JP2003266209A - Machining device and machining method, and method for prolonging tool service life - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a technique capable of decreasing a friction speed of a tool, reducing the frequency of tool replacement, and enhancing machining efficiency. <P>SOLUTION: The machining device comprises a tool holder 1, a tool 2 held by the tool holder, and a Peltier element 3 provided so as to contact with the tool. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for a tool such as a cutting tool, a machining method, and a tool life extension method.

[0002]

Generally, under the conditions of high-speed cutting / turning, the temperature of the tool rises due to friction with the work material during processing. This temperature rise is
This results in a decrease in cutting edge strength (mostly melting), further shortening the tool life. For example, when high-speed turning of gray cast iron is performed using a binderless cBN tool, the following is reported (Shinya et al., 200
Proceedings of the 0th Annual Meeting of Japan Society for Precision Engineering, Academic Conference 204
Pp. Shintani et al .; Proc. Of the 2001 Spring Meeting of the Japan Society for Precision Engineering. That is, 6.67
In the relatively low cutting speed range such as 33.33 m / s, the life of the cBN tool is relatively long. However, at high cutting speeds exceeding 41.00 m / s, cBN
The tool wear becomes severe, especially when the continuous cutting time exceeds a certain time, the wear of the cBN tool becomes extremely severe.

[0003] By the way, when the tool is inexpensive, it is conceivable to set the life in advance with a margin and replace the tool early so as to prevent the machining efficiency from being lowered.

However, a tool using diamond or cBN as a tool material is expensive and cannot be easily replaced.

Therefore, the problem to be solved by the present invention is to provide a technique capable of slowing the wear rate of the tool, extending the life of the tool, reducing the number of times of tool replacement, and improving the machining efficiency.

In particular, when a binderless cBN or diamond tool is used, the wear rate of the tool is slowed, the life of the tool is extended, the number of times of tool replacement is reduced,
It is to provide a technique capable of improving processing efficiency.

[0007]

The above problems include a tool holder, a tool held by the tool holder, and a Peltier element provided so as to abut the tool. Solved by the device.

In particular, it is provided with a tool holder, a tool held by the tool holder, a Peltier element provided so as to abut the tool, and a heat sink provided on a heat radiation surface of the Peltier element. It is solved by the characteristic processing device.

A machining method using the above-mentioned machining apparatus is characterized in that a voltage is applied to the Peltier element at the time of machining to cool the tip of the tool.

A method of extending the life of a tool for extending the life of the tool using the above-mentioned machining apparatus, characterized in that a voltage is applied to the Peltier element to cool the tip of the tool during the machining. It is solved by the life extension method.

That is, it has been found that the increase in the wear rate of the tool (short tool life), which is largely caused by the increase in the processing speed, is largely due to the heat generation (temperature rise) occurring during the processing. For example, the cutting speed V is 41.67.
When the cutting is continued under the condition of m / s, the average temperature θm of the cutting edge becomes 1620K which is the deterioration start temperature of RcBN (binderless cBN). In the RcBN tool, the tool blank is small, and heat shielding occurs at the end of the blank that is in contact with the cemented carbide tool portion of the base (base).
It was thought that heat was accumulated in the blank portion and the temperature of the cutting edge was likely to rise.

Therefore, a cutting temperature control system for suppressing a rise in the temperature of the tool cutting edge has been devised for the purpose of suppressing a rapid increase in the tool wear rate. That is, as shown in the schematic view of FIG. 1, a temperature control system including a blade cooling system (Peltier element) and a system for controlling the blade temperature was devised. That is, a Peltier element capable of temperature control by voltage / current values was attached to the cutting edge rake face to prevent heat from being accumulated in the RcBN blank. Since the Peltier element has a cooling surface and a heat radiating surface, a heat sink was attached to the heat radiating surface to further enhance the cooling effect. Also, in order to avoid damage to the Peltier element and heat sink due to chips generated during turning and cutting, the heat sink should be of a type surrounding the Peltier element, and the protective plate made of cemented carbide at the contact area with chips. Pasted.

Then, the K-type thermocouple monitors the temperature at the end of the tool material during cutting and sends the temperature information to the H8 microcomputer via the thermocouple amplifier. In response to this, the H8 microcomputer transmits the temperature information to the computer PC, monitors the terminal temperature and the temperature rise rate, and the temperature measured by the K-type thermocouple is set to the target temperature set value (for example, 373K (R
The time for applying the voltage to the Peltier element is controlled by the pulse width modulation method so that the cutting edge temperature of the cBN tool material reaches a deterioration temperature of 1620 K))) or less.

As a result, the temperature of the RcBN tool was lowered, the wear rate of the tool due to the temperature rise could be prevented from increasing, and the life of the tool could be extended. As a result, it was possible to reduce the number of times of tool replacement, and there was no problem even if the continuous processing time was lengthened, and it was possible to improve the processing efficiency.

In the present invention, the binderless cBN (Rc
It is particularly effective when a tool made of a material having high thermal conductivity such as BN) or a diamond tool is used.

BEST MODE FOR CARRYING OUT THE INVENTION A machining apparatus according to the present invention comprises a tool holder, a tool held by the tool holder, and a Peltier element provided so as to abut the tool. In particular, it is provided with a tool holder, a tool held by the tool holder, a Peltier element provided so as to contact the tool, and a heat sink provided on a heat dissipation surface of the Peltier element.

