Casting is among the oldest manufacturing method. However, modern technology has introduced various specialized casting methods applied in manufacturing today. Each of these processes has unique benefits. When looking forward to having some items manufactured, it’s good to understand the manufacturing process applied. Here is a guide to the various methods of casting in the manufacturing process.
Investment casting
This casting process involves use of a disposable wax pattern to make each cast part. Wax is injected into a mold before removal to coat using refractory material with a binding agent. This involves various stages to build a thick shell. Assembling various patterns creates common sprues. After the shells are hard, the pattern is inverted for heating in ovens to eliminate the wax. Molten metal is poured into shells for hardening into shape following the patterns of the wax.
Afterward, the refractory shell is broken to reveal the finished casting. An investment casting manufacturing plant manufactures power generation, aerospace components like turbine blades, and automotive components. Some of the advantages of investment casting include:
- High-quality surface finish
- Costs non-ferrous and ferrous materials
- Creating thin-walled items having complex geometries
- Exceptional accuracy with precise dimensions
Sand casting
This relies on silica-based materials like naturally bonded or synthetically bonded sand. Sand casing involves finely ground grains of sand packed tightly together to form a smooth molding surface. Casting reduces the chances of cracking, tearing, and other flaws by allowing shrinkage and flexibility during the cooling stage. The addition of clay strengthens sand helping the particles bond closer. Sand casting is ideal for manufacturing automotive parts including engine blocks.
The process of sand casting involves forming a pattern for packing the sand into the cope and the drag. After enough compacting to resemble the pattern, the cope is taken away to attract the pattern. Afterward, additional inserts or core boxes are installed with subsequent replacement of the cope. The metal is poured and solidified before removing the casting for trimming the risers and gates utilized for the pouring process. Any sand and scale that might have stuck are cleaned.
Advantages of casting process include:
- Affordable production costs for low-volume order
- Ability to fabricate huge components
- Casting both non-ferrous and ferrous materials
- Cheap for casting tooling afterward
Pressure die casting
This is a casting method involving molding non-ferrous metals and allows including copper, zinc, aluminum, and tin under extreme pressure. The process involves coating a reusable mold with lubricant to regulate the temperature of the die and to help during ejection of the component. Afterward, the molten metal is ejected into a die under extreme pressure continuously for the piece to solidify.
Rapid insertion under pressure limits any material from hardening before casting. On completion, the component is removed from the die with subsequent removal of any scrap material. Some of the advantages of this process include:
- Limits need for casting machining afterward
- Closer shape and size tolerances
- Exceptional dimensional consistency of the component
Metal injection molding
This type of injection molding is ideal for tiny precision components that would be costly when manufactured through other methods. Metal injection molding produces large and small runs, complex shapes, and is ideal for all materials. The process developed from traditional powder metallurgy. It involves compacting lubricated powder mixed in rigid die through uniaxial pressure before ejection from the die for sintering.
Some of the advantages of this process include:
- Production of intricate parts
- Relatively cheap process
- Appropriate for all materials
Graphite mold casting
Also known as permanent mold casting, this process is similar to sand casting and die casting. This process involves pouring molten metal into a mold clamped shut for the material to cool and become solid into your desired shape. An expendable mold is utilized during sand casting which is destroyed after every cycle. Alternatively, permanent mold casting works like die casting. It relies on a metal mold or die made from cast iron or steel reusable for various cycles.
Since molten metal is just poured into the die but not injected forcibly, permanent casting is sometimes known as gravity die casting. This method is ideal for mass production of tiny metal components with uniform thickness. The process uses non-ferrous metal alloys including aluminum, copper, and magnesium.
Some of the common products manufactured through this process include pipe fittings, gears, and their housings, automotive components, and aircraft components like impellers, pistons, and wheels. Some advantages of this manufacturing method include:
- Low porosity
- Formation of complex shapes
- Exceptional mechanical properties
- Scrap is recycled
- Affordable labor cost
- Various material option
Before selecting a manufacturing plant, you have to understand the casting methods involved. This is very important to ensure that you understand what to expect after the process. Investment casting is a wonderful manufacturing process that produces various components with high precision and quality surface finish. Additionally, this manufacturing method eliminated post-machining making it cost-effective and time-saving.
