JP2006123066A - Grooving grinding method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a grooving grinding method for machining grooves of predetermined grinding finish width with high accuracy in a short time and at a low cost while reducing a machining time. <P>SOLUTION: Grooving grinding is performed for workpieces 12, 13, 14, 15 by reciprocating the workpieces 12, 13, 14, 15 in the extended direction of the grooves 18 while continuously carrying out depth of cuts of a rotating grinding wheel 7 and periodically reciprocating the grinding wheel 7 in the width direction of the grooves 18 within the finish width of the grooves 18. When the depth of cut of the grinding wheel becomes the set depth of the groove 18, grooving grinding with the grinding wheel 7 is completed. The grooves of set width and set depth are thus formed. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention provides, for example, grinding a punching die having grooves such as a punching die having a plurality of grooves in a comb blade shape used for punching a lead frame for mounting a semiconductor chip by pressing. The present invention relates to a technical field of a grooving grinding method for grooving when manufacturing.

  Conventionally, for example, a metal lead frame is used for mounting a semiconductor chip, and this lead frame has a large number of leads formed in a predetermined pattern. Such a lead frame is manufactured by punching using a comb-shaped punching die.

Since the comb-blade punching die has a large number of grooves, in order to produce this comb-blade punching die, it is necessary to perform grooving to form a large number of grooves. There is.
As a conventional grooving process, as shown in FIG. 6, it is known to form a large number of grooves a arranged in a comb blade shape on a workpiece b by grinding.

  As shown in FIG. 7, the side surface of the grinding wheel c for grooving the workpiece b is dressed to adjust the thickness of the grinding wheel c to the predetermined grinding finish width of the groove a, and the groove a There is known a method in which a grooving process is performed by giving a cutting stone having a cutting depth equal to a predetermined depth to a grindstone c (for example, see Non-Patent Document 1).

  In the grooving grinding method disclosed in Non-Patent Document 1, when the side surface of the grindstone is worn and the thickness dimension of the grindstone c is reduced, the dimension of the groove a to be machined is also smaller than the dimension of the predetermined grinding finish width. End up. Therefore, if the side surface of the grindstone is worn and the thickness dimension decreases, it is necessary to replace the grindstone itself. For this reason, there is a problem that not only the replacement frequency of the grindstone c is increased, labor and time required for the replacement, but also the manufacturing cost is increased.

Therefore, as shown in FIGS. 8 (a) and 8 (b), a grinding wheel whose thickness is set to be smaller than the grinding finish width dimension of the groove a and slightly larger than half the grinding finish width dimension of the groove a by side dressing. A grooving grinding method using c has been proposed. In this grooving grinding method, first, as shown in FIG. 8A, the grindstone c is to be machined with respect to the workpiece b, and is equal to a predetermined finishing depth of the groove a on one side (left side) of the groove a. An incision amount of incision is given to the grinding wheel c to grind a groove a ′ having a width smaller than a predetermined grinding finish width on one side of the groove a, and then grinding as shown in FIG. After moving the grindstone c by a predetermined amount in the width direction (right direction) of the groove a, the workpiece c is cut to the predetermined finish depth of the groove a on one side (right side) opposite to the groove a to be machined. Thus, the groove a having a predetermined grinding finish width is ground in two steps of grinding. According to this grooving grinding method, even if the side surface of the grindstone is worn and the thickness is reduced, the groove a having a predetermined grinding finish width is obtained by correcting the movement of the grindstone c in the groove width direction. Therefore, compared with the grooving grinding method shown in FIG. 7 described above, the replacement frequency of the grinding wheel c is reduced, so that the labor and time required for the replacement can be saved and the manufacturing cost can be saved. Can be suppressed.
Dekaban Skills Book 7 Grinder Utilization Manual, Editing Tool Engineer Editorial Department, 3rd Edition, published on June 5, 2001 (published by Okawa Publishing Co., Ltd., page 102 and Fig. 3 “Grinder Performance”) Example of processing]

However, in the grooving grinding method shown in FIGS. 8 (a) and 8 (b), since the grinding process is performed in two steps, a lot of processing time is required (grooving grinding process shown in FIG. 7). It takes about twice as long as the method).
In addition, at the time of the second grinding process shown in FIG. 8B, the groove opening at the edge of the workpiece b is widened due to the escape (falling) of the grindstone c, resulting in a groove a having a wide opening. There is a problem that it is difficult to form the groove a having a predetermined grinding finish width, and the processing accuracy is lowered.