A machining method according to the present invention comprises a tool holder,
A processing method using a processing device including a tool held by the tool holder, a Peltier element provided so as to contact the tool, and a heat sink provided on a heat radiation surface of the Peltier element in some cases. Therefore, it is a processing method in which a voltage is applied to the Peltier element at the time of processing to cool the tip of the tool.

A tool life extension method according to the present invention is a tool holder, a tool held by the tool holder, a Peltier element provided so as to abut against the tool, and a heat radiation surface of the Peltier element in some cases. A tool life extension method in which a voltage is applied to a Peltier element at the time of working to cool the tool tip portion, which is a working method using a working apparatus including a heat sink provided in the. The details will be described below.

FIG. 1 is an overall schematic view of a processing apparatus according to the present invention, FIG. 2 is a schematic view of a tool cooling portion of the processing apparatus of the present invention as seen from a lateral flank, and FIG. 3 is a tool of the processing apparatus of the present invention. It is a schematic diagram when a cooling part is seen from a front flank.

As can be seen from FIGS. 1 to 3, the tool holder 1
The RcBN tool 2 is held by. A Peltier element (maximum heat absorption amount is 4.5 W) 3 is provided so as to come into contact with the RcBN tool 2.

A heat sink 4 made of copper is provided on the heat radiation surface of the Peltier element 3. Further, in order to protect the Peltier element 3 from chips generated by processing, a cemented carbide plate 5 is provided at a contact portion with the chips.

The processing apparatus configured as described above (the tool is made of RcBN and the shape is (-5, -5, 5, 5, 15, 1)
5, 0.8), the cutting edge is provided with a negative land of 30 ° x 0.2 mm, and the cutting edge is a 0.02 mm round honing)
By using C = 3.31% by mass, Si = 1.86% by mass, Mn = 0.54% by mass, S = 0.10% by mass, Al
= 0.010 mass%, Cr = 0.036 mass%, Fe =
F of pearlite with Brinell hardness of 187
C300 material is a work material (outer diameter 160 mm, inner diameter 90 mm,
It was processed as a solid round bar having a length of 15 mm). Cutting conditions are cutting speed: V = 33.33 m / s, 41.67 m / s,
50.00 m / s and feed: f is 0.1 mm / re
v, cut: t was 0.5 mm. A two-color radiation thermometer was used to measure the cutting temperature.

When the RcBN tool is cut as described above, when no action is taken on the RcBN tool (dry type), when the RcBN tool is cooled by a coolant (coolant), cold air is blown on the RcBN tool. When sprayed (cold air), R
The relationship between the lateral flank wear width and the cutting distance was examined in each case where the cBN tool was cooled by the Peltier element (Peltier element). The results are shown in FIG. According to this, it is understood that the present invention using the Peltier device is excellent. For example, it is most effective in suppressing lateral flank wear. In addition, the temperature control can be performed more finely and the device itself is smaller and lighter than other methods.

In the case of the present invention and the case of the dry type,
The end temperature of the tool and the wear rate were examined, and the results are shown in FIGS. 5 and 6. According to this, when nothing is done, the temperature rises as the processing time elapses, but in the case of the present invention, the temperature is saturated at about 365K. The wear rate is about 1/50
You can also see that it has fallen to.

Further, in the case where the above cutting work of the present invention was carried out, elemental analysis of the tool edge portion (wear portion) was carried out, and the results are shown in FIG. The results of this elemental analysis were comparable to those performed with the RcBN tool under low velocity conditions. Therefore, it is understood that the present invention can obtain a long life equivalent to that when cutting is performed at a low speed even when the cutting is performed under a high speed condition exceeding 40 m / s.

In the above embodiment, the tool is R
Although it was made of cBN, the same applies to diamond tools.

The wear rate of the tool can be reduced, the life of the tool can be extended, the number of times of tool replacement can be reduced, and the working efficiency can be improved.

[Brief description of drawings]

FIG. 1 is an overall schematic view of a processing apparatus according to the present invention.

FIG. 2 is a schematic view of the tool cooling part of the processing apparatus according to the present invention as viewed from the side flank.

FIG. 3 is a schematic view of the tool cooling part of the processing apparatus according to the present invention when viewed from the front flank.

FIG. 4 is a graph showing a relationship between a lateral flank wear width and a cutting distance.

FIG. 5 is a graph showing the end temperature of the tool.

FIG. 6 is a bar graph showing the wear rate of tools

[Fig. 7] Element analysis chart of tool wear part

[Explanation of symbols]

1 Tool holder 2 RcBN tool 3 Peltier element 4 heat sink 5 Carbide plate (protection plate)

Claims (4)

[Claims] 1. A processing apparatus comprising: a tool holder, a tool held by the tool holder, and a Peltier element provided so as to abut the tool. 2. A tool holder, a tool held by the tool holder, a Peltier element provided so as to abut the tool, and a heat sink provided on a heat dissipation surface of the Peltier element. Characteristic processing equipment. 3. A machining method using the machining apparatus according to claim 1 or 2, wherein a voltage is applied to the Peltier element to cool the tip of the tool during machining. 4. A tool life extension method for extending the tool life during machining using the machining apparatus according to claim 1 or 2, wherein a voltage is applied to the Peltier element to cool the tip of the tool during machining. A tool life prolonging method characterized by: