Method for Simultaneously Cutting a Plurality of Circuit Boards

This invention relates to the apparatus for and method of cutting a plurality of various sized and shaped pieces of circuit boards from a stack of panels of the core material. The apparatus eliminates the necessity of fabricating a special jig for each run of pieces.

Small manufactured pieces, such as circuit boards, have been traditionally cut to specification from larger manufactured panels of the desired base material. Obviously, the greater the number of panels that may be cut into identical boards or pieces at one time the lesser the total time involved both in set up and in manufacturing and thus a reduction in the cost per unit results.

In the past, a plurality of panels have been stacked upon a supporting fixture and then, using a template or other device to determine the location and shape of the resultant boards, sufficient pins were driven through the panels such that when the panels were cut there would be two pins in each stack of resulting boards. The securement pins thus assured that the boards would be accurately cut, would remain stacked and would be relatively easily removed as a unit. Obviously, the cutting, once the panels and resultant boards were laboriously secured by the pins, could be accomplished by a numerical control machine if such were desired.

It becomes apparent that although this heretofore utilized method of cutting a multiple of small items such as circuit boards from larger panels does permit the utilization of automatic machines to simultaneously cut a stack of the panels, the setup time was necessarily slow and meticulous work.

A perforate table fixture overlying a plenum and including a plurality of upstanding pins is used to accurately locate and hold secure a stack of material to be cut into smaller pieces. The pieces are partially cut with a numerically controlled or other automatic device, a sheet of imperforate material is placed over the stack, a vacuum is created within the plenum holding the entire stack of material in a fixed position and the remaining tab portions are cut, completing the operation.

FIG. 1 is a plan view of a fixture for use in the present invention, including a stack of panels to be cut, overlying a portion of the novel fixture.

FIG. 2 is a sectional elevation view of the fixture of FIG. 1.

FIG. 3 is a partial plan view similar to FIG. 1 but depicting a plurality of parts cut from the panels with the retainer tabs left intact.

FIG. 4 is a vertical sectional view showing the cut pieces overlaid by a sheet of imperforate film material allowing the final cut.

As seen in FIG. 1, the apparatus which allows the largely automatic cutting of a plurality of panels into smaller units includes as its primary element a fixture, generally designated as 2, which includes a perforate upper surface 4, a plurality of upstanding locating pins 6 and a connection 8 to a vacuum source, as explained hereinafter. A plurality of full sized panel members 10 are placed upon the perforate surface 4 located and secured by pins 6, where they will be cut into the appropriate sized and shaped boards by means of a numerically controlled device.

As seen in FIG. 2, which is a partial sectional view of the fixture of FIG. 1, the perforate upper surface 4 includes a plurality of bores 12 in fluid communication with a plenum 14 created by a lower and side wall surface 16. A conduit 18, in commmunication with conduit 8, leads to a source of negative air pressure. In use, as explained hereinafter, the plenum 14 is evacuated at the appropriate time, thus holding the individual elements in position during the final cutting step.

As seen in FIG. 3, the panels are again designated as 10 but there is shown a plurality of individual elements, in this case circuit boards, in particular designated as 20, which have been partially cut from the stack of panel members 10. Each of the individual boards is left secured to the panel itself by means of tabs 22, one for each board, such that the stack of panels and each individual panel remains intact. It is to be emphasized that the majority of the perimeter of each of the boards 20 has been cut free.

In practice, the operator, to cut circuit boards by the present invention, places a stack of panels 10 upon the fixture 4 utilizing the locator pins 6 and then, utilizing a preprogrammed numerical control router or cutter, has a stack of the boards individually cut about the majority of their perimeter. Following the initial cutting, the operator then will place a sheet of imperforate film 24 (see FIG. 4) over the entire stack of panels and a negative pressure is created in the plenum 14. The negative pressure acting against the imperforate film holds the stack of panels in position and the numerical controlled machine is again activated to remove the tabs. The fact that the sheet of film 24 is in an overlying position and is to a large extent imperforate, the exception being that small portion where the tabs are cut, all of the pieces are held in place until the cutting is completed. The vacuum is terminated and the individual stacks of boards are removed.

In addition to the economy realized in the use of the present method, the waste material, a fine powder-like sawdust is removed from the work area by the vacuum.

Thus as can be seen, the present invention comprises a unique efficient method of automatically cutting a plurality of individual elements from a stack of panels of stock material.