Method and apparatus for breaking prescored ceramic substrate plates

A prescored ceramic substrate plate is broken along each of a plurality of parallel, uniformily-spaced transverse score lines scribed therein by moving the plate, scored side up, along a guide rail and over a break edge into the lower arc of a resilient break roller which is free to rotate. First and second idler rollers apply pressure to the remaining portion of the plate as the plate is being moved. The break roller is canted in the X-axis at a predetermined angle with respect to the break edge for applying a graduated downward pressure onto the plate against the break edge. This angled orientation of the break roller to the break edge sequentially causes the plate to fracture incrementally along each score line as that portion of the plate located at the previously adjacent score line moves into the break roller.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
This invention relates to the fabrication of ceramic substrates and 
particularly to an automated apparatus and method for breaking a prescored 
ceramic substrate plate into a plurality of individual substrates in a 
manner which simulates the action of breaking the plate by hand. 
2. Description of the Prior Art 
The typical ceramics used in fabricating substrates for miniature thick 
film, as well as some thin films, resistor and capacitor components or 
circuits are composed of 92% to 99% alumina ceramic (Al.sub.2 O.sub.3), 
which is amorphous and very hard. The substrates typically are rectangular 
in shape, between 0.015 to 0.035 inches thick, less than 1.5 inches long 
and less than 1/2 of an inch wide. 
Impedance films for such resistor and capacitor components (and even 
inductor components), are conventionally formed on one surface of the 
substrate by evaporation in the case of thin film components or by 
conventional silk screen and firing techniques in the case of thick film 
components. When high volume fabrication is required, the components are 
usually produced by silk screening the patterns in multiple images (e.g., 
2 to 60 or more) in one pass on a large sheet or plate of ceramic 
material. The large ceramic plate can be prescored between pattern areas 
by green scoring the plate before it is sintered or by laser scoring the 
plate to size after it is sintered. The plate can also be postscored to 
size after the components have been deposited thereon. The scored 
individual substrates, with their deposited components, are then broken 
off of the larger ceramic plate. 
The methods currently used in mass production applications for breaking the 
individual substrates off of a larger ceramic plate are generally 
variations of two basic methods. In the first basic method, the plate is 
held stationary with a single unit extending over a break edge and then 
pressure is applied to the scribed side of the extended piece in order to 
break off the extended unit. In the second basic method, the plate is 
placed, scribed side down, on a resilient surface and a roller is rolled 
across the plate with an appropriate pressure to break off successive 
units. 
To date, however, the prior art breaking methods have been characterized by 
a lack of precise control over the application of pressures, thereby 
producing decidedly inferior results, in terms of the percentage of 
substandard or ruined substrates due to incorrect fractures, than those 
results achieved by manually breaking the individual pieces. However, such 
manual breaking is a slow and laborious method at best. Thus, until the 
present invention, high quality production could be achieved only by 
sacrificing the economy and efficiency of mass production. 
One attempt to avoid the trade-off between quantity and quality in ceramic 
substrate production is described in U.S. Pat. No. 3,507,430. This patent 
discloses a tool for snapping a prescored ceramic substrate plate into 
separate substrates. The tool has members which are seated within W-shaped 
grooves in the plate. The application of pressure to the members snaps a 
separate substrate off of the plate by removing the central portion of the 
W. While, in terms of speed, this is an advance over manually breaking the 
ceramic plate into separate substrates, the need for prescoring the plate 
with W-shaped grooves, rather than V-shaped grooves, adds to the expense 
of fabrication, over and above the expense of the specially fabricated 
tool required. 
Various other devices are known in the art for breaking scored workpieces 
into smaller pieces with both speed and accuracy. 
