Foundry Design Influences

The process of drawing up the design should ensure the best possible mould design, for production of high quality of casting. This process should be done in least possible time and cost and give the maximum output from the given resources. The design should study the casting and technology used for making the casting.

Previous experiences and hit and trial methods are not suitable for making a new casting design or solving casting problems are these methods are slow, expensive and require a lot of effort. Usually wrongly located feeders and runners result in most of the casting defects faced. Computer simulation and X-ray videography are a better solution for drawing up new design or solving defects.

Computer simulations help reduce the time required in drawing up sample castings, reduce the cost of making moulds physically and costs associated with modifying the physical moulds, reduces scrap. It also help in designing and modifying the castings according to the customer needs so as when the final physical model is made, it is as per the customer liking and thus wastage in case of rejections are avoided.

Other benefits of computer simulation are: -

• A three dimensional model of casting is made which shows exact location proposed for feeders and runners.
• A step-by-step study of processes can be made by combining images of various sections and of the full casting
• In case there is a need for any modification in the original plan for casting, it can be made easily any number of times. Also a record at each step, before and after modification can be made.
• Since the design can study the proposed placement of feeders, hence the use of metal can be reduced by exact positioning of the feeders.
• Predictions can be made if shrinkages are expected.
• Allows the best possible adjustments to feeders and runners before the castings are finally made.
• In case any unforeseen problem occurs, computer simulation helps remove those problems by making a model and study of the same for problem removal.

Computer simulations go a long way in helping improve efficiency in use of energy. The cost of installation of a computer simulation system, complete with software, training etc may be around $ 100, 000, not forgetting high yearly maintenance costs. However, a study of two offshore foundries has shown a 20% improvement in efficiency and yield. The results are usually visible in three to eight months.

This technology helps to verify the study made and results drawn by the computer simulations. It helps us study the flow of molten metal through cavities, and hence the most efficient design can be chosen and planned for.

Ceramic filters for molten metal are the best while designing moulds for non ferrous castings. These give a lot of benefits.

Steel foundries usually insulate risers to reduce their weight by one sixth of the original weight. This practice should be followed.

In case the metal can be removed from the casting design supplied by the customer, without compromising the strength, durability etc, it should be considered. This not only reduces the cost in increasing the number of pieces produced per tonne, but also save the energy requirement.

Use of robots for casting, when allowed by the size and type of foundry processes, acts as a great booster in quality of output.the output quality becomes increasingly consistent, the energy usage is reduced, and so is the number of rejections by clients.

This is am emerging technology and considered highly advantageous. It not only decreases costs, but also increases the results, which a design can give. More features can be incorporated in the casting and complex processes can be conducted in a single pour. The output of this process is very accurate and leaves less scrap, which then has to be disposed off. Although introducing this technology is a major technological shift, however, it results in about 30 % energy usage reduction, increase in yiely by three to four times and longer life of tools.

Where practical, self-anneling may be used in casting design. Through this design, heat treatment can be done away with.

Softwares such as Magmasoft®, Finite Element Solidification Analysis EKK®, CastView®, Pro/Engineer®, Flow-3D®, Unigraphics®, SolidEdge®) can be used for computer simulation and make casting design drawing up faster and simpler.