Influence of Machining Parameters on Machine Tool Loads at Rotary Ultrasonic Machining of Cubic Boron Nitride

2016 ◽  
Vol 686 ◽  
pp. 155-160
Author(s):  
Marcel Kuruc ◽  
Juraj Vagovský ◽  
Jozef Peterka

Poly-crystalline cubic boron nitride (PCBN) is one of the hardest known material. Therefore only advanced methods are able to treat such material. Advanced machining methods, proper for machining of hard and brittle materials (such as glass and ceramics) include rotary ultrasonic machining (RUM). However, high hardness of workpiece cause higher loads and it could negatively affect achievable accuracy and surface topography. Machine loads are affected by both: machined material and machining parameters. This contribution investigates influence of machining parameters, such as spindle speed, feed rate and depth of cut, on loads of machine tool during machining of PCBN by rotary ultrasonic machining.

2016 ◽  
Vol 686 ◽  
pp. 180-185 ◽  
Author(s):  
Marcel Kuruc ◽  
Martin Kusý ◽  
Vladimír Šimna ◽  
Jozef Peterka

Poly-crystalline cubic boron nitride (PCBN) is one of the hardest known material. Therefore only advanced methods are able to treat such material. Advanced machining methods, proper for machining of hard and brittle materials (such as glass and ceramics) include rotary ultrasonic machining (RUM). This method should achieve high precision and low surface roughness (at least during machining of materials such as ceramics). Achievable roughness is affected by machined material and machining parameters. This contribution investigates influence of machining parameters, such as cutting speed and feed rate, on resultant surface roughness during machining of PCBN by rotary ultrasonic machining.


Author(s):  
Marcel Kuruc ◽  
Jozef Peterka

Abstract Poly-crystalline cubic boron nitride (PCBN) is one of the hardest material. Generally, so hard materials could not be machined by conventional machining methods. Therefore, for this purpose, advanced machining methods have been designed. Rotary ultrasonic machining (RUM) is included among them. RUM is based on abrasive removing mechanism of ultrasonic vibrating diamond particles, which are bonded on active part of rotating tool. It is suitable especially for machining hard and brittle materials (such as glass and ceramics). This contribution investigates this advanced machining method during machining of PCBN.


2015 ◽  
Vol 766-767 ◽  
pp. 649-654
Author(s):  
A. Srithar ◽  
K. Palanikumar ◽  
B. Durgaprasad

The machining of hard turning is performed on hardened steel in the range of 45 to 68 Rockwell hardness using a variety of tool materials such as Polycrystalline cubic boron nitride (PCBN) , Polycrystalline diamond (PCD) and Cubic boron nitride (CBN). It is an alternative to conventional grinding process is a flexible and effective machining process for hardened metals and hence broadly used in various applications such as dies, moulds, tools, gears, cams, shafts, axles, bearings and forgings. Although the process is performed within small depth of cut and feed rates, estimates to reduce machining time as high as 60 % in hard turning. This paper discusses the importance of hard turning of AISI D2 steel. In this study, Experimental investigations are carried out on conventional lathe using prefixed the cutting conditions. The responses studied in the investigation are cutting forces (Fa, Ft and Fz). The cutting parameters considered for the investigation are cutting speed, feed and depth of cut. The influence of machining parameters on response is studied and presented in detail.


1995 ◽  
Vol 117 (2) ◽  
pp. 142-151 ◽  
Author(s):  
Z. J. Pei ◽  
D. Prabhakar ◽  
P. M. Ferreira ◽  
M. Haselkorn

An approach to modeling the material removal rate (MRR) during rotary ultrasonic machining (RUM) of ceramics is proposed and applied to predicting the MRR for the case of magnesia stabilized zirconia. The model, a first attempt at predicting the MRR in RUM, is based on the assumption that brittle fracture is the primary mechanism of material removal. To justify this assumption, a model parameter (which models the ratio of the fractured volume to the indented volume of a single diamond particle) is shown to be invariant for most machining conditions. The model is mechanistic in the sense that this parameter can be observed experimentally from a few experiments for a particular material and then used in prediction of MRR over a wide range of process parameters. This is demonstrated for magnesia stabilized zirconia, where very good predictions are obtained using an estimate of this single parameter. On the basis of this model, relations between the material removal rate and the controllable machining parameters are deduced. These relationships agree well with the trends observed by experimental observations made by other investigators.


