Besides excessively high heating temperatures and rapid extrusion speeds, cracks in industrial aluminum profile extrusion processes are also caused by equipment malfunctions leading to uneven heating temperatures and drastic temperature gradients in the raw materials; and improperly designed multi-hole dies, such as those too close to the center, resulting in inadequate metal replenishment in the central area.
While common cracks in industrial aluminum profile extrusion are easily observed with careful inspection, minor extrusion cracks are difficult to detect with cursory observation. Detecting these minor extrusion cracks requires leveraging the difference in light reflection between smooth and cracked surfaces. This allows for easier observation and identification of the cracks. However, this requires experience and skill; failure to master this technique can easily lead to missed detections, which is one of the key reasons why cracks remain the leading cause of scrap in industrial aluminum profile extrusion products.
Industrial aluminum profiles have more complex cross-sections and a much larger surface area than aluminum profile bars, making them more prone to cracking. However, extrusion cracks in industrial aluminum profiles always first appear at the sharp corners of the panel because these corners experience the greatest frictional tensile stress and are most susceptible to cracking. The absence of cracks at the sharp corners generally indicates that cracks will not appear on the surface of the panel; this is an effective method for inspecting industrial aluminum profiles for extrusion cracks.
