JPS59166446A - Method of controlling speed of tool feed in numerical-controlled processing machine - Google Patents

Abstract

PURPOSE:To make an operation unmanned and shorten processing time, by detecting a difficult processing point from the processing data of an auxiliary memory to apply an instruction to start lowering the feed velocity of a tool before the completion of a speed change action. CONSTITUTION:When the action of a numerical controller 6 is instructed through a keyboard 8, processing data for measurement points 0-3 are read from an auxiliary memory 7 to calculate the distance 12 between the measurement points 2, 3. Since the region between the points 2, 3 is flat, the distance is equal to that between X-Y coordinates, so that the controller 6 selects a high feed speed. When it comes to the region between measurement points 4, 5 after sequential selected actions, a low feed speed is chosen and a numerical-controlled processing machine is instructed in accordance with the data change time before the switchover of the tool feed speed to process the region between the points 4, 5 at the low feed speed. When the processing proceeds on the flat region to a measurement point 16, the speed switchover time does not need to be taken into consideration, so that only a high-speed instruction is applied. The machine is thus run in an unattended manner at a high rate of operation.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for controlling tool feed rate in an NC processing machine.

Generally, when manufacturing molds, the shape of a master model made of plaster or synthetic resin is represented as a set of numerical data of X, Y, and Z coordinates (x, y, z) and temporarily stored in an auxiliary storage device. During machining, a workpiece is machined three-dimensionally by controlling an NC machine while sequentially reading data.

By the way, NC processing machines have a limit to the response speed of their servo systems, such as servo valves, and are unable to follow sudden changes in coordinates. Therefore, the tool feed speed must be lowered before reaching difficult-to-machine areas with large irregularities. If this is not done, there are problems such as damage to the tool and reduction in machining accuracy. For this reason, in the past, an operator accompanied the machining operation and manually lowered the feed rate just before the tool reached a location with large irregularities, or when operating unattended at night, etc. Since the system was designed to operate uniformly according to the speed of the location, there were problems such as requiring more manpower and lowering the operating rate.

In view of these problems, the present invention detects difficult-to-machine locations from machining data stored in an auxiliary storage device, and starts reducing the tool feed speed before reaching the difficult-to-machine locations, thereby allowing unmanned operation. The purpose of this study is to propose a new tool feed rate control method that aims to improve efficiency and operation rate.

Therefore, the details of the present invention will be explained below based on examples.

FIG. 1 is a flowchart showing the process of creating NC machining data using a master model, in which the operator refers to the measurement plan table and ATC table to determine the measurement order of the measurement model and the data to be used for each measurement section. The type and size of the tool, the number of rotations of the tool, and the feed rate (hereinafter referred to as cutting condition data) are instructed to the measurement program device. Based on the signal from this programming device, the ball dimensional profile measuring device moves the probe toward the center while drawing a spiral trajectory without touching the surface of the model, as shown in Figure 2 (a). , In the straight section, the distance is determined for each tool, for example, 14 mm for A tool and 20 mm for B tool.
Every time you move mm, a measurement section is selected and its X, Y, Z coordinates, that is, shape data is output, and in curved sections, a measurement section is selected for each amount of movement in the Z-axis direction, and the shape is output. Output data. As a result, Figure 2 (b)
As shown in the measurement section O to 4 and 1 in the flat section.
Measurement distance sentences from 6 to 19, ... sentence 3, sentence, b
... Sentence, 2 is long, and the measurement distance of curved surface parts 4 to 16 is # Sentence≠ ...-The bamboo is short, and shape data is collected and processed with a sampling density proportional to the degree of unevenness of the model surface. The aim is to improve accuracy. The shape data of each measurement area 0, l, 2, etc. collected in this way is attached with an identification code for each measurement area, and is stored one after another in the auxiliary storage device in pairs with the cutting condition data. . Fig. 3 schematically shows the processing data stored in the auxiliary storage device, and the processing data for each measurement area is as shown in Table 1. It is configured by arranging data and shape data in this order.

The speed data in this machining condition data represents the feed speed of the tool in each measurement area, which is set based on the ATC table when creating the measurement program.

Table 1 The present invention utilizes the above-mentioned data collection characteristics, that is, shape data is collected at a sampling density proportional to the degree of unevenness of the model, and the distance between the XY coordinates of the data indicates the processing difficulty of the measurement section. The focus is on things related to the size of .

