Problems that may occur during the production process of aluminum profiles and solutions to the problems encountered

Issues and Solutions Related to Extrusion Processes

1. Uneven wall thickness or too thin/too thick:

Reason: Too thin: The metal has poor fluidity and is difficult to fill the die holes, resulting in the profile breaking or deforming. Excessive thickness: It is prone to causing "shrinkage marks" (surface depressions), slow cooling, low production efficiency, and material waste. Unevenness: It leads to different cooling rates, generates severe internal stress, and causes warping deformation.

Solution: Uniform wall thickness: Keep the wall thickness of the entire cross-section as consistent as possible. Ideal wall thickness: 1.2mm-3.0mm for common industrial profiles, 3.0mm-8.0mm for large structural components. Smooth transition: If the wall thickness must change, a smooth arc transition should be adopted to avoid sharp corners.

2. Asymmetric or closed cavity design:

The reason is that an asymmetrical cross-section or the presence of a closed cavity will cause an uneven flow rate of metal when it passes through the die hole. Closed cavities require expensive "diversion molds", which are costly, structurally complex and have a short service life.

Solution: Optimize symmetry: Try to design the cross-section as symmetrical or nearly symmetrical as possible. "False gap" design: By changing the closed cavity to a semi-closed cavity with tiny gaps (such as 0.5-1mm), the mold difficulty is significantly reduced.

3. Excessive width-to-thickness ratio:

The reason is that the ratio of the width to the wall thickness of the profile is too large (such as wide and thin flat tubes), and problems such as wavy distortion and excessive planar clearance are very likely to occur during extrusion.

Solution: Add reinforcing ribs: Design reinforcing ribs on the back of the wide surface to enhance rigidity and stability.

 Issues Related to Surface Treatment and Solutions

1. Color difference

Reason: The alloy composition is uneven (especially elements such as Fe, Si, and Mn). The instability of the extrusion process (temperature and speed) leads to differences in grain size.

During anodizing, the temperature, concentration and voltage of the bath solution are unstable.

Solution: Specify alloys: Prioritize the use of alloys with excellent oxidation properties such as 6063 and 6061. Control the quality of the billet: Use high-quality aluminum rods with uniform composition.

2. Squeeze marks

Reason: The surface of the working band of the mold is not smooth or aluminum material adheres to it, leaving continuous straight lines on the surface of the profile. Subsequent surface treatments (especially anodizing) will magnify these defects.

Solution: Enhance the quality of mold polishing: Require mold factories to perform high-precision polishing on molds (such as mirror polishing). Mold nitriding treatment: Enhances the hardness and wear resistance of the mold surface and reduces aluminum adhesion. Design avoidance: Place the areas where patterns may appear on non-primary exterior surfaces.

3. Sharp edge burrs

Reason: Metal overflows from the die gap during extrusion, forming "flash", or burrs occur after Cnc Machining. It affects the hand feel, and during the spraying process, the coating does not cover the sharp edges adequately, resulting in early corrosion.

Solution: Design chamfering: Clearly specify on the drawing that all exposed edges undergo deburring and chamfering treatment (such as C0.3).

 Issues and Solutions related to subsequent processing and assembly

1. Processing deformation

The reason is that there is residual extrusion stress inside the profile. The machining process disrupts the original stress balance, causing the workpiece to release stress and deform. Improper clamping or unreasonable cutting parameters (speed, feed, depth of cut).

Solution: Stress Relief: Before machining, the profiles are subjected to "stretching and straightening" and "aging treatment" to effectively eliminate internal stress. Optimize processing technology: Adopt a multi-step and small-allowance processing program to gradually release stress. Improve the fixture design to avoid over-positioning.

2. Thread stripping/Insufficient strength:

The reason is that tapping directly on thin-walled Aluminum Profiles results in a small number of thread teeth, low connection strength, and repeated disassembly and assembly are prone to stripped threads.

Solution: Use steel wire thread inserts: Pre-embed stainless steel wire thread inserts at the positions where threads need to be installed, which greatly enhances the wear resistance and connection strength of the threads. Design and install nut grooves: Utilize the unique T-shaped grooves, rectangular grooves, etc. of the profiles, in combination with dedicated T-shaped nuts or slider nuts.

3. Assembly clearance or interference:

The reason is that when the profile is used as a frame structure, due to extrusion tolerance, bending deformation or thermal expansion and contraction, gaps may occur during assembly or it may not fit in.

Solution: Design reasonable tolerances: Understand the tolerance range of the extrusion process (such as GB/T 14846), and allow tolerance for non-mating dimensions. Design and assembly compensation: Use long round holes instead of round ones to leave room for installation and adjustment. Consider thermal expansion: For long-sized profile structures used in large temperature difference environments, expansion joints must be reserved.