Luxury car maker Aston Martin faces further industrial action this month.
The Transport and General Workers' (T&G) union has announced dates for more strike action after condemning the company's refusal to negotiate over changes to working practices.
T&G members staged a stoppage last Friday, and have decided to also strike at the company's Bloxham and Newport Pagnell sites on 21 August and 22 August. Production will resume after the weekend.
John Street, T&G regional industrial organiser, said: "We are very disappointed the company is refusing to negotiate over the changes to working practices. Consequently, the union is announcing further strike dates.
"This is the first ever strike at the company, which demonstrates the depth of anger at these proposals. We urge the company to think again."
The dispute is over new shifts nicknamed the 'Martini' shifts, as production workers fear they will be required to work anytime and anywhere the company wants.