JPS6317582B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a stylus for a profile cutting device.

Conventionally, surface contour cutting and contour contour cutting are known as contour cutting methods, and only one of them is applied depending on the workpiece. In surface profiling cutting, the stylus is tilted on the ascending slope of the model in the forward pass, and the greater the inclination of the slope, the more the blade is in front of the stylus, so the depth of cut of the blade is large and over-shaving occurs, and on the return trip, When the model descends on the ascending slope, the stylus goes ahead of the cutter, and the depth of cut of the cutter becomes smaller, resulting in an uncut phenomenon. Therefore, if the surface is steeply sloped, the finished surface of the workpiece will be rough, and manual finishing will be required as a post-process, resulting in a very time-consuming process.

Surface contour cutting also has the following drawbacks. That is, in order to reciprocate and trace the surface of the mold surface, up-cutting and down-cutting are repeated, and cutting conditions must therefore be set to up-cutting, which has lower cutting performance. Moreover, when the stylus reaches a surface close to the horizontal surface of the model surface to a surface close to the vertical surface, the side of the end mill hits the machined surface of the workpiece at the same time, resulting in an excessive load on the end mill.
The end mill may be damaged. In order to solve this problem, after cutting all the model surfaces along the contours, tape or the like is pasted on the steep slopes of the model in advance to prevent the stylus from tracing the steep slopes before cutting the contours. must be done. However, in the case of models with complex shapes, this method requires a very complicated and time-consuming task of applying tape only to steep slopes, making it impractical.

In addition, in contour cutting, cutting can be done with highly efficient downcuts, so excellent surface roughness can be obtained on steeply sloped surfaces. However, since the pick feed is performed in the vertical direction while cutting along the contour on the contour line, the intervals between the cutting paths become wider on surfaces close to the horizontal surface of the model surface, resulting in a rough machined surface, and manual finishing is required as a post-process. Become. In this case, the pick feed can be set small so that the path interval is sufficiently small even on slopes that are close to the horizontal surface, but in that case, the pick feed is too small on steep slopes and only a small amount of machining is performed, resulting in very low machining efficiency. The disadvantage is that it becomes worse.

The present invention was made in order to eliminate such conventional drawbacks, and provides a stylus that does not require manual finishing and can perform precise finishing cutting only by profile cutting.

That is, the present invention is a stylus for surface tracing of a tracing cutting device in which an end mill corresponding to the stylus cuts a workpiece according to the contour, and has a cylindrical shaft portion and a head formed at the tip thereof,
The head is formed in the same shape as the head of the corresponding end mill, and the shaft is formed sufficiently larger than the outer diameter of the end mill. In contrast, the lower end of the shaft is formed so that only the head comes into contact with it. If you perform surface profile cutting using a stylus with this shape, the end mill will not cut on steep slopes, which will prevent damage to the end mill, and will also avoid the complicated process of pasting tape, etc. on the steep slopes of the model. Work can be omitted. Cutting of gentle slopes can be performed separately using a regular stylus by contour cutting. Here, the gentle slope refers to a slope closer to a horizontal plane than the slope where the lower end and head of the shaft of the stylus of the present application are in contact with at the same time, and the steep slope refers to a slope closer to a vertical plane. The boundary between a steep slope and a gentle slope is the boundary between surface cutting and contour cutting, and this angle may be set within a range of 45°±15° from the horizontal plane. This is because if the range is exceeded, respective drawbacks will occur.

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a schematic diagram of a milling machine used to carry out the present invention, where B is a bed, H is a spindle head, E is a ball end mill, T is a tracer, S is a stylus, W is a workpiece, and M is a model. As shown in FIG. 2, the end mill E has a hemispherical head _E1 with a radius of curvature R at the tip of a cylindrical shaft.

The corresponding surface profile (X-Z axis, Y-Z axis
As shown in FIG. 3, the stylus for the cylindrical shaft 13 has a head formed at the tip thereof, and this head forms part of a hemispherical surface having the same shape as the head of the end mill E. It consists of a head 11, and the head 11 and the shaft portion 13 are continuous through a conical surface 12. The radius of curvature of the head 11 is set to R+x, and the head 11 is made larger than the head of the end mill by a small amount of tilt correction amount x, but this is to absorb the tilt of the stylus on the inclined surface. and
This degree of difference from the end mill head is within the same range in this specification.

The conical surface 12 has a cross section including the rotation axis _N1 ,
The stylus S 1 is formed on a tangent to the outer circumferential end of the head 11 and continues to the shaft 13 , and therefore the diameter of the shaft of the stylus S ₁ is sufficiently larger than the diameter of the end mill. Although the inclination of this tangent line is set at 45° with respect to the horizontal plane in the illustrated example, this angle may be appropriately selected within the range of 45°±15°. Here, "sufficiently large" means a degree to which the corresponding end mill will not cut the workpiece when the lower end of the shaft portion 13 of the stylus comes into contact with the model surface. The stylus S ₂ for contour tracing has the same shape as the end mill E consisting of a shaft portion 22 and a hemispherical head 21 (however, the radius of curvature of the head is R+x) as shown in FIG.

