HPDC System Optimization and Cost Reduction
Malte Leonhard and Florian Wirth, Flow Science Deutschland GmbH
FLOW-3D CAST offers valuable support for optimizing casting design and system performance. This article examines the filling process during the development phase through two examples. Then a case study from Project Engineering GmbH, a long-time customer of FLOW-3D CAST, demonstrates best practices in die casting technology and the economic benefit that simulation delivers.
Using Metal Inputs to Pre-Define Ingate Positions
Metal inputs provide a powerful method for predefining ingate positions early in the development phase. By adjusting parameters such as position, dimensions, and metal velocity, key objectives, such as reducing turbulence, achieving directional filling, and optimizing evacuation strategies can be evaluated efficiently.
This video demonstrates the filling of a pillar structure with three different ingate designs:
- Versions 1 and 3 exhibit large, entrapped air regions.
- Version 2 achieves a smooth filling process, where two melt fronts continuously fill the casting part.
- Positioning the ingate system in the central structure ensures that air is pushed out through the T-junction, allowing for easy evacuation.
Optimized Runner Design
Another crucial improvement involves optimizing the ingate geometry. The initial design of the runner system for the pillar structure was refined using insights from scientific literature [1], allowing for an optimal cross-section definition along the ingate.
This modification minimizes turbulence and enhances overall casting quality.
Here we see a comparison of pillar structure filling with two different runner system designs:
- Version 1: A wake zone is visible at the latest ingate, leading to air entrapment.
- Version 2: By reducing abrupt cross-section changes along the chord line, air entrapment is significantly reduced.
- The wake zone disappears, and the metal fronts merge seamlessly within the casting part.
Customer Case Study: Project Engineering GmbH Achieves Casting System Optimization while Reducing Cost
Andreas Harborth, Project Engineering GmbH
Project Engineering GmbH successfully applied FLOW-3D CAST to optimize an oil pan cover produced on an HPDC machine.
Initial State:
- Lot size: 60,000 pcs/p.a.
- 100 mm plunger diameter
- Closing force: 1600 tons
- Alloy: EN AC-AlSi9Cu3(Fe)
- Shot weight: 2885 grams
- Filling & solidification time: 26.5 seconds
The end customer requested cost optimization to ensure a 3% price reduction, while maintaining or improving quality.
Optimization Goals:
- Increasing casting cell efficiency
- Reducing recycled material weight (e.g., runner and venting)
- Reducing cycle time
- Minimizing scrap rates & increasing process stability
Key Issues Identified in the Initial Design
- Evaluating the start design, these specific areas were identified as needing improvement: Low fill ratio (23%) – The low fill ratio and plunger speed (0.15 m/s) led to a long first-phase cycle time.
- High casting-to-product weight ratio (2.2:1) – Excess material required recycling, increasing closing force demand and solidification time.
- High scrap rates – Entrapped air caused excessive porosity, highlighting the need for improved venting strategies.
Improvements Achieved with FLOW-3D CAST
By redesigning the casting system and filling strategy, significant performance and economic improvements were realized:
- 165% increase in revenue – Process efficiency allowed for a higher overall yield from ~€38,000/a up to ~€100,000/a.
- Smaller casting machine usage – A reduced projected area decreased the necessary closing force to 1200 tons, cutting machine and time costs.
- 62% reduction in volume porosity – Optimized venting and gating minimized turbulence and improved air evacuation.
- 14% reduction in casting weight – Total shot weight was reduced from 2885 g to 2470 g. Lower material consumption led to energy savings during melting.
- 10% cycle time reduction – First first-phase filling was shortened. A faster solidification time was achieved through several design and process changes, including a smaller plunger diameter, which reduced the thermal modulus. With the part ejection 6 seconds earlier, the output can be increased by +7 pcs/h.
The overall casting quality improved by 50%, meeting customer specifications for leakage and pore size. This resulted in a direct increase in output and profitability, ensuring the requested 3% price reduction, while still boosting margins by 165%.
The videos above compare the filling behavior of the initial base design and the final optimized design.
The first video illustrates the velocity magnitude during the filling stage; the second video shows the entrained air. In the base design, several flow challenges become evident.
- The first phase takes significantly longer, leading to a delayed transition to the next phase.
- At the transition point, visible melt splashes appear in the runner arms, causing disturbances in the flow.
- During the second phase, large wake zones form between the ingates, trapping air pockets that are difficult to evacuate.
The final optimized design demonstrates a much faster and more controlled filling process.
- The modified runner system enables a seamless melt front, pushing air efficiently into the venting system.
- This improvement minimizes entrained air and reduces the risk of gas porosity.
- These effects lead to a more stable and uniform fill, which can be clearly observed in the animations for the optimized design.
The Benefits of FLOW-3D CAST in High Pressure Die Casting Optimization
This case study demonstrates how FLOW-3D CAST provides a data-driven approach to process improvement, even for existing cast parts. By analyzing key variables such as entrained air, solidification time, and pore size, manufacturers can quantify and enhance process quality and performance.
Would you like to see how FLOW-3D CAST can optimize your casting process? Get in touch with us today!
References
[1] Nogowizin (2010) Theorie und Praxis des Druckgusses