APPARATUS FOR THE AUTOMATIC SEPARATION ALONG PREDETERMINED BENDING FRACTURE LINES IN BASIC CERAMIC PLATELETS OF HYBRID ELECTRONIC CIRCUITS

Abstract: Apparatus for the automatic separation, along predetermined bending fracture lines, in basic ceramic platelets of hybrid electronic circuits, which apparatus comprises a support plate, provided with grooves on its lower face extending into close proximity with its upper face, these grooves defining bending lines, disposed in correspondence with the bending fracture lines of a ceramic platelet placed in register above said plate, which grooves define relative bays of the plate which are rigid in bending, these bays corres­ ponding to the single elements into which the platelet is to be subdivided, upper pressing members being present adapted for clamping each element of the platelet against the corresponding bay or square of the plate, which is rigidly supported in correspondence with one single bay or square, lower opposing members being present, acting against each of the remaining bays, these members being retractable on command in a predetermined sequence, the successive bending of the plate along the lines defined by the grooves of said plate being brought about by the action of the upper pressing members, said bending causing the fracture of the ceramic platelet along the predetermined lines coinciding with the grooves of the plate.

Description: The subject of the present invention is an apparatus for the automatic separation, along predetermined bending fracture lines, in basic ceramic platelets of hybrid electronic circuits. For the construction of electronic apparatuses of various types, electronic circuits known as "hybrid" circuits are used, which are composed of a platelet of ceramic material or the like, on which some components of the circuit and the relevant connections are formed by various techniques, while other components are applied above said circuit. Such circuits are usually constructed on basic platelets of relatively large dimensions, on which several single circuits are formed arranged in several parallel rows; at the end of the processing, the single elements corresponding to each circuit are separated along the relevant boundary lines, by bending in correspondence with incisions into the thickness of the platelet which are predetermined for this purpose. Such operations may be carried out by hand or by means of simple devices, which clamp an element and bend the adjacent element, but in these cases it is possible that the fracture may not take place along the predetermined lines but, as a result of anisotropy of the material and, in particular, as a result of lack of support at a rigid, straight abutment of the elements of the platelet in proximity to the fracture line, the fracture may move away from this line, thus resulting in scrapping or rejection of already completed pieces. Such a circumstance is particularly harmful because the pieces to be rejected have reached the end of processing and carry components which in some cases are particularly expensive. From US 3 206 088 it is known a method to obtain division of semiconductor plates into smaller bodies such semiconductor plates which are nevertheless flat plates without electronic components welded on them, while quite different problems arise when the separation must be effected on base plate already carrying electronic components. The requirement therefore arises for providing an apparatus which shall make possible the separating of the elements of the ceramic platelets of circuits in an automatic manner and with the certainty of not causing damage to the pieces themselves, by producing the fractures exactly along the incision lines intended for this purpose. Said results are achieved by the present invention, which provides an apparatus for the automatic separation along predetermined bending fracture lines in basic ceramic platelets of hybrid electronic circuits, which apparatus comprises a support plate, provided on its lower face with grooves extending into close proximity with its upper face, these grooves defining bending lines and being arranged in correspondence with the bending fracture lines of a ceramic platelet placed in register on said plate, which grooves define relative bays or squares of the plate, which are rigid in bending, corresponding to the single elements into which the platelet is to be subdivided, there being also present upper pressing members adapted for clamping each element of the platelet against the corresponding bay of the plate, which plate is rigidly supported in correspondence with one single bay, there being also present lower opposing members acting against each of the remaining bays, these members being retractable on command in a predetermined sequence, the successive bending of the plate along the lines defined by the grooves of said plate being determined under the action of the upper pressing members, said bending causing the fracture of the ceramic platelet along the predetermined lines coinciding with the grooves of the plate. The support plate may be composed of a plate of plastics material of large thickness, provided with notches defining flexible diaphragms in the material itself along the predetermined bending lines for the plate or, alternatively, the support plate may be composed of a flexible thin sheet, underneath which there are rigidly attached the bays or squares, made of a material rigid in bending, separated from one another by grooves corresponding to the intended bending lines of the plate. The upper pressing members are composed of thrust members carried by a common frame, the frame being movable by a relative actuator means between a position of engagement of the pressing members with the platelet and a position remote from said platelet. The pressing members