KIM, Moon-ku (47-14 Samjeon-dong Songpa-gu, Seoul 138-838, KR)
CHO, Yun-gu (2cha Hyundai I-park Apt, Mangpo-dong Yeongtong-gu Suwon-si, Gyeonggi-do 443-770, 04-042 2, KR)
YEO, Soo-dong (1-406 Mido Apt, Bupyeong-dong Bupyeong-gu, Incheon 403-010, KR)
LEE, Jin-Hyung (6 Jugong Apt, Bugae 3-dong Bupyeong-gu, Incheon 403-732, 13-1901, KR)
KIM, Sun-Taek (379-6 Byeongjeom-ri Taean-eup, Hwaseong-si, Gyeonggi-do 445-974, KR)
KWAK, Byung-hyeuk (810 Wookuoung Sitebil, 768-1 Won-dong Osan-si, Gyeonggi-do 447-804, KR)
SUNG, Jong-mo (102-407 Hwanam Apt, 175 Galgot-dong Osan-si, Gyeonggi-do 447-707, KR)
YOON, Wang-dae (203ho, 561-7 Sucheong-dong Osan-si, Gyeonggi-do 447-290, KR)
CHOI, Sung-kyun (598 Botong-ri Jeongnam-myeon, Hwaseong-si, Gyeonggi-do 445-963, KR)
BAE, Kwang-ju (Na-302 Youngin-villa, Godeung-dong Paldal-gu Suwon-si, Gyeonggi-do 442-090, KR)
CHO, Yong-bum (808-1 Sachang-ri Yanggam-myeon, Hwaseong-si, Gyeonggi-do 445-932, KR)
KIM, Wan-ku (808-3 Sachang-ri, Yanggam-myeon Hwaseong-si, Gyeonggi-do 445-932, KR)
KIM, Moon-ku (47-14 Samjeon-dong Songpa-gu, Seoul 138-838, KR)
CHO, Yun-gu (2cha Hyundai I-park Apt, Mangpo-dong Yeongtong-gu Suwon-si, Gyeonggi-do 443-770, 04-042 2, KR)
YEO, Soo-dong (1-406 Mido Apt, Bupyeong-dong Bupyeong-gu, Incheon 403-010, KR)
LEE, Jin-Hyung (6 Jugong Apt, Bugae 3-dong Bupyeong-gu, Incheon 403-732, 13-1901, KR)
KIM, Sun-Taek (379-6 Byeongjeom-ri Taean-eup, Hwaseong-si, Gyeonggi-do 445-974, KR)
KWAK, Byung-hyeuk (810 Wookuoung Sitebil, 768-1 Won-dong Osan-si, Gyeonggi-do 447-804, KR)
SUNG, Jong-mo (102-407 Hwanam Apt, 175 Galgot-dong Osan-si, Gyeonggi-do 447-707, KR)
YOON, Wang-dae (203ho, 561-7 Sucheong-dong Osan-si, Gyeonggi-do 447-290, KR)
CHOI, Sung-kyun (598 Botong-ri Jeongnam-myeon, Hwaseong-si, Gyeonggi-do 445-963, KR)
BAE, Kwang-ju (Na-302 Youngin-villa, Godeung-dong Paldal-gu Suwon-si, Gyeonggi-do 442-090, KR)
CHO, Yong-bum (808-1 Sachang-ri Yanggam-myeon, Hwaseong-si, Gyeonggi-do 445-932, KR)
Claims
[1] A method for manufacturing a shank drill for drilling holes in boards, the method comprising: a mixing step (SlOO) of mixing 20-30 wt% of glass powder, 30-50 wt% of stone powder and 30-40 wt% of PPS resin with each other to provide a mixture; a melting step (S200) of heating and melting the mixture at a temperature of 320-340 0 C; an injection molding step (S300) of inserting a metal shank 10 in an injection mold and injecting the melted mixture into the mold at a pressure of 50-75 kg/cm
2 a cutting step (S400) of cooling a molded shank 20 resulting from the injection molding process (S300) and cutting the cooled shank to a given length; a molded shank-cutting step (S500) of cutting one end of the molded shank 20 into a conical shape such that a portion of the metal shank 10 is exposed; an air groove-forming step (S600) of forming an air groove 21 having an opened, curved cross-section on the outer circumference of the molded shank 20 in a longitudinal direction; and a flute-forming step (S700) of forming a spiral cut groove 11 on the outer circumference of the exposed metal shank 10 to form a flute 12.
