Performance studies of deep cryogenic treated tungsten carbide cutting tool inserts on machining steel

Abstract

Machining studies were conducted on a carbon steel workpiece using both untreated and deep cryogenic treated P-20 tungsten carbide cutting tool inserts. The flank wear of deep cryogenic treated carbide tools is lower than that of untreated carbide tools on machining of C45 steel. The cutting force during machining of C45 steel is lower with the deep cryogenic treated carbide tools when compared with the untreated carbide tools. The surface finish produced on machining the C45 steel workpiece is better with the deep cryogenic treated carbide tools when compared with the untreated carbide tools.     

Analysis of energy distribution during electric discharge machining of tungsten carbide

Abstract

During electrical discharge machining (EDM) process, electrical energy is used for the machining of the components. Energy distribution in electrical discharge machining process is the distribution of input energy supplied during machining to various components. In order to improve the technological performance during EDM process, it is essential to understand the distribution of input energy in the entire system. An experimental study on the effect of EDM energy distribution parameter for tungsten carbide is presented. The copper tungsten electrode has been used for the study. Experiments have been performed in specially designed dielectric insulated tank. To minimise the energy wastage, workpiece as well as the electrode was covered with Teflon. Current and pulse duration have been selected as variable parameters. The objective of this study is to analyse the amount of electrical energy used for machining effectively. The detail of this study has been presented in this paper.     

Effect of processing parameters on structural features of tungsten carbide after electrical discharge machining (EDM)

Abstract

Tungsten carbide (WC) is an extremely hard material which is used extensively in the manufacturing of tools and dies. In the presence of cobalt as a binder its machining becomes a difficult task because of interfacial bonding. In the EDM process, where electrical energy is used for the machining of the substance, the heat generated due to the plasma is responsible for removal of the substance at the interface. The heat generated is conducted differentially because of the composite structure of the tungsten carbide cermet. In order to improve the technological performance it is essential to understand the morphological features of tungsten carbide after machining. The studies have been conducted using different machining parameters. The objective of this study is to analyse the impact of machining parameters on the morphology of tungsten carbide suitable to withstand impact load on press forging for small components during operation. Experiments have been performed with the specially designed fixtures with proper flushing arrangements, to avoid arcing during the process. WC of P20 grade which is one of the most suitable grade substances to withstand load after EDM, has been used as work piece material for the entire study. Copper, graphite and copper tungsten electrodes have been used for the present study. The morphological features were studied with the help of the scanning electron microscope (SEM). It was observed that structural features varied with variation in electrode under similar experimental conditions. Phenomenon of such structures is discussed at length. The formations of cracks on WC have also been studied in detail. The detail of this study is presented in the paper.     

Fabrication and cutting performance of cemented tungsten carbide micro-cutting tools

We have developed cemented tungsten carbide (CTC) micro-cutting tools of 3 μm diameter by electrical discharge machining (EDM). Microdrilling and micromilling were carried out using the developed tools, and their cutting performance was investigated. Cutting was performed in free-cutting brass plates. Ultrasonic oscillation was employed to lower the cutting resistance. As a result, holes and a slot of 3 μm depth were successfully fabricated using tools made of CTC with 0.6 μm grain size, indicating that successful cutting with 3 μm-diameter tools was accomplished for the first time. Furthermore, CTC with 90 nm grain size was used as a tool material to improve the tool breakage resistance and tool form accuracy. The drilling performance of tools made of this ultrafine-grain-sized CTC was also investigated and found to exhibit a considerably improved average tool life.     

灯座三角盘硬质合金多工位级进模设计

分析了灯座三角盘的工艺特点,确定了排样方案及模具的结构,采用了快换式、分体式凸模结构和防误送的检测装置,冲压制件精度高,模具使用寿命高,便于维修和维护。