Piezo Linear Motors Provide 20mm Travel Ranges

PI has introduced the N-216 Nexline high-load piezo linear motors - ultra-precision nanopositioning actuators that provide travel ranges to 20mm and push/pull forces to 600N (130lb). The operating principle is based on coordinated motion of a number of highly preloaded linear and shear piezo elements acting on a ceramic runner. Nexline Piezowalk drives can be used in ultra-precision manufacturing and semiconductor test equipment to astronomy and high-energy physics applications.

Their reliability makes them suitable for applications in difficult-to-access internals of instruments, where nanometer-realm adjustment and/or vibration cancellation are required. To promote long lifetime, the Piezowalk controller can reduce the operating voltage on the piezo elements to zero at any position without affecting the full holding force (up to 800N, 177lbs). The piezoceramic clamping and shear elements act directly on a moving runner coupled to the load.

For maximum velocity and long-distance movements, the runner can be driven in full step mode. Extremely uniform motion and constant velocity is achieved with the nanostepping mode. Combining long travel ranges with piezo-class precision, Nexline Piezowalk drives offer a high-dynamics analogue operation mode over smaller distances. Open- and closed-loop operation N-216 linear motors come in two versions for open- or closed-loop operation, as well as in two different load configurations.

Closed-loop versions are equipped with a linear encoder for direct position measurement of the moving runner. The encoder features 5nm resolution over the full travel range. In open-loop operation a positioning resolution to 30 picometers can be realised by use of the analogue operation mode.

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New Scale Unveils Squiggle RV Linear Drive System

New Scale Technologies has introduced the Squiggle RV reduced-voltage linear drive system, which consists of an SQL-RV-1.8-6-12 Squiggle motor and an NSD-2101 drive ASIC. It is a miniature piezo motor drive solution with a driver chip that is smaller than the motor and driven directly from battery power as low as 2.3VDC, without the need for a voltage boost. The Squiggle RV motor is New Scale's next-generation piezo micro motor, using multi-layer piezo technology from TDK-EPC to reduce the input-voltage requirements of the motor.

The NSD-2101 driver was developed for this new motor in partnership with Austriamicrosystems using advanced integrated-circuit (IC) designs and patented control systems. This smart IC measures 1.8 x 1.8mm and drives the Squiggle RV motor directly, without the need for an external boost circuit. The Squiggle RV linear drive system is more than five times smaller and uses 40 per cent less power than comparable electromagnetic linear drive systems, according to New Scale.

The NSD-2101 accepts direct 2.3-5.5VDC battery power and uses patented full-bridge switching technology to create the ultrasonic motor drive frequency. The IC also includes built-in patent-pending smart drive features that optimise motor performance while minimising power consumption over a range of operating and environmental conditions. The NSD-2101 requires only DC battery power and digital I2C control commands to achieve good miniature motion control performance.

The SQL-RV-1.8 motor achieves forces in excess of 50g and a high resolution to 0.5 micrometers. It can run at speeds greater than 7mm/s with a power consumption of less than 350mW when moving under typical loading conditions. This corresponds to a DC current of 120mA for a typical 3VDC battery. Its self-locking design means that zero power is needed to hold the motor position, providing additional power savings. New Scale's Tracker NSE-5310 linear encoder can be integrated with the Squiggle RV system for high system repeatability with submicron resolution.

The reduced-voltage Squiggle RV micro motor is suitable for situations where high precision, miniature size and low power consumption are a must. These include medical, security, optical and imaging systems; consumer electronics; precision biomedical actuators; and miniature actuation for aerospace and industrial applications. Its small size makes it suitable for creating tiny, high-resolution integrated closed-loop motion systems.

New Scale's DK-RV-1.8 series of developer kits includes all hardware as well as the company's Pathway development software with scripting capabilities in a plug-and-play reference design for prototype development and integration. Open-loop developer kits contain an SQL-RV-1.8 micro motor and an NSD-2101 driver; closed-loop kits also include a New Scale Tracker NSE-5310 linear encoder. A 3D computer-aided-design file of the SQL-RV-1.8 motor and additional reference information is available from the company's website.

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Linear-Rail System Has Self-Adjusting Mechanism

The SBI range from Jena Tec offers low noise and high rigidity, coupled with a smooth movement and self-adjusting mechanism. According to the company, an increase of load-carrying capacities of up to 40 per cent can be achieved compared to standard block and rail systems. Compared to conventional linear rail cross sections, the SBI range is approximately 10 per cent lower, with a wider through section of nearly 20 per cent, Jena said.

Its improved lower cross-sectional centre point offers greater structural rigidity, improved straightness during manufacturing and straightness in application. Heat treated to HRC60, the SBI range is highly stable, while shorter cross-sectional areas mean grinding time and plastic deformation are reduced. Linear blocks are constructed from a hardened-steel rigid structure with the same lower cross-section centre as the rail and slightly longer block length meaning a greater number of balls with a smooth circular-angular motion.

This improved track profile and angle results in a smoother and quieter operation. Standard across the range of SBC products is the heat- and chemical-resistant end plate with moulded return systems and a self-aligning design to ensure the end plate is correctly fitted in line with the main steel block. Despite an increased load-carrying capability, the additional length attributable to the SBI range is approximately only 3-4mm longer than standard types, dependant on carriage model, which is made possible by an improved end-plate design.

Upper and bottom retainer plates fitted to each block ensure that loose steel balls are eliminated, as well as skidding and poor rolling performance within the load zone, preventing ingress of foreign substances. The SBI retainers are snap assembled and self aligning. The moulded return plate contributes to the smooth running operation of the SBC range, as well as keeping running noise low. The SBI range achieves this through an improved contact angle of 52 per cent, versus the industry standard of 53 per cent.

The lower radius of curvature provides a broader contact surface compared to the relevant ball size possible and therefore improves the rigidity. The improved angular ball recirculation system with four-row, two-point contact and 45deg angular orientation ensures that rolling performance is maintained with low noise at all grades of pre-load.

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