Effect of wall thickness difference and aspect ratio
The uneven wall thickness of the section increases the difficulty of extrusion, the greater the difference in wall thickness, the greater the difficulty of extrusion, and the difficulty increases significantly when the difference in special wall thickness is more than 3 times. It is easy to cause products to produce defects such as twisting, bending, and uneven mechanical properties.
Due to the difference in wall thickness, sometimes it is difficult for a product with a small difficulty coefficient to produce a qualified finished product. In addition, the wall thickness difference also has an impact on the surface quality of the product, such as oxidation in the profile wall thickness difference transition position surface has a shadow, there is a feel and so on. We can make some changes in the design of the profile, such as adding some decorative patterns to the transition surface or increasing the inner corner rounding, etc., which can alleviate or avoid the above problems.
For some U-shaped or V-shaped open products, the ratio of depth to width (called the aspect ratio), the greater the ratio, the greater the difficulty. When the depth-to-width ratio is more than 2, it will make the opening size tolerance difficult to control, and it is easy to produce a closing or opening, which increases the difficulty of the stretching process. In order to ensure that the opening does not shrink too much when stretching, it is necessary to add a special pad at the opening.