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Metal CNC Machining
AT offers a diverse range of metals for CNC machining, with applications in a variety of industries. Ideal for one-off prototypes as well as end-use custom parts.
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CNC Machining Metal
Choosing the proper metal for CNC machining involves considering some factors. The metal you select is critical to the final success. For example, the metal may need to be resistant to high temperatures or bend or break under pressure. When choosing the correct metal, corrosion resistance, workability, pricing, weight, and visual look all play a role.
| Image | Name | Description | Price |
|---|---|---|---|
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Good machinability + High tensile strength + Good ductility and weldability |
$$$ | |
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Good machinability + Excellent thermal and electrical conductivity |
$$ | |
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Excellent strength to weight ratio + Corrosion resistant |
$$$$$ | |
Aluminum is one of the most cost-effective metal materials for metal CNC machining. Asides from its inexpensive nature, this metal also has an ideal strength-to-weight ratio and high performance, making it ideal for lightweight machining parts.
Besides, aluminum has high machinability, allowing the manufacture of parts cheaply and quickly. There are different grades of aluminum used in CNC machining. These include:
AL6061-T6 is the most widely used aluminum grade in CNC machining. It is an economical grade with excellent machinability, workability, and atmospheric resistance. On the downside, this grade of aluminum has low resistance to salt water and chemical.
The 6061-T6 grade is ideal for machining construction materials, aerospace components, and transportation equipment.
Al7075-T6 is a high-grade metal with excellent strength, making it an ideal choice for CNC machined parts in industries like automobiles and aerospace. Its ductility, toughness, and fatigue resistance make Al7075 suitable for manufacturing high-stress structural components.
This is the aluminum grade commonly used for machining. Of all the 6000 series, the 6082 has the highest strength, even stronger than the 6061.
Its strength is due to its large amount of manganese, which controls its grain structure. The 6082 has excellent corrosion resistance making it ideal for use in the aerospace and defense industry.
Stainless Steels
Although not as highly machinable as aluminum, stainless steel still has good machinability. It also has an affordable CNC machining cost, making it a good alternative for machining components or parts.
There are different grades of stainless steel material ideal for CNC machining, but the common ones include the following:
This is one of the most common stainless steel grades used for machining. It has good formability and weldability.
It has applications in milling a wide range of kitchen utensils and appliances. Also, SS304 has applications in manufacturing pipes and machinery for food handling.
The SS303 grade of stainless steel has excellent corrosion resistance and durability. These properties make SS303 ideal for the metal fabrication of gears, shafts, bushings, nuts and bolts, and aircraft fittings.
The 303 stainless steel grade contains 17% chromium, 8% nickel, and 0.15% sulfur. However, this sulfur content makes it impossible to harden this metal through heat treatment.
The SS316 grade of stainless steel has incredible corrosion resistance and strength. This corrosion resistance is due to its 2% to 3% molybdenum content asides from its chromium and nickel content.
The high strength of SS316 gives it specialized use in both aerospace and medical implants.
Copper
Copper has high thermal and electrical conductivity, making it ideal for making electrical products. Although copper is an expensive material, it has excellent machinability.
Brass is a metal alloy made from a combination of copper and zinc. Consequently, it has a high degree of machinability and tensile strength. It also has excellent thermal and electrical conductivity.
Brass also has a natural resistance to saltwater corrosion and retains its properties even at low temperatures. Being highly workable, this metal can achieve a high and aesthetically pleasing polish.
On the downside, however, brass has medium hardness and is quite expensive, raising the cost of machining. Brass is ideal for making electrical, plumbing systems, automotive, musical instruments, and medical products.
Titanium
Titanium is one metal that has an excellent strength-to-weight ratio, as well as temperature and chemical resistance. Its high strength and biocompatibility make it ideal for making medical devices. Other applications of this metal are in the aerospace and high-end automotive industry.
However, titanium raw material is costly, making it an expensive metal to machine.
Magnesium
The high thermal conductivity and the mechanical properties of magnesium make it one of the easiest materials for metal CNC machines. It is also a lightweight metal, about 35% lighter than aluminum, making it ideal for use in the automotive and aerospace industries.
However, there are risks to CNC milling magnesium, which include fire hazards as this material can burn underwater, nitrogen, and even CO2.
What Factors Should Be Considered When Choosing A Metal for CNC Machining?
