060070103-Rifat Yılmaz- 8th Week Definitions

Mechanical Fasteners (Previous) GROUP: Assembly technology

The mechanical fastening generally requires that the components to be joined have holes through which fasteners such as bolts, screws, rivets, pins, etc. may be inserted and the jointing or clamping results either by screwing the nut on the threaded bolt or by riveting the head of the pin. Mechanical fasteners are preferred over other methods of jointing for the following reasons.

-Ease in manufacturing (drilling or tapping)
-Joint is not permanent and has ease of assembly and disassembling for repairing or maintenance
-Easy to create designs of joints requiring moveable joints such as hinges
-Lower overall cost
-Joints are easy to design to resist tensile and shear loads.

(Manufacturing Processes, Yazar: Kaushish, p.535)

 Mechanical Fasteners (New)(Better)

The primary function of a fastener system is to transfer load. Many types of fasteners and fastening systems have been developed for specific requirements, such as high strength, easy maintenance, corrosion resistance, reliability at high or low temperatures, or low material and manufacturing costs.

Mechanical fasteners are grouped into threaded fasteners, rivets, blind fasteners, pin fasteners, special-purpose fasteners, and fasteners for composites. Rivets, pin fasteners, and special purpose fasteners are usually designed for permanent or semipermanent installation. Threaded fasteners are considered to be any threaded part that, after assembly of the joint, may he removed without damage to the fastener or to the members being joined. Rivets are permanent one-piece fasteners that are installed by mechanically upsetting one end. Blind fasteners are usually multiple-piece devices that can be installed in a joint that is accessible from only one side. When a blind fastener is being installed, a self-contained mechanism, an explosive, or other device forms an upset on the inaccessible side. Pin fasteners are one-piece fasteners, either solid or tubular, that are used in assemblies in which the load is primarily shear. A malleable collar is sometimes swaged or formed on the pin to secure the joint. Special-purpose fasteners, many of which are proprietary, such as retaining rings, latches, slotted springs, and studs, are designed to allow easy, quick removal and replacement and show little or no deterioration with repealed use.

( F. C. Campbell,Joining: Understanding the Basics, page 11)

Limit switches (Contact sensors) GROUP: Sensor type

Switches designed to be turned ON or OFF by an object exerting pressure on a lever or
roller that operates the switch
(Sabrie Soloman, Sensors and Control Systems in Manufacturing, 2nd edition, page 411)

A limit switch is constructed much like the ordinary light switch used
in home and office. It has the same ON/OFF characteristics. The limit
switch usually has a pressure-sensitive mechanical arm. When an
object applies pressure on the mechanical arm, the switch circuit is
energized. An object might have a magnet attached that causes a contact
to rise and close when the object passes over the arm.
(Sabrie Soloman, Sensors and Control Systems in Manufacturing, 2nd edition, page 79)

Limit switches (New)(Better)

Limit switches, which is type of position sensor, are electromechanical contact devices. Easy to understand and ap­ply, they are the cost-effective switches of choice for detecting objects that can be touched. These rugged, dependable switches are offered in a variety of sizes with dif­ferent seals, enclosures, actuators, circuitries and electrical ratings.

Limit switches contain a set of contacts. When a target object comes into contact with a limit switch's actuator on the conveyor in Figure 15.1.1, the switch operates.

(Jon S. Wilson, Sensor Technology Handbook, page 322)

Proximity Detectors (Previous) GROUP: Sensor type

Proximity detectors record the presence of an objective without making physical contact. Proximity detectors are of two types; inductive for detecting the proximity of metals, capacitive for detecting both metals and non-metals.

(Roger HANNAM, Computer Integrated Manufacturing From Concepts to Realisation, 1st Edition, p. 97)

Proximity Detectors (New)(Better)

Proximity detectors are basically metal detectors. They are used to detect the presence or absence of metal without physically touching it. This prevents wear on the unit and gives the detector the ability to sense reel hot metals. Most proximity detectors are designed to detect ferrous metals only, but there are some units that detect all metals.

There are several methods used to make proximity detectors. One method is shown in figure 16-1. This is a very simple circuit intended  to illustrate die principle of operation of a proximity detector. The sensor coil is connected through a series resistor to an oscillator. A voltage detector, in this illustration a voltmeter, is connected across the resistor. Since AC voltage is applied to this circuit, the amount of current flow is determined by the resistance of the resistor and the inductive reactance of the coil. The voltage drop across the resistor is proportional to its resistance and the amount of current flow.

If ferrous metal is placed near the sensor coil, its inductance increases in value. This causes an increase in inductive reactance and a decrease in the amount of current flow through the circuit. When the current flow through the resistor is decreased, the voltage drop across the resistor decreases also (figure 16-2). The drop in voltage can be used to turn relays or other devices on or oil.

This method of detecting metal does not work well for all conditions. Another method, which is more sensitive to small amounts of metal, is shown in figure 16-3. This detector uses a lank circuit limed to the frequency of the oscillator. The sensor head contains two coils instead of one. This type of sensor is a small transformer. When the lank circuit is tuned lo the frequency of the oscillator, current flow around the tank loop is high. This causes a high voltage to be induced into the secondary coil of the sensor head.

(Stephen Herman, Industrial Motor Control, pages 148-149)

Electronic Data Interchange(EDI) (Previous) GROUP:Data management technology

EDI is a concept that has been in commercial use fore more tahn 30 years, ıt is widely accepted by companies all over the world as the way to electronically exchange business data.

Over the years ,we have seen a variety of inter pretations of the term EDI. A common and basic defination of EDI is the transfer of business data between computer applicatios using a mutually agreed standard to describe the data contained in the message. 

(Implementing EDI Solutions, G. Van de Putte, K. Bathini, K. Chandu, IBM Redbooks, 2003, p.2)

Electronic Data Interchange(EDI) (New)(Better)

EDI consists of standardized electronic-message formats (transaction sets) for business documents such as requests for quotations, purchase orders, purchase change orders, bills of lading, receiving advices, and invoices. Computer-to-computer exchange of business information has become an increasingly popular form of electronic commerce. EDI is important because it enables firms to exchange business information faster, more cheaply, and more accurately than is possible using paper-based systems.

EDI is used in manufacturing, shipping, warehousing, utilities, pharmaceuticals, construction, petroleum, metals, banking, insurance, retailing, government, health care, and textiles, among others. EDI was first used in the transportation industry more than twenty years ago, by ocean, motor, air, and rail carriers and the associated shippers, brokers, customs, freight forwarders, and bankers.

A typical EDI configuration will involve translation software (to perform document conversion to a standard format) at all participating sites, with a standard communications package to shuttle the converted documents between locations. On arrival, standard documents are converted again to the internal format, a relatively straightforward business, but with compelling economies of scale.

(Ravi Kalakota, Andrew B. Whinston, Electronic Commerce: A Manager's Guide, pages 376-377)

Non structural adhesives(Previous) GROUP: Joining material

Are characterized by relatively low strenght and poor creep resistance at slightly elevated temperatures.The most common non structural adhesives are based on elastomers and thermoplastics.Altough these systems have low strenght they usually are easy to use and fast setting.Because of this characteristics most non structural adhesives are used in assembly line fastening operations where the ultimate joint strength is not required and enviromental service conditions are not severe.

(Handbook of adhesives and sealants,p:392)

Non structural adhesives(New) (Better)

Nonstructural (or natural adhesives) adhesives are adhesives with lower strength and permanence. They are generally used for temporary fastening or to bond weak substrates such as paper and foam. Examples of nonstructural adhesives are pressure-sensitive tapes, wood glue, elastomers, and sealants. These adhesives are sometimes used for temporary fastening or sealing. They generally have good resistance to heat and chemicals (within their range of usage) but have poor moisture resistance.

(1-Charles A. Harper,Edward M. Petrie, Plastics Materials and Processes: A Concise Encyclopedia, page 17.  2- Kaushish, Manufacturing Processes, page 530)