Carbolite, a manufacturer of standard laboratory and industrial ovens in Hope Valley, U.K., has developed a solution for a leading producer of arterial stents used by clinicians to treat cardiovascular disease.
The stent maker required a custom Class 10,000 clean room oven to meet precise production needs. Although the stents only needed heat treatment to a maximum 752°F (400°C), the oven's dimensions and temperature uniformity specifications posed a major technical challenge. The solution called for a chamber nearly 5' deep to be heated with a stability of better than ±1.8°F (±1°C) under steady state conditions coupled with temperature uniformity better than ±9°F (±5°C). To ensure good temperature uniformity, the oven is divided into three separately controlled zones. The main program controller links digitally to two slave controllers, which automatically track the program set in the main controller.
A digital time-temperature program controller manages the oven temperature and can store up to 20 programs each with up to 16 segments. A program segment relay can be set to sound an audible alarm at the end of the program.
The oven employs forced-air circulation positioned to give optimum zone uniformity. A specially designed load management system also is a key requirement because the stent manufacturer needs to quickly and easily load the untreated arterial stents into the chamber through the “front door” and unload the medical devices through the opposite door within a clean room environment.
Carbolite designed and built a loading system that allows the stents to be loaded onto mandrels for easy transport straight from a carrier on a trolley into the oven chamber, ready for the heating process. The loading system has an adjustable support frame that holds 30 shafts.