1st Week 030070154 Ebubekir Çantı

1) Hot İsostatic Pressing  (HIP) (Manufacturing)


HIP involves  isostatic  compaction  of  powders  (and other  materials)  at  an  elevated  temperature.  A water-cooled pressure vessel with an internal high-temperature  furnace  is  employed.  Pressures  reach about  45,000  lbf/in2 (310  MPa)  and  temperatures about  3600°F (2000°C). Argon, nitrogen,  or  helium gas is pressurized and acts against the surfaces of  the  workpiece  through  a  hemetically  sealed glass  or metal  encapsulation. Because  of  the  high temperatures  involved,  sheet  metal,  if  used  for encapsulation, must be  refractory.  Glass envelopes soften  at  the  temperatures  involved  but  still  transmit  the  pressure to  the  ceramic  material. Pressure and  temperature  are  closely  controlled.  Electrical resistance  heating  is usually  used.  The  method  is advantageous for producing  more  complex  shapes of  parts  than  by  regular hot  pressing.  Improved, more-uniform  compaction  for  critical  parts  is  an important  advantage.  The  process  is  applicable  to powder metals and cermets as well as ceramic powders and is used to remove voids in castings for critical parts  such as turbine blades, to compact powder metal parts to almost 100 percent density of the metal involved  and  to  bond  dissimilar materials  together.

HandBook of Manufacturing Processes, James G. Bralla p.287


Previous Description

Hot Isostatic Press (HIP): The container is made of a high-melting-point sheet metal, and the pressurizing is high-temperature inert gas or a vitreous (glasslike) fluid. Common condition for HIP are pressure as high as 100 MPa (15 ksi) - although it can be three times as high - and at a temperature 1200 ⁰C (2200 ⁰F). The main advantage of HIP is its ability to produce having almost %100 density. Consequently, it has gained wide acceptance in making high-quality parts.

The HIP process is used mainly in making superalloy components for the aircraft and aerospace industries and in military, medical and chemical applications. It also is used to close internal porosity, to improve properties in superalloy and titanium-alloy castings for the aerospace industry, and as a final densification step for tungsten-carbide cutting tools and P/M tool steels.

(Kalpakjian S., Schmid S.R.,Manufacturing engineering and technology, 5th Edition, p. 494,495)

2) Vulcanization(Manufacturing)

The term vulcanization is derived from "Vulcan," the Roman fire god, its connection with regard to rubber being therefore the heat which causes rubber when mixed with sulphur, to assume entirely different physical and chemical properties. There are two general methods of vulcanization, namely, what is known as the " cold cure " and the " hot cure vulcanization." The former is effected by the use of a sulphur mono--chloride solution, which acts upon the rubber, and as it is a surface action, it may be employed only with very thin articles. This method is also allowed to take place by placing the articles to be vulcanized in the vapors of sulphur monochloride. The credit for this process belongs to Parkes, who, in 1S46, dipped thin strips of caoutchouc, for different lengths of time, in to a solution of 100 parts of carbon disulphide and 2.5 parts of sulphur monochloride. After dipping these strips, he quickly dried them at 78 deg. F. and then washed them in warm water. The process has been modified somewhat since his day but the essential features were known to him.

The credit for the " hot vulcaniza-tion " should be divided between Hancock and Goodyear, who independently discovered that rubber, when heated in contact with sulphur, changes its properties very materially. Thej' arrived at this conclusion, however, by slightly different means. Hancock in 1843 patented a process for vulcanization whereby he subjected sheets of rubber to the action of molten sulphur heated to a temperature of 284 deg. to 302 deg. F., when the rubber took up 10 to 15 percent of sulphur. Of course, these sheets had a great tendency to bloom, so he washed them with a solution of soda. At the same time Hancock was trying these experiments, Good-year was working along the same lines, only he was mixing the sulphur into the rubber, until he had a homo-geneous mixture which he subjected to a high temperature. Of course, the two results were similar, but Good-year's method being, in many ways, the easiest to control, is the one which has survived. Gerard found that it was possible to effect vulcanization by subjecting the rubber for three hours, under a pressure of four atmospheres in a solution of calcium pentasulphide, to a temperature of 265 deg. F. The articles are then removed and washed with warm water. They are well cured and will possess a velvety appearance. The length of time they must remain in such a bath, of course, is determined by the thickness of the articles to be vulcanized.

