Delamination after aluminum‑sheet cutting is typically not caused by a single factor, but rather by the combined effects of the material, tooling, equipment, and process parameters. Below, we will provide a systematic troubleshooting and resolution guide, covering both root cause analysis and proposed solutions.
Cause Analysis
Delamination in aluminum sheets primarily occurs in laminated or composite aluminum panels (such as aluminum‑plastic composites); however, even solid‑aluminum sheets can exhibit a tearing pattern resembling “delamination” during cutting if they contain internal impurities, have coarse grains, or suffer from uneven residual stresses. The main reasons can be categorized as follows:
1. Issues with the material itself:
- Low-quality composite panels: Poor‑quality adhesives between the core material and the aluminum cladding, coupled with inadequate bonding processes, are the primary causes of delamination during cutting.
- Internal stresses in the material: Residual stresses generated during rolling or heat treatment are relieved upon cutting, leading to non-uniform deformation and delamination.
- Material is too soft or coarse grain: pure aluminum or soft aluminum (such as 1100-O) is more likely to be “torn” rather than “cut” when cutting “.
2. Cutting tool problem:
- Tool passivation: This is one of the most common causes. The passivated tool cannot cut the material sharply, but separates the material by “squeezing” and “tearing”. The huge lateral force will “pry” the aluminum skin from the core material.
- Tool angle is not suitable: the front angle, rear angle and other geometric angles are not suitable for aluminum cutting, which will lead to excessive cutting force and poor chip removal.
- Wrong tool type: A tool designed for steel or other materials was used.
3. Cutting process parameters:
Incorrect feed speed:
- Too slow: The tool will rub on the material instead of cutting, generating a lot of heat, softening the adhesive, and aggravating the work hardening.
- Too fast: The impact force is too large, exceeding the bonding strength of the adhesive, and the material is directly “punched.
Incorrect speed:
- Too low: cutting force, easy to cause tearing.
- Too high: may affect the cutting quality due to vibration or poor chip removal.
- Cutting depth is too high: once cut too deep, cutting resistance increases sharply, easily lead to delamination.
4. Equipment and auxiliary system problems:
- Insufficient rigidity of the equipment/large vibration: The vibration of the machine tool, spindle or tool holder will be transmitted to the cutting point, forming a periodic impact force, which can easily lead to stratification.
- Insufficient cooling/lubrication: Especially for composite aluminum plates, the high temperature generated by cutting will melt the plastic core material in the middle or cause the adhesive to fail.
Systematic Solutions
Please follow the steps below to check and adjust one by one to find the most suitable solution for your current situation.
Step 1: Check and optimize the tool
This is the most direct and effective step.
1. Make sure the tool is sharp: immediately replace or regrind the passivated tool. For aluminum cutting, keeping the knife sharp is the most important thing to ensure the quality of cutting.
2. Select the appropriate tool type:
- It is recommended to use special tools for aluminum: these tools usually have larger chip grooves, sharper rake angles and specially treated coatings (such as Polymand coatings) to reduce aluminum chip adhesion.
- Tooth profile design: For laminates, it is recommended to use a tool with multiple teeth (high teeth), which can ensure that the cutting amount of each tooth is smaller and the cutting force is more stable.
- Tool material: carbide (tungsten carbide) tool is the first choice, its hardness and sharpness can be well balanced.
3. Optimize the tool geometry parameters:
- The use of large front angle (such as 10 °-20 °): sharp positive front angle can be like a planer to easily “cut” under the material, rather than “squeeze” open material, can significantly reduce the cutting force.
- Larger relief angle: reduce the friction between the tool flank and the machined surface.
Step 2: Adjust the cutting parameters
The parameters are optimized on the basis of good tool condition.
1. Follow the principle of “fast knife and slow walking” (for aluminum):
- High speed: within the scope of equipment capacity, use a higher spindle speed.
- Suitable feed speed: Calculate and set a feed speed that matches the speed. Do not be too slow, otherwise the friction heat is serious. The formula can be used: feed speed = rotation speed × number of teeth × feed per tooth. For aluminum, the feed per tooth (Fz) is usually between 0.01-0.1mm, and the laminate is recommended to take an intermediate or smaller value for testing.
2. Layered cutting:
- If the plate is thick or cut through the impact force is large, do not cut through. When programming, layered cutting is used, and each cutting depth is controlled at about 0.5-1 times of the tool diameter, and gradually cut through. This can significantly reduce the single cutting force.
Step 3: Improve the auxiliary conditions
1. Strengthen cooling and lubrication:
- Cutting fluid must be used: good cooling can take away heat and prevent adhesive failure and aluminum chips from sticking to the knife. Lubrication can reduce cutting forces.
- Change the cooling method: If possible, use spray cooling (MQL) or high-pressure internal cooling, which can directly affect the cutting point and help chip removal.
2. Reduce vibration:
- Check the stability of the machine tool and fixture to ensure that the workpiece is clamped firmly.
- Use the shortest possible tool to increase rigidity.
- If you use light equipment such as engraving machines, you can consider reducing the speed and feed appropriately to sacrifice efficiency in exchange for quality.
Step 4: Control from the material source
If the problem persists after all the above methods have been tried, it is likely that the problem is with the material itself.
1. Communicate with the supplier: report the delamination problem to the aluminum plate supplier and ask whether the batch of materials has similar feedback from other customers.
2. Replace the material brand or batch: try to use other brands or higher quality aluminum plates, especially choose a reputable composite board brand.
3. For simple aluminum plate: choose the plate with better quality and more uniform internal organization.
Summary and Quick Checklist
When you encounter a tiering problem, check in this order:
1. [Primary Inspection] Replace a brand new, sharp aluminum special milling cutter/saw blade.
2. [Adjust parameters] Increase the speed and match a “just right” feed rate-not too slow or too fast. Try cutting in layers.
3. [Enhanced cooling] Ensure that the cutting fluid is accurately poured in the cutting area.
4. [Inspection Equipment] Clamp the workpiece, shorten the overhang of the tool, and reduce vibration.
5. [Final Means] If they are invalid, if the material problem is suspected, replace a batch or brand of aluminum plate for testing.
Through this systematic investigation, the vast majority of aluminum plate cutting delamination problems can be effectively solved.