The purpose of this paper is to present the application of a procedure for the quality control of stainless steel tubes produced for automotive exhaust systems from a…
The purpose of this paper is to present the application of a procedure for the quality control of stainless steel tubes produced for automotive exhaust systems from a leading company in the steel sector, based on the Delphi method in accordance with the ISO/TS 16949:2009 and the ISO 9000:2008. Using Delphi methodology, it was possible to identify the main problems in the production lines object of the study, the main defects and their causes. Statistical methods were used to monitor process compliance and capacity. The panel of experts involved in Delphi method was able to identify causes of non‐compliance and suggest corrective actions.
The quality procedure implemented involves the application of the Delphi method and the ISO/TS 16949:2009 standard in conjunction with ISO 9000:2008 to the production line of welded tubes for exhaust systems. The statistical methods used to monitor the process were mainly control charts. Capability index, Cp and Cpk, were used to measure the process attitude to produce compliant outputs. Dimensional data were acquired by non‐destructive testing on diameters and X‐R charts were used to graphically represent the process state of control. Destructive tests were performed to monitor the welding quality and P‐chart were used to assess the proportion of nonconforming units.
In this work, a procedure was developed in order to characterize the production process of TXM tubes realized in the line 31 of the leader company plant. The use of Delphi methodology, in order to incorporate experts opinions in the quality control of stainless steel tubes, was one of the main points of this work. The panel of experts worked together to identify process issues, define their causes and propose corrective actions. The paper provides an overview about the quality approach of one of the world's largest companies in the production of steel and shows also how the statistical tools are used in order to manage process behavior.
The value of this paper is to illustrate an innovative approach to a real life quality problem; it demonstrates how the application of qualitative and quantitative quality instruments in accordance with technical specification can help in increasing and maintaining product compliance and in optimizing the management of resources.
ENGINE testing has never been a subject to take for granted. Even thirty years ago, when test facilities were far from the sophisticated entities they are today, aerospace…
ENGINE testing has never been a subject to take for granted. Even thirty years ago, when test facilities were far from the sophisticated entities they are today, aerospace engineers were well aware of the necessity of regular testing. Then, as now, it not only ensured air worthiness but it also extended the flying life of the engine.
TO stand above the new Rolls‐Royce Sinfin test plant provokes many assorted thoughts. Here is tradition—the tradition of the British engineer—set forth in acres of intricate machinery. Here is enormous power. And here is the signpost to the future. This vast undertaking shows how great and important are the changes taking place in our time.
THE problem of silencing test houses for turbo‐jet engines is, acoustically, analogous to that for test beds for piston engines1 and 2 but is more complicated owing to the…
THE problem of silencing test houses for turbo‐jet engines is, acoustically, analogous to that for test beds for piston engines1 and 2 but is more complicated owing to the working conditions of turbo‐jet engines.
ACCORDING to historical records the earliest known drawings for an aerial machine that can be classified under the heading of helicopter were made in the fifteenth century…
ACCORDING to historical records the earliest known drawings for an aerial machine that can be classified under the heading of helicopter were made in the fifteenth century by the world renowned Italian scientist and artist Leonardo da Vinci (1452–1519). Probably the Chinese had been making their helicopter toy for some considerable time before da Vinci commenced his experiments. This toy consisted of two feathers, joined together by means of a cork or soft wood boss, to form a crude type of propeller which was pushed up a threaded stick so that upon leaving the stick the propeller rotated at high speed and continued to screw itself up in the air. When the speed of rotation decreased the propeller slowly windmilled down to the ground. A similar toy is still being sold today.
