Machining apparatus

Abstract

A machining apparatus for conducting at least one of a cutting process and a grinding process, comprises a stationary base; and a working device mounted on the stationary base and having a degree of freedom of more than two axes to conduct at least one of a cutting process and a grinding process, the working device comprising a first working bench which is formed of a ceramic material and is movable linearly with a degree of freedom of not less than one axes or more while holding a work piece or a tool.

Description

BACKGROUND OF THE INVENTION [0001] This invention relates to a machining apparatus having a degree of freedom of machining of three axes or greater. [0002] Herein, the term “axes” or “an axis” is defined as a portion of a machining apparatus that functions as the reference line or plane of a movement for machining, for example, the rotary shaft of a swivel table, the slideway of a slide table, etc. The degree of freedom of movement for machining is one for each of the “axes”. [0003] A machining apparatus for applying cutting machining, grinding machining, or the like to an optical element and a die for the formation thereof is known (refer to the patent literature 1). [0004] [Patent literature 1] The publication of the unexamined patent application 2003-39294. [0005] In this connection, in order to generate a complex curved surface corresponding to an aspherical surface of an optical element with a high accuracy, a degree of freedom of machining of two or less is insufficient, and a...

AI Technical Summary

Benefits of technology

[0016] Further, in a machining apparatus having a degree of freedom of machining of three axes or greater, it is carried out in most cases, a shaping machining, that is, a machining in which, in association with a reciprocating movement with respect to one axis, another movement with respect to another axis is carried out, which moves a tool along the cross-sectional shape of a free surface, and by the three-dimensional accumulation of a number of movements of the tool one above another, a curved surface is generated by cutting, grinding, etc.; however, this shaping machining takes a very long time, particularly, in generating a high-accuracy optical surface, even for a work piece of a size of an order of several centimeters, it is general that a machining time of several ten hours is required for it. Accordingly, it is very important for the purpose of carrying out a high-accuracy generating of an optical surface, how to make the machining difficult to undergo the influence of the change of the environment such as the temperature during the period of time of machining, or to make the variation of the environment during the machining smaller by shortening the machining time.

[0019] In contrast with this, according to this invention, by forming the above-mentioned first workbench of a ceramic material, in comparison, for example, with a conventional workbench made of cast iron, its weight can be reduced by a large margin and its Young's modulus can be made two times larger; therefore, bending caused by the self-weight can be suppressed, and it is obtained a structure such that a resonance or the like is hard to produce because the specific frequency of the vibration is made higher.

Problems solved by technology

Therefore, because the workbench becomes heavy, and the power of a servomotor required for driving this becomes high, there has been a problem that the quantity of heat generation from this motor becomes large.

Further, because it has not been possible to move the workbench at a high speed, there has been also a problem that the speed of machining becomes slow, which makes the machining time longer, and if a variation of the environment such as the temperature occurs, the deformation of the workbench due to thermal expansion and the drift of position of a work piece and a tool become large, which makes a high-accuracy machining difficult.

; however, this shaping machining takes a very long time, particularly, in generating a high-accuracy optical surface, even for a work piece of a size of an order of several centimeters, it is general that a machining time of several ten hours is required for it.

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