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Measuring Device for Waterjet Cutting Quality

IP.com Disclosure Number: IPCOM000060034D
Original Publication Date: 1986-Feb-01
Included in the Prior Art Database: 2005-Mar-08
Document File: 2 page(s) / 63K

Publishing Venue

IBM

Related People

Alexander, JM: AUTHOR

Abstract

An automatic in-process arrangement to determine the cutting quality of a waterjet that is cutting printed circuit cards is described. A waterjet device is used to profile or cut printed circuit cards out of panels. The cutting is accomplished with a needle-thin stream of high-pressure water discharged through a sapphire orifice at up to three times the speed of sound. The quality of cutting is measured by the extent of delamination, edge surface finish, and width of cut. Cut quality degrades with time as the orifice wears or is otherwise damaged. A method to determine when the orifices should be replaced is described. The only known in-process method to determine quality is a visual observation of the length of the water stream which is clear.

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Measuring Device for Waterjet Cutting Quality

An automatic in-process arrangement to determine the cutting quality of a waterjet that is cutting printed circuit cards is described. A waterjet device is used to profile or cut printed circuit cards out of panels. The cutting is accomplished with a needle-thin stream of high-pressure water discharged through a sapphire orifice at up to three times the speed of sound. The quality of cutting is measured by the extent of delamination, edge surface finish, and width of cut. Cut quality degrades with time as the orifice wears or is otherwise damaged. A method to determine when the orifices should be replaced is described. The only known in- process method to determine quality is a visual observation of the length of the water stream which is clear. The device shown gives an in-process electrical feedback of the stream quality and thus indirectly the quality of the cut. The principle of operation is to sense the force of the waterjet at a given distance after it has passed through a hole of a certain diameter. The distance from the orifice to the hole, the hole size, the distance from the hole to the anvil which will be impacted, and the level of the force to be sensed are determined experimentally. Force detection is primarily performed by compressing a spring to allow an electrical contact. An alternative is to use a load cell so that quantitative measurements are obtained. The disadvantage of the latter is greater size...