JPH11104936A - Machine tool - Google Patents

Abstract

PROBLEM TO BE SOLVED: To measure the temperature of a heat generation part easily for a short time and improve the positioning accuracy of a relative moving part. SOLUTION: In a machining center, a non-contact type ultrared radiation temperator meter 9 for measuring the temperature of a work 1 is installed on the side of a main spindle head 4. A basic temperature sensor 10 for measuring the basic temperature is installed on a bed 7 which is a normal temperature part. The main spindle 4 is moved and the temperature of the plural places of the work 1 is measured by the ultrared radiation temperature meter 9 and a heat displacement is corrected based on the temperature difference between the work 1 and the bed 7. It is acceptable that the temperature measuring tool built in the ultrared radiation temperature meter is installed to a main spindle 8 attachably/detachably and replaced by ATC automatically.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for improving the positioning accuracy of a relative moving portion in a machine tool.

[0002]

2. Description of the Related Art Generally, in a machine tool, when one of two relatively moving members generates heat, a positioning error occurs between the two members due to a difference in thermal expansion. For example, in the machining center, as shown in FIG. 6, when the work 1 is heavy-cut with the tool 2, the work 1 and the table 3 generate heat.
The spindle head 4 and the Y-axis 5 distant from the cutting portion generate little heat. For this reason, a positioning error occurs due to a difference in thermal expansion between the member on the workpiece 1 side and the member on the tool 2 side, which adversely affects machining accuracy.

As shown in FIG. 7, when a work 1 such as a mold is finished cut by a tool 2, the work 1 and the table 3 hardly generate heat because of a small cutting amount. The Y-axis 5 and the sliding surface 6 generate heat with the repetitive movement of Step 4. Therefore, also in this case, a positioning error due to a difference in thermal expansion occurs.

Therefore, there has been proposed a technique for estimating the amount of thermal displacement of a heat generating portion and correcting the relative movement amount of the heat generating portion and a member facing the heat generating portion. In estimating thermal displacement, it is necessary to measure the temperature of the heating part.Conventionally, a thermocouple or thermistor is embedded in a heating part such as a table, or a hand-held sensor is brought into contact with the heating part, The temperature was being measured.

[0005]

However, the buried type sensor has a problem that it is not easy to change the installation location and the number of measurement locations is limited. In the case of a hand-held sensor, the measurement operation is troublesome, and a waiting time is required until the sensor becomes equal to the temperature of the heat generating part. There were problems such as measurement errors and the inability to automate the correction system.

An object of the present invention is to provide a machine tool which can easily measure the temperature of a heat generating portion in a short time and can position a relative moving portion with high accuracy by an automatic correction system.

[0007]

In order to solve the above-mentioned problems, a machine tool according to the present invention includes a non-contact type temperature sensor for measuring the temperature of a heating section on a member which is movably opposed to the heating section. (Claim 1).

The machine tool according to the present invention is a non-contact type temperature sensor for measuring the temperature of the heat generating portion on a member which is relatively movably opposed to the heat generating portion in order to enable the thermal displacement correction of the relative moving portion. , A reference temperature sensor for measuring a reference temperature is installed in the room temperature section, and a control device for correcting the relative movement amount of the heating section and the opposing member based on the output of each sensor is provided (claim 2).

In particular, in order to measure the temperature of the heat-generating portion at a machining point in a short time and with high accuracy, the machine tool of the present invention is a non-contact type temperature measuring device for measuring the temperature of the work on a spindle which is relatively movable with respect to the work. A temperature measuring tool provided with a sensor is detachably mounted (claim 3).

Further, in order to improve the machining accuracy, the machine tool of the present invention makes it possible to detachably attach a temperature measuring tool provided with a non-contact type temperature sensor for measuring the temperature of the work on a spindle which can move relative to the work. Attachment, a reference temperature sensor for measuring a reference temperature in the room temperature section is provided, and a control device for correcting a relative movement amount of the workpiece and the spindle based on an output of each sensor is provided (claim 4).

Here, as the non-contact type temperature sensor, an infrared radiation thermometer can be preferably used because high measurement accuracy can be obtained.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. 1 to 3 show an embodiment in which the inventions of claims 1, 2 and 5 are applied to a portal machining center. As shown in FIG. 1, in this machining center, a work 1 which is a heat generating part is placed on a table 3, and the table 3 is supported on a bed 7. The tool 2 for processing the work 1 is held at the lower end of the spindle 8,
Are rotatably supported by the spindle head 4.

