JPH0430910A - Numerically controlled device provided with synchronous tapping function - Google Patents

Abstract

PURPOSE:To prevent a tap from breaking for eliminating waste of raw material and taps by automatically selecting the load allowable value to the tap, monitoring the overload during synchronous tapping, stopping, if over loaded and returning the tap to the start point of tapping. CONSTITUTION:A synchronous tapping command arithmetic and control section 2 sends the commands, which are sent from a part program reading-in.analysis section 1, if it has a tap size discrimination command, to a allowable value selection section 9, and selects a load allowable value from an allowable value storing section 8 and transfers it to a main spindle load monitoring section 10. A synchronous operation control section 3 controls synchronous tapping, and the main spindle load monitoring section 10 reads main spindle loads from a main load detecting section 7 and monitors whether or not the main spindle is over loaded. When it is judged to be not over loaded, synchronous tapping controlling and the monitoring of the load to the main spindle are continued, and when it is overloaded, a signal is sent to an alarm generating section 11 to generate an alarm and send an overload signal to a main spindle returning control section 12. The main spindle returning control section 12 sends a synchronous returning command to the synchronous operation control section 3 to control the revolution of the main spindle and the stopping and returning of a feed shaft.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a numerical control device having a synchronous tapping function that performs tapping by synchronizing the rotation of a main shaft and a feed shaft.

(Prior Art) FIG. 6 is a block diagram showing an example of a conventional numerical control device having a synchronous tapping function.

First, a part program created by a programmer is read into the part program reading/analyzing section 1 and analyzed, and a synchronous tapping command SST is sent to the synchronous tapping command calculating section 2. The synchronous tapping command SST is read into the synchronous tapping command calculation section 2 and calculated, and the synchronous operation control command SSC is calculated and sent to the synchronous operation control section 3. The synchronous operation control command SSC is read into the synchronous operation control unit 3, and converted into a spindle drive command SMD and a feed axis drive command SFD for synchronizing the rotation of the spindle and the feed axis. The data are sent to section 4, respectively. The main shaft driving section 5 controls the driving of the main shaft according to the main shaft driving command SMD, and the feed shaft driving section 4 controls the driving of the feeding shaft according to the feeding shaft driving command SFD.

FIG. 7 schematically illustrates the operation of general synchronous tapping.

First, position the tapper at the tapping position at the level of the tapping start point (point R) (1), synchronize the rotation of the spindle with the feed axis, and feed it to the level of the tapping end point (point 2) (2). If there is a dwell command at the 2-point level, follow that command to keep the tapper at the 2-point level (3), reverse and synchronize the rotation of the main shaft and the feed axis to return the tapper to the 8-point level 4), and then The operation of positioning the tapper at the tap position (5) is performed.

(Problem to be solved by the invention) When tapping is performed using a conventional numerical control device equipped with a synchronous tapping function, the load applied to the tapper increases due to friction between the tapper and chips during cutting. The breakage load of the tapper was exceeded and the tapper sometimes broke.

The present invention was made in view of the above-mentioned circumstances, and
An object of the present invention is to provide a numerical control device with a synchronous tapping function that can prevent breakage of the tapper.

(Means for Solving the Problems) The present invention relates to a numerical control device having a synchronous tapping function that performs tapping by synchronizing the rotation of a main spindle and a feed axis. a detection means for detecting a load applied to the spindle; a storage means for preliminarily storing at least one allowable load value according to a tap size; and a spindle load detected by the detection means is selected from the storage means. monitoring means for monitoring whether an overload has occurred exceeding a load tolerance corresponding to the tap size currently in use; and when the monitoring means determines that there is an overload, the rotation of the main shaft and the feed shaft are stopped; This is achieved by providing a control means for synchronizing the reversal and returning to the tapping starting point.

According to the present invention, even if the load applied to the tapper increases during tapping and exceeds the allowable load value of the tapper, the overload is immediately detected and the cutting of the tapper is stopped. Since the tapper can be returned to the tapping starting point, breakage of the tapper can be prevented.

