The difference between reduced pressure and conventional electron beam welding is primarily in the design of the electron gun. Novel gun design allows the process to be carried out at a rough vacuum level, or reduced atmospheric pressure, of around 1mbar compared with 10 -5 - 10 -2 mbar for conventional EBW. The technology was initially developed by Allan Sanderson at TWI in 1992 and has undergone continued development since this time.
A major benefit of the reduced pressure requirement is the ability to function with local seals or vacuum arrangements rather than a traditional vacuum chamber. Thus, large structures are now viable for EB welding.
Set-up and pump down times for RPEBW are up to 3 times quicker than conventional EBW allowing better utilisation of equipment and higher throughput. One further economic benefit is the lower capital purchase cost when compared to conventional EBW as a large chamber and high performance vacuum pumps are not required.
TWI has obtained patents for this technology in Europe, USA, Japan and a number of other countries (EP1018137, US6404115 & others).
The patents cover the method and equipment of RPEB, so anyone using the process needs permission (licence) from TWI.
TWI is pleased to offer non-exclusive licences to any potential users on reasonable commercial terms. Special arrangements are available for machine manufacturers, research institutes and universities.
For further information concerning licensing, please e-mail contactus@twi.co.uk.