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How Do You Make Aluminum Parts? 

What does the number 13 have to do with machining? For aluminum, 13 is the number placement on the Periodic Table of Elements. Being such a highly conductive and ductile alloy, Aluminum is one of the most machined materials today. Chosen often for its versatility in properties for strength and being lighter than many other metallic materials. First discovered back in 1825, it was not until about 1889 that the process was developed for industrial quantities and usage. Aluminum is abundant in the earth’s crust as a compound and not an ore. Through processing the three most widely used types are: MIC-6, 6061 and 7075. How are aluminum parts made with a CNC machine? Well, it’s not as easy as turning a machine on. There is science, skill and some artistry involved from years of experience by qualified service providers.  The following will be a basic guide to the steps in this process. 

  • Material selection: 
    • Projects requiring MIC-6, – This grade is softer but used in many applications requiring flatness and superior consistency in the flatness and no distortion. 
    • Projects requiring 6061-gnerally used as a “standard” grade. Used most often and is about the middle of hardness and has lower cost for raw material. Is easily welded. 
    • Projects requiring 7075 Most critical, with higher quality requirements and tighter tolerances. Not easily welded. This grade has hardness close to steel and has higher costs. 
  • Design files: CAD/CAM files are used. These program the machine and will determine the size of the part to be made. The selection of the materials and design determines the best CNC machine to use. 
  • Machine selection: CNC machines used for machining Aluminum. These would include CNC lathes and vertical milling.  
    • CNC- Can hold +/- .0254mm to .0508mm. Use rotating end mills to remove material from the work piece. 
    • Lathes-These will rotate the work piece while the cutting tools shape the design. 
    • Routers- These rotate the tools or bits at high speeds to perform the cutting. 
    • Other CNC- can hold +/- .127mm. 
  • Securing the work piece is critical by using clamps, vices, and other methods. 
  • Determining the “Speeds and Feeds” for each project:  
    • RPM- Revolutions per Minute- The speed that the tools bits are run. Affecting throughput, surface finish and tool life. 
    • Feed Rate- The speed that the tools move through the aluminum is listed in IPM or Inches per Minute. Affecting the quality of the cut edge, and the throughput. 
  • The type of tool bits used: 
    • Hardened Steel- Best used for shorter runs. 
    • Carbide bits- Best used for longer production runs, as the bits last longer. 
    • Coolant or cutting fluids are also used during the process and categorized as soluble oils, synthetic, semi-synthetic and straight oils. This keeps the aluminum cool and helps reduce the slag and aid in the cut edge quality.  
  • Debris and dust collection: CNC systems can collect debris formed during the process. These chips and bits can cause reduced performance if not managed.  
  • Deburring: Machining can create burs; these are removed basically by two processes: Manually with deburring knife or sanding. Internal deburr- Some machines have an internal mechanism to deburr. 
  • Quality control- Many machines do have internal quality systems that review the machined part. Other methods include a secondary inspection system. 
  • Pre-and Post Handling- Since Aluminum is softer compared to steel, the surface can be marred or damaged if not properly handled.  

What is the best Machine for Custom Aluminum Parts? 

Machining is a service and manufacturing business, producing countless parts for so many industries. The world as we know it would not be so without this technology. The process of taking a raw block, plates and sheets of materials and creating what the designers, the engineers had in mind to come into reality. With numerous material options available, one of the most frequently used is aluminum. Why aluminum? It has versatility as being strong, but lighter than other metallics. It is ductile and has good thermal qualities. Machining this alloy is done best using specific methods per project. 

  • Material selections: The three most used grades of aluminum are: MIC-6, 6061 and 7075. 
    • MIC-6- These cast plates of Aluminum are revered for the stability they have in producing consistency, high quality to parts in industries such as aerospace, electronics, marine usage, consumer electronics. Is softer than other grades. 
    • 6061- The workhorse of aluminum- Used most widely for many projects, it has a hardness greater than MIC-6 and is easily welded. 
    • 7075- Used in applications requiring strength but in a lighter weight than steel. 7075- is used in industries such as Defense, aerospace, automotive, mold and fixturing, for example. The hardness is comparable to steel. Not easy to weld. 
  • UV or Ultraviolet laser technology: Best for projects requiring ultra-thin foils. 
    • Thickness from .0254mm to .254mm thick. 
    • Great for 2D geometries. 
    • The kerf of these lasers can be 20um or smaller. 
    • Allows for finer geometry to be cut with a +/- .0254mm tolerance.  
    • No vibration to subjected to the material. 
    • No tooling so design changes made easy. 
  • Fiber Laser Technology: Best for thicker grades of aluminum.  
    • Thickness from .254mm up to 40mm or thicker. 
    • Great for 2D geometries. 
    • Higher power (wattage) but relatively small beam diameters of 18 to 40um.  
    • Clean edge cuts and tolerance of +/- .0508mm. 
    • Heat affected zones controlled by programing. 
  • CNC Machines can cut from flat plates and blocks of uncut Aluminum. 
    • CNC Machines include CNC lathes and CNC Vertical mills as well. 
    • They are controlled by computer generated design files. 
    • Great for flat and 5-axis parts. 
  • Tolerances held depend on the geometry and the type of CNC machine: 
    • For Vertical CNC- can be +/- .0254mm to .508mm. 
    • Other CNC systems can have tolerance of +/- .127mm. 
    • Coolant is used to reduce heat affect. 

The quality of the manufactured parts is controlled differently by each method mentioned. There is a balance of factors for each custom job ensuring the best throughput, quality of cut and surface finish. Having a conversation with your preferred provider before the manufacturing process is started will ensure the desired outcome is met.