the complete thread portion. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a thread cutting apparatus.

A conventional threading process in a numerically controlled machine tool such as an NC lathe will be described with reference to FIGS.
As shown in FIGS. 14A and 14B, when threading a workpiece 500, the workpiece 500 is rotated about a main shaft (not shown) as a rotation center, and from the approach portion to the peripheral portion of the workpiece 500. On the other hand, the working tool 510 is moved in the Z-axis direction parallel to the axis O of the main spindle in synchronization with the rotation of the workpiece 500 while the machining tool 510 is brought into contact with each other, thereby forming an effective screw portion. FIG. 14B is a side view as viewed from the end on the effective screw portion side, and the arrow indicates the rotation direction of the workpiece 500. Then, in the vicinity of the end point of the machining cycle of the effective thread portion, in order to pull out the machining tool 510 from the thread groove, a rounding up operation in the X-axis direction orthogonal to the Z-axis direction is performed (FIGS. 15A to 15 ( c)).

  Therefore, this portion becomes an incomplete screw portion having a shallow screw groove (see FIG. 14A). Since the incomplete thread portion becomes longer as the main shaft rotational speed becomes faster, it is necessary to lower the main shaft rotational speed from an appropriate value for cutting when the incomplete thread portion becomes longer than in the design drawing instruction. Conventionally, as shown in FIGS. 15 (a) to 15 (c), in the effective screw portion and the incomplete screw portion, the spindle rotation speed is kept constant, and threading is performed by biaxial interpolation of the Z axis and the X axis. Like to do.

Patent Document 1 discloses the synchronous control between the machining tool and the spindle in thread cutting and screw hole machining.
JP-A-11-245118

  However, conventionally, as described above, the spindle speed is kept constant even in the area where the effective thread part and the incomplete thread part are machined. When it becomes longer, the spindle rotation speed is lowered from an appropriate value for cutting so that the incomplete thread portion does not become longer. However, when the spindle rotational speed is lowered, there is a problem that the machining time including the effective screw portion and the incomplete screw portion becomes long.

  In addition, in patent document 1, although threading can be performed in a short time by synchronous control of a processing tool and a spindle, technical matters on how to perform an incomplete thread portion are disclosed. Absent.

  An object of the present invention is to provide a threading device that can shorten the length of an incomplete thread portion and increase the rotational speed of the main shaft to shorten the total processing time of threading.

In order to solve the above-mentioned problem, the invention according to claim 1 includes a spindle for holding a workpiece,
A spindle driving means for rotationally driving the spindle, a tool rest provided with a processing tool, and driving at least one of the spindle and the tool rest to move in a first axial direction parallel to the axis of the spindle. A first driving means; a second driving means for driving at least one of the spindle and the tool post in a second axis direction orthogonal to the first axis direction; the spindle driving means; the first driving means; Control means for controlling and driving each of the second driving means, and by moving the main spindle and the tool rest relative to each other, an effective thread portion on the work held on the main spindle by a processing tool of the tool rest, In the threading device capable of forming a screw having an incomplete thread portion, the control means is configured such that the spindle rotational speed when machining the incomplete thread portion is greater than the spindle rotational speed when machining the effective thread portion. small Thread cutting, characterized in that the spindle driving means is controlled so that at least one of the first driving means and the second driving means is controlled by synchronous interpolation together with the spindle driving means. The gist of the processing apparatus.

  According to a second aspect of the present invention, in the first aspect, the control means rotates the spindle in at least an incomplete screw portion region of an effective screw portion region and an incomplete screw portion region where the workpiece is processed by the processing tool. The number is changed so as to be gradually reduced.

  According to a third aspect of the present invention, in the first or second aspect of the present invention, the control unit is configured to perform the first driving so that the pitch of the screw in the effective screw region and the pitch of the screw in the incomplete screw region are the same. Of the means and the second driving means, at least the first driving means and the spindle driving means are controlled by synchronous interpolation.

  According to a fourth aspect of the present invention, in the first aspect, the control means is configured to maintain a constant spindle rotational speed in the effective screw portion region of the effective screw portion region and the incomplete screw portion region where the workpiece is processed by the processing tool. In the incomplete thread portion region, the spindle rotational speed is changed so as to gradually decrease.

  According to a fifth aspect of the present invention, in the first aspect, the control unit is configured to control the spindle rotational speed in the effective screw portion region of the effective screw portion region and the incomplete screw portion region where the workpiece is processed by the processing tool. After the control is made constant, the spindle speed is controlled to gradually decrease, and in the incomplete thread area, the spindle speed is continuously changed from the effective thread area to be gradually decreased. It is characterized by.

  A sixth aspect of the present invention is the first aspect of the present invention, wherein the control means has a constant spindle rotational speed in the effective screw portion region of the effective screw portion region and the incomplete screw portion region where the workpiece is processed by the processing tool. After that, the spindle rotational speed is controlled so as to gradually decrease, and in the incomplete thread portion area, the spindle rotational speed that is less than the constant spindle rotational speed made constant in the effective thread portion area is made constant. It is characterized by controlling.

  The invention according to claim 7 includes processing length calculation means for calculating a processing length of the incomplete thread portion based on a processing length related parameter, the processing length and the incomplete thread portion included in the processing length related parameter. According to the magnitude relation of the upper limit value of the machining length, the control means controls the spindle rotational speed to be constant in the effective screw portion region and the incomplete screw portion region, or any one of claims 4 to 6. The control described in item 1 is performed.

  The invention of claim 8 provides the machining length-related parameter according to claim 7, wherein the machining length-related parameter includes a target spindle rotational speed, an incomplete screw portion region machining time, a target spindle acceleration / deceleration, and an upper limit value of the machining length of the incomplete screw portion, When the machining length is equal to or less than the upper limit value, the control means stabilizes the spindle speed in the effective thread area according to the target spindle speed, and then adjusts the target spindle in the incomplete thread area. It is characterized in that the spindle rotational speed is changed so as to gradually decrease based on the speed.

  The invention of claim 9 is the target target spindle speed to be reached in the incomplete thread portion region in which the machining length related parameter is smaller than the target spindle speed adopted in the effective thread portion in claim 7, An incomplete thread portion region machining time, a target spindle acceleration / deceleration and an upper limit value of the machining length of the incomplete thread portion, and the control means, when the machining length is equal to or less than the upper limit value, in the effective thread portion region After controlling the spindle speed to be constant according to the spindle speed, the spindle speed is gradually reduced in the effective thread area and the incomplete thread area based on the target spindle acceleration / deceleration. And the control is performed toward the target spindle speed.

