To replace Vespel electrical insulators in plasma cutting torches, a manufacturer chose lower cost PEEK polymer that offered the same electrical insulating and high temperature properties.

When Esab Welding and Cutting Products of Florence, South Carolina, USA, wanted to replace the Vespel electrical insulators in their plasma cutting torches, they chose Victrex PEEK polymer. The polymer offers the same electrical insulating and high temperature properties as Vespel but is less expensive and easier to machine. Plasma cutting torches are used to cut and fabricate metal parts.

They utilize electricity to create an arc between the electrode (torch body) and the work piece.

'The arc is forced through a nozzle with a small hole in it along with a flow of gas, such as air, and this results in the air becoming very, very hot, up to tens of thousands of degrees,' explains Stan Severance, Staff Engineer at Esab.

'As a result, this high temperature effluent of gas along with the arc can cut through metal.' Located in the head of the torch, the PEEK polymer insulator electrically insulates two different potentials inside the torch from each other.

Explains Severance, 'A torch typically has two electrical potentials.

One is associated with the electrode and the other is associated with the nozzle.

In order to start the torch, an arc is struck between the electrode and the nozzle which is called a pilot arc.

Once the pilot arc makes contact with the work piece, the arc transfers to the work piece.

It is necessary to separate the electrode potential from the nozzle potential.

This means having one or more insulators inside the torch body to insulate the two potentials from one another.' Because the insulators are exposed to the high voltage electrical discharge used to start the torch, they must be able to withstand very high temperatures.

Explains Severance, 'To get the arc started, you can have very high voltages - up to 10,000V - at high frequency, plus temperatures can be very high especially in air-cooled torches.' Before switching to PEEK polymer, Severance said 'We looked at a variety of different materials.

Vespel is very expensive and it has a very complicated manufacturing process.

We wanted a material that would be substantially less expensive but still have all the properties needed to meet the requirements of the application.

In addition to good electrical insulative properties and good high temperature properties, we wanted machinability, heat aging and creep resistance.

PEEK polymer fulfills all these requirements.' With operations in a large number of countries, Esab is the world's largest producer of welding and cutting consumables and equipment.

When a leading manufacturer of industrial cleaning equipment, wanted a material for the helical gear wheels in its spray heads, it chose a polymer because of its superior chemical resistance.

When Toftejorg A/S of Denmark, a leading manufacturer of industrial cleaning equipment, wanted a material for the helical gear wheels in their equipment's spray heads, they chose Victrex PEEK polymer because of its superior chemical resistance and high mechanical strength. According to Andrew Ragan, Victrex Global Leader polymer was chosen because of its resistance to virtually all organic and inorganic solvents, and because it delivers the required high mechanical fatigue strength over a wide range of temperatures and pressures.' The cleaning equipment is used in a variety of demanding environments including cargo ship containers for transporting crude oil, chemicals or solid bulk products. The containers are cleaned after the cargo has been unloaded to prevent contamination of the new cargo.

Depending on the applied pressure and nozzle system used, the equipment can completely clean a tank within a few minutes.

The gear wheels are manufactured in a custom mold specially designed for co-injecting an unfilled PEEK polymer resin onto a pre-heated metal insert.

Using the polymer gives the wheels the ability to resist high mechanical loads and provide long-term resistance to both cleaning agents and aggressive residual media in the storage tanks.

And, because unfilled PEEK polymer complies with FDA regulations for repeated food contact, Toftejorg can also market its products to the food and beverage industry.

Victrex USA, a division of Victrex., is the sole manufacturer and supplier of PEEK polymer worldwide.

For more information on the properties and performance advantages of Victrex PEEK polymer, please call (800) Victrex or visit the Victrex website.

The PEEK trademark - for many years Victrex has been using the PEEK trademark to refer to its brand of Polyaryletherketone.

Victrex is the sole manufacturer and supplier of the PEEK brand polymer worldwide.

PEEK is a trademark of Victrex.

Particulate fillers in polymers continue to play a very important role and a book provides a guide to the fundamentals and has a chapter covering the latest developments in nano-filler technology.

The use of particulate fillers in polymers has a long history, and they continue to play a very important role today. The aim of Rapra's new Handbook, Particulate-filled Polymer Composites, Second Edition, is to provide a guide to the fundamentals of the use of particulate fillers, which is accessible to people from the many different industries and disciplines who have an interest in the subject. In the relatively short time since the publication of the first edition in 1995, much has changed and all the chapters have been updated and revised, and a completely new chapter covering the latest developments in nano-filler technology is included.

Particulate-filled Polymer Composites begins by considering the selection and use of particulate fillers, including factors such as cost, purity, particle size and shape, and density.

This is followed by discussion of the different types of particulate filler, the characterisation of filler surfaces and their modification.

The current practices for preparing particulate filled polymers are described, as are characterisation of the compounds and the relationship between compounding route and material properties.

The use of particulate fillers in specific classes of polymers (elastomers, thermoplastics, and thermosets) is described.

Effects of other additives, the properties of the filler, and the performance, processing and application of the filled polymer are considered.

The author, Roger Rothon, is now an independent consultant, specialising in the production, surface modification and application of particulate fillers for polymer composites.