Choosing the right material goes a long way to determining the cost and function of the final product. With the right material, it becomes possible to balance, use, cost, and machinability. Here are some factors to consider when choosing a material for CNC machining;
CNC Machining Time
The type of metal chosen often determines the time spent machining it. Selecting a metal with low machinability would extend the CNC machining time considerably, as opposed to selecting a metal like aluminum with its high precision machinability. Furthermore, the longer the time spent machining, the more expensive the manufacturing process becomes.
Another factor that determines machining time is the complexity of the parts. A CNC machine would spend more time machining a complex part than a simple part, which also increases CNC machining costs.
Strength and Environment Requirements for the CNC Machined Parts
The proposed use of CNC machined parts is another factor that would determine the choice of metal. For instance, when making parts that would experience heavy stress and loading, a metal with high strength, like steel alloy, is better than copper.
On the other hand, where the final product should have strength similar to steel but without its weight, like in the manufacturing of aircraft, then titanium might be ideal.
Additionally, the environment in which the part would operate is another factor that should determine the metal used for making the part.
Finishes and Post-Processing for CNC Machined Metals
The type of metal selected also determines the finishing and post-processing of the machined parts. For instance, soft metals or hard metals with low machinability often have tooling marks and burs, which finishing and post-processing help remove.
Although finishing and post-processing improve the appearance of a metal part, it also raises the cost of machining significantly.
However, knowing the finishing and post-processing required makes it easier to choose the right metal for part metal fabrication. In most cases, it will be a metal with high manufacturability if a high-quality surface finish is important.
What Types of CNC Machine AT-Machining Can Machine Metals?
Metal machining is a complex process left to professional machinists. AT-machining is one of the best precision metal fabrication companies globally that offers offline and online CNC machining services at affordable prices.
Below are the metal CNC machines we utilize for CNC machining.
CNC Lathe
This stationary cutting tool is ideal for shaping metal and plastic. It has the lowest cost per part relative to other CNC machining operations and very high production parts capabilities.
3 Axis CNC Milling
This CNC milling machines produce parts with excellent accuracy, at a low cost, and with relatively simple geometries.
Milling-Turning CNC Center
This machine utilize the advantages of both CNC milling and turning in a single system to produce complex parts more affordably than 5-axis machining. It offers a high degree of design freedom and manufacturing capabilities.
Indexed 5-Axis
This machine produces parts that do not align with one or the main axis with high accuracy. However, using it for machining is quite expensive.
Continuous 5-Axis
This is the most expensive machine we use for machining. However, it produces complex parts with high accuracy that require minimal machining mark.
Process Selection
| Process | Relative Cost | Benefits | Limitations |
|---|---|---|---|
|
CNC Turning (Lathes) |
85% |
Produce the parts at a lower cost compared to CNC Milling High production capabilities |
Can only produce cylindrically shaped parts |
|
CNC Milling (3-axis) |
100% |
Manufacturing parts with simple geometries quickly and precisely and at a low cost |
Manual repositioning of workpieces reduces the achievable accuracy |
|
Mill-turning CNC centers |
125% |
Lower cost than 5-axis CNC machinine. High production capabilities & design freedom. |
Tool access and workpiece clamping design restrictions apply |
|
Indexed 5 Axis (3+2 ) |
160% |
Eliminates the need for manual repositioning. Produce parts with features that do not line up with one of the main axes quicky and precisely |
Higher cost than 3-axis CNC milling |
|
Continuous 5 Axis |
200% |
Manufacture complex parts with an accuracy that cannot be achieved by any other process. Produces a very smooth "organic" surface with minimal machining marks. |
Highest cost of all CNC machining. |
Frequently Asked Questions
There is no fixed cost for metal CNC machining, but there are ways to reduce CNC machining costs. The cost depends on many factors, including metal fabricators and the attributes of your project, such as tighter tolerances and computer-aided design complexity.
Metal machining refers to the fabrication of metal parts or products by CNC metal machines. It is a controlled subtractive manufacturing process for cutting raw materials into a desired final size and shape. It involves milling machines, lathes, drill presses, and other CNC machines.
You can make various metal parts and products like bolts, nuts, and parts for the automotive, aerospace, and defense industries. With CNC machines, you can also make metal art through etching, engraving, or carving metals.