JP2012148384A - Drill bit structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a drill bit structure having high rigidity as a whole and capable of increasing a chip housing space and chip removing capability.SOLUTION: The drill bit structure includes symmetrical first and second twist grooves. Each of the first and second twist grooves has at least two spiral tilt angles, a front stage tile angle and a rear stage tilt angle. The second twist groove having the front stage spiral tilt angle and the first twist groove having the front stage tilt angle are symmetrically separated, and the second twist groove having the rear stage spiral tilt angle is gradually coupled to the first twist groove having the rear stage tilt angle. The design of the drill bit structure provides an advantage of increasing rigidity as a whole, and additionally, maintains a chip housing space and chip removing capability equal to those of a known symmetrical two-groove drill bit.

Description

  The present invention relates to a drill bit structure, and in particular, by adjusting the multi-stage spiral inclination angle, the drill blade front stage has two symmetrical twist grooves and the drill blade rear stage has a single twist groove. The design relates to the drill bit structure.

  Due to the development of high-density printed circuit boards and high-precision wire thinning, drilling uses a large number of drills with extremely small blade diameters, and high quality and high demand for printed circuit boards in the market. Under the competition of short delivery times, drills are required to have high precision, high feed rate, good hole wall quality, and machining conditions that do not break during work. In order to improve work efficiency and reduce manufacturing costs, the through-hole drilling on the printed circuit board performs through-hole drilling on multiple overlapping printed circuit boards. Must have sufficient strength and rapid cutting scrap removal ability.

  Two known twisted grooves are formed in a known drill bit structure, and the conventional design of a general drill bit includes a chip containing space necessary for processing, a chip removing ability and a chip winding, a chip cutting Based on the tolerance of clogging, a helical twist angle of a single torsion groove is designed, which can be used for current low-machining machining conditions, but is difficult to machine, and contains cutting waste storage space and cutting When the debris removal capacity has to be increased, the swarf wrapping and swarf clogging has already reached the upper limit and cannot be readjusted, and the rigidity of the drill bit is also sensitive to the helical tilt angle.

  In order to obtain optimum cutting performance in another drill bit structure, the drill core thickness adopts a regular cone design method with the cone tip facing backward and extending diagonally, and such drill bit has a core thickness Gradually increases, and the space for storing the cutting waste at the rear stage of the drill bit gradually decreases. Therefore, the spiral inclination angle of the twist groove at the front end of the drill bit is small. The twisted spiral angle of the torsion groove is large, the cutting distance is long, and the cutting waste storage space is increased, which solves the problem that the cutting waste storage space at the rear stage of the drill bit is smaller than the front end. The design of the helical tilt angle creates serious chip wrapping problems, resulting in poor drill bit quality and breakage problems.

  The spiral inclination angle of the twist groove of the drill bit influences the cutting bit storage space and the chip removal capability of the drill bit. The larger the angle, the larger the cutting tip storage space. There are structures with a large front end of the spiral inclination angle and a small rear end, which increases the cutting waste storage space at the front end of the drill bit. Contrary to the phenomenon that the cutting waste storage space gradually decreases, the clogging of the cutting bit is likely to occur at the rear end of the drill bit, resulting in poor drill bit processing quality and breakage.

  A single helix angle or a small helix angle front end and a large rear end, or any design with a large helix angle front and a small rear end, the actual size of the drill bit cutting waste accommodating space is small. There are problems that do not match the required amount, and all have a negative impact on processing.

  In order to solve the above problems, the present invention provides a drill bit structure, and by adjusting the multi-stage spiral inclination angle, the drill blade front stage has two symmetrical twist grooves, and the drill blade rear stage is joined. It is an object of the present invention to have the advantage of increasing the rigidity and strength of the entire drill bit and increasing the cutting waste storage space and the cutting waste removal capability.

  In order to achieve the above object, a drill bit structure according to one embodiment of the present invention includes a shank and a drill blade connected to the shank, the drill blade having a first twist groove having a symmetrical cone tip. And the first twist groove and the second twist groove both have at least one front spiral angle and a rear spiral angle. The first twist groove and the second twist groove having the front spiral inclination angle are separated symmetrically, and the second twist groove having the rear spiral inclination angle is gradually combined with the first twist groove.

  The drill bit of the present invention has high rigidity of the entire drill bit, and increases the cutting waste storage space and cutting waste removal capability.

