Facilities

Investment casting is an industrial process based on and also called lost-wax casting, one of the oldest known metal-forming techniques. From 5,000 years ago, when beeswax formed the pattern, to today’s high-technology waxes, refractory materials and specialist alloys, the castings allow the production of components with accuracy, repeatability, versatility and integrity in a variety of metals and high-performance alloys. Lost-foam casting is a modern form of investment casting that eliminates certain steps in the process.

There are a variety of materials that can be used for the investment casting process, including stainless steel alloys, brass, aluminum, and carbon steel. The material is poured into a ceramic cavity designed to create an exact duplicate of the desired part. Investment casting can reduce the need for secondary machining by providing castings to shape.

The process is generally used for small castings, but has been used to produce complete aircraft door frames, steel castings of up to 300 kg and aluminium castings of up to 30 kg . It is generally more expensive per unit than die casting or sand casting, but has lower equipment costs. It can produce complicated shapes that would be difficult or impossible with die casting, yet like that process, it requires little surface finishing and only minor machining.

Centrifugal casting or rotocasting is a casting technique that is typically used to cast thin-walled cylinders. It is noted for the high quality of the results attainable, particularly for precise control of their metallurgy and crystal structure. Unlike most other casting techniques, centrifugal casting is chiefly used to manufacture stock materials in standard sizes for further machining, rather than shaped parts tailored to a particular end-use.

In centrifugal casting, a permanent mold is rotated continuously about its axis at high speeds (300 to 3000 rpm) as the molten metal is poured. The molten metal is centrifugally thrown towards the inside mold wall, where it solidifies after cooling. The casting is usually a fine-grained casting with a very fine-grained outer diameter, owing to chilling against the mould surface. Impurities and inclusions are thrown to the surface of the inside diameter, which can be machined away. Casting machines may be either horizontal or vertical-axis. Horizontal axis machines are preferred for long, thin cylinders, vertical machines for rings. Most castings are solidified from the outside first. This may be used to encourage directional solidification of the casting, and thus give useful metallurgical properties to it. Often the inner and outer layers are discarded and only the intermediary columnar zone is used.

Often times a metal part that is cast will require finish machining of certain details on the casting. Some methods of metal casting such as investment casting and die casting are more accurate than other methods, but typically there are certain tolerances or geometry that can not be cast and must be machined. It is common for a casting foundry to apply a machining allowance to their cast parts to allow for finish machining to final size.

Machining of castings often requires different clamping or locating techniques to minimise errors from variations in the castings themselves. We, Casting machining specialists understand this and create location strategies to ensure consistent results.

BAC has a separate machining unit with 20+ CNC machines and 15+ conventional lathes.

From the raw material to final casting products, we monitor every process to ensure top quality results.

  1. Raw Material Quality Control: Raw material bought is checked for chemical and physical property as per the product requirement.
  2. Production quality control: Working instructions are given to the workers before the process beginning. The sample.
  3. We will check the chemistry again when the products are finished. We also check the mechanical property, such as tensile strength, yield strength, elongation and hardness.
  4. To find the inner defect, we also use non-destructive method to check the products, such as ultrasonic testing and radiography inspection. To find the surface crack, the magnetic particle testing and penetrating testing are also done.
  5. We keep the records atleast for 5 years, which we use to trace every batch.
  6. Experienced inspection team of Casting Quality, conducts the entire quality control procedure from raw material to finished products. All inspectors are well trained and have rich product knowledge & inspection experiences.

BAC has all the necessary facilities for

  1. Raw Material Control.
  2. Chemistry Spectrum Analysis.
  3. Mechanical Property.
  4. Metallographic Analysis.
  5. Ultrasonic Testing.
  6. Magnetic Testing.
  7. Radiographic Testing.
  8. Dimension Inspection.
  9. Visual Inspection.
  10. Penetrant Testing.
  11. Leak Testing.
  12. Hardness Test.

Rollover furnace is used in investment casting applications where precise and repeatable pours are important.

    Advantages
  1. Precision melting and pouring with high frequency induction power for high quality, high alloy investment castings.
  2. No ladle or hot metal transfer.
  3. Fast mold filling.
  4. Inert atmosphere melt covers availableHydraulic rollover at adjustable speeds.
  5. Hydraulic operated mold clamp with precise pressure adjustment.
  6. Consistent pouring - mold after mold.
  7. Mold pressurized during pour cycle available.