An aircraft of generally circular configuration in plan and constructed for vertical, horizontal and hovering flight, comprises; a saucer‐shaped fuselage having a cabin spaced between the periphery and centre thereof and a rigid ring‐shaped cambered aerofoil providing the peripheral portion of the fuselage and interrupted by the cabin. A compressor substantially enclosed by the fuselage at the centre comprises a pair of flared and vertically spaced plates and a plurality of generally vertical and radially extending vanes between the plates, the upper ends of the plates providing a plurality of circumferentially spaced air intake openings and the lower ends a plurality of circumferentially spaced air discharge openings whereby the path of air flow is first vertical and then radial. A stator assembly entirely surrounds the compressor and is also enclosed by the fuselage. The stator assembly comprises a pair of vertically spaced plates mounted closely adjacent to the lower ends of the compressor plates to receive air from the compressor discharge openings and direct that air over the upper surface only of the aerofoil. The stator assembly further includes a plurality of arcuately swept vanes mounted for horizontally swingable movement by the stator plates and being of a length such that when a pair of the vanes are pivoted to a sufficient degree the ends thereof overlap and the compressed air flow over a particular portion of the aerofoil is closed off, and means for rotating the compressor to take air from the atmosphere into the intake openings and between the compressor plates first in a generally vertical direction and then radially in compressed condition through the discharge openings and through the stator assembly over the upper surface of the aerofoil to cause the aircraft to ascend and hover, whereupon when horizontal flight is desired the stator vanes are adjusted to direct the air over only particular portions of the upper surface of the aerofoil.
The British Food Journal is in no way concerned with politics, and as it would appear that the propositions put forward by Mr. CHAMBERLAIN are commonly regarded as constituting matter for political controversy instead of being looked upon as subjects for serious investigation and discussion entirely outside the field of politics, it would be an undesirable course and one likely to be misunderstood and, no doubt, misrepresented, were we to refer to the great question which is now before the country without plainly indicating at the outset that we have no intention of supporting or opposing any political party or any section of politicians. We believe Mr. CHAMBERLAIN'S suggestion that the subjects which he has brought forward should be discussed on a higher plane than on the muddy plane of party politics was a reasonable and proper suggestion which all men of sense who are not blinded by political bias should applaud and endeavour to adopt. We do not mean to say that problems of so complicated a character are capable of being accurately solved, in the present state of knowledge, by scientific methods other than actual experiment. They certainly cannot be solved by abstract discussions of a pseudo‐scientific character. The factors which enter into the problems of political economy are so numerous, so complex, and so little understood, that to endeavour to argue even on the basis of what are alleged by political economists to be well‐ascertained facts in the so‐called “dismal science” is to lay oneself open to the charge of theorising from insufficient data. HERBERT SPENCER has lucidly demonstrated the universality of this scientific crime. On comparatively simple subjects, in regard to which a man has no special knowledge, he will, if possessed of the quality known as common sense, generally decline to deliver oracular opinions; but, let a subject be sufficiently complex and let the data relating to it be few, obscure, and uncertain, then decisive opinions will be delivered by all and sundry,—and the more profound the ignorance the more decisive will be the expression of opinion.
A jet propulsion engine comprises a downstream element separate from but normally forming a continuation of the housing defining a jet pipe, so that the upstream end of the element is spaced outwardly of and overlaps the downstream end of the pipe to form therewith an annular space, and blocking means normally housed in the said space, wherein the downstream element is movable axially to open a gap between itself and the housing and to permit the blocking means to be moved to a position directing the jet stream through the gap. The apparatus is shown in jet deflecting disposition, in which the silencing nozzle 14 has been moved downstream, so that the nozzle wall 10 is separated from a skirt 91 on the jet pipe, and a nozzle fairing skirt 15 is separated from the housing 9. The blocking means comprises clam shell elements 2 pivoted on a transverse axis 20 and noted at 21 to fit on to a tail cone 80. To revert to the normal disposition, the shell elements 2 are swung by actuators 24 to lie outside the skirt 91, and the nozzle 14 is retracted by actuator 31, being slidably mounted by beams 3 and guides 30 (one shown). The shells then lie between skirts 15 and 91. The actuators 24 and 31 or their controls may be interconnected.
A DIAGRAMMATIC layout of the main fuel system can be seen in fig. 14. Fuel from the tank is fed through a low pressure filter to the main fuel pump. This pushes the fuel…
A DIAGRAMMATIC layout of the main fuel system can be seen in fig. 14. Fuel from the tank is fed through a low pressure filter to the main fuel pump. This pushes the fuel through to the governor and throttle valve (integral with the governor). From the throttle valve the fuel passes through a non‐return valve into the burner ring. This non‐return valve prevents fuel leakage when the engine is shut down.