Introduction to Casted Materials in CNC Machining(cnc code Janice)

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CNC (computer numerical control) machining is a manufacturing process that uses computer-controlled tools to shape stock material into custom parts and products. One of the key advantages of CNC machining is its compatibility with a wide range of materials, including casted materials. Casted materials refer to metal alloys that have been heated until molten and poured into molds to produce casted stock shapes. Common casted materials used in CNC machining include aluminum, brass, bronze, cast iron, and steel.
Casted parts have unique properties that make them well-suited for certain CNC machining applications. This article will provide an overview of casted materials in CNC machining, including:
- Benefits of using casted materials in CNC machining
- Common casted material options for CNC
- Considerations when machining casted materials
- Secondary processing of casted CNC machined parts
- Example applications utilizing casted materials
Benefits of Casted Materials for CNC Machining
There are several key advantages to using casted stock material in CNC machining processes:
- Cost-effectiveness: Casting provides a cost-efficient way to produce metal stock shapes and blanks for machining. The upfront investment in a mold or pattern is offset by lower per-part costs.
- Complex shapes: Intricate, complex geometries can be casted before machining, reducing cycle times and tool wear.
- Material properties: The rapid cooling of molten metal during casting creates unique grain structures and properties. These can enhance strength, hardness, or other attributes.
- Wide availability: Many aluminum, iron, steel, brass, and bronze alloys are available readily casted into bar, rod, and other stock.
By beginning the manufacturing process with casted blanks, CNC setup time and machining difficulty can be greatly reduced.
Common Casted Material Options for CNC
The most common casted materials used for CNC machining include:
- Aluminum alloys: Cast aluminum is highly machinable. 6061, A356, 319, and 380 are frequently used grades.
- Brass: Cast brass alloys like C360 or C35000 provide excellent machinability and corrosion resistance.
- Bronze: Tin bronzes such as C90300 and leaded bronzes like C93200 offer superior wear resistance.
- Cast iron: Grey cast iron alloys provide vibration dampening. Nodular or ductile cast iron offers greater strength.
- Steel: Low carbon steel allows for easy machining. High carbon and alloyed cast steels provide increased wear resistance.
The specific alloy can be selected based on required mechanical properties, corrosion resistance, weldability, and cost.
Considerations for Machining Casted Materials
While casted metals provide benefits, there are some unique challenges when machining casted stock:
- Porosity: Castings can contain small voids or pores from cooling that must be accounted for during machining.
- Residual stress: The rapid cooling causes internal stresses in the material that may lead to distortion. Stress relieving heat treatment prior to machining can help.
- Variability: There is some inevitable variability part-to-part in casting process, which needs to be designed for.
- Hard spots: Certain cast alloys are prone to work hardening during solidification, creating local areas of hardness.
- Rough surfaces: The as-cast surfaces tend to be rougher than wrought or extruded stock. More finish passes may be required.
With proper feeds, speeds, tooling, and programming, quality machined parts can be produced from casted metals. But the unique properties require special consideration.
Secondary Processing of Casted CNC Parts
Complex casted CNC components often require additional secondary processing after the initial machining, including:
- Heat treatment: Stress relieving, annealing, hardening, and tempering heat cycles enhance final material properties.
- Plating/coating: Electroplated layers or sprayed metal coatings provide corrosion and wear resistance.
- Surface treatments: Anodizing, blasting, polishing, etching, and other finishes improve appearance and function.
- Secondary machining: Additional turning, milling, grinding, or drilling operations refine critical features.
- Quality control: Rigorous inspection, testing, and metrology verifies that all specifications are met.
- Assembly: Components may be partially assembled to other casted or wrought parts to become sub-assemblies.
With proper secondary processing, casted CNC machined parts can achieve the tolerances, surface finishes, and performance required for the application.
Example Applications Using Casted Materials
Some examples of products manufactured from casted metals on CNC machines include:
- Automotive parts - Engine blocks, cylinder heads, intake manifolds, and pump housings utilize casted aluminum, iron, and steel.
- Aerospace components - Cast turbine blades and impellers are machined from nickel and stainless steel alloys.
- Fluid system parts - Bronze and ductile iron valves and fittings resist wear and corrosion.
- Consumer products - Grill and oven housings, patio furniture, and sculpture utilize cast aluminum.
- Industrial machinery - Baseplates, guards, gears, and brackets employ cast iron, steel, and brass.
- Medical equipment - MRI and medical laser bases are machined from cast iron for vibration dampening.
In summary, casted materials provide an excellent starting point for cost-effective CNC machining of precise, reliable, and high-performance components across nearly every industry. With an understanding of the unique properties and proper processing techniques for casted stock, manufacturers can improve productivity, quality, and profitability through integrating casting and CNC machining operations. CNC Milling CNC Machining