Rubber Manufacture- H. E. SIMMONS-pg 98

Previous Description

Vulcanization

Vulcanization is a process generally applied to rubbery or elastomeric materials. These materials forcibly retract to their approximately original shape after a rather large mechanically imposed deformation. Vulcanization can be defined as a process which increases the retractile forces and reduces the amount of permanent deformation remaining after removal of the deforming force. Thus vulcanization increases elasticity while it decreases plasticity. It is generally accomplished by the formation of a crosslinked molecular network ( fig.1.)

According to the theory of rubber elasticity, the retractile force to resist a deformation isproportional to the number of network supporting polymer chains per unit volume of elastomer. A supporting polymer chain is a linear polymer molecular segment between network junctures. An increase in the number of junctures or crosslinks gives an increase in the number of supporting chains. In an unvulcanized linear high polymer (above its melting point), only molecular chain entanglements constitute junctures.

Vulcanization, thus, is a process of chemically producing network junctures by the insertion of crosslinks between polymer chains. A crosslink may be a group sulfur atoms in a short chain, a single sulfur atom, a carbon to carbon bond, a polyvalent organic radical, an ionic cluster, or a polyvalent metal ion. The process is usually carried out by heating the rubber, mixed with vulcanizing agents, in a mold under pressure.

(Mark, J., Erman, B., Eirich, F.R., Science and technology of rubber, 3^rd Edition, pg.322)

3) Computer Aided Manufacturing(Manufacturing)


Computer Aided Manufacturing(CAM) is a widely used term in industrial literature, and it has various meanings. Here it is defined simply as those types of programmable automation which are used primarily on the factory floor to help produce products. The following sections provide functional descriptions of four CAM tools; robots, numerically machine tools, flexible manufacturing systems and automated materials handling systems.


Computerized manufacturing automation : employment, education, and the workplace. p.48


Previous Description


Computer-aided manufacturing
Computer-aided manufacturing (CAM) involves the use of computers to assist in all phases of manufacturing a product. Because of the joint benefits, computer-aided design and computer-aided manufacturing often are combined into CAD/CAM systems. This combination allows the transfer of information from the design stage into the stage of planning for manufacture without the need to reenter the data on part geometry manually. The database devoloped during CAD is stored and processed further by CAM nto the necessary data and instructions for operating and controlling production machinery, material-handling equipment, and automated testing and inspection for product quality. CAD/CAM systems also are capable of coding and classifying parts into groups that have similar shapes using alphanumeric coding.

(Kalpakjian S., Schmid S.R.,Manufacturing engineering and technology, 5th Edition, p 1203)




4) Composite(Material)


Composite materials are multiphase materials obtained through the artificial com-bination of different materials in order to attain properties that the individual com-ponents by themselves cannot attain. They are not multiphase materials in which the different phases are formed naturally by reactions, phase transformations, or other phenomena. An example is carbon fiber reinforced polymer. Composite materials should be distinguished from alloys, which can comprise two more com-ponents but are formed naturally through processes such as casting. Composite materials can be tailored for various properties by appropriately choosing their components, their proportions, their distributions, their morphologies, their de-grees of crystallinity, their crystallographic textures, as well as the structure and composition of the interface between components. Due to this strong tailorability, composite materials can be designed to satisfy the needs of technologies relat-ing to the aerospace, automobile, electronics, construction, energy, biomedical and other industries. As a result, composite materials constitute most commercial engineering materials.


Deborah D. L. Chung, Composite Materials Science and Applications, pg 1.




Previous Description

Composite 02.04.2011 23:47

Composites do not really constitute a separate category of materials; they are mixtures of the other three types. A composite is a material consisting of two or more phases that are processed separately and then bonded together to achieve properties superior to those of its constituents. The term phase refers to a homogeneous mass of material, such as an aggregation of grains of identical unit cell structure in a solid metal. The usual structure of a composite consists of particles or fibers of one phase mixed in a second phase, called thematrix.

