JP2006263910A - Grinding tool and cavity grinding method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a grinding tool which can be simply manufactured in a time-saving manner, and a cavity grinding method. <P>SOLUTION: This grinding tool includes a main body 12. The grinding tool is preferably designed rotationally symmetric into a disc shape having a shaft for mounting the grinding tool 10 to a spindle. The main body 12 includes an outer tubular face 18, and a first front face 20 directed to a direction separated from the shaft 14. One part of the tubular face 18 and the first front face 20 is coarted with a grinding material, and the tubular face 18 includes a plurality of recesses 22 communicated with the first front face 20. The grinding tool 10 can be advantageously used for manufacturing a cavity with an undercut on a glass ceramic or ceramic workpiece. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

The present invention relates to a grinding tool comprising a body having a shaft for mounting a grinding tool on a spindle, the body preferably designed in a rotationally symmetric plate shape. The main body includes an outer side surface and a first end surface opposite to the shaft, and a polishing layer is provided on the side surface and a part of the first end surface.
The invention further provides for grinding cavities, preferably undercut cavities, preferably into glass, glass ceramic or ceramic workpieces, in particular lightweight glass ceramic structures, for example made by Zerodur®. The present invention relates to a grinding method for manufacturing.

  The above-mentioned type of grinding tool is well known in the abstract of the following patent document 1. This known grinding tool is configured in a pot shape, and a plurality of supply channels extending obliquely inside the cavity are provided on the inclined rear surface of the pot. The cavity communicates with the end face of the pot-shaped body through a number of channels, and the channel opens into the end face, thereby allowing the pot to pass through the inclined channel on the side of the grinding tool opposite to the end face. A discharge opening is formed for the gas or grinding fluid supplied into the cavity surrounded by the shaped body.

This type of grinding tool is particularly well suited for surface grinding or hollow hole grinding. Undercut cavities cannot be ground with this type of grinding tool.
Especially when grinding large components made of glass, glass ceramics or ceramics, such as Zerodur®, the purpose is often to produce lightweight structures and reduce the weight of such structures themselves. There is. This type of lightweight structure made of a material known as Zerodur® is used, for example, in the manufacture of reflectors in the astronomical field. In this case, the workpiece is provided with a plurality of undercut cavities on the rear surface facing away from the reflecting mirror surface, thereby maintaining the reflecting mirror body in a very stable shape. It has been done to reduce its own weight.
JP 05-069339 A

  The object of the invention is here to be able to produce cavities, in particular holes with undercuts of the type required for the production of lightweight structures made of Zerodur®, in a particularly simple and time-saving manner. A grinding tool and a cavity grinding method are provided.

This object is achieved by a grinding tool of the above type provided with a plurality of recesses opened in the first end face on the side surface.
Thus, the object of the present invention is completely achieved.
The concave portion provided on the side surface and opened to the first end surface discharges the grinding substance (the material scraped off) and the grinding liquid from the first end surface in a direction away from the processing position particularly efficiently through the concave portion. to be certain.

  This makes it possible to process a large polishing volume without having to lift the grinding tool out of the drill hole so that the grinding material can be carried out. Alternatively, the grinding tool can be cut directly into the solid block and used to form a relatively deep hole. Once the hole has reached a sufficient depth, the grinding tool can be moved laterally and its sides can be used to gradually widen the hole laterally to create an undercut cavity. These recesses on the side then act on the one hand to facilitate lateral movement and on the other hand also carry out the grinding substance.

In another embodiment of the present invention, the main body includes an axial second end surface in which a concave portion on the side surface is opened.
This ensures that the grinding material is efficiently transported even when the axial end face of the grinding tool is used to grind the inner surface of the undercut.
In a further development of the invention, the recess is configured as an inclined groove on the side opening to the recess on at least one end face.

In yet another configuration of the present invention, the body is configured in a plate shape, and the recess includes a groove that extends radially at the first end face and communicates with the inclined recess at the side. .
This arrangement ensures that the grinding material is particularly preferably removed from the central region of the grinding tool to its edge and then through its side to the rear.

In yet another embodiment of the invention, the radially extending recess opens into the central recess.
This arrangement also improves the removal of the grinding material from the grinding position.
In yet another development of the invention, a fan-shaped recess is provided on the first end face.
In yet another development of this embodiment, at least some of the fan-shaped recesses communicate with the radially extending recesses via connecting channels extending in the circumferential direction.

