Study on the Behavior of the Cast-Iron Bonded Grinding Wheel to Machining Properties of Hard and Brittle Materials

2007 ◽  
Vol 24-25 ◽  
pp. 229-232
Author(s):  
S.L. Ma ◽  
Wei Li ◽  
Cong Rong Zhu ◽  
J. Zhang ◽  
H.C. Ye
Keyword(s):  
Grain Size ◽  
Cast Iron ◽  
Tungsten Carbide ◽  
Surface Quality ◽  
Ground Surface ◽  
Grinding Wheel ◽  
Different Grain Size ◽  
Grinding Efficiency ◽  
Machining Properties

Tungsten carbide which is a hard and brittle material was ground by cast-iron bonded diamond wheel with ELID (Electrolytic In-Process Dressing) technique, for the purpose of getting high efficiency, super-precision machining. Three kinds of cast-iron bonded diamond wheels with different grain size were adopted to get different grinding efficiency and surface quality of workpieces. The grinding properties of cast-iron bonded grinding wheels with different grain size and the ground surface quality of tungsten carbide are discussed in this paper. The experiment results indicate that, under the same feeding amount, the grinding efficiency of the wheel with bigger grain size is higher, and it could make the dimension accuracy of the workpiece controllable, but the wheel with smaller grain size could get better ground surface quality. The two grinding phases are decided by the ratio between the size of abrasive grain and the thickness of the oxide layer on the grinding wheel.

New Ways at the Fine Grinding

2013 ◽  
Vol 581 ◽  
pp. 255-260 ◽  
Author(s):  
Martin Novák
Keyword(s):  
Surface Quality ◽  
Traditional Approach ◽  
Surface Profile ◽  
Ground Surface ◽  
Cutting Parameters ◽  
Grinding Wheel ◽  
Roughness Parameters ◽  
Machined Parts ◽  
Machining Operations

The traditional approach to grinding is to operate within the limits of surface quality. The requirements for surface quality in grinding are higher than those in other common machining operations such as turning and milling. The surface quality of machined parts is very important for precise production and assembly. When we focus on roughness parameters after grinding, we can establish the limits of these parameters for typical grain materials: Al2O3, SiC, CBN, SG and others. Increasing demands on accuracy and quality of production leads to research concerned with the properties of these materials and the surface quality after grinding. This paper shows new possibilities for the ground surface with focus on surface roughness obtained under varying combinations of cutting conditions. The influence of the grinding wheel, cutting parameters and coolant on higher surface quality is assessed by roughness parameters Ra, Rz, Rt and the Material portion of a surface profile. These high-precision ground surfaces are shown to have a Nanometres (10-9) unit topography demonstrating that the process is able to replace other finishing technologies such as superfinishing or honing.

Grinding Performance of Permeated Grinding Wheel

2011 ◽  
Vol 189-193 ◽  
pp. 121-124
Author(s):  
Wei Li ◽  
Bin Hu ◽  
Ming Ming Ma
Keyword(s):  
Surface Quality ◽  
Solid Lubricant ◽  
Ground Surface ◽  
Grinding Force ◽  
Grinding Wheel ◽  
Grinding Temperature ◽  
Chemical Additives ◽  
Wheel Surface ◽  
Lubrication Film ◽  
Grinding Efficiency

The permeated grinding wheel was a new kind of grinding wheel, which was permeated by the chemical additives and solid lubricant into the interior gaps of the grinding wheel. Therefore, the grinding wheel can form a lubrication film on the surface of the grinding wheel. This grinding wheel has some good features, such as lower grinding temperature, smaller grinding force, higher life of the grinding wheel, and can prevent the adhesion of chip onto the grinding wheel surface. The experimental results indicate that the ground surface quality and grinding efficiency have been remarkably improved for more hard-to-cut materials.

Focus on Carbide-Tipped Circular Saws when Cutting Stainless Steel and Special Alloys

2015 ◽  
Vol 1114 ◽  
pp. 13-21 ◽  
Author(s):  
Mario Rosso ◽  
Ildiko Peter ◽  
Federico Gobber
Keyword(s):  
Grain Size ◽  
Wear Resistance ◽  
Tungsten Carbide ◽  
Cobalt Content ◽  
Coarse Grained ◽  
Cemented Carbides ◽  
Grinding Wheel ◽  
Large Power ◽  
Circular Saw ◽  
Circular Saws