Each of the U.S. Pat. Nos. 2,042,819; 3,141,592; and 4,046,300 discloses an 
apparatus for breaking scored glass sheets. In U.S. Pat. No. 2,042,819, a 
scored glass sheet is broken along each scored line as that scored line 
moves between rollers. In U.S. Pat. No. 3,141,592, a scored glass sheet is 
broken along each scored line by the fulcrum action of a roller against 
one end of the sheet as each scored line of the sheet moves between two 
breaker rollers. In U.S. Pat. No. 4,046,300, a scored glass sheet on a 
conveyor, stopped over a breakout template, is broken by the movement of a 
roller over the scored line of the glass. 
In a similar manner, each of the U.S. Pat. Nos. 3,105,623; 3,601,296; and 
3,870,196 discloses methods and devices for breaking crystalline 
semiconductor materials. In each of U.S. Pat. Nos. 3,105,623 and 3,601,296 
a prescored crystalline semiconductor material, mounted on a resilient 
flat surface, is broken along each scored line as that scored line moves 
beneath a roller. In U.S. Pat. No. 3,870,196 a prescored crystalline 
semiconductor wafer, mounted on a flat resilient pad, is broken along the 
prescored lines as a roller is moved across the wafer. 
However, the above-described methods and devices for breaking glass sheets 
or crystalline semiconductor materials into smaller pieces are not readily 
adapted for use on ceramics, due to the unique properties of ceramic 
materials. The glass breaking devices are specifically used for breaking 
off relatively large pieces of a material which breaks with far less 
pressure than does alumina ceramic. The semiconductor breaking devices are 
designed for operation on material which is, as previously noted, 
crystalline in nature and which, therefore, easily cleaves along prescored 
lines. On the other hand, amorphous alumina ceramic lacks such natural 
cleavage. 
None of the above-described prior art devices and methods teaches an 
automated apparatus or method for selectively breaking a prescored ceramic 
substrate plate into a plurality of individual substrates in a manner 
which simulates the action of breaking the plate by hand. 
SUMMARY OF THE INVENTION 
Briefly an automated apparatus and method is provided for sequentially 
causing each of a plurality of score lines in a ceramic substrate plate to 
incrementally fracture along that score line, in a manner similar to that 
of the manual breaking of the plate, as the plate is moved along a 
predetermined path. 
In a preferred embodiment, a prescored ceramic plate is firmly guided along 
a predetermined path in a plane, over a break edge and into the lower 
portion of a break roller. The axis of the break roller is parallel with 
the plane and also canted at a preselected angle with respect to the break 
edge. This orientation of the break roller enables the break roller to 
initiate a graduated downward break pressure onto the plate against the 
break edge in order to cause the plate to incrementally fracture across 
one end of each ceramic substrate that is to be sequentially broken off of 
the plate. 
It is therefore an object of this invention to provide an improved 
apparatus and method for selectively breaking a prescored ceramic plate. 
Another object of this invention is to provide an automated apparatus for 
simulating the action of breaking a prescored ceramic substrate into 
individual components by hand.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
Referring now to the drawings, FIG. 1 illustrates a perspective view of a 
preferred embodiment of the invention. More particularly, FIG. 1 
illustrates an apparatus 6 for sequentially fracturing a ceramic substrate 
plate along parallel, uniformly-spaced, transverse score lines to produce 
a plurality of separate substances. The apparatus 6 includes a body or 
support table 8 having legs 10. Table 8 has a sloping, 
rectangularly-shaped framework 12 having side rails 14 and 16 and an end 
rail 18, which rails collectively define a rectangularly-shaped outer 
perimeter. A tilted flat upper surface 20, which is longitudinal in shape, 
lies within the perimeter formed by the rails 14, 16 and 18. The table 8, 
and hence the surface 20, may be made of stainless steel or some other 
suitable abrasive-resistant material. The far end of the longitudinal 
surface 20 terminates at a linear break edge 22 near to and parallel with 
the end rail 18. The break edge 22 is defined by the intersection of the 
far end of the surface 20 with one wall 24 of a rectangularly-shaped slide 
track 26, formed in the body 8 transverse to the longitudinal direction of 
the surface 20 and between an inner wall (not shown) of the end rail 18 
and the far end of the surface 20. 
