Burrs in aluminum alloy machines not only affect the visual of the machined parts but also hampers its fittings, leading to function failure. For deburring or fixing the burrs, you need to go through additional steps, which makes the process complex and also increases manufacturing costs.
To save you from these hassles, we bought you guidelines for tool and parameter optimization for reducing burrs in aluminum alloy machining:
What Are Burrs in Aluminum Alloy Machining?
Burrs are the unwanted rough edges formed while machining high ductile metal parts like aluminum alloy. This can occur during machining processes like milling, drilling, turning, or grinding.
Besides material property, burrs are caused due to several reasons like- tool defects, inaccurate cutting speed, etc. Such burrs not only affect the visual of the machined parts but also impact the fittings and performance of the machining part.
Burrs Hazards While CNC Machining Aluminum Alloy
Reduced Accuracy
Burrs hampers the actual shaping and dimension of the machined aluminum alloy part. Besides, it also affects the installation and fitting accuracy.
Part Damage and Shortened Lifespan
Repeated cutting forces and friction makes the burrs even harder. This can cause a crack in the machine’s part while removing it. Thus burrs damage your parts which lead to premature failure.
Injury Risks
While working with the burred machined part, the operator or users poses injury risk with the rough and sharp edges of the burrs.
Electrical Shorts
If burrs remain on contact surfaces, they can prevent proper electrical connections. This leads to voltage drops, overheating, or electrical failure.
Faster Wear and Machine Failure
The burrs created on the edges of the machine parts go through continuous collision which accelerates the wear and tear. This leads to faster wear out and machine failure risks.
Why Do Burrs Form in Aluminum Alloy Machining? Causes
Ductility of Aluminum
By nature, aluminum is soft and highly ductile, leading to easy plastic deformation under stress. This physical property of aluminum causes burrs formation during the machining of aluminum alloy metal parts.
Tool Wear or Incorrect Tool Geometry
Wear-out tools or improper tool geometry hampers the clean cut of the aluminum alloy. If the cutting tool is not sharp enough, it can bend or tear the aluminum, causing burrs.
High Cutting Speed & Feed Rate
High cutting speed puts excessive pressure on the machined part and tears up the metal causing burrs. Besides, when the feed rate is high, it generates excessive heat causing more aluminum deformation. As a result, the clean cut of the machined part is hindered, resulting burrs.
Poor Chip Evacuation
Inappropriate chip removal requires re-cutting of the chips, which leads to additional burrs. Besides, if you fail to evacuate the chips at high feed rates, they rub against the cutting zone, creating secondary burrs.
Types Of Burrs In Aluminum Alloy Machining
Poisson Burr
Poisson burrs appear along the edges of the working metal. It occurs due to the lateral expansion of the workpiece as it gets compressed while cutting.
Rollover Burr
While moving the cutting tools at the exit of the soft material like aluminum alloy, the edges get bent rather than a clean cut. This forms burr folds along the cut edges, which is challenging to remove.
Tear Burr
Tear burrs are created when you use a worn-out or unsharp tool for cutting, which tears the materials instead of a clean cut. This leaves a rough/sharp or jagged burr on the machined part.
Breakoff Burrs/Cut-off Burrs
Breakoff burrs or cut-off burrs are the unclean or rough edges formed when a part is cut from the stock material for machining. This happens because the material doesn’t shear off cleanly, leaving burrs.
How to Reduce Burrs in Aluminum Machining?
Use Sharp Cutting Tools
The toughness and ductility of aluminum alloy require sharp tools to bring clean cuts and reduce burr formation. For this, the selection of tools is crucial for machining aluminum alloy. The best tool materials for aluminum machining are as follows:
- High-speed steel (HSS) tools
- Carbide tools and
- Polycrystalline diamond (PCD) tools
Using the same cutting tool for a long time wears it out and affects its sharpness. If possible, sharpen the edges or replace it with a new one. However, go for PCD tools for longevity as they have high wear resistance.
