Rigg för varmextrusion av metallspån

Sammanfattning: Extrusion is a design process where the material is heated and pressed through a metal disc, called a die. The opening through which the material is pressed through forms the material. There are two different types of extrusion: direct and indirect extrusion. Where the difference between them is how the material is pressed through the die. In direct extrusion, the material is pressed against the die with a so-called stem and the material is extruded in the same direction as the pressing force. Indirect extrusion is carried out by pressing the die against the material, the material is extruded in the opposite direction to the compressive force. One wish from the University of Gävle is to extrude chips from chip cutting machining of low-carbon steel. A hydraulic press and dies are available at Högskolan i Gävle, but equipment for holding the die is missing. Therefore, Högskolan i Gävle wants a rig that holds the die and allows extrusion. The objective of the work is to contribute with theoretical design proposals of a rig that allows extrusion. The aim is to develop a theoretical design proposal on a rig that allows extrusion of metal chips.The development of the rig began with a literature study where the goal was to get an understanding of the key components in the extrusion process. Based on the literature study, a list of what functions the rig must have was developed. Afterwards requirements for the rig were developed based on physical limitations for the press to be used, conditions that makes the rig safe to use and functionally requirements. With brainstorming, suggestions were made to achieve the functions of the rig. Each suggestion was compared against the requirements and the suggestions that meet all the requirements were combined with each other to produce different concepts. Two concepts was selected for further development resulting in two different models for direct extrusion and two for indirect extrusion.The work has resulted in four different rigs: one rig for direct and one for indirect extrusion, where each extrusion method has a rig that is two-part and one rig that is solid (not two-part). Where the two-part variant can allow easier access to the extruded bar. In both direct and indirect extrusion, the die will lie on the rigs which are hollow and the extruded rod will be extruded under the die. The chips to be extruded will be pre-pressed in a canister that is of the same material as the chips. The chips will then be extruded together with the canister. Upon direct extrusion, the canister will be centered against the die with a container and the canister will be pressed against the die with a stem. In the case of indirect extrusion, the container will be lowered over the cansiter and the matrix to center them against each other. The container will then be used as a stem and press the canister against the die.