  The invention of claim 10 is directed to claim 7, wherein the machining length related parameter is a target spindle revolution speed to be reached in an incomplete thread section area that is smaller than a target spindle revolution speed employed in an effective thread section, The control means includes an incomplete thread portion region machining time and an upper limit value of the incomplete thread portion machining length. When the machining length is equal to or less than the upper limit value, the control means responds to the target spindle speed in the effective thread portion region. The spindle rotational speed is controlled to be constant, and then the spindle rotational speed is changed so as to gradually decrease to reach the target spindle rotational speed. It is characterized in that it is constant at the spindle speed based on the above.

  In this specification, the main shaft speed is used. However, since the main shaft speed is the same as the main shaft speed, the main shaft speed is decelerated (decreased). ing.

Further, the “target spindle speed” used in the present specification is a preset value, which is the spindle speed used when the spindle speed is controlled to be constant in the effective screw region. .
The “reached target spindle rotational speed” is a spindle rotational speed that is a target value that is reached in the incomplete thread portion region.

  The effective thread area means the range of movement of the machining tool when machining the part that becomes the effective thread part of the workpiece, and the incomplete thread area is when machining the part that becomes the incomplete thread part of the workpiece. This means the movement range of the machining tool.

  According to the first aspect of the present invention, in order to make the spindle rotational speed when machining the incomplete thread portion smaller than the spindle rotational speed when machining the effective thread portion, the effective thread portion and the incomplete thread portion have been conventionally used. The length of the incomplete thread portion can be shortened as compared with the case where the main shaft rotation speed is the same. In addition, there is no restriction on cutting conditions due to incomplete thread, and the spindle speed when machining the effective thread can be increased compared to machining the incomplete thread, reducing the machining time of the effective thread, The processing time for threading can be shortened. Furthermore, according to the first aspect of the present invention, there is an effect that the spindle override during screw machining, which has not been possible conventionally, can be changed.

  According to the second aspect of the present invention, at least in the incomplete screw portion region among the effective screw portion region and the incomplete screw portion region, the above effect can be easily achieved by changing the spindle rotational speed so as to be gradually reduced. Can be realized.

According to the invention of claim 3, the effective screw portion and the incomplete screw portion can have the same screw pitch.
According to the invention of claim 4, the spindle speed is controlled to be constant in the effective thread area, and the spindle speed is gradually changed in the incomplete thread area to change gradually. The effect can be easily realized.

  According to the invention of claim 5, after the main shaft rotation speed is controlled to be constant in the effective screw portion region, the main shaft rotation number is controlled to be gradually decreased. In the incomplete screw portion region, the effective screw portion is controlled. The effect of claim 1 can be easily realized by continuously changing from the region so as to gradually decrease the spindle rotational speed.

  According to the invention of claim 6, after the main shaft rotation speed is controlled to be constant in the effective screw portion region, the main shaft rotation number is controlled to gradually decrease. In the incomplete screw portion region, the effective screw portion region is controlled. The effect of claim 1 can be easily realized by performing control so that the main shaft rotation speed is lower than the main shaft rotation speed constant.

  According to the invention of claim 7, the effective thread portion region and the incomplete thread portion are incomplete according to the relationship between the machining length of the incomplete thread portion and the upper limit value of the machining length of the incomplete thread portion included in the machining length related parameter. The main shaft rotation speed is controlled to be constant in the thread region, or the control according to any one of claims 4 to 6 is performed. In this case, when the control according to any one of claims 4 to 6 is performed, the effect of claim 1 can be easily realized.

  According to the invention of claim 8, when the machining length of the incomplete screw portion is equal to or less than the upper limit value of the machining length of the incomplete screw portion, the spindle rotation speed is constant in the effective screw portion region according to the target spindle rotation speed. After that, the effect of claim 1 can be easily realized by changing the spindle rotational speed so as to gradually decrease based on the target spindle acceleration / deceleration in the incomplete thread portion region.

  According to the invention of claim 9, when the machining length of the incomplete screw portion is equal to or less than the upper limit value of the machining length of the incomplete screw portion, the spindle rotation speed is made constant according to the target spindle rotation speed in the effective screw portion region. Thereafter, the effect of the first aspect can be easily realized by changing the main shaft rotational speed so as to gradually decrease in the effective thread portion region and the incomplete thread portion region, and controlling toward the ultimate target main shaft rotational speed. .

  According to the invention of claim 10, when the machining length of the incomplete thread portion is equal to or less than the upper limit value of the machining length of the incomplete thread portion, the spindle speed is made constant in the effective thread area in accordance with the target spindle speed. After that, the spindle speed is gradually decreased to control to reach the target spindle speed, and the spindle speed based on the target spindle speed is made constant in the incomplete thread region. The effect of item 1 can be easily realized.

Hereinafter, an embodiment in which the threading device of the present invention is embodied in a numerically controlled lathe 10 will be described with reference to FIGS.
As shown in FIG. 1, the numerically controlled lathe 10 has a main shaft 20 that is rotatable about the Z axis, and a claw 30 is formed on the main shaft 20 such that its center coincides with the main shaft 20. The main shaft 20 and the main shaft 20 are rotatably provided. A work W to be machined with a screw is gripped and fixed to the claw 30 in such a manner that the work W can rotate about the Z axis, which is the rotation axis of the main shaft 20. A main shaft motor 230 that can rotate the main shaft 20 is connected to the main shaft 20. The main shaft motor 230 corresponds to main shaft driving means. Further, an angle detector 122 composed of a pulse encoder or the like that is a rotation detector of the main shaft 20 is attached to the main shaft 20. The angle detector 122 generates a pulse signal every time the spindle motor 230 rotates by a certain angle, and feeds it back to the spindle controller 170. The main shaft 20 including the main shaft motor 230 and the claw 30 is disposed on a bed (not shown).

  The turret driving mechanism 300 includes a Z-axis feed motor 320, a feed screw 330, and a saddle 310 for moving the saddle 310 in the Z-axis direction (the horizontal direction in FIG. 1 and parallel to the axis of the main shaft 20). An X-axis feed motor 350 and a feed screw 360 for moving the provided tool post 340 in the X-axis direction (vertical direction in the figure) are configured. The Z-axis direction corresponds to the first axis direction, and the X-axis direction corresponds to the second axis direction orthogonal to the Z-axis direction. The X-axis feed motor 350 and the Z-axis feed motor 320 are mounted with rotary encoders 124X and 126Z as X-axis position and Z-axis position detectors, respectively, and the X-axis position and Z-axis position of the machining tool 400 by both rotary encoders. Can be detected. The Z-axis feed motor 320 corresponds to the first drive means, and the X-axis feed motor 350 corresponds to the second drive means.

