Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
  • B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
  • B21D22/00—Shaping without cutting, by stamping, spinning, or deep-drawing
  • B21D22/20—Deep-drawing
  • B21D22/21—Deep-drawing without fixing the border of the blank
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
  • B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
  • B21D22/00—Shaping without cutting, by stamping, spinning, or deep-drawing
  • B21D22/20—Deep-drawing
  • B21D22/201—Work-pieces; preparation of the work-pieces, e.g. lubricating, coating
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
  • B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
  • B21D22/00—Shaping without cutting, by stamping, spinning, or deep-drawing
  • B21D22/20—Deep-drawing
  • B21D22/24—Deep-drawing involving two drawing operations having effects in opposite directions with respect to the blank
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
  • B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
  • B21D24/00—Special deep-drawing arrangements in, or in connection with, presses
  • B21D24/005—Multi-stage presses
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
  • B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
  • B21D24/00—Special deep-drawing arrangements in, or in connection with, presses
  • B21D24/16—Additional equipment in association with the tools, e.g. for shearing, for trimming
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
  • B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
  • B21D31/00—Other methods for working sheet metal, metal tubes, metal profiles
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
  • B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
  • B21D35/00—Combined processes according to or processes combined with methods covered by groups B21D1/00 - B21D31/00
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
  • B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
  • B21D53/00—Making other particular articles
  • B21D53/24—Making other particular articles nuts or like thread-engaging members