As a result, it is ensured on the one hand that the grinding effect is improved with respect to the first end face and on the other hand the removal of the grinding substance is also improved at the same time.
In another embodiment of the present invention, each of the plurality of recesses, preferably 6 recesses, communicates with the radially extending recesses of the first end face and has a constant (regular) angular spacing on the side. Is provided.

In another development of this embodiment, the side recess opens into a circular annular recess in the second end face.
Due to this feature, particularly when the portion remaining in the flange shape is ground from the inside by the second end face, the removal of the grinding substance and the improvement of the supply amount are surely made.
According to a further advantageous development of the invention, the side recess preferably extends at an acute angle with respect to the first end face, preferably in the range of 10 ° to 60 °, more preferably in the range of 20 ° to 40 °.

It has been found that a particularly good feed rate and a particularly efficient removal of the grinding substance can be achieved with such a side recess configuration.
The grinding layer of the grinding tool is preferably configured as a diamond layer.
This is particularly advantageous when processing glass, glass ceramic or ceramic materials.

In the grinding method according to the present invention, the grinding tool according to the present invention is used for grinding a solid block to form a cavity therein. Moving the grinding tool laterally can provide an advantageous method of producing a uniform cavity with an undercut.
The grinding tool is preferably driven in a rotational direction such that the inclined concave portion on the side surface of the grinding tool extends from the second end surface to the first end surface.

As a result, the grinding substance can be removed particularly efficiently from the machining position.
The above features of the present invention and the features described below can be used not only in the respective combinations specified, but also in other combinations or alone, without departing from the scope of the present invention. It will be understood.
Further features and advantages of the present invention will become apparent from the following description of preferred embodiments of the invention with reference to the drawings.

The grinding tool of the present invention is shown in FIGS. 1 and 2 and is generally designated by the reference numeral 10.
The grinding tool 10 includes a shaft 14, which is used to mount the tool on the grinding spindle, and a plate-like body 12 is fastened to the shaft 14 by, for example, a welding line 38 (FIG. 2). reference). The main body 12 includes a first end surface 20 on the side away from the shaft 14 and a second end surface 34 on the side facing the shaft 14. The cylindrical side surface 18 extends between these two end surfaces 20, 34.

  Groove-shaped six inclined recesses 22 are provided in the side surface 18 at regular (regular) angular intervals, and these inclined recesses 22 open into the radially extending recesses 24 of the first end face 20. ing. Further, similarly, the recess 22 opens into a circular recess 36 of the second end surface 34. An acute angle of about 30 ° is formed between the recess 22 and each of the first end surface 20 and the second end surface 34. The radially extending recess 24 of the first end face 20 is formed as a groove that opens in the central circular recess 32 of the first end face 20.

  In addition, a total of six fan-shaped recesses 26 are provided in the first end face 20, each fan-shaped recess 26 communicating with the associated radial recess 24 via a connecting channel 28 extending in the circumferential direction. is doing. These radial recesses 24 are delimited by a central circular region 30 on the side facing the central recess 32 and are also spaced from their associated radial recesses 24 by arcuate raised flanges 28 as well. .

Except for the central circular region 30, all the raised portions of the first end face 20 are provided with a diamond grinding layer. The diamond grinding layer is further extended to the entire side face 18 and the raised portion of the second end face 34.
Thus, the raised portion of the first end face 20 acts as a grinding surface, which makes it possible to efficiently remove grinding material when grinding the interior of a solid block, for example, to form a hole. The fan-shaped recess 26 acts on the one hand to form a grinding edge in the nearby flange, and on the other hand via the connecting channel 28 and the radial recess 24 and finally in communication with the radial recess 24 and the side surface 18. It acts so that the grinding substance is carried out to the rear part of the grinding tool 10 via the inclined recess 22.

  Once the cavity is formed on the workpiece surface by grinding, the undercut cavity can be gradually formed by the corresponding lateral movement of the grinding tool. During the processing, even when processing at the second end face 34, the recess 36 of the second end face 34 receives the grinding material and, on the other hand, through the inclined recess 22 of the side face 18 It is still possible to remove it.

The rotation direction (counterclockwise direction) of the grinding tool 10 is indicated by an arrow 17 in FIG. The rotational direction 17 is preferably selected such that the recess 22 of the side surface 18 extends from the second end surface 34 toward the first end surface 20.
Thereby, it is possible to reliably remove the grinding substance from the processing position on the first end face 20.