FIG. 4 is a schematic diagram showing an example of a device used in the present invention, and reference numeral 1 in the figure is an NC processing machine main body, in which a workpiece W is moved in the X-Y axis direction by a servo motor 2.3. It consists of a workpiece mounting table 4 and a cutting device 5 disposed above the workpiece mounting table 4.

Reference numeral 6 denotes an NC control device, which is configured to control the NC processing machine 1 using processing data from an auxiliary storage device 7 and commands from a keyboard 8. Furthermore, before transferring the machining data to the NG machining machine l, the NC control device 6 reads the machining data for a certain range, for example, up to three ahead from the auxiliary storage device 7, and reads the machining data for two ahead and three ahead.
Distance of toe measurement section *9. n, that is, the measurement interval X-Y
Calculate coordinates. This measurement interval distance f11. Compare l n with the distance of the standard feedrate set for each tool shown in Table 2 and select the corresponding standard feedrate, which is smaller than the tool feedrate set in the machining data. In this case, the reference feedrate is configured to be transferred to the processing machine before the tool speed conversion time of the processing machine.

Table 2 Next, the operation of the apparatus configured as described above will be explained based on the flowchart 1 shown in FIG.

When the operation of the device is commanded from the keyboard 8, the processing data for measurement sections 0 to 3 is output from the auxiliary storage device 7 to the NC control device 6. Calculate interval distance sentence 2. Since this measurement section is flat, the distance intersection 2 is 14 mm (tool A is used), and the NC control device 6 selects a high speed, namely 1200 mm/min (Table 2), as the reference feed rate, but -
], Since the tool feed speed set in the machining data of measurement area 0 is a medium speed of 1000 mm/min (Table 1), the processing machine is commanded the speed set in the machining data,
Cutting is performed with a tool feed rate of 1000 mm/min. When the measurement section 2 is reached in this way, the NC control device 6 calculates the inter-measurement distance fL4 to be calculated in the measurement section 2, that is, the measurement The coordinate distance between sections 4 and 5 is calculated based on these shape data. These measurement sections 4 and 5 are where undulations begin to occur as shown in FIG. 2 (b), and the distance between measurements 4 is as small as 3 mm. As a result, the NC control device sets the standard feed rate to 8.
Select 00mm/min and set the machining/data feed rate to 10.
This selected standard feed rate of 800 mm/min is commanded to the processing machine before converting to 00 mm/min. This results in N
The C processing machine proceeds with cutting measurement area 2 while gradually decreasing the feed rate of the tool in order to adjust the feed rate to 800 fflIIIZ. Through the same process, measurement area 3.4 is also cut by lowering the feed rate. When measurement area 5 is reached in this way, the feed rate of the tool has been reduced to a speed at which the servo valve of the tool etc. can sufficiently follow the curved surface machining that is about to begin, that is, 800 mm/min.

Due to this low-speed feeding, measurement areas 5 to 16, which are difficult to machine,
The processing up to this point is performed with high precision. When the machining moves to the measurement zone 16 where the machining is smooth, the reference feed rate is switched to high-speed feed, so the machining proceeds at the feed rate set in the machining data.

In other words, the feed speed is increased from the low speed of 800 mm/min, which occurs when machining a curved surface part to the flat part, to a medium speed of 1000 mm/min.
Even if changes in the tool feed rate to mm/min are not particularly taken into consideration, changes in workability and damage to the tool due to follow-up delays of servo valves, etc. do not occur.

As explained above, according to the present invention, the distance between the read coordinate points in the shape measurement data of the model is constant from the current machining point based on the fact that it is long in a flat cylindrical place and short in a place with large undulations. The distance between the read coordinate points to the measurement points that are several pieces apart is detected in advance from the machining data, and when this distance is short, the tool feed speed is lowered in advance. The feed speed can be automatically reduced to the tool feed speed that can follow the machining shape, allowing unmanned operation with a high operating rate.