1 is an external plan view of a drill bit structure according to one embodiment of the present invention. It is an external appearance top view of the drill bit structure by another Example of this invention. FIG. 5 is a process capability index (CPK) comparison diagram of drilled hole position accuracy by the drill bit structure of the present invention and a known drill bit structure. It is a comparison figure of the inner wall roughness manufactured by the drill bit structure of this invention and a well-known drill bit structure. It is a comparison figure of a nail head of the drill bit structure of the present invention and a known drill bit structure.

  FIG. 1 is an external plan view of a drill bit structure according to an embodiment of the present invention. As shown in the figure, the drill bit structure 10 includes a shank 12 and a drill blade 14 connected to the shank 12. Each of the cutting blades 16 has two symmetrical cutting blades 16, and each cutting blade 16 extends rearward along the drill blades 14. Rotate to form two helical grooves and two helically symmetric twisted grooves. The two twist grooves are the first twist groove 20 and the second twist groove 22, respectively. For example, the first twist groove 20 and the second twist groove 22 both have a front spiral inclination angle and a rear spiral inclination angle, and the front spiral inclination angle and the rear spiral inclination angle of the first twist groove 20 are determined by the spiral inclination. The spiral inclination angle of the second twist groove 22 is the front spiral inclination angle θ2 and the rear spiral inclination angle θ3. In this embodiment, with respect to the center line of the drill blade 14, the second spiral groove angle θ3 of the second twist groove is larger than the front spiral angle θ2 of the second twist groove, and the second spiral groove has the front spiral angle θ2. 22 and the first spiral groove 20 having the front spiral inclination angle θ1 are separated symmetrically and have the rear spiral inclination angle θ3 as the front spiral inclination angle θ2 of the second twist groove 22 changes to the rear spiral inclination angle θ3. The second twisted groove 22 is gradually coupled to the first twisted groove 20 having the rear spiral inclination angle θ1.

  With continued reference to FIG. 1, in this embodiment, the helical inclination angle θ1 of the first twist groove 20 is kept constant, and the front helical inclination angle θ2 of the second twist groove 22 coincides with the helical inclination angle θ1. The first torsion groove 20 and the second torsion groove 22 in the front stage can maintain a symmetrical state with each other, and the second torsion groove 22 has a rear spiral inclination angle θ3 depending on the position required for the drill blade 14. The second helical groove 22 gradually merges with the first helical groove 20 to form a single groove and the coupling is made so that the helical inclination angle θ3 at the rear stage does not coincide with the inclination angle θ1 of the helical line. The cutting scrap removing ability of the subsequent first twist groove 20 and the second twist groove 22 can be maintained at the same level as when the first twist groove 20 and the second twist groove 22 are separated.

  FIG. 2 is an external plan view of a drill bit structure according to another embodiment of the present invention. As shown in the figure, the rear spiral inclination angle θ3 of the second twist groove 22 is smaller than the front spiral inclination angle θ2, and By appropriately adjusting the spiral inclination angle θ1, the front spiral inclination angle θ2, and the rear spiral inclination angle θ3, the second twist groove 22 and the first twist groove 20 in the front stage maintain a symmetrical state with each other. The second twisted groove 22 at the rear stage gradually merges with the first twisted groove 20 to form one groove.

  Further, the change in the angle of the helical inclination angle of the second twisted groove 22 is not limited to the above-described two-stage design, and may be a multistage design, and the helical inclination angle of the first twisted groove 20 is limited to one type. Not. Further, the boundary position where the difference between the front spiral inclination angle and the rear spiral inclination angle changes is not limited to an arbitrary position from the tip of the drill blade to the tail edge of the drill blade, and the angle between the front spiral inclination angle and the rear spiral inclination angle. Can be arbitrarily changed from 5 degrees to 85 degrees. Further, in the present invention, by simultaneously adjusting the shapes of the spiral inclination angles of the first twist groove 20 and the second twist groove 22 at an arbitrary position of the drill blade 14, the drill blade 14 is symmetric with respect to each other. The twisted groove is merged into a single twisted groove, which greatly reduces the amount of grinding of the drill blade itself and achieves the effect of strengthening the rigidity. The groove shape and angle can be adjusted, and the purpose of increasing the cutting waste storage space and cutting waste removal capability can be achieved.