[2] A shank drill for drilling holes in boards, comprising: a molded shank 20 formed by melting, compressing and hardening a mixture of
PPS resin, glass powder and stone powder; a metal shank 10 molded integrally with the molded shank 20 such that it is inserted into the molded shank 20 and has the same length as the molded shank
20; a flute 12 having a spiral cut groove 11 formed on a portion of the metal shank
10 exposed by cutting one end of the molded shank 20 in a tapered shape; and an air groove 21 formed on the outer circumference of the molded shank.
[3] The shank drill of Claim 2, wherein the spiral groove 11 in the flute 12 is formed in at least two rows on the outer circumference of the metal shank 10 in the axial direction of the metal shank 10, and the air groove 21 in the molded shank 20 is formed in at least two rows on the outer circumference of the molded shank 20 in the axial direction of the molded shank 20, in a way such that the air groove 21 is in the form of any one selected from among a straight line, which is the same as the axial direction of the molded shank 20, and a spiral, which is repeated in a constant cycle along the outer circumference of the molded shank in the axial direction of the molded shank.
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Description
MAKING METHOD OF SHANK DRILL AND SHANK DRILL FOR BOARD HALL PROCESSING
Technical Field
[1] The present invention relates to a method for manufacturing a shank drill for board hole formation and a shank drill manufactured thereby. More specifically, according to the present invention, a molded shank made of a mixture of glass powder, stone powder and PPS resin covers the outer surface of a metal shank, and thus the inventive shank drill has increased compression strength such that it can sufficiently resist pressure occurring in a process of chucking it to a collect chuck, and the metal shank can be prevented from being deformed due to high-temperature frictional or cutting heat generated during a process of drilling holes in printed circuit boards. In addition, the shank drill enables chip dust generated from boards during hole drilling to be collected and discharged together with the surrounding air to the outside through the air groove formed on the molded shank, so as to cool the flute and, at the same time, prevent the board dust from scattering throughout the surrounding environment, thus maintaining a pleasant working environment. Background Art
[2] Holes in printed circuit boards are formed using micron drills having diameters much smaller than those of generally used drills.
[3] Such micron drills comprise a shank, which is entirely made of tungsten and is chucked to a collect chuck, and a flute, which protrudes or extends from the tapered end of the shank in the axial direction of the shank to a given length and has a spiral cut groove formed thereon.
[4] However, the micron drills having such a structure have problems in that, because the shank and the flute have very different diameters, they require many processes and precise and expensive cutting tools for the processing thereof, resulting in an increase in the manufacturing time and cost of the micron drills. Also, during the use thereof, the flute protruding from the shank is frequently broken and, at the same time, is deteriorated due to cutting heat or frictional heat generated in a process of drilling holes, resulting in a decrease in the outer diameter roundness, cylindricity, straightness, etc. thereof.
[5] In an attempt to solve such problems, Korean Utility Model Registration No.
247214 (September 6, 2001) discloses a molded shank drill, which is molded such that a flute portion made of a metal material and having a flute extending from the front end thereof is inserted into the front end of a shank portion, made of a high-strength,
flame-resistant plastic material, to a given length. However, the disclosed molded shank drill has problems in that the shank portion has low compression strength, and thus is deformed during a process of chucking it to a collect chuck, resulting in a change in the outer diameter roundness, cylindricity and straightness thereof, leading to decreased precision of drilled holes. Also, the use of this drill has problems in that fine powder (chip) scatters throughout the surrounding environment to thus contaminate the working space, and working for long periods in this environment leads to occupational diseases such as respiratory diseases. Disclosure of Invention Technical Problem
[6] The present invention has been made in order to solve the above-described problems occurring in the prior art, and it is an object of the present invention to provide a method for manufacturing a shank drill for drilling holes in boards, which has increased mechanical compression strength, such that it can sufficiently resist pressure occurring in a process of chucking it to a collect chuck.
[7] Another object of the present invention is to provide a shank drill for drilling holes in boards, which enables fine dust generated from printed circuit boards during hole drilling to be discharged together with the surrounding air to the outside through an air groove formed on a molded shank, so as to cool the metal shank and, at the same time, prevent the board dust from scattering throughout the surrounding environment, thus maintaining a pleasant working environment.
