Reducing the cost is the need of the hour, and the design simplification is one of the effective means. This case is an example of the same where as the customer requirements in terms of volumes have increased and adding capacity at this juncture should be the last option. Hence we explored the possibility of cycle time reduction through simplifying the design.
This part design needs a hydraulic sliding core for a hole (Figure 4a) and the added complication of a submerged core melting in intricate matching areas. Due to this, the die opening and closing needs to be slow, and coupled with the hydraulic core movement, the cycle time was high. There is also a constraint for a multi-cavity design approach.
Removal of the sliding core will be a solution , but there may be chances of high porosity if the solid hole is drilled
Figure 4a - Model of the part showing the cored hole.
Figure 4b - Simulation results without (left) and with (right) the cored hole showing the hot metal areas.
and tapped. This is a mating part of the previous examples, and porosity is a stringent requirement.
Therefore a solidification simulation was carried out to compare the effect of removing the core in terms of porosity location.
Figure 4c - Model of the part without the cored hole.
Even though the result showed a significant shift of the center of the hot metal (which may result in porosity), it was away from the cored hole by more than 10 mm (Fig 4.2). So a new die was developed without the cored hole (Fig 4.3), and the drilling operation was introduced before tapping in the VMC. This has resulted in an overall increase in throughput.
The cost of die was reduced significantly, and PDC machine tonnage is also reduced, resulting in cost savings. Now, with the elimination of core and design simplification, CRP has developed a multi-cavity tool to augment the throughput further.