Introduction to Casted Materials in CNC Machining(difference between hot rolled and cold rolled steel Eli)

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CNC (Computer Numerical Control) machining is a manufacturing process that uses computer-programmed machining tools to shape and cut raw material into finished parts and products. CNC machining is commonly used with metals, plastics, wood, foam, and wax blocks. However, casted materials are also frequently machined with CNC to achieve high precision and complex geometries.
What is a Casted Material?
A casted material refers to a material that has been formed by pouring molten metal, plastic, or other material into a mold and allowing it to solidify. The casting process allows for the production of complex shapes that would be difficult or impossible to create through other manufacturing methods. Once hardened, the casting is removed from the mold. Common casted materials used in CNC machining include aluminum, iron, steel, brass, bronze, plastic, and zinc.
Benefits of CNC Machining Casted Materials
There are several benefits to using CNC machining with casted materials:
- Complex shapes: Casting produces intricate, organic, or curved geometries that cannot easily be recreated through subtractive machining alone. CNC machining can then provide additional refinement.
- Lower machining time: Because casting produces a "near-net" shape, less material needs to be removed during machining. This reduces cycle times.
- Material options: Casted materials like metals and plastics can be machined in ways not possible with natural raw material blocks.
- Combining processes: Casted parts can also undergo secondary CNC processes like drilling, milling, and turning for additional features.
- Prototype creation: CNC machined castings allow prototypes and concept models to be produced without the need for custom molds.
- Small batches: Casting combined with CNC machining enables small production batches where injection molding would be too costly.
Preparing Casted Parts for CNC Machining
Proper preparation is crucial when CNC machining casted parts:
- Remove sprues/gates: Sprues and gates used in the casting process must be removed, often through manual cutting, sawing, or grinding.
- Heat treatment: Some casted materials like aluminum or steel will require heat treatment like annealing to increase machinability.
- Surface preparation: Cast surfaces should be evaluated for any irregularities and may need to be pre-machined or ground smooth.
- Fixturing: Appropriate fixtures and workholding devices should be used to securely hold the casting.
- Support structures: Features like thin walls or overhangs may require temporary support structures during the machining process.
CNC Machining Operations for Castings
Common CNC machining operations well-suited for casted parts include:
- Milling: Used for complex 3D shapes, pockets, contours, slots, and surface finishing.
- Turning: For cylindrical or rotationally symmetric castings, turning produces rounded geometries.
- Drilling: Adding precision holes for fasteners, bearings, bushings, and mounting.
- Boring: Enlarging or smoothing existing holes and cavities in the casting.
- Tapping: For threaded holes, tap casting while on the CNC machine for correct alignment.
- Broaching: Cutting internal keyways or splines within a casting via broaching tools.
- Knurling: Adds raised diamond or straight patterns for improved grip.
For best results, the appropriate tooling, speeds, feeds, and depths should be selected for the specific casted material being machined.
Example Applications
CNC machining is ideal for adding precision details and features to casted components across many industries:
- Automotive: Engine blocks, wheels, gearboxes, pumps
- Aerospace: Turbine blades, flight controls, engine parts
- Military/Defense: Weapon components, armour, vehicle parts
- Medical: Joint replacements like hips, knees, surgical instruments
- Marine: Propellers, steering gears, cargo components
- Construction: Boom sheaves, railings, equipment parts
- Material Handling: Forklift carriages, crane sheaves
In summary, combining the design freedom of casting with the accuracy of CNC machining opens new doors for producing complex, high-performance casted parts cost effectively. With the right planning and techniques, quality castings and CNC machining are natural partners in manufacturing. CNC Milling CNC Machining