JPH04112741U - Machine tool thermal displacement error reduction device - Google Patents

Abstract

(57) [Summary] [Purpose] To shorten the time for machine tools such as lathes to reach normal operating temperature after startup, and shorten the time for thermal displacement errors to occur. [Structure] A heater 16 for promoting thermal displacement is provided near the X-axis rail 5 of the bed 1 on which the turret tool rest 4 is installed. By actively heating with this heater 16, the normal operating temperature is reached in a short time at the start of operation, and operation is performed in a stable thermal displacement state. The heater 16 is provided not only in the bed 1 but also in any location where the position or posture relationship between the tool and the workpiece is subject to thermal displacement due to a temperature increase during operation.

Description

[Detailed explanation of the idea]

0001

[Industrial application field]

This idea is suitable for general machine tools such as lathes, machining centers, and punch presses. The present invention relates to a thermal displacement error reduction device used in the present invention.

0002

[Conventional technology]

Machine tools generally lose cutting heat and sliding of various parts over time after they start operating. The temperature of each part gradually rises due to frictional heat of the parts or heat generated by the drive source. This temperature increase reaches an equilibrium state in several tens of minutes to several hours due to natural heat radiation and the like.

0003 This temperature rise causes thermal displacement in the bed and other parts, and this thermal displacement This causes machining errors. For example, in a lathe, the turret can be moved due to thermal displacement of the bed. An error occurs in the moving distance, which causes the cutting depth and feed amount of the cutting tool to fluctuate, resulting in machining errors. occurs.

0004 For this reason, conventional methods have been used to suppress heat generation and use materials with small thermal displacement. Efforts are being made. In addition, the feed amount of the tool post is corrected depending on the elapsed operating time, temperature measurement results, etc. Things are being done.

[0005]

[Problem that the idea aims to solve]

However, there are limits to the prevention of heat generation and the suppression of thermal displacement through material selection, and Processing errors cannot be reduced. In addition, in the method of correcting the feed rate described above, the temperature rise period at the start of operation is The thermal displacement changes over time, and the rate of temperature rise also changes depending on processing conditions, etc. Since the degrees are different, it is difficult to perform appropriate correction.

[0006] For this reason, perform a warm-up operation and wait until the temporal fluctuations in the amount of thermal displacement have decreased before starting the actual application. However, it takes time for the temperature to rise during warm-up operation. This will reduce the operating rate. For example, if you start driving in the morning of the day, then start driving during your lunch break. If you stop the machine, it will be necessary to warm up the machine again, which will shorten the time that can actually be processed.

[0007] The purpose of this invention is to enable operation under stable temperature conditions and reduce thermal displacement errors. An object of the present invention is to provide a thermal displacement error reduction device for a machine tool.

[0008]

[Means to solve the problem]

The thermal displacement error reduction device of this invention is capable of reducing the temperature of the tool due to the temperature rise associated with the operation of the machine tool. Heater for promoting thermal displacement is installed in the area where thermal displacement is applied to the position or posture relationship between the It is equipped with a ta.

[0009]

[Effect]

According to this configuration, by actively heating with a heater, a short time is required at the start of operation. It can be raised to normal operating temperature between Also, after that, the machine tool remains constant. It can be operated at a certain temperature.

0010

【Example】

An embodiment of this invention will be described based on FIGS. 1 to 4. This example uses sauce. This is an example applied to a cut lathe.

[0011] A spindle 3 having a chuck for a workpiece W is supported on a spindle stock 2 installed on a bed 1, A turret tool rest 4 is installed adjacent to the headstock 2. The turret tool rest 4 is A base slide 6 that can freely run in the horizontal direction (X-axis direction) on the rail 5 on the top surface of the pad 1 A downward rail 7 is mounted on this base slide 6 so that it can move freely back and forth (in the Z-axis direction). The mounted cross slide 8 and the turret shaft 9 (Fig. 2) are connected to the cross slide 8. It consists of a turret 10 installed so that it can be indexed and rotated.

0012 The cross slide 6 is operated by a belt transmission mechanism by a motor 11 installed on the bed 1. 14 and the X-axis feed screw 12. The cross slide 8 A motor (not shown) installed on the base slide 6 drives the Z-axis through the Z-axis feed screw 13. It is driven forward and backward. The turret 10 is drum-shaped with a polygonal front shape. , a tool 15 such as a cutting tool or a rotary tool is attached to each peripheral surface portion.

[0013] In a turret lathe with such a basic configuration, the top plate of the bed 1 is A heater 16 for promoting thermal displacement is attached to the inner surface near the rail 5. Heater 6 consists of various types of electric heaters. The top plate of bed 1 is made of a material with good thermal conductivity. It is preferable to use In the illustrated example, the heater 16 is rod-shaped, but A planar material or the like may also be used.