  A thread cutting tool, that is, a processing tool 400 is detachably mounted on the tool post 340. The numerically controlled lathe 10 is provided with an NC device 100 as a threading control device that can control and drive the spindle 20 and the processing tool 400, and the NC device 100 includes a CPU as shown in FIG. A main control unit 110 is included. The main control unit 110 corresponds to control means and machining length calculation means. The main control unit 110 includes an input unit 120, an X axis control unit 130, a Z axis control unit 140, an interpolation control unit 150, a main axis control unit 170, a machining program analysis unit 180, an operation panel 185, a display unit 187, a tape reader 190, A storage unit (memory) 195 and the like are connected. The input unit 120 is connected to the rotary encoders 124X and 126Z of the tool post 340 and the angle detector 122 of the spindle 20 respectively. In FIG. 1, for convenience of explanation, a part of the configuration of the NC device 100 is omitted and is not shown. However, as shown in FIG. 2, the X-axis control unit 130 is supplied with an X-axis feed via a drive circuit 132. A motor 350 is connected. A Z-axis feed motor 320 is connected to the Z-axis controller 140 via a drive circuit 142. Further, the spindle motor 230 is connected to the spindle controller 170 via a drive circuit 172.

  The X-axis control unit 130 controls the rotation of the X-axis feed motor 350 via the drive circuit 132 based on the output control signal, and feeds back a pulse signal having a frequency proportional to the rotation speed of the feed screw 360 from the rotary encoder 124X. Enter as.

  On the other hand, the Z-axis control unit 140 controls the rotation of the Z-axis feed motor 320 by the output control signal, and inputs a pulse signal having a frequency proportional to the rotation speed of the feed screw 330 from the rotary encoder 126Z as a feedback signal. Has been.

  The interpolation control unit 150 receives the execution data for one block generated by the spindle control unit 170, the X-axis control unit 130, and the Z-axis control unit 140, and calculates the movement amount of each axis per unit time. The spindle control unit 170, the X-axis control unit 130, and the Z-axis control unit 140 are based on the movement amount of each axis per unit time calculated by the interpolation control unit 150, respectively. The X-axis feed motor 350 can be driven by synchronous interpolation control. The spindle control unit 170 and the Z-axis control unit 140 perform synchronous interpolation on the spindle motor 230 and the Z-axis feed motor 320, respectively, based on the movement amount of each axis per unit time calculated by the interpolation control unit 150. It can be driven by control.

  More specifically, in the effective screw region described later, the control of synchronous interpolation of the rotation of the spindle 20, the X-axis feed, and the Z-axis feed is performed based on the control command of the main control unit 110. This is performed via the X-axis control unit 130 and the Z-axis control unit 140. In addition, in the incomplete thread portion region described later, the synchronous interpolation control for the rotation of the main shaft 20, the X-axis feed, and the Z-axis feed is performed based on the control command of the main control unit 110, This is performed via the X-axis control unit 130 and the Z-axis control unit 140. Note that, in the incomplete thread region described later, synchronous interpolation control for the rotation of the main shaft 20 and the Z-axis feed is performed based on the control command of the main control unit 110 and the Z-axis control. It may be performed via the unit 140.

  The storage unit 195 stores data input by an input unit (not shown), various data generated by the interpolation control unit 150, and various programs. The operation panel 185 includes a group of keys for inputting various data and inputting operations. The display unit 187 is a display device configured from a liquid crystal display device, a CRT, or the like.

  Then, under the control of the NC device 100, the tool post driving mechanism 300 is driven, and the processing tool 400 attached to the tool post 340 is moved in the X-axis direction and the Z-axis direction, and is held by the claw 30 of the spindle 20. The workpiece W is rotated and processed.

  In the example shown in the drawing, for convenience of explanation, only one processing tool 400 is attached to the tool post 340. However, the present invention is not limited to this form. For example, a turret tool post is generally used for this type of device, and a number of tools are radially formed around it, such as various types of outer diameter cutting tools, inner diameter cutting tools, thread cutting tools, parting tools, etc. A drill or the like which is a rotary tool is attached, and any one of them can be selected and used. Therefore, also in this embodiment, it is assumed that the tool can be automatically changed during execution of the thread cutting program using the turret tool post.

(Operation of the embodiment)
Next, the operation of the numerically controlled lathe 10 of this embodiment will be described. 3 to 4 are flowcharts for determining the Z-axis feed speed pattern performed in the threading process executed by the NC apparatus 100. Before the threading process, a start button (not shown) on the operation panel 185 is operated. Then, it is executed by the main control unit 110. In addition, although this embodiment demonstrates the thread cutting process of a single thread | thread, it is not limited to the number of threads.

(S10)
In S10, when the material of the workpiece W is input by operating the operation panel 185, the parameters stored in the storage unit 195 are read according to the workpiece W material. That is, when the material of the workpiece W is selected on the operation panel 185, the parameters corresponding to the material are uniquely read from the database stored in the storage unit 195.

Specifically, a minimum peripheral velocity V ₀ which incomplete thread portion _(mm / min), the spindle acceleration A _{s (rev} / min ²⁾ in the threading, X-axis feedrate clamp value F _{x (mm} / min), X-axis acceleration / deceleration time constant T _x (sec) is read. These values are parameters serving as a basis for calculating the incomplete thread length (equivalent to the machining length of the incomplete thread) later. Spindle acceleration rate A _s is equivalent to the target spindle acceleration rate.

The minimum peripheral speed V ₀ (mm / min) of the incomplete thread, the spindle acceleration / deceleration speed A _s (rev / min ² ), and the X-axis feed speed clamp value F _x (mm / min) in thread cutting are selected. This is also the processing condition of the W material.

In S20, the thread cutting program is read from the tape reader 190 or the like. The thread cutting program includes data relating to a screw to be formed in advance, and this data is read. Specifically, the data relating to the screw to be formed includes the X coordinate value X (mm) of the screw end point, the Z coordinate value Z (mm) of the screw end point, the thread height K (mm), and the lead of the screw. F (mm), target spindle speed S (min ⁻¹ ), upper limit value J (mm) of incomplete thread length, and effective thread length R (corresponding to the working length of the effective thread). The value is a fixed value. The screw end point is the end point of the incomplete screw portion.

  In S30, the machining time ΔT (incomplete thread portion region machining time) for the incomplete thread portion region is calculated by the following equation.

Ｓ４０では、不完全ねじ部領域の主軸最低回転数Ｓ_０の算出が次式にて行われる。

In S40, the calculation of the spindle minimum rotational speed S ₀ of the incomplete thread portion region is performed by the following expression.

Ｓ５０では、不完全ねじ部長さＪ_１の算出が次式にて行われる。

In S50, incomplete thread portion for calculating the length J ₁ is performed by the following expression.

