Objective: Industrialisation, casting and stress simulation of a component of a kitchen exhaust hood
Product: Motor unit element; alloy: AlSi9Cu3 (UNI EN AB 46000)
Process:  Cold-chamber die-casting
Requirements: Buckling verification of the “legs” and ensuing compliance with fixing centre distance

The action

The action consisted of six phases. In the first phase, we compared the 3D drawing with the 3D drawing in order to assess the industrialisation process. In particular, we analysed various elements: the radiuses, the drafts, the tolerances, the parting lines and the shearable burrs.

We then went on to phase 2: analysis of the sprue. In terms of filling, no significant problems were observed, the metal filled the part evenly. Air pressure peaks were observed, however, due the high speeds in the farthest areas the melt entered. To solve these problems we added vents, adjusted the parameters and slowed the speed at the gates.

In the next phase we worked on the design of the mould and on the heat regulation and cooling circuits. Once the design was complete, we went on to simulate the real mould. We simulated 9 cycles of die pre-heating so as to achieve as precise a heat range as possible.

One of the critical points was the formation of cracks, namely geometrical discontinuities that can form in die casts at relatively low temperature where the heat concentration of the die is contrasted by the much lower temperature of the mould. The heat-related stresses that originate in these conditions can reach such high values locally as to cause ruptures and, when changes in section are also involved in that area, can probably lead to the creation of cracks.

Our technicians therefore analysed the results obtained from the simulation, with special focus on the areas subjected to more equivalent stress and more prone to the risk of cracking.
The simulated part was analysed and the necessary changes were made. At this point, we were able to move on to the production of the mould in line with the client’s requirements.