JPS62287956A - Edge point interference preventing device in edge point measuring device - Google Patents

Abstract

PURPOSE:To easily measure the edge point of a tandem tool rest lathe, by providing a means, which generates a signal of resettability to the original point only when the edge point is placed in a predetermined area, and a means which decides a tool to pass through a different original point resetting route. CONSTITUTION:A probe Ps has sensor surfaces A, B, C, D of four directions. A register group 6 sets effective distance values from each sensor surface A, B, C, D to both limit lines of an original point reset safety area. An effective distance selecting means 7 selects an effective distance value, corresponding to a contact sensor surface, of the respective effective distance values. An area decision means 9, which compares two calculated area assigned values with the edge point position present value in the time of original point resetting after contact with the sensor surface, decides a tool to be located in the original point reset safety area. An extra tool decision means 10 decides the tool to be an extra tool from the edge point position present value in the time or contact with the sensor surface.

Description

[Detailed Description of the Invention] 3. Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a cutting edge interference prevention device in a cutting edge measuring device, and is particularly suitable for a touch sensor in a lathe with a comb-shaped tool rest, etc. This invention relates to a blade edge interference prevention device.

[Conventional technology]

Conventionally, in machine tools in which relative movement between a tool and a workpiece is performed depending on position commands from a numerical control device, data on the position of the tool tip relative to the machine origin is inputted before operation. For this reason, a cutting edge measuring device is often used as a tool presafeter. A typical example is one that detects the position of the cutting edge by bringing a tool into contact with the sensor surface of the probe, and the probe is usually equipped with sensor surfaces in four directions so that it can accommodate various tools.

For example, as shown in FIG. 6, a plurality of tool boulders T1 are mounted on a tool rest Tr driven in two axes in the X direction and the Z direction.
~Thn is fixed in the same direction, and different types of tools T, x
In the case of a comb-type turret lathe that processes a workpiece W gripped by the jaws of a chuck C attached to the spindle S on the opposite side with Tn mounted on each side, the position of the cutting edge of each tool is set before machining. , transfer the cutting edge measuring device to the processing area. Next, the tool rest Tr is moved to the left in the figure, and the cutting edge of the tool is brought into contact with the sensor surfaces A, B, C, and D of the probe Ps. (Note that all the tools in the tool post move together.) [Problem to be solved by the invention] As described above, when measuring the cutting edge of a comb-type tool post lathe, the measurement of one tool is finished and the next tool is moved. When returning the tool post to its home position for measurement, the safe area where no interference will occur even when activated is not just a matter of moving away from the vicinity of the probe;
If it is too far away, interference with tools on both sides must be taken into consideration, so the scraping is limited to a narrow range. Furthermore, the tools used in comb-type turret lathes do not only have cutting edges facing in the same direction, but also tools that have unique probe contact paths and origin return paths, so a safe starting area must be provided separately. Must be.

The present invention was devised in view of these problems, and an object of the present invention is to provide a cutting edge interference prevention device suitable for measuring the cutting edge of a comb-type tool post lathe.

[Means for solving problems]

The measures taken in the present invention to solve the above-mentioned problems are as follows: Cutting edge interference in a cutting edge measuring device that measures the position of a tool cutting edge using a plurality of sensor surfaces in a machine tool that receives numerical commands to move the tool relative to the workpiece. The prevention device includes a register group in which an effective distance value of a home return safety area from each sensor surface is set, and an effective distance selection means for selecting an effective distance value corresponding to a contact sensor surface from among each effective distance value. Area specified value calculation means that subtracts the selected effective distance value from the current value of the blade edge position when the sensor surface is in contact, and compares the calculated area specified value with the current value of the blade edge position when returning to the origin after contacting the sensor surface. This is a cutting edge interference prevention device that is equipped with an area determination means that determines that the area is within the home return safe area. and special tool determination means for determining whether the tool is a special tool from the current position value, and depending on the determination result, which of the effective distance values corresponding to the normal tool is adopted as the effective distance value corresponding to the special tool. This is a blade edge interference prevention device that can be switched.

