JPH03213204A - How to drill holes in plate material with a drill - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a method for drilling holes in plate materials using a drill. Ru.

[Conventional technology]

For example, as disclosed in Japanese Patent Application Laid-Open No. 136705/1983, a method for drilling holes with good positional accuracy involves first performing countersunk machining using a drill with a short blade length and high bending rigidity. Another method is to drill through the hole using a drill with a long blade. Further, as a method for drilling holes in a thick substrate, for example, Japanese Patent Application Laid-Open No. 159310/1983 discloses a method in which holes are drilled from both sides of the workpiece using a drill with a short blade length.

[Problem to be solved by the invention]

In the conventional technology described above, hole bending is often caused by asymmetry of the drill bit length or non-uniformity of the workpiece material. Therefore, even if the positional accuracy is initially good with the guide hole,
As long as a drill with a long blade is used, bending will inevitably occur internally, so there is a limit to the accuracy of hole positioning on the exit side of the drill. Furthermore, even if a drill with a short blade length is used to drill holes from both sides, the drill will always bend to some degree, so there will always be discrepancies in the holes drilled from both sides. and,
This becomes a problem as the aspect ratio of the hole increases. However, conventional techniques have not taken these points into consideration.

An object of the present invention is to provide a method for processing a through hole with high positional accuracy.

[Means to solve the problem]

In order to achieve the above object, the method of drilling a hole in a plate material using a drill according to the present invention includes the following steps: The length of the blade is shorter than the thickness of the plate material from one side of the plate material, and the diameter thereof is smaller than the final required hole diameter. After drilling a hole with a thin first drill, on the other side of the plate material, at a position opposite to the hole drilled with the first drill, a hole with a blade length longer than the thickness of the plate material after processing is placed. The method is characterized in that the through hole is drilled by a second drill having a diameter such that the hole finally has the required hole diameter.

[Effect]

The drill used in the first step of the present invention is thinner than the final required hole diameter, but has a blade length shorter than the thickness of the workpiece.
It plays the role of machining a pilot hole with less bending of the hole. Also,
The drill that is used for machining from the opposite side in the second step of the present invention and that produces the final required hole diameter after machining will be By selecting the diameter and blade length of the first sewage drill so that they are within the drilling range of the drill to be processed, it is possible to machine holes without misalignment where the holes drilled from both sides meet.

Furthermore, even if the length of the drill bit used to drill a hole equal to the diameter of the final hole required later is greater than the thickness of the workpiece, the first hole drilled serves as a guide. Holes with good positional accuracy can be machined without bending.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

111M is an explanatory diagram of a method for drilling a hole in a plate material using a drill according to an embodiment of the present invention, and FIG. 2 is an explanatory diagram showing the relationship between the diameters of a sewage drill and a finishing drill.

In these figures, ■ is a small-diameter, short-length drill for drilling a pilot hole, IP is a pilot hole, 2 is a finishing drill with a blade length to finally drill a hole of the required diameter, and 2P is a drill with a long blade for drilling a hole of the final required diameter. Pilot hole I
A hole of the final required size is machined from the other surface facing P, and 3 is the work material.

First, as shown in FIG. 1(a), a pilot hole 1P that is thinner and shallower than the final required diameter is drilled in one surface of the workpiece 3 using a sewage drill 1. In general, the bending rigidity of a drill, which has the greatest effect on hole bending, is inversely proportional to the cube of the blade length, so by using a sewage drill with a short blade length, variations in hole position can be minimized.

Next, as shown in Fig. 1(b), the workpiece 3 is turned over,
A drilled hole 2P is formed on the other surface of the workpiece 3 facing the prepared hole TP using a drill 2 having the final required diameter and a blade length longer than the plate thickness W of the workpiece 3. Drilling is continued, and finally, a through hole 2H is formed using a finishing drill 2, as shown in FIG. 1(C). At this time, as shown in Figure 1 (a
In the process of ), slight variations in the hole position occur, and as shown in Fig. 2(a), a bend ∆ of the hole occurs inside the hole.
As shown in Fig. 2(b), by determining the dimensional relationship between the drill for the prepared hole IP and the finishing drill so that the diameter of the drill used for the next finishing process is larger than this bending displacement amount 2Δ. , it is possible to prevent misalignment of the holes at the part where both holes IP12P meet. Furthermore, when the through hole 2H is machined with the finishing drill 2, the prepared hole serves as a guide, so that the hole does not bend as would be the case when the through hole 2H is directly machined using only the finishing drill 2. In addition, in FIG. 2, 1B indicates a hole when a bend actually occurs and is machined.

For example, when processing a through hole with a diameter of 0.4-1 on a printed circuit board with a board thickness of 51cm, the diameter is 0.3N and the blade length is 3.5+n.
After drilling a pilot hole with a depth of approximately 2.5I1m using a drill, the positioning accuracy can be improved by drilling a through hole from the opposite side using a drill with a diameter of 0.4m and a blade length of 6ml. .

〔Effect of the invention〕

According to the present invention, a small diameter hole is first drilled from one side of the plate material, and a through hole of the final required size is drilled from the other side of the plate material at a position opposite to this small diameter hole. Therefore, a through hole can be formed with good positional accuracy.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of a method of drilling a hole in a plate material using a drill according to an embodiment of the present invention, and FIG. 2 is an explanatory diagram showing the relationship between the diameters of a sewage drill and a finishing drill. 1; Sewage drill lP; Prepared hole 2: Finishing drill 2H: Through hole 3; Work material flash diagram Ft

Claims (1)

[Claims] 1. In the method of drilling a hole in a plate material with a drill, the blade length is shorter than the thickness of the plate material from one side of the plate material,
After drilling a hole with a first drill whose diameter is smaller than the final required hole diameter, a blade with a length of A method for drilling a hole in a plate material using a drill, characterized in that a second drill is used to make a through hole that is longer than the thickness of the plate material and has a diameter such that the hole after processing has a final required hole diameter.