Technical Solution
[8] To achieve the above objects, the present invention provides a method for manufacturing a shank drill for drilling holes in boards, the method comprising: a mixing step (SlOO) of mixing 20-30 wt% glass powder, 30-50 wt% stone powder and 30-40 wt% PPS resin with each other to provide a mixture; a melting step (S200) of heating and melting the mixture at a temperature of 320-340 0 C; an injection molding step (S300) of inserting a metal shank 10 in an injection mold and injecting the melted mixture into the mold at a pressure of 50-75 kg/cm ; a cutting step (S400) of cooling a molded shank 20, produced in the injection molding process (S300), and cutting the cooled molded shank 20 to a given length; a molded shank-cutting step (S500) of cutting one end of the molded shank 20 into a conical shape such that a portion of the metal shank 10 is exposed; an air groove-forming step (S600) of forming an air groove 21 having an opened, curved cross-section on the outer circumference of the molded shank 20 in a longitudinal direction; and a flute-forming step (S700) of forming a spiral cut groove 11 on the outer circumference of the exposed metal shank 10 to form a flute 12.
[9] In another aspect, the present invention provides a shank drill for drilling holes in boards, comprising: a molded shank 20 formed by melting, compressing and hardening a mixture of PPS resin, glass powder and stone powder; a metal shank 10 molded integrally with the molded shank 20 such that it is located in the molded shank 20 and has the same length as the molded shank 20; a flute 12 having a spiral cut groove 11 formed on a portion of the metal shank 10 exposed by cutting one end of the molded shank 20 in a tapered shape; and an air groove 21 formed on the outer circumference of the molded shank 20.
[10] Preferably, the spiral cut groove 11 in the flute 12 is formed in at least two rows on the outer circumference of the metal shank 10 along the axial direction of the metal shank 10, and the air groove 21 in the molded shank 20 is formed in at least two rows on the outer circumference of the molded shank 20 along the axial direction of the molded shank 20, in a way such that the air groove 21 is in the form of any one selected from among a straight line, which is the same as the axial direction of the molded shank 20, and a spiral, which is repeated in a constant cycle along the outer circumference of the molded shank in the axial direction of the molded shank.
Advantageous Effects
[11] As described above, according to the present invention, the molded shank made of a mixture of glass powder, stone powder and PPS resin and having a given thickness covers the outer surface of the metal shank, and thus the inventive shank drill has increased compression strength such that it can sufficiently resist pressure occurring in a process of chucking it to a collect chuck so as to prevent deterioration of outer diameter roundness, cylindricity and straightness, thus making it possible to form precise holes.
[12] Also, the inventive shank drill can be prevented from deforming, resulting from high-temperature frictional or cutting heat generated during a process of drilling holes in printed circuit boards, that is, it can be protected from distortion of the metal shank inserted into the molded shank.
[13] In addition, the shank drill enables chip dust generated from boards in a process of drilling holes to be collected and discharged together with the surrounding air to the outside through the air groove on the molded shank, so as to cool the flute and, at the same time, prevent the board dust from scattering throughout the surrounding environment, thus maintaining a pleasant working environment. Brief Description of the Drawings
[14] FIG. 1 is a flow chart showing the method for manufacturing a shank drill for drilling holes in boards according to the present invention.
[15] FIG. 2 is a perspective view of the shank drill for drilling holes in boards according
to the present invention.
[16] FIG. 3 is a perspective view showing the inner structure of the shank drill for drilling holes in boards according to the present invention.
[17] FIG. 4 is an enlarged cross-sectional view taken along line A-A in FIG. 2.
[18] FIG. 5 is a longitudinal cross-sectional view of a shank drill for drilling holes in boards according to another embodiment of the present invention. Best Mode for Carrying Out the Invention
[19] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.
[20] Before explaining a method for manufacturing a shank drill for drilling holes in boards according to the present invention, the shank drill manufactured using this method will be described. As shown in FIGS. 2 and 3, the shank drill consists of a metal shank 10 and a molded shank 20.
[21] The metal shank 10 has a function of sufficiently transferring a penetrating or cutting force, required in a process of forming a hole having a specific diameter at a given position in a printed circuit board (not shown), to a flute formed at the top of the metal shank 10. The molded shank 20 is formed on the outer surface of the metal shank 10, and thus the metal shank 10 can be easily chucked to a collect chuck of a drilling machine (not shown).