Composites are found innature (e.g., wood), and they can be produced synthetically. The synthesized type is of greater interest here, and it includes glass fibers in a polymer matrix, such as fiber-reinforced plastic; polymer fibers of one type in a matrix of a second polymer, such as an epoxy-Kevlar composite; and ceramic in a metal matrix, such as a tungsten carbide in a cobalt binder to form a cemented carbide cutting tool.

Properties of a composite depend on its components, the physical shapes of the components, and the way they are combined to form the final material. Some composites combine high strength with light weight and are suited to applications such as aircraft components, car bodies, boat hulls, tennis rackets, and fishing rods. Other composites are strong, hard, and capable of maintaining these properties at elevated temperatures, for example, cemented carbide cutting tools.

(Mikell P.Groover, Fundamentals of Modern Manufacturing , materials,processes, and systems third edition page 10)

5) Polymer-matrix Composite(Material)

Polymer-matrix composites (abbreviated PMC) can be classified according to whether the matrix is a thermoset or a thermoplastic polymer. Thermoset matrix composites are traditionally far more common, but thermoplastic-matrix composites are currently the focus of rapid development. The advantages of thermoplastic-matrix composites compared to thermoset-matrix composites in-clude the following:

Lower manufacturing costs:

·         No cure

·         Unlimited shelf-life

·         Reprocessing possible (for repair and recycling)

·         Fewer health risks due to chemicals during processing

·         Low moisture content

·         Thermal shaping possible

·         Weldability (fusion bonding possible).

Better performance:

·         High toughness (damage tolerance)

·         Good hot/wet properties

·         High environmental tolerance.

The disadvantages of thermoplastic-matrix composites include the following:

·         Limitations in relation to processing methods

·         High processing temperatures

·         High viscosities

·         Prepreg (collection of continuous fibers aligned to form a sheet that has been impregnated with the polymer or polymer precursor) is stiff and dry when a solvent is not used (i.e., not drapeable or tacky)

·         Fiber surface treatments less developed.


      Fibrous polymer-matrix composites can be classified according to whether the fibers are short or continuous. Continuous fibers have much more effect than short fibers on the composite’s mechanical properties, electrical resistivity, thermal conductivity, and on other properties too. However, they give rise to composites that are more anisotropic. Continuous fibers can be utilized in unidirectionally aligned tape or woven fabric form. Polymer-matrix composites are much easier to fabricate than metal-matrix, carbon-matrix, and ceramic-matrix composites, whether the polymer is a ther-moset or a thermoplastic. This is because of the relatively low processing temper-atures required to fabricate polymer-matrix composites. For thermosets, such as epoxy, phenolic, and furfuryl resin, the processing temperature typically ranges from room temperature to about 200°C; for thermoplastic polymers, such as poly-imide (PI), polyethersulfone (PES), polyetheretherketone (PEEK), polyetherimide (PEI), and polyphenyl sulfide (PPS), the processing temperature typically range from 300 to 400°C.

Deborah D. L. Chung, Composite Materials Science and Applications, pg 24.


