JPH11123644A - Glass cutting multistage type cam and glass working method using glass cutting multistage type cam - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately mold and chamfer a complicated cover glass external shape by allowing a certain specific single stage or a plurality of stages to form a copying cam having the plurality of stages used for glass cutting, to have a function or a correlation with the other stage existing on the same cam. SOLUTION: The number of stage cams is decided by copying after a shape of glass. It consists of fours stages of the upper inclined face stage 42, the outer peripheral stage, the lower inclined face stage 43 and the work pressing- down stage 44, but when considering that an under surface is a plane, it becomes three stages since the outer peripheral stage and the lower inclined face stage can be used in common. For convenience, given names of the respective stages are set as the first stage (the work pressing-down stage) 44, the second stage (the outer periphery molding and thread chamfering stage) 43 and the third stage (the oblique chamfering stage) 42 from the side close to a work 45. The first stage 44 is a similar figure to the second stage 43, and is smaller than the second stage 43, and similarity magnifying power is decided by considering pressure to press-down the work 45.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-stage glass cutting cam used for forming an outer periphery of an inorganic glass or sapphire glass used for a cover glass for a timepiece, and a glass processing method using the multi-stage cam for glass cutting. It is about. In particular, the present invention relates to a multi-stage glass cutting cam used for products having a complicated outer peripheral surface and a spherical surface or a curved surface, and a glass processing method using the multi-stage glass cutting cam.

[0002]

2. Description of the Related Art Conventionally, a single-stage cam has been used for forming an outer periphery of inorganic glass or sapphire glass used for a cover glass for a timepiece. The single-stage cam is a cam made for the purpose of molding only the outer peripheral shape of the watch cover glass, and has a structure having a step similar to the outer peripheral shape of the glass.

[0003]

However, a single-stage cam can only form the outer peripheral shape of a cover glass having a complicated shape, and when chamfering, after finishing the upper surface shape, the intersection of the upper surface and the outer peripheral shape is required. In order to follow
The chamfered shape was easily affected by the roughness of the intersection and the state of chipping. In addition, the number of steps was large because there was an independent chamfering step.

[0004]

SUMMARY OF THE INVENTION In order to solve the above-mentioned conventional problems, the present invention provides a copying cam having a plurality of steps used for cutting glass, wherein one or more specified steps are on the same cam. Has a function or a correlation with the other stages in the above. In addition, a cam having a plurality of steps used for cutting glass is formed, and two steps having a functional relationship or a correlation are adjacent to each other, and a portion where the two steps are straight lines corresponds to a portion where the copying wheel contacts. It has a configuration with one or more locations.

[0005] Further, using the multi-stage cam for glass cutting having the above-mentioned configuration, the upper and lower surfaces are chamfered in the same process at the same time when the shape such as the outer periphery of the glass is formed, and the width and continuity of the chamfer on the curve are obtained. This is a processing step in which cutting is performed with uniform properties.

[0006]

Embodiments of the present invention will be described below with reference to the drawings. In order to solve the above-mentioned problems, it is considered to be divided into three elements of a cam design, a cam production, and a step of using a cam. This will be described in 2. Since the manufacture of the cam is a usual metal working and surface treatment, no particular description is given. (1) Embodiment 1 FIG. 1 shows a design procedure of a multi-stage cam for glass processing according to the present invention. The cover glass for a watch shown here uses blue plate glass (common name of soda lime glass) 41 in inorganic glass as shown in FIG. 2 and its outer peripheral shape is constituted by a part of a plurality of circles, and the upper surface is spherical. The lower surface is a flat glass. A method of designing a multi-stage cam for processing the glass will be described.

