Electrochemical grinding, to two-shot molding

It's day two or is it day three here at the MD&M show in Anaheim Calif. -- jet lag and all the excitement has made me lose all sense of day and time!

There is some pretty amazing and cool new technology on display. Here are just a few examples that caught my eye:

-- Machines from Everite Machine Products in Philadelphia grind and cut difficult materials regardless of their hardness or strength. The machines use an entirely different kind of machining process called electrochemical grinding (ECG). In ECG, the anode is the workpiece and the cathode is the conductive grinding wheel. A continuous stream of electrolyte flows at the interface of the grinding wheel and workpiece and passes the current in the circuit. Since ECG does not rely solely on an abrasive process, the results are precise cuts free of heat, stress, burrs, and mechanical distortions. Good applications include grinding the hole in needles and trocars. Under an electron microscope, it can be seen that abrasive grinding and grit blast deburring does not remove burrs, but rolls them to the inside. ECG, in contrast, shows a perfectly smooth edge.

-- Metrigraphics in Wilmington, Mass. makes microcircuitry in which high-resolution photolithography, thin-film coating, and microminiature 2D and 3D precision electroforming combine for a high density, multilayer flexible circuit with 5-micron traces and spaces. The circuits can be placed in implantable devices for diagnostic imaging, monitoring, and drug administration.

-- Silicon formulations from Saint-Gobain's plastic division allow what is called two-shot molding. Basically, plastic and silicone components can be molded together in one operation.

-- PCB mount pressure sensors from Kavlico Corp. in Morpark, Calif., uses piezo-resistive sensing that lets designers select a standard voltage output device, or alternative digital SPI output. Selecting digital output lets designers eliminate components due to the embedded 10-bit analog-to-digital converter. This saves space, component costs, and reduces power consumption.

-- CMP Global in Barbados, BB, performs what is called pressure diecasting. This injects molten metal into a steel mold under pressure to form a near net shape product. It is a cost-effective way to produce metal parts for large volume production.

-- New packaging machines from RapidPak in Lodi, Wisconsin, do not use air bladders to seal products like traditional machines. Rather, they use a patent-pending method in which servos apply the sealing pressure. This provides a closed loop system because the torques from the servos can be used as process parameters: A too-high torque, for example, lets the system know there is something wrong.

-- A process called rotational molding produces spherical shapes with one piece construction -- there are no bonded seams to come apart. Albert International in Gainsville, Georgia makes things like blood pressure bulbs, in-line pumps, and syringes with this process.

-- Rogan Corp. in Northbrook, Illinois overmolds liquid silicone rubber directly to plastic and metal parts. This works well in applications such as waterproofing complex geometries and electronic interconnects.

The Anaheim Convention Center is not too bad looking, and seeing some sunshine is great. But California is unseasonably cool like most of the rest of the country.

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