For a refined cutting process, it’s best to choose composite tools like compound milling cutters or composite drills. Besides improving the machining quality, these tools help remove burrs formed by previous tools. This way, the chances of creating burrs in the next machining steps reduces.
Tool Path Optimization
Burrs mostly form when cutting tools exist in the workpiece. These burrs are larger than that of the burrs formed when the tool enters the workpiece. The direction of passing the tools plays a crucial role in forming burrs. For instance, using a traditional zigzag path for milling aluminum alloy forms larger burrs.
You can minimize the burrs by optimizing the tool pathway. Instead of a zigzag path, go for climb milling or contour milling.
Climb Milling:
In climb milling, the cutting tool moves in the same direction as the feed. This pulls the workpiece resulting in a cleaner finish and fewer burrs.
Contour Milling:
In contour milling, the tool moves smoothly around the edges without lifting or re-entering of the tool. As the tools remins in conact with the material throughout the process, it brings clean cut reducing burrs formation.
Optimize Tool Geometry
The angle at which you cut the aluminum alloy affects its burrs formation. Here, you must consider the rake angle, relief angle, nose radius, and chamfering. By adjusting these factors you can reduce the burrs on aluminum alloy.
| Tool Geometry Factor | What It Is | Recommended Range | How It Helps Reduce Burrs? |
|---|---|---|---|
| Rake Angle | The angle between the tool face and a line perpendicular to the workpiece surface. | Positive rake: 10° to 30° (higher for very soft aluminum alloys) | – Reduces cutting forces – Prevents work hardening – Minimizes heat buildup |
| Relief Angle | The angle between the tool’s flank face and the machined surface. | 5° to 15° (Depends on feed rate) | – Prevents tool rubbing – Reduces friction – Minimizes material tearing |
| Nose Radius | The radius of the cutting edge at the tool tip. | 0.2 mm to 1.6 mm | – Strengthens edge – Controls chip flow – Reduces deformation |
| Chamfering | A small, angled edge on the tool’s cutting edge. | Width: 0.05 mm to 0.2 mm Angle: 5° to 20° | – Strengthens cutting edge – Improves chip evacuation – Prevents exit burrs |
Adjusting Cutting Speed
Higher cutting speed improves material removal rates but may increase tool wear and heat generation leading to burrs formation. This is why maintaining optimal cutting speed is essential. However, the cutting speed varies for different aluminum alloys.
Feed Rate (IPR – Inches Per Revolution)
The feed rate determines how quickly the tool removes material from the workpiece. A faster feed rate, though, aids in quick material removal; it usually leaves burrs. In contrast, a slower feed rate provides smooth cutting with minimal burrs formation. The feed rate ranges for roughing and finishing cuts for aluminum alloys are as follows.
| Cut Type | Roughing Cut | Finishing Cut |
|---|---|---|
| Feed Rate | 0.005 – 0.020 IPR | 0.002 – 0.004 IPR |
Depth of Cut (DOC)
The DOC refers to how deep the tool penetrates the material during each pass. It is measured in inches or millimeters. A larger depth of cut passes deeper into the workpiece, but they wear out the tools faster, increasing the burr formation. However, DOC and feed rate are interrelated.
- Larger DOC = Slower Feed Rate
- Smaller DOC = Faster Feed Rate
NB: The relation is not a hard set rule; it can change based on the material property, tool geometry, etc.
