Injection molder Rennicks Plastics Group, hit by fierce competition, will close in October with a loss of 88 jobs.
Rennicks, based in Kilbride, blames a steady loss of customers to Asia and Eastern Europe.
The company operates 30 injection presses with clamping forces of 22-900 tons at its single plant, which serves the computer, television and medical-device sectors.
Last year the 20-year-old firm, part of Dublin-based holding company Fitzwilton plc, had tried to restructure in the face of intensifying foreign competition, a spokesman said.
The molder's sister company Rennicks Signage, a producer of road signs at the Kilbride site, has been more successful, company officials said.
Rennicks Signage has growing sales in the United Kingdom and the Middle East. It also employs 88.