The stylus may also be constructed as shown in FIG. That is, the stylus S ₃ consists of a cylindrical shaft portion 13 and a head having a flat portion 10 at the tip and a curved surface 15 around it, and the curved surface 15 and the shaft portion 13 are continuous at the conical surface 12 . When using this stylus, the corresponding end mill E ₃ should also have a head having a flat part 10 and a curved surface 15 of the same shape, and a shaft part formed thinner than the shaft part 13 of the stylus S ₃ . use

Next, a profile cutting operation using the above-mentioned styluses _S1 and _S2 will be explained. First, using the surface tracing stylus S ₁ , as shown in Figure 6,
The stylus is reciprocated in the X-axis direction while the pick is fed in the Y-axis direction and reversed to perform surface contour cutting. At this time, as shown in FIG. 7, the head 11 of the stylus S ₁ comes into contact with the model M on a surface close to the horizontal surface, and the workpiece W is cut in the shape of the model M. Slanted surface 4 with an angle of inclination of 40° from the horizontal plane
0 as well, the head 11 contacts and cuts the workpiece W. When reaching the inclined surface 60 with an inclination angle of 60°,
Since the lower end of the shaft portion 13 comes into contact, the head 11 separates from the surface of the model M, and therefore the end mill E also separates from the workpiece W and does not perform cutting. Similarly, on the inclined surface 80 with an inclination angle of 80°, the head 11
is away from the surface of model M and is not cut by the end mill. When the stylus S ₁ reaches the inclined surface 20 having an inclination angle of 20°, the head 11 comes into contact with it again and cutting by the end mill E is performed. That is, since the tangential line of the stylus S ₁ to the head 11 is continuous with the conical surface 12 at a position of 45 degrees, the head 11 is connected to the conical surface 12 when the slope of the model is less than 45 degrees (gentle slope). The lower end of the shaft portion 13 comes into contact with the model M to cause the end mill E to cut the workpiece, and on slopes of 45° or more (steep slopes), the lower end of the shaft portion 13 comes into contact with the model M and does not cut the workpiece. Therefore, by surface contour cutting, gentle slopes can be cut with high precision, and damage to the end mill can be prevented without having to perform the complicated work of applying tape or the like to steep slopes.

The workpiece W on which the steep slope has not been cut is then cut by using a stylus _S2 having the same shape as the end mill E to trace the contour of the model M as shown in FIG. In this case, the end mill E contacts all surfaces of the workpiece W, but the gentle slopes are not cut because they have already been cut along the surface, but only the steep slopes are cut. Therefore, the problem of pitch roughness on gentle slopes does not occur.

Note that, contrary to the above, surface tracing cutting may be performed after contour tracing. In this case, the steep slope is completely cut while contour cutting, and the gentle slope is roughly cut, and then the gentle slope is completely cut by surface contour cutting. In this case as well, there is an advantage of using the stylus _S1 . In other words, errors tend to occur in the amount of movement in the horizontal direction when contour tracing is performed, and if surface tracing cutting is performed using a conventional stylus after contour tracing cutting, there is a risk of cutting into the steep slope that has been cut. Using the stylus S ₁ can definitely prevent this.

As explained above, this invention has a structure that allows the stylus for surface tracing to cut only gentle slopes, and if a milling machine is used to perform normal surface contour cutting, steep slopes will not be cut automatically. Since the end mill is moved in this manner, there is no need for complicated work to prevent breakage of the end mill as in the conventional method, and work efficiency can therefore be significantly improved.

[Brief explanation of the drawing]

Fig. 1 is a schematic explanatory diagram of a milling machine implementing the present invention, Fig. 2 is a side view of a corresponding end mill, and Fig. 3 is a side view of a corresponding end mill.
FIG. 4 is a side view of a stylus for contour tracing; FIG. 5 is a side view of another embodiment of the invention; FIG. 6 is a diagram illustrating cutting work; FIG. 7 is an enlarged explanatory view of the stylus tracing the workpiece. S ₁ , S ₂ ...Stylus, 11...Head, 13...Shaft, E...End mill, M...Model, W...Workpiece.

Claims (1)

[Claims] 1 A stylus for surface tracing of a profiling cutting device in which an end mill corresponding to the stylus cuts a workpiece in a contoured manner, the stylus having a cylindrical shaft portion and a head formed at the tip thereof, the head having a corresponding shape. It is formed in the same shape as the head of the end mill, and the shaft is formed sufficiently larger than the outer diameter of the corresponding end mill.
A stylus for a profiling cutting device, characterized in that the lower end of the shaft is formed so that only the lower end of the shaft comes into contact with a steep slope on the surface of a model, and only the head comes into contact with a gentle slope.