Complex Systems

Larger-scale products such as automobiles and airplanes are complex systems comprised of many interacting subsystems and components. When developing complex systems, modifications to the generic product development process address a number of system-level issues. The concept development phase considers the architecture of the entire system, and multiple architectures may be considered as competing concepts for the overall system. The system-level design phase becomes critical. During this phase, the system is decomposed into subsystems and these further into many components. Teams are assigned to develop each component. Additional teams are assigned the special challenge of integrating components into the subsystems and these into the overall system. Detail design of the components is a highly parallel process in which the many development teams work at once, usually separately. Managing the network of interactions across the components and subsystems is the task of system engineering specialists of many kinds. The testing and refinement phase includes not only system integration, but also extensive testing and validation at all levels. References and Bibliography Many current resources are available on the Internet via www.ulrich-eppinger.net Stage-gate product development processes have been dominant in manufacturing firms for the past 30 years. Cooper describes the modem stage-gate process and many of its enabling practices. Cooper, Robert G., Winning at New Products: Accelerating the Process from Idea to Launch, third edition, Perseus Books, Cambridge, MA, 2001.

Examples of thermoplastics and their characteristics

Examples several types of thermoplastic with the characteristics.

- Poly Vinyl Chlorid (PVC)

Material properties:

a. Hard PVC

Thermoplastic, hard, rigid, transparent, capable of welding and glueing. Resistant to oil, acids, language, alcohol, but less resistant to solvents such as acetone, benzol, esters, temperature resistant up to 80 ° C.

b. Soft PVC

Greatly influenced by the amount of material given the softness softener that occur from such skin becomes rubbery. Clay, crack resistant, capable of being used to a temperature of 80 ° C, while the resistance to chemical solution under the hard PVC.

- Poly Styrol (PS)

Thermoplastics, such as glass, easy to be colored, at room temperature is relatively hard and rigid. Odorless and flammable, resistant to water, acids, bases, alcohols, oils but soluble in benzol, gasoline, acetone, ether. Can be glued and welded.

- Poly Methyl Metha Crylat (PMMA)

Thermoplastic, hard, brittle, scratch resistant, looks like glass, translucent, wear resistant, lightweight, easy to be colored, odorless, resistant to mild acids, alkalis, gasoline and oil, but not resistant to solvents.

- Poly Ethilen (PE)

Thermoplastic, soft material, clay, capable of working up to -40 ° C, low water absorption, resistant to acids, bases, solvents, alcohol, gasoline, water, oil, but do not hold HcIO and flammable.

- Polyamide (PA)

The name of the market is Nylon, thermoplastic properties, ductile at 2% -3% humidity, hard, brittle and stiff in the dry state. Color yellowish, opaque and easily colored. Able welded and glued also able to work on - ^ 40 ° C - 110 ° C.

- Polycarbonate (PC)

Thermoplastics, such as glass, capable of bouncer, capable of machining high, the shape does not change until heated at a temperature of 135 ° C, non-flammable, resistant to acids software (not concentrated), oil, gasoline and alcohol, are not resistant to alkali and solvents.

- Silicone (Si)

Heat resistant, have physical and chemical properties are very good, waterproof, capable diginakan at -90 ° C - 250 ° C, insulation material, material loading compactor for high humid areas.

- Polyurethane (PUR)

Is Elastomere, elastic like rubber, rub-resistant, scratch resistant, can be used at a temperature of -30 ° C - 80 ° C, resistant to oil, fuel, not acid resistant, alkali, solvents, hot water and flammable.

- Epoxydeharze

Elastomere, until light golden yellow color, hard and easy to work with machinery, resistant to weather changes and can be used up to 110 ° C, high electrical pengisolir, hold the soft acid, alkaline alcohol, oil, solvents, soluble in acetone and the Flammable .

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Quick-Build Products

For the development of some products, such as software and many electronics products, building and testing prototype models has become such a rapid process that the design-build-test cycle can be repeated many times. In fact, teams can take advantage of rapid iteration to achieve a more flexible and responsive product development process, sometimes called a spiral product development process. Following concept development in this process, the system-level design phase entails decomposition of the product into high-, medium-, and low-priority features. This is followed by several cycles of design, build, integrate, and test activities, beginning with the highest-priority items. This process takes advantage of the fast prototyping cycle by using the result of each cycle to learn how to modify the priorities for the next cycle. Customers may even be involved in the testing process after one or more cycles. When time or budget runs out, usually all of the high- and medium-priority features have been incorporated into the evolving product, and the low-priority features may be omitted until the next product generation.
References and Bibliography
Many current resources are available on the Internet via www.ulrich-eppinger.net
Stage-gate product development processes have been dominant in manufacturing firms for the past 30 years. Cooper describes the modem stage-gate process and many of its enabling practices.
Cooper, Robert G., Winning at New Products: Accelerating the Process from Idea to Launch, third edition, Perseus Books, Cambridge, MA, 2001.
 

Thermoplastic materials

Two main categories of Thermoplastic materials are amorphous and Crystaline. While some materials classified in other categories and some of the material is a combination of both. Polymers like Polymethylmethacrylate, Polycarbonate and Polystyrene is an amorphous polymer chains, ie with a random molecular chain structure and become actively engaged in a wide temperature range. This means that the material is not called liquid but more accurate to say softened. And this material begins to soften so heating is carried out. Increasingly soft as the heat absorbed, until finally absorbing a lot of heat and eventually called the "melting".




Amorphous polymers do not have a specific melting point. At low temperatures they are hard, dense, brittle and luster, at high temperatures such as rubber or leather. Temperature when the transition occurs is called the Glass-Transition Temperature (Tg), also called Point glass or glass temperature.

In Crystaline material, regular molecular chain structure and become active only after the material is heated to its melting point. This means that these materials do not pass through a phase softened, but remained solid until heated at certain temperature and instantly melted material.



Differences property amorphous and Crystaline


Amorphous

* Net

* Low Shrinkage

* Softened

* The high mashed

* Lack of chemical resistant


Crystaline

* Opaque

* Depreciation high

* Melt

* Low Power mashed

* Hold chemicals



Examples of materials based on molecular structure


Amorphous

* ABS

* Acrylic

* Polyamide

* Polyacrylate

* Polycarbonate

* Polystyrene

* Polyurethane


Crystaline

* Acetal

* Nylon

* Polyester (PBT)

* Polyethylene

* Polyethyleneterephthalate (PET)

* Polypropylene

* Polyvinylcloride (PVC)



To improve the ductile properties of amorphous glass below its transition temperature we can mix it with some elastomers. This is known as an elastomer polymers dimodofikasi into rubber. Some examples of the elastomer is Acrylates, Butyls, Fluorosilicon, Fuorocarbons Polysulfids polyurethane.

The ability of plastics to return to his native structure after heating and then softened or melted in other words, reversible process called Thermoplastic. If we raise the temperature above the Tg of his skin then first became such as rubber along with the addition of temperature. finally at a temperature above its melting point at Crystaline become viscous fluid with a viscosity decreases with further increase in temperature. In the liquid phase resembles a plastic ice cream can be formed. Because of its recyclable plastic can then be formed up to several times, but repetition of heating and cooling causes the reduction in the quality of the plastic.

When Thermoplastic deformed or are interested, this process is called orientation. Like the metal polymer becomes anisotropic. Specimens become more powerful and solid in the direction of pull than the transverse direction. Another important thing is the ability of water-absorbing polymer. Water makes the plastic becomes more plastic. With the addition of moisture, Glasstransition Temperature, voltage and modulus of elasticity will be lower. Dimensional changes also occur due to moisture environment.


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