  The present invention has been made in view of such circumstances, and an object thereof is to process a groove having a predetermined grinding finish width with high accuracy, in a short time, and at low cost while reducing the processing time. It is to provide a grooving grinding method that can be used.

In order to solve the above-mentioned problems, the invention of claim 1 sets a notch of a grinding wheel with respect to a workpiece, and reciprocates in the extending direction of a groove forming the workpiece while rotating the grinding wheel. In the grooving grinding method for forming a groove in the work by performing grinding, the work is performed while periodically reciprocating the grinding wheel or the work in the width direction of the groove within the finished width of the groove. A groove is formed in the workpiece by grinding.
The invention of claim 2 is characterized in that the grinding wheel is continuously cut.

  According to the grooving grinding method of the present invention configured as described above, the cutting of the rotating grinding wheel is set and the grinding wheel or workpiece is periodically reciprocated in the groove width direction within the finished width of the groove. However, since the workpiece is reciprocated in the groove extending direction to perform grooving grinding on the workpiece, the load applied to the grinding wheel does not increase locally, and the abrasive grains of the grinding wheel Can be prevented from being worn or dropped. Thereby, the thickness (grinding wheel width) of the grinding wheel can be reduced, the dressing interval of the grinding wheel can be lengthened, and the replacement frequency of the grinding wheel can be reduced.

Moreover, since the reciprocating motion in the groove width direction of the grinding wheel is performed within the finished width of the groove, the processing accuracy of the groove width can be increased.
By continuously cutting the grinding wheel, the grinding time can be shortened and the grooving can be performed at a lower cost than the conventional grooving method shown in FIGS. 7 and 8. It can be performed.

The best mode for carrying out the present invention will be described below with reference to the drawings.
FIG. 1 schematically and schematically shows an example of a surface grinding machine used in an example of an embodiment of a grooving grinding method according to the present invention, where (a) is a front view and (b) is a right side view. FIG.

  As shown in FIGS. 1A and 1B, the surface grinder 1 used in the grooving grinding method of this example can reciprocate in the front-rear direction with respect to the main body 2 in the same manner as a known surface grinder. The front / rear direction moving table 3 provided, the left / right direction moving table 4 provided on the front / rear direction moving table 3 so as to be capable of reciprocating in the left / right direction, and the left / right direction moving table 4 are fixedly set. A chuck 5, a vertically moving member 6 provided on the main body 2 so as to be movable up and down, a grinding wheel 7, a base 8 to which the grinding wheel 7 is fixed so as to be exchangeable, and a grinding stone connected to the base 8 A rotating shaft 9, a grinding wheel rotating motor 10 that rotates the grinding wheel rotating shaft 9, a grinding wheel front / rear direction moving member 11 that is provided on the vertical moving member 6 so as to be movable back and forth and supports the grinding wheel rotating motor 10, Wheel front-rear direction shift And a grinding wheel longitudinal direction movement servo motor 11 'for moving the member 11 in the longitudinal direction.

  The chuck 5 is composed of a fixed chuck member 5a and a movable chuck member 5b, and a workpiece to be subjected to grooving grinding is sandwiched and set between the fixed chuck member 5a and the movable chuck member 5b. It has become. That is, as shown in FIG. 2, for example, four first to fourth workpieces 12, 13, 14, and 15 are sequentially aligned with each other and arranged adjacent to each other, and adjacent to the first workpiece 12. The first dummy 16 is disposed and the second dummy 17 is disposed adjacent to the fourth work 15 and set on the fixed chuck member 5a. Then, by tightening the movable chuck member, the first and second dummy members 16 and 17 clamp the first to fourth workpieces 12, 13, 14, and 15, and the four first to fourth workpieces 12. , 13, 14, 15 and the first and second dummy 16, 17 are fixed to the chuck 5. In this way, by using the first and second dummies 16 and 17 on both sides, the sagging that occurs at the edges of the workpieces on both sides when the top surfaces of the first to fourth workpieces 12, 13, 14, and 15 are finished is first. It is generated in the second dummy 16, 17 and not in the first to fourth workpieces 12, 13, 14, 15.

