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)