ASIA - Bobst Group recently sold a General multi-chamber PECVD vacuum roll coater in Asia for clear barrier coatings.

Bobst Group recently carried out an installation, commissioning and process

With growing demands for increased shelf-life of food products and chemical inertia of the contact surfaces, there is now a greater need for the stimulated development of polymers with improved high-barrier properties.

This is the latest product line to be added to General's ever expanding portfolio of vacuum web coating solutions, which are predominantly aimed at the flexible packaging sector.

After significant investment in engineering design, process optimisation and project management, General Vacuum Equipment Ltd. (GVE) has developed an improved method of depositing thin layers of predominately inorganic glassy barrier materials with carbon inclusions. This provides a transparent film with high barrier protection against moisture and oxygen, whilst maintaining durability against stretching and bending, an issue which conventional ceramic coatings failed to overcome.

The General CVD vacuum coater features a modular chamber concept which can process web widths up to 2100 mm (82.7 in), with a maximum roll diameter of 1000 mm (39.4 in), running at speeds from 6 to 600 m/min (19.7 to 1968 ft/min) or even higher, dependent upon barrier requirements or the number of process modules. Optional equipment can also include plasma pre- and post-activation, a transmissive web detection system and various pumping and cryogenic options.

A high accuracy AC vector drive system provides advanced web handling, precise process monitoring (power levels, gas flows etc.) and control for superior deposition uniformity and product quality.

Its unique load lock design enables easy loading and unloading of the machine, without breaking the main process vacuum. A fully retracting chamber lid and process source enables operator-friendly cleaning and web threading, with the intention of maximizing process productivity.

Nick Copeland, Development Manager, GVE, explained, "The modular design of the General CVD coater allows for varying process requirements, whilst reducing the number of process modules limits the initial capital investment in a fairly new, but rapidly growing market.

"Further modules can be added later to increase production levels when customer demand dictates. An intuitive software interface enables easy interaction with the control system for rapid process configuration, data input & retrieval and process monitoring."

In addition to the production CVD coater, process trials have been carried out and various analytical measurements have been performed on a 300 mm (23.6 in) wide CVD pilot machine at GVE's facilities in Heywood, near Manchester, UK.

"This development time was made available prior to the scale-up of the large production coater and gave the customer the confidence they needed prior to advancement to the large, multi-chamber machine," Copeland confirmed.