New laws are being introduced to enforce sustainable business practices and establish guidelines for future production processes. The advancement of "clean" technologies is both necessary and actively encouraged, gradually replacing traditional standards across various industries. Additionally, energy efficiency has become a key priority for companies looking to lower operational costs.
Lightweight construction plays a crucial role in both the aviation and automotive industries. Optimizing an aircraft or vehicle for reduced weight directly decreases energy and fuel consumption. Aluminum cast components offer significant potential for lightweight design, but a key requirement remains: maintaining or even improving structural stability while reducing weight. This can be achieved by minimizing material usage or utilizing hollow casting techniques with sand cores, followed by core removal. The ongoing push to decrease component weight—and, in turn, lower CO₂ emissions—continues to drive innovation in this field.
Low Pressure Process
The Kurtz low pressure process plays a crucial role in resource conservation. It enables the production of thin-walled parts as slim as 3 mm or less, while also allowing for material accumulation, high mechanical properties, and a reduction in recycled material usage.
Key Factors for a Successful Casting:
- Optimal mold filling through low pressure
- Advanced cooling technology for precise solidification
- Innovative furnace technology ensuring melt protection
- Intelligent, flexible machine design for enhanced efficiency
Key Factor: Optimal Mold Filling with Low Pressure
At the core of the low pressure process is turbulence-free mold filling. The aluminum melt remains protected from external influences inside the furnace. By applying controlled pressure—ranging from millibar levels up to a maximum of 1 bar—the molten aluminum is guided into the mold cavity, typically a permanent die-cast mold, through a riser tube. Once the mold is filled, the outer shell begins to solidify, and the feeding pressure is further increased to densify the casting, ensuring high-quality results.
Advantages of This Process Over Traditional Casting Methods
This method provides several key benefits:
- Purity of Melt – Ensures a cleaner, high-quality molten metal.
- Minimal Turbulence – Enables smooth, turbulence-free mold filling, reducing defects.
- Optimized Material Usage – Dense feeding lowers the need for recycled material.
- Superior Cast Quality – Enhances mechanical properties and overall part performance.
Efficiency and Savings Compared to Gravity Casting
Compared to gravity casting, this process can reduce the need for recycled material by up to 70% (depending on part size), while increasing the output of cast parts and minimizing scrap. Additionally, since compressed air is one of the most expensive resources in a foundry, there is significant potential for cost savings.
The Kurtz pre-pressure technology optimizes air consumption by maintaining a consistent casting starting point, reducing the required air usage to a minimum. Unlike traditional methods, the furnace is not fully vented after each casting, leading to approximately 80% energy savings while also shortening cycle times and improving melt quality.
Key Factor: Cooling Technology
While air is traditionally used for cooling, its inefficiency and high costs have led to a growing preference for water cooling. This method offers superior efficiency and cost-effectiveness. Additionally, temperature- or time-controlled cooling ensures that cooling is activated only when necessary, preventing excessive or improper cooling.
To maintain consistent cooling quality, regulated cooling circuits are used instead of merely controlled ones. This process-optimized cooling system enables controlled solidification, resulting in a fine-grained cast structure. Water cooling not only enhances casting quality and reduces cycle times but also cuts energy costs by approximately 64%.
Key Factor: Furnace Technology
Selecting the right furnace technology is crucial for efficient casting. Large, highly insulated crucible furnaces with capacities ranging from 600 to 4,000 kg enable long, continuous casting and allow for the use of multiple riser tubes due to their spacious pitch circle. This flexibility ensures that riser tubes can be precisely positioned for optimal mold filling and feeding, especially in cases of large or multi-cavity molds.
By utilizing direct gating through a riser tube, complex gating systems and costly feeder boxes can be eliminated. This significantly reduces recycled material and minimizes downstream processing steps such as sawing and grinding. To maintain a stable and consistent mold temperature, the furnace is switched while the cast part solidifies, eliminating the need for additional start-up parts to preheat the mold.
The exchange furnace concept streamlines operations by handling furnace filling and melt treatment outside the casting machine. This minimizes machine downtime and enhances overall equipment effectiveness (OEE). Additionally, the "in-line" filling method, where molten metal is transferred directly from the melting furnace into the casting crucible furnace, reduces internal forklift traffic and allows the melting furnace temperature to be lowered by up to 40°C, leading to substantial energy savings.
Once filled, the melt undergoes treatment directly in the crucible furnace, ensuring superior melt quality. By sealing the crucible furnace with a riser tube cover, the processed melt remains in a protected atmosphere, further improving energy efficiency and reducing overall operational costs.
Key Factor: Intelligent and Flexible Machine Design
Ribbing plays a crucial role not only in lightweight construction for cast parts but also in mechanical engineering, helping to reduce moving masses and enhance efficiency. When combined with an intelligent control system, this design approach maximizes operational performance. Following the principle of “better data – better decisions,” the advanced machine control system allows operators to respond quickly and maintain high efficiency in series production through precisely controllable processes.
Seamlessly integrated with data management systems, the quality management process documents every individual casting, ensuring full traceability. This data serves as both the “birth certificate” of each cast part and a valuable resource for process optimization. By leveraging intelligent data handling, manufacturers can reduce scrap rates and significantly improve Overall Equipment Effectiveness (OEE).
All these advantages clearly demonstrate that low-pressure die casting technology offers an exceptional solution for making the casting process more sustainable. It not only reduces production costs while maintaining flexibility but also conserves valuable resources such as energy and water.
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