Previous Description


Polymer Matrix Composite (PMC)
A polymer matrix composite (PMC) consists of a thermoset or thermoplastic resin matrix reinforced by fibers that are much stronger and stiffer than the matrix. PMCs are attractive because they are lighter, stronger, and stiffer than unreinforced polymers or conventional metals, with the additional advantage that properties and form can be tailored to meet the needs of a specific application. High-performance fiber reinforcements are of the highest interest for military and aerospace composite applications; these incude carbon fibers and such organic fibers as aramids, liwuid crystalline polymers, and ultrahigh-molecular-wieght polyethylene. (High Performance Structural Fibers For Advanced Polymer Matrix Composites, National Research Council, p.1)
Preform Molding
In preform molding, a dry mat of the reinforcing material is performed to the approximate shape of the part and placed into the open mold. Resin is added to the perform, and the mold halves are then pressed together and heated to cure the part. During the process the resin flows, impregnating the perform, and becomes hard. The cured part is removed after the mold is opened (often with the assistance of knockout pins that are built into the mold). In a variation on the standard method, preimpregnated chopped fibers are blown onto the perform and then cured.(Handbook of Composite Reinforcements, Lee, p.323)
Pulforming
Thepultrusion process islimited to straight sections of constant cross section. There is also a need for long parts which continuous fiber reinforcement that are curved rather than straight and whose cross sections may vary throughout the length. The pulforming process is suited to these less regular shapes. Pulforming can be defined as pultrusion with additional steps to form the length into a semicircular contour and alter the cross sestion at one or more locations along the length. After exiting the shaping die, the continuous workpiece is fed into a rotating tabe with negative molds positioned around its periphery. The work is forced into the mold cavities by a die shoe, which squeezes the cross section at various locations and forms the curvature in the length. The diameter of the table determines the radius of the part. As the work leaves the die table, it is cut to length to provide discrete parts. Resins and fibers similar to those for pultrusion are used in pulforming. An important application of the process is production of automobile leaf springs. (Fundamentals of Modern Manufacturing, 4th Edition, Groover, p.340)
Side-by-Side Mills (in Roll Forming)
Mills with the side-by-side arrangement of the stands are commonly used as rail-and-structural steel and heavy-section mills.
The side-by-side mills are less costly, but have a substantial drawback. Roll speed is the same in all the stands; as strip length increases after each pass, the final stand becomes a bottleneck. Because of this, the rolling rate in these mills is quite low.(Iron and Steel Production, Bugayev, p.167)

Serkan Orhan, 030070165, 1st Week

Previous Description

Wire Frame- All of the edges of the model are visible as solid lines. However, this image can be ambiguous, particularly for complex shapes. Therefore, various colors generally are used for different parts of the object to make it easier to visualize.

(Kalpakjian S., Schmid S.R., Manufacturing engineering and technology, p. 1196)

1)Wireframe [Group: design technique] [Better]

Wireframes derive their name from the frameworks that sculptors and modelers use to provide the starting shape of three-dimensional work; the artist then "fleshes out" the design with clay or other material, just as you will "flesh out" your design with higher-fidelity content as you progress through the iterative prototyping process. Excel provides the framewor for building and refining your wireframes.

(Effective Prototyping with Excel: A Practical Handbook for Developers and Designers,Nevin Berger,Michael Arent,Jonathan Arnowitz, 2009, chapter 6)

Previous Description

Amorphous Polymers
Amorphous polymers are generally useful only if ther Tg is above ambient temperature; otherwise they creep in service. This means that strains imposed during thermoforming need not be plastic since quenching from the forming temperature, which is above Tg, can freeze the viscoelastic deformation. so amorphous thermoplastics are thermoformed just above Tg and cooled in the die to 'fix' the shape. this enables relatively low temperatures and low cycle times to be used.
(Edwards, L., Endean M., MAterials in Action Series: Manufacturing With Materials,1995,pg.194) 

2)Amorphous Polymers [Group:Material] [Better]

Amorphous Polymers is the term used that means formless describing a TP(Thermoplastic) having no crystalline in Fig.1.25. They are normally transparent. They form no pattern whereby their structure tends to form like spagetti; their molecules go in all different directions. These TPs have no sharp melting point and are usually glassy and transparent such as polystyrene (PS) and acrylic (PMMA). If they are rigid, they may brittle. Plastics during processing are normally in the amorphous state with no definite ordder of molecular chains. For TPs that normally crystallize, they may not be properly quenched and result is an amorphous or partially amorphous solid state; usually resulting in inferior properties.

