Boring apparatus for a laminated plate and boring cutter

Abstract: An apparatus for boring a laminated plate includes a table having a first surface on which a laminated plate may be placed for boring and an opposing second surface, the table defining at least one passage therethrough; a supporting pad for urging a laminated plate to be bored towards the first surface of the table; and a cutter for boring a laminated plate to be bored, the cutter operable to bore in a direction generally opposite to the direction that the supporting pad urges and through the passage defined by the table. Further according to the present invention, the cutter includes a knife edge, a pivotal mechanism adapted to be pivoted about its axial center line, and a stepping mechanism (5) for moving the knife edge in one direction and unsuccessively further in a second direction so that successively deeper boring may be performed. Also according to the present invention, a boring cutter having an axial center line about which the cutter is operable to be rotated includes a cutting element having a modified round-bar shape. Still further, according to the present invention, a method of boring a multi-layer laminated plate includes the steps of pressing against the plate in one direction; and boring the the plate in a direction opposite to the direction in which it is pressed, the boring characterized in that a boring element is withdrawn between boring of each individual layer of the multi-layer plate.

Description: Field of the Invention The present invention relates to a boring apparatus for laminated plates and, more particularly, to a boring apparatus that is especially suitable for boring multi-layer plates. Description of the Prior Art A multi-layered substrate has been recently employed to form an electronic circuit within a limited area and volume. To produce a multi-layered substrate, a prepreg (i.e., an insulating material in which two surfaces with spun glass fibers woven thereon are coated with uncured epoxy resin) is sandwiched between substrates and then subjected to pressing and heating. To accurately position the prepreg with respect to the substrates, it is necessary to bore holes in the prepreg, in advance, with the holes being adapted for receiving reference pins. Prepregs are normally bored in a multi-layer, packaged form to prevent contamination which leads to defective energization. In addition, copper foils are coated on upper and lower surfaces of the multi-layered substrate, and these copper foils also need be bored in advance. Thin plates which need to be bored in advance, other than the prepreg and copper foils described above, are increasingly being used in a number of technical fields. Therefore, a need has arisen for development of means capable of accurately boring holes in such materials. One heretofore known means for boring thin plates such as prepregs, copper foils and the like, is press means. Press means involves placing plates, one by one, on a press, and then punching the plates with a die. This poses a problem in that the efficiency of boring work is low, resulting in contamination of both sides of the plate. Another problem, especially for the aforesaid prepreg, is that a package needs to be unpacked to prevent contamination. Another conventional boring means is drilling means (see for example US-A-3051205). The use of drilling means involves placing plates in a laminated fashion on a drilling machine and cutting and boring them by means of a drill having a spiral groove or the like. This has an advantage in that the efficiency of boring work is good and less contamination in plates occurs, at least as compared with the aforementioned press means. However, a separate problem is created, in terms of work accuracy, in that the plates become fused together due to frictional heat between the drill and the plate, and chips thereby become fused around bored holes. Particularly, since the copper foil is pliable in nature, there is a problem in that distortion or burrs occur around a bored hole. A further problem is that since chips or the like are scattered due to the rotation of a drill or the like, maintenance of the drilling apparatus, especially cleaning, is time-consuming. Chips not cleaned away can adhere to parts of the drilling apparatus and lessen the durability thereof. SUMMARY OF THE INVENTION The present invention has been developed in order to solve the aforementioned problems. It is an object of the present invention to provide an apparatus for boring a laminated plate that can bore a thin plate with high accuracy, which is easy to maintain, and which has good durability. It is another object of the present invention to provide a boring cutter having these same characteristics. The problem is solved by an apparatus for boring a laminated plate according to claim 1. In the aforementioned structure, the