Numerous biomedical applications, such as pipetting, biological and pharmaceutical assays and sample handling require the precise dispensing of fluids.

In many cases, the fluid volumes are incredibly small, on the order of micro-milliliters (or micro-mils), with margins of error lower than 5%. Equipment that fails to meet these stringent dispensing and accuracy requirements is simply unacceptable in the bio-medical market; this leads to erroneous results.

Fluid micro-dispensing is usually accomplished by the use of pipettes, syringe pumps or nozzles. These positive displacement devices can dispense small volumes of liquid through the accurate positioning of a piston down a bore. The key to accurate fluid dispensing are the mechanisms used to position the piston. These mechanisms must be capable of very fine motion with a very high level of accuracy and repeatability while dispensing fluids that may have different molecular weights, surface tensions and viscosities.

The ElectroCraft AxialPower™ Enhanced Series (APES) of linear actuators use a high-resolution stepper motor together with a fine-pitch lead screw or ball screw, which is attached to the piston mechanism of the micro-fluid dispenser.

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