Ceramic servo motors offer more accuracy

A novel 'ceramic servo motor' range - in terms of pricing - is at the same level as a microstepping drive package but has greater accuracy without any rotary screw drive parts.

The recent announcement by Micromech of the launch of these exciting new nano-motors has like some political parties failed to get its message across.

The Servocraft range of nano-motors are a novel 'ceramic servo motor' - a design that lends itself to the fabrication of special micro-miniature linear and rotary motors with the capability of nanometric resolution.

Manufactured by Nanomotion of Israel these patented motors are finding many new design slots once the technology is understood.

The standard larger nano-motors in the Servocraft family are the HR series which are very compact offering dynamic stall forces from 4N with the HR-1 single element unit up to 30N for the HR-8 an eight element unit.

They can be used to drive linear stages and rotary axes via ceramic collars or discs and can achieve resolutions down to below 10nm.

The motion is extremely smooth without any of the normal mechanical disturbance associated with circulating bearings and can run at surface speeds of up to 250/s while having a feasible step resolution of an amazing 5nm.

The nano-motors can be supplied in ultra high vacuum compatibility to cover environments up to 10 -10 Torr and non-magnetic formats.

Then there is the LS range (low speed) with less force but similar specifications to the HR range and designed to suit low speed applications, which do not exceed 20mm/s.

The smallest standard production nano-motor is the single element ST type that can be supplied in either standard or vacuum versions.

They have a dynamic stall force of 1.2N and can impart a surface speed of up to 250mm/s.

Even smaller but for volume users is the 'size of a pin' motor the Nanoserv range, which are made to suit custom requirements such as miniature digital camera focussing, precise compact medical or pharmaceutical applications.

An exciting feature of these products it should be noted, is that all of the above nano- motors exhibit virtually zero inertia and have a response bandwith of 40kHz so very fast settling time is achieved.

There is of course a range of drive amplifiers designed to suit varying needs and applications.

All units accept a standard 0-10V DC analogue command signal input which results in zero to maximum linear speed.

The small AB4 amplifier can drive up to 4 elements, for example two HR-2 motors, whereas the larger AB5 unit can handle up to 32 elements, that is four HR-8 motors.

Multiple amplifiers may be used to drive a quantity of motors and usefully it is not necessary to synchronise the 40kHz-modulation output.

Other amplifier features include step mode for burst pulsing, which is very handy for manual joystick targeting, and a DC flexure mode in which the element is biased into the final position rather than run at speed.

In terms of pricing these drive systems are at the same level as a microstepping drive package but have the advantage of greater accuracy and the obviation of any rotary screw drive components in the assembly.

The Servocraft nano-motors from Nanomotion offer a range which covers most motion tasks in research, science, pharmaceutical, optical, semiconductor, astronomical and light industrial establishments.

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