[0014] The heater control device 17 turns on the heater 16 in response to the ON operation of the power switch 18. When heating starts and the measured value by the thermometer 19 reaches the set temperature, the heater 16 This is a means of stopping the heating of the The thermometer 19 measures the temperature of a predetermined portion of the top plate of the bed 1. It is used to measure degrees. Further, the heater control device 17 controls the temperature even after the heating is stopped. The heater 16 is controlled on and off so that a total of 19 detected values are maintained within the set temperature range. A means to do so has been added. In addition, use a timer instead of the thermometer 19 to start heating. After that, the heater 16 may be turned off after a certain period of time.

[0015] According to this configuration, the operation of the lathe is started by turning on the power switch 18. Heating by the heater 16 is started, and the temperature of the bed 1 reaches the set temperature (for example, When the normal operating temperature is reached, heating by the heater 16 is stopped.

[0016] After this, the temperature measured by the thermometer 19 becomes lower than the set temperature due to a temporary suspension of operation, etc. Then, the heater 16 is turned on again to heat the bed 1.

[0017] This thermal displacement error reduction device actively moves the bed 1 by the heater 16 in this way. For heating, the thermal displacement of bed 1 in the X-axis direction is normally shown by curve b in Figure 4. The thermal displacement rises faster until it reaches the thermal displacement E during operation. Curve a is the heater 16 is a curve showing the rise of thermal displacement when heating is not performed.

[0018] In this way, a stable thermal displacement state during normal operation can be reached in a short time, and the thermal displacement can be reduced over time. The amount of time it takes for the quantity to change becomes shorter. Therefore, machining due to incomplete correction of thermal displacement The time for errors to occur is shortened, and the number of workpieces W that produce machining errors is reduced. can do. In other words, the thermal displacement of the bed 1 in the X-axis direction is the thermal displacement of the turret 10. This is an error in the amount of movement in the X-axis direction, and an error in the amount of cut of the tool 15 into the workpiece W. This results in machining errors in the diameter of the workpiece W, but it is possible to reduce such machining errors. I can do it.

[0019] In addition, the turret slide 6 and the clock are heated by the heater 16 of the bed 1. The slide 8 is also heated and quickly reaches the thermal displacement state during normal operation. Therefore, Processing errors in the Z-axis direction of the workpiece W can also be reduced.

[0020] Furthermore, even after the normal operating temperature is reached and the heater 16 is turned off, the operation may be temporarily interrupted. If the temperature drops due to a disconnection, etc., turn on the heater 16 again to return the bed 1 to normal. It can be heated to operating temperature and always operated within a constant temperature range. by this Also, machining errors due to thermal displacement can be reduced.

[0021] In the above embodiment, the heater 16 was installed on the bed 1, but the feed screw of each axis 12 and 13 may have built-in heaters, or the turret tool rest 4 may be provided with a heater. It's okay. Furthermore, although the above embodiment has been explained with reference to the case where it is applied to a lathe, this invention is applicable to a machine tool. Applicable to general machines, such as workpiece feeding mechanisms in punch presses and machining. It can also be applied to a spindle head feeding device in a center.

[0022]

[Effect of the idea]

The machine tool thermal displacement error reduction device devised by this invention is designed to reduce the temperature rise caused by machine tool operation. Thermal displacement is induced in the area where thermal displacement is applied to the position or posture relationship between the tool and the workpiece. A heater has been installed to actively heat the vehicle at the start of operation. The temperature can be raised to normal operating temperature in a short period of time. Also, it remained constant after that. It can be operated while maintaining the temperature. These allow machining due to thermal displacement over time. This has the effect of reducing errors.

[Brief explanation of drawings]

FIG. 1 is a cutaway front view of a lathe to which an embodiment of the present invention is applied.

FIG. 2 is a schematic plan view of the lathe.

FIG. 3 is an enlarged cutaway side view of the lathe.

FIG. 4 is an explanatory diagram showing thermal displacement curves when the heater is heated and when it is not heated.

[Explanation of symbols]

1... Bed, 2... Headstock, 3... Main spindle, 4... Turret turret, 5... Rail, 6... Turret slide, 8... Cross slide, 10... Turret, 12... X-axis feed screw, 13...
Y-axis feed screw, 16...Heater

Claims (1)

[Scope of utility model registration request] 1. A thermal displacement error reduction device for a machine tool, in which a heater for promoting thermal displacement is provided at a portion where thermal displacement is caused in the position or posture relationship between the tool and the workpiece due to a temperature rise accompanying operation of the machine tool.