(Embodiment) FIG. 1 is a block diagram showing an example of a numerical control device having a synchronous tapping function of the present invention in correspondence with FIG. 6, and the same components are given the same reference numerals.

First, the part program created by the programmer is read and analyzed by the part program reading/analysis section 1, and the synchronous tapping command SST' is sent to the synchronous tapping command calculation section 2.
sent to. The synchronous tapping command 557' is read into the synchronous tapping command calculation section 2 and calculated, and the synchronous operation control command SSC and tap size identification command STS are calculated and sent to the synchronous operation control section 3 and the tolerance selection section 9, respectively. Ru.

The synchronous operation control command SSC is read into the synchronous operation control unit 3, and converted into a spindle drive command SMD and a feed axis drive command SFD for synchronizing the rotation of the spindle and the feed axis. The data are sent to section 4, respectively. Then, the spindle drive unit 5 controls the drive of the spindle motor 6 according to the spindle drive command SMD, and the feed axis drive unit 4 controls the feed axis according to the feed axis drive command SFD. and,
A spindle load detector 7 connected to the spindle motor 6 detects the load SML applied to the spindle and sends it to the spindle load monitor 10 . On the other hand, the load tolerance according to the tap size is stored in advance in the tolerance storage unit 8, and when the tap size identification command STS is read into the tolerance selection unit 9, the load tolerance according to the tap size identification command STS is Allowable load value SL
T is selected from the allowable value storage unit 8 and sent to the spindle load pressure detection unit 0. Then, the spindle load SML and the load tolerance SLT sent from the spindle load pressure detection unit 7 and the allowable value selection unit 9 to the spindle load monitoring unit IO are compared to monitor whether or not an overload has occurred. If it is determined that this is the case, an alarm generation signal SAG is sent to the alarm generation section 11, and at the same time, an overload signal SQL is sent to the spindle return control section 12. Then, a synchronization return command 55B is sent from the spindle return control unit 12 to the synchronization operation control unit 3, and a synchronization return control is performed to stop the rotation of the spindle and the feed axis, synchronize the reversal, and return to the tapping starting point. It has become.

In the above configuration, an example of its operation will be explained along the flowchart of FIG. 2.

First, the part program reading analysis unit 1 reads and analyzes the part program (step 51), and checks whether a synchronous tapping command exists (step S2).
, if a synchronous tapping command exists, the synchronous tapping command is sent to the synchronous tapping command calculation unit 2, and if there is no synchronous tapping command, all processing ends.

Here, FIG. 3 shows an example of one step of the synchronous tapping command, and each symbol represents the command shown below.

0284: Synchronous tapping command G code X, Y: Tap position command Z: Tap bottom command R: R point position command E: Spindle angle command at R point F: Tapper screw pitch amount S: Spindle rotation speed TM: Tap size identification The command synchronous tapping command calculation unit 2 checks whether or not there is a tap size identification command in the synchronous tapping command sent from the part program reading/analysis unit 1 (step S3).
), if there is a tap size identification command, the command is sent to the tolerance selection unit 9, and if there is no tap size identification command, a default command is sent to the tolerance selection unit 9. In the case of a tap size identification command, the permissible value selection unit 9 selects a load permissible value based on the command from the permissible value storage unit 8 and sends it to the spindle load monitoring unit IO (step S4), and in the case of a default command, the permissible load value is selected from the permissible value storage unit 8 and sends it to the spindle load monitoring unit 10 (Step S4). The preset value is then read out from the allowable value storage section 8 and sent to the spindle load monitoring section 10 as the allowable load value (step 55). Here, the allowable load value can be set and changed for each tap size on the screen as shown in Figure 4, and roughly speaking, in this example, even if the detected spindle load exceeds the allowable load value, it will not be considered an overload. It is also possible to set a permissible amount of time for which the data will not be used.

