JPS582790B2 - Jido Hasaki Kenshiyutsu Sochi - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an automatic cutting edge detection device that can be used in machine tools, particularly so-called automatic machines, to achieve high machining accuracy and improved machining efficiency.

So-called automatic machines such as copying machine tools have been widely used as a labor-saving measure.When machining a large number of workpieces of the same shape and size, these automatic machines move the workpieces away from their reference home position. By repeatedly moving the machine along a predetermined machining path, a finished product is obtained from the raw material, saving labor from repeated setting work performed by the operator and improving work efficiency.

It is therefore known to use cutting edge detection devices in order to correctly return the workpiece to its reference origin in each case.

That is, for example, in a copying lathe, a cutting edge detection device having a cutting edge detection reference surface is provided on the tailstock, and each time a machining process is completed, the cutting edge is brought into contact with this cutting edge detection reference surface, and the template is The tip of the stylus is brought into contact with the upper machining starting point, the machining starting point of the template and the cutting edge of the tool are once aligned, the tool origin is detected, and the next machining process is started from the tool origin.

In such conventional cutting edge detection devices, it is necessary to detect the cutting edge in advance in order to avoid the causes of dimensional errors that always tend to be the same for a large number of workpieces, such as a decrease in the cooling effect due to the heat generated during machining or the warming of the cooling water. By manually displacing the cutting edge reference plane of the detection device, the tool origin can be shifted and the depth of cut of the tool can be adjusted to correct dimensional errors occurring in the workpiece.

However, such a conventional cutting edge detection device can immediately detect that the deviation of the tool origin is sufficient to reliably eliminate the dimensional error of the same tendency from the result of manually displacing the cutting edge reference plane as described above. It is impossible to confirm this, and the operator must repeatedly perform correction work by trial and error, which has the drawback that the intention of labor saving cannot be completely achieved.

Furthermore, conventional cutting edge detection devices do not have means to correct errors that cause dimensional errors to gradually increase with each machining process, such as wear of the tool cutting edge or deterioration of tool sharpness, so it is difficult to correct when processing a large number of products. Inevitably, defective products are produced periodically, and in order to deal with the occurrence of such periodic errors, manual correction work by the operator is required periodically, which is also a disadvantage that goes against the purpose of labor saving. Become.

Therefore, the purpose of the present invention is to improve the labor-saving function and work efficiency by eliminating the drawbacks of the conventional blade edge detection device in automatic machines, and to achieve an improvement in the yield of passed products and improvement in processing accuracy. An object of the present invention is to provide a cutting edge detection device.

That is, according to the present invention, the tool origin is automatically detected by bringing the tool edge into contact with the tool reference plane after machining of the workpiece is completed, and the tool is restarted from the tool origin to machine the subsequent workpiece. In the device, the tool reference plane is configured to be movable, and a tool reference plane movement amount detection means is provided to detect the amount of movement thereof, and the deviation between the dimensions of the workpiece and the target dimensions after machining is completed is detected. A comparison means for comparing a workpiece dimension deviation signal sent out as feedback from the workpiece size measurement means and a tool reference plane position signal sent out from the tool reference plane movement amount detection means. , the tool cutting edge is pushed toward the tool reference surface and brought into contact with the tool reference surface, and the tool reference surface is corrected and moved in the comparison means until the workpiece dimensional deviation signal and the movement amount signal of the tool reference surface position match. automatic cutting edge detection characterized in that the position of the tool origin is automatically corrected in advance by correction movement of the tool reference plane, and machining of a subsequent workpiece is restarted from the corrected tool origin. Equipment is provided.

Hereinafter, the present invention will be described in detail based on embodiments shown in the accompanying drawings.

FIG. 1 is a side view schematically showing the main parts of an embodiment in which a copying lathe is equipped with an automatic cutting edge detection device according to the present invention.

In FIG. 1, the center 1 of the tailstock 11 of the copying lathe
A workpiece 15 to be cut from a material is hung between the center 3 and another center not shown in the figure.