The grinding wheel 7 is formed in a disk shape having a diameter d ₁ from, for example, diamond or CBN. As shown in FIG. 3, in this grinding wheel 7, the width (thickness) t ₁ of the outer peripheral surface 7a is set slightly smaller than the width W of the groove 18 to be ground. Further, the diameter d ₂ {(d ₁ −d ₂ ) in which the difference between the outer peripheral surface 7 a and the diameter d ₁ of the outer peripheral surface 7 a is larger than twice the depth D of the groove 18 among both side surfaces of the grinding wheel 7. > portions between the circumference of the 2 D}, the thickness of the grinder 7 toward the circumference of the diameter d ₂ from the outer peripheral surface 7a is a back taper surface 7b, 7c for decreasing linearly. By these back taper surfaces 7b and 7c, grinding scraps of the first to fourth workpieces 12, 13, 14, and 15 at the time of grinding are discharged from the groove 18 being processed to facilitate the grinding. The back taper dressing of the grinding wheel 7 is performed after the grinding wheel 7 is fixed to the base 8 of the surface grinding machine 1. The edge of the outer peripheral surface 7a of the grinding wheel 7 is an R portion.

  Then, the front / rear position of the grinding wheel 7 relative to the workpiece is set (positioned) by driving the grinding wheel front / rear direction moving servo motor 11 'to move the grinding wheel front / rear direction moving member 11 in the front / rear direction, and the vertical direction moving member 6 Is used to set the cutting amount of the grinding wheel 7 with respect to the workpiece. Next, after the grindstone rotating motor 10 is rotationally driven, the first to fourth workpieces 12, 13, 14, 15 and the first and second dummies 16, 17 are moved by the horizontal movement table 4 as shown in FIG. It is moved in the left-right direction, that is, in the extending direction of the groove 18. Thus, the grooving grinding process by the grinding wheel 7 is performed on the first to fourth workpieces 12, 13, 14, 15 and the first and second dummy 16, 17.

Next, the grooving grinding method of this example in the embodiment of the present invention will be described.
As shown in FIG. 5, the grooving grinding method of this example is as follows. First, the first to fourth workpieces 12, 13, 14, 15 and the first and second dummy 16, 17 are surface grinders as described above. It is arranged on the chuck 5 of 1 and fixed. Next, the grinding wheel 7 is moved in the front-rear direction by the driving wheel front-rear direction moving member 11 by driving the front-rear direction moving servo motor 11 ′, and the center C _{1 in} the width direction of the grinding wheel 7 is about to be processed. Align with the center C _{2 of the} groove 18. Then, in the state where the grinding wheel rotating motor 10 is driven to rotate as described above, the grinding wheel 7 is continuously lowered by the up-and-down direction moving member 6, and the first to fourth workpieces 12, 13, 14, 15 and while performing continuous cuts at a predetermined cut speed v ₁ relative to the first and second dummy 16,17, the left-right direction moving table 4 and the first to fourth work 12, 13, 14, 15 first and The second dummy 16, 17 is reciprocated in the left-right direction at a predetermined number of reciprocations (for example, the number of reciprocations in the left-right direction for 1 minute) n ₁ , and grinding of the groove 18 by the grinding wheel 7 is started. At this time, the grinding wheel 7 is equal to the width C of the groove 18 (front-rear direction of the surface grinding machine 1) α with respect to the center C ₁ of the grinding wheel 7, that is, the predetermined finish width W of the groove 18 and the grinding wheel 7. The number of reciprocations (for example, 1 minute) is controlled by driving and controlling the grinding wheel longitudinal movement servomotor 11 'by a half {(W−t ₁ ) / 2} of the difference from the width t ₁ of the outer peripheral surface 7a. The number of reciprocations in the groove width direction) is periodically reciprocated in the groove width direction, that is, the front-rear direction at n ₂ .

