Study on Grinding Technology of Electrical Discharge Grinding of Curve Edge Polycrystalline Diamond

2006 ◽  
Vol 304-305 ◽  
pp. 206-209 ◽  
Author(s):  
Gang Liu ◽  
Ming Chen ◽  
Z.G. Hu ◽  
X.F. Zhu ◽  
H. Xu ◽  
...  

PCD tools, especially curve edge PCD compound tools are used widely in machining nonferrous and non-metal materials with high efficiency and precision because of their excellent cutting properties. But high quality grinding of PCD tools is the uppermost obstacle in application because there are great difficulties to profile and sharpen edge in grinding, especially for milling cutter and drill with curve edge. This paper studied technology of wire EDG curve edge PCD compound tools by wire electrical discharge grinding machine with five-axis CNC system. The grinding quality was evaluated by scanning electron microscope (SEM) and roughometer. Three steps processing technique (roughing, finishing and fine finishing) and optimal process parameters of wire EDG PCD tools were recommended after considering synthetically the surface quality, precision and machining efficiency. The results met the requirement of high surface quality, precision and efficiency. This paper also applied successfully the optimal technology to grind a PCD milling cutter with outer and inner blade by electrical discharge grinding machine with five-axis CNC system. By the optimal parameters, the process yielded high precision of ±4.3µm and low roughness of 0.30µm. Experiment results have great practical significance to the high precise and efficient wire EDG of PCD tools.

Author(s):  
M. Zulafif Rahim ◽  
Songlin Ding ◽  
John Mo

Electrical discharge grinding (EDG) is becoming more prevalent in the manufacturing of polycrystalline diamond (PCD) tools. This paper concerns investigation of the effects of machining parameters, as well as finishing in-feed, to the surface quality obtained when using EDG to erode PCD. With the aid of the morphological findings, different PCD erosion mechanisms are discussed. Experimental results demonstrated that the eroded surface quality of PCD was significantly affected by the selected parameters. High temperature due to the erosion process resulted in the partial conversion of diamond to graphite phase under the surface. Higher finishing in-feed produced better surface quality and caused lower surface graphitization and lower tensile residual stress. A model for the thermal stress prediction was developed and found to have good agreement with the experimental findings.


2012 ◽  
Vol 538-541 ◽  
pp. 1316-1321
Author(s):  
Shao Hua Shi ◽  
Pei Qing Ye ◽  
Chen Xi Fang

Polycrystalline Diamond (PCD) tools are widely used while machining wood-based composites because of its outstanding hardness, thermal conductivity and abrasive resistance. However, the above mentioned beneficial properties such as super hardness also cause problems in manufacturing PCD tools using traditional process methods. The main problem now in manufacturing PCD tools is the low efficiency and difficulties while manufacturing PCD tools with complex curved surface. To manufacture PCD tools with complex curved surface more efficiently, in this paper, the mechanical structure, hardware circuit and software system of five-axis EDG CNC system are introduced. To satisfy the unique requirements of EDG, a proper mechanical structure of 5 CNC controlled axis and 2 manual axis are given, as well as the design of hardware circuit of EDG based on PCI Bus. The software system which is designed based on RT-Linux is divided into four modules: real-time cyclical tasks module, real-time gusty tasks module, non real-time tasks module and EDG process database. , This paper gives out the solutions of the specific functions of this special CNC system, including automatic measurement, automatic programming, automatic electrode wear compensation, and detection and control of spark gap. The detailed structure and organization of the software system is also provided. At last, through actual cutting experiments of woodworking PCD tools, the correctness and practicality of this system is verified.


2014 ◽  
Vol 543-547 ◽  
pp. 3943-3946
Author(s):  
Gang Gou ◽  
Yong Liu ◽  
Zhong Yuan Lin

Aiming at the finishing of small hole of difficult-to-machine materials such as carbide, etc, this paper presented a new low speed electrical discharge grinding (EDG-LS) processing method, in which a machine tool accessory was equipped on WEDM-LS to realize the grinding process. Through the analysis of orthogonal test, the key factors affecting technological effect were discussed in the processing of EDG-LS, and the influence of average gap voltage, average gap current and workpiece speed on machining dimension and surface quality were elaborated respectively. It is of importantly theoretical and practical significance to seek better technology parameter in EDG-LS.