(Plastics Engineering, Manufacturing & Data Handbook, Dominick V. Rosato,Donald V. Rosato,Plastics Institute of America,Marlene G. Rosato,Nick R. Schott,p. 78)

Previous Description

Free - Form Fabrication (Better description)

In 1984, the first commercial free - form fabrication system was introduced by 3D Systems. This technology, called stereolithography, and dozens of competing technologies which followed it, create physical objects directly from 3D CAD models, and can be thought of as "three - dimensional printing." This collection of technologies is offen called rapid prototyping. Most of technologies work by constructing an object, one cross - sectional layer at a time, by depositing a material or by using a laser to selectively solidify a liquid or powder. The resulting parts are most offen made from plastics, but other materials are avaliable, including wax, paper, ceramics and metals. In some cases the parts are used directy for visulation or in working prototypes. However, the parts are offen used as a patterns to make molds or patterns from which parts with particular material properties can then be molded or cast.

Free - form fabrication technologies enable realistic 3D prototypes to be created earier and less expensively than was possible before.

(Kalpakjian S. , Schmid S.R. , Manufacturing Engineering and Technology, p. 258)

3) Free - Form Fabrication [Group: Process]

Free - Form Fabrication is the NNS processing of materials by sequentially stacking thin layers until complicated and 3-D shapes are produced. The operation is computer-controlled and requires no mold. This exciting new field of technology provides engineers with the ability to rapidly produce prototype parts directly from CAD drawings, and little or no machining is necessary after fabrication.

( Innovations in Materials Manufacturing, Fabrication, and Environmental Safety,Mel Schwartz, 2011, p. 375)

Previous Description

ISO 9000 standard 

(Quality Management and Qualitu Assurance Standards) is a deliberately generic series of quality-system management standards. The ISO 9000 standard permanently has influenced the manner in which manufacturing companies conduct business in world trade and has become the world Standard for quality.

The ISO 9000 series includes the following standards:

ISO 9001-Quality systems: Model for quality assurance in design/development, production, installation, and servicing

ISO 9002-Quality systems: Model for quality assurance in production and installation.

ISO 9003- Quality systems: Model for quality assurance in final inspection and test.

ISO 9004- Quality management and qualit system elements: Guidelines.

(Kalpakjian S., Schmid S.R.,Manufacturing Engineering and Technology, 5th Edition, pg.1119)

4)ISO 9000 standard [Group: Standards] [Better]

ISO 9000 is not a product standard but a quality system standard. It applies not to products or services but to the process that creates them. It is designed and intended to apply to virtually any product or service made by any process anywhere in the world.

To achieve this generic state, ISO 9000 refrains, to the greatest extent possible, from mandating specific methods, prectices, and techniques. It emphasizes principles, goals, and objectives. All these focus on one objective, the same objective that drives every business: meeting customer expectations and requirements.

A well-designed, well-implemented, and carefully managed ISO 9000 quality system provides confidence that the output of the process will meet costomer expectations and requirements. It is aimed at providing that confidance to three audiences:

• The customers directly
• The customers indirectly, via third-party audits and quality system registration
• Company management and staff

ISO 9000 does so by requiring that every business activity affacting quality be conducted in a three part never-ending cycle of planning, control, and documentation.

ISO 9000: the year 2000 and beyond,Perry L. Johnson,Perry ,1999, p. 6)

Previous Description

Cast Irons

Cast irons are iron-carbon silicon alloys, typically containing 2% to 4% C and 0.5% to 3% Si, that pass through the eutectic reactions during solidifications.There are 5 types of cast irons:

·         Gray Cast irons contain small, interconnected graphite flakes that cause low strength and ductility.

·         White cast irons are a hard, brittle alloy containing massive amounts of Fe3C.

·         Malleable cast irons are formed by the heat treatment of white iron, produces rounded clumps of graphite.

·         Ductile or nolular cast irons contain spheroidal graphite particles obtained during solidification.

·         Compacted graphite cast iron contains rounded but interconnected graphite also produced during solidification.

