6533b82dfe1ef96bd1290a9f

RESEARCH PRODUCT

Grinding Tungsten Carbide Used for Manufacturing Gun Drills

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This paper presents a study of grinding cemented carbide DK460UF (91 % WC and 9 % Co), a material used to produce cutting tools with solid cutting edges. The aim is to establish the manufacturing conditions that lead to high surface quality. A model of the main factors that influence the grinding process is presented first. Following that, grinding wheel wear and surface roughness are analysed. Grinding wheel wear is studied in experimental conditions under which small diameter gun drills were sharpened with two diamond grinding wheels of different grain sizes. Finally, the wear curve can be made. The "G ratio" is used to characterise the performance of the grinding process. Next, the experimental research examines how independent parameters, depth of cut, feed, grit, and speed influence roughness. The influence of the grinding wheel wear on roughness is also studied. The aspect of ground surfaces is examined by using a scanning electron microscope (SEM). The experimental study allowed the determination of the required grinding wheel grit (46 nanom) and the optimum processing parameters (depth of cut ap = 0.01 mm, feed = 0.005 mm/rev, cutting speed v = 55 m/s) to obtain the imposed surface roughness for cutting tool surfaces (Rz = 0.3 nanom). The maximum allowed radial wear (r) of the grinding wheel is 30 nanom. Predmet raziskave je analiza procesa brušenja karbidne trdine DK460UF (91 % WC in 9% Co), iz katere se izdelujejo rezalna orodja z neprekinjenimi rezalnimi robovi. Cilj je opredelitev izdelovalnih pogojev, ki privedejo do kakovostne površine. Procese brušenja volframovega karbida za rezalna orodja je treba optimizirati zato, ker njihove aktivne površine zahtevajo določene kakovostne lastnosti za enostavnejše odstranjevanje odrezkov in daljšo življenjsko dobo orodja. Največja dovoljena hrapavost aktivne površine je Rz = 0,3 nanom. Za ugotovitev optimalnih parametrov za izdelavo dobre površine je bila najprej opravljena teoretična študija, v kateri so bili opredeljeni glavni dejavniki, ki vplivajo na kakovost površin, na podlagi te študije pa je bil nato zasnovan še eksperiment.