Note that in this specification, a special tool refers to a tool for which a return-to-origin path unique to a specific sensor surface is set in order to avoid interference.

[Effect]

In a comb-type tool post lathe having a contact-type cutting edge measuring device, the present invention sets a predetermined safety area, and enables origin return (or fixed point return) only when the cutting edge is within the safety area. .

As a characteristic of the comb-type tool post lathe, the return-to-origin operation during measurement is performed only in the X-axis direction shown in FIG. 6, and not in the X-axis direction. Therefore, the safe area can be set by setting the distance in the X-axis direction from each sensor surface to both the far and near limits of the safe area. Two effective distance values are set for each sensor cycle, and the effective distance value corresponding to the sensor surface that actually contacts is selected. If it is confirmed that the distance is between the effective distance values, a Z-direction home return possible signal is issued.

For special tools, a dedicated effective distance value is set, and the contact position of the cutting edge can be almost predicted for each tool. Therefore, by setting parameters in advance, a special tool can be determined, and if the determination result is a special tool, It is assumed that a Z direction home return possible signal is issued using a dedicated effective distance value.

〔Example〕

Hereinafter, the present invention will be explained in detail with reference to examples and drawings thereof.

FIG. 1 is a schematic diagram showing an example of a blade edge interference prevention device in a blade edge measuring device embodying the present invention.

In FIG. 1, the blade edge interference prevention device includes a central processing unit (hereinafter referred to as CPU) 1, a display with a keyboard 2, its input/output board 2a, a control program memory 3, and a servo that drives the X axis of the tool rest. The motor 4, its amplifier 4a and interpolator 4b, and the servo motor 5° that drives the Z-axis of the tool post; its amplifier 5a and interpolator 5b and 1.4
Probe Ps with sensor surfaces A, B, C, D in the direction
, a register group 6 in which effective distance values from each sensor surface to both limit lines of the home return safety area are set, and effective distance selection means for selecting an effective distance value corresponding to the contact sensor surface from among each effective distance value. 7, area designation value calculating means 8 for subtracting the selected effective distance value from the current value of the blade edge position at the time of contact with the sensor surface, and the two calculated area designation values and the blade edge position when returning to the origin after contact with the sensor surface. Area determination means 9 that compares with the current value and determines that it is within the home return safe area.
and a special tool determining means 10 that determines whether the tool is a special tool from the current value of the cutting edge position when the sensor surface is in contact with the sensor surface.

The relationship between the above-mentioned effective distance value and both limit lines of the home return safety area will be explained for each sensor surface as follows.

FIG. 2(a) is an explanatory diagram showing the effective distance value of the sensor surface A. In the figure, since the sensor surface A faces in the +X direction, the safe Z-axis return-to-origin area is located above the probe in the figure, with the far limit line X1 and the near limit line x2.
It is set by

The near limit line X2 is the limit to avoid interference between contacting cutting edges, and the far limit line X is the limit to avoid interference between adjacent tools. In the present invention, the distance from these two limit lines X I and X2 to the sensor surface A is −X+ (A),
Set Xz (A) as the effective distance value of sensor surface A.

FIG. 2(b) is an explanatory diagram showing the effective distance value of the sensor surface B. FIG. In the same figure, since sensor surface B faces in the +Z direction, the safe Z-axis return-to-origin area is possible by setting two limit lines X1 and X2 in both the upper and lower directions of the probe to avoid interference between adjacent tools. good. In the present invention, the distance from the two limit lines X1 and x2 to the sensor surface B -x,
(B) and 1×2 (B) are set as the effective distance value of sensor surface B.

FIG. 2(c) is an explanatory diagram showing the effective distance value of the sensor surface C. In the figure, since the sensor surface C faces the -X direction, the area in which the probe can safely return to its origin is set by the near limit line X1 and the far limit line X2 at the bottom of the diagram. Ru.

