JPS5939241B2 - Polygon processing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a polygonal machining method for cutting a workpiece into a polygonal shape.

Conventionally, the polygon machining method involves rotating both the workpiece 1 and the cutter 2 to cut a polygon.
A method was adopted in which polygonal machining was performed by changing the rotation ratio of the cutter 2 and the number of cutting edges of the cutter 2.

It was considered advantageous to make the cutter radius R' as large as possible in order to make the cut surface of the workpiece 1 as close to a flat surface as possible.

As a result, the workpiece 1 becomes a polygon, but due to variations in the cutter, each surface does not become an accurate plane at an accurate position, and therefore a regular polygon cannot be cut.

The present invention has been made to eliminate such drawbacks.

One embodiment of the present invention will be explained with reference to FIGS. 1 and 2. Numerals 3 and 4 are gears that determine the rotation ratio of the workpiece 1 and the cutter 2, and are fixed to the rotation shafts 8 and 9 of the spindles 6 and 7, respectively. ing.

Reference numeral 5 denotes an idle gear, which determines the rotation direction of the workpiece 1 and the cutter 2 and at the same time transmits the rotation of the gears 3 and 4.

In the above configuration, in order to cut the workpiece 1 into an accurate polygon, the number of cutting blades of the cutter 2 is one.

Generally, when the cutter has one cutting edge, the rotation ratio is the same as the number of corners of the polygon to be cut.

In the present invention, the value of R/R' is determined by the relationship between the number of corners N of the polygon to be cut, the distance R from the center of the workpiece 1 to each finished surface, and the cutter radius R' of the cutter 2. Since it is necessary to select a close rotation ratio K, the following equations (1) and (2)
Find the value of K from the formula.

However, N is the number of corners of the polygon to be cut, X is an integer such that the least common multiple of N and X is NXx. .

Next, the cutter radius is adjusted using the following equation (3) using the value of k determined above.

For example, when cutting a pentagon, R = 70
mm, I ('= 75 fi, R/R'=
70/75=0.933, and from equation (2), key 2
It becomes 4.

Substitute the above value into equation (1) to find the value of X.

X2N/ = 50/2.4 = 20.8 → 21 Therefore, k
250/21 kinaru.

Next ζ Substituting = 50/21 into equation (3) t gives R/
R'=0.907 and R'=77.2 rran.

In addition, when synchronous rotation transmission is performed using gears, R/R
The tooth number ratio of the gears 3 and 4 is adjusted according to the value of ', and the cutter radius R' is adjusted according to the tooth number ratio.

At this time, the value of k in the above equation (3) can be set to f = k = z / Z' above the number of teeth zL of gear 3 and the number Z' of teeth of both gears.

Furthermore, the distance from the center of the polygon you want to cut to each surface is R1 The distance from the center of the cutter to the tip of the cutting blade (cutter radius) is R
', then the ratio of the number of teeth of gear 3.4 is adjusted according to the value of R/R'.

Next, the cutter radius R is adjusted according to the tooth number ratio.

The above is performed based on the relationship 4) between R/R' and the rotation ratio.

Here, Z is the number of teeth of the gear 3, and l is the number of teeth of the gear 4.

The reason why the flatness of the sides of the polygon is improved by setting R/R'kik(k-2) will be explained with reference to FIG.

In Fig. 4, when the X-Y coordinate fixed on the cutting surface of the workpiece becomes X-Y' after t seconds, if the y-coordinate of the tip of the cutter blade is always zero until it leaves the workpiece, cutting The surface can be said to be a perfect plane.

From FIG. 4, the following equation (6) can be derived.

Here, if the number of angles of the polygon is sufficiently large and is selected to be ≦5, in practical terms Co5wt can be set as a close value, and C
oswt-::1- (wt)2/2--...
(8) can be used, Co5(k-1)wt becomes, and by substituting this into equation (7), we get The sides can be processed into flat surfaces.

According to such a method, the locus of the tip of the cutting edge of the cutter 2 relative to the workpiece 1 can be made to have an accurate plane so that it approaches a plane to a sufficient degree for practical purposes without increasing R′ forcibly. Can be cut into polygons.

In addition, because the cutter has one cutting edge, it is less necessary to align the cutter radius R' than when there are multiple cutting edges, and it is possible to reduce errors in R of each finished surface due to variations in the cutter radius R of each cutting edge. You can do amazing things without it.

In the above description, synchronous rotation transmission in which the rotation ratio between the workpiece 1 and the cutter 2 is determined by the gears 3 and 4 has been explained, but timing transmission by a timing belt and a timing pulley may also be used.

Alternatively, the rotating shafts 8 and 9 may be driven independently and synchronously rotated by a DC servo motor or a pulse motor.

Another embodiment of the present invention will be described with reference to FIG.
are fixed at equally divided positions on the outer periphery of.

In the above configuration, when the polygonal machining of the present invention is performed, the workpiece 11 can be cut into an accurate plane.

According to such a method, it is possible to perform high-quality flat surface machining with high cutting speed and high productivity.

As described above, according to the present invention, by simultaneously adjusting the rotation ratio of the workpiece and the cutter and adjusting the cutter radius, it is possible to obtain more accurate polygons and planes than ever before.

The present invention is a method that can be applied to polygon mirrors, multifaceted cutting of jewelry, flat cutting of abbreviations for watch dials, etc.

[Brief explanation of the drawing]

Fig. 1 is a mechanical diagram of the main parts of a polygon processing machine to explain the present invention, and Fig. 2 is a diagram of the positional relationship between the workpiece and cutter, taking an octagonal workpiece as an example to explain the present invention. It is. Further, FIG. 3 is a diagram showing the positional relationship between the workpiece and the cutter in planar processing of a small workpiece for explaining another embodiment of the present invention. FIG. 4 is a relationship diagram between a workpiece and a cutter to explain that the sides of a polygon are cut into planes. 1...Workpiece, 2...Cutter, 3,
4, 5... Gear, 8, 9... Rotating shaft,
6, 7... spindle, 11... small piece workpiece, 12... holder.

Claims (1)

[Claims] 1 In a polygonal machining method in which both a workpiece and a cutter are rotated to cut the workpiece into a polygon, the number of corners of the polygon to be cut is N, and the least common multiple of N and X is NXx. A relational expression between the ratio of the ratio to an integer X, the distance R from the center of the workpiece to each finished surface, and the distance R' from the center of the cutter to the tip of the cutting edge (hereinafter referred to as cutter radius), K=
Select the rotation ratio K from N/x, R/R/R'-K (K-2), and adjust the cutter radius R' so that it becomes R/R'-K (K-2). A polygonal processing method characterized by