On the other hand, the synchronous operation control section 3 controls synchronous tapping in accordance with the synchronous operation control command (step S6), and the spindle load monitoring section 10 detects the spindle load from the spindle load detection section (step 57). The load tolerance value sent from the tolerance value selection section 9 is compared (step S8), and it is monitored whether an overload has occurred (step S9). However, such main shaft load monitoring operation is performed only for a predetermined period of time, and the reason for this will be explained below. Figure 5 is a graph showing the relationship between spindle rotation speed and spindle load during one cycle of tapping operation, where ■ to ■ are the cutting process, ■
is the return process. During this one cycle, in the steps of ■, ■, and ■, an excessive load is applied due to the inertia of the spindle, but an overload is not applied to the tapper, so there is no need to monitor the spindle load, and there is no need to monitor the spindle load. It is only necessary to monitor the spindle load in the process. To do this, for example, do not monitor the spindle load (do not move the process from step s6 to step s7) until the spindle rotation speed exceeds 90% of the command value, and do not monitor the spindle load until the spindle rotation speed exceeds 90% of the command value. When the deceleration starts, it is sufficient to start monitoring the spindle load (the process moves from step S6 to step S7), and to finish monitoring the spindle load when the deceleration starts (the process does not move from step S6 to step S7). .

The spindle load monitoring unit IO continues to control synchronous tapping and monitor the spindle load if it is determined that there is no overload (steps 56 to s8), and sends an alarm signal when it determines that an overload has occurred. It is sent to the generation unit 11 to generate an alarm (step 510),
An overload signal is sent to the spindle return control section 12. and,
The spindle return control unit 12 sends the synchronous return command to the synchronous operation control unit 3.
, the synchronous operation control unit 3 controls the rotation of the main shaft and the stop and return of the feed shaft (step 511).
, completes the IA filling of all 1.

(Effects of the Invention) As described above, according to the numerical control device equipped with the synchronous tapping function of the present invention, the allowable value suitable for the tapper is automatically selected, and during synchronous tapping (overload monitoring is performed). ,
In the event of an overload, the tapping machine is stopped and the tapper is returned to the tapping starting point, which prevents breakage of the tapper and damage to the tap hole due to breakage of the tapper, thereby reducing wastage of prime material and tapper. It is possible to eliminate this problem and improve processing efficiency.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing an example of a numerical control device equipped with a synchronous tapping function of the present invention, Fig. 2 is a flowchart showing an example of its operation, and Fig. 3 is an example of a setting screen for the allowable load value in the device of the present invention. Figure 4 is a diagram showing an example of one step of synchronous tapping command in the device of the present invention; FIG. 6 is a block diagram showing an example of a conventional numerical control device with a synchronous tapping function, and FIG. 7 is a diagram showing a general operation of general synchronous tapping. DESCRIPTION OF SYMBOLS 1... Part program reading/analysis section, 2... Synchronous tapping command calculation section, 3... Synchronous operation control section, 4.
・-Feed axis drive section, 5... Main shaft drive section, 6... Main shaft motor, 7... Main shaft load detection section, 8... Allowable value storage section, 9... Allowable value selection section, lO ... Spindle load monitoring section 11... Alarm generation section, 12... Spindle return control section.

Claims (1)

[Claims] 1. In a numerical control device equipped with a synchronous tapping function that performs tapping by synchronizing the rotation of the main spindle and the feed axis,
a detection means for detecting a load applied to the spindle during tapping; a storage means for storing in advance at least one allowable load value according to the tap size; and a spindle load detected by the detection means is selected from the storage means. monitoring means for monitoring whether an overload has occurred exceeding a load tolerance corresponding to the tap size currently in use, and stopping the rotation of the main shaft and the feed shaft when the monitoring means determines that there is an overload. A numerical control device equipped with a synchronous tapping function, characterized in that it is equipped with a control means for inverting and synchronizing and returning to the tapping starting point.