Abstract: In turning hardened steel, polycrystalline cubic boron
nitride (cBN) compacts are widely used, due to their higher hardness
and higher thermal conductivity. However, in milling hardened steel,
fracture of cBN cutting tools readily occurs because they have poor
fracture toughness. Therefore, coated cemented carbide tools, which
have good fracture toughness and wear resistance, are generally
widely used. In this study, hardened steel (ASTM D2, JIS SKD11,
60HRC) was milled with three physical vapor deposition
(PVD)-coated cemented carbide end mill cutters in order to determine
effective tool materials for cutting hardened steel at high cutting
speeds. The coating films used were (Ti,W)N/(Ti,W,Si)N and
(Ti,W)N/(Ti,W,Si,Al)N coating films. (Ti,W,Si,Al)N is a new type of
coating film. The inner layer of the (Ti,W)N/(Ti,W,Si)N and
(Ti,W)N/(Ti,W,Si,Al)N coating system is (Ti,W)N coating film, and
the outer layer is (Ti,W,Si)N and (Ti,W,Si,Al)N coating films,
respectively. Furthermore, commercial (Ti,Al)N-based coating film
was also used. The following results were obtained: (1) In milling
hardened steel at a cutting speed of 3.33 m/s, the tool wear width of the
(Ti,W)N/(Ti,W,Si,Al)N-coated tool was smaller than that of the
(Ti,W)N/(Ti,W,Si)N-coated tool. And, compared with the commercial
(Ti,Al)N, the tool wear width of the (Ti,W)N/(Ti,W,Si,Al)N-coated
tool was smaller than that of the (Ti,Al)N-coated tool. (2) The tool
wear of the (Ti,W)N/(Ti,W,Si,Al)N-coated tool increased with an
increase in cutting speed. (3) The (Ti,W)N/(Ti,W,Si,Al)N-coated
cemented carbide was an effective tool material for high-speed cutting
below a cutting speed of 3.33 m/s.
Abstract: In this paper by measuring the cutting forces the effect
of the tool shape and qualifications (sharp and worn cutting tools of
both vee and knife edge profile) and cutting conditions (depth of cut
and cutting speed) in the turning operation on the tool deflection and
cutting force is investigated. The workpiece material was mild steel
and the cutting tool was made of high speed steel. Cutting forces
were measured by a dynamometer (type P.E.I. serial No 154). The
dynamometer essentially consisted of a cantilever structure which
held the cutting tool. Deflection of the cantilever was measured by an
L.V.D.T (Mercer 122) deflection indicator. No cutting fluid was used
during the turning operations. A modern CNC lathe machine (Okuma
LH35-N) was used for the tests. It was noted that worn vee profile
tools tended to produce a greater increase in the vertical force
component than the axial component, whereas knife tools tended to
show a more pronounced increase in the axial component.
Abstract: The stochastic nature of tool life using conventional discrete-wear data from experimental tests usually exists due to many individual and interacting parameters. It is a common practice in batch production to continually use the same tool to machine different parts, using disparate machining parameters. In such an environment, the optimal points at which tools have to be changed, while achieving minimum production cost and maximum production rate within the surface roughness specifications, have not been adequately studied. In the current study, two relevant aspects are investigated using coated and uncoated inserts in turning operations: (i) the accuracy of using machinability information, from fixed parameters testing procedures, when variable parameters situations are emerged, and (ii) the credibility of tool life machinability data from prior discrete testing procedures in a non-stop machining. A novel technique is proposed and verified to normalize the conventional fixed parameters machinability data to suit the cases when parameters have to be changed for the same tool. Also, an experimental investigation has been established to evaluate the error in the tool life assessment when machinability from discrete testing procedures is employed in uninterrupted practical machining.
Abstract: The energy consumption of home femto base stations
(BSs) can be reduced, by turning off the Wi-Fi radio interface when
there is no mobile station (MS) under the coverage of the BSs or
MSs do not transmit or receive data packet for long time, especially
in late night. In the energy-efficient home femto BSs, if MSs have
any data packet to transmit and the Wi-Fi radio interface in off
state, MSs wake up the Wi-Fi radio interface of home femto BSs
by using additional low power radio interface. In this paper, the
performance of the energy-efficient home femto BSs from the aspect
of energy consumption and cumulative average delay, and show the
effect of various parameters on energy consumption and cumulative
average delay. From the results, the tradeoff relationship between
energy consumption and cumulative average delay is shown and thus,
appropriate operation should be needed to balance the tradeoff.
Abstract: In this paper we propose a novel approach for
searching eCommerce products using a mobile phone, illustrated by a
prototype eCoMobile. This approach aims to globalize the mobile
search by integrating the concept of user multilinguism into it. To
show that, we particularly deal with English and Arabic languages.
Indeed the mobile user can formulate his query on a commercial
product in either language (English/Arabic). The description of his
information need on commercial products relies on the ontology that
represents the conceptualization of the product catalogue knowledge
domain defined in both English and Arabic languages. A query
expressed on a mobile device client defines the concept that
corresponds to the name of the product followed by a set of pairs
(property, value) specifying the characteristics of the product. Once a
query is submitted it is then communicated to the server side which
analyses it and in its turn performs an http request to an eCommerce
application server (like Amazon). This latter responds by returning
an XML file representing a set of elements where each element
defines an item of the searched product with its specific
characteristics. The XML file is analyzed on the server side and then
items are displayed on the mobile device client along with its
relevant characteristics in the chosen language.