Uneven Wall Thickness of Extrusion Products
Extrusion is a metalworking process in which high temperature, pressure and speed are applied to metal alloys to conduct plastic deformation. It is widely used in metalworking, as it is cheaper and can produce components with greater complexity and strength. The process involves pushing metal, in a heated and pressurized state, through a die, which is a slightly tapered opening. The main challenge of extrusion processes is achieving part symmetry, particularly when it comes to wall thickness. If a part is not of uniform wall thickness then it can show up in the consumer product in the form of defects in the finished product.
Uneven wall thickness in an extrusion process can be caused by a number of things. One of the major factors is incorrect die design. If the die and its associated components are not designed properly, it can cause the part to be punched in different areas of the extrusion. This can create uneven wall thickness, as the sections of the part that are punched with more force tend to extrude larger than the remaining sections. Poor die alignment can also lead to uneven wall thickness. If the die isnt properly aligned with the extrusion press, parts can be extruded asymmetrically, leading to parts with uneven wall thickness.
Flaws in the material itself can also contribute to uneven wall thickness. If the material is pure and homogenous then it will produce parts of uniform thickness. However, if the material contains impurities or inconsistencies then the extrusion process can push those inconsistancies through the die, creating parts with uneven wall thickness. The presence of voids or air pockets in the material can also contribute to uneven wall thickness, as any areas of high pressure will push the material around the voids and lead to uneven surfaces.
Finally, welding defects can cause uneven wall thickness in parts. If welds contain holes, voids, or cracks, the pressure created during extrusion can fill the defects and instead of a uniform wall thickness the parts could have areas of thicker and thinner wall thicknesses.
To correct or prevent problems with uneven wall thickness in extrusion processes, the following steps can be taken:
First, the die should be designed and adjusted properly. Make sure the die is properly aligned with the press and that the die and press are correctly set up.
Next, make sure the material used is free of impurities and inconsistencies. Any inconsistencies or impurities present in the material will be pushed through the die, resulting in uneven wall thickness.
Finally, ensure that welding defects have been corrected prior to extrusion. Any faulty welding can be pushed through the die and eventually create a defective part.
By following the steps above, extrusion processes can produce parts of balanced wall thickness. It is important to note, however, that there is no guarantee that parts produced with a perfectly balanced die, perfectly balanced material and perfectly welded components will perfectly symmetrical parts. Parts produced with perfectly balanced components and material can still suffer from uneven wall thickness due to the effects of pressure during the extrusion process. Nevertheless, taking the steps outlined above will reduce the likelihood of uneven wall thickness.
