Aluminum CNC machining is a popular manufacturing technique in modern metal parts manufacturing industries.
For a successful CNC machining aluminum, you must choose the best material grade, know the benefits, choose a suitable technique, estimate the cost or apply the right surface finish.
So, if you want to be an expert in CNC machining aluminum, read this guide.
Aluminum CNC Machining Grades
Different aluminum grades find use across industrial applications with core differences detailed in inherent properties. They include:
| Aluminum Alloy | Machining | Workability | Corrosion resistance | Max. Operating Temperature | Hardness | Elongation | Strength (UTS) | Application |
| 1100 | Good | Excellent | Excellent | 218 °C | 25-28 HRB | 15 – 28% | 89.6 MPa | Dials, Heat Exchanger Fins, Nameplates |
| 2011 | Excellent | Poor | Poor | 138 °C | 95 HRB | 12 – 15 % | 275 MPa | Gears, Screw Machines, Tube and Pipe Fittings |
| 2024 | Fair | Poor | Poor | 200 °C | 70 – 120 HRB | 14 – 20% | 200 – 540 MPa | Aircraft fuselage, Vehicle Parts, Wing Tension Components |
| 6061 | Good | Good | Excellent | 130 – 150 °C | 60 HRB | 12 – 17 % | 291 – 320 MPa | Heat Exchangers, Marine Components, Aircraft And |
| 6063 | Fair | Good | Good | 260 – 510°C | 51.2 HRB | 18 – 33% | 145 – 186 MPa | Window and Door Frames, Railings, Roofs |
| 6082 | Good | Good | Excellent | 130 – 150 °C | 35– 56 HRB | 6.3 – 18% | 140 – 340 MPa | Construction: Bridges, Towers, Trusses |
| 7075 | Fair | Average | Poor | 100 °C | 79– 86 HRB | 2 – 11 % | 434 – 580 MPa | Missile Components, Aircraft Parts |
| 5083 | Fair | Good | Excellent | 80 – 100 °C | 74 HRB | 13 % | 270 – 350 MPa | Pressure Vessels, Marine Equipment |
| MIC 6 | Excellent | High | Excellent | 427 °C | 65 HRB | 3% | 166 MPa | Electronics, Machining Components, Laser parts |
More Resources:
Aluminum Alloy – Source: Wikipedia
Types of Aluminum Grades – Source: Metal Super Market
Types of Aluminum – Source: Thomas Net
Aluminum CNC Machining Advantage
Many benefits accrue from undertaking aluminum CNC machined parts in your project.
i. Corrosion Resistance: The resistance levels of the aluminum CNC machined grades differ depending on constituent elements. Nonetheless, it remains a standard feature allowing application of CNC machined parts in corrosive or exposed environments.
ii. Machinability: Aluminum is highly machinable and workable stemming from its ductility and malleability. This makes production economical since it is highly accurate and repeatable with reduced tool stress.
iii. Electrical Conductivity: While lower than copper conductivity, aluminum still exhibits acceptable electrical signal transfer. Thus, you can employ such CNC machine parts in applications where conductivity is necessary.
iv. Anodization Potential: After CNC machining aluminum parts, you can enhance its physical properties by anodizing. Anodizing enhances surface qualities of the CNC machined aluminum part such as thickness and wear resistance.
v. Recyclability: Unused or waste aluminum parts resulting from the CNC machining process can be recycled and worked on again. Recycling reduces pollution, waste of energy and even production cost needs.
vi. Strength-to-Weight Ratio: The high strength-to-weight ratio of aluminum allows for CNC machining of parts where strength and weight are of concern.
More Resources:
What is CNC Machining – Source: Thomas Net
CNC Machining Process – Source: Goodwin University
Limitations of CNC Machining Aluminum
You can encounter some difficulties when CNC machining aluminum. Some common setbacks include:
i. Workability: The different grades of aluminum and its alloys present a challenge during CNC machining affecting processes like milling and cutting
ii. Operating Temperature: The softness of aluminum and its low melting point limits the operating temperature when CNC machining. Consequently, undertaking CNC machining operations that result in high heat production can result in deformities.
Benefits CNC Aluminum Prototype Machining
Prototyping is a process that allows you to experiment or test a design before undertaking a complete production run. Its importance is highlighted as follows:
- Aluminum is readily available, easy to work with and recyclable thus incurs enormous cost savings.
- When undertaking CNC machining of aluminum prototypes, you can easily verify and implement designs without incurring huge losses.
Aluminum CNC Machining Processes
When it comes to CNC machining aluminum, there are many technologies you can adopt depending on your part specifications. For example, you may want to drill holes, make threads, or machine cylindrical parts.
As a result you must choose a suitable CNC machining technique:
CNC Turning Aluminum
When CNC turning aluminum, the cutting tool remains in position while you rotate the workpiece to remove unwanted material. The CNC turning lathe finds use in CNC turning aluminum utilizing computer-fed instructions to convert the aluminum workpiece into desired shape.
