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Article Series - Part 3 4 Challenges in Aluminum High Pressure Die Casting: Technologies
This article series is dedicated to the changes and developments in the aluminum high pressure die casting industry. The third chapter deals with new technologies, as one of the four challenges, and productivity improvements.
Due to the serious changes in the area of the product portfolio, as well as the increased pressure of cost optimization, technological developments are absolutely necessary.
The requirements that define this for the foundries are enormous. In terms of time, the situation gives no room to move. At the same time, new products must be designed and industrialized at short notice, as well as new processes developed or at least further developed.
A high demand for foundry expertise resources and financial resources is needed in the short term and is also needed in the medium term. This results in the following relevant short-term fields of action:
- Salt cores
- Vacuum die casting
- Minimal lubrication
- Heat treatment
- Alloy development
- Additive manufacturing process (currently only interesting for prototype development)
Based on the long-term corporate strategy and the individual know-how level of the foundries, technology roadmaps have to be created and prioritized.
Partnerships with customers, suppliers, universities as well as market companions can save time, money and resources and make the necessary difference at the end of the day. The following tasks are on the agenda:
- The technology roadmap has to be prioritized and focused.
- JV / partnerships should also be aimed at technology topics (foundry clusters).
- The financial base needs to be stabilized. Financial resources are to be secured in the long term.
- The need for foundry know-how must be secured.
- Profitability remains the top priority, regardless of all other projects.
Salt Core Technology
The salt core technology has been around for a long time. The right breakthrough, however, has so far failed. For a long time, the closed-deck cylinder crankcases were considered a promising future application. However, e-mobility will limit the costly development of this application.
The use in the growing market of chassis and structural parts is conceivable. However, current technology advancement for these parts is unlikely at this time due to other key issues.
Vacuum Die Casting
Air inclusions can be reduced with vacuum die casting. This makes vacuum die casting particularly suitable for crash-relevant components. Furthermore it is a requirement for the necessary heat treatment of the structural components. Last but not least vacuum die casting enables improved mold filling for thin-walled components. Vacuum die casting can be realized in a meaningful and efficient way by means of cooperation or joint ventures with suppliers.
With the further increase in component requirements (mechanical properties, weight, wall thickness), thixocasting and rheocasting have become significantly more important. Worldwide, work is being carried out on various developments, especially in rheocasting. The main goals of further development are above all cost and process optimization. In the long run, SSM casting will play a significant role in highly stressed parts. Cooperations with universities or colleges can also help companies to gain more SSM casting know-how.
With the use of minimal lubrication water consumption including wastewater is reduced. In addition, the cycle times can be significantly reduced and the mould life increased. Improved process reliability and quality are particularly important for chassis and structural parts.
In principle, die cast parts are considered to be difficult to heat treat. Vacuum die casting is an option for heating cast parts to higher temperatures. The industrial process of heat treatment is used to change the physical and sometimes also the chemical properties of a material.
For example crash-relevant components of the vehicle body with strains of more than 10% must be heat-treated. The aim of the heat treatment is to adjust the tensile strength and elongation to the required part requirements. On the one hand, the heat treatment increases the foundries value chain, on the other hand, the technology (for example warpage of the castings) should not be underestimated.
Alloy development is one of the key challenges in the development of chassis and structural parts for the casting process. The components have high requirements for elongation at break, yield strength and tensile stress. The casting process requires a basic castability (long flow paths), long die life and a calculable shrinkage after demoulding the castings. The cast parts must be heat treatable (T6, T7) and may distort as little as possible there. In the final assembly, the parts are then often glued or welded.
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The technology fields have top priority in the short term. Only foundries with expertise in these issues will benefit from the booming market of changing product portfolios. In the medium term, productivity improvements with these technologies are of existential importance.