Vacuum chuck for EDM

Vacuum chuck for EDM

The National Institute of Standards and Technology (NIST) has created a vacuum chuck and a vacuum-creating aspirator pump for EDM equipment to hold parts vulnerable to distortion by vises, clamps, or other two-surface clamping methods. Anticipated advanta

NIST has created a vacuum-chuck workholding system for EDM that uses an aspirator and the machine's dielectric fluid to create the suction force for holding workpieces.


The National Institute of Standards and Technology (NIST) has created a vacuum chuck and a vacuum-creating aspirator pump for EDM equipment to hold parts vulnerable to distortion by vises, clamps, or other two-surface clamping methods. Anticipated advantages of a vacuum chuck include simplified holding of otherwise hard-to-hold workpieces, no tooling marks, fewer setups, faster cycle times, higher yields, and expanded capabilities of EDM equipment.

The innovation is largely a matter of plumbing. NIST incorporated a vacuum-creating aspirator (everyday equipment in chemistry laboratories) into an EDM. A tube situated after an already-existing pump siphons off a portion of the machine's insulating fluid. The fluid shoots down the tube and creates a vacuum in another tube connected to the workpiece holder, all of which creates the suction that secures the workpiece.

Unlike piston pumps and membranes that can also create a vacuum, an aspirator is insensitive to large volumes of water, dirt, and grime. While vacuum chucks are typically not as effective for machining operations that exert high cutting forces, in the case of EDM, tooling forces are below the threshold of the vacuum created by the aspirator.

NIST says the system is durable enough for 24-hour/day machining, and incorporating an aspirator into a commercial EDM would only require simple design change. Retrofitting existing equipment would cost several hundred dollars.

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