First and second idler pressure rollers 28 and 30 are each rotatably 
mounted between the rails 14 and 16 at a predetermined distance from the 
surface 20 and in tandem along the longitudinal axis of the surface 20. A 
break roller 32, larger in diameter than the rollers 28 and 30, is 
rotatably mounted over the slide track 26 and between the rails 14 and 16. 
It should be noted at this time that, for purposes of this discussion, 
orthogonally displaced X and Y axes (shown as dashed, directional lines X 
and Y) will be defined as lying in a plane perpendicular to the surface 
20, with the X-axis lying in the plane of the surface 20 and being 
parallel to the side rail 16. The axes of rotation (not shown) of the 
rollers 28, 30 and 32 are each parallel to the surface 20, with the axes 
of the pressure rollers 28 and 30 also being perpendicular to the X-axis. 
The roller 32 is adjustable by, for example, conventional micrometer means 
(not shown) in the X-axis away from or closer to the break edge 22 and in 
the angle of cant with respect to the break edge 22, and in the Y-axis 
away from or closer to, but still parallel with, the surface 20. 
Preferably, the roller 32 is positioned so that its axis is canted in the 
X-axis at a predetermined angle .phi., for example between 2.degree. and 
5.degree., with respect to the break edge 22 and is also positioned in the 
Y-axis so that the bottom edge of the roller 32 is slightly below the 
bottom edge of each of the rollers 28 and 30 (to be discussed). 
Preferably, the rollers 28, 30 and 32 are all made of polyurethane, with 
each of rollers 28 and 30 having a hardness of 80 to 90 durometer and 
roller 32 having a hardness of 30 to 40 durometer. Furthermore, the 
rollers 28, 30 and 32 are preferably not driven but are free to rotate. In 
addition, the assembly comprised of the flat surface 20, rails 14, 16 and 
18 and rollers 28, 30 and 32 is preferably mounted to the table 8 at an 
angle, for reasons which will be subsequently discussed. It should, of 
course, be realized that, within the purview of the invention, said 
assembly could obviously also be mounted level to the table 8 at a 
0.degree. angle. 
A prescored ceramic substrate plate 34, having a plurality of 
uniformly-spaced transverse score lines 36 scribed therein, is placed 
scribed side up on the surface 20 between the side rails 14 and 16. Since 
the surface 20 is tilted, the plate 34 slides down to and rests against 
the side rail 16. 
The ceramic substrate plate 34 is preferably composed of a high alumina 
content material, e.g., 92% to 99% alumina ceramic (Al.sub.2 O.sub.3), 
which is amorphous and very hard. However, other materials, such as 
zircon, aluminum silicates, zirconium dioxide, titanium dioxide, magnesium 
silicates, barium titanate and combinations thereof, may be used. The 
width between adjacent score lines 36 is greater than the radius of each 
of the pressure rollers 28 and 30. 
A pushing or moving means 28 is used to move the plate 34 along the 
longitudinal surface 20. Since one edge of the plate 34 is against the 
side rail 16, the rail 16 acts as a guide to assure that the orientation 
of the plate 34 is maintained as it is being moved. The moving means 38 is 
comprised of a steel plate 40 equal to or less than the thickness of the 
plate 34 and a thin shaft or rod 42 attached between the steel plate 40 
and an end means 44. The leading edge of the steel plate 40 may be 
beveled. The end means 44 may be pushed by hand or may represent a linear 
DC (direct current) motor or a float-controlled air cylinder (not shown) 
which automatically moves the ceramic plate 34 (via the shaft 42 and steel 
plate 40) a predetermined distance before restracting. 
In the operation of the apparatus of FIG. 1, the movement of the steel 
plate 40 slides the ceramic plate 34 on the surface 20 along the rail 16, 
under the pressure rollers 28 and 30 and past the break edge 22 into the 
break roller 32. Such a positive push force, in cooperation with the 
guidance of rail 16, eliminates skewing and an unevenly applied force, 
which could result in uneven breaks in the ceramic plate 34. 