cutter bores a laminated plate so as to circularly cut off portions with the knife edge. The cutter, the pivotal mechanism and the stepping mechanism operate in unison to minimize chip occurrence, to perform boring naturally and accurately, to facilitate chip removal, and to prevent occurrence of distortion and burrs around holes and fusion of chips and cut pieces. Thus, boring precision is increased. Moreover, the cutter is preferably formed with an air path for discharging air toward the tip of the knife edge thereof. The air path of the cutter has, as its object, the discharge of air towards a bored portion, to assist in removing the chips and cut pieces, and to cool the bored portion to prevent the deposition of the plates with each other and the like so as to enhance the boring accuracy. Furthermore, preferably, an accommodating chamber is provided around the cutter at the lower side of the work window, and a vacuum mechanism is attached to the accommodating chamber. The accommodating chamber is designed to accommodate the removed chips and the like therein, and the vacuum mechanism is designed to discharge the chips and the like outside the apparatus, to prevent the chips and the like from adhering to various parts of the apparatus, and to facilitate maintenance so as to improve durability. Of course, the first surface may be an upper surface, the second surface may be a lower surface, the supporting pad may press generally downward, and the cutter may bore generally upward. The knife edge may have an obliquely-cut round-bar shape, a concave cutting surface, or portions defining an air passage therethrough. In the latter case, assuming that the knife edge has a cutting point, the air path may have a discharge opening in the vicinity of that cutting point. Still further, according to the present invention, the supporting pad may have portions defining an air passage therethrough. In such case, the air passage through the supporting pad may have a discharge opening located so that discharged air may impinge on a laminated plate. According to the present invention, the invention concerns also a boring cutter according to claim 27, and a method of boring a multi-layer laminated plate according to claim 31. The means for rotating the cutting element about its axial center line may include a motor (e.g., an air motor) having a rotating output shaft. In such a case, an apparatus according to the present invention would likely also include means for connecting the cutting element and the rotating output shaft of the air motor. This means for connecting the cutting element and the rotating output shaft of the air motor may have an air passage therethrough. The means for rotating the cutting element about its axial center line may include an air motor having a rotating output shaft and means for connecting the cutting element and the rotating output shaft of the air motor may also be present. In addition, an apparatus according to the present invention may also include means for connecting the air motor to the stepping The cutting element, air motor, and stepping mechanism may all be disposed in a unit box and an apparatus according to the present invention may include means for moving that unit box, e.g., a threaded bar. An apparatus according to the present invention may also include means for controlling operation of the supporting pad and cutter so that those elements operated in unison. This means may include a CPU. Such a CPU may also control movement of a unit box. Dependent claims illustrate preferred embodiments of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS The above and other objects, features and advantages of the present invention will be described hereinafter with respect to the accompanying drawings, in which, like reference numerals represent similar parts throughout and wherein: Fig. 1 is a sectional view showing an embodiment of an apparatus for boring a laminated plate according to the present invention; Fig. 2 is a sectional view showing the initial stage of operation of the apparatus of Fig. 1; Figs. 3 and 4 are, respectively, enlarged views showing essential steps of the operation subsequent to that shown in Fig. 2; Fig. 5 is a sectional view showing the completion state of operation of the apparatus; Fig. 6 is a front view of the entire apparatus, including respective portions of the apparatus used for boring a laminated plate according to the present invention; and Figs. 7 to 9 are sectional views showing modified forms of the cutter. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an apparatus for boring a laminated plate according to the present invention will be described hereinafter with reference to the accompanying drawings. In this embodiment, the apparatus comprises, as shown in Fig. 1, a table 1, a supporting pad head 2, a cutter 3 and an accommodating chamber c, the cutter 3 having a (pivotal) drive mechanism 4 and a stepping mechanism 5 attached thereto, the accommodating chamber c having a vacuum mechanism 8 attached thereto. Table 1 comprises a sliding table section 11 and work table section 12. Referring now also to Fig. 6, sliding table section 11 is movably provided on a machine body B through a moving mechanism 13, the moving mechanism 13 including a threaded bar or the like which is capable of moving the sliding table section 11 in a lateral direction (i.e. toward 5 and away from a viewer of the drawing). The work table section 12 is secured to the sliding table section 11. Sliding table section 11 has a funnel-like work passage 14 passing therethrough in a predetermined location. The supporting pad head 2 is provided to press and support the laminated plate A towards the table 1 (work table section 12) from above the work passage 14, and comprises an air cylinder 21, a rod 22 connected to the air cylinder 21 and a cushion material pad 23 secured to the extreme end of the rod 22. The air cylinder 21 applies a pressing force towards and on the laminated plate A through the rod 22 and the cushion pad 23. Cushion pad 23 forms a buffer by which the surface of the laminated plate A is prevented from being damaged by the pressing force. The rod 22 and cushion pad 23 are interiorly provided with an air path 24 in communication with the air cylinder 21 so that air can be discharged from the air cylinder 21 towards the laminated plate A. The supporting pad head 2 is carried by the machine body B through a moving mechanism 25, which is formed from a threaded bar or the like and may be similar to the moving mechanism 13 of the table 1. Mechanism 25 is capable of moving the supporting pad head 2 in a lateral direction indicated by double-headed arrow X in Fig. 6. Cutter 3 performs the boring work for the laminated plate A from the underside of the work passage 14 and comprises a cutting edge 31 produced by cutting a round bar in a direction obliquely to the axis thereof and by making the cut surface at least partially concave. The cutter also comprises an air path 32 bored from the extreme end of the cutting edge 31 towards a shank portion of the cutter. A nut 34 formed with a communication passage 33 internally therearound is fitted around the body portion of the cutter 3 so that the cutter can rotate therein and a tube 35 connected to an air pump (not shown) is connected to the nut 34 so that air may supplied via tube 35 to the passage 33 and path 32 to be discharged from the extreme end of the knife edge 31. This nut 34 is secured by means of a pin 36 to the drive mechanism 4 which will be described later. The drive mechanism 4 rotates the cutter 3 so that it rotates around the axial center line thereof of the drive mechanism. The drive mechanism 4 comprises an air motor. The air motor is interiorly provided with a blade (not shown) secured to a rotational shaft (not shown) so that the blade and the rotational shaft may be rotated by air, which is supplied from an air opening 41 and discharged from a discharge opening 42. The cutter 3 is secured to a mounting chuck 43 connected to the rotational shaft. The stepping mechanism 5 causes the cutter 3 including the dirve mechanism 4 to be moved upwards and downwards and comprises a pulse motor connected to the drive mechanism 4. The pulse motor is controlled in its operating range or the like by a controller 6. The operating mode for temporarily moving down the cutter 3 between each of a series of boring operations by the cutter 3 is set by the controller 6. Controller 6 may be a CPU. The accommodating chamber c provided around the cutter 3 to the underside of the work passage 14 is defined by the upper portion of a lift frame 73, which will be describe later. The cutter 3, the drive mechanism 4, the stepping mechanism 5 and the accommodating chamber c are disposed or accommodated within a unit box 7, which is provided on the machine body B through a moving mechanism 71 formed from a threaded bar or the like similar to the aforesaid moving mechanisms 13 and 25. The moving mechanism 71 causes the unit box 7 to be moved in a direction as indicated by double-headed arrow X', and is interlocked with the moving mechanism 25 of the supporting pad head 2 by the controller 6. The unit box 7 is provided, in addition to the moving mechanism 71, with a housing 72, the lift frame 73 and an air cylinder 74. The housing 72 is formed from a hollow body constituting an outer portion of the unit box 7 and interiorly provided with a guide 72a for upward and downward movement of the drive mechanism 4, a fixing bed 72b and a guide 72c for the stepping mechanism 5, a guide 72d for upward and downward movement of the lift frame 73 as described further below. The lift frame 73 is provided so that it may be moved upwards and downwards within the housing 72, and a contact