Circular saw blades are used exclusively for cut-off work, ranging from small manual feed operations, up to very large power fed saws commonly used for sectioning stock as it comes from a rolling mill or other manufacturing processes for long products. The teeth profile, as well as the tooth configuration are of fundamental importance for the blade performances; through a combination of blade rigidity and grinding wheel condition a good quality surface finish is attained for tools of commercial standard. The materials used for the production of circular saw blades are ranging from high speed steel to cemented carbides. In particular, cemented carbides, being characterized by high hardness and strength, are used in applications where materials with high wear resistance and toughness are required. The main constituents of cemented carbides are tungsten carbide and cobalt. Tungsten carbide imparts the alloys the necessary strength and wear resistance, whereas cobalt contributes to the toughness and ductility of the alloys. The WC-Co alloys are tailored for specific applications by the proper choice of tungsten carbide grain size and the cobalt content. The grain size of the tungsten carbide in WC-Co varies from about 40 µm to around 0.3 µm, the cobalt content from 3 to 30 wt%. The coarse grained hardmetals are mainly used in mining applications, the smallest grain size being about 3 µm and the minimum cobalt content 6 wt%. The grain size of tungsten carbide in the metal cutting industry, as well as for universal applications lies in the range of 1-2 µm. However, with the advent of near net shape manufacturing and thin walled components, the use of submicron carbide is growing, since their high compressive strength and abrasive wear resistance can be used to produce tools with a sharp cutting edge and a large positive rake angle.In this invited paper, a general overview on the actual trends in the choice of the best material when cutting special alloys will be presented and discussed. Based on the recent and past literature some examples of their up-to-date application, such as circular saws used to cut stainless steels and some high strength alloys, are talk over.

Evaluation of the Working Surface of the Grinding Wheel Using Speckle Image Analysis

2015 ◽  
Author(s):  
Arunachalam Narayanaperumal ◽  
Vijayaraghavan Lakshmanan
Keyword(s):  
Surface Quality ◽  
Surface Condition ◽  
Grinding Wheel ◽  
Optical Parameters ◽  
Wheel Surface ◽  
Wheel Wear ◽  
Speckle Image ◽  
Periodic Monitoring ◽  
Grinding Machine

The surface quality of the ground components mainly depends on the surface condition of the grinding wheel. The surface condition of the grinding wheel changes with grinding time due to wheel wear and loading. The excessive wear and loading increases the cutting force and the temperature. This in turn affects the quality of the produced component. Hence periodic monitoring of the grinding wheel surface is essential to avoid the production of the defective components. In this paper, an attempt is made to study the changes in the grinding wheel surface condition using the laser scattered images. The simple speckle imaging arrangement is fabricated and fitted into the grinding machine to capture the images of the grinding wheel after each 100 passes. The fresh wheel expected to scatter more light due to higher roughness and porosity. On the other hand, the completely glazed and worn-out wheel scatters the light less due to smoother surface. Thus, speckle image intensity distribution captures the changes in the grinding wheel surface condition. The optical parameters evaluated from the speckle images clearly indicating the changes in the grinding wheel condition. This method can be utilized to evaluate the grinding wheel condition to improve the surface quality of the component produced.

scholarly journals Surface Quality Evaluation of Various Metals After Grinding with Aluminum Oxide Grinding Wheel

2020 ◽  
Vol 9 (1) ◽  
pp. 25-31
Author(s):  
Rosemar Batista Da Silva ◽  
Giordano Francis Vieira ◽  
Letícia Cristina Silva ◽  
Carlos Alberto Damião ◽  
Rodrigo De Souza Ruzzi ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Cast Iron ◽  
Aluminum Oxide ◽  
Surface Quality ◽  
Gray Cast Iron ◽  
Gray Cast ◽  
Surface Finishing ◽  
Depth Of Cut ◽  
Grinding Wheel ◽  
Machined Surfaces

Different metals can respond differently when grinding using the same abrasive grinding wheel, especially in terms of surface quality. In this context, this work aims give a contribution to the metalworking industry by presenting the results of surface finishing after grinding the following metals: VP Atlas steel grade, Gray Cast Iron and two superalloys, Inconel 718 and Ti-6Al-4V. Tests were performed with the aluminum oxide grinding wheel and with following parameters: cutting speed of 37.6 m/s and workspeed of 10 m/min. Two values of depth of cut (15 μm and 30 μm) were tested. The surface roughness (Ra and Rz parameters) were analyzed and SEM images of the machined surfaces were taken and analyzed in order to identify the cutting mechanisms and provide better results discussion. The results showed that the surface roughness increased with the depth of cut; Ra values kept below 0.48 μm for all metals tested. Regarding the machined surface quality, some cracks were observed on the gray cast iron and Ti-6Al-4V surfaces, thereby indicating their relative lower grindability compared to VP Atlas steel under the investigated conditions. No visual thermal damage was observed in the machined surfaces of the samples.