At this point, reference will be made to FIGS. 2 and 3 to further, and more 
clearly, show the operation of the apparatus 6 of FIG. 1. Each of FIGS. 2 
and 3 is a side elevation view of the apparatus 6 with certain parts 
removed, such as the legs 10 and rails 14, 16 and 18, to more clearly 
disclose the structure therebeneath. 
As the ceramic plate 34 is being pushed by the moving means 38 under the 
idler rollers 28 and 30, and into the break roller 32, the rollers 28 and 
30 rotate in the indicated clockwise direction and apply pressure to the 
plate 34 thereunder. It will be recalled that the axis of the break roller 
32 is canted in the X-axis with respect to the break edge 22 and that the 
bottom edge of the roller 32 is positioned below the bottom edge of each 
of the rollers 28 and 30. More specifically, the bottom edge of the roller 
32 is positioned below the upper surface of the plate 34 so that one 
corner (not shown) of the front edge of the plate 34 will initially strike 
a lower arc of the canted break roller 32. At this time, the first score 
line 36 from the end of the plate 34 that is making contact with the 
roller 32 may be a few mils behind the break edge 22. As soon as the break 
roller 32 makes contact with the front edge of plate 34, the roller 32 
starts to apply a graduated downward pressure onto the plate 34 against 
the break edge 22. As the plate 34 continues to move forward, more and 
more of the front edge of the plate 34 moves into contact with the lower 
arc of canted roller 32. The angled or canted orientation of roller 32 
thus causes the plate 34 to fracture incrementally along the score line 
36, thereby simulating a manual breaking action. 
The entire breaking action normally takes only a few microseconds to 
happen. Optimally, a complete break should occur when the plate 34 has 
been pushed about 1 mil beyond the break edge 22. However, realistically 
the complete break across the score line 36 of the plate probably occurs 
between 1 to 5 mils beyond the break edge 22, because of varying 
tolerances in the score lines 36 and material of each broken piece. 
The broken piece or separate substrate 46 is shown in FIG. 2 falling down 
onto the slide track 26. As shown in FIG. 3, the separate or individual 
substrate 46 slides down the slide track 26 onto an endless conveyor belt 
48 which carries the substrate away to, for example, a work station (not 
shown). 
The plate 34 can be moved at an exemplary velocity of 2 to 3 inches second. 
The above-described breaking operation is repeated for each substrate 46 
that is broken off the plate 34, except for the last one. For a plate 34 
that is initially 1 to 2 inches long, a given number of, for example, 
between 4 and 20 separate substrates 46 can be broken off. The number of 
substrates depends upon the desired width of each separate substrate 46. 
The moving means 38 (FIG. 3) retracts, or is retracted, after the last 
substrate 46 falls onto the slide track 26. 
As indicated before, the assembly comprised of the flat surface 20, rails 
14, 16, and 18 and rollers 28, 30 and 32 could be mounted level to the 
table 8. In such an implementation, means, such as horizontally adjustable 
side rollers, could be mounted to the side rail 14 to maintain the 
orientation of the plate 34 by forcing the plate 34 against the rail 16, 
and the slide track 26 could be tilted to enable each substrate 46, that 
is broken off of plate 34, to slide away from the break edge 22. 
The invention thus provides an automated apparatus and method for 
sequentially causing each of a plurality of score lines in a ceramic 
substrate plate to incrementally fracture along that score line, in a 
manner similar to that of the manual breaking of the plate, as the scored 
plate is moved along a predetermined path, under pressure rollers, over a 
linear break edge and into the lower arc or portion of a horizontally 
canted break roller. 
While the salient features have been illustrated and described in a 
preferred embodiment of the invention, it should be readily apparent to 
those skilled in the art that modifications can be made within the spirit 
and scope of the invention as set forth in the appended claims.