Induction Shrink fitting

Application: Shrink fitting

Industry: Manufacturing

Application Objectives:
The objective was to evaluate the feasibility of using induction heating to expand precision collet assemblies. The customer required a consistent and repeatable process to replace their current underperforming induction equipment with UltraFlex system solution. Specific goals included achieving precise thermal expansion in two distinct zones (Max. temp. 1100 °F and 550 °F), maintaining dimensional tolerances post-expansion, and enabling manual plug insertion during heating.

The challenge:

  • Expand two areas of the collet assembly to precise diameters without changing performance of production parts.
  • Accommodate manual plug insertion and real-time adjustments.
  • Ensure uniform heating on rotating parts.

Equipment:

Materials:

  • Part: Cylindrical collet with tapered ends and slotted perimeter
  • Material: 4340 steel (magnetic)
  • Heated zones: ~1.0 inch each

Key Parameters:

  • Temperature Targets: 1100 °F (section #1) and 550 °F (section #2)
  • Heat Cycle: 30-60 seconds
  • Completely manual operation
  • Power Settings: 5-16 kW (variable by zone)

Process:
The application involved heating two zones of a 4340-steel collet assembly while the part was rotating on a turntable. A helical coil with specific geometry was used to localize heating. The first heating cycle brought the smaller collet diameter to 1100 °F, followed by air cooling. A second cycle heated the same section to 550 °F for dimensional stabilization. A similar process was attempted on the larger diameter side.

Results and Conclusions:
The UltraFlex SOLO-16 system successfully demonstrated precise control over localized heating in shrink-fitting applications. The customer confirmed that the thermal cycle and part handling met production requirements. The solution offers higher power output, consistent heating zones, and improved control compared to their previous system, justifying investment in the new equipment for higher productivity and precision.

Reference Info: AR 3463-8854

Induction Shrink fitting
Shrink fitting
shrink fitting

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