Papers by Keyword: Chip Curl

Abstract: Conventionally, chip breakers are utilized for efficient chip disposal, where the chip is assisted to curl up and broken into pieces. However, this approach may not work effectively in cutting of highly-ductile materials such as low-carbon steels or heat-resistant alloys. The problem of chip jam may frequent occur especially in finishing operation, since the chip is thin and flexible [1]. In order to suppress chip-jam, the authors have proposed a new method, called the ‘chip-guiding turning’ [2]. Fig. 1 shows the concept of chip-guiding turning briefly. In this method, instead of breaking the chip, it is continuously guided to a desired direction for continuous disposal.

Abstract: In the process of turning high-temperature and high-strength steel, it is an effective method for chip breaking with complicated groove insert. In this paper, chip breaking mechanism is analyzed using the coated complicate groove insert for cutting high-temperature and high-strength steel. The model of chip curl radios is constructed though analyzing the effect of complicated groove insert on chip formation. The mathematical formulation of chip section profile coefficient is built through analyzing influential effect of complicated groove on chip section profile. The chip breaking model is developed according to chip-breaking criterion. Finally, a full experimental validation of the model is presented for chip breaking when the workpiece is high-temperature and high-strength steel, 2.25Cr-1Mo-0.25V. The tested results show the chip breaking model is reasonable, and the optimization cutting parameters are obtained.

Abstract: The tool-chip contact length, as an important parameter controlling the geometry of tool crater wear and understanding chip formation mechanism, is widely investigated in machining. The aim of this paper is to study the influence of chip curl on tool-chip contact length by means of experimental observations with high cutting speed. The relationship between tool-chip contact length, chip radius of curvature and uncut chip thickness was investigated. Experimental results show the effect of increasing spiral chip radius on tool-chip contact length with low uncut chip thickness in high speed machining.

Abstract: Primary heat dissipation method of IC Chip is still air-cooling at present. This paper presents a new machining method of air-cooled plate fin heat sinks, namely orthogonal planing. The surface of plate fins machined by this method are rough enough to augment its specific surface area; the rough surface can also disturb laminar sub-layer of turbulent thermal boundary layer, thus the thermal resistances of thermal boundary layer are reduced. Therefore, heat dissipation efficiency of heat sink can be enhanced further. The focus of plate fin heat sinks forming by orthogonal planing is how to machine flat chips. A new pattern of chip curl that is called down-curl can be observed when rake angle of tool is rather large and cutting thickness is very thin. As cutting thickness increases, down-curl chips become flat and then up-curling. There is a transition area that chips are not curled between down- and up-curl. The conditions that chips are not curled are obtained through investigating influences of rake angle and cutting thickness on chip curl, and flat plate fins with rough surface are produced.