JPH0366090B2 - - Google Patents

Description

[Detailed Description of the Invention] (a) Technical Field of the Invention The present invention relates to processing control of a drill cycle suitable for application when performing a drill cycle based on an automatic program in a numerically controlled machine tool such as a numerically controlled lathe or a machining center. Regarding the method.

(c) Prior art and problems In recent numerically controlled machine tools, a series of related machining is treated as one fixed cycle, and a machining program can be created by simply inputting the fixed cycle from a keyboard etc. A so-called automatic program that can do this has been developed and put into practical use.

Although these automatic programs have made it possible for operators to create and input machining programs while referring to production drawings, there are still many points that need to be improved in these automatic programs.

(c) Prior Art and Problems Figure 3 is a schematic diagram showing the drill feed situation in a conventional drill cycle.

Conventionally, in this type of numerically controlled machine tool, when drilling is performed by an automatic program, the feed rate of the tool during machining, that is, the drill, varies from the machining start point STP to the machining end point, as shown in Figure 3.
It was set constant up to ENP. However, the load on the drill increases when the drill 16 contacts the workpiece 15 and when the drill 16 penetrates the workpiece 15, and is relatively small during intermediate cutting. A lot of stress is placed on the drill at the beginning and end of the process.
In the middle, there is no such burden. Therefore, if the feed rate of the drill is determined according to the drill load at the beginning and end of machining, the feed rate will be too slow when the middle part of the workpiece is being machined, resulting in the inconvenience of lengthening the overall machining time. If the feed rate of the drill was determined according to the load of intermediate cutting, the feed speed at the beginning and end of machining would be too fast, resulting in a shortened tool life. In this case,
Using manual programs using EIA/ISO codes, etc., compared to changing the feed during machining according to the load of the drill, increases machining time or shortens tool life, and the same program requires a large number of This is a fatal defect when attempting to process a workpiece.

(d) Purpose of the Invention In order to solve the above-mentioned drawbacks, the present invention is capable of controlling the feed rate as finely as a manual program such as EIA/ISO code when drilling using an automatic program, and when starting processing and drilling. There is no excessive load on the drill when penetrating the workpiece, and the middle part of the workpiece can be machined more quickly, contributing to longer tool life and shorter machining time. The purpose of this invention is to provide a method for controlling drilling cycles in a controlled machine tool.

(e) Structure of the Invention That is, the present invention stores the machining start point, machining end point, coordinate positions of the front and back surfaces, and standard feed rate of the workpiece to be drilled in the machining program, and also stores the machining start point, machining end point, coordinate positions of the front and back surfaces, and standard feed rate of the workpiece to be drilled in the memory. , the initial penetration distance indicating how far the drill should penetrate from the workpiece surface, the final distance from the position just before the drill reaches the backside of the workpiece to the backside of the workpiece, and the correction coefficient for the standard feed rate mentioned above. During machining, the initial plunge distance and final distance in the memory are read out, first and second points corresponding to the initial plunge distance and final distance are set on the workpiece, and the distance between the machining start point and the machining end point is set. The section up to
The first section from the processing start point to the first point, the first
It is divided into a second section from the point to the second point and a third section from the second point to the machining end point, and the cutting feed rate of the drill in each section is set as follows:
The feed rate of the drill is determined by correcting the standard feed rate instructed in the machining program based on each correction coefficient stored in the memory.
The first section and the third section are controlled to be slower than the second section.

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

FIG. 1 is a control block diagram showing an example of a numerically controlled machine tool to which the present invention is applied, and FIG. 2 is a diagram showing an embodiment of the drilling cycle machining control method according to the present invention.

The numerically controlled machine tool 1, as shown in FIG.
The main control unit 2 includes a program memory 3 in which a machining program is stored, a feed axis control unit 5, a main axis control unit 6, a feed rate calculation unit 7,
A coordinate value calculation unit 9, a parameter memory 10, and a data input device 11 such as a keyboard are connected. A feed shaft drive motor 12 is rotatably connected to the feed shaft control section 5, and a main shaft drive motor 13 for rotationally driving the main shaft is connected to the main shaft control section 6.

Since the numerically controlled machine tool 1 has the above configuration, when performing a drill cycle with the numerically controlled machine tool 1, the operator inputs the machining starting point of the workpiece 15 to be machined from the data input device 11.
Coordinate positions of STP and machining end point ENP, standard feed rate F, spindle rotation speed S, surface 15a of workpiece 15
and the coordinate position of the back surface 15b are input as processing information INF. At this time, the standard feed rate F input by the operator is equal to the cutting feed rate F2 when cutting a second section K2, which will be described later, which is the middle part of the workpiece 15. The machining information INF thus input is stored in the program memory 3 as a machining program PRO.