Ｓ６０では、Ｓ５０で算出された不完全ねじ部長さＪ_１と、上限値Ｊとの大小関係の判定が行われる。Ｊ_１＞Ｊの場合は、Ｓ７０に移行され、Ｊ_１≦Ｊの場合は、Ｓ１４０でＺ軸送り速度パターンＡが選択されて、このルーチンが終了される。

In S60, the incomplete thread portion length J ₁ calculated in S50, the determination of the magnitude relationship between the upper limit value J is performed. If J ₁ > J, the process proceeds to S70. If J ₁ ≦ J, the Z-axis feed speed pattern A is selected in S140, and this routine ends.

In S70, the incomplete thread length J ₂ (<J ₁ ) is calculated by the following equation. Various data (ΔT, F, S, A _s ) used in “Equation 4” of S70 correspond to machining length related parameters.

Ｓ８０では、Ｓ７０で算出された不完全ねじ部長さＪ_２と、上限値Ｊとの大小関係の判定が行われる。Ｊ_２＞Ｊの場合は、Ｓ９０に移行され、Ｊ_２≦Ｊの場合は、Ｓ１５０でＺ軸送り速度パターンＢが選択されて、このルーチンが終了される。

In S80, the incomplete thread portion length J ₂ calculated in S70, the determination of the magnitude relationship between the upper limit value J is performed. If J ₂ > J, the process proceeds to S90. If J ₂ ≦ J, the Z-axis feed speed pattern B is selected in S150, and this routine is terminated.

In S90, the incomplete thread length J ₃ (<J ₂ <J ₁ ) is calculated by the following equation. Various data (ΔT, F, S ₀ , A _s ) used in the calculation of “Equation 5” correspond to machining length related parameters.

Ｓ１００では、Ｓ９０で算出された不完全ねじ部長さＪ_３と、上限値Ｊとの大小関係の判定が行われる。Ｊ_３＞Ｊの場合は、Ｓ１１０に移行され、Ｊ_３≦Ｊの場合は、Ｓ１６０でＺ軸送り速度パターンＣが選択されて、このルーチンが終了される。

In S100, the incomplete thread portion length J ₃ calculated in S90, the determination of the magnitude relationship between the upper limit value J is performed. If J ₃ > J, the process proceeds to S110. If J ₃ ≦ J, the Z-axis feed speed pattern C is selected in S160, and this routine is terminated.

In S110, the incomplete thread length J ₄ (<J ₃ <J ₂ <J ₁ ) is calculated by the following equation. Various data (ΔT, F, S ₀ ) used in “Equation 6” of S110 corresponds to machining length related parameters.

Ｓ１２０では、Ｓ１１０で算出された不完全ねじ部長さＪ_４と、上限値Ｊとの大小関係の判定が行われる。Ｊ_４＞Ｊの場合は、Ｓ１３０に移行され、Ｊ_４≦Ｊの場合は、Ｓ１７０でＺ軸送り速度パターンＤが選択されて、このルーチンが終了される。

In S120, the incomplete thread portion length _{J 4} calculated in S110, the determination of the magnitude relationship between the upper limit value J is performed. If J ₄ > J, the process proceeds to S130. If J ₄ ≦ J, the Z-axis feed speed pattern D is selected in S170, and this routine is terminated.

  In S130, an alarm (warning text) is displayed on the display unit 187, and this routine ends. In other words, the machining length of the incomplete thread calculated based on the currently assigned data exceeds the upper limit, and a warning is given that threading machining based on the currently assigned data is not preferable. It is granted.

Next, the Z-axis feed speed patterns A to D selected in S140 to S170 will be described, and the spindle speed when each pattern is selected will be described.
(Z-axis feed rate pattern A)
FIG. 7A shows a Z-axis feed rate pattern A, and the Z-axis feed rate is maintained at a constant value in both the effective screw portion region and the incomplete screw portion region. Note that the Z-axis feed speed in this case is the product of the target spindle speed S and the screw lead F.

  In the Z-axis feed rate pattern A, t1 indicates the cutting start time at the start point of the effective thread region (the same applies hereinafter). Further, ta (> t1) indicates the cutting start time at the starting point of the incomplete thread portion.

  When this Z-axis feed speed pattern A is selected, in the effective screw region, the main control unit 110 calculates the actual Z-axis position of the machining tool 400 based on the detection signal of the rotary encoder 126Z, and calculates the actual It is determined whether or not the cutting of the effective thread portion is completed based on the Z-axis position. When the actual Z-axis position of the processing tool 400 is the Z-axis position of the end point of the effective thread part, the main control unit 110 determines that the cutting process of the effective thread part is completed, and the cutting process of the effective thread part is completed. From the time point ta, the main control unit 110 controls the main shaft control unit 170, the X-axis control unit 130, and the Z-axis control unit 140 so as to start cutting the incomplete thread portion.

  When the Z-axis feed speed pattern A is selected, as shown in FIG. 8A, both the effective screw portion region and the incomplete screw portion region are controlled by the main control unit 110 so that the main shaft 20 is the target main shaft. It is rotated at a rotational speed S (fixed value), that is, at a constant rotational speed (spindle rotational speed pattern A1).

  In the effective thread area, the rotation of the spindle 20 and the feed of the X and Z axes are controlled by synchronous interpolation by the spindle controller 170, the X axis controller 130, the Z axis controller 140, and the interpolation controller 150. The In the incomplete thread portion region, the rotation of the spindle 20 and the feed of the X axis and the Z axis are controlled by synchronous interpolation by the spindle controller 170, the X axis controller 130, the Z axis controller 140, and the interpolation controller 150. In this way, the spindle 20 and the Z-axis feed are synchronously interpolated so that the spindle speed is constant and the Z-axis feed speed is constant in any region, so that the screw pitch P is Processed to be the same.

(Z-axis feed rate pattern B)
FIG. 7B shows a Z-axis feed rate pattern B, and the Z-axis feed rate is held at a constant value in the effective screw portion region. The Z-axis feed speed in this region is the product of the target spindle speed S and the screw lead F. In addition, the entire Z axis region, that is, from the end point of the effective screw region (= start point of the incomplete screw region) to the end point of the incomplete screw region (region during machining time ΔT) As shown in FIG. 7B, the feed speed is set so as to gradually decelerate with an inclination A _s · F (product of spindle acceleration / deceleration and screw lead).

In the Z-axis feed rate pattern B shown in FIG. 7B, tb (= ta) indicates the cutting start point of the starting point of the incomplete thread portion.
When this Z-axis feed speed pattern B is selected, in the effective screw region, the main control unit 110 calculates the actual Z-axis position of the machining tool 400 based on the detection signal of the rotary encoder 126Z, and calculates the actual Whether or not the cutting of the effective thread portion has been completed is determined based on the Z-axis position in the same manner as when the Z-axis feed speed pattern A is selected. When the actual Z-axis position of the processing tool 400 is the Z-axis position of the end point of the effective thread part, the main control unit 110 determines that the cutting process of the effective thread part is completed, and the cutting process of the effective thread part is completed. From the time point tb, the main control unit 110 controls the main shaft control unit 170, the X-axis control unit 130, and the Z-axis control unit 140 so as to start cutting the incomplete thread portion.