scholarly journals Surface Layer Properties of Low-Alloy High-Speed Steel after Grinding

2016 ◽  
Vol 10 (4) ◽  
pp. 275-279
Author(s):  
Jan Jaworski ◽  
Tomasz Trzepieciński
Keyword(s):  
Surface Layer ◽  
High Speed ◽  
High Speed Steel ◽  
Grinding Wheel ◽  
Grinding Temperature ◽  
Grinding Parameters ◽  
Micro Cracks ◽  
Secondary Austenite ◽  
Grinding Efficiency

AbstractInvestigations of the surface layer characteristics of selected kinds of low-alloy high-speed steel after grinding were carried out. They were carried out on the flat-surface grinder with a 95A24K grinding wheel without cooling. The influence of grinding parameters was defined especially for: the quantity of secondary austenite, surface roughness, microhardness and grinding efficiency with a large range of grinding parameters: grinding depth 0.005–0.035 mm, lengthwise feed 2–6 m/min, without a cross-feed on the whole width of the sample. It was found that improvement of grinding properties of low-alloy high-speed steels is possible by efficient selection of their chemical composition. The value of the grinding efficiency is conditioned by grinding forces, whose value has an impact on the grinding temperature. To ensure high quality of the tool surface layer (i.e. a smaller amount of secondary austenite, lack of wheel burn and micro-cracks) in the case of sharpening of tools made of low-alloy high-speed steel, the grinding temperature should be as low as possible.

Experimental Study on Ultrasonic Vibration Dressing Wheel

2010 ◽  
Vol 135 ◽  
pp. 260-264
Author(s):  
Dao Hui Xiang ◽  
Xin Tao Zhi ◽  
Guang Xi Yue ◽  
Bo Zhao ◽  
Q.T. Fan
Keyword(s):  
Surface Quality ◽  
Ultrasonic Vibration ◽  
Ground Surface ◽  
Surface Characteristics ◽  
Axial Direction ◽  
Grinding Wheel ◽  
Workpiece Surface ◽  
Surface Burn ◽  
Grinding Conditions ◽  
Strict Requirement

Excellent wheel dressing technology can ensure the ground surface quality effectively. Because precision machining has a strict requirement on the wheel dressing, the wheel dressing with ultrasonic vibration was adopted, and the device of ultrasonic vibration dressing was also designed in this paper. On the base of analysis mechanism of ultrasonic vibration dressing wheel, the grinding experiment was carried out in different dressing conditions. The surface characteristics of ultrasonic dressing wheel and the influence of different dressing parameters on the workpiece surface quality were studied. Furthermore, the optimal dressing parameters have been obtained. The experiment results indicate that the micro cutting edge of grinding wheel distribute sparsely in circumferential directional but densely in axial direction in the condition of ultrasonic dressing, and it is particular characteristic of ultrasonic dressing. When the dressing and grinding conditions are suitable, the workpiece surface roughness can be reduced, but the conditions are not arbitrary. At the same time, the workpiece surface burn can be effectively reduced, even if the larger grinding depth is used during the grinding process.

Effect of the Grinding Oil Type on CBN Grinding Wheels Performance

2009 ◽  
Author(s):  
Taghi Tawakoli ◽  
Abdolreza Rasifard ◽  
Alireza Vesali
Keyword(s):  
Heat Resistance ◽  
Surface Quality ◽  
Grinding Wheel ◽  
Work Piece ◽  
Grinding Process ◽  
Grinding Wheels ◽  
Grinding Forces ◽  
Vitrified Cbn ◽  
Oil Type

The efficiency of the grinding process highly depends on the coolant lubricant used. In grinding with CBN grinding wheels grinding oils are used increasingly. In the last decade new grinding oils based on different oil types are brought into the market, whose effect on the CBN grinding wheels performance until now not sufficiently been investigated. The Institute of Grinding and Precision Technology (KSF) investigated the influence of four different grinding oils on the performance of vitrified CBN grinding while grinding of 100Cr6 (M.-No. 1.3505), which is a heat-treatable steel with a very good grindability, and Nimonic A80, which is a difficult to grind heat-resistance superalloy. The obtained results show that the performance of the vitrified CBN grinding wheels—while using grinding oil as coolant lubricant—regarding the quality of the work piece surface, the grinding forces as well as the wear of the grinding wheel, highly depend on the viscosity of the grinding oil. Moreover, the results show that the surface quality and the grinding forces while using different grinding oils depend significantly on the work piece material.

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