Kalıp girişinin ekstrüzyon edilebilirlik üzerindeki etkisi

Aluminum has been preferred in many areas such as the construction, automotive and aerospace industries due to its lightweight, strength, ductility, recycle, corrosion resistance and conductivity. Aluminum and its alloys can be formed by many manufacturing methods with the developing technology. One of the common method is extrusion process to shape the aluminum. In the extrusion process, a workpiece is pushed by a stem towards the die opening giving the product shape. Material flow in the extrusion is important due to obtain the product with the acceptable tolerances. The material flow is affected by extrusion type, extrusion speed, extrusion temperature, die design and extrusion ratio. One of the most important factors in the process of extrusion, the optimum die design, provides higher product quality and lower deformation load. In this study, the effect of the die profile is examined by a finite element based software DEFORM 3D to determine the most suitable die design. Different die profiles (conical die, concave die, convex die, reverse S die and S die types) were modeled and simulated to analyze and compare how the die design type effects on the extrudability. The change of effective stress and extrusion temperature with the die profile type was examined depending on the extrusion time, and the cause of these changes were explained. As a result, the most suitable die type between the mentioned die profiles was analyzed for the production of the same extrudate. Different results were obtained for each die profile type. The initial billet temperature was 480 ºC and the significant increase in the extrusion temperature was occurred in the beginning of the extrusion. The maximum workpiece temperature was observed in the convex die with a value of 524 ºC while it was only 506 ºC for the concave die type. The temperature increase for convex die was higher than the other die types even if the initial billet temperature (480 ºC) and friction values were the same for the all simulated die profiles. The reason of this is related with the material flow which was not suitable. The material flow from the best to the worst die type was occurred as the concave die, the S die, the conical die, the reverse S die and the convex die, respectively. On the other hand, the effective stress occurred in the workpiece was also examined in the scope of the study with the performed simulations. It was observed that the effective stress in the workpiece was increased during the extrusion time without sharpened changes in the beginning of the extrusion at where the billet is just started to be forced towards the die opening.