JPS614637A - Driving control method of center rest device in numerically-controlled lathe - Google Patents

Abstract

PURPOSE:To aim at automation in application and positioning for a center rest device, by letting the center rest device shift to a flat part judged out of a memory of a work flat part table and positioning it thereat when work's overall length is judged as being more than the specified value to the diameter. CONSTITUTION:In time of machining, a main control part 2 calls a machining program PRO out of a machining program memory 7 and outputs it to a mechanism performance control part 10, while this control part 10 drives and controls a tool rest 13 and a spindle 12, but when such machining as using a center rest device 11 is instructed in a certain machining job, the main control part 2 drives and controls this center rest device 11 and positions this device 11 at the specified position. Next, when use of this center rest device 11 is not instructed, the main control part 10 operates and judges it from a diameter D and overall length L of a work blank, and when L>aD is judged so, the center rest device 11 is used whereby chattering to be produced during operation is effectively restrained so that highly accurate machining is securable.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Technical Field of the Invention The present invention relates to a drive control method for a steady rest device installed and used in a numerically controlled lathe for the purpose of preventing chatter of a workpiece.

(a) Technical Field of the Invention Normally, when machining a long bar-shaped workpiece in lathe machining, a steady rest device is used to prevent the bits that occur during machining and to perform highly accurate machining. .

(C), Prior Art and Problems Conventionally, when a steady rest device is used in a numerically controlled lathe, it has been necessary for an operator to manually position it. However, if you try to use the steady rest device during machining, it is extremely difficult to correctly set the steady rest device in the optimal position, and it is actually impossible to operate the steady rest device during machining. Met.

Therefore, operators have no choice but to change cutting conditions, tools, etc. through trial and error to eliminate chatter, and are forced to perform extremely inefficient work.

(d)0Object of the Invention In order to eliminate the above-mentioned drawbacks, the present invention provides a drive control method for a steady rest device in a numerically controlled lathe, which allows the numerically controlled lathe to properly position the steady rest device at a predetermined position. To provide a numerically controlled lathe whose primary purpose is to provide a numerically controlled lathe in which the machine side can determine whether or not a steady rest device can be used without the operator having to give any special instructions regarding the use of the steady rest device in a machining program. A second object of the present invention is to provide a method for controlling the drive of the anti-sway device in the present invention.

(e) 0 Configuration of the invention That is, the present invention provides a memory that stores a workpiece flat part table indicating the position of the flat part during processing of the workpiece,
The contents of the workpiece flat part table are sequentially rewritten in accordance with the progress of machining, and during machining based on the machining program, it is calculated and determined whether the total length of the workpiece is longer than a predetermined length with respect to the diameter of the workpiece. As a result, if it is determined that the length is longer than a predetermined length, the workpiece flat part table in the memory is searched and the workpiece is machined.

The flat part of the workpiece to be machined is determined, and the steady rest device is moved and positioned on the determined flat part to support the workpiece being machined.

(f) 0 Embodiments of the Invention Hereinafter, embodiments of the present invention will be specifically described based on the drawings.

FIG. 1 is a control block diagram showing an example of a numerically controlled lathe to which the drive control method for a steady rest device according to the present invention is applied; FIG. 2 is a side view showing an example of a three-point steady rest device;
The figure is a side view showing an example of a two-point support steady rest device, FIG. 4 is a schematic diagram showing a workpiece flat part table stored in the workpiece flat part shape memory, and FIGS. 5 to 9 are control of the steady rest device. FIG. 10 is a diagram showing the dimensional relationship when determining the encounter point between the tool and the steady rest device in follow-up control.