  In this manner, the grinding wheel 7 is rotated and grooved while the grinding wheel 7 is continuously cut into the first to fourth workpieces 12, 13, 14, 15 and the first and second dummy 16, 17. The first to fourth workpieces 12, 13, 14, 15 and the first and second dummies 16, 16 are moved by the horizontal movement table 4 while being reciprocated periodically within the finishing width W of the groove 18 in the width direction 18. The groove 18 is ground by the grinding wheel 7 by reciprocating 17 in the left-right direction. The same grinding process is continuously performed until the cut amount reaches the finishing depth D of the groove. Thus, one groove 18 having a predetermined finishing width W and a predetermined depth D is formed in each of the first to fourth workpieces 12, 13, 14, 15 and the first and second dummy 16, 17 in one step. The

Next, adjacent to the formed groove 18, the groove machining position of the first to fourth workpieces 12, 13, 14, 15 (position of the next groove 18 in the width direction center C ₂ ) is the same as described above. The grinding wheel 7 is set so that the center C ₁ in the width direction of the grinding wheel 7 coincides. In the same manner as described above, the groove 18 is ground by the grinding wheel 7, and the first to fourth workpieces 12, 13, 14, 15 and the first and second dummy 16, 17 are each provided with a predetermined finishing width W and A second groove 18 having a predetermined depth D is formed. Thereafter, by repeating the same grinding process with the grinding wheel 7, four punching dies in which a predetermined number of grooves 18 are formed in a comb blade shape on the first to fourth workpieces 12, 13, 14, 15 are obtained. It is formed. At this time, there is a possibility that the edge of the first and second dummies 16 and 17 may sag, but this sag does not occur in the first to fourth workpieces 12, 13, 14 and 15, and high quality punching is performed. A mold is formed.

According to the grooving grinding method of this example, the workpiece is transferred to the left and right sides of the surface grinder 1 while continuously cutting the rotating grinding wheel 7 and periodically reciprocating the grinding wheel 7 in the groove width direction. Since the workpiece is subjected to grooving grinding by reciprocating in the direction perpendicular to the groove width direction, the load applied to the grinding wheel 7 does not increase locally. Abrasion or falling off of abrasive grains can be suppressed. Thus, it is possible to reduce the grinding wheel thickness (grindstone width) t _1, it is possible to increase the interval of dressing the grinding wheel 7, it is possible to reduce the frequency of replacement of the grinding wheel 7.

In addition, since the grinding wheel 7 is moved within the finishing width of the groove 18 to form a periodic reciprocation in the groove width direction, the processing accuracy of the groove width can be increased.
Further, by continuously cutting the grinding wheel 7, the grinding time can be shortened and the cost can be reduced as compared with the conventional groove forming method shown in FIGS. 7 and 8. Grooving can be performed.

  In the above-described example, the grooving grinding method for forming a large number of grooves 18 provided in a comb-blade shape is described, but the present invention is not limited to this, and one or more grooving grinding methods are described. The present invention can also be applied to a grooving grinding method for forming an arbitrary number of grooves 18. However, in order to obtain the above-described effects of the present invention remarkably, it is preferable to apply the grooving grinding method of the present invention to the grooving grinding of a large number of grooves 18 provided in a comb blade shape. .

  In the above example, the grinding wheel 7 is periodically reciprocated in the groove width direction. However, the grooving grinding method of the present invention does not reciprocate the grinding wheel 7 in the groove width direction. Can be reciprocated periodically in the groove width direction.

