Cold Forging of a Silent Block Bush Steel Sleeve

Minimize physical prototypes and reduce waste, while reducing the lead time and overall production costs

ABSTRACT

The object of this study was simulating and optimizing the cold forging process for a silent block bush steel sleeve. A block bush consists of two concentric steel sleeves with rubber securely bonded between them to fill up the void and absorb torsional, axial and radial loads. Silent block bushes are typically used in suspension systems in the automotive industry to absorb load and minimize suspensions. A silent block bush is traditionally used in the linkage system of a car suspension, in railway carriages and in agricultural machinery.

There were multiple objectives attached to this study. Specifically:

• optimize the material flow inside the dies and predict defects such as folds, cracks and underfills
• calibrate the press kinematics
• verify compliance with the original design blueprint
• estimate the maximum forging load at each forging stage
• and all of these while minimizing the costs and lead time

The Cold Forging Simulation Results

The objectives above were all met by the simulation, and the results are best expressed in the words of Gianfranco Marcandella, R&D technical lead at Altia Fontanafredda S.r.l. 

"Thanks to ColdForm™ we achieved multiple objectives: irregular behavior (folds) in the material was identified; the structural integrity of the component after the whole manufacturing process was verified; and the die geometries were optimized for compliance with the design blueprint for the part. We also calculated the total forging load at each of the forging stages which allowed us to choose the most suitable press for the job. Finally die wear was predicted and optimized, allowing us considerable cost savings due to improved durability. Thanks to the guidance and training from the EnginSoft engineers, we were able to learn more about the simulation results allowing us to minimize physical prototypes and reduce waste, while reducing the lead time and overall production costs"

Gianfranco Marcandella
R&D Technical Lead,
Altia Fontanafredda S.r.l.