JPS6085852A - Device for compensating position of shear point of tool in numerical control machine tool - Google Patents

Abstract

PURPOSE:To make it possible to automatically compensate the length of the front end part of a cutting tool to aim at facilitating the preparation of instruction programs, by providing means for compensating the instruction value of tool-feed with the use of the length of the front end part of the tool which is stored in a memory in accordance with the tool number thereof. CONSTITUTION:A control circuit 30 receives tape instructions TP which is therefore decoded, and sets a moving instruction value in the drilling direction of a tool once onto a register 34, but if a tool number is instructed by the instructions TP, the control circuit devlivers the compensating data of tool length and the data of front end part length of the tool, which are stored in an address area in a memory 33 corresponding to the tool number to an adder 35. Therefore, the adder 35 addes both compensating data together to obtain the compensating data of position of the shear point of the tool. Further, a shear point compensating circuit 36 compesates an instruction value which is set in accordance with the compensating data, and sets the thus compensated value onto a register 34. In accordance with the content set on register, distributing pulses DP are fed to a Z-axis motor control circuit. Thus, even if tools having different front lengths of their front end parts are used, the instruction values by programs may be always made equal to the effective depths, thereby it is possible to facilitate the preparation of programs.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field of the Invention The present invention relates to a tool cutting edge position correction device for a numerically controlled machine tool.

Conventional technology and problems If we take a drill as an example, the length of the tool from the tip @ 1 to the part 2 of the maximum tool diameter is Δβ as shown in Fig. 1.
When drilling holes, the length Δl of the tip must be considered. In other words, when drilling a hole with effective depth D (the distance from the hole end face 3 to the deepest position with an inner diameter equal to the inner diameter of the hole end as shown in Figure 2), the tip of the tool should be moved to depth D. If it were moved, the cross-sectional shape of the hole would be as shown by the broken line 4 in the figure. Therefore, it is necessary to move the tip part deeper than D and process it into the shape shown by the broken line 5 in the figure.

Conventionally, when machining is performed using multiple tools with different tool lengths, the difference in each tool length is stored in memory as a compensation amount, and when machining is performed using tape commands, etc., the compensation amount is read and automatically executed. Although a so-called tool length correction device that automatically corrects the tool length has been known, it has not been done to automatically correct the length of the tip. Therefore, the programmer has to take into account the length of the tip in advance when creating the nitrogram. Furthermore, since the length of the tip usually differs when the tool diameter differs, it was necessary to change the program values for each tool.

Purpose of the Invention The present invention improves these conventional drawbacks, and
The purpose is to provide a cutting edge position correction device that automatically corrects the length of the tip of a tool.

Embodiment of the Invention FIG. 3 is a block diagram of essential parts of an embodiment of the present invention, and FIG. 4 is an explanatory diagram of tool length measurement. For example, four tools 41 are attached to the tool rest 40, and each tool number TO -T3 is applied, when a measurement command such as a program command or a command by key scanning is applied to the control circuit 30, the tool 41 with the tool number TO is first controlled so as to face the detector 42. This detector 42 utilizes pressure, optics, magnetism, etc., and generates a signal when the tip of the tool 41 makes contact or reaches a reference point. When the tool 41 with tool number TO faces the detector 42, the oscillator 31
The pulses from are supplied to a pulse motor drive circuit (not shown) as a distribution pulse leaf, and the tool rest 40 is moved by the pulse motor (not shown) until the tip of the tool 41 contacts the detector 42 and a detection signal SDT is obtained.

The distribution pulses at this time are counted by the counter 32, and when the detection signal SDT is obtained, the control circuit 30 stops the pulses from the oscillator 31, stops the counter 32 from counting, and also stops the feed of the tool post 40. Stop. The contents of the counter 32 at this time correspond to the distance β1, and the contents are stored in the tool length correction data area δ of the storage device 33 at the address corresponding to the tool number TO, and the tool rest 40 is returned to the initial position. Alternatively, the distribution pulse is supplied while subtracting the contents of the counter 32, and the tool rest 40 is retreated until the contents become zero, that is, to the original position.