  FIG. 3 is a schematic view of a lightweight structure made of Zerodur® (a lithium aluminosilicate glass ceramic with almost zero thermal expansion, commercially available from Schott Aktiengesellschaft), indicated generally by the reference numeral 40. It is. Using the grinding tool of the present invention, a plurality of cavities having a honeycomb structure are formed inside the lightweight structure of the workpiece 40. Each cavity 42 includes a central circular opening 44 below which the cavity 42 extends laterally, thereby forming an undercut cavity 42. As schematically shown in FIG. 3, the outer contour of the cavity 42 is generally hexagonal with rounded side edges, the rounded radius being predetermined by the outer periphery of the grinding tool used.

  FIG. 4 schematically illustrates how such a lightweight structure 40 can be formed using the grinding tool 10 of the present invention. First, using the grinding tool 10 of the present invention, the solid block is ground to form a cavity therein until the depth of the cavity 42 reaches a desired value. Next, the hexagonal cavity 42 can be gradually formed by moving the grinding tool 10 in the lateral direction. The cavity 42 is in a state of being separated from the outer surface 48 of the workpiece 40 by the portion remaining as the flange 46.

The first position of the grinding tool 10 is shown on the left side of FIG. In the center region of FIG. 4, a grinding tool indicated by 10 'in the grinding process of the inner surface of the portion remaining as the flange 46 in the formed undercut region is shown. The right side of FIG. 4 shows the process of grinding the bottom of the cavity 42 using the grinding tool 10 ".
The continuous outer surface 50 opposite the surface 48 can be used, for example, in the manufacture of mirror surfaces, for example in the manufacture of astronomical reflectors.

1 is a perspective view of a grinding tool of the present invention, and particularly shows a first end face and a side face opposite to an axis. It is the perspective view seen diagonally from the rear part of the grinding tool of Drawing 1, and is in the state where the side and the 2nd end face of the rear part are visible (a little enlarged compared with Drawing 1). It is a top view of the workpiece for manufacturing the lightweight structure in which the several cavity with an undercut was formed. FIG. 4 is a cross-sectional view of the workpiece of FIG. 3, showing cavities at different stages of the grinding process side by side with the grinding tool of the present invention.

Claims (13)

A main body (12) having a shaft (14) for mounting a grinding tool (10) on a spindle is provided, and this main body (12) is preferably configured in the shape of a rotationally symmetric plate, the main body (12) being An outer side surface (18) and a first end surface (20) opposite to the shaft (14), wherein the outer side surface (18) and a portion of the first end surface (20) comprise a polishing layer;
The grinding tool according to claim 1, wherein the outer side surface (18) includes a plurality of recesses (22) opened in the first end surface (20).   The grinding tool according to claim 1, wherein the main body (12) includes a second end surface (34) in which the concave portion (22) of the outer side surface (18) opens on the shaft (14) side. .   The recess (22) is formed as an inclined groove on the outer side surface (18) that opens into the recess (24, 36) in at least one of the end faces (20, 34). The grinding tool according to claim 1 or 2.   The body (12) is formed in a plate shape, and the recess (24) extends radially at the first end surface (20) and the inclined recess (22) of the side surface (18). The grinding tool according to claim 3, further comprising a groove that communicates with the grinding tool.   5. A grinding tool according to claim 4, wherein the radially extending recesses (24) open into the central recess (32).   The grinding tool according to claim 4 or 5, wherein the first end face (20) is provided with a circular fan-shaped recess (26).   At least some of the circular sector recesses (26) are in communication with the radially extending recesses (24) via connection channels (28) extending in the circumferential direction. Item 7. The grinding tool according to Item 6.   A plurality of, preferably six, recesses (22) are provided in the side surface (18) at regular angular intervals, and each of the recesses (22) is in the first end surface (20). The grinding tool according to claim 1, wherein the grinding tool communicates with the radially extending recesses (24).   A plurality of recesses (22) opening into a circular annular recess (36) in the second end surface (34) are provided on the side surface (18) at a constant angular interval. Item 10. A grinding tool according to any one of Items 1 to 8.   The concave portion (22) of the side surface (18) extends with an acute angle, preferably in the range of 10 ° to 60 °, more preferably in the range of 20 ° to 40 °, with respect to the first end surface (20). The grinding tool according to any one of claims 1 to 9.   The grinding tool according to claim 1, wherein the polishing layer is formed as a diamond layer. In order to produce a particularly lightweight glass-ceramic structure, a cavity (42), preferably a cavity with an undercut (46), is formed by grinding inside the workpiece (40) made of glass, glass ceramics or ceramics. A way to
A grinding method including a step of grinding a workpiece with the grinding tool according to claim 1.   The grinding tool is driven in a rotational direction (17) such that the inclined recess (22) of the side surface (18) extends from the second end surface (34) to the first end surface (20). The method according to claim 12, characterized in that:

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