This is the fifth round of job cuts at the Exeter plant in the past year
One of Devon's biggest employers is to cut its workforce by about 200 - one of the single biggest lay offs in the county since the economic downturn.
The jobs are going at Alcoa Howmet in Exeter - a foundry which produces turbine blades.
It leaves the company with about 500 employees - less than half the number it had a year ago.
The company said the cuts were necessary because the market for its products had "dried up".
In a series of cuts last year, 251 workers lost their jobs and in January a further 95 staff were made redundant.
Despite the job losses, Alcoa Howmet has insisted the foundry in Exeter remains an important part of its business.
"Exeter operates a very good facility and has an excellent workforce. It is just that the market is soft at the moment," a spokesman told BBC News.