[22] Also, the metal shank is preferably made of a tungsten material such that it can sufficiently resist high-temperature frictional or cutting heat generated during a process of forming holes. Moreover, in order to increase the outer diameter roundness, cylindricity and straightness required for drilling precise holes, the metal shank 10 is preferably inserted into the molded shank 20 such that it extends from one end to the other end of the molded shank 20.
[23] Furthermore, the metal shank 10 extends integrally from a flute 12 having a spiral cut groove 11 at one exposed side of the molded shank 20, cut in a tapered shape.
[24] The spiral cut groove 11 is preferably formed in at least two rows on the outer circumference of the metal shank 10 along the axial direction of the metal shank 10.
[25] The molded shank 20 is constructed such that it enables the center of the metal shank 10 inserted therein to be precisely maintained, enables the metal shank to sufficiently resist pressure occurring in a process of chucking the metal shank to a collect chuck, can prevent fine dust, generated in a process of drilling holes in printed circuit boards, from being scattering throughout the surrounding environment, and can cool the flute 12, which extends integrally from the metal shank 10.
[26] For this purpose, the molded shank 20 is formed of a material obtained by melting, compressing and hardening a mixture of PPS resin, glass powder and stone powder,
and covers the entire surface of the metal shank 10, including both ends of the metal shank 10. In other words, the molded shank 20 is formed to have the same length as the metal shank 10.
[27] To increase its mechanical compression strength, the molded shank 20 is made of a material obtained by melting and hardening a mixture of 20-30 wt% glass powder, 30-50 wt% stone powder and 30-40 wt% PPS resin. In this respect, the glass powder and the stone powder preferably have particle sizes of 130-150 mesh and 150-170 mesh, respectively. More preferably, the glass powder and the stone powder have particle sizes of 140 mesh and 160 mesh, respectively.
[28] The mechanical compression strength of the molded shank 20 covering the metal shank 10 is preferably 6-9 kg/cm , and more preferably 7-8 kg/cm , such that it can sufficiently resist pressure occurring in a process of chucking the drill to a collect chuck.
[29] On the outer circumference of the molded shank 20, the air groove 21 is formed in at least two rows in the axial direction of the molded shank 20. Thus, when the drill rotates in a state in which it is coupled to a collect chuck (not shown), fine dust or the like generated in a process of forming holes in printed circuit boards will be sucked, together with the surrounding air, by the suction force of an air suction port connected with the collect chuck, and be collected in a separate dust collection filter through the air suction port.
[30] The method for manufacturing this shank drill will now be described. As shown in
FIG. 1, a mixture for forming the molded shank 20 is first obtained through a mixing step (SlOO) of mixing 20-30 wt% glass powder, 30-50 wt% stone powder and 30-40 wt% PPS resin. In this step, the glass powder and the stone powder preferably have particle sizes of 13-150 mesh and 150-170 mesh, respectively.
[31] Then, the mixture is subjected to a melting step (S200) of heating and melting the mixture at 320-340 0 C. The melted mixture is subjected to an injection molding step (S300) of injecting the melted mixture into an injection mold containing the metal shank 10 such that the surface of the metal shank 10 is covered with the melted mixture to a given thickness. In this step, the injection pressure of the melted mixture is preferably 50-75 kg/cm . Also, in order for the melted mixture to be easily injected into the injection mold, it is preferable that the temperature of the melted mixture be 320-340 0 C and that the temperature of the injection mold be maintained at 140-160 0 C.
[32] Then, a cutting step (S400) follows, in which the injection molded shank 20 having the metal shank 10 inserted therein is cooled and cut to a given length. Then, a molded shank-cutting step (S500) is carried out, in which one end of the molded shank 20 is cut in a tapered shape such that a portion of the metal shank 10 is exposed to the outside.
[33] Next, an air groove-forming step (S600) is carried out, in which an air groove 21 having an opened, curved cross section is formed on the outer circumference of the molded shank 20 in a longitudinal direction. Then, a flute-forming step (S700) is carried out, in which a spiral cut groove 11 is machined on the outer circumference of the metal shank 10 exposed in the cutting step (S400), thus forming a flute 12. In this way, the shank drill is manufactured.
[34]
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