As shown in FIG. 1, the numerically controlled lathe 1 has a main control section 2, and the main control section 2 is connected via a path line 3 to a keyboard 5, a workpiece flat part shape memory 6, and a machining program memory 7. , steady rest control section 9, mechanism operation control section 10, etc. are connected. Two steady rest devices 1 are installed in the steady rest control unit 9.
The steady rest device 11 supports the workpiece 15 with three support rollers 11a according to the support mode of the workpiece 15, as shown in FIG. There are a three-point support steady rest device that supports the workpiece 15, and a two-point support steady rest device that supports the workpiece 15 with two support rollers lla, as shown in FIG. It should be noted that these steady rest devices 11 can be selectively used as appropriate by attaching them to the bed 16 of the lathe as necessary. Further, the steady rest device 11 is installed on the bed 16 so as to be movable and driven in the Z-axis direction, that is, in the direction perpendicular to the plane of the paper in FIGS. It is also provided so as to be freely drivable in the X-axis direction, which is a direction perpendicular to the X-axis direction.

In addition, the three-point support steady rest device 11 includes a support roller ll.
The three support arms 11b to which a is attached are indicated by arrows A, B
By opening and closing the support arm 11b, it is possible to support the workpiece 15 and prevent interference between the support arm llb and a tool that approaches during machining. Additionally, the mechanism operation control unit 10 includes:
As shown in FIG. 1, a main shaft 12, a tool rest 13, etc. are connected to each other so as to be freely controllable.

Since the numerically controlled lathe 1 has the above configuration, during machining, the main control section 2 calls the machining program PRO from the machining program memory 7 and executes the mechanism operation control section 10.
The mechanism operation control unit 10 outputs the nib program P for the concerned
The drive of the tool post 13 and the main spindle 12 is controlled based on the RO, but as the machining progresses, if machining using the steady rest device 11 is instructed during the machining program PRO, the main control The unit 2 drives and controls the steady rest device 11 based on the machining program PRO to position the steady rest device 11 at a predetermined position.

That is, if the Z coordinate value Z1 at which the steady rest device 11 should be positioned is specified in the machining program PRO, the main control section 2 immediately moves the steady rest device 11 to a predetermined position via the steady rest control section 9. Position at Z coordinate Z1 and workpiece 1
5 is supported at that position and processing begins. In addition, since two steady rest devices 11 are provided for one lathe 1 as shown in FIG. 5, the machining program PRO
The coordinate value Z1 supported inside is the total length L of the workpiece 15.
/2 or larger than the parameter value preset in the steady rest control unit 9 (therefore, if the coordinate value Zl is located on the chuck side), the steady rest device on the chuck 17 side in FIG. 11A to the coordinate value Z1, and if not (therefore, if the coordinate value Z1 is located on the tailstock side), move the steady rest device 11B on the tailstock 19 side to the coordinate value Z1 and position it. I do. Further, the steady rest device 11 to be used may, of course, be of either a two-point support system or a three-point support system, as described above.

Next, if the coordinate value Z1 for positioning the steady rest device 11 is not specified in the machining program PRO, or if machining using the steady rest device 11 is not specifically instructed, the main control unit 2 First, the machining program P
Based on the material diameter and total length of the workpiece 15 during RO, it is determined by equation (1) whether or not the machining should be performed using the steady rest device 11 (i.e., the main control unit 2 Among the machining operations instructed during the program PRO, whether or not the steady rest device 11 should be used is determined by formula (1) for all operations other than those for which the positioning coordinate value Z1 of the steady rest device 11 is specified. ).

Shikaku aD...
......(1) (α is a parameter set in advance in the numerically controlled lathe 1) When it is determined that L<aD, '
Since the diameter of the material is sufficiently large compared to the overall length, there is no need to use the steady rest device 11 during processing, and therefore the main control unit 2 uses the steady rest device 11 during processing based on the Niprogram PRO for this purpose. Start processing immediately.

If it is determined that L>aD, the main control section 2 uses the steady rest control section 9 to effectively suppress chatter that occurs during machining by using the steady rest device 11.
Then, a command is given to position the steady rest device 11 at a predetermined position.

That is, in the automatic positioning control of the steady rest device 11 performed by the steady rest control section 9, the steady rest device 11 is
(1) Follow-up control that moves by following the movement in the axial direction, and simply positioning at least one of the two steady rest devices 11 at a predetermined position to perform machining. , (2) There are two types of control: support position optimization control.