advantageously each comprise an elastic pressure element and a controllable retraction actuator. The grooves of the lower surface of the plate are composed basically of inverted V-section notches, having their apex in proximity to the upper face of said plate. The lower opposing members acting against the free bays of the plate are composed of actuators controllable according to a predetermined sequence by a programmable control unit; alternatively, the lower opposing members acting against the free bays of the plate are composed of cams having one or more lobes and carried by associated parallel shafts, actuated by a single common motor, which cams possess lobes arranged in a mutual angular relationship determining the bending of the bays of the plate along the lines defined by the grooves according to a predetermined sequence. Between the ceramic platelets and the plate there is interposed a thin flexible conveyor belt for conveying the platelets above said plate. The lower opposing members and the upper pressing members may be arranged according to a fixed grid, with a pitch equal to or less than the minimum dimension of the elements of the ceramic platelet and of the corresponding bays of the plate, at least one of the pressing members and of the actuators being in contact respectively with each element of the ceramic platelet and each bay of the plate. Further details will become apparent from the following description, with reference to the attached drawings, in which there are shown: in Figure 1, a schematic perspective view of an apparatus according to this invention in the phase of fracturing a platelet for hybrid circuits; in Figure 2, the apparatus according to this invention in one form of embodiment, in front view; in Figure 3, a section on the plane III-III of Figure 2; in Figure 4, a section on the plane IV-IV of Figure 2; in Figure 5, the apparatus according to this invention in an alternative form of embodiment; in Figure 6, one possible arrangement of successive fractures of a platelet forming several rows of circuits. As Figure 1 shows, the hybrid electronic circuits are produced in several contiguous elements 1a, 1b, 1c and so on, on one single platelet 2 of ceramic material; between one element and the next there is provided a fracture line 3, composed of a localized weakening of the ceramic material of the platelet, produced, for example, by a laser incision of a series of contiguous holes, not passing right through, in the platelet, aligned along the desired line. The bending of the ceramic platelet along the line 3 through an angle α of a few degrees causes breakage of the ceramic material, thereby separating the various circuits produced on said common platelet. The apparatus according to this invention comprises a support plate 4, of plastics material, having an appreciable thickness so as to make it substantially rigid, the plate being provided with grooves 5 incised in its lower face, having a substantially inverted V-section, extending through a major part of the thickness of the plate, so as to leave a thin diaphragm 6 near the upper face of said plate, in correspondence with which a discharge groove 7 is present on the same upper surface. The grooves 5 are disposed along the fracture lines intended for the platelet and define preferential folding lines for the plate 4, resulting from the flexibility of the diaphragm 6. The plate 4 is subdivided by the grooves 5 and by the corresponding discharge grooves 7 into several bays or squares 4a,4b,4c,4d and so on, which correspond to the single elements 1a,1b,1c,1d of the platelet 2; one of said bays or squares is rigidly secured to a fixed support, while the other bays are supported below, in alignment with the fixed bay, by supports which can be moved under control. Said movable supports may have various forms of embodiment, as illustrated below. Above the plate 4, there are present several pressing members 8, constituted for example of springs or of pneumatic or similar actuators, disposed in correspondence with each of the bays 4a,4b,4c,4d and adapted for pressing the ceramic platelet 2 against the plate 4, with the associated elements 1a, 1b,1c,1d in register with the bays 4a, 4b, 4c, 4d. The ceramic platelet 2, with the associated incisions 3a, 3b constituting the predetermined fracture lines, is clamped by the pressing members 8 against the plate 4, the latter being held with its upper surface flat by the associated movable lower supports. Thereafter, the lower supports of the plate associated with the bays aligned along one row, for example in Figure 1 the bays 4b and 4c, are lowered by a command; under the thrust of the upper pressing members 8, the plate 4 bends along the line defined by the groove 5 forming the boundary of the row of bays, and the platelet 2, clamped against the plate by the pressing members, is also subjected to bending, which causes it to fracture along the corresponding incision line 3 b. The supports of the plate 4 are then again raised, bringing the plate back into a plane, and the supports of another row of aligned bays are then lowered, for example the bays 4a, 4b; under the action of the pressing members 8, bending of the plate 4 now takes place, inclining the bays 4a, 4b, and fracture of the ceramic platelet 2 now takes place along the incision line 3a. In the case illustrated, said successive operations therefore lead to separation from one another of all the elements of the platelet; in the case in which the ceramic platelet 2 comprises a larger number of elements, further cycles of bending will be necessary to effect the complete separation of all the elements. The platelet, during the flexures which lead to fracture along the predetermined lines, is completely supported, and this therefore allows the platelet itself to be guided along the edges of the