A glass drawing describing the shape and dimensions of glass as shown in FIG. 2 is prepared (step 101). FIG.
FIG. 2A shows a front view of the glass, and FIG. 2B shows a side view of the glass. Next, the number of cam steps is determined according to the shape of the glass (step 102). Example 1
In this case, there are four steps: a step 42 for the upper slope, a step for the outer periphery, a step 43 for the lower slope (yarn surface), and a step 44 for the work holding.
Considering that the lower surface is a flat surface, the outer peripheral step and the lower slope step can be shared, so that there are three steps. Here, the upper slope refers to a chamfered surface on the outer periphery of the timepiece glass, which is located on the front side of the finished timepiece, and generally has a larger amount of chamfer than the lower slope and is often polished. In addition, in the case of a watch glass, in the case of a finished watch, the outer periphery means a chamfered surface of the outer periphery of the glass which comes inside the case. Further, the work holder has a purpose of holding the workpiece so as not to move as shown in FIG. 5 when cutting glass. Further, the work means an inorganic glass such as a blue plate glass or a white plate glass or a crystallized glass such as sapphire glass to be processed.

For the sake of convenience, the names of the stages are, for convenience, the first stage (work holding stage) 44 and the second stage (outer periphery forming and yarn chamfering) from the side closer to the work 45 in the construction diagram of the processing machine shown in FIG. Step) 4
3, the third step (beveling step) 42; First, in the basic step of designing the second step 43, since the plan view of the glass drawing shown in step 101 and the cam shape of the second step 43 are similar to each other, they are reduced to the actual dimensions specified in the glass drawing. (Step 103).

The first stage 44 has a similar shape to the second stage 43 and is smaller than the second stage 43, and determines the similarity magnification in consideration of the pressure for holding the work 45 (step 104). The work 4 is subjected to the stress applied to the work 45 from the cutting wheel 12 during machining.
5 requires a total pressure that does not cause displacement, so that the similarity magnification is preferably about 80% of the area 43 of the second stage 43.

Next, a method of designing the third stage 42 will be described. The plan view of the glass is a figure on the XY plane (Figure 1), which is in contact with two points corresponding to the major axis on the outer peripheral shape, and a given spherical ratio R
Is drawn on the XZ plane. This circle is represented by the following equation (1). Formula (1) Y ² + (Z−√ (R ² − (L / 2) ² )) ² = R ² where L = the major axis of glass.

Next, a sphere having a radius R including the circle 1 is assumed, and its equation (sphere 1) is obtained. The sphere 1 is represented by the following equation (2). Equation (2) X ² + Y ² + (Z−√ (R ² − (L / 2) ² )) ² = R ² Next, the XY coordinates of an arbitrary point N on the outer periphery of FIG.
The obtained XY coordinates are substituted into Equation 1 to obtain a Z-axis coordinate value (value N1). The value N1 is represented by the following equation (3).

Equation (3) N1 = √ (R ² −N _X ² −
N _Y ² ) + √ (R ² − (L / 2) ² )
A value (value N2) is calculated by multiplying the axis coordinate value by the slope angle count. The value N2 is represented by the following equation (4). Equation (4) N2 = k * N1 where k is a slope angle count, and k = 1 / COS
(Φ). φ is the slope angle.

The value N2 is a value indicating the machining height of the slope at the point N, that is, a value indicating the distance at which the grindstone separates from the work, but when reflected on the cam, the point M corresponding to the point N is XY coordinates of point M (value Mx, value My) because of the relationship of polar coordinates
Convert to The value Mx and the value My are represented by Expression (5) and Expression (6), respectively. Equation _{(5) M X = N X} + N2 * N Y / √ (N Y 2 + N X 2) Equation _{(6) M Y = N Y} + N2 * N X / √ (N Y 2 + N X 2) followed by the value N3 Is calculated for all points N on FIG. 1, and when all the points M are connected, the shape becomes the third stage (step 105).

Next, the shape of each step is processed using the NC processing machine 46 (step 106). The NC processing machine 46 is a processing device capable of specifying two-dimensional or three-dimensional coordinates and performing continuous processing while following the coordinates. At this time, the material of the cam is preferably SCM435 and SUS. Next, the surface of the cam is finished to a smooth surface with a file or a diamond buff 47 (step 107). The diamond buff is a facility for allowing a buff to contain a mixed solution of an oily solution and diamond particles for precision polishing.

