HRR Machining involves the use of extremely rigif, high-power, high-precision machines, such as roll turning lathes, to achieve material removal rates far beyond the capacity of conventional machine tools.
(Black J. T., Introduction to Machining Processes)
High Removal Rate Machining (new-better) (manufacturing process)
A high removal rate corresponds to a high normal force and the tool-life is
correspondingly reduced by tool wear. A high wear rate of the abrasive tool
reduces grinding productivity.
To summarize, conditioning is carried out for one or more of the
following reasons:
• Loss of wheel shape accuracy due to wear or wheel
loading.
• High energy consumption and consequent temperaturerise
during the grinding process.
• Loss of workpiece surface quality.
• Low accuracy of finished workpieces.
• Reduced productivity.
The purpose of conditioning a tool is to restore productivity to its
initial value. A conditioning process aims to assure a clean abrasive surface
of appropriate microtopography for subsequent abrasive machining operations.
On average, only 10% of the active volume of the wheel is worn away
by grinding. The remaining 90% is removed by wheel conditioning operations.
Tool redress life, for repeated batch production, can be experimentally
determined on the basis of systematic commissioning tests. Determination
of the tool redress life is part of a process of optimizing the dressing
and grinding conditions for a new product. Determination of tool redress
life constitutes an aspect of ongoing process improvement in modern
industrial practice.
(TRIBOLOGY OF ABRASIVE MACHINING PROCESSES, Ioan D. Marinescu, W. Brian Rowe, Boris Dimitrov, Ichiro Inasaki, 2004, page: 460,461)
2) Gnome Rotary Engine (old)
To cope with this limitation an engine intended to enhance the cooling performance by rotating the engine together with the propeller was developed . Concevied form this innovative idea was the 1909 Gnome engine.
In the Gnome engine, the piston and clinders rotate at a speed of about 1150 to 1250 rpm. The cranksahft is hollow , through which gasoline and air are supplied , but this engine does not have carburetor. The gasoline , which was gravity-fed , flowed through the inside of the crankshaft , entered the combustion chamber through the intake valve in the psiton crown.
(The romance of engines ; Takashi Suzuki , pg . 210-212 , 1997)
Gnome Rotary Engine (new-better) (engine)
The rotary aero engine sprang into prominence with the introduction of the
50 hp Gnome in 1908. and in particular. with Henri Farman's adoption of
this model for the famous 1909 Rheims meeting. ‘the first great aviation
meeting of history‘. where he carried off the Grand Prix for the greatest
non-stop distance llown (180 km) and set up a world record for endurance.
The rotary quickly became the aeronautical powerplant par excellence and
dominated records and results in the remaining years of peace.
During the First World War. the rotary was initially the_most important
type of aircraft power unit on the Allied side. although towards the end of
the struggle the relative contribution began to decline as competitive
stationary engines entered service. However. developed examples of the
rotary stayed in front-line use up to the end of hostilities. By 1919. virtually
all production and design work on rotaries had stopped. and thereafter. few
references are to be found to them in aeronautical and engineeringjoumals.
The rotary is a special form of air-cooled radial engine. in which a
number of cylinders are arranged like the spokes of a wheel. around the
crankshaft. For an aero engine. the radial arrangement has several advan-
tages. Grouping the cylinders in one plane around a single crank gives a
very short engine. with a considerable weight saving over the in-line type. in
which every cylinder requires its own crank ‘throw’. Furthermore. the cylin-
drical crankcase of the radial is an elficient ‘drum’ type of structure which
resists engine working stresses by radial tension loads. and thus can be
built light. In the rotary version. for better cooling. the modeol operation is
reversed from that of the normal radial. so that the crankshaft remains
stationary (and supports the assembly). while the cylinders. and the body of
the engine rotate around it. Perhaps this counter-intuitive (some would say
perverse) arrangement explains the continued fascination the species holds
over aviation historians and enthusiasts. (A French author writing in 1910
commented: ‘their bizarre appearance. the originality of their parts. draws
and retains the attention°.) In addition. the engines themselves are superbly
constructed. typically of fully machined fine-section nickel-steel
components. made and fitted to the highest standards of Edwardian
engineering. Given this abiding interest. it seems remarkable that there
appears to have been no convincing attempt to explain the most curious
and absorbing features of the ‘rotary phenomenon’ - the dramatic and
immediate superiority over all competing types at its inception. and the
equally abrupt disappearance from the world of aviation in 1918.
(The rotary aero engine,
Andrew Nahum, 1999, page: 7,8)
3) Product and manufacturing information (PMI) (old-better)
Product and manufacturing information (PMI) is used in 3D CAD and/or collaborative product development systems to convey information about the design of a product’s components for manufacturing. More specifically, PMI conveys information such as geometric dimensioning and tolerancing (GD&T), 3D annotation (text), surface finish and material specifications. Product and manufacturing information Enhances and shortens the design cycle by enabling product teams to incorporate product and process information during the design phase, thereby facilitating beter communications, fewer errors, streamlined design/manufacturing processes and faster change management. PMI accelerates decision making by enabling product teams to remove drawings from the supplier communication chain and replacing that information with persistent, associated 3D product data that can be deployed across multiple lifecycle processes. (Product and Manufacturing Information (PMI) management,NX Siemens,2011)
Product and manufacturing information (PMI) (new) (manufacturing information)
To support automatic dimensional metrology plan generation using the simplest
case. a product consists of a single monolithic part can be selected as an example.
Figure 7.1 depicts some key functions that occur during the early stages of the part
definition activity. The part must be decomposed into geometric features.
Dimensions and tolerances must then be assigned to a geometric feature, or set of
features. Datum features must be defined in such a way that they are appropriate
both for manufacturing the part and for inspecting it. It is not uncommon that
datum features are not the same for manufacturing and for inspecting purposes.
Surface texture infonnation must be included in the model. along with relevant
infonnation about the orientation or lay of the surface texture to be measured. Such
information is typically referred to as Product Manufacturing Information (PMI).
Accurately extracting PMI information requires interaction with the manufacturing
process plan, which in tum defines the process used to create the surface that is to
be measured. Therefore a process definition that defines the manufacturing and
measuring process must be interconnected with elements within the product def-
inition. Furthermore, the process requires resources (sensors, fixtures, machines).
and therefore a resource definition that supports the process definition must be
represented [l]. This ideal situation, however, does not exist in today’s industry.
Currently PM! information is available in proprietary software to only a limited
extent. There is no CAD product implementation of PMI information using non-
proprietary standards. STEP AP 203 edition 2 consists of PMI information but has
not yet been fully adopted by CAD vendors. Also, once AP 203 edition 2 is
successfully implemented by CAD vendors, the implementation needs to be val-
idated by standards organizations so as to ensure the accuracy.
(Information Modeling for Interoperable Dimensional Metrology, Yaoyao (Fiona) Zhao, Robert Brown, Thomas R. Kramer, Xun Xu, 2011, page: 256)
4) Electroerosion Dissolution Machining
(07 Nisan 2011 10:10) (old)
Novel methods of machining hard metals, which
are difficult to cut by conventional methods, continue to attract attention.
Electrochemical machining and electrodischarge machining have proven to be very
useful. However, drawbacks such as the expense of tooling for machining
large cavities, the high cost of machining systems, low rates of metal
removal, and the presence of a recast layer, which often has to be removed in
EDM, have hindered wider acceptance of these techniques. EEDM (also called ECDM
or ECAM) is a new development, which combines features of both ECD and EDE. It
utilizes electrical discharges in electrolytes for material removal. Such a
combination allows high metal removal rates to be achieved. EEDM has found a
wide range of applications in the field of wire cutting, hole drilling, and
finishing of dies and molds.
(Advanced Machining Processes, Hassan El-Hofy;
Page:204)
Electroerosion Dissolution Machining (new-better) (manufacturing method)
The combination of electrochemical machining
(ECM) and electrodischarge machining (EDM) in a
single operation can yield higher removal rates and
superior surface integrity than those obtainable by the
separate processes. Such advantages have been investigated
by many researchers. In the early 1980s Kubota
[1] studied hole-drilling, terming the process electrochemical
discharge machining (ECDM). Based on the
evidence that high removal rates occur due to discharges
of relatively long time duration across the
interelectrode gap, McGeough and Drake [2] investigated
long hole-drilling by electrochemical arc machining
(ECAM). Detailed analysis of the underlying
mechanisms and the contribution of the distinct machining
phases prompted Khayry et al. [3] to describe
the combined process as electro-erosion dissolution machining
(EEDM). Other researchers [4,5] report the
electrochemical spark machining of composite
materials.
Irrespective of the terminology, unified processes that
combine ECM and EDM generally rely on the application
of a pulsed voltage across the anodic workpiece
and cathodic tool, the gap between which is filled with
a flowing electrolyte solution. In addition to holedrilling,
the process has found applications in die-sinking,
turning, surface finishing, and for wire cutting.