portion 73a which contacts the lower surface of the work table 12 to encircle the work passage 14 is mounted on the upper portion of the lift frame 73, said contact portion 73a includes a tube 73b mounted thereon so as to surround the cutter 3 and the upper portions of the drive mechanism 4. The contact portion 73a and the tube 73b constitute the aforesaid accommodating chamber c. A seal 9 is interposed between the tube 73b and drive mechanism 4 in order to improve the sealing performance. The air cylinder 74 is secured to the bottom of the housing 72 by means of a fixing bolt 72e and comprises a means for moving the lift from 73 upward and downward. The vacuum mechanism 8 comprises a tube 81 connected to the accommodating chamber c and extend from the unit box 7, to a vacuum pump 82 which includes an accumulator and a filter connected to the tube 81 outside the machine body B. The interior of the accommodating chamber c is vacated by the suction force of the vacuum pump 82 through the tube 81. In operation of an embodiment constructed as described above, during boring operation, the laminated plate A is first placed on the upper surface of the work table section 12. In the case of a prepreg packaged as mentioned above, it is placed without unpacking. After the laminated plate A has been so placed, the moving mechanisms 25 and 71 are operated by the control of the controller 6 whereby the supporting pad head 2 and the cutter 3 (the unit box 7) are positioned on the center line of the work passage 14 of the work table 12 as shown in Fig. 1. The boring work starts from the state shown in Fig. 1 as mentioned above. As shown in Fig. 2, first, the air cylinder 74 within the unit box 7 is actuatd to move the lift frame 73 upwards to bring the contact portion 73a of the lift frame 73 into contact with the lower surface of the work table 12, and the accommodating chamber c defined by the contact portion 73a and tube 73b is completely sealed by the lower surface of the work table 12. Thereafter, the drive mechanism 4 is actuated to turn the cutter 3, and the stepping mechanism 5 is actuated to move the cutter 3 upward. The cutter 3 is rotated as shown in Fig. 3 to bore only the lowermost layer, the plate Aa, of the laminated plate A producing a plate or coupon Aa''. At the same time air, is supplied through tube 35 and discharges through the cutter 3 into chamber c. After termination of the boring of the lowermost layer plate Aa, the stepping mechanism 5 is actuated to move the cutter 3 down as shown in Fig. 4. After the temporary downward movement of the cutter 3, the stepping mechanism 5 is further actuated to move the cutter 3 upwards to bore the next layer, the plate Ab. It must be moved up by an amount equal to the extent it was moved down in the temporary downward movement of the cutter plus the thickness of the next layer Ab. In this way, the entire laminated plate A is bored. In this boring step, the operation of the stepping mechanism 5 or the like is controlled by the controller 6. The operation of the stepping mechanism 5 may also be set to the controller 6 so that two or several plates Aa and Ab may be bored at each upwards movement of the cutter depending upon the material of the laminated plate A or the like. When the boring work in conjunction with a single work passage 14 is terminated as described above, the lift frame 73 is moved down, and the elements reposition themselves (as shown in Fig. 1) around another work passage 14 by movement of the supporting pad head 2 and the cutter 3 (unit box 7) in the X direction caused by the moving mechanisms 27 and 71, and by movement of the sliding table section 11 (work table section 12) in the lateral direction (i.e. toward or away from a viewer) caused by the moving mechanism 13. It is noted that the movement thereof to another work passage 14 is also controlled by the controller 6. In the aforementioned boring work, the plate "Aa" of the laminated plate A is bored so as to cut it off by the knife edge 31 due to a distinctive feature of the cutter 3 and the rotation thereof. Therefore, stress of a cutting force of the knife edge 31 of the cutter 3 is not deflected and concentrated around a hole Aa' to be bored; even if material of the laminated plate A is pliable like said copper foil, distortion or burr will not occur around the hole Aa; and occurrence of chips is minimized. In the case of the aforementioned package prepreg, a package material becomes bored at the same time in boring the lowermost layer plate Aa. Furthermore, since the boring work is carried out from the lower side of the laminated plate A, cut pieces Aa'' and chips caused by boring fall due to their own weight and are naturally removed. In the removal of the cut pieces Aa'' and chips, air discharged from the extreme end of the knife edge 31 of the cutter 3 performs wiping cleaning in assisting the