(The Science and Engineering of Materials 3rd edition, Donald R. Askeland, page 365)

5)Cast Irons [group: Material] [better]

The  term of cast iron, like the term steel, identfies a large family of ferrous alloys. Cast irons are multicomponent ferrous alloys, which soldify with a eutectic. They contain major(iron,  carbon, silicon), minor(<0.1%), and often alloying (>0.1%) elements. Cast iron has higher carbon and silicom contents than steel. Because of the higher carbon content, the structure of cast iron exhibits a richer carbon phase than that of steel. Depending primarily on composition, cooling rate, and melt treatment, cast iron can solidify according to the thermodynamical metastable Fe-Fe₃C system or the stable iron-graphite sytem. When the metastable path is followed, the rich carbon phase in the eutectic is the iron carbide; when the stable solidification path is followed, rich carbon phase graphite. Refering only to the binary Fe-Fe₃C or iron-graphite system, cast iron can be defined as an iron- carbon alloy with more than 2% C.

The formation of stable or meta stable eutectic is a function of many factors, including the nucleation potential of the liquid, chemical composition, and cooling rate. The firs two factors determine the graphitization potential of the iron. A high graphitization potential will result in irons with graphite as the rich carbon phase, while a low graphitization potential will result in with iron carbide. A shematic of the structure of the common types of commercial cast irons, as well as processing required to obtain them, is shown in Fig.1.

(Cast irons,Joseph R. Davis,ASM International. Handbook Committee,pp3-4)

Erdem Tubun, 503101306, 1st Week Words (24.02.2012)

1-Computer aided production management (CAPM)

2-Master Production Schedule (MPS)

3-Rough-Cut Capasity Planning

4-Hot Isostatic Pressing (HIP)

5-Data Input for NC machines

6-Data Output for NC machines

7-Numerically controlled robot

8-Transfer machines

9-Transfer mechanism and transfer lines

10-Derivative system for CAPP systems

Gökhan GÜNGÖR 514101006 (1st Week Terms)

1. Rail Guided Vehicle
2. Gantry Robot
3. Local Area Networking (LAN)
4. Direct Numerical Control
5. Distributed Numerical Control
6. 3D Digitizing
7. Computer Aided Manufacturing
8. Finite Element Analysis
9. Laser Interferometer Measuring Systems
10. Laser Telemetric Measuring Systems

Ürfet Demirkan-503111315-1st week

1. Computer integrated manufacturing

2. Modelling

3. Solid model

4. Surface model

5. Programming language

6. Geometric tolerancing

7. Sensitivity

8. Precision

9. Kaizen

10. Mechanization

Selçuk Keser - 503111312 - 1st week words

1. Synchronous Manufacturing
2. Eror proofing
3. Free form fabrication
4. Manufacturing cell
5. Small-batch production
6. AGV
7. Bed of nails device
8. Powerhead production unit
9. Interpolation
10. Wire frame 

MÜGE BAŞARAN 030090704 , 5 ANSWERS OF 1ST WEEK WORDS

1-    Random sampling (in statistical quality control)/ (Quality Control)

Previous definition:

Taking a sample from a population or lot in which each item has an equal change of being included in the sample. Thus, when taking samples from a large bin, the inspector should not take only those that happen to be within reach.

(Kalpakjian S., Schmid S.R., Manufacturing engineering and technology, Ed. 5th, p. 1121)

Current Definition:

      The units selected for inspection from the lot should be chosen at random, and they should be chosen at random, and they should be representative of all the items in the lot. The random-sampling concept is extremely important in acceptance sampling. Unless random samples are used, bias will be introduced. For example, the vendor may ensure that the units packaged on the top of the lot are of extremely good quality, knowing that the inspector will select the sample from the top layer. ‘’Salting’’ a lot in this manner is not a common practice, but if it occurs and nonrandom-sampling methods are used, the effectiveness of the inspection process is destroyed.

The technique often suggested to draw a random sample is to assign a number to each item in the lot. Then n random numbers are drawn, where the range of these numbers is from 1 to  the maximum number of units in the lot. This sequence of random numbers determines which units in the lot will constitute the sample. Random numbers can be conveniently generated from a computer, from many hand-held calculators, or from tables of random numbers such as in Appendix IX. If products have serial or other code numbers, these numbers can be used to avoid the process of actually assigning numbers to each unit. Another possibility would be use a three-digit random number to represent the length, width, and depth in a container. For example, the random number 482 could represent the unit located on the fourth level, eighth row, and second column of the container.