The near limit line X1 is the limit to avoid interference between contacting cutting edges, and the far limit line X2 is the limit to avoid interference between adjacent tools. In the present invention, these two limit lines X1 and X
Distance from 2 to sensor surface C +XI (c), +
Set xz (c) as the effective distance value of the sensor surface C.

FIGS. 2(d) and 2(e) are explanatory diagrams showing effective distance values of the sensor surface. In both figures, since the sensor surface faces in the -Z direction, the safe Z-axis return-to-origin area is set above or below the probe in the figures, depending on the origin-return path of the cutting edge. Normally, the region in the upper part of the figure where return to origin is possible shown in Figure (d) is set for general tools, and the distances from the far limit line X1 and the near limit 41X1 to the sensor surface are -X+ (D) and - x, (D)
is set as the effective distance value of the sensor surface, and in addition, the area where the origin can be returned in the lower part of the figure shown in Figure (e) is set as a special tool, and the near limit line x1 and the far limit line X2 are set. Distance from and to sensor surface +X+(D')
and 10×2(D') is set as the effective distance value of the sensor surface.

Now, each of the above effective distance values is a distance value from the sensor surface, and what is actually measured is the current value of the cutting edge position from the machine origin O, l, so calculation and comparison judgment in the present invention is based on the coordinate values. must be processed. FIG. 3 is a diagram explaining the relationship between them using an example of sensor surface A. If the current value of the blade edge position at the time of blade edge contact is Xps,
The X coordinate values of the two limit lines X1 and X2 from the machine origin 04 are X a = Xps X + (A)X b
= Xps Xz (A). Next, after the cutting edge contacts, move the tool from the sensor surface and set the current value of the cutting edge position when returning to the origin as Xp, and compare it with this Xp, Xb<Xp<Xa (Xa, Xp, Xb are negative values)
If so, it can be determined that return to origin is possible.

These calculations and comparative judgments are performed by the blade edge interference prevention device of this embodiment shown in FIG. 1, and FIG. 4 is a flowchart showing its operating procedure. Hereinafter, the above device will be explained in detail according to the UJ operation procedure.

As the 0th stage of the flow, first, the probe Ps is brought into contact with the tool cutting edge. The input from each sensor surface is made into an independent circuit, and the signal "l" is input to only one of the AND gates 71 to 75 in the effective distance selection means 7, and as the 0th stage of the flow, From register group 6,
Only effective distance values corresponding to the touch sensor surface are retrieved. On the other hand, the current value Xp of the current cutting edge position is always in register 1.
01, and the current value of the cutting edge position at the time of contact Xp
s is input to the area designation value calculation means 8 via the AND gate 102, and as the 0th stage of the flow, the selected effective distance values X1 and XZ are subtracted, and as the 2nd stage of the flow,
The region designation coordinate values Xa and Xb are determined. With the blade edge position as it is, the area other than sensor surface B is outside the safe area, so it is manually moved to a position that is estimated to be in the safe area, and as the 0th stage of the flow, the current value Xp of the blade edge position is taken into the register 101. Input to area determination means 9,
A comparison of p<Xa is made, and if the current value Xp of the cutting edge position is within the range, a Z-direction origin return possible signal is issued as the 0th stage of the flow, and an automatic return operation is performed as the 0th stage of the flow. If the current value of the cutting edge position
The comparison of Xb<Xp<Xa in the rows will be redone.

Note that it is generally more convenient to make these operations effective only when the sensor arm is lowered to the measurement position.

By the way, when the contact position is on the sensor surface, as already explained, there are two return paths, one above the probe and the other below, so one is for general tools and the other is for special tools. For tools, the present invention has an effective distance value of 2
I decided to register them in separate registers. The special tool determining means 10 registers predicted contact coordinate values and their allowable errors with respect to the sensor surface for each special tool, and compares them with the current value of the cutting edge position Xp.