Author(s):  
Andrew W. McFarland ◽  
Jonathan S. Colton ◽  
Daniel Cox ◽  
Steven Y. Liang

Mechanical micro machining is an emerging technology with many potential benefits and equally great challenges. The push to develop processes and tools capable of micro scale fabrication is a result of the widespread drive to reduce part and feature size. One important factor that contributes to the ability to machine at the microscale level is the overall size of the machine tool due to the effects of thermal, static, and dynamic stabilities. This paper explores the technical feasibility of miniaturized machine tools capable of fabricating features and parts on the micro scale in terms of depth of cut and part form accuracy. It develops a machine tool and examines its capabilities through benchmarking tests and the making of precision dies for the injection molding of microcantilever parts. The design and configuration of a miniaturized vertical machining center of overall dimension less than 300 mm on a side is presented and the component specifications discussed. The six axis machine has linear positioning resolution of 4 nm by 10 nm by 10 nm, with accuracy on the order of 0.3 μm, in the height, feed, and cross feed directions. The work volume as defined by the ranges of axes travel are 4 mm by 25 mm by 25 mm in the height, feed, and cross feed and 20 degrees in the rotational space. To quantify the performance capability of the miniaturized machine tool as a system, a series of evaluation tests were implemented based on linear and arch trajectories over a range of feed speed and depth of cut conditions. Test results suggest that micro level form accuracy and sub-micron level finish are generally achievable for parts with moderate curvature and gradient in the geometry under selected machining parameters and conditions. An injection mold was made of steel with this machine and plastic microcantilevers fabricated. Plastic microcantilevers are appropriate for sensing applications such as surface probe microscopy. The microcantilevers, made from polystyrene, were 464 to 755 μm long, 130 μm wide and only 6–9 μm thick. They showed very good uniformity, reproducibility, and appropriate mechanical response for use as sensors in surface force microscopy.


2013 ◽  
Vol 59 (Special Issue) ◽  
pp. S42-S48
Author(s):  
R. Drlička ◽  
J. Žarnovský ◽  
R. Mikuš ◽  
I. Kováč ◽  
M. Korenko

For the renovation and/or improvement of the surface properties of machine elements, hard facing is often used. Hard structures obtained in layers or by heat treatment achieve a hardness of up to 68 hardness (HRC) or even more. The grinding of these surfaces demands the use of processing fluids and causes sometimes changes in the surface layers structure. Hard turning can replace grinding when certain requirements are fulfilled, particularly tough machining system. Hard deposits of two weld-on materials on a sample of steel grade S235JRG1 have been turned using cemented carbide inserts with a TiAlN coating of PVD type. The surface roughness measurements along with the observation of insert wear have been conducted to find proper machining parameters and conditions for this application. Cutting inserts manufacturer guidelines for special application could be insufficient or even not provided. Besides that, it is necessary in the experiments to take into account and examine the cutting ceramics and cubic boron nitride (CBN)/polycrystalline cubic boron nitride (PCBN).


2017 ◽  
Vol 41 (1) ◽  
pp. 129-141 ◽  
Author(s):  
K.M. Kumar ◽  
P. Hariharan

This work compares the effect of cubic boron nitride (CBN) and multilayer (TiCN+Al2O3+TiN) coated tungsten carbide (WC) tools during the turning of spheroidal graphite (SG) nodular iron. Nodular irons have more ductility which is required in mechanical components that demand high fatigue resistance like crankshafts, cam shafts, bearing caps and clutch housings. The impact of various process parameters like the depth of cut, cutting speed and feed on the surface roughness (Ra) of SG iron is studied and optimized using the response surface model. The chip morphology is also discussed for evaluation of the quality of the turned surface. The experimental outcomes reveal that the WC tool offers a high surface finish at the optimal combination of the cutting speed at 102 meter/minute, feed at 0.051 millimeter/revolution and depth of cut at 0.5 millimeter and that, for the CBN insert, at 245 meter/minute of cutting speed, 0.051 millimeter/revolution of feed and 0.75 millimeter of depth of cut.


2007 ◽  
Vol 359-360 ◽  
pp. 425-430 ◽  
Author(s):  
Wei Min Zeng ◽  
Zhi Chao Li ◽  
Xi Peng Xu ◽  
Zhi Jian Pei ◽  
Ju Dong Liu ◽  
...  

Rotary ultrasonic machining (RUM) is considered as an effective machining method, which has been utilized to machine hard and brittle materials such as advanced ceramics. In order to improve the hole wall surface quality during RUM, it is important to wash away swarf in the gap between the tool and the workpiece as fast as possible. In this paper, a new machine process – intermittent rotary ultrasonic machining (IRUM) – is introduced for the first time. The cutting force, surface roughness and coolant flow rate in conventional rotary ultrasonic machining (CRUM) process and IRUM process are compared. It is found that compared with CRUM, the output coolant flow rate could be increased significantly by using the IRUM method. It is also found that the surface roughness of workpiece can be improved significantly in IRUM.


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