Airbus settles fettling dust with clean
air solution from Hosokawa Micron Ltd

Leading aircraft manufacturer Airbus places a high priority on the safety and wellbeing of personnel and when Health and Safety assessments identified a requirement to reduce the risk of employee exposure to airborne chromate (paint) dust generated during fettling operations they took prompt action. Responding to concerns over skin contamination and inhalation of chromate dust particles the Airbus Occupational Hygiene team called in expert help that assessed the risks and led to the installation of several new Local Exhaust Ventilation systems throughout the Hawker business.

A multifunctional, Hawker team, set up to oversee all aspects of the development of a recommended clean air solution were involved in the selection of clean air and containment specialist Hosokawa Micron Ltd following tenders for the project.

'Hosokawa Micron engineers worked closely with our team refining and modifying the system specifications to ensure we achieved the optimum solution, these discussions became the catalyst for improvement in our operations which resulted in a very successful installation, which is of interest throughout other areas of the Airbus business.' explained Rae Carroll, Project Engineer, Airbus.

The installation included two downflow booths, one fixed fettling booth, three mobile fettling trolleys and ancillary systems, all designed, manufactured and installed by Hosokawa Micron Ltd and eliminate the need for Hawker engineers to wear personal protective equipment.

Large scale parts manufacturing/assembly
The downflow booths are designed to offer high levels of operator protection and product containment when generating dust during fettling, drilling and deburring of large sections of fuselage or other items not suited to the fixed fettling booth. Each booth is built over and around the fettling jig giving full workable access to the panel or unit to be trimmed or fettled during assembly. The booths offer a working area of 3m safe working depth and 5m internal width and incorporate overhead lighting to provide best working conditions.
                                                                                                                                                           
A uniform, non-turbulent, horizontal laminar airflow is generated behind the operator and flows across the working area into the rear perforated distribution plate, taking airborne dust particles away from the operators breathing zone. The exhaust air is HEPA filtered before being returned into the booth.

Tests show that chromate OELs are now well below UK legal limits with workers undertaking large scale fettling activities no longer needing to wear face masks to do this work. The workers have expressed appreciation for the improved task lighting and enhanced working atmosphere.

Large scale parts fettling
Large scale parts fettling is now undertaken within the 2m wide fixed fettling booth. The booth with a slotted rear extract plenum is designed with a horizontal airflow of approx 2.2m³/s that takes dust particles away from the operators breathing zone.

Dust particles are extracted to an external filter unit with compressed air pulse jet cleaning system. Dust collected by the filter cartridge is collected in an external sealed bin for easy removal and disposal. The system is fitted with pressure drop monitors and alarm indicators to further safeguard the operators from potential exposure to increased levels of airborne particulates.

The fettling booth has been ergonomically designed for ease of use and includes overhead lighting and integral compressed air sockets that enable air-driven tools to be operated in the booth with short lengths of airline. The fully ATEX compliant system also includes vacuum extraction for removal of debris.

Small parts fettling
A transportable solution designed to reduce operator exposure to potentially harmful fettling dust, polishing dust and swarf created in production of painted and non-painted metal parts or panels, the booths create a safe working environment for operators undertaking polishing, drilling or filing activities where airborne particles are generated.

The three 'plug and play' back-draft extracted booths incorporate a two stage filtration system comprising of replaceable panel filter and HEPA filters to H13 grade standard. HEPA filtered air is discharged into the factory working area. Constantly monitored by differential alarm pressure  gauges across the filter to provide the operator with visual indication when a filter is laden with dust and therefore may require cleaning or replacing. A high performance extraction fans ensures a reliable air flow through the booth, even when the filter cells are dirty, maintaining a safe working environment for operators.

Complete with lighting and an integrated Type H vacuum cleaner for the safe removal of swarf or larger filings the wheeled Hosokawa Micron Fettling Trolleys are easily transportable around the workshop.

The LEV project team and the workshop personnel have been pleased with the overall installation which has lead to a substantial reduction in the risk posed by chromate dust. The Hawker business is now ahead of other areas of the business on chromate reduction risk and the project team is now working with other businesses on site to implement the system.

'We are vey happy with the installation, the team from Hosokawa assisted us through the process to ensure we achieved the best solution. Everything was explained in laymen's terms and the team were flexible in the hours they worked ensuring no disruption to our work in the factory; which was a great plus point.' Lucy confirmed.

Environment, Health and Safety Controller, Mark Richards said, 'We were very impressed too with the high standard of the manuals, they are very comprehensive. This has made it easier for the workers to be trained in operation of the booths and the writing of standard procedures.'