(1) Follow-up control is performed when the machining instructed by the machining program PRO is a machining other than thread cutting or grooving, and the length of the machining area in the Z-axis direction is set in advance as a parameter in the numerically controlled lathe 1. This is a control method that is performed when the value is greater than or equal to the specified value, and provides the most accurate machining with the least chatter.

That is, when performing follow-up control, the steady rest control section 9
The workpiece flat part shape memory 6 is searched to find the current flat part of the workpiece 15, that is, a parallel bar-shaped part (for example,
In FIG. 9, the coordinate values of the parts where the anti-sway device 11 can be set are determined in the parts SA, SC, SE, etc.).

As shown in FIG. 4, the workpiece flat part shape memory 6 stores the coordinate values of the flat part 15a of the workpiece 15 to be machined, which has a width in the Z-axis direction that allows the anti-sway device 11 to be set, as the starting point and the coordinate value of the flat part 15a. The Z coordinate value of the end point 2,2 is further stored as the diameter D (corresponding to the X coordinate value) of the part,
The workpiece flat part table TABL is stored, and therefore, the steady rest control unit 9 searches the workpiece flat part table TABL in the workpiece flat part shape memory 6 to immediately control the workpiece 15 related to the workpiece 15 to be machined. It is possible to know the distribution of flat parts 15a that can be set. The contents of this workpiece flat part table TABL are rewritten as the machining by the machining program PRO progresses. The trajectory of the tool (the trajectory of the tool tip is nothing but the one that indicates the outer shape of the workpiece 15 at that point in time; therefore, by calculating the trajectory of the tool tip, it is possible to determine the existence and formation of a flat portion 15a that does not change in the X coordinate. ), the formation status of the flat part 15a of the workpiece 15 is immediately calculated by the main controller 2, and based on the result, the main controller 2 rewrites the contents of the workpiece flat part table TABL. . ], the steady rest control unit 9 can always know the latest formation status of the flat portion 15a on the claw.

(The following is a margin) Note that, as shown in FIG. If it is smaller than the sum of the Z-axis dimension ZR (see Figures 5 and 7) of the part plus the predetermined parameter value, it is assumed that the steady rest device 11 cannot follow the tool in synchronization. , "X" indicating that tracking is not possible or possible is written in the tracking possibility flag storage area FA in the workpiece flat part table TABL.
” flag FLG is set. Further, when the length Ll is larger than the sum of the Z-axis dimension ZR of the support portion of the steady rest device 11 plus a predetermined parameter value, the steady rest device 11 can follow in synchronization with the tool. As such, a flag FLG of "O" indicating that tracking is possible is set in the tracking enable/disable flag storage area FA in the workpiece flat part table TABL.

Therefore, the steady rest control section 9 drives the steadying device 11B, and the mechanism operation control section 10 drives the tool rest 13.
The workpiece 1 is passed through the tool 20 mounted on the tool post 13.
When performing machining based on the machining program PRO for 5, as shown in FIG. The workpiece 15 being machined is moved and held in the C direction at a feed rate equal to the feed rate in the Z-axis direction of 20 while being supported by support rollers lla. As a result, the steady rest device 11B is moved and driven in synchronization with the feed of the tool 20 on the almost opposite side of the tool 20 performing the machining operation, so the workpiece 15 is prevented from chattering due to the steady rest device 11B. It is supported reliably and machining is performed with high precision.

In addition, since the portions SB, SD, etc. in FIG. 9 are tapered portions, it is impossible to perform follow-up control of the steady rest device 11B facing the tool 20.
The support of the workpiece 15 by the tool 20 is temporarily suspended, and the steady rest device 1'lA on the other chuck 17 side is moved to the flat part SE of the workpiece 15 that is closest to the part SB of the workpiece 15 processed by the tool 20 within a predetermined distance or more. In section 15a, the part where the flag FLG in the followability flag storage area FA is set to "O" is moved to the position ZP closest to the machining part SH, and the workpiece 15 is supported at that position ZP. In this state, the steady rest device 11B is separated from the workpiece 15 and the tool 20 is made to process the portion SB, while the steady rest control section 9 starts positioning the steady rest device 11B with respect to the next flat portion 15a. That is, the flat portion 15a that the tool 20 processes next is the portion SC, and therefore the tool 20 processes the portion S.
When moving from machining B to SC, it is necessary to position the steady rest device 11B at a predetermined position in the portion SC.