Below we are adding DOC correspondence to the feed rate for lathe machining aluminum alloy:
| Cut Type | Depth of Cut | Feed Rate (IPM) |
|---|---|---|
| Lathe Finishing Cut | 0.01 in. to 0.03 in. | 0.005 – 0.020 IPM |
| Lathe Finishing Cut | 0.002 in. to 0.012 in. | 0.002 – 0.004 IPM |
Choose the Right Cutting Fluid: Coolant and Lubrication
Coolant and lubrication prevent the overheating of the tools while machining. This also smoothens the cutting to give an even finish removing burrs. The common lubricants used for aluminum alloys are as follows:
- Maxisol Al
- Trim SC520
- Hai Lu Jya He’s Cutting Fluids (specifically formulated for aluminum)
- Petroleum-based oils (e.g., mineral oil)
- Soluble Oils (e.g., emulsions)
Quality Control and Inspection
Regular inspections of your machining help you to identify the potential risks of burrs and solve them before it creates major issues. Thus, adjusting the parameters like cutting speed, feed rate, depth of cut, and tool condition minimize burrs.
How to Remove Burrs from Aluminum Alloy? Deburring
Deburring Tools
For removing small burrs in aluminum alloy machining, you can use manual tools like deburring knives. Again for larger or more intricate parts, rotary tools work great to fix burrs. However, you must go with consistent pressure and have a steady hand for the best result.
Chemical Deburring
Chemical deburring is applicable for hard-to-reach areas where your tools can’t reach. These chemicals dissolve burrs from aluminum parts giving the machined part a finished look. The most suitable chemicals for aluminum alloy deburring are as follows:
- Phosphoric Acid Solution
- Acetic Acid (Acetum)
- Nitric Acid (Salpeter Solution)
- Copper Nitrate
- Aluminum Chemical Deburring and Polishing Agent Q/Ys. 204-2
- Al-chem 300 Process
- M-111 Non-Ferrous Deburring Compound
- M-222 Non-Ferrous Deburring Compound
However, you must maintain safety protocol and handle the chemicals carefully while deburring.
Abrasive Methods
Abrasive methods are a quick solution to remove burrs and smoothen the ages of aluminum alloy machined parts. Nevertheless, you should choose the aversive methods wisely to ensure it doesn’t damage the aluminum. The common aversive methods are as follows:
| Abrasive Method | Description | Effective For |
|---|---|---|
| Sanding | Uses abrasive paper or pads to smooth out edges | Small burrs or edges |
| Grinding | Uses a rotating abrasive wheel to wear down burrs | Medium burrs |
| Abrasive Blasting | Uses compressed air to propel abrasive materials (e.g., sand, beads) at the part. | Fast and effective for large volumes |
Conclusion
Burr formation can be caused due to wear-out tools, inappropriate cutting speed, feed rate, the vibration of the machine, etc. Therefore, before machining the aluminum alloy, optimization of tools and the machine parameters is necessary. Besides, use of lubricants is also helpful to reduce burrs.
However, stay tension-free with RICHCONN aluminum alloy CNC machining services. Our machine parts are applicable for aerospace, automobile, medical devices, and more. Besides, no worries with burrs as we are certified and maintain tight tolerance levels. So, without any further delay, contact us ASAP to place your order!
FAQs
What is the best way to deburr aluminum?
The best way of deburring aluminum varies for specific applications. For small to medium burrs, manual deburring tools or rotary deburring tools work best. Again, for tighter spaces or complex areas, chemical deburring is the ultimate option. If you are deburring for larger burrs, sanding or grinding are highly effective options. And for high-volume production, go for abrasive blasting.
Why is it important to remove burrs in aluminum alloy?
Burrs hampers the original shape of the machined aluminum alloy that affects the r fit or function of components during assembling. This poses a risk of sudden function failure, detachment, or jamming of parts. Moreover, the sharp edges form the burrs and cause cuts or injuries during handling and assembly.
Why should I use coolant when machining aluminum?
Aluminum generates heat during the cutting procedure, which leads to tool wear and material distortion. Using coolant prevents the overheating of the aluminum and lubricates it to bring a smoother cut. Additionally, it helps flush away chips and swarf from the cutting zone.
Can you remove burrs with a CNC machine?
Yes, using CNC machines, you can remove burrs, as many of them are equipped with deburring attachments, or you program them for specific deburring operations. This deburring process is ideal for large batches to ensure consistent burr removal.
