This induction-based shrink-fitting process was fast, energy- and cost-efficient and produced consistent, repeatable results, independent of the operator skills. It was a process completely safe for the operator and safe for the environment, with no fumes or noxious emissions due to the lack of open flame.

The time-, energy- and cost-efficient induction shrink-fitting for an aluminum assembly used for medical purposes has recently been demonstrated by UltraFlex Power Technologies. Being a leading manufacturer of advanced, digitally-controlled induction heaters, UltraFlex was contacted by a medical device manufacturer looking to optimize a shrink-fitting process using induction. The customer was looking for a test setup that would demonstrate the required induction heating equipment, heating parameters and results to be expected from an induction-based shrink-fitting.

For this test application, the customer had supplied an aluminum medical assembly with dimensions 6.86 cm x 4.06 cm x 7.62 cm (2.7"W x 1.6"L x 3"H) and thickness 0.135 cm (0.053"). He required that the top section of the aluminum can be heated at a temperature of 260°C (500°F) to allow for shrink-fitting. The targeted heat cycle was 10 seconds or less.

For this heating scenario UltraFlex engineers used an induction equipment from the UltraFlex UltraHeat SM series, as well as a square induction coil. UltraHeat SM are compact and easy-to-use 5kW induction heaters which can be used with either a water-cooled or air-cooled remote heat station. They feature adaptive digital phase control providing efficient operation in a wide frequency range.

To confirm the reach of the desired temperature, a tempilaq paint was used in the heated zone.

At a power of 4.88 kW, the target temperature of 260°C (500°F) was achieved within mere 15 seconds and the part was successfully shrink-fitted. UltraFlex engineers confirmed that the use of a custom coil would allow for further optimization of the heating time, thus meeting the heating cycle target time.

This induction-based shrink-fitting process was fast, energy- and cost-efficient and produced consistent, repeatable results, independent of the operator skills. It was a process completely safe for the operator and safe for the environment, with no fumes or noxious emissions due to the lack of open flame. The customer was presented with all required parameters to optimize this heating process via induction heating.