When the above-mentioned operation is completed, the control circuit 30 rotates the tool rest 40 and causes the tool 41 with tool number T1 to face the detector 42. Then, in the same way as described above, the counter 32 counts the distribution pulses until the tip of the tool 41 with the tool number T1 contacts the detector 42 and the detection signal SDT is obtained, and the content is stored at the address corresponding to the tool number 1"l. This is stored in the tool length correction data area δ.If the same processing is performed on all the tools in the tool post 40 one after another in this way, the tool length correction amount of the tool 41 with the tool number 1'0-T3 will be stored in the storage device 33. δ0～δ
3 will be stored.

That is, the tool length 12 is calculated from the distance i3 from the center of the tool rest 4o to the detection surface of the detector 42, and the tool rest 42 is determined by the detection signal SD.
It is also possible to directly store the tool length in the storage device 33 by calculating the distance traveled until T is obtained + 1ill β1, but as mentioned above, the tool length is
If the contents of , are stored, the difference with a small number of digits will be stored.

FIG. 5 shows an expanded view of the tool 41 shown in FIG.
The amount of movement until the detection signal SDT is obtained, that is, the differences δ0 to δ3 with respect to the reference point, are automatically stopped by adding the measurement command old mentioned above. In this case, for example, if the tool with tool number TO is used as a reference, other tool numbers 11
The difference between the tool numbered T3 and the tool numbered TO is completely calculated.

Further, a standard rod or the like may be used instead of the tool with tool number TO.

Next, the tool numbers TO to T shown as Δβ0 to Δ13 in FIG.
Note the tip length of each tool in 1. Let Q. This can be stored via a manual data input device (keyboard) of the numerical control device (not shown).

The blade edge position correction is performed as follows.

In the third step, the control circuit 30 that has been given the tape command TP reads the contents of the command, and temporarily stores the movement command value of the tool in the drilling direction (Z-axis direction) in the register 34.

Also, when a tool number is commanded by tape command Tl+,
The adder 3 adds the tool length correction data and the tip long sleeve correction data stored at the address corresponding to the tool number in the storage device 33.
5, and the adder 35 adds both correction data to create blade edge position correction data. Then, the blade edge position correction circuit 36 corrects the command value set in the register 34 using this blade edge position correction data (actually adds the blade edge position correction data to the movement command value), and stores the corrected command value in the register 36. Then, according to the contents of this register 36, a distribution pulse signal is sent to a Z-axis motor drive circuit (not shown).

For example, when drilling a hole with an effective depth D, according to the present invention, if the effective depth D is programmed, the tip of the tool will be automatically positioned deeper by the length of the tool tip. Furthermore, even when using a plurality of tools with different tool tip lengths, the command value to be programmed can always be the same as the effective depth, so there is an advantage that programming can be made very easily.

In addition, when using a polling tool as shown in FIG. 6, for example, the length Δl from the tool tip to the maximum diameter portion of the tool may be stored in the storage device 33 as the tool tip length.

Further, when the tool length is not corrected, the tool length correction data area δ of the storage device and the adder 35 can be omitted.

DETAILED DESCRIPTION OF THE INVENTION As described in detail, the present invention includes a storage means for storing the tip length of each tool in correspondence with the tool number of each tool, and a storage means for storing the tool movement command value in correspondence with the tool number of the tool. Since it is equipped with a correction means that corrects the tool tip length stored in the storage means, it is possible to create command values by considering only the effective depth at the programming stage, making it extremely easy to create command programs. There are advantages to becoming

[Brief explanation of drawings]

FIGS. 1 and 2 are diagrams explaining the necessity of correcting the tip length of the tool, and FIG. 3 is a block diagram of the main parts of an embodiment of the present invention.
FIG. 4 is an explanatory diagram of tool length measurement, FIG. 5 is a developed view of the tool 41 shown in FIG. 4, and FIG. 6 is a plan view of poling. 33 is a storage device, 34 is a register into which a movement command value is stored, and 36 is a blade edge position correction circuit constituting a correction means. Patent applicant: Fanasoku Co., Ltd. Representative Patent attorney Hisaku Tamamushi 2 people 1 @ Figure 2 - Figure 3 Figure 4 Figure 5

Claims (1)

[Claims] A storage means for storing the length of the tip of the tool in correspondence with the tool number of the tool, and a tool movement command value corrected by the tool tip length stored in the storage means in correspondence with the tool number of the tool. A tool cutting edge position correction device for a numerically controlled machine tool, characterized by comprising a correction means.