In situations where we cannot assign a number to each unit, utilize serial or code numbers, or randomly determine the location of the sample unit, some other technique must be employed to ensure that the sample is random or representative. Sometimes the inspector may ‘’stratify’’ the lot. This consists of dividing the lot into strata or layers and then subdividing each strata, into cubes, as shown in Figure 13-1. Units are then selected from within each cube. While this stratification of the lot is usually an imaginary activity performed by inspector and does not necessarily ensure random samples, at least it ensures that units are selected from all locations in the lot.

Introduction to Statistical Quality Control  2nd Edition , Douglas C. Montgomery, Pg. 555

Mustafa İnan Kütüphanesi               TS156 .M66 1991

2-    Scheduling (in flexible manufacturing systems)

Previous definition:

Because FMS involves a major capital investment, efficent machine utilization is essential. Machines must not stand idle. Consequently, proper scheduling and process planning are crucial. Scheduling for FMS is dynamic, unlike that in job shops where a relatively rigid schedule is followed to perform a set of operations. The scheduling system in FMS specifies the types of operations to be performed on each part and identifies the machines or manufacturing cells where these operations are to take place. Dynamic scheduling is capable of responding to quick changes in product type; hence, it is responsive to real - time decisions.

(Kalpakjian S. , Schmid S.R. , Manufacturing Engineering and Technology, p. 1223)

Current Definition:

Scheduling is the process of organizing,  choosing and timing resource usage to carry out all the activities necessary to produce the desired outputs of activities and resources.  In an FMS, the objective of scheduling is to optimise the use of resources so that the overall production goals are met.  A Fuzzy Based Scheduling Model for FMS which is developed here aims at making  real-time control decisions that include dynamic scheduling and variable part routing used to solve scheduling problems in FMS environments.  Attempts will be made to use a an industrial implementation for experimentation.  Otherwise the model will be verified using data from literature.

Process planning and scheduling are important manufacturing planning activities which deal with resource utilization and time span of the manufacturing operations. In order to cope with competitiveness and globalization of today’s business environment, supply chains become more complex, and manufacturing processes have become more advanced, however products have to be manufactured in higher varieties and smaller batches. It is essential to establish effective and efficient process plans and production schedules to cope with the highly dynamic manufacturing requirements. Some automobile manufactures are gradually adopting their production ways to support the diversity of the customer needs and increase the changing speed for the developing the new products [1].

1.    Scheduling of Flexible Manufacturing Systems  Using Fuzzy Logic by Pramot Srinoi

A/Prof. Ebrahim Shayan  Dr. Fatemeh Ghotb, School of Mathematical Sciences      pg. 95

2.    Manufacturing systems and technologies for the new frontier [electronic resource] : the 41st CIRP Conference on Manufacturing Systems, May 26-28, 2008, Tokyo, Japan / Mamoru Mitsuishi, Kanji Ueda, Fumihiko Kimura, editors, pg. 269

3-    Product quality /(Quality Control and Manufacturing)

Previous definition:

       In view of rhe global economy and competition, a major priority in produckt quality is the concept of continuous improvement as ezemplified by japanese term kaizen,meaning never ending improvement.Still the level of quality that a manufacturer chooses for its products depends on the market for whichthe products are intended.Low cost,low quality products have their own market niche,just as there is a market for high quality,expensive products,such as a high precision machine tool, a rolls royce automoile, a private airplane or yacht or sporting equipment.

   

Kalpakjian, S., Schmid, S. R., Manufacturing Engineering and Technology, 5th ed., p. 1242

Current definition:

The collection of features and characteristics of a product that contribute to its ability to meet given requirements. Early work in controlling product quality was on creating standards for producing acceptable products. By the mid-1950s, mature methods had evolved for controlling quality, including statistical quality control and statistical process control, utilizing sequential sampling techniques for tracking the mean and variance in process performance. During the 1960s, these methods and techniques were extended to the service industry. During 1960–1980, there was a major shift in world markets, with the position of the United States declining while Japan and Europe experienced substantial growth in international markets. Consumers became more conscious of the cost and quality of products and services. Firms began to focus on total production systems for achieving quality at minimum cost. This trend has continued, and today the goals of quality control are largely driven by consumer concerns and preferences.