[Brief explanation of drawings]

Figure 1 is a flowchart showing the method of creating an NC tape using a master model, Figures 2 (a) and (b) are explanatory diagrams showing the operation of the three-dimensional profile measuring device, and Figure 3 is
A schematic diagram showing the data arrangement of the NC tape, FIG. 4 is a block diagram showing an example of the apparatus used in the present invention, and FIG.
It is a flowchart which shows the operation|movement of the same device as the above. 1...NC processing ja 6...NC control device 7...Auxiliary storage device Fig. 2 (b) Fig. 3 Procedures Amendment (Torido) May 18, 1988 1 , Indication of the case Patent Application No. 19235 of 1982 2 Title of the invention Method for controlling tool feed speed in an NC processing machine 3 Person making the amendment Relationship to the case Applicant 6-27-8 Jingumae, Shibuya-ku, Tokyo (532) Honda Motor Co., Ltd. Representative Yoshiyoshi Kawashima 4, Agent 112 7a0
3(815) 13100 2-1-2 Koishikawa, Bunkyo-ku, Tokyo: □゛: 11 Sankyo Building j”+’: ito1-
J (and 1 other person) 5. Subject of amendment: Description and drawings of the description and drawings. 6. Contents of amendment: As attached (blind). Feed rate control method 2, Claims Converting to three-dimensional data at a sampling density corresponding to the size of shape change of the reference model, and assisting machining data by pairing the three-dimensional data and cutting condition data. The processing data is stored in a storage means and is read out sequentially while being NC.
In a method for controlling a processing machine, the processing data is set to N
Before transferring to the C processing machine, calculate the distance between the measurement coordinates of a certain number of consecutive measurement points, and compare this distance with the distance of the reference feed rate of the tool of the NC processing machine to determine the distance of the reference feed rate. When the feed rate changes small, the reference feed rate is changed to N according to the machining data transfer before the tool speed switching time that the NC processing machine has.
A method for controlling a tool feed rate in an NC processing machine, comprising instructing a C processing machine to move the tool at the reference feed rate. 3. Detailed Description of the Invention The present invention relates to a method of controlling tool feed rate in an NC processing machine. Generally, when manufacturing molds, the shape of a master model made of plaster or synthetic resin is expressed as a set of numerical data of x, y, z coordinates (X, y, z) and temporarily stored in an auxiliary storage device. During machining, a workpiece is machined three-dimensionally by controlling an NC machine while sequentially reading data. By the way, NC processing machines have a limit to the response speed of their servo systems, such as servo motors, and cannot follow sudden changes in coordinates. Therefore, the tool feed speed must be reduced before reaching a difficult-to-process location with large irregularities. If this is not done, there are problems such as damage to the tool and reduction in machining accuracy. For this reason, in the past, an operator accompanied the machining operation and manually lowered the feed rate just before the tool reached a location with large irregularities, or when operating unattended at night, etc. Since the work was done uniformly according to the speed of the location, there were problems such as requiring manpower and requiring a long time to pressurize. In view of such problems, the present invention detects difficult-to-machine locations from machining data stored in an auxiliary storage device, thereby reducing data on the difficult-to-machine locations and reducing the time required to change the speed of a servo motor, etc. The purpose of this study is to propose a new tool feed rate control method that instructs the tool to start reducing the feed rate before the speed change is completed, thereby achieving unmanned machining and shortening machining time. do. Therefore, the details of the present invention will be explained below based on examples. FIG. 1 is a flowchart showing the process of creating NC machining data using a reference model, and the operator:
Refer to the measurement plan table and ATC table to inform the measurement program device of the measurement order of the measurement model, the type and size of the tool to be used at each measurement point, and the rotation speed and feed rate of the tool (hereinafter referred to as cutting condition data). command. The coordinate measuring machine operates as shown in Fig. 2 (
As shown in (a), the probe is not brought into contact with the surface of the model, but is moved toward the center while drawing a spiral trajectory, and in the flat part, it is moved at a distance determined for each tool, such as tool A. For tool B, a measurement point is determined every time the tool moves 14 mm, and for tool B, it is determined every 20 mm, and the machining data of the x, Y, and Z coordinates is output. Decide and output the machining data. As a result, as shown in FIG. 2(b), the distances of the measurement points O to 4 and 16 to 19 on the flat section can be seen. ...! 13. Sentence, t... Sentence, t is long, and the measurement pressure ml a of curved surface portions 4 to 16 is...