You can consider these CNC equipment to machine aluminum.
i. Vertical CNC Lathe
Here, the spindle is vertically fixed undertaking the turning operation by moving the workpiece up and down. It is favorable for one sided operations and where hanging of the workpiece is an issue.
ii. Horizontal CNC Lathes
Instead of a spindle like in their vertical compatriots, these CNC lathes horizontally implement multiple heads. Can undertake aluminum CNC machining in various designs with waste material easily falling off via gravity.
Advantages of Aluminum CNC Turning
Employing CNC turning in aluminum CNC machining affords you the following advantages:
- Cost Effective: CNC turning aluminum increases production efficiency by undertaking the process at shorter times thus making it cost-effective.
- Efficiency: CNC tuning of aluminium reduces wastage by making highly precise operations enhancing process efficiency.
CNC Milling Aluminum
CNC milling aluminum alloy is a popular operation today. You will use multi-point tool to process stationary aluminum material.
When it comes to CNC milling, you can use:
- Vertical CNC milling machine
- Horizontal CNC milling machine
- Multi-axis CNC milling machine
Multi-axis milling machines are capable of movement in multiple axis allowing faster and precise operations on aluminum workpieces.
CNC Milling Methods
There are several approaches to CNC milling aluminum workpieces as follows:
- Angular Milling: Here, the CNC milling machine tool’s axis of rotation and aluminum workpiece surface are separated at angle. Thus, produces specific designs such as grooves and other angled cuts.
- Face milling: Tool works downwards against the aluminum workpiece producing complex designs with the axis of rotation perpendicular to the workpiece.
- Form Milling: CNC machining aluminum with this milling method allows formation of rounded cuts by employing multiple tools.
- Profile Milling: Employs a three step process of roughing, semi and final finishing in producing concave and convex aluminum parts.
- Surface Milling: Removes material from the aluminum workpiece’s surface with the workpiece parallel to axis of rotation.
CNC Drilling Aluminum
CNC drilling aluminum workpieces involves employing special tools known as drill bits to create holes. These holes are essential during assembly especially when employing bolts, screws and rivets.
CNC Drill Types
The following CNC drill types can effectively transform aluminum workpieces for your application:
i. Gang Drill: Supports multiple work heads capable of holding several spindles and can undertake numerous operations simultaneously.
ii. Micro Drill Press: Has high accuracy featuring small chucks useful in making very small holes on stainless steel pieces.
iii. Multiple Spindle Drill: Features a single work head with multiple spindles with simultaneous work capability.
iv. Radial Arm Drill Press: Employs a wheel head capable of different movements to undertake several operations on a secured workpiece.
v. Turret Type Drill: Features a turret with multiple work heads allowing you to alter positions easily and quickly change the tooling.
vi. Upright Drill Press: This CNC drill type feeds the workpiece to a tool and features a spindle head with a gear drive.
CNC Cutting Aluminum
CNC cutting aluminum entails extracting appropriately sized aluminum pieces from larger sheets or bars according to design needs. Some of the CNC aluminum cutting equipment you can employ include:
i. CNC Laser Machines: Employs a computer controlled laser beam of high power to cut through aluminum. The cutting process is via vaporization, melting or burning resulting in highly precise cuts.
ii. CNC Plasma Cutters: These work by creating a powerful plasma arc from subjecting compressed air to extreme heating. The resulting plasma arc melts the aluminum while simultaneously blowing the melt away, cutting through it under computer control.
iii. CNC Router: Utilizes an endmill cutting tool bit to extract material or shape aluminum workpieces in the desired form. You also find it useful in separating larger aluminum pieces bearing in mind the bit type and rate of feed.
iv. CNC Water Cutters: Involves production of water jets mixed with abrasives under high pressure through tiny nozzles. The action of the jet striking the aluminum surface at high speed initiates cold cuts without deformation.
5 Tips for Cutting Aluminum with CNC Router
The CNC router can aid you in your projects by easily cutting aluminum to desired shape and size. However, you need to consider the following tips for correct cutting:
- Determine speed rate and feed for your CNC router usually by using a calculator to ensure a clean cut.
- When using a CNC router on aluminum, high RPMs are necessary necessitating the use of carbide cutters.
- Include a misting system in your setup to act as lubricant for the cutter and aluminum preventing wear and deformation respectively.
- Utilize progressive shallow passes in achieving the cut depth to ensure easy chip removal and quality end results.
- CNC cutting aluminum with a CNC router works with at most three flutes to prevent chip accumulation and thus jamming. Also, using reduced flutes goes hand in hand with a reduction in the feed rate.
Factors Influencing Tool Selection in Aluminum CNC Machining
Tool selection in aluminum CNC machining is essential in determining the cut quality and success of the process. Consequently tool selection is an important process that considers the following factors:
Cutting Fluid
While aluminum is soft, dry cutting results in burr formation and inconsistent edges making use of cutting fluids necessary. Oil emulsions are appropriate cutting fluids as those with traces of chlorine and sulphur leave stains on the aluminum surface.
Feeds and Speeds
The cutting speed when CNC machining aluminum refers to the rotations per minute of the tool. The tool parameters of radius and material influence speed.