The spindle head 4 is a member opposed to the work 1 so as to be relatively movable, and the Y-axis 5 is driven by a motor (not shown).
Is moved left and right along the sliding surface 6 of the cross rail. In this embodiment, a non-contact infrared radiation thermometer 9 for measuring the temperature of the work 1 is attached to the side surface of the spindle head 4, and a reference temperature is measured on the bed 7 which is a room temperature part. A reference temperature sensor 10 is provided.

As shown in FIG. 2, the infrared radiation thermometer 9
A lens 11 for collecting infrared rays emitted from the surface of the work 1, a thermopile 12 for converting the collected infrared rays into an electric signal, and an amplifier circuit 13 for amplifying the electric signal; Is configured to output the temperature of the work 1 as data based on.

The use of a plurality of infrared radiation thermometers 9 is advantageous in that a plurality of points on the work 1 can be measured in a short time. The infrared radiation thermometer 9 is installed at the spindle head 4
The present invention is not limited to this, and may be anywhere as long as infrared rays from the work 1 can be incident. As the reference temperature sensor 10, a normal contact sensor such as a thermocouple or a thermistor can be used. The reference temperature sensor 10 is attached to the bed 7.
However, the present invention is not limited to this, and may be another part of the bed 7 or a normal temperature part of a machining center other than the bed 7.

The control device of the machining center includes a thermal displacement correction system for correcting the relative movement amount of the work 1 and the tool 2 based on the outputs of the infrared radiation thermometer 9 and the reference temperature sensor 10. As shown in FIG. 3, the correction system 15 includes a circuit 16 for outputting a temperature measurement command, a circuit 17 for adjusting the measurement position of the infrared radiation thermometer 9, and a circuit 17 based on the output of the infrared radiation thermometer 9. A circuit 18 for calculating temperature data of the heat generating portion, that is, the work 1, a circuit 19 for performing arithmetic processing such as averaging the temperature data, and a reference temperature sensor 10
And a circuit 21 for calculating a difference between the temperature of the heating section and the temperature of the normal temperature section based on the output of the normal temperature section, that is, the reference temperature of the bed 7.

The correction system 15 includes a circuit 22 for generating a thermal displacement correction command in accordance with the calculation result of the temperature difference.
A circuit 23 for setting a correction scale suitable for the temperature difference;
A circuit 24 for outputting a required NC axis command read from the machining program, and a circuit 25 for generating new NC axis control data by integrating the correction scale and the NC axis command are provided.

According to the machining center configured as described above, the non-contact infrared radiation thermometer 9 is attached to the spindle head 4 which is movably opposed to the work 1. In addition to automatically measuring the temperature of a large number of parts of the work 1 with the movement in a short time, the position of the tool 2 can be automatically corrected accurately based on the temperature difference between the work 1 and the bed 7 to improve the processing accuracy. It is possible. Further, if the infrared radiation thermometer 9 is used, it is not necessary to stop the machine at the time of measurement or to make the spindle head 4 accurately follow the shape of the work 1, so that accurate temperature data can be collected during processing. There is also an advantage that real-time thermal displacement correction can be performed and the operation rate of the machining center can be improved.

FIG. 4 shows another embodiment in which the inventions of claims 1, 2 and 5 are applied to a portal machining center. The same members as those in the embodiment of FIG. 1 are denoted by the same reference numerals. ing. In this machining center, an infrared radiation thermometer 9 is mounted on the spindle head 4 so as to face the sliding surface 6 of the cross rail. Is to be measured. According to this configuration, in particular, when finishing the work 1 such as a mold, the temperature of the sliding surface 6 that easily generates heat with the repetitive movement of the spindle head 4 is accurately measured by the infrared radiation thermometer 9, The position of the tool 2 can be accurately and automatically corrected based on the temperature difference between the sliding surface 6 and the bed 7, and the finishing accuracy can be improved. The measurement site is not limited to the sliding surface 6, but can be represented by a temperature near this site.

FIGS. 5 and 6 show an embodiment in which the inventions of claims 3, 4, and 5 are applied to a portal machining center. In this machining center, as shown in FIG. 4, a temperature measuring tool 27 for measuring the temperature of the work 1 is detachably attached to the lower end of the main shaft 8 which can move relatively to the work 1. As shown in FIG. 5, the temperature measuring tool 27 has a built-in infrared radiation thermometer 9 similar to that of the above-described embodiment, and a transmitter 28 for wirelessly transmitting the measurement data. Further, the temperature measuring tool 27 is provided with a shank portion 27a similar to a normal tool, and the temperature measuring tool 27 is connected to an ATC (not shown).
This allows automatic exchange between the spindle 8 and a tool magazine (not shown). Receiver 2 near main shaft 8
9 is provided, receives the temperature data sent from the transmitter 28, and receives the same thermal displacement correction system 15 as in the above-described embodiment.
(See FIG. 3).

