Spray Deposition Research Positioning System

Motion Control in R&D for Oxford MaterialsThe University of Oxford’s Department of Materials – Oxford Materials – approached LG Motion to design and manufacture an XYZ gantry positioning and motion control system for a research project using innovative spray deposition to manufacture thin and think film energy storage electrodes and devices.

The aim of the project is to demonstrate benefits over existing manufacturing processes and develop new processing technologies that offer cost-effective scaling to the near-industrial, and then full industrial use.

The Science

The research project, ‘Spray processed electrodes in new materials for energy storage applications’, is led by Professor Patrick Grant and explores layer-by-layer spray forming of electrodes for use as electrochemical ‘supercapacitors’.

The technique is to develop smaller, more efficient, longer life storage solutions for mobile phones, computers and other devices than current technologies.

The objective was to provide a cost-competitive mechanical positioning and motion control system that would enable a scanned area of 300 mm x 300mm in the horizontal plane, with a vertical axis to position the spray head over 200 mm.

The objective for the Scientists was to increase flexibility and research throughput in the laboratory. The design specification called for an XYZ positioning rig with the ability to load multiple sprayheads up to 3kg mass within an area of 300mm x 300mm in the horizontal plane and 200mm in the vertical plane.

The Engineered Solution

To solve the problem, UK designer and manufacturer LG Motion applied their core motion technology experience with engineering skills to provide a robust system that met all of the Customers objectives.

The custom-built Spray Deposition Positioning System is based around modular products that have been integrated to match customer requirements. The system specification called for relatively low speeds, low duty cycle and medium precision to perform the required scanning with a load of up to 3kg.

To maintain budget constraints, an open loop stepper motor based positioning system was used, centred on LG Motion’s linear dovetail slides, the XSlide range powered by high-torque stepper motors and uses standard bracketry and modular mounting to maintain overall flexibility.

To improve the consistency of tests and ease of use for multiple students and researchers, LG Motion also provided a simple GUI front-end program that allowed simple entry of scan patterns and spray timings without the need to program.

The Components

The gantry is mounted on a machine frame built with the MiniTec Aluminium Profile System and consists of a single XSlide stage to one side with its moving carriage coupled to a Schneeberger linear bearing guide and carriage on the other side of the gantry.

These carriages together support the Y-axis XSlide with the Z-axis vertical stage simply mounted via an angle bracket.

The stepper motors are fitted with hand wheels to aid manual positioning and over-travel limit and datum switches ensure safe operation under full control. The mechanical system also includes a cable management system which is easily supported within the design using the MiniTec machine frame.

The Arcus Technology PMX-4ET-SA, as an advanced 4-axis motion controller and stepper drive provided linear and circular axis interpolation, a 6 MHz step and direction pulse rate for smooth and fine resolution microstepping combined with fast synchronising inputs and outputs for the coordination of motion and external events required for the application.

With 10Mbps Ethernet communication that provides advanced features only found on more expensive motion controls.

The Result

During the design approval, manufacture and commissioning, LG Motion worked closely with scientists at Oxford Materials to ensure that the Spray Deposition Research Positioning System met all development and operational requirements.

As with many development processes, flexibility was a key factor in system design. The mechancial assembly is modular and the Arcus Controller offers easy and straightforward programming via Ethernet. This programming flexibility allows Oxford Materials to adapt the system as the research project progresses, including the ability to add encoder feedback for position verification should they wish to increase the system repeatability in the future.

LG Motion worked closely with Oxford Materials during all phases of this successful project and delivered the complete system, pre-wired and fully tested for use on the project.

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