Ls is shortened to collect machining data at a density proportional to the degree of unevenness on the model surface, thereby improving machining accuracy. Figure 3 schematically shows the data of the machining areas stored in the auxiliary storage device.The data of each machining area includes the identification code of the machining area, machining condition data, and machining data group as shown in Table 1. It is organized in the following order. The feed rate data in this machining condition data is programmed to be selected and set from the ATC table when creating the measurement program. The present invention utilizes the above-mentioned data collection characteristic, that is, processing data is collected at a density proportional to the degree of unevenness of the model, and the distance between the XY coordinates between the processing data is related to the degree of processing difficulty. The focus is on doing things. FIG. 4 is a schematic diagram showing an example of a device used in the present invention, and reference numeral 1 in the figure is an NC processing machine main body, in which a workpiece W is moved in the X-Y axis direction by a servo motor 2.3. It consists of a workpiece mounting table 4 and a cutting device 5 disposed above the workpiece mounting table 4. Reference numeral 6 denotes an NC control device, which is configured to control the NC processing machine 1 based on processing data from the auxiliary storage device 7 and commands from the keyboard 8. Furthermore, this N
The C control device 6 performs NC processing I! Before transferring the machining data to the auxiliary storage device 7, the machining data for a certain range, for example, up to three points ahead, is read from the auxiliary storage device 7, and the distance In between the second and third measuring points, that is, the measuring point Calculate the X-Y coordinates between. This distance between measurement points fLn is compared with the distance of the standard feed rate set for each tool shown in Table 2, and the corresponding standard feed rate is selected, and this distance is smaller than the distance currently being machined. In some cases, the selected feed rate is commanded to the processing machine before the time required to switch the tool speed of the processing machine, that is, before the switching is completed. Table 2 Next, the operation of the apparatus configured as described above will be explained based on the flowchart shown in FIG. When the operation of the device is commanded from the keyboard 8, the processing data for measurement points O to 3 is read from the auxiliary storage device 7, and the inter-measurement point distance statement 2 between measurement points 2 and 3 is calculated. Since the measurement points are flat, the distance statement 2 is 14 mm, which matches the distance between the XY coordinates, and the NC control device 6 selects a high speed, that is, 1200 mmZ. When the measurement points 4 and 5 are reached by sequential selection in this way, the feed rate is
800mmZ will be selected, and a command will be given to the NC machine at the time of data conversion before the tool feedrate is changed, so that the machining feedrate between these measurements will be 800 m+n/
Process in minutes. Further, when moving to the measurement point 16 where the machining is easy in this manner, there is no need to consider the speed switching time, so it is only necessary to issue a high speed command. In other words, there is no change in workability or damage to the tool due to a follow-up delay of the servo motor or the like that occurs when machining a curved surface part to a flat part. As explained above, according to the present invention, based on the fact that the distance between the read coordinate points in the shape measurement data of the model is long in flat places and short in places with large undulations, The distance between the read coordinate points to the distant measurement point was detected in advance from the machining data, and when this distance was short, the tool feed speed was lowered in advance. The speed can be automatically reduced to a tool feed rate that can follow the machining shape, allowing unmanned operation with a high operating rate. 4. Brief explanation of the drawings Figure 1 is a flowchart showing the method of creating an NC tape using a reference model, Figures 2 (a) and (b) are explanatory diagrams showing the operation of the three-dimensional measuring device, respectively. FIG. 3 is a schematic diagram showing the data arrangement of the NC tape, FIG. 4 is a block diagram showing an example of the apparatus used in the present invention, and FIG. 5 is a flowchart showing the operation of the same apparatus. ■・・・NC processing machine 6・・・NC control device 7
...Auxiliary storage device applicant Honda Motor Co., Ltd. agent Patent attorney Haruto Nishikawa Katsuhiko Kimura

Claims (1)

[Claims] The reference model is converted into three-dimensional data while selecting measurement areas with a sampling density corresponding to the size of the shape change, and processing data, which is a pair of the three-dimensional data and cutting condition data, is stored in an auxiliary storage means. However, in the method of controlling the NC processing machine while sequentially reading out the processing data,
Before transferring the machining data to the NC processing machine, the distance between the measurement coordinates of a certain number of consecutive measurement sections is determined, and the distance is compared with the distance of the standard feed rate of the tool of the NC processing machine to calculate the distance. Find the feed rate corresponding to the distance of the standard feed rate,
When the feed rate is smaller than the feed rate set by the machining data, the reference feed rate is commanded to the NC machine before the tool speed conversion time of the NC machine, and the tool is moved at the reference feed rate. NC characterized by
A method of controlling the tool feed rate in a processing machine.