Reference numeral 17 is a measuring instrument head for measuring the actual dimensions of the workpiece 15 relative to the target dimensions after the machining process is completed, and is installed on the copying lathe as a so-called post gauge.

The dimensions measured by the measuring instrument head 17 are converted into electrical signals and sent out from the lead wire 17a.

The tailstock 11 is provided with an operating section 20 of an automatic cutting edge detection device according to the present invention.

The operating unit 20 of this automatic cutting edge detection device is provided with a head 21 having a tool reference surface that comes into contact with the cutting edge of a cutting tool 25 and is movable in the vertical direction in the drawing perpendicular to the center line 19 of the lathe with respect to the differential transformer 23. It is made up of.

Therefore, the head 21 uses the lead wire 2 as an electrical signal based on the upward and downward positional displacement of the differential transformer 23 with respect to the electrical midpoint.
It is sent from 3a.

On the other hand, the cutting tool 25 is attached to the tool rest 27, and its cutting edge can be moved forward and into the tool rest 27 by a feed motor 29.

That is, the cutting edge of the cutting tool 25 is moved to the tool rest 27 according to the rotational direction of the feed motor 29 and the amount of cutting edge movement per step.
It is possible to enter and exit a predetermined amount at a time.

Now, the tool rest 27 is fixed on a copying device 31, and this copying device 31 has an arm 31a at its rear end.
A stylus 35 is fixed to 1a so as to be finely adjustable.

This stylus 35 is set on the tracing surface of the template 33 regarding the workpiece 15, and when the stylus 35 moves along the tracing surface of the template 33, the template 33
A workpiece 15 defined by the shape and dimensions of 3 is cut out of the material by the cutting action of the cutting tool 25.

The movement of the stylus 35 is done using a copying saddle (not shown).
This occurs in response to the movement of the copying device 31 caused by the automatic operation of the copying device 31.

Now, referring to FIG. 2, FIG. 2 is a block diagram illustrating the operation of the automatic cutting edge detection device according to the present invention.

As shown in the figure, an electric signal indicating the amount of displacement of the tool reference plane sent from the differential transformer 23 of the actuating section 20 via the lead wire 23a is amplified by the amplifier 51, and converted into a digital signal by the A-D converter 53. After being converted into , it is sent to the comparison circuit 55 .

On the other hand, the electric signal from the measuring instrument head 17 that measures the dimensions of the workpiece 15 after the completion of the machining process is amplified by the amplifier 41 via the lead wire 17a, and then converted into a digital signal by the A-D converter 43. and reversible counter 45
will be sent to

In the reversible counter 45, target dimension values for the workpiece 15 are stored in advance as digital values.

Therefore, the dimension of the workpiece 15 sent from the detector head 17 immediately after completion of machining is determined by detecting the deviation from the target dimension value in the reversible counter 45, and passing the detected deviation to the comparison circuit 55 via the feedback correction path 47. is sent.

Further, this deviation amount is cumulatively added as a signed digital amount within a reversible counter, and when this cumulative addition amount reaches a certain value, the cutting edge tip 25 is replaced.

Now, according to the present invention, when the dimensions of the workpiece 15 are measured by the measuring device head 17 in the post process after the cutting of the workpiece 15 is completed, the workpiece 15
The deviation of the dimension value from the target dimension value is detected, and the detection result is immediately sent to the comparison circuit 55 via the feedback correction path 47 as described above.

Therefore, before starting the machining process of the subsequent workpiece, the feed motor 29
When the cutting edge 25' of the cutting tool 25 reaches the tool reference plane in the operating section 20 of the automatic cutting edge detection device and the tool origin of the cutting tool 25 is detected by an electric signal indicating the amount of displacement of the tool reference surface, the The feed motor 29 applies a feeding or feeding displacement to the cutting edge 25' of the piping tool 25 in advance by an amount corresponding to the dimensional deviation of the machined workpiece 150.

The feed-out displacement amount or the feed-in displacement amount applied to the cutting edge 25' of the cutting tool 25 is detected by the differential transformer 23 as the amount of movement of the reference surface of the head 21 with which the cutting edge is in contact, and is sent to the comparison circuit 55.