When the Z-axis feed speed pattern B is selected, the main shaft 20 is controlled by the main control unit 110 in the effective screw region as shown in FIG. That is, it is rotated at a constant rotational speed. In addition, in the entire area of the incomplete thread area, the spindle speed gradually increases with a slope A _s (spindle acceleration / deceleration) during the machining time ΔT from the end point of the effective thread area as shown in FIG. 8B. (Spindle speed pattern B1). In this case, the target value to which the main shaft rotation speed finally goes is a value that is larger than the minimum main shaft rotation speed S ₀ as shown in FIG.

  In the effective thread area, the rotation of the spindle 20 and the feed of the X and Z axes are controlled by synchronous interpolation by the spindle controller 170, the X axis controller 130, the Z axis controller 140, and the interpolation controller 150. The In the incomplete thread region, the main shaft controller 170, the X-axis controller 130, the Z-axis controller 140, and the interpolation controller 150 rotate the main shaft 20 so that the screw pitch P is the same as the effective thread region. The Z-axis feed is controlled by synchronous interpolation, and the rotation of the spindle 20 and the X-axis feed are controlled by synchronous interpolation.

(Z-axis feed rate pattern C)
FIG. 7C shows a Z-axis feed rate pattern C, and the Z-axis feed rate is held at a constant value in a part of the region starting from the start point of the effective screw portion region. The Z-axis feed speed in this region is the product of the target spindle speed S and the screw lead F. Further, in the part of the effective thread area, the speed gradually decreases with the inclination A _s · F (product of spindle acceleration / deceleration and screw lead) from the end point of the partial area to the end point of the effective thread area. It is set to be. Furthermore, in the entire area of the incomplete thread portion region, Z axis feed rate, as shown in FIG. 7 (c), gradually decelerated in slope A _s · F (product of spindle acceleration speed and thread lead), Incomplete It is set to reach S ₀ · F (the product of the minimum spindle speed S ₀ and the screw lead F) at the end point of the thread region.

In the Z-axis feed speed pattern C shown in FIG. 7 (c), tc1 starts gradually decelerating from the end point of the above-mentioned partial area at an inclination A _s · F (product of spindle acceleration / deceleration and screw lead). Indicates the time. Furthermore, tc2 (>tc1> t1) indicates the cutting start point of the starting point of the incomplete thread portion.

When reaching tc1 and tc2, the main control unit 110 calculates the Z-axis position (scheduled position) where the machining tool 400 should be positioned based on the arithmetic expression included in the threading machining program in advance. For calculating the planned position, the cutting start time t1, the effective thread length R, the Z-axis feed rate (S · F) of the effective thread area, the inclination A _s · F, the machining time ΔT, and S ₀ · F data (spindle minimum rotational speed S ₀ and the thread of the product of the lead F) is used. Here, the spindle minimum frequency S ₀ corresponds to the final target spindle speed.

In the effective screw region, the main control unit 110 calculates the actual Z-axis position of the processing tool 400 based on the detection signal of the rotary encoder 126Z, and the actual Z-axis position of the processing tool 400 is the planned position. From the time tc1 at which one Z-axis position is reached, cutting is performed while gradually decelerating at an inclination A _s · F (product of spindle acceleration / deceleration and screw lead). In addition, the main control unit 110 decelerates the incomplete screw portion while decelerating at a slope A _s · F (product of the main shaft acceleration / deceleration and screw lead) from the time tc2 when it reaches one Z-axis position which is the remaining planned position. Perform cutting.

Further, when the Z-axis feed speed pattern C is selected, in a part of the region starting from the starting point of the effective screw portion region as shown in FIG. During tc1, the spindle rotates at a target spindle speed S (fixed value), that is, the spindle 20 rotates at a constant speed. Further, Tc1～tc2, and the entire area of the incomplete thread portion region, i.e., as shown in FIG. 8 (c), the main control unit 110, reaches the target spindle spindle speed in the slope _{A s} (spindle acceleration rate) toward the spindle minimum rotational speed S ₀ is the rotation speed is decelerated gradually (spindle speed pattern C1).

Further, in the effective screw portion region, the rotation of the spindle 20 and the feed of the X axis and the Z axis are controlled by synchronous interpolation by the spindle control unit 170, the X axis control unit 130, the Z axis control unit 140, and the interpolation control unit 150. . In the incomplete thread portion region, the rotation of the spindle 20, the feed of the X axis and the feed of the Z axis are controlled by synchronous interpolation by the spindle control unit 170, the X axis control unit 130, the Z axis control unit 140 and the interpolation control unit 150. The Then, in a part of the effective screw region, the spindle 20 and the Z-axis feed are synchronously interpolated so that the spindle speed is constant and the Z-axis feed speed is constant, and the screw pitch P is the same. To be processed. Further, in the region where machining cutting is performed while decelerating with the inclination A _s · F (product of spindle acceleration / deceleration and screw lead), the screw pitch P is the same as the partial region of the effective screw region. The rotation of the spindle 20 and the Z-axis feed are controlled by synchronous interpolation.

(Z-axis feed rate pattern D)
FIG. 7D shows a Z-axis feed rate pattern D, and the Z-axis feed rate is held at a constant value in a partial region starting from the start point of the effective screw portion region. Note that the Z-axis feed speed in this case is the product of the target spindle speed S and the screw lead F. In addition, in a part of the effective thread part region, from the end point of the part of the part to the end point of the effective thread part region, the speed gradually decreases with an inclination A _s · F (product of spindle acceleration / deceleration and screw lead). When the end point of the effective thread area is reached, the Z-axis feed speed is set to a speed of _S0 · F (the product of the minimum spindle speed _S0 and the screw lead F). Has been. Furthermore, in the entire area of the incomplete thread portion, the Z-axis feed speed is kept constant at S ₀ · F (the product of the minimum spindle speed S ₀ and the screw lead F) as shown in FIG. Retained.

In the Z-axis feed speed pattern D shown in FIG. 7 (d), td1 starts gradually decelerating from the end point of the partial area described above with the slope A _s · F (product of spindle acceleration / deceleration and screw lead). Indicates the time. Furthermore, td2 (>td1> t1) indicates the cutting start point of the starting point of the incomplete thread portion.

