Ahmet Gökay Öztürk 030050143 (12thweek)

Viscoelasticity

Although rubber is highly elastic it is not completely so. The best the chemist can achieve is probably represented by the high bounce rubber ball from the toy store, which is a rubber compound with an extremely high proportion of BR ( Polybutadiene Rubber) and a vulcanization system designed for a high state of cure. The chemist can also design a compound, so that a ball made from it hardly bounces at all; toy stores probably have them too. This low bounce ball is said to have a significant viscous component and a low elastic component. This combination of viscous and elastic properties results in the definition of viscoelasticity.
(Andrew Ciesielski, An Introduction to Rubber Technology, pg.127)


Carbon Black

This is a material of major significance to the rubber industry, so it is no surprise that most rubber products we see in the market place are black in color. We have moved a long way from collecting carbon from smokey oil flames, which produced a material called lampblack. The next historical step was to burn natural gas against iron channels, then scrape off the carbon to produce a highly reinforcing material called channel black. Both the use of this black in the rubber industry and its source of supply is currently limited and its cost is somewhat high. There are two common methods of producing carbon black today. Heating natural gas in a silica brick furnace to form hydrogen and carbon, produces a moderately reinforcing material called thermal black. Alternatively, if we incompletely burn heavy petroleum fractions, then furnace blacks are produced. These are the most important blacks in terms of quantity used and available types
(Andrew Ciesielski, An Introduction to Rubber Technology, pg.37-38)


Automated manufacturing systems

Automated manufacturing systems operate in the factory on the physical product. They perform operations such as processing, assembly, inspection, or material handling, in some cases accomplishing more than one of these operations in the same system. They are called automated because they perform their operations with a reduced level of human participation compared with the corresponding manual process. In some highly automated systems, there is virtually no human participation. Examples of automated manufacturing systems include:
• automated machine tools that process parts
• transfer lines that perform a series of machining operations
• automated assembly systems
• manufacturing systems that use industrial robots to perform processing or assernblyoperations
• automatic material handling and storage systems to integrate manufacturing operations
• automatic inspection systems for quality control
Automated manufacturing systems can be classified into three basic types:
(1) fixed automation. (2) programmable automation, and (3) flexible automation.
(Mikell P. Groover, Automation, Production Systems, and Computer-Integrated Manufacturing (2nd Edition)Systems, pg.10)


Closed loop positioning systems

A closed-loop NC system, illustrated in Figure 6.27(h). uses servomotors and feedback
measurements to ensure that the worktable is moved to the desired position. A common
feedback sensor used for NC (and also for industrial robots) is the optical encoder, shown
in Figure 6.28. An optical encoder consists of a light source and a photodetector on either
side of a disk. The disk contains slots uniformly spaced around the outside of its face. These slots allow the light source to shine through and energize the photodetector. The disk is connected, either directly or through a gear box, to a rotating shaft whose angular position and velocity are to be measured. As the shaft rotates, the slots cause the light source to be seen by the photocell as a series of flashes. The flashes are converted into an equal number of electrical pulses. By counting the pulses and computing the frequency of the pulse train, worktable position and velocity can be determined.
(Mikell P. Groover, Automation, Production Systems, and Computer-Integrated Manufacturing (2nd Edition)Systems, pg.183)