Definitions

• the present invention relates to a stud and a method of fabricating the same, and more particularly, to a stud and a method of fabricating the same, in which a female screw portion of the stud is formed in a cup shape by means of a reverse drawing process, thereby preventing damage of the female screw portion due to vibration and torque and solving a problem of quality degradation of various electronic products due to generation of burrs.
• Background Art
• a stud is utilized to connect various electronic products to a PCB, and a mechanical machined stud has been chiefly employed for the stud.
• various studs such as a forged stud, a stud fabricated by means of a collar drawing process, a stud fabricated by means of a tube drawing process have been used.
• the mechanical machined stud has a disadvantage that productivity is degraded remarkably, and the forged stud has lots of limitations depending on a shape and a structure of the stud and has a problem of precision degree caused by a change of the size due to hot formation at the time of the forging.
• the present invention has been devised to solve several problems originated from the conventional studs fabricated by various processes as described above, and it is an object of the present invention to provide a stud and a method of fabricating the same, in which a female screw portion of the stud fabricated by a collar drawing process can be formed in a cup shape by means of a reverse drawing process, thereby stabilizing the female screw portion structurally, ensuring prevention of damages of the female screw portion due to vibration and rotation torque through formation of the strong female screw portion, and preventing fatal defects of the electronic products caused by the burrs.
• the present invention provides a method of fabricating a stud, comprising the steps of: performing a deep drawing on a metal plate at a round shaped blank into a cup-shaped blank to thereby form a flange portion; performing a plurality of drawing processes again for reducing a diameter of the cup-shaped blank to thereby complete a body portion; performing a reverse drawing to form a female screw portion at the body portion; and forming a press-fit fastening groove at a contact surface of the body portion and the flange portion by means of a slitting process, and performing a trimming process to fabricate the stud.
• the present invention may further comprise performing a plurality of embossing processes to form a protrusion portion acting as a guide when assembled with corresponding mating parts after forming the female screw portion and the flange portion or performing a piercing process on a lower end portion of the female screw portion to fabricate the stud formed with a piercing portion.
• FIG. 1 is a cross-sectional view showing a use state of a stud fabricated by a conventional method of collar drawing process
• FIG. 2 is a cross-sectional view showing a use state of a stud fabricated according to a method of fabricating a stud of the present invention
• FIG. 3 is a view showing a process of fabricating a standard stud made of metal plate according to the present invention
• FIG. 4 is a view showing a process of fabricating an embossed standard stud according to the present invention.
• FIG. 5 is a view showing a result of CAE analysis of a first deep drawing formation step for fabricating a metal plate stud according to the present invention
• FIG. 6 is a view showing a result of CAE analysis of a second deep drawing formation step for fabricating a metal plate stud according to the present invention
• FIG. 7 is a view showing a result of CAE analysis of a third deep drawing formation step for fabricating a metal plate stud according to the present invention
• FIG. 8 is a view showing a result of CAE analysis of a fourth deep drawing formation step for fabricating a metal plate stud according to the present invention
• FIG. 9 is a view showing a result of CAE analysis of a fifth deep drawing formation step for fabricating a metal plate stud according to the present invention
• FIG. 20 is a view showing a result of CAE analysis of a fifth deep drawing formation step for fabricating a metal plate stud according to the present invention.
• FIG. 10 is a view showing a result of CAE analysis of a sixth deep drawing formation step for fabricating a metal plate stud according to the present invention
• FIG. 11 is a view showing a result of CAE analysis of a seventh deep drawing formation step for fabricating a metal plate stud according to the present invention
• FIG. 12 is a view showing a result of CAE analysis of an eighth deep drawing formation step for fabricating a metal plate stud according to the present invention
• FIG. 13 is a view showing a result of formation analysis of an assembly state of a metal plate stud according to the present invention
• FIG. 14 is a view showing a result of formation analysis of an assembly state of a metal plate stud according to the present invention
• FIG. 25 FIG.
• FIG. 15 is a view showing a result of sectional analysis of an assembly state before the press-fit of the metal plate stud according to the present invention
• FIG. 16 is a view showing a result of sectional analysis of an assembly state after the press-fit of the metal plate stud according to the present invention
• FIG. 17 is a view showing a result of stress analysis of a metal plate stud according to the present invention
• FIG. 18 is a view showing a result of planar analysis of an assembly state before the press-fit of the metal plate stud according to the present invention
• FIG. 19 is a view showing a result of planar analysis of an assembly state after the press-fit of the metal plate stud according to the present invention
• FIG. 30 FIG.
• FIG. 20 is a view showing a result of stress distribution state analysis after the completion of the press-fit of the metal plate stud according to the present invention
• FIG. 21 is a view showing a result of analysis of tensile test of a conventional mechanical machined stud
• FIG. 22 is a view showing a result of analysis of tensile test (result of load analysis) of a conventional mechanical machined stud
• FIG. 23 is a view showing a result of test analysis of stress deformation behavior produced from a stud, a joint base metal, and a bolt, by fastening the bolt into the metal plate stud of the present invention and applying tensile load thereto;
• FIG. 21 is a view showing a result of analysis of tensile test of a conventional mechanical machined stud
• FIG. 22 is a view showing a result of analysis of tensile test (result of load analysis) of a conventional mechanical machined stud
• FIG. 23 is a view showing a result of test analysis
• FIG. 24 is a view showing a result of tensile test analysis (result of load analysis) of a metal plate stud of the present invention