When td1 and td2 are reached, the main control unit 110 calculates the Z-axis position (scheduled position) where the machining tool 400 should be located based on an arithmetic expression included in advance in the threading program. For calculating the planned position, the cutting start time t1, the effective thread length R, the Z-axis feed speed (S · F) of the effective thread area, the inclination A _s · F, and the S ₀ · F (spindle minimum rotation) The data of the number S ₀ and the screw lead F) is used.

In the effective screw region, the main control unit 110 calculates the actual Z-axis position of the processing tool 400 based on the detection signal of the rotary encoder 126Z, and the actual Z-axis position of the processing tool 400 is the planned position. from the time td1 reaching the Z-axis position of a hand, performs cutting is decelerated gradually slope a _s · F (product of spindle acceleration speed and thread lead).

Actual Z-axis position of the working tool 400 is, from the predetermined position at which one of Z-axis time td2 reaching position, the Z-axis feed rate, S 0 _· F (spindle minimum rotational speed S ₀ and thread lead F The product is cut at an incomplete threaded portion at a constant speed.

  When the Z-axis feed speed pattern D is selected, in a part of the region starting from the starting point of the effective screw portion region as shown in FIG. Is rotated at a target spindle speed S (fixed value), that is, the spindle 20 is rotated at a constant speed.

In addition, from td1 to td2, as shown in FIG. 8D, the main controller 110 changes the spindle speed from the end point (time point td1) of the effective screw region to the end point of the effective screw region. gradually decelerated toward the slope a _s spindle minimum rotational speed S ₀ is reached the target spindle speed in _(spindle acceleration rate). Further, the main control unit 110 makes the main shaft rotation speed constant at the minimum main shaft rotation speed S ₀ in the incomplete thread portion region (main shaft rotation speed pattern D1).

  Further, in the effective screw portion region, the rotation of the spindle 20 and the feed of the X axis and the Z axis are controlled by synchronous interpolation by the spindle control unit 170, the X axis control unit 130, the Z axis control unit 140, and the interpolation control unit 150. . In the incomplete thread portion region, the rotation of the spindle 20, the feed of the X axis and the feed of the Z axis are controlled by synchronous interpolation by the spindle control unit 170, the X axis control unit 130, the Z axis control unit 140 and the interpolation control unit 150. The

Then, in a part of the effective screw region, the spindle 20 and the Z-axis feed are synchronously interpolated so that the spindle speed is constant and the Z-axis feed speed is constant, and the screw pitch P is the same. To be processed. Further, in the region where machining cutting is performed while decelerating with the inclination A _s · F (product of spindle acceleration / deceleration and screw lead), the screw pitch P is the same as the partial region of the effective screw region. The rotation of the spindle 20 and the Z-axis feed are controlled by synchronous interpolation. Further, in the incomplete thread region, the rotation of the main shaft 20 and the Z-axis feed are controlled by synchronous interpolation by the main shaft control unit 170, the Z-axis control unit 140, and the interpolation control unit 150, and the screw pitch P is effective. It is processed to be the same as the thread region.

  As described above, when one of the Z-axis feed rate patterns is selected, the main control unit 110 continues to select the selected Z-axis feed rate patterns A to D and the Z-axis feed rate patterns based on the thread cutting program. Thread cutting is performed on the workpiece W with the spindle rotation speed patterns A1 to D1 corresponding to the shaft feed speed pattern.

  Hereinafter, for convenience of explanation, it is assumed that the Z-axis feed speed pattern C is selected. When threading is started, the main control unit 110 controls the main shaft motor 230 via the main shaft control unit 170 and the drive circuit 172 so that the main shaft rotation speed becomes the target main shaft rotation speed S.

  When the spindle rotational speed reaches the target spindle rotational speed S, the main control unit 110 outputs a control command to the Z-axis control unit 140 and the X-axis control unit 130, and from the position where the machining tool 400 stands by, the work W In the area of the approach portion up to the machining start point, the feed in the X-axis direction and the feed in the Z-axis direction are accelerated to the just before the effective thread portion while synchronously interpolating (see FIGS. 5A to 5C). . 5A to 5C show time charts of the actual spindle speed, the Z-axis feed speed, and the X-axis feed speed in the case of the Z-axis feed speed pattern C. FIG.

In the effective screw part region (t1 to tc2), the rotation of the spindle 20 and the feed of the Z axis and the X axis are synchronously interpolated by the spindle controller 170, the X axis controller 130, the Z axis controller 140, and the interpolation controller 150. It is controlled by. Then, as shown in the figure, between t1 and tc1, according to the Z-axis feed speed pattern C, the spindle speed is controlled based on the target spindle speed S and is kept constant. It followed, during tc1~tc2 is the spindle control section 170, gradually decelerated in _{A s} (spindle deceleration) slope spindle speed.

Further, in the incomplete thread portion region (machining time ΔT), the rotation of the main shaft 20, the feed of the X axis, and the feed of the Z axis are performed based on the control command of the main control portion 110, and the main shaft control portion 170 and the X axis control portion 130. The Z-axis control unit 140 and the interpolation control unit 150 are controlled by synchronous interpolation. Further, in this region, the spindle control unit 170 gradually reduces the spindle rotational speed with a slope A _s (spindle acceleration / deceleration) based on the control command of the main control unit 110. On the other hand, in the incomplete thread region, the X-axis feed motor 350 is driven and controlled via the X-axis control unit 130 based on the control command of the main control unit 110, and as shown in FIG. By changing the axial feed speed and moving the tool post 340, the machining tool 400 is rounded up in the direction away from the workpiece W, and the rounding up is completed at the end point of the incomplete thread portion region.

  From the time when the end point of the incomplete thread portion region is exceeded, as shown in FIG. 5A, the spindle control unit 170 again sets the spindle rotational speed to the initial speed based on the control command of the main control unit 110. The spindle motor 230 is accelerated so as to reach the target spindle speed S. On the other hand, based on the control command of the main control unit 110, the Z-axis control unit 140 and the X-axis control unit 130 decelerate by non-interpolation so that the Z-axis feed speed and the X-axis feed speed become zero, and the X-axis feed The motor 350 and the Z-axis feed motor 320 are controlled to stop.

  As shown in FIG. 5C, the X-axis feed speed rises at the approach portion between 0 and t1, and becomes a constant speed between t1 and tc1. Between tc1 and tc2, the motor gradually decelerates in synchronization with the decrease in the spindle speed, and after tc2, the speed is increased to a predetermined speed, and after maintaining the predetermined speed for a certain time, 0 (mm / min) To slow down. As a result, as shown in FIG. 11, the formed effective screw portion has a tapered shape in which the outer diameter of the distal end is small and the outer diameter of the proximal end is large.

  In the above description, the threading process using the Z-axis feed speed pattern C has been described. However, the remaining patterns have been described in the above-described items of the respective patterns, and thus description thereof will be omitted.