He previously worked for ICI for over 25 years, where he was responsible for several new product developments, including new types of coupling agents for silica and calcium carbonates and novel conductive and magnetic fillers.

After leaving ICI, he was Technical Manager for Flamemag International, where he led the development of a new process for the production of magnesium hydroxide flame retardant fillers.

In 1996 he was made a visiting Professor at the Manchester Metropolitan University, where he is now involved in research on filler surface modifiers.

Hardcoated in-mould decoration films simplify the production process by reducing the number of manufacturing stages and streamlining part production.

Autotype International has launched a new family of hardcoated films designed to meet the growing plastic component demands of the automotive industry, while helping to reduce both costs and lead times. The new Autoflex In-Mould Decoration (IMD) films simplify the production process by reducing the number of manufacturing stages and streamlining part production. The hardcoated films are reverse printed, formed and cut to shape before being back injection moulded.

Developed for shallow, medium and deep-draw IMD applications, Autotype's new films provide the perfect solution whereby intricate graphics can be reproduced on 3D components, such as HVACs, PRNDLs and other automotive interior parts.

The four films that make up the range have been individually designed to provide a variety of options, enabling end users to specify the film that best meets the demands of different applications.

The range includes Autoflex EBG, which is ideal for cost-effective embossing and shallow-form applications; Autoflex AutoForm, best suited for gently-formed parts where micro-cracking must be avoided; and the innovative Autoflex HiForm and robust Autoflex XtraForm films.

HiForm features an ingenious self-healing coating that repairs itself when scratched and is ideal for parts that require a medium depth of form with simplicity of processing, whilst Autoflex XtraForm is designed for deep form applications where maximum draw and extra hardness are required.

The Autoflex IMD range delivers all the design and cost advantages associated with other forms of IMD technology, but also offers a number of additional benefits, including high levels of abrasion resistance for component parts likely to be exposed to excessive wear and tear, and the ability to be used for backlit components or where complex or photographic quality graphics are required.

Perhaps as importantly, as Richard Townsend, Product Manager at Autotype, explains, 'Unlike first surface In-Mould Decoration or the use of uncoated films, Autoflex IMD is an extremely economical technology, offering low unit costs due to savings both in tooling costs and reductions in the number of moulding, assembly and finishing processes and materials required.'

PBT plastics allows a user to mould an airflow sensor body in one piece without annealing - saving two production steps, when compared to alternative materials.

Hitachi Automotive Systems Europe has selected a reinforced Arnite polybutylene terephthalate (PBT) blend from DSM Engineering Plastics for injection moulded mass airflow sensor body destined for Audi engines. Arnite TV4 261 30% glass reinforced grade PBT provides a combination of properties important to the application, including excellent flow, long term dimensional stability, stiffness and strength over a wide temperature range and chemical resistance. Production requires only moulding - no annealing is required to relieve internal stresses that could lead to warpage.

'Throughput is excellent with this design,' said Andrew Bridge, procurement and design manager for Hitachi.

'The ability to mould the unit in one piece without annealing saves us two production steps compared to less sophisticated, two-piece approaches with alternative materials.' The Hitachi body serves both to mount the mass airflow sensor system precisely and to shape air flow using a moulded-in grid.

To control the turbulent airflow, the grid induces a laminar flow that helps ensure accurate feedback about engine air intake temperature to the engine control unit.

Mass airflow sensor data help engine control systems maintain an optimum air-fuel balance.

The grid's thin-wall elements and intricate geometry benefit from Arnite's flow properties, minimising moulded-in stresses and strains that later might contribute to warpage or unpredictable dimensional change, causing the sensor to misread airflow.

The design process for the component was a collaboration involving Hitachi, moulder and toolmaker WH Smith and Sons, materials and processing expert DSM Engineering Plastics and design and mold flow specialist DSM/DADC (Design and Development Centre).

* About Hitachi Europe - Hitachi Europe Limited is a wholly owned subsidiary of Hitachi Limited, Japan.

Headquartered in Maidenhead, UK, it has operations in 15 countries and employs 470 people across Europe, the Middle East and Africa.

As a 'Best Solutions Partner' Hitachi Europe tailors its services and solutions to meet the specific needs of its customers.

Hitachi Europe comprises eleven key business areas: power and industrial systems; rail; industrial components and equipment; information systems; high performance computing; digital media; display products; air-conditioning and refrigeration systems; procurement and sourcing; corporate technology group (research and development) and the Hitachi Design Centre.

Hitachi Automotive Systems Europe is headquartered in Horwich, Bolton UK.

* About DSM Engineering Plastics - DSM Engineering Plastics is a business group forming part of DSM's Performance Materials cluster.

DSM Engineering Plastics is a global supplier of Stanyl PA46 and Akulon 6 and 66 polyamides, Arnitel TPE-E, Arnite PBT and PET polyesters, Xantar polycarbonate, Yparex extrudable adhesive resins, and Stamylan UH Ultra High Molecular Weight PE.

These materials are used in technical components for electrical appliances, electronic equipment and cars, in barrier packaging films as well as in many mechanical and extrusion applications.