Rae Carroll concludes, 'We would recommend Hosokawa Micron Ltd to anyone, the service was brilliant.'

For further information, e-mail: info@hmluk.hosokawa.com or view website: www.hosokawa.co.uk

Composite plain bearings for wind, wave, tidal and solar energy systems

Renewable energy systems, including solar, wind, wave and tidal power, are ideal applications for composite plain bearings.

In solar energy systems, for example, plain bearings are particularly suitable to the operating conditions, which often involve slow swiveling movements with high loads. In addition, plain bearings are also suitable for operation in media such as water (hydro power) and for dry running applications.

The Schaeffler Group has a rapidly expanding range of plain bearings for renewable energy systems. In addition to its Metal-Polymer Composite Bearings range, Schaeffler also recently launched its ELGOTEX plain bearings.

 Metal-polymer composite plain bearings
Schaeffler's metal-polymer composite bearings are particularly effective in oscillating applications, where the bearings achieve a higher basic rating life than conventional bearings. These products are available as bushes, flanged bushes and thrust washers and are ideal for applications where there are very small radial or axial design envelopes.

The metal-polymer composite material provides low-wear sliding characteristics, as well as a high load carrying capacities and high thermal conductivity. Static load carrying capacities of up to 250 N/mm² can be achieved. Composite materials can also be used in water or other media due to its high moisture resistance.
 
Metal-polymer composite bearings are a cost-effective alternative for applications with minimum available space and a comparatively high sliding speed. The plain bearings are available as bushes and flanged bushes, as well as thrust washers and strips. The material can also be easily formed to specific customer requirements for rotary, linear and oscillating movements. All Schaeffler's metal-polymer bearings are lead-free.
 
Three different materials are available in the range: a selection of bearings with maintenance-free and low-maintenance materials E40 and E50. The two material structures are similar: a porous bronze-sintered structure is applied to a steel or bronze backing and impregnated with a special plastic compound. The solid lubricant produces a lubricant film between the sliding surfaces, which provides low-noise operation with a constant low friction coefficient throughout the entire service life of the bearing.
 
E40 bearings are generally maintenance-free, i.e. lubrication is not required over the entire operating life. PTFE and different chemically inert additives are used as the lubricant. E40 is recommended for rotary and oscillating motion applications, as well as for short stroke linear movements.
 
Bearings with E50 are low maintenance, although initial grease lubrication is required at start-up. The sliding layer comprises mainly polyoxymethylene (POM), a high-molecular thermoplastic characterised by its low friction properties, as well as chemical and thermal stability. E50 is a low wear material that has good damping properties and long relubrication intervals. The material is ideal for rotary and oscillating movements and is also recommended for long stroke linear motion applications.
 
Bearings with the E60 sliding layer are maintenance-free foil bearings. These have a lattice structure in which a sliding layer of PTFE and other additives is rolled and sintered. The structure functions both as a backing and a sliding layer. The PTFE sliding layer is on both sides of the foil so that the sliding motion can take place on the inside and outside of the bushes. A further advantage is that E60 can be easily moulded.

ELGOTEX plain bearings
Schaeffler's ELGOTEX® range of plain bushes provides a variety of technical advantages that stem from the product's unique, entwined double-layer design.

Each bush comprises two layers of wound (twisted) material. The inner, sliding layer is made from synthetic fibres and PTFE fibres in epoxy resin, whilst the outer layer comprises continuous glass fibres (filaments) in epoxy resin. This combined, double wound material is stabilised by applying a specific winding angle to the glass fibres, which significantly increases the strength of the bush.

The result is a host of technical advantages, including extreme robustness, compactness and low wear (due to consistent friction levels). In addition, ELGOTEX® plain bushes are lighter than their bronze equivalents.

The bushes are easy to mount and require no further axial location. Due to their dry-running characteristics, the bushes are also environmentally friendly. The bushes are maintenance-free for life, resulting in reduced maintenance costs for the end user.

ELGOTEX® has already proved itself in many customer applications, including those in which high radial loads or high static loads are present. The new bushes are also insensitive to shock loads and edge pressures.

The product is available with integrated seals and is resistant to corrosive media. The bushes also perform well in applications where swivel or axial movement is required. Good vibration damping properties is a further benefit of ELGOTEX®.

INA plain bushes with ELGOTEX® are available with bore diameters from 20-200mm, outside diameters from 24-220mm, and widths of 15-250mm. Custom versions with outside diameters up to 1,200mm are also possible.

For further information on the Schaeffler Group, e-mail: info.uk@schaeffler .com or view website: www.schaeffler.co.uk