The firm said the losses were necessary for the factory's future
One of Exeter's biggest employers is set to make 95 people redundant.
Turbine blade maker Alcoa Howmet blamed the recession and said the losses were to ensure the long-term future of its plant which employs 786 people.
Consultations were under way with the unions and the company said it would work with them to minimise the impact on employees.
It follows the announcement of a series of jobs cuts in 2009, 95 in October, 86 in April and 70 in July.
A spokesman for the US firm said: "The decision to reduce the operations' employment is in no way a reflection on the many skilled and dedicated employees at this plant.
"While Alcoa Howmet Exeter management recognizes the impact of these proposed measures on the workforce, this action is necessary to ensure the long-term viability of the plant."
The Alcoa Howmet foundry on the Sowton industrial estate in Exeter has been manufacturing turbine blades for the aerospace and power generating industries for about 40 years.