You can employ high cutting speeds on aluminum to reduce chip build up and heat accumulation, and augment finishing quality.
Feed rate describes the travel by the tool in making a complete cycle. It also applies to workpiece’s where it is turned and the tool is held in position.
Tool Design
The tool configuration, say flute count, is vital in making or breaking an aluminum CNC machining process. For instance, having a low flute count (2-3) when working on aluminum ensures there is no chip build up.
Tool Material
Aluminum is a soft metal and machining tools require sharp edges not prone to wear such as carbide.
Alternatively, there are tooling systems made from cobalt. However, this is for situations where there is no reactivity with aluminum.
Reactivity with aluminum can cause surface infringements especially at high temperature.
However, you can employ carbide with slight cobalt content to achieve desired toughness without deformation.
Angle of Helix
It is the angle formed by the imaginary line cutting through the center of the tool and tangential plane of action. A large angle will make chip removal faster.
Of course, this will be at a cost of increasing friction. As a result, there will be a rise in temperature.
The resulting heat can result in the chips adhering to the tool by welding especially when machining at high speeds. Having an angle of helix that is small achieves the exact opposite.
Tips When CNC Machining Aluminum
The role of aluminum CNC machining is central to the production of many day to day appliances and equipment. Adhering to the following tips when CNC machining aluminum ensures quality products while also keeping you safe.
- Always apply lubricant. Lubricating your action area between tool and aluminum material reduces friction making the CNC machining process easier. It also ensures the edges are straight and prevents heat damage.
- Always remove formed chips. Allowing chippings to accumulate around your tool can result in breakage and aluminum deformation.
- Do not hasten the process. Employ the appropriate feed rate and speed depending on the tool, aluminum grade and machining process. You shouldn’t also employ very slow fed rates as it would only blunt the tool.
- Go with cutters with small diameters. This is especially true when trying to achieve a deep cutting depth as it makes the process smoother.
- Use the appropriate tool. For instance, when working on aluminum, carbide tools are preferable compared to HSS and cobalt.
How to Estimate Cost of Aluminum CNC Machining
Like all other projects, when aluminum CNC machining, you need to make a cost estimate. Having a cost estimate ensures you can budget for your needs and meet project demands.
When estimating the cost of aluminum CNC machining, you consider the following factors:
Material Needs
Essential considerations with regard to your material needs are the aluminum grade and size or quantity required. Since CNC machining aluminum involves subtractive processes, the design complexity will influence material usage.
Labor Needs
While many aluminum CNC machining equipment are computer controlled, they still require human supervision. Your labor needs are determined by considering the number of personnel, skill level, hours worked and compensation formula.
Surface Finishes for CNC Machines Aluminum Parts
Applying a surface finish to your aluminum CNC machined parts can enhance its physical properties and durability. Different surface finishes are applicable with some discussed below.
- Anodizing: Anodizing can result in a clear, colored or hard coat through electrical passivation improving corrosion and wear resistance.
- Bead Blasting: Results in a consistently smooth CNC machined aluminum part surface by eliminating tool marks and other surface deformities.
- Chromate Conversion Coating: Adding this coating over your CNC machined aluminum part maintains conductivity and enhances resistance to wear and corrosion.
- Decorative Chrome Plating: Chrome plating mainly serves aesthetic value on your CNC machined aluminum part while also enhancing surface durability.
- Polishing: Employs either mechanical or chemical means resulting in your aluminum part achieving a smooth and highly reflective surface.
- Powder Coating: Here, you apply paint powder on your CNC machined aluminum parts before subjecting it to oven baking. Powder coating enhances surface resistance and durability.
You can learn more about aluminum surface treatments.
Applications of CNC Machined Aluminium Parts
The application of aluminum CNC machined parts extends across industries finding use in almost every sector. Some common industry applications are as follows:
i. Automotive: The main properties allowing use of aluminum parts in the automotive sector are strength, light weight and durability.
ii. Food/Pharmaceutical: CNC machined aluminum parts find use, especially packaging, in food and pharma due to its phlegmatic nature when in contact with substances.
iii. Aerospace: The incredible strength relative to weight exhibited by CNC machined aluminum part makes their use in aircrafts highly popular.
iv. Sports: Many sports equipment and accessories employ aluminum CNC machined parts thanks to their durability, strength and weight. These include bicycle frames, baseball bats, racquets and whistles to mention a few.
v. Electrical: Since aluminum exhibits electrical conductivity in addition to its outstanding corrosion resistance, it features in many electrical components and appliances.
Conclusion
The versatility of aluminum and ease of CNC machining allows its wide usage in parts and component production. Aluminum CNC machining allows you to easily bring your project designs into life.
More Resources:
CNC Milling Components – Source: HMAKING
CNC Machining Aluminum Parts – Source: Protolabs
CNC Turning Parts – Source: HMAKING
CNC Machining Aluminum – Source: 3Ds
CNC Drilling Parts – Source: HMAKING
Benefits of CNC Machining Aluminum – Source: 3ERP
CNC Machining of Aluminum – Source: Xomerty
Aluminum for CNC Machining – Source: GENSUN