Figure 5 is an explanatory diagram showing the principle of the recognition method, and Figure (a)
As shown in , when a plurality of tools are fixed to one tool post, for example, the distance Xi from the machine origin Os to the cutting edge of tool Ti and the distance Xj to the cutting edge of tool Tj always have a predetermined interval. This measurement does not measure completely unknown data, and the contact coordinate values are approximately predictable, and are measured to correct minute deviations due to workpiece changes or setup changes, for example. As shown in Figure (b), the predicted contact coordinate value X also applies to special machining. , can be easily set. Needless to say, the predicted contact coordinate value XDP
It is necessary to provide a tolerance ±Xz, and it is safer if the tolerance Xz is larger than the radius of the sensor surface. When the blade edge contacts sensor D, (XDP-XZ)<Xp< (XDP+
XZ) is compared, and if Xp is within the above range, a signal indicating that the tool is a special tool is output.

If it is a special tool, a signal "" is sent to the AND gate 75.
1" is input, and the signal "0" is input to the AND gate 74, so the effective distance value for the special tool is selected,
If Xp is not within the above range and the tool is not a special tool,
A signal "1" is input to the AND gate 74, and the AND gate 74 receives the signal "1".
Since the signal "0" is input to the gate 75, the effective distance value for the general tool is selected. The flow from selecting the effective distance value to outputting the home return possible signal follows the flowchart in FIG.

This method can be applied to devices that have two cutting edge positions on the shank, and the way the cutting edge is released differs depending on the position, and has a wide range of applications.

〔Effect of the invention〕

As explained above, according to the present invention, a means for emitting a return-to-origin possible signal is provided only when the cutting edge is within a predetermined area, and a means for determining which tools pass through different return-to-origin paths is provided, thereby ensuring safety and safety. It is possible to provide a cutting edge interference prevention device that is easy to operate and suitable for measuring the cutting edge of a comb-type tool post lathe.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing an example of a cutting edge interference prevention device implementing the present invention, Fig. 2 is an explanatory diagram of each effective distance value, Fig. 3 is an explanatory diagram of the principle of the present invention, and Fig. 4 is an example of the above embodiment. FIG. 5 is an explanatory diagram of the special tool determination principle, and FIG. 6 is an explanatory diagram of a conventional example. 1. CPU (Central Processing Unit), 2. Display with keyboard, 6. Register group, 7. Effective path M selection means, 8. Area designation value calculation means, 9. Area determination means, lO. Special tool determination means, Xp ; Current tip plate coordinate value, Xps; Cutting tip plate coordinate value at the time of contact.

Claims (2)

[Claims] (1) A cutting edge interference prevention device in a cutting edge measuring device that measures the cutting edge position of a tool of a machine tool that receives numerical commands for relative movement between the tool and the workpiece using multiple sensor surfaces, and has a safety area for returning to the origin from each sensor surface. a group of registers in which effective distance values are set; effective distance selection means for selecting an effective distance value corresponding to the contacted sensor surface from each effective distance value;
Area specified value calculation means that subtracts the selected effective distance value from the current value of the blade edge position when the sensor surface is in contact, and compares the calculated area specified value with the current value of the blade edge position when returning to the origin after contacting the sensor surface. 1. A cutting edge interference prevention device in a cutting edge measuring device, characterized in that the cutting edge interference prevention device is provided with an area determining means for determining that the area is within a home return safe area. (2) Equipped with a register in which an effective distance value corresponding to a special tool is set, and a special tool determination means that determines that the tool is a special tool from the current value of the cutting edge position when the sensor surface is in contact, and the determination result is Claim 1, characterized in that it is possible to switch between adopting an effective distance value corresponding to a special tool or an effective distance value corresponding to a normal tool.
A blade edge interference prevention device in the blade edge measuring device described in 2.