The features of this embodiment are as follows.
(1) FIG. 6 shows an interpolation pattern of the Z-axis position and the main shaft rotation angle performed by the control of the main control unit 110, where the vertical axis is the main shaft rotation angle (rad) and the horizontal axis is the Z-axis position. In the case of the present embodiment, not only the effective thread area but also the incomplete thread area, the rotation of the spindle 20 and the Z-axis feed are synchronously interpolated to make the pitch P constant. Let it be constant. The relationship between the screw lead L (the distance moved in the axial direction of the screw when the screw is rotated once) and the pitch P is L = P in the case of a single thread, and in the case of a double thread, L = 2P. That is, L = nP, where n is the number of threads. In this embodiment, it is threading of a single thread.

(2) FIG. 9A is a time chart of the Z-axis feed speed in the case of conventional threading, and FIG. 10 is a time chart of a conventional incomplete thread portion region. Conventionally, when the _{S 1} and the spindle rotation speed, the Z-axis feed rate _{S 1} · F, effective thread area of the processing time (t2-t1), and incomplete threaded region of the processing time (t3-t2) In, it is made constant. That is, in the effective screw portion region (between t1 and t2) and the incomplete screw portion region (between t2 and t3), the spindle speed is made constant.

L ₁ is the effective thread length, and is represented by L ₁ = S ₁ · F * (t2−t1). L ₂ is incomplete thread portion length of the conventional thread _cutting, is expressed by _{L 2 = S 1 · F *} (t3-t2).

Conventionally, the spindle speed is kept constant even in the area where the effective thread part and incomplete thread part are machined. If the incomplete thread part becomes longer than the drawing instruction (design value), the spindle The rotational speed is lowered below the appropriate value for cutting so that the incomplete thread portion does not become longer. For example, as shown in FIG. 10, S ₁ · F needs to be lowered as shown in S ₁₁ · F (<S ₁ · F) or S ₁₂ · F (<S ₁ · F). Note that S ₁₁ (<S ₁ ) and S ₁₂ (<S ₁₁ ) are spindle speeds, respectively. In this case, when the incomplete thread portion region is machined at the spindle speed at S ₁₁ and S ₁₂ , the incomplete thread lengths L ₂₁ and L ₂₂ in that case are L ₂₁ = S ₁₁ · F * (t 3 −t 2). ), L ₂₂ = S ₁₂ · F * (t3−t2). Therefore, L ₂ > L ₂₁ > L ₂₂ is satisfied.

  However, if the spindle speed is reduced in this way, machining will be performed at the reduced spindle speed even in the effective thread area, so the machining time including the effective thread part and incomplete thread part will become longer, and the effective thread part will become longer. There is a problem that the processing time including the partial region and the incomplete threaded region becomes long. The effective thread length is generally several times longer than the incomplete thread length, and the effective thread area has a longer machining time, that is, a longer total machining time. This is not preferable in terms of processing efficiency.

FIG. 9B is a time chart of the Z-axis feed speed of the Z-axis feed speed pattern C of the present embodiment.
In the present embodiment, the Z-axis feed rate is kept constant from the cutting start time t1 to tc1 in the effective screw portion region. In this case, the Z-axis feed speed is set to S ₂ · F which is faster than the conventional S ₁ · F. Until tc1~t4 (= tc2) ~t5 (end point of the incomplete thread portion region) is gradually decelerated by the slope _{A s} · (spindle acceleration rate). In this case, the spindle speed also has the pattern shown in FIG. In this case, since the spindle 20 is rotated at a spindle speed S ₂ faster than the conventional S _1, the machining time for the effective thread region can be shortened, and the machining time for the effective thread region and the incomplete thread region can be shortened. There is an effect that can be done.

  On the other hand, in the incomplete thread area, the incomplete thread length is conventionally set to the same constant spindle speed as in the effective thread area and the incomplete thread area in order to make it smaller than the spindle speed in the effective thread area. This can be shortened compared to when cutting.

Incidentally, incomplete thread portion length _{L 3} shown in FIG. 9 (b) corresponds to _{J 3.}
(3) Even when the Z-axis feed speed pattern B is selected and the spindle rotational speed is controlled by the spindle rotational speed pattern B1, the effects (1) and (2)) are provided for the same reason as described above. Play.

Even when the Z-axis feed speed pattern D is selected and the spindle rotation speed is controlled by the spindle rotation speed pattern D1, the effects (1) and (2) are obtained for the same reason as described above.
In addition, embodiment of this invention is not limited to the said embodiment. For example, the following may be used.

(1) In the embodiment, the Z-axis feed speed pattern C, and was the same as the inclination _{A s} · F in slope machining time ΔT between Tc1～tc2, as indicated by the dotted line shown in FIG. 5 (b) In addition, different inclinations may be set. In this case, since the main shaft 20 is also controlled by synchronous interpolation by the main control unit 110, the main shaft rotation speed is similarly changed.

  (2) In the embodiment, the tool post 340 is movable in the X-axis direction and the saddle 310 is movable in the Z-axis direction. However, the spindle 20 is movable in the Z-axis direction and the X-axis direction, respectively. You may provide the 1st drive means (for example, motor) and the 2nd drive means (for example, motor) which drive to these directions. Then, the first drive unit and the second drive unit may be controlled in the same manner as in the above embodiment by the main control unit 110 as the control unit.

  (3) The spindle 20 may be movable in the Z-axis direction, the saddle 310 may be omitted, and the tool post 340 may be disposed so as to be movable in the X-axis direction. Then, first driving means (for example, a motor) for driving the spindle 20 in the Z-axis direction is provided, and second driving means (for example, an X-axis feed motor 350) for driving the tool post 340 in the X-axis direction is provided. Then, the first drive unit and the second drive unit may be controlled in the same manner as in the above embodiment by the main control unit 110 as the control unit.

  (4) Further, the saddle 310 may be movable in the Z-axis direction, and the main shaft 20 may be disposed so as to be movable in the X-axis direction. Then, first driving means (for example, Z-axis feed motor 320) for driving the saddle 310 in the Z-axis direction is provided, and second driving means (for example, motor) for driving the main shaft 20 in the X-axis direction is provided. Then, the first drive unit and the second drive unit may be controlled in the same manner as in the above embodiment by the main control unit 110 as the control unit.

  (5) In the said embodiment, although it carried out with the main-axis | shaft rotation speed, the Z-axis feed rate pattern, and the X-axis feed rate pattern which are shown to Fig.5 (a)-(c), FIG.13 (a)-(c). The pattern shown in FIG. 13 (a) to 13 (c), the spindle rotational speed in FIG. 13 (a) and the Z-axis feed rate pattern in FIG. 13 (b) are the same as those in FIGS. 5 (a) and 5 (b). The X-axis feed rate pattern of (c) is different. In the X-axis feed rate pattern of FIG. 13C, the X-axis feed rate is 0 (mm / min) in the approach portion and the effective screw portion, and after increasing to a predetermined speed from tc2, The predetermined speed is decelerated to 0 (mm / min) after a predetermined time has elapsed. As a result, as shown in FIG. 12, in the formed effective screw portion, the outer diameter from the distal end to the proximal end is a straight shape having the same diameter.