elements to be separated, thereby preventing the fracture from not being accurate, for various reasons, along the line defined by the incision. In Figures 2 to 4, a form of embodiment of the apparatus according to this invention is illustrated. As Figure 2 shows, the plate 4 is supported by a fixed support 9 on a base 10; above it there is present a movable frame 11, equipped with an associated actuator 12, which carries the pressing members 8, composed of pneumatic actuators 13, the rods of which are biased downwards by prestressed springs 14. The fixed support 9 is attached to a single bay 4e of the plate 4; the remaining bays 4f, 4g, 4h, 4i, 4m are supported by shafts 15, equipped with associated cams 16, connected together by gears 17 and toothed pulleys 18, which guarantee reciprocal angular correspondence to them; one of the shafts 15 is actuated by an associated motor 19. The platelet 2 is carried above the plate 4 by means of a thin belt conveyor 20, sufficiently flexible not to influence the bending of the bays of the plate 4. When the belt 20 has brought the platelet 2 above the plate 4, into a position defined by appropriate registering devices, not shown here, the frame 11 is lowered by the actuator 12 until the platelet 2 is clamped by the pressing members 8 against the plate, thus compressing the springs 14. In this phase, the cams 16 are all disposed in such a manner as to support the bays of the plate 4, resting upon them, in a horizontal position. The motor 19 then causes rotation of the shafts 15 and of the associated cams 16; these cams are arranged in such a way that, during the course of one complete rotation of the motor 19, they first lower the support of the bays 4h, 4i, 4m, thus causing bending of the plate 4 along the line defined by the relative groove 5a, thus separating the corresponding elements from the remaining platelet 2. The actuators 13 associated with said bays then retract their rods, thus coming into a position which no longer interferes with the separated platelet elements, while the further rotation of the shafts 15 brings the cams 16 into a position such as to restore the planeity of the upper surface of the plate 4. A further rotation of the shafts 15 brings the cams 16 into a position, which permits the downward deflection, under the action of the springs 14 of the pressing members again acting on the platelet 2, of the bays aligned along two other rows, transversely to the preceding row, that is to say of the bays 4g and 4h for one row and 4f and 4m for the other row, thus allowing the platelet 2 to fracture along two further incision lines, defined respectively by the grooves 5b and 5c. The rods of the actuators are now all retracted, thus freeing the separated elements from the ceramic platelet, which elements can now be removed by the belt 20 to the discharge point or for further processing. In Figure 5 there is illustrated an alternative form of embodiment of the invention, in which there is a base 21 which carries a movable upper frame 22, to which there are attached several pressing members 8, composed of controllable actuators 23, for example of pneumatic type; the base 21 carries a support 24, to which there is attached a bay 25a of a plate 25 of plastics material of considerable thickness, equipped with grooves 26 which define bending lines defining bays, in correspondence with the fracture lines intended for the ceramic platelet 2 to be subdivided, this ceramic platelet being conducted over the plate 25 by a flexible thin belt 27. In correspondence with the other bays 25b, 25c etc. of the plate 25, there are present at least an equivalent number of controllable actuators 28 which, in the extended position, keep the plate 25 with its upper surface plane, with a function analogous to that of the cams of the preceding example. The actuators 28 are controlled by a control unit, advantageously of programmable type, by means of which a succession of lowerings of the actuators themselves is defined, for example as indicated schematically in Figure 6, or according to analogous schemes, depending upon the topology of the fractures to be produced, as a result of which the flexures of the plate 25 are carried out, which lead to the separation of all the elements of the remaining platelet 2 clamped by the pressing members 8, in analogous manner to the preceding case. The upper pressing members 8 and the lower controllable actuators 28 may be of small dimensions and may be arranged at close spacings; in this way it is possible to adapt the apparatus to different arrangements of the fracture lines of the platelets and to different dimensions of the platelets themselves and of their individual elements, by replacing for each type of platelet only the plate 25 with an arrangement of grooves disposed according to the fracture lines intended for the platelet in question. In the case where the dimensions of the single platelet elements, and therefore of the single bays of the plate 25, are greater than those defined by the relevant distance between two contiguous actuators, each bay or some of the bays may rest upon two or more actuators, which will in this case be actuated in an integral manner, as illustrated in the right-hand side of Figure 5. This therefore makes it possible to use the same production line for different products, by simply changing the support plate, which supports the platelet along the desired fracture lines, and the programming sequence of the movements of the lower actuators. The plate 4, in an alternative form of embodiment, may also be made up in a composite manner of an upper flexible sheet, for example of steel of small thickness, beneath which there are secured by welding, gluing or the like, the rigid bays, for example of metal, separated from one another by grooves along the intended flexure lines.