Note that during machining, the main control unit 2 reads the machining program PRO in the program memory 3,
Based on the machining information INF in the machining program PRO, the spindle control unit 6 is instructed so that the rotation speed of the spindle driven by the spindle drive motor 13 becomes the rotation speed S specified in the machining program PRO. Then, the feed axis control unit 5 is further driven to position the tool, that is, the drill 16, from the machine origin MZP to the machining start point STP by the feed axis drive motor 12.
In this state, the main control unit 2 applies a predetermined feed to the drill via the feed axis control unit 5 and starts drilling with the drill 16. However, prior to starting machining, the main control unit 2 16 is the processing start point
A first section K1 is set from STP to a point where a center hole is formed in the workpiece 15. That is, the main controller 2 controls the drill 16 from the parameter memory 10 to determine how far the workpiece surface 1 is in FIG.
5a, the initial plunge distance L1 indicating whether to plunge to the left in the figure is read out, and the coordinate value calculation unit calculates the coordinates of a point that has entered the left side in the figure by a distance corresponding to the initial plunge distance L1 from the workpiece surface 15a. 9, the point PT1 is set by calculating the first section K.
1, the section from the machining start point STP to the point PT1 via the workpiece 15 surface 15a is set. stored inside).

Furthermore, the main control unit 2 indicates the position where the drill 16 penetrates the workpiece 15, that is, the cutting edge of the drill 16 is located on the back surface 15.
A second section K2 and drill 1 in which the position immediately before reaching point b is calculated and determined, and the drill 16 performs a normal intermediate cutting operation based on the determined position.
A third section K3, which is the section where 6 passes through the workpiece 15, is determined. That is, the main control unit 2 reads the final distance L2 from the position immediately before the drill 16 reaches the workpiece back surface 15b to the workpiece back surface 15b from the parameter memory 10, and moves the distance L2 from the workpiece back surface 15b to the workpiece back surface 15b by a distance corresponding to the final distance L2 in the figure. The coordinate value calculation unit 9 calculates the coordinates of the point entered on the left side, and the point is calculated.
PT2 is set, and the section from point PT1 to point PT2 is set as the second section K2. Also, point PT2
to the machining end point ENP is set as the third section K3. (The coordinates of the back surface 15b of the workpiece are
Machining program in machining program memory 3
It is stored in the memory 3 as processing information INF that constitutes PRO. ) In this way, the first, second and third sections K1, K2, K
3 is set, the main control unit 2 sets the drill 1.
Apply feed to 6 and move to the machining start point STP shown in Figure 2.
Processing for the section K1 from to point PT1 is started. At this time, the feed axis control unit 5 sends the drill 16 at a cutting feed rate F1 that is slower than the standard feed rate F specified in the machining program PRO.

That is, the main controller 2 controls the drill 1 in the feed axis controller 5.
When instructing the feed speed of 6, the correction coefficient P1 corresponding to the first section K1 is extracted from the parameter memory 10.
is read out, and the feed rate calculation section 7 multiplies the standard feed rate F read out from the program memory 3 by the correction coefficient P1 (0<P≦1) to obtain the cutting feed rate F1. Based on the cutting feed rate F1, the feed axis control unit 5 is instructed to give the drill 16 a feed corresponding to the cutting feed rate F1. As a result, the drill 16 moves to the workpiece 15.
The feed of the drill 16 when the load on the drill 16 increases due to contact with is slower than the standard feed rate F specified in the processing program PRO,
There is no need to place an unreasonable burden on the drill 16.

Next, when cutting the second section K2, the feed axis control unit 5 controls the drill 16 using the machining program.
Send at a cutting feed rate F2 equal to the standard feed rate F specified in PRO. Since the load applied to the drill 16 in the section K2 is lighter than that in the section K1, the drill 16 is fed at a feed rate F2 faster than that in the section K1 to quickly process the section K2. In addition, when determining the cutting feed rate F2 of the drill 16 in the section K2, the main control section 2 reads out a predetermined correction coefficient P2 corresponding to the section K2 from the parameter memory 10, and sends the correction coefficient to the feed rate calculation section 7. A calculation is performed to multiply P2 by the standard feed rate F specified in the machining program PRO, but in this case, the correction coefficient P2 is '
Since the cutting feed rate F2 is set to 1', the corrected cutting feed rate F2 becomes equal to the standard feed rate F specified in the machining program PRO.

In this way, the section K2 is cut at the cutting feed rate F2, and when the tip of the drill 16 reaches the point PT2 and the machining of the section K2 is completed, the machining of the third section K3 is started, and the feed axis controller 5 sets the feed rate of the drill 16 to a cutting feed rate F3 that is slower than the standard feed rate F specified in the machining program PRO.
Send by.

That is, the main controller 2 controls the drill 1 in the feed axis controller 5.
6, the correction coefficient P3 corresponding to the third section K3 is input from the parameter memory 10.
is read out, and the feed rate calculation section 7 is made to calculate the cutting feed rate F3 by multiplying the standard feed rate F read out from the program memory 3 by the correction coefficient P3 (0<P3≦1), and calculates the cutting feed rate F3. Based on the cutting feed rate F3, the feed axis control section 5 is instructed to give the drill 16 a feed corresponding to the cutting feed rate F3. This causes the drill 16 to move to the workpiece 1.
5 and the load on the drill 16 increases, the feed of the drill 16 is changed to the second position where the load is lighter.
The cutting feed rate is slower than the cutting feed rate F2 in the section K2,
Therefore, no undue burden is placed on the drill 16.