  FIG. 3 is a process capability index (CPK) comparison diagram of drilled hole position accuracy according to the drill bit structure of the present invention and the known drill bit structure. The diameter of the drill bit structure is 0.30 mm (mm) and the twist groove of the known drill bit structure has a single helical inclination angle, and the drill bit structure of the present invention has two symmetrical twist grooves. In FIG. 3, ▲ indicates the CPK of the known drill bit structure, ◆ indicates the CPK of the drill bit structure of the present invention, and ◯ indicates the CPK of the drill bit structure of the present invention. As shown in FIG. 3, the CPK value of the drill bit structure of the present invention is higher than the CPK value of the known drill bit structure. The structure has a preferable hole position accuracy.

  FIG. 4 is a comparison diagram of the inner wall roughness (Roughness) produced by the drill bit structure of the present invention and the known drill bit structure, and the drill diameters of the drill bit of the present invention and the known drill bit are both 0. .30 mm (mm), the known drill bit structure twist groove has a single helical tilt angle, and the drill bit structure of the present invention comprises two mutually symmetrical twist grooves in a single twist. In FIG. 4, ▲ indicates the inner wall roughness of the known drill bit structure, ◆ indicates the inner wall roughness of the drill bit structure of the present invention, and ○ indicates each FIG. 4 shows an average value of the coarse degree, and as can be seen from FIG. 4, the inner wall roughness of the drill bit structure of the present invention is slightly lower than the rough degree of the hole wall of the known drill bit structure. Is a public It is possible to achieve the same hole wall quality as the drill bit structures.

  FIG. 5 is a comparison diagram of a nail head between the drill bit structure of the present invention and the known drill bit structure. The drill diameters of the drill bit of the present invention and the known drill bit are all 0.30 mm. (Mm), the known drill bit structure twist groove has a single helical inclination angle, and the drill bit structure of the present invention combines two mutually symmetrical twist grooves into a single twist groove. In FIG. 5, ▲ indicates the performance of the nail head having the known drill bit structure, ◆ indicates the performance of the nail head having the drill bit structure of the present invention, and ○ indicates each performance FIG. 5 shows an average value of the performance of the nail head, and as can be seen from FIG. 5, the performance of the nail head of the drill bit structure of the present invention is slightly lower than that of the known drill bit structure nail head. Drill bit structures of the present invention has a homology of drill quality and well-known drill bit structures.

  In summary, in the present invention, the drill bit is not only strengthened by the technique of merging two mutually symmetrical torsion grooves into a single groove by a multi-stage spiral inclination angle, but also the two known mutual mutual strengths. Therefore, it is possible to maintain the same chip waste storage space and chip removal capability as those of a symmetrically twisted grooved drill bit.

  In the present invention, preferred embodiments have been disclosed as described above. However, the present invention is not limited to the present invention, and any person who is familiar with the technology can use various methods within the spirit and scope of the present invention. Variations and moist colors can be added, so the protection scope of the present invention is based on what is specified in the claims.

DESCRIPTION OF SYMBOLS 10 Drill bit structure 12 Shank 14 Drill blade 16 Cutting blade 18 Side blade 20 1st torsion groove 22 2nd torsion groove θ1 Spiral inclination angle θ2 Previous spiral inclination angle θ3 Rear spiral inclination angle

Claims (6)

A drill bit structure,
Shank,
A drill blade connected to the shank, wherein the drill blade spirally installs a first twist groove and a second twist groove whose conical tips are symmetrical, and the first twist groove and the second twist groove. Both have at least one front spiral inclination angle and a rear spiral inclination angle, and the second twist groove having the front spiral inclination angle and the first twist groove having the front spiral inclination angle are symmetrical. The drill bit structure according to claim 1, wherein the second twist groove having the rear spiral inclination angle is gradually coupled to the first twist groove having the rear spiral inclination angle.   2. The drill bit structure according to claim 1, wherein the front spiral inclination angle of the first twist groove coincides with the front spiral inclination angle of the second twist groove.   3. The drill bit according to claim 1, wherein the rear spiral inclination angle of the second twist groove is larger than the front spiral inclination angle of the second twist groove with respect to a center line of the drill blade. Construction.   3. The drill bit structure according to claim 1, wherein a second spiral inclination angle of the second twist groove is smaller than a first spiral inclination angle of the second twist groove with respect to a center line of the drill blade.   The position at which the front spiral inclination angle between the first twist groove and the second twist groove changes to the rear spiral inclination angle is an arbitrary position from the tip of the drill blade to the tail end of the drill blade. The drill bit structure according to any one of claims 1 to 4, wherein the drill bit structure is provided.   6. The angle of the front spiral inclination angle and the rear spiral inclination angle between the first twist groove and the second twist groove is 5 to 85 degrees. Drill bit structure according to item.