The positioning position of this steady rest device 11B is set at the encounter point MP.
The coordinate position of the encounter point MP is determined from equation (2) as shown in FIG.

f: 11 is also constant (ν/min) F: Rapid traverse speed of steady rest device (mm 7 min) 11: Relief amount (constant) (-42: Distance between tool and steady rest device (body) lV: Encounter point Distance to (,) l: Radial difference - Clearance amount (mm) K: Follow-up delay amount of the steady rest device with respect to the tool (-゛T temporary constant (minutes) In other words, the distance #13 from the tool 20 to the encounter point MP is , and the distance 11113 allows the steady rest control unit 9 to calculate the Z coordinate value for positioning the steady rest device 11B (the current position of the tool 20 at the time of calculating the distance 43 is known). ).Thus, steady rest device 1
1B is positioned at the encounter point MP of the portion SC, the tool 20 finishes machining the portion SB and begins machining the portion SC, and then the tool 20 passes through the Z coordinate position corresponding to the encounter point MP and a predetermined delay amount. When the workpiece 15 has moved to the left in FIG. 10 by an amount corresponding to K, the steady rest device 11B is moved in the X-axis direction by an amount equivalent to the clearance amount, and the workpiece 15 is supported.
Immediately, follow-up control is started in conjunction with the feeding of the tool 20 in the Z-axis direction (in this case, in the direction of arrow C).

In addition, when calculating the distance I13, the distance fi11 between the tool and the steady rest device is the distance! The distance at the time of calculation is used. Also, the time point when the distance I11 is calculated (that is, the time point when the distance l is sampled) is when the steady rest device 11B is on the workpiece 1.
Of course, equation (2) changes depending on whether or not the steady rest device 11
The distance 13 is calculated before B leaves the portion SA, and the Z coordinate for positioning the steady rest device 11B is determined from the distance 13 at that point.

In this way, when the steady rest device 11B enters the follow-up control again, the steady rest control section 9 separates the steady rest device 11A, which had been supporting the workpiece 15, from the workpiece 15 and moves it to a predetermined standby position to standby. In addition, steady rest device 11B
In order to avoid complicated control such as calculating the encounter point MP and positioning to the encounter point MP, if the flat part 15a sandwiched between the unfollowable parts SB and SD is less than a predetermined value, , it is also possible to treat the portions SC as unfollowable portions, and to configure the portions SB, SC, and SD to be all supported by the steady rest device 11A.

Next, (
2) Regarding the support position optimization control, in this case, the steady rest control unit 9 searches for the workpiece flat part table TABL in the workpiece flat part shape memory 6, and determines the position that is closest to the machining area to be processed, and If you own two,
Find a flat part 15a near the center of the workpiece 15 that does not interfere with the movement of the tool 20 during machining, and move the steady rest device 11 to the found flat part 15a to support the workpiece 15 and start machining. Start.

At this time, the determined distance 111d to the flat portion 15a
However, as shown in FIGS. 5 and 7, when the total length of the workpiece 15 is d less than L/2, the tail stock 19
Move the side steady rest device 11B to the flat portion 15a to support the workpiece 15, and if d≧L/2,
As shown in FIGS. 6 and 8, the steady rest device 11A on the chuck 17 side is moved to the flat portion 15a, and in this state, the workpiece 15 is supported and machining is started.