In this way, the drill 16 penetrates the workpiece 15,
When the tip reaches the machining end point ENP, the feed axis control unit 5 moves the drill 16 backward in the direction of arrow B in Figure 2, and returns the tip of the drill 16 to the machining start point.
Return to STP (indicated by the dashed arrow in the figure) and complete the series of drill cycles.

Note that the standard feed rate F specified in the machining program PRO does not necessarily correspond to the cutting feed rate F2 in machining of the second section K2, and for example, the standard feed rate F1 specified in the first section K2.
is specified in the machining program PRO, and the correction coefficient P1 in the parameter memory 10 (in this case, P1=
It is also possible to obtain the cutting feed rates F2 and F3 in each section K2 and K3 using 1), P2, and P3. Therefore, in extreme cases, the standard feed rate F specified in the machining program PRO does not need to correspond to any of the cutting feed rates in each section.

(g) Effect of the invention As explained above, according to the present invention, the workpiece 1 to be drilled during the machining program PRO
5 machining start point STP, machining end point ENP, surface 1
Coordinate positions of 5a and back surface 15b, standard feed rate F
etc., as well as the parameter memory 10.
Initial penetration distance L indicating how far the drill 16 should penetrate from the workpiece surface 15a is stored in the memory such as
1. Final distance L from the position just before the drill 16 reaches the workpiece back surface 15b to the workpiece back surface 15b
2. Furthermore, the correction coefficient P for the standard feed rate
1, P2, and P3, and when machining with the drill 16, the initial plunge distance L in the memory is stored.
1. Read the final distance L2, set points PT1 and PT2 corresponding to the initial plunge distance L1 and final distance L2 for the workpiece 15, and set the machining start point STP.
The section from to the machining end point ENP is the machining start point
First section K1 from STP to point PT1, point PT
The cutting feed speeds F1, F2, and F3 of the drill 16 in each section are set in the memory. The feed rate of the drill 16 is determined by correcting the standard feed rate instructed in the machining program PRO based on each stored correction coefficient P1, P2, P3, and the feed rate of the drill 16 is determined in the first section K1 and the third section. Since K3 is controlled and configured to be slower than the second section K2, the drill 16 is fed at a slow cutting feed rate at the start of cutting and when penetrating the workpiece, when the load is large, and the load is light. During intermediate cutting, the cutting feed rate is high, so machining using a drill cycle based on an automatic program, which only had a constant feed rate from the beginning to the end of machining, has a texture similar to that of manual programs such as EIA/ISO codes. Fine control of the feed rate is now possible, which not only eliminates excessive stress on the drill when starting and penetrating the drill when drilling using an automatic program, but also allows for faster machining of the middle part of the workpiece. This makes it possible to contribute to extending tool life and shortening machining time.

[Brief explanation of drawings]

Fig. 1 is a control block diagram showing an example of a numerically controlled machine tool to which the present invention is applied, Fig. 2 is a diagram showing an embodiment of the drilling cycle machining control method according to the present invention, and Fig. 3 is a diagram showing a conventional drill. It is a schematic diagram showing the feed situation of the drill in a cycle. 1... Numerical control machine tool, 15... Work, 1
5a...Front surface, 15b...Back surface, 16...Drill, L1...Initial entry distance, L2...Final distance,
P1, P2, P3... Correction coefficient, K1... First section, K2... Second section, K3... Third section, F1, F2, F3... Cutting feed rate, PT1
...First point, PT2...Second point, PRO...Machining program, STP...Machining start point, ENP...
Processing end point.

Claims (1)

[Claims] 1. In a numerically controlled machine tool in which a drill is drive-controlled based on a machining program, during the machining program, the machining start point of the workpiece to be drilled, the machining end point, the coordinate positions of the front and back surfaces, and the standard feed rate. In addition to storing, in the memory, the initial plunge distance indicating how far the drill should penetrate from the workpiece surface, the final distance from the position just before the drill reaches the backside of the workpiece to the backside of the workpiece, and the correction for the standard feed rate. The coefficients are stored, and when machining with a drill, the initial plunge distance and final distance in the memory are read out, and first and second points corresponding to the initial plunge distance and final distance are set on the workpiece. Then, the section from the machining start point to the machining end point is defined as the first section from the machining start point to the first point, the second section from the first point to the second point, and the second section from the second point. 3rd point up to the end of machining
At the same time, the cutting feedrate of the drill in each section is determined by correcting the standard feedrate instructed in the machining program based on each correction coefficient stored in the memory. A drilling cycle machining control method in a numerically controlled machine tool, wherein the feed rate is controlled to be slower in a first section and a third section than in a second section.