Therefore, from the comparison circuit 55, the processed product 15 processed immediately before
It is possible to match the dimensional deviation in and the displacement amount of the tool origin in the subsequent machining process.

When such a match is found, a match signal is sent to the feed motor drive circuit 57 to stop the rotation of the feed motor 29.

That is, according to the present invention, the cutting start origin of the cutting tool is corrected in advance just before machining the subsequent workpiece based on the measured dimension value of the workpiece 15 immediately after machining is completed, and as a result, the cutting of the subsequent workpiece 15 is corrected. This prevents dimensional errors exceeding allowable tolerances from occurring.

Of course, since the automatic blade edge detection function in the above-mentioned post process is achieved in a very short time via an electric signal circuit, the improvement in processing efficiency is significant.

In addition to this method of obtaining the amount of displacement of the tool reference plane using electrical signals, there is also a method in which the tool reference plane, which is composed of a touch switch, is mechanically moved by another motor, and the cutting edge 25' is aligned with the tool reference plane. It is also possible to obtain an electrical signal by bringing them into contact.

As is clear from the above explanation, according to the present invention, at the start of a machining process, the origin of the machining tools is automatically corrected in advance based on the actual measured dimensions of the workpiece that has been machined immediately before. As a result, since the subsequent workpiece is being machined, it is possible to achieve an automatic cutting edge detection function that takes into account the causes of machining errors that change over time, such as wear of the workpiece and deterioration of sharpness.

Incidentally, the cutting tool 25 performed by the motor 29 shown in FIG.
For the feeding and feeding operations, for example, a feed screw hole is provided inside the tool post 27 and is rotated by the feed motor 29 via a gear mechanism, and the eccentric wedge shaft is moved in the axial direction according to the rotation of the feed screw hole. A mechanism or the like in which the wedge angle and the cutting tool 25 are arranged so as to be linearly movable along an appropriate guide path according to the sliding amount by sliding can be applied.

Furthermore, although the above description has been made regarding an embodiment of an automatic cutting edge detection device installed in a copying lathe, it goes without saying that the technical idea of the present invention can be applied to various automatic machines such as drilling machines and grinding machines.

[Brief explanation of drawings]

FIG. 1 is a side view schematically showing the main parts of an embodiment in which a copying lathe is equipped with an automatic cutting edge detection device according to the present invention, and FIG.
The figure is a block diagram illustrating the operation of the automatic cutting edge detection device according to the present invention. In the figure, 11 is a tailstock, 13 is a center, 15 is a processed product, 17 is an inspection head, 20 is an operating part of an automatic cutting edge detection device, 21 is a head, 23 is a differential transformer, 25 is a cutting tool, 27 is a tool rest, 29 is a feed motor, 31 is a copying device, 33 is a template, 35 is a stylus, 41; 51
is an amplifier, 43; 53 is an A-D converter, 45 is a reversible counter, 47 is a feedback correction path, 55 is a comparison circuit,
57 is a feed motor drive circuit.

Claims (1)

[Claims] 1. In an automatic cutting edge detection device that automatically detects the tool origin by bringing the tool edge into contact with the tool reference surface after completing machining of a workpiece, and restarts the tool from the tool origin to machine the subsequent workpiece, the above-mentioned The tool reference plane is configured to be movable, and a tool reference plane movement detection means is provided to detect the amount of movement, and the workpiece dimension inspection is used to measure the deviation between the dimensions of the workpiece and the target dimensions after machining is completed. means for comparing a workpiece dimensional deviation signal fed back from said workpiece size measuring means and a tool reference surface position signal sent from said tool reference surface movement amount detecting means; a feeding means for pushing the tool reference surface into contact with the tool reference surface and correcting the tool reference surface until the comparison means matches the workpiece dimensional deviation signal and the movement amount signal of the tool reference surface position; An automatic cutting edge detection device characterized in that the position of a tool origin is automatically corrected in advance by correcting movement of the tool reference plane, and machining of a subsequent workpiece is restarted from the corrected tool origin.