As shown in FIGS. 5 and 6, when the three-point steady rest device 11 is used, a predetermined steady rest device 11A is attached to the flat portion 15a obtained under the conditions shown in (1), (2), and (3) above. Or position 11B, and then position the other steady rest device 1.
1B or IIA, when the steady rest device 11A is set on the flat portion 15a determined under the conditions shown in ■, ■, and ■, the steady rest device 11B is removed from the chuck 17 as shown in FIG. The distance is 4 degrees from aD, and the steady rest device 11 is positioned at the flat part 15a at the position closest to αD.
When B is sected to the flat part 15a obtained under the conditions shown in ■, ■, and ■, the steady rest device 11A is moved so that the distance from the tail stock 19, g is 4t, is 0, as shown in FIG.
It is also possible to configure the workpiece 15 to be supported by the two steady rest devices 11 by positioning the workpiece 15 at the flat portion 15a at the position closest to αD within 0. Note that the workpiece 15 is supported by two such steady rest devices 11.
If the total length of αD≦L(2aD−1, then (l is
This is particularly effective in improving machining accuracy when the two steady rest devices 11A and IIB are closest to each other and the distance in the Z-axis direction from each other, that is, the total length of the workpiece 15 is not that long. .

(g) 0 Effects of the Invention As described above, according to the present invention, the workpiece flat part shape memory 6 stores the workpiece flat part table TABL indicating the position of the flat part 15a during processing of the workpiece 15.
etc., and store the flat part table TABL of the work.
In addition to sequentially rewriting the contents according to the progress of processing,
During machining based on the machining program PRO, workpiece 1
It is calculated and determined whether the total length of 5 is longer than a predetermined length with respect to its diameter, etc., and as a result, if it is determined that the length is longer than a predetermined length, the The workpiece flat part table TABL is searched to determine the flat part 15a of the workpiece 15 to be machined, and the steady rest device 11 is moved and positioned to the determined flat part 15a to support the workpiece 15 being machined. As a result, even if the operator does not instruct the use of the steady rest device 11 in the machining program PRO, the numerically controlled lathe 1 automatically determines the necessity and controls the drive of the steady rest device 11. , the workpiece 15 is machined with high precision without causing chatter. Further, the steady rest device 11 is positioned at a position (not necessarily a fixed position) based on the workpiece flat table TABL, which is rewritten as the machining progresses.

As already mentioned, during follow-up control, the steady rest device 11 is driven to move in the Z-axis direction in synchronization with the movement of the tool 20, and therefore, its positioning position has a certain width in the Z-axis direction. Become. ) is determined, the steady rest device 11 is always positioned at an appropriate position, and efficient machining can be performed.

[Brief explanation of drawings]

FIG. 1 is a control block diagram showing an example of a numerically controlled lathe to which the drive control method for a steady rest device according to the present invention is applied; FIG. 2 is a side view showing an example of a three-point steady rest device;
The figure is a side view showing an example of a two-point support steady rest device, FIG. 4 is a schematic diagram showing a workpiece flat part table stored in the workpiece flat part shape memory, and FIGS. 5 to 9 are control of the steady rest device. FIG. 10 is a diagram showing the dimensional relationship when determining the encounter point between the tool and the steady rest device in follow-up control. 1 ・Numerical control lathe 6 ・Memory (workpiece flat part shape memory) 11, II
A, IIB... Steady rest device 15 Workpiece 15a - Flat part D - Diameter L - Full length PRO - Machining program T A B L... Workpiece flat part table Applicant
Yamazaki Iron Works Co., Ltd. Agent Patent Attorney Phase 1) Shinji (and 1 other person) Figure 1 U Figure 2 Figure 3 ” Figure 7

Claims (1)

[Claims] A numerically controlled lathe in which one or more steady rest devices are movably provided, is provided with a memory storing a workpiece flat part table indicating the position of the flat part during machining of the workpiece, The contents of the flat part table are sequentially rewritten as the machining progresses, and during machining based on the machining program, it is calculated and determined whether the total length of the workpiece is longer than a predetermined length with respect to the diameter of the workpiece. As a result, if it is determined that the length is longer than a predetermined length, search the workpiece flat part table in the memory, and
A drive control method for a steady rest device in a numerically controlled lathe configured to determine a flat portion of the workpiece to be machined, and move and position the steady rest device on the determined flat portion to support the workpiece being machined. .