2021 ◽  
Vol 5 (2) ◽  
pp. 34
Author(s):  
Guangxian Li ◽  
Ge Wu ◽  
Wencheng Pan ◽  
Rizwan Abdul Rahman Rashid ◽  
Suresh Palanisamy ◽  
...  

Polycrystalline diamond (PCD) tools are widely used in industry due to their outstanding physical properties. However, the ultra-high hardness of PCD significantly limits the machining efficiency of conventional abrasive grinding processes, which are utilized to manufacture PCD tools. In contrast, electrical discharge grinding (EDG) has significantly higher machining efficiency because of its unique material removal mechanism. In this study, the quality and performance of PCD tools machined by abrasive grinding and EDG were investigated. The performance of cutting tools consisted of different PCD materials was tested by high-speed turning of titanium alloy Ti6Al4V. Flank wear and crater wear were investigated by analyzing the worn profile, micro morphology, chemical decomposition, and cutting forces. The results showed that an adhesive-abrasive process dominated the processes of flank wear and crater wear. Tool material loss in the wear process was caused by the development of thermal cracks. The development of PCD tools’ wear made of small-sized diamond grains was a steady adhesion-abrasion process without any catastrophic damage. In contrast, a large-scale fracture happened in the wear process of PCD tools made of large-sized diamond grains. Adhesive wear was more severe on the PCD tools machined by EDG.


2014 ◽  
Vol 1025-1026 ◽  
pp. 628-632 ◽  
Author(s):  
Mohammad Zulafif Rahim ◽  
Song Lin Ding ◽  
John Mo

Electrical discharge grinding (EDG) is an advanced machining process and can be utilised to fabricate complex geometry of PCD tools. However, the PCD removal mechanism in this process is complicated. This study was carried out to understand the difference in PCD surface structure with difference EDG polarities. The study revealed that the finishing process with negative polarity is the reason for the porous structure on the surface. Further analysis on the chemical element and carbon structure were implemented as the morphological examination of the surface.


2018 ◽  
Vol 8 (8) ◽  
pp. 1353
Author(s):  
Tao Chen ◽  
Fei Gao ◽  
Suyan Li ◽  
Xianli Liu

Carbon fiber reinforced plastic (CFRP) is typically hard to process, because it is easy for it to generate processing damage such as burrs, tears, delamination, and so on in the machining process. Consequently, this restricts its wide spread application. This paper conducted a comparative experiment on the cutting performance of the two different-structure milling cutters, with a helical staggered edge and a rhombic edge, in milling carbon fiber composites; analyzed the wear morphologies of the two cutting tools; and thus acquired the effect of the tool structure on the machined surface quality and cutting force. The results indicated that in the whole cutting, the rhombic milling cutter with a segmented cutting edge showed better wear resistance and a more stable machined surface quality. It was not until a large area of coating shedding occurred, along with chip clogging, that the surface quality decreased significantly. At the stage of coating wear, the helical staggered milling cutter with an alternately arranged continuous cutting edge showed better machined surface quality, but when the coating fell off, its machined surface quality began to reveal damage such as groove, tear, and fiber pullout. Meanwhile, burrs occurred at the edge and the cutting force obviously increased. By contrast, for the rhombic milling cutter, both the surface roughness and cutting force increased relatively slowly.


Author(s):  
Barnabás Zoltán Balázs ◽  
Márton Takács

Micro-milling is one of the most essential technologies to produce micro components, but due to the size effect, it has many special characteristics and challenges. The process can be characterised by strong vibrations, relatively large run-out and tool deformation, which directly affects the quality of the machined surface. This paper deals with a detailed investigation of the influence of cutting parameters on surface roughness and on the special characteristics of micro-milled surfaces. Several systematic series of experiments were carried out and analysed in detail. A five-axis micromachining centre and a two fluted, coated carbide micro-milling tool with a diameter of 500 µm were used for the tests. The experiments were conducted on AISI H13 hot-work tool steel and Böhler M303 martensitic corrosion resistance steel with a hardness of 50 HRC in order to gain relevant information of machining characteristics of potential materials of micro-injection moulding tools. The effect of the cutting parameters on the surface quality and on the ratio of Rz/ Ra was investigated in a comprehensive cutting parameter range. ANOVA was used for the statistical evaluation. A novel method is presented, which allows a detailed analysis of the surface profile and repetitions, and identify the frequencies that create the characteristic profile of the surface. The procedure establishes a connection between the frequencies obtained during the analysis of dynamics (forces, vibrations) of the micro-milling process and the characterising repetitions and frequencies of the surface.


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