• FIG. 25 is an actual article photograph of a material test machine for testing a test- piece to fabricate a metal plate stud according to the present invention
• FIG. 26 is an actual article photograph showing a test-piece before test to fabricate a metal plate stud according to the present invention
• FIG. 27 is an actual article photograph showing a test-piece after test to fabricate a metal plate stud according to the present invention
• FIG. 28 is a graph showing a result of tensile test of a metal plate stud and a mechanical machined stud according to the present invention
• FIG. 39 FIG.
• FIG. 29 is a graph showing a result of compression test of a metal plate stud and a mechanical machined stud according to the present invention
• FIG. 30 is a graph showing a result of side force test of a metal plate stud and a mechanical machined stud according to the present invention
• FIG. 31 is a table showing a result of test of test-pieces of a metal plate stud according to the present invention
• FIG. 32 is a view showing a process of fabricating a metal plate pierced stud according to another embodiment of the present invention.
• FIG. 2 is a cross-sectional view showing a construction of a stud 1 fabricated according to the present invention
• FIGs. 3 and 4 are process views of a standard stud 1 and a protruded standard stud 1 among studs 1 according to the present invention.
• the present invention will be described at first with reference to these drawings, in which identical elements are denoted by identical numerals.
• the stud 1 of the present invention is characterized by forming as a cup shape by means of a reverse drawing process to form a female screw portion 2 at the stud 1 , which is fabricated by means of a collar drawing process disclosed in Korean patent
• FIG. 3 is a fabricating process view of a standard stud among the metal plate studs according to the present invention, in which a primary drawing process is carried out on a round blank of a metal plate state into a cup shape to form a flange portion, and a plurality of drawing processes is performed again to reduce a diameter of the cup- shaped portion, thereby completing a body portion thereof.
• a drawing ratio is determined depending on a diameter of the thickness of material, and a diameter of a material, and a process design is carried out according to the determined drawing ratio.
• the cup shaped formation product with completed body portion has a flat plane whose flange portion is vertical with respect to a cylindrical centerline. Thereafter, a process progresses to accomplish the female screw portion of the stud by the formation of a bottom portion thereof.
• the female screw portion is formed by means of the reverse drawing process.
• the drawing ratio at the time of the reverse drawing is determined based on the material, and the thickness of the material.
• the intermediate formation body including completed female screw portion is shaped to form a slitting groove for the press-fit of the flange portion, so that it can be formed as a recessed form with respect to the thickness of the material from the basic surface of the flange.
• a press-fit fastening groove is formed by means of a slitting process, and a trimming process is carried out, and then a final formation body can be accomplished.
• FIG. 4 is a view showing a process of fabricating an embossed standard stud among the studs of the present invention, in which the embossed standard stud is accomplished according to a formation process similar to the standard stud forming process.
• the stud is completed by a process to which a plurality of emboss forming processes is added, so as to form protrusions acting as a guide, when the female screw portion and the flange portion are formed and assembled with corresponding mating parts.
• FIGs. 5 through 11 are views showing results of CAE analysis in a deep drawing process of a stud according to the present invention, in which the first formation step (FIG. 5) is a view showing an analysis result for preparing a process of carrying out a primary drawing in the blank.
• a punch is positioned at the upper portion and a die is positioned at the lower portion.
• a size of the punch, a size of the die, a diameter of the punch, and a diameter of the die are identical with those of the actual process design.
• a shape and a size of the blank to be formed are positioned between the punch and the die.
• the second formation step shows an analysis procedure of the primary drawing step.
• the cup shaped formation body is obtained when the metal plate is moved following the shape of the punch radius and the die shape together with the descending of the punch. According to the result of the formation analysis, it is confirmed that the formation is possible without any badness of the material such as puncture, burst, wrinkles, and the like.
• the third formation step (FIG. 7) is an analysis procedure for completing a cup shaped drawn intermediate formation body.
• the whole shape shows that formation is carried out without any difficulty. While the thickness of the material at the radius portion of the punch is thinnest and the thickness of the material at the distal end of the opening is thickest, it is shown that the process can be properly completed by the control of the formation speed and the stroke.
• the fourth formation step is an analysis procedure of a process of forming the cup shaped formation body by reducing the diameter of the cup shaped formation body.
• the fifth formation step (FIG. 9) shows an analysis procedure of a drawing process of the diameter-reduced cup shaped formation body. In this step, an intermediate formation product is completed according to the shape of the punch, and there was not found any problem in the process.
• the sixth formation step shows an analysis procedure of a drawing process of reducing the diameter of the cup shaped intermediate formation product again. It was confirmed that formation is smoothly carried out without producing any side wrinkles at the cup shaped intermediate formation body.
• the seventh formation step shows an analysis procedure of a reverse drawing process of a bottom portion.
• the reverse drawing process is to push a plate member of the bottom portion from the inside of the die together with the ascending of the punch.
• clearances between the diameter of the punch and the diameter of the die, and between the punch and the die are principal process factors, and the drawing ratio is determined based on the material, and the thickness of the material.
• the eighth formation step shows an analysis result of a reverse drawing process, which is further progressed. It is confirmed that a plastic working can be carried out smoothly according to the shape of the punch and the shape of the die based on the formation material of the bottom portion.