McGraw-Hill Concise Encyclopedia of Engineering. © 2002 by The McGraw-Hill Companies, Inc.,pg. 559

4-    Interpolation /(Manufactoring / automation)

Previous definition is not found on the web page !!

Current definition:

Movement along the path (interpolation) occurs incrementally by one of several basic methods (Fig. 37.11). Examples of actual paths in drilling, boring and milling operations are shown in the  Fig. 37.12.   In all interpolations, the path controlled is that of the center of rotation of the tool. Compensation for different types of tools, for different diameters of tools, or for tool wear during machining can be made in the NC program.

·      In linear interpolation , the tool moves in a straight line from start to end (Fig.37.11a) along two or three axes. Theoretically, all types of profiles can be produced by this method by making the increments between the points small (Fig.37.11b). However , a large amount of data has to be processed in order to do so.

·      In circular interpolation( Fig. 37.11c), the inputs required for the path are the coordinates of the end points, the coordinates of the center of the circle and its radius, and the direction of the tool along the arc.

·      In parabolic interpolation and cubic interpolation, the path is approximated by curves using higher-order mathematical equations. This method is effective in 5-axis machines and is useful in die sinking operations for the sheet- forming of automotive bodies. These interpolations also are used for the movements of industrial robots.

(Manufacturing Engineering and Technology 5^th Edition , Serope Kalpakjian, Steve R. Schmid, Pg. 1158)

5-    Low cycle  Fatigue/ (Material)

Previous definition

The cyclic loads are relatively high, significant amount of plastic strain are induced during each cycle, and short lives or low numbers of cycles to failure are exhibited if these relatively high loads are repeatedly applied. This type of behavior has been commonly called low-cycle fatigue or, more recently, cyclic strain-controlled fatigue. The transition from low-cycle fatigue behavior to high-cycle fatigue behavior generally occurs in the range from about 10^4 to 10^5 cycles, and many investigators now define the low-cycle fatigue range to be failure in 50000 cycles or less.

Failure of Materials In Mechanical Design, Jack A. COLLINS, John Wiley & Sons, 1993, Second Edition, p.393

Current Definition:

      The phenomenon of low cycle fatigue can be in principle described in terms of the theory of plasticity. In fact, low-cycle fatigue is a cyclic elastoplastic deformation occurring until the expenditure of plasticity reserves. The material behavior at unloading and reversed loading, in particular the shape and size of hysteresis loops, is of essential significance in low-cycle fatigue. The relation between maximal stress and strain within a cycle generally differs from that in monotonic quasistatic loading. The cycle-deformation relations depend on the type of loading process. They change whether this process is load- or displacement-controlled loading the maximal cycle stresses grow with the cycle number. Other materials reveal a tendency to cyclic softening. An intermediate place is occupied by the so-called plastically stabilizing materials. Depending on the microstructural state and temperature, the same material may behave in various ways. Typical diagrams of uniaxial tensile/compression deformation σ(ε) are shown in Figure 1.8. They correspond to symmetrical cycle loading with the given strain amplitude  . Figure 1.8a shows the behavior of a cycle-dependent hardening material; Figure 1.8b that of a softening material.

      When the strain level is high, cycle number at fatigue failure is comparatively small, and significant one-sided residual deformations accumulate in the specimen. At a moderate strain level, teat results are convenient to represent with fatigue curves. Compared with high-cycle fatigue curves, low-cycle fatigue curves are usually plotted on the plane of characteristic strain versus cycle number at failure. Standard test in tension or tension/compression are usually performed maintaining a constant range Δε of the nominal (average upon all the working parts of a specimen) strain ε.

   

Mechanics of fatigue / Vladimir V. Bolotin, Boca Raton : CRC Press, c1999 , pg. 9,10,11

Mustafa İnan Kütüphanesi               TA418.38 .B65 1999