Next, the entire surface of the cam is nitrided (step 108). This process reacts the metal surface with nitrogen,
A surface treatment method for forming a metal nitride film, which is used for protecting the surface and maintaining the surface hardness. The surface hardness at this time is preferably 600 in Vickers hardness. FIG. 3 shows a front view, a side view 1 and a side view 2 of the multi-stage cam formed by the above-described design procedure as viewed from a different direction from the side view 1 and the side view 1. (2) Second Embodiment FIG. 4 shows a process diagram for performing the outer periphery forming of glass using the multi-stage cam manufactured in the first embodiment, and FIG. 5 is a configuration diagram of a processing machine for performing the outer periphery forming of glass. is there. The processing machine is composed of a copying cam type automatic centering machine 50, a cutting wheel 51, a copying wheel 52, a work holding bracket 11, a multi-stage cam, and glass for work. As the cutting liquid, either oily or aqueous is used.

The automatic centering machine 50 includes a diamond wheel.
The multi-stage cam and the whirler are rotating while the cutting fluid is flowing.
The work 45 is set between the clamps 11 (step 201). When the work is started after the work 45 is set, the work shaft 52 starts rotating, the diamond wheel 51 gradually approaches the work, and approaches until the copying wheel 52 hits the multi-stage cam. (Step 202). Copying wheel 5
2 corresponds to the outer peripheral forming step, and the work 45 is subjected to the outer peripheral forming according to the shape of the outer peripheral forming step 43 (step 20).
3). FIG. 9A shows how the outer periphery is formed.

Next, the wheel shaft moves to the left with respect to the work shaft, and the copying wheel 52 is moved to the upper slope forming step 4 of the multi-stage cam.
Two hits. FIG. 9 (B) shows the state of this beveling. In this state, the upper slope is chamfered according to the shape of the upper slope forming step (step 204). Next, the wheel shaft moves to the right with respect to the work axis, and the copying wheel 52 is moved to the lower slope forming step 4.
Hit 3. This thread chamfering is shown in FIG. 9 (C). In this state, the lower slope is chamfered according to the shape of the lower slope forming step (step 205).

Thereafter, the wheel shaft separates from the work shaft,
The work shaft stops rotating, and one cycle of glass processing is completed (step 206).

[0019]

As described above, by using the multistage cam of the present invention, it is possible to accurately form and chamfer the outer shape of the cover glass having a complicated shape. Further, since the multi-stage cam can perform the outer peripheral grinding and the chamfering of the slope and the thread surface in the same process, it is not necessary to perform the machining of the slope and the thread surface in an independent process, which is caused by performing an independent process. This has the effect of suppressing an increase in processing cost and an increase in processing time.

[Brief description of the drawings]

FIG. 1 is a flowchart showing a procedure for designing a multi-stage cam.

FIG. 2 is a top view (FIG. 2A) and a side view (FIG. 2B) showing a glass shape.

FIG. 3 is a front view showing the shape of a multi-stage cam (FIG. 3)
(A)), a side view (FIG. 3B) and a side view (FIG.
(C)).

FIG. 4 is a flowchart showing glass processing steps using a multi-stage cam.

FIG. 5 is a configuration diagram showing a configuration of a glass processing machine.

FIG. 6 is a schematic view illustrating the operation of the glass processing machine.

[Description of Signs] 41 Blue sheet glass 42 Step for upper slope 43 Step for outer periphery / lower slope 44 Work holding step 45 Work 46 NC processing machine

Claims (3)

[Claims] 1. A copying cam having a plurality of steps used for cutting glass, wherein one or more specific ones of the plurality of steps have a function or a correlation with other steps on the same cam. Multistage cam for glass cutting characterized by the following. 2. A cam having a plurality of steps used for cutting glass, wherein, of the plurality of steps, two steps having a functional relationship or a correlation are adjacent to each other, and a portion where a scanning wheel contacts is located.
A multi-stage glass cutting cam characterized by having one or more portions where one step becomes straight. 3. A glass cutting multi-stage cam according to claim 1 or 2, wherein the upper and lower surfaces of the glass are chamfered in the same step at the same time as the shape of the outer periphery of the glass is formed. Glass processing method using a multistage cam for glass cutting.