• FIG. 13 shows an analysis result of forming the press-fit portion of the lower flange portion of the stud fabricated according to the present invention, in which the press-fit of the slitting groove with the joint base metal is completed. It is shown that stress is concentrated on a portion adjoining the completion portion of the press-fit of the hexagonal flange portion, and the slitting groove with the joint base metal.
• FIG. 14 shows a formation analysis for observing the shape change of the press-fit portion, after the press-fit of the stud fabricated according to the present invention and the joint base metal.
• FIG. 15 is a view showing a result of sectional analysis of an assembly state before the press-fit of the metal plate stud according to the present invention.
• the principle of the press-fit is to insert the metal plate stud into a hole of the base metal to be joined, and pressurize it by means of the action of the punch and the die to join them by the deformation of the slitting groove and the base metal.
• FIG. 16 is a view showing an analysis obtained after the completion of the press-fit of the metal plate stud according to the present invention by means of the application of the load of the punch and the die.
• FIG. 17 is a view showing a result of stress analysis of a metal plate stud according to the present invention after the completion of the press-fit process of the stud. It is shown that stress is concentrated on the flange portion, and it is confirmed that the thickness of the flange portion was deformed thin due to the compression load.
• FIG. 18 is a view showing a result of planar analysis of an assembly state before the press-fit of the stud. It is observed clearly that a rectangular groove was formed at the slitting portion.
• FIG. 19 is a view showing a result of planar analysis of an assembly state after the completion of the press-fit of the stud. It is shown that the rectangular groove is plastic deformed so that it is press-fittingly coined into the joint base metal. The linear portion of the distal end of the flange is plastic deformed by the compression load so that the linear portion is changed into an irregular curve portion.
• FIG. 20 shows an analysis result of the stress distribution state after the press-fit of the stud. Where the maximum stress is produced and distributed with respect to the compression load, is the flange portion. In addition, the stress is chiefly concentrated on the circumference of the flange portion of the joint base metal.
• FIG. 21 is a view showing a result of test analysis of a stress deformation behavior produced from a stud, a joint base metal, and a bolt, by fastening the bolt to the conventional mechanical machined stud and applying the tensile load thereto.
• the maximum load was about 2,40ON
• the time consumed for the start of the isolation was about 0.5 seconds.
• FIG. 22 is a view showing a test analysis result of stress deformation behavior produced from a stud, a joint base metal, and a bolt, by fastening the bolt to the metal plate stud of the present invention, and applying the tensile load thereto.
• the maximum load was about 2,30ON
• the time consumed for the start of the isolation was about 1 seconds.
• FIG. 23 is a view showing a result of test analysis of stress deformation behavior of a metal plate stud of the present invention.
• FIG. 24 is a view showing an analysis result (result of load analysis) of tensile test of a metal plate stud of the present invention.
• FIG. 25 is a photograph showing an actual article of a material test system(MTS) for testing a test-piece of the stud fabricated according to the present invention, in which the material test system (MTS) is called as an 'MTS 858 TEST FRAME' (manufacturing company: MTS SYSTEM Corp., Manufacturing country: USA), and the force capacity is 25 kN, the maximum pressure is 70 bar/l,000psi, and the temperature range falls in a range of -18 0 C(O 0 F) - 65 0 C(15O 0 F).
• MTS material test system
• FIGs. 26 and 27 show photographs of actual articles of the test product obtained before and after the test. Total numbers of 25 test-pieces have been used to carry out the test.
• the joint base metal was GALVALUME (AZ120 organic coating) by 0.8t, and the test-pieces were fabricated in the press formation apparatus constructed of punches and dies.
• the test-piece shown in FIG. 27 shows a portion of the test-piece completed of the test. The test-piece was completed of the tensile, compression, and side force tests.
• FIGs. 28, 29 and 30 are graphs showing comparisons between the results of tensile test, compression test, and side force test of the test-pieces of the metal plate stud of the present invention and the conventional mechanical machined stud.
• the distance for the stud to be separated from the joint base metal was 2.7mm for the mechanical machined stud and 3.8mm for the metal plate stud, so it was confirmed that the metal plate stud has a higher value than the mechanical machined stud by 140%.
• the maximum load of the mechanical machined stud was 40kgf, and the maximum load of the metal plate stud was 42kgf, so that the maximum load of the metal plate stud was higher than that of the mechanical machined stud by 5%.
• the distance for the stud to be separated from the joint base metal was 3.8mm for the mechanical machined stud and 5.0mm for the metal plate stud, so it was confirmed that the metal plate stud has a higher value than the mechanical machined stud by 31%.
• FIG. 31 shows another embodiment of the present invention, in which a fabrication process diagram of the metal plate pierced stud is shown.
• the pierced stud 1 is used in the manufacturing of PDP, LCD, and the like, and constructed by forming a piercing portion 6, which penetrates through a female screw portion.
• PDP and LCD
• the stud and the method of fabricating the same according to the present invention has advantageous and remarkable effects in that it is possible form a female screw portion of the stud fabricated by a collar drawing process in a cup shape by means of a reverse drawing process, thereby stabilizing the female screw portion structurally, ensuring prevention of damages of the female screw portion due to vibration and rotation torque through formation of the strong female screw portion, and preventing fatal defects of the electronic products caused by the burrs at the time of fastening the bolt to the female screw portion.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Shaping Metal By Deep-Drawing, Or The Like (AREA)

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Publications (1)

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Citations (4)

Family Cites Families (6)

• 2007
  • 2007-04-30 KR KR1020070042104A patent/KR20070051822A/ko not_active Application Discontinuation
  • 2007-11-06 WO PCT/KR2007/005564 patent/WO2008133385A1/en active Application Filing
  • 2007-11-15 US US11/940,639 patent/US20080264137A1/en not_active Abandoned

Patent Citations (4)

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