Claims: Apparatus for the automatic separation along predetermined bending fracture lines (3) in basic ceramic platelets (2) of hybrid electronic circuits, characterized by the fact that the apparatus comprises a support plate (4; 25), provided with grooves (5; 26) on its lower face extending into close proximity with its upper face, these grooves (5; 26) defining bending lines disposed in correspondence with the bending fracture lines (3a, 3b....) of a ceramic platelet (2) placed in register on said plate (4; 25), which grooves (5; 26) form the boundaries of associated bays or squares (4a, 4b, 4c....) of the plate (4), which are rigid in bending, corresponding to the single elements (1a, 1b, 1c...) into which the platelet (2) is to be subdivided, upper pressing members (8) being present adapted for gripping each element (1a, 1b, 1c...) of the platelet (2) against the corresponding bay (4a, 4b, 4c...) of the plate (4), which plate is rigidly supported in correspondence with one single bay, lower opposing members (15, 16; 28) being present acting against each of the remaining bays, these opposing members being retractable under control in a predetermined sequence, the successive bending of the plate (4; 25) along the lines defined by the grooves (5; 26) of said plate (4; 25) being brought about by the action of the upper pressing members (8), said bending causing the fracture of the ceramic platelet (2) along the predetermined lines coinciding with the grooves (5; 26) of the plate. Apparatus for the automatic separation of basic ceramic platelets of hybrid electronic circuits according to Claim 1, characterized by the fact that the support plate is composed of a plate (25) of plastics material of large thickness, provided with notches (26) defining flexible diaphragms in the material itself along the intended bending lines for the plate. Apparatus for the automatic separation of basic ceramic platelets of hybrid electronic circuits according to Claim 1, characterized by the fact that the support plate (4) is composed of a flexible thin sheet, beneath which the bays are rigidly secured, these bays being composed of a material stiff in bending, and separated from one another by grooves (5) corresponding to the intended bending lines for the support plate. Apparatus for the automatic separation of basic ceramic platelets of hybrid electronic circuits according to Claim 1, characterized by the fact that the upper pressing members are constituted of thrust members (8) carried by one common frame (22) movable by an associated actuator means (23) between a position of engagement of the pressing members (8) with the platelet (2) and a position remote from said platelet. Apparatus for the automatic separation of basic ceramic platelets of hybrid electronic circuits according to Claim 1, characterized by the fact that the pressing members each (8) comprise an elastic pressure element (14) and a controllable retraction actuator (13). Apparatus for the automatic separation of basic ceramic platelets of hybrid electronic circuits according to Claim 1, characterized by the fact that the grooves (5; 26) of the lower face of the plate (4; 25) are composed substantially of inverted V-section notches, having their apex in proximity to the upper face of said plate. Apparatus for the automatic separation of basic ceramic platelets of hybrid electronic circuits according to Claim 1, characterized by the fact that the lower opposing members (15, 16; 28) acting against the free bays of the plate (4; 25) are composed of actuators controllable according to a predetermined sequence by a programmable control unit. Apparatus for the automatic separation of basic ceramic platelets of hybrid electronic circuits according to Claim 1, characterized by the fact that the lower opposing members acting against the free bays of the plate are composed of cams (16) having one or more lobes carried by associated parallel shafts (15), the shafts being actuated by one common motor (19), which cams (16) possess lobes disposed in reciprocal angular relationship determining the bending of the bays of the plate (4) along the lines defined by the grooves (5) according to a predetermined sequence. Apparatus for the automatic separation of basic ceramic platelets of hybrid electronic circuits according to Claim 1, characterized by the fact that a flexible, thin conveyor belt (20) for conveying the platelets (2) above the plate (4) is interposed between the ceramic platelets and the plate. Apparatus for the automatic separation of basic ceramic platelets of hybrid electronic circuits according to Claim 8, characterized by the fact that the lower opposing members and the upper pressing members are disposed according to a fixed grid, having a pitch equal to or less than the minimum dimension of the elements of the ceramic platelet and of the corresponding bays of the plate, at least one of the pressing members or of the actuators being in contact, respectively, with each element of the ceramic platelet and each bay of the plate.

Inventors: BAROZZI, GIAN PIERO
Applicants: AISA S.P.A.
Application year: 1989
Main classification: H01L21
IPC codes: H05K1, H05K3, B26F3, B28B11, B28D5