1. What is meant by Casting? Ans: Casting is the manufacturing process where the molten metal is poured into a mold and allowed to cool and solidify. The solidified part is also known as casting, which is ejected or broken out of the mold to complete the process. Casting is a multipurpose process that offers exceptional freedom in forming complicated components. It is also conducive to high-volume production runs, where the material quantities can be efficiently controlled to minimize waste and reduce cost. The process of casting is also known as founding. Casting is most often used for making complex shapes that would be otherwise difficult or uneconomical to make by other methods.
2. What is an Investment Casting? Ans: The term “investment” may bring dollar signs before the eyes of those who are not familiar with the process. Actually, Investment refers to the ceramic materials that are used to build a hollow shell into which molten metal is poured to make the castings. The origin of the term investment comes from the solid mold process where a plaster type material is poured or invested into a container that holds a clustered tree of small plastic patterns that are identical to the casting being produced. Once the ceramic material is hardened, its internal geometry takes the shape of the casting. The wax is melted out and molten metal is poured into the cavity where the wax pattern was. The metal solidifies within the ceramic mold and then the metal casting is broken out. The wax models are engineered to be slightly larger than the casting due to the volumetric shrinkage of metal when it cools from a liquid to a solid.
3. Why it is called as Investment Casting? Ans: According to us investment refers to the process of the ceramic slurry application. There are two main techniques to enclose wax patterns in the high temperature ceramics which eventually become the mold to hold molten metal. In other way by pouring ceramic slurry around a wax tree assembly that is inside a container, and the second is to dip the wax into the slurry to apply the slurry in layers. When any object is dipped into a liquid, and that liquid stays on the surface, which is called investing.
4. What Kinds of parts are suitable for Investment casting? Ans: The beauty of the investment casting process depends on the design freedom process affords of our engineers and designers. Due to its complex shapes, tight dimensional tolerances, excellent repeatability from part to part, excellent surface finish and a wide variety of alloy choices make investment casting a very cost effective solution to complex manufacturing challenges. The old and most common applications for investment casting that are familiar to include class rings and jewelry, knee, hip and other bio-implants, metal golf club heads and putters, rocker arms in internal combustion engines and the turbine blades in jet engines.
5. What alloys can be poured as an investment casting? Ans: All the ferrous and non-ferrous materials can be called as investment cast. When the alloy is facing ferrous side then, carbon, tool and alloy steel along with the 300, 400, 15-5HP and 1 7-4PH stainless steels are most commonly poured and most of the aluminum, copper base, and other non-ferrous materials can be cast. Moreover there are super alloys used primarily in the gas turbine industry to produce blades and vanes. These alloys are usually composed of nickel and cobalt with a variety of secondary elements added to achieve specific strength, corrosion, and temperature resistant properties.
6. Why should we consider using investment castings? Ans: Because the investment casting process offers many benefits including cost savings, design freedom, close tolerances, better finishes, and savings in machining time, reproducibility, and assembly savings. The below mentioned are few benefits why we consider using investment castings.
- Low initial tooling costs
- Elimination of material waste
- Design flexibility and capability
- Design enhancements
- Accurate and Consistency
- Close Tolerances
- Surface Finish Improvement
- Amortization Lowers Tooling Cost
- Better for the Environment
7. What size range of parts can be produced by the investment casting process? Ans: Investment castings can be produced from a fraction of an ounce to over 1000 pounds. Most of the investment casting foundries only cast up to 20lbs. The distribution of the weight of a casting can have an effect on if a component can be investment cast due to the need to gate and feed the casting. Presently a large number of foundries are increasing their capacity to pour larger parts and pieces between 20 – 120 pounds. If you’re unsure or you have any questions about our capacity contact us at md@moderninvestmentcast.com
8. What size range of parts can be produced by the investment casting process? Ans: Advantages and Disadvantages of Investment Casting
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Advantages |
Disadvantages |
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Complex shapes which are difficult by any other method are possible |
Time consuming as shell molds cannot be reused |
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Very close tolerances and excellent surface finish can be obtained |
Expensive as many labor involved in the preparation of the wax patterns and shell molds. |
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Ready for use with little or no machining required |
The size of the casting is often limited |
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Almost any metal can be cast |
Occasional minute defects |
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No flash or parting lines |
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Suit for producing complex shapes where other manufacturing processes are too costly and time-consuming |
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9. Aren’t Investment Castings expensive? Ans: While investment castings are usually more expensive than other casting processes and forgings, investment castings greatly reduce the overall cost of a metal component by reducing the amount of machining or welding and material waste that may occur. While investment castings are normally extra exclusive than fictitious parts or those produced by other casting methods, they make up for higher cost through the reduction of machining achieved through the near net shape firm tolerances that can be held as cast. Many parts that require milling, turning, drilling, and grinding to finish can be investment cast with only.