Next, a specific example of the grooving grinding method of the present invention will be described.
1. About grinding wheel 7 (1) Outer diameter d ₁ : φ150
(2) Whetstone: Diamond (3) Abrasive grain: # 600
(4) Thickness (width) t _{1 of the} outer peripheral surface 7a: 0.28 m
(5) R part of edge of outer peripheral surface 7a: 0.1 mm
(6) Diameter d ₂ : φ139
(7) Thickness (width) t ₂ : 0.27 mm
2. Workpieces (1) Workpiece and dummy material: Carbide (2) Workpiece thickness: 1.5mm
(3) Dummy plate thickness: 1.0mm
(4) Number of workpieces: 4 (5) Number of dummy: 2 (6) Groove width W: 0.30 mm
(7) Groove depth D: 4.0 mm
(8) Width of comb blade between grooves: 0.2 mm
(9) Number of grooves: 20
(10) Overall length in workpiece groove direction: 10.2 mm
3. Grinding conditions (1) Number of revolutions of grinding wheel: 3600 rpm
(2) Peripheral speed of grinding wheel: about 1700 m / min
(3) Number of reciprocations of workpiece in the left-right direction n ₁ : 500 reciprocations / min
(4) Continuous cutting speed v ₁ (Wheel cutting depth per minute): 0.5 mm / min
(5) Number of reciprocations in the groove width direction (front-rear direction) of the workpiece n ₂ : 500 reciprocations / min
_{(6) (W-t 1} ) /2:0.01mm
4. About grinding time Total grinding time T: T = t1 + t2 + t3≈200 min
Total groove grinding time t1: (groove depth x number of grooves) / grinding wheel cutting amount per minute
= (4.0 × 20) /0.5=160min
Non-grinding time t2: Time required other than actual grinding such as movement of the grinding wheel to the workpiece
= 0.5 mm x 20 per groove = 10 min
Measurement / whetstone dressing time t3: about 10 min
5. Comparison of grinding time by the grinding method of the present invention and grinding time by the conventional grinding method (1) Grooving grinding time by the conventional grooving grinding method shown in FIG. 7 Grooving grinding method shown in FIG. (A) The grinding wheel and workpiece are the same as those of the above-described specific example 1. Grinding wheel and workpiece of the present invention, respectively.
(B) Under grinding conditions, the number of revolutions of the grinding wheel, the peripheral speed of the grinding wheel, and the number of reciprocations of the workpiece in the left-right direction are the same as those in the above-described specific examples of the present invention 3. (1) to (3) .
In general, the normal cut size is set to 1 μm for each return end on one side for one reciprocation of the left and right tables 4. Therefore, the continuous cutting speed v ₁ (the grinding wheel cutting amount per minute): 1 μmm / sec. Therefore, the total grooving grinding time by the conventional grooving grinding method shown in FIG.
Grooving time by conventional grooving grinding method
= (4.0 × 20) /0.001=1333 min
Therefore, the grinding time is 160/1333 = 1 / 8.3. According to the grooving grinding method of the present invention, the grinding time is about 1/8 of the conventional grooving grinding method shown in FIG. Only shortened.
6. Accuracy of grinding pitch etc. The groove widths formed by the grinding method of the present invention all cleared the groove width accuracy of 0.3 ± 0.01 mm. The pitch between the groove and the next groove cleared the pitch accuracy of 0.5 ± 0.002 mm. Therefore, it was found that high machining accuracy of the groove 18 can be obtained.

  The grooving grinding method of the present invention is for punching having a groove such as a punching die having a number of grooves used in a comb blade shape, for example, for punching a lead frame for mounting a semiconductor chip by pressing. It can be suitably used for grinding a mold.

BRIEF DESCRIPTION OF THE DRAWINGS An example of the surface grinder used for an example of embodiment of the grooving grinding method which concerns on this invention is shown typically and schematically, (a) is a front view, (b) is a right view. It is a figure which shows an example of the set to the surface grinder in the grooving grinding method of this example. It is a figure explaining the grinding wheel used for the grooving grinding method of this example. It is a figure explaining the movement of the workpiece | work at the time of grinding by the grooving grinding method of this example. It is a figure explaining the grooving grinding method of this example. It is a figure which shows an example of the processed material which has the comb-tooth shaped groove | channel formed by the conventional grooving grinding method. It is a figure explaining an example of the conventional grooving grinding method. It is a figure explaining the other example of the conventional grooving grinding method.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Surface grinder, 2 ... Main body, 3 ... Front / rear direction moving table, 4 ... Left / right direction moving table, 5 ... Chuck, 6 ... Vertical moving member, 7 ... Grinding wheel, 8 ... Base metal, 9 ... Grinding wheel rotation axis DESCRIPTION OF SYMBOLS 10 ... Grinding wheel rotation motor, 11 ... Grinding wheel longitudinal movement member, 11 '... Grinding wheel longitudinal movement servo motor, 12, 13, 14, 15 ... 1st thru | or 4th workpiece | work, 18 ... Groove

Claims (2)

A groove is formed in the workpiece by setting a cutting depth of the grinding wheel to the workpiece and reciprocating in the extending direction of the groove forming the workpiece while rotating the grinding wheel. In the grinding method,
A groove is formed in the workpiece by grinding the workpiece while the grinding wheel or the workpiece is periodically reciprocated in the width direction of the groove within the finished width of the groove. Grooving grinding method. The grooving grinding method according to claim 1, wherein the grinding wheel is continuously cut.

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