Therefore, according to the machining center of this embodiment, the temperature measuring tool 27 is attached to the main shaft 8 when necessary,
By moving the spindle 8, the temperature of many points of the work 1 can be automatically measured in a short time, and the position of the tool 2 is automatically corrected based on the temperature difference between the work 1 and the bed 7, thereby improving the processing accuracy. Can also be improved. Also, when measuring the temperature, the spindle 8 may be moved along the shape of the workpiece 1 when high accuracy is required, or the spindle 8 may be moved in a plane when the entire temperature distribution is required. There is also an advantage that the temperature measuring tool 27 can be moved along an arbitrary trajectory according to the type of the temperature information.

The present invention can be applied to various machine tools other than the machining center, and can also be applied to temperature measurement and thermal displacement correction of a relative moving portion other than a processing location. In addition, the present invention is not limited to the above-described embodiment, and can be implemented by appropriately changing the shape and configuration of each part without departing from the spirit of the invention.

[0023]

As described above in detail, according to the first aspect of the present invention, since the non-contact type temperature sensor for measuring the temperature of the heat generating portion is provided on the member facing the heat generating portion, the temperature of the heat generating portion can be reduced. There is an effect that measurement can be easily performed in a short time.

According to the second aspect of the present invention, since the control device for correcting the relative movement amount between the heat generating portion and the opposed member based on the outputs of the non-contact type temperature sensor and the reference temperature sensor is provided, the relative movement of the machine tool is provided. There is an effect that the portion can be positioned with high accuracy by the automatic correction system.

According to the third aspect of the present invention, since the temperature measuring tool having the non-contact type temperature sensor for measuring the temperature of the work is detachably attached to the main shaft, the temperature of the work can be easily measured in a short time. effective.

According to the fourth aspect of the present invention, the control device for correcting the relative movement amount between the workpiece and the spindle based on the outputs of the non-contact type temperature sensor and the reference temperature sensor is provided. Thus, there is an effect that positioning can be performed with high accuracy and processing accuracy can be improved.

According to the fifth aspect of the present invention, since the infrared radiation thermometer is used as the non-contact type temperature sensor, there is an effect that the temperature of the heat generating portion can be measured with high accuracy.

[Brief description of the drawings]

FIG. 1 is a front view of a main part of a machining center showing an embodiment of the present invention.

FIG. 2 is a schematic diagram showing an infrared radiation thermometer of the machining center.

FIG. 3 is a block diagram showing a thermal displacement correction system of the machining center.

FIG. 4 is a front view of a main part of a machining center showing another embodiment of the present invention.

FIG. 5 is a front view of a main part of a machining center showing still another embodiment of the present invention.

FIG. 6 is a schematic diagram showing a temperature measuring tool of the machining center.

FIG. 7 is an explanatory diagram of thermal displacement during heavy cutting.

FIG. 8 is an explanatory diagram of thermal displacement during finish cutting.

[Explanation of symbols]

1. Work, 2. Tool, 3. Table, 4. Spindle head, 7. Bed, 8. Spindle, 9. Infrared radiation thermometer, 10. Reference temperature sensor, 15. Thermal displacement compensation system, 27 .. Temperature measuring tool.

Claims (5)

[Claims] 1. A machine tool comprising a non-contact type temperature sensor for measuring a temperature of a heat generating portion provided on a member which is movably opposed to the heat generating portion. 2. A non-contact type temperature sensor for measuring the temperature of the heat generating part is provided on a member opposed to the heat generating part so as to be relatively movable, and a reference temperature sensor for measuring a reference temperature is installed in a normal temperature part. A machine tool provided with a control device that corrects a relative movement amount of a heating unit and an opposing member based on an output. 3. A machine tool comprising a temperature measuring tool provided with a non-contact type temperature sensor for measuring the temperature of a work on a spindle which is relatively movable with respect to the work. 4. A temperature measuring tool having a non-contact type temperature sensor for measuring the temperature of a work is detachably mounted on a main shaft which is relatively movable with respect to the work, and a reference temperature sensor for measuring a reference temperature is provided at a room temperature portion. A machine tool provided with a control device for correcting the relative movement amount of the workpiece and the spindle based on the output of each sensor. 5. The machine tool according to claim 1, wherein an infrared radiation thermometer is used as the non-contact type temperature sensor.