removal while preventing adhesion of the cut pieces Aa'' and chips to and around the hole Aa'. When boring is terminated as shown in Fig. 5, air discharged from the air path 24 of the supporting pad head 2 flows into the hole Aa'. Therefore, the wiping cleaning to and around the hole Aa' is carried out also by this air. Moreover, downward movement of the cutter 3 between each of a series of boring operations prevents the cut piece Aa'' from being sandwiched between the cutter 3 and the hole Aa'. The thus removed cut pieces Aa'' and chips are received into the accommodating chamber C, pass through the tube 81 and are discharged outside by the suction of the vacuum pump 82. Therefore, they are prevented from being scattered and from adhering to various parts of the apparatus. Moreover, the air discharged from the extreme end of the knife edge 31 of the cutter 3 cools around the hole Aa' to prevent fusion of the chips around the hole Aa' and fusion of the plates Aa and Ab. This fusion prevention can be enhanced by changing air into cool air by means of a heat exchanger or the like. Air discharged from the supporting pad head 2 also assists this cooling. Other than the above-described embodiments, other actuators may be employed for the drive mechanism 4, the stepping mechanism 5 and the like. In addition, in case of small-scale boring, manual control in place of control by the controller 6 may be employed. Figs. 7 to 9 show modified forms of the aforementioned cutter 3. Fig. 7 shows a construction in which a cutter 3a is not provided with the air path 32 as is the cutter 3; Fig. 8 shows a construction in which a cutter 3b has a cutting surface of a knife edge 31' in the form of an inclined flat surface instead of a partially concave surface; and Fig. 9 shows a construction in which a cutter 3c is formed with an air path 32' in the knife edge 31' of the cutter 3b. It is to be noted that in the present invention, not only the aforesaid cutters 3, 3a, 3b and 3c, but also modified forms thereof can be used. As described above, in the apparatus for boring a laminated plate according to the present invention, the fusion of chips and fusion of the laminated plate itself are prevented and, in addition, occurrence of distortion and burrs is prevented. Thus, the present invention operates to bore laminated plates with excellent accuracy. Moreover, since chips or the like are not scattered and/or allowed to adhere to various parts of the apparatus, maintenance, i.e. cleaning, is easily accomplished and excellent durability is obtained. Clearly, numerous modifications and variations are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims, the invention may be practised otherwise than as specifically described.

Claims: An apparatus for boring a laminated plate comprising a plurality of layers, said apparatus comprising: (a) a table (1) having a first surface on which a laminated plate (A) may be placed for boring and an opposing second surface, said table defining at least one passage (14) therethrough; (b) a supporting pad (2) for urging a laminated plate A to be bored towards the first surface of said table (1); and (c) a rotatable cutter (3) for boring the laminated plate (A); and (d) a rotatable drive mechanism (4) for rotating the cutter (3), characterised in that said cutter (3) comprises a cutting edge (31) offset relative to the axis of rotation of the cutter (3) whereby the cutter (3) cuts the layers of the laminate plate (A) along a circular cut line, and the apparatus includes a stepping means (5) connected to move the cutter sequentially towards and away from the laminate plate (A) so that cut portions of layers can be removed before subsequent layers are cut. An apparatus as recited in claim 1, characterised in that the first surface is an upper surface, the second surface is a lower surface, the supporting pad head (2) presses generally downward, and the cutter (3) bores generally upward. An apparatus as recited in claim 2, characterised in that said cutter (3) has an obliquely-cut round-bar shape. An apparatus as recited in claim 2, characterised in that said cutter (3) has a concave cutting edge (31). An apparatus as recited in claim 2, characterized in that said cutting edge (31) has portions defining an air passage (32) therethrough. An apparatus as recited in claim 5, characterized in that said cutting edge (31) has a cutting point and the air path (32) has a discharge opening in the vicinity of the cutting point of the cutting edge (31). An apparatus as recited in claim 2, characterised in that said supporting pad head (2) has portions defining an air passage (24) therethrough. An apparatus as recited in claim 7, characterised in that said air passage (24) through said supporting pad has a discharge opening located so that discharged air may impinge on the laminated plate (A). Apparatus for boring a laminated