10. What type of Tooling is required for Investment Casting? Ans: While Lost wax injection tooling is a critical key element of what makes investment casting the unique foundry process. These injection dies are used in high pressure molten wax presses at our facility to produce dimensionally accurate, high grade solid wax patterns, which form the basis for the next critical step of ceramic mold building, so they must be designed for ease of use, maximum efficiency, and durability.
- Wax pattern tooling
- Soluble wax tooling
- Ceramic coring tooling
11. How does Investment Casting compare to the alternative production methods? Ans: According to us Investment casting can be compared to different alternative such as Machining, MIM, Sand Casting, Forging, Die Casting for different such production methods. Our Investment casting is related with the complex design and geometries that are not possible for forging are all possible with investment casting. Although the latest technology machining equipment makes it possible to produce complex geometry parts, investment casting is always favorable for unit price in terms of high-volume demand and delivery duration.
12. What leadtime can you expect for an investment casting? Ans: Once a part is approved for production, our lead-time is 8 weeks. There are times when our clients just don’t have the luxury of a standard delivery, so please contact us in such cases, so we can reduce this lead-time to meet your requirements wherever possible.
13. Why would I use an Investment Casting? Ans: Whether it involves aluminum, stainless steel or other alloys, our lost wax investment casting process can offer a cost effective and efficient solution in the following ways:
- Design flexibility and near net-shape capability
- Excellent repeatability and dimensional control
- Wide variety of casting alloys
- Economical use of costly alloys
- High strength and durability
- Improved appearance over elements, forgings and sand castings
- Excellent surface finish (typically 60 – 100 RMS)
- Potential weight reduction
- Part count reduction and minimize assembly operations
- Reduce secondary machining
- Cast in part numbers, logos and other identification
- Cost effective tooling
- Cost effective alternative to forging and die casting in lower volumes
14. Do you have the capacity / capability for large and / or small production? Ans: YES, we create high quality, flexible and economical solutions to customer demands from hundreds to hundred thousands pieces. Our pride itself is meeting your specific requirements and deadlines.
15. How can I be certain that Investment Casting is the correct process for my product? Ans: Your first step is to call Modern Investment Cast Industries and discuss the application, design, material and quantities with our manufacturing personnel. We can make design and material recommendations to improve the cast ability of the part to improve its suitability for the IC process. If desired, then next step could be to produce a prototype casting using additive manufacturing technology to create a consumable pattern in lieu of a wax pattern. Using Rapid Prototyping technology to create a sample part is a low risk opportunity to prove your design using investment casting. After testing and evaluation and perhaps even several generations of prototypes to perfect the design a production tool can be built to make the castings in larger quantities and at a lower piece price.
16. What kind of surface finish should I expect if I don’t need to machine the parts? Ans: Since the ceramic shell is built roughly smooth patterns shaped by injecting wax into a polished aluminum die, the resulting casting finish is excellent. Typically, a 125 micro finish is standard and even finer finishes can be obtained through common metal finishing operations such as blasting, polishing, or electro polishing. Sometimes a customer will have its own standards for surface blemishes (positives, negatives). These are discussed and agreed upon with the customer based on the function and cosmetic requirements of the part prior to release of the tooling order.
17. What information should I provide for a quotation? Ans: For a clear, precise and timely quotation; we request, if possible:
- 2D technical drawing
- 3D model data
- Casting material / alloy information
- Yearly demand quantity and delivery lot-size
- Specific quality requirements / standards