Challenge

A leading machine tool accessories manufacturer in India assembled torque motors for Bio-Directional Tool Turret, where very high torques are induced. During the assembly, the rotor was fit on to the shaft with heat shrink method and stator was fit to housing with heat shrink with a high interference. These motors develop temperatures of 120 °C continuous. Shrink fit of assemblies involves heating costs and time, additional labor and lower reliability and customer wanted to improve on these.

Solution

Loctite 648 is high Strength, low Viscosity Anaerobic Retaining Compound with fast fixture of 5 minutes and resists temperatures up to 175 °C. It was recommended to use Loctite 648 with up to 10 micron clearance.

• Due to the high cured strength over a wide range of gaps, Loctite retaining compounds allow the usage of clearance or light press fits - thereby eliminating the high costs of precision surface finishes and close tolerances between mating parts.
• Eliminating the processing costs involved in producing the press or shrink fits by avoiding using expensive machines such as presses, grinding / honing machines and heaters.
• Filling into the micro gaps & surface irregularities ensures 100% surface contacts.
• Consistency of load carrying performance is improved even over uncertain tolerances.
• Eliminating the fretting corrosion.

Results

Customer successfully tested Loctite 648 for stall torque test at 120 °C. Customer gained savings of more than 28% on heating costs and labor. The assembly is also expected to last longer due to uniform load distribution, unitized by adhesive and protected from fretting corrosion.