plate according to claim 1 characterised in that the apparatus further comprises (a) elements defining an accommodating chamber (c) for chips and the like, the accommodating chamber (c) being located on the cutter side of the work passage (14); and (b) a vacuum mechanism (8) attached to the accommodating chamber (c). An apparatus as recited in claim 9, characterised in that the first surface is an upper surface, the second surface is a lower surface, the supporting pad head (2) presses generally downward, and the cutter bores generally upward. An apparatus for boring a laminated plate as in claim 1 characterized in that the cutter (3) comprises a cutting edge (31) and the cutter (3) is adapted to be rotated about its axial center line, said cutter 3 further adapted to be moved in both directions along its axial center line. An apparatus as recited in claim 11 wherein said means for rotating said cutter (3) about its axial center line comprises a motor having a rotating output shaft. An apparatus as recited in claim 12 wherein said motor having a rotating output shaft comprises an air motor having a rotating output shaft. An apparatus as recited in claim 13 further comprising means for connecting the cutter (3) and the rotating output shaft of the air motor. An apparatus as recited in claim 14 wherein said means for connecting the cutter (3) and the rotating output shaft of the air motor has an air passage therethrough. An apparatus as recited in claim 11 wherein said means for moving said cutter (3) in both directions along its axial center line comprises a stepping mechanism (5). An apparatus as recited in claim 16 wherein said means for rotating said cutter (3) about its axial center line comprises an air motor having a rotating output shaft. An apparatus as recited in claim 17 further comprising means for connecting the cutter (3) and the rotating output shaft of the air motor. An apparatus as recited in claim 18 characterised by means for connecting the air motor to the stepping mechanism (5). An apparatus as recited in claim 19 characterised by a unit box (7) in which the cutter (3), air motor, and stepping mechanism are disposed. An apparatus as recited in claim 20 characterised in that the apparatus further comprises means (71) for moving said unit box (7). An apparatus as recited in claim 21 characterised in that said means (7) for moving said unit box (7) comprises a threaded bar. An apparatus as recited in claim 22 characterised in that the apparatus further comprises means for controlling operation of the means for urging and the cutter (3) so that those elements operate in unison. An apparatus as recited in claim 23 characterised in that said means for controlling comprises a CPU. An apparatus as recited in claim 24 characterised in that said CPU further controls movement of the unit box (7). An apparatus for boring a laminated plate (A) as in claim 1 characterised in that said cutter is adapted to be moved about its axial line and in both directions along its axial centre line and, further comprises (d) elements defining an accommodating chamber for chips and the like; and (e) a vacuum mechanism attached to the accommodating chamber. A boring cutter (3) with a modified round-bar shape and characterised in that the cutter (3) has an obliquely-cut round-bar shape and the cutter (3) has portions defining an air passageway (32) therethrough. The boring cutter (3) of claim 27 characterised in that the cutting edge (31) has a substantially concave cutting edge. The boring cutter of claim 28 characterised in that the cutter (3) has a pointed end. The boring cutter of claim 29 characterised in that the air passageway (32) through the cutter element has a discharge opening in the vicinity of the pointed end. A method of boring a multi-layered laminated plate (A) comprising the steps of: pressing against the plate (A) in one direction; and boring the plate (A) in a direction generally opposite to the direction in which it is pressed, said boring characterised in that a cutter element (3) is withdrawn between boring of each individual layer, or group of layers, of the multi-layer plate (A). A method as recited in claim 31 characterised by the further step of: blowing air towards the laminated plate (A) in the direction in which it is bored. A method as recited in claim 32, wherein the blown air passes through the cutter element (3). A method as recited in claim 31 further characterised by the step of blowing air toward said laminated plate (A) in a direction in which it is pressed. A method as recited in claim 31 characterised by the further step of vacuuming away bored portions (Aa) of the laminated plate (A).

Inventors: KAKIMOTO MASAKAZU, KAKIMOTO, MASAKAZU, KAKIMOTO, MASAKAZU C/O USHIO CO. LIMITED
Applicants: USHIO KK, USHIO CO. LIMITED
Application year: 1988
Main classification: B26F1
IPC codes: B26D7, B26F1, H05K3