In preliminary investigations of EEDM applied to
wire-cutting (WEED), a relatively thick wire, of 1.5 mm
diameter, was vibrated at a fixed amplitude and phase
angle in relation to full-wave rectified (100 Hz) voltage
pulses, in the vicinity of a workpiece. Electrolyte flushing
coaxial to the wire was employed [6]. Later developments
of the process relied on much thinner wires, and
machining was deduced to occur due to major thermal
erosive action, assisted by a minor dissolution phase. In
addition to the high removal rates, WEED offers simultaneous
removal of the re-cast layer caused by the
discharges, as a consequence of ECM action at the
sides of the wire-electrode. In die- and mould-manufacture,
which is the main application of WEED, such a
finishing action reduces the time and costs involved
compared to established wire-EDM [7] (the latter process
is rapidly becoming integrated within computercontrolled
manufacturing systems).
If the new WEED process is also to be accepted fully
in this way, evaluation through an intelligent knowledge-based system that provides product designers and
manufacturing engineers with a reliable guide to its
efficiency as a production tool is desirable. Such a
procedure for WEED forms the basis of this paper.
(Journal of Materials Processing Technology, M Sadegh Amalnik, H.A El-Hofy, J.A McGeough, 1998, page: 155,156)
5) Stapling (old) In stampling, preformed
U-shaped staples are punched through the two parts to be attached.The staples
are supplied in convenient strips.The individual staples are lightly stuck
together to form the strip, but they can be seperated by stapling tool for
driving.The staples come with various point styles to facilitate their entry
into the work.Staples are usually applied by means of portable pneumatic guns,
into which strips containing several hundred staples can be loaded.Applications
of industrial stapling include ;furniture and upholstery , assembly of car
seats, and various light-gage sheetmetal and plastic assembly
jobs.
(Fundamentals of modern manufacturing,materials,processes and systems,3rd edition, Mikell P.Groover, p.775) 00.45
(Fundamentals of modern manufacturing,materials,processes and systems,3rd edition, Mikell P.Groover, p.775) 00.45
Stapling (new-better) (fastening method)
The stitching or stapling of thin-gauge sheet metals with wires was, by the late
1950's, developed to the point that machines were available capable of driving
steel wire through ~/16-inch (1.5-mm) sheet metal at speeds up to nearly 300
stitches per minute. The processes could be used to fasten metal to metal or
metal with a softer material, including rubber, plastics, leather, wood veneers,
plywood, fiberboard, cork sheets, or fire-resistant materials, including, at the
time, asbestos.
During stitching, or what really much more closely resembles stapling, the
wire is fed through gear-driven feed rolls to a device that grips and holds it in
position until a cutoff die cuts it to a predetermined length. The cut wire is carfled
by a mandrel to forming dies that bend it to an inverted U shape. These Ushaped
staples are then driven downward through the sheets to be attached
using a ram. The legs of the staple that pierce and project through the material
are formed against a clinching die while the top of the staple is pressed tightly
against the material to resist the forming force and develop a slight squeezing
force through the layers of materials.
Figure 7.18 schematically illustrates various types of stitches or staples, as
well as the recommendations for parallel and diagonal stitch placement.
Normally, 0.048-inch (1.2 mm) diameter steel wire, cold-drawn to a tensile
strength of from 220,000 to 330,000 psi (1,500-2,300 MPa), was used. The
lower strength wire was capable of penetrating a single thickness of 0.020-inch
(0.5 mm) soft steel, while the highest strength wire was capable of penetrating
two sheets of 0.048-inch (1.2 mm) thick cold-rolled AISI 1010 steel.
Metal stitching or stapling is a good replacement for riveting or screwing
thin sheet metal to other materials when large areas are involved, and out-ofplane
loading would put adhesives under an undesirable peeling force. When
attaching softer materials to metal, the stitches or staples should be pushed
through from the steel side and clinched on the softer material side.
As important as sheet-gauge material is to the fabrication of components,
products, assemblies, and structures from metal, other product forms are also
extensively used, and usually for higher-load situations. The major other product
forms of metals are (1) castings, (2) extrusions, (3) forgings, and (4)
machined parts. For net-shaped castings, extrusions, and net-shaped forgings,
integral attachment features can be incorporated into geometry of the part to
allow mechanical attachment between parts. For machined parts, such features
are machined into the part.
(Integral Mechanical Attachment-- A Resurgence of the Oldest Method of Joinig, Robert W. Messler Jr., 2006, page: 200,201)
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