Linear actuators enhance bio-medical equipment

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.

Figure 1. The unique design of the linear actuator enables it to have a higher output force per frame size than similar competitive offerings.
Figure 1. The unique design of the linear actuator enables it to have a higher output force per frame size than similar competitive offerings.

The ElectroCraft hybrid stepper motor can make 51,200 micro-steps per revolution. When combined with an
integrated fine pitch lead screw or ball screw, this hybrid stepper
linear actuator can provide micro-mil resolution with sub-micro-mil accuracy. The unique design of the
linear actuator, including motor shaft and insert, enables it to have a higher output force per frame size
than similarly sized competitive offerings. This allows the device to accurately dispense a wide variety
of fluids with different molecular weights, surface tensions and viscosities.

ElectroCraft’s AxialPower™ family of linear actuator products are available in the most popular frame
sizes, including 28 mm (NEMA 11), 56 mm (NEMA 23) and most recently a high-performance 42 mm (NEMA 17) frame
size. This new linear actuator is highly configurable and available with a variety of imperial or metric
leadscrew options with resolutions ranging from 0.006 mm to 0.050 mm per step, with an incredible output
force of up to 1001 N (225 lbs.). The APES 17 offers 40% more force than competitive size 17 designs. The
numerous available frame sizes provide original equipment manufacturers with the precision, performance and
reliability that is needed for a wide variety of micro-fluid dispensing applications.

ElectroCraft, Inc., based in Stratham, New Hampshire, is a global provider of dependable, application-
engineered fractional-horsepower motor and motion control products. With over 60 years of operation, they
have developed a comprehensive product line of motion control products including AC motors, PMDC motors,
brushless DC motors, stepper motors, servo motors, gearboxes, gearmotors, linear actuators, drives, servo
drives and integrated motor drives. These products have been successfully integrated into numerous applications
in several industries, including biomedical and lab equipment. For OEM
customers dissatisfied with having to design around inflexible off-the-shelf products, ElectroCraft’s technical
knowledge and customizable product families provide motion control systems that provide superior reliability
and performance at the lowest possible cost. More information about the AxialPower™ Enhanced Series of linear
actuators can be found on the ElectroCraft website.