1 is a schematic diagram of a numerically controlled lathe 10. FIG. 2 is a block diagram of the NC device 100. FIG. The flowchart of a thread cutting process. The flowchart of a thread cutting process. (A) is a time chart of spindle rotation speed, (b) is a time chart of Z-axis feed speed, and (c) is a time chart of X-axis feed speed. Explanatory drawing which shows the interpolation pattern of a Z-axis and a principal axis. (A)-(d) is explanatory drawing of a Z-axis feed rate pattern. (A)-(d) is explanatory drawing of a spindle speed pattern. (A) is a time chart of the Z-axis feed speed of the conventional thread cutting process, (b) is a time chart of the Z-axis feed speed in this embodiment. The time chart of the Z-axis feed speed in an incomplete thread part. Explanatory drawing at the time of seeing from the front of the workpiece | work in the case of threading of one Embodiment. Explanatory drawing at the time of seeing from the front of the workpiece | work in the case of threading of other embodiment. (A) is a time chart of the spindle speed of another embodiment, (b) is a time chart of a Z-axis feed speed, and (c) is a time chart of an X-axis feed speed. (A) is explanatory drawing at the time of seeing from the front of the workpiece | work in the case of threading, (b) is explanatory drawing at the time of similarly seeing a workpiece | work from the side. (A) is explanatory drawing of the Z-axis feed speed of the conventional conventional threading process, (b) is explanatory drawing of Z-axis feed speed similarly, (c) is explanatory drawing of X-axis feed speed.

Explanation of symbols

10 ... Numerically controlled lathe (threading machine)
20 ... Spindle 110 ... Main control section (control means, machining length calculation means)
170 ... Spindle control unit 230 ... Spindle motor (spindle drive means)
320 ... Z-axis feed motor (first drive means)
350 ... X-axis feed motor (second drive means)
340 ... Tool post 400 ... Processing tool W ... Workpiece

Claims (10)

  A main shaft for holding a workpiece, main shaft driving means for rotating the main shaft, a tool post provided with a processing tool, and a first axial direction in which at least one of the main shaft and the tool post is parallel to the axis of the main shaft First driving means for driving to move to, second driving means for driving at least one of the spindle and the tool post in a second axis direction orthogonal to the first axis direction, and the spindle driving means And control means for controlling and driving the first driving means and the second driving means, respectively, by moving the spindle and the tool rest relative to each other, the tool is held on the spindle by the tool of the tool rest. In a threading apparatus capable of forming a thread having an effective thread part and an incomplete thread part on a workpiece, the control means processes the effective thread part according to a spindle rotational speed when the incomplete thread part is processed. The spindle driving means is controlled to be smaller than the combined spindle speed, and at least the first driving means of the first driving means and the second driving means is controlled by synchronous interpolation with the spindle driving means. A threading device characterized by:   The control means may change the spindle rotational speed so as to gradually decelerate at least in the incomplete screw portion region of the effective screw portion region and the incomplete screw portion region in which the workpiece is processed by the processing tool. The threading device according to claim 1, wherein   The control means includes at least a first drive means among the first drive means and the second drive means so that the pitch of the screw in the effective screw portion region and the pitch of the screw in the incomplete screw portion region are the same. 3. The thread cutting apparatus according to claim 1, wherein the spindle driving means is controlled by synchronous interpolation.   The control means controls the spindle speed to be constant in the effective screw portion region among the effective screw portion region and the incomplete screw portion region that processes the workpiece with the processing tool, and in the incomplete screw portion region, 2. The thread cutting apparatus according to claim 1, wherein the spindle rotational speed is changed so as to gradually decrease.   The control means controls the spindle speed in the effective thread area, which is the effective thread area and the incomplete thread area where the workpiece is processed by the processing tool, and then gradually increases the spindle speed. 2. The threading device according to claim 1, wherein the spindle rotational speed is changed so as to gradually decrease in the incomplete thread portion region continuously from the effective thread portion region. .   The control means controls the spindle speed in the effective thread area, which is the effective thread area and the incomplete thread area where the workpiece is processed by the processing tool, and then gradually increases the spindle speed. 2. The incomplete thread portion region is controlled so as to be constant at a spindle rotational speed that is smaller than a constant spindle rotational speed in the effective thread portion region. Threading machine. A processing length calculation means for calculating a processing length of the incomplete thread portion based on a processing length related parameter,
In accordance with the magnitude relationship between the machining length and the upper limit value of the machining length of the incomplete thread included in the machining length-related parameter, the control means keeps the spindle speed constant in the effective thread area and the incomplete thread area. Or a threading device characterized by performing the control according to any one of claims 4 to 6. The machining length-related parameters include a target spindle speed, an incomplete thread portion region machining time, a target spindle acceleration / deceleration, and an upper limit value of the machining length of the incomplete thread portion,
When the machining length is equal to or less than the upper limit value, the control means stabilizes the spindle speed in the effective thread area according to the target spindle speed, and then adjusts the target spindle in the incomplete thread area. 8. The thread cutting apparatus according to claim 7, wherein the spindle rotational speed is changed so as to gradually decrease based on the speed. The machining length-related parameters are the target spindle speed to be reached in the incomplete thread area that is smaller than the target spindle speed employed in the effective thread, the incomplete thread area machining time, the target spindle acceleration / deceleration And the upper limit of the machining length of the incomplete thread,
When the machining length is equal to or less than the upper limit value, the control means performs control to make the main shaft rotational speed constant in the effective screw portion region according to the target main shaft rotational speed, and then based on the target main shaft acceleration / deceleration The main shaft rotational speed is controlled so as to gradually decrease in the effective screw portion region and the incomplete screw portion region, and control is performed toward the ultimate target main shaft rotational speed. Threading machine. The machining length-related parameters are the target spindle rotational speed to be reached in the incomplete thread area that is smaller than the target spindle speed adopted in the effective thread, the incomplete thread area processing time, and the incomplete thread section. Including the upper limit of the processing length of
When the machining length is equal to or less than the upper limit value, the control means performs control to keep the spindle rotation speed constant in the effective screw region in accordance with the target spindle rotation speed, and then gradually decreases the spindle rotation speed. The control is performed so as to change to reach the target spindle speed, and in the incomplete thread region, the spindle speed based on the target spindle speed is constant. Threading machine.

Images