Ufuk Civelek, 030050161, 9th Week

1)Flux Cored Arc Welding(Welding technique)

http://www.robot-welding.com/arc_weld_processes.htm

Flux Cored Arc Welding is a fusion welding process in which weld heating is produced from an arc between the work and a continiously fed filter metak electrode. Atmosferic shielding is provided in complately or in part by the flux sealed within the tubular electrode.Extra shielding may or may not supplied through a nozzle in the same way in GASW.

Although the process was introduced in 1950's it represented less than % 5 of the total amount of welding done in 1965. In 2005 it passed the %50 of mark and still is rising

Advantages.
High Deposition Rate
Minimum Electrode aste
Ecellent controll.
Larry Jeffus,Lawrence Bower,Welding Skills, Processes and Practices for Entry-Level Welders, P.114



Flux Cored Arc Welding(new)(better)

FIux-cored arc welding (FCAW) overcomes some of the limitations of the shielded metal arc process by movlng the powdered flux to the lnterior of a continuous tubular electrode (Figure 31-13), When the arc is established, the vaporizing flux again produces a protective atmosphere and also forms a slag layer over the weld pool that wil require subsequent removal.Alloy additions (metal powders) can be blended into the flux to create a wide variety of filler metal chemistries. Compared to the stick electrodes of the shielded metal arc process, the flux-cored electrode is both continuous and less bulky,since binders are no longer required to hold the flux in place.

The continuous electrode is fed automatically through a welding gun, with electrical contact being maintamed through the bare-metal exterior oi the wire at a position near the exit of the gun. Overheating of the electrode is no longer a problem, and welding currents can be increased to about 500 A. The higher heat input increases penetration depth to about 1 cm. The process is best used for welding steels, and welds can be made in all position. Direct-current electrode-positive (DCEP) conditions are almost always used for enhanced penetration.High deposition rates are possible but the equipment cost is greater than that of SMAW because of the need for a controlled wire feeder and more costly power suply. Good ventilation is required to remove the fumes generated by the vaporizing flux.

In basic flux-cored arc welding process the shielding gas is provided by the vaporization of flux components. Better protection and cleaner welds can be produced by combining the flux with a flow of externally supplied shieldining gas such as CO2.
(DeGarmo's Materials and Processes in Manufacturing, J. T. Black,Ronald A. Kohser, p.854)

2)Wire Bonding(new)(joining technique)

The wire bonding is a joining technique to produce discrete electrical contacts, in general, from the die onto substrate, where the lateral bridging as well as the height difference between the two surfaces have to be overcome.
To wire bond, the components to be joined must show suitable contact surfaces (so called “landing pads”). The requirements of suitable junction technique for the hybrid technology are a good, stable electrical junction, small space requirement for junction points, low mechanical and thermal loading of the component, as well as cost effectiveness and compatibility to the manufacturing processes. For the development of a mature bond technology, expensive metallurgical experiments and developments of special apparatus to handle the junction wires were necessary. The wires used are normally made of gold or aluminium alloy with diameters of down to 10 μm. All wire-bonding processes are similar in that theyrub off the oxide skin of wire by introducing pressure, heat and ultrasonic energy. The joining partners (wire-contact surface) are brought into such a close contact that the van der Walls forces become effective and a stable junction is made possible. To wire-bond in practice, the following processes have proven to be effective.
(Microsystem Technology, Wolfgang Menz, p.413)

Eski terim bulunamadı.

3)Material handling and storage (Manufacturing)

There has been impressive progress in automated material handling and storage systems. Material handling systems are used to increase the speed of material movement, weight carried, distance travelled, and ability to deal with a harsh enviroment. This section discusses the major trends in material handling and storage technology.
-Material handling technology: The future developments in material handling aim at better control inventory, improved production felexibility, and fully integrated manufacturing systems.
-Automated Storage Systems: The development in material storage technology are strongly affected by the need to reduce the amount of material to be stored.
-Control systems: The progress in material handling control systems includes refinement of sensors, motor starters, communication links, and other methods for direct machine control as well as advance in hardware and software.
(Computational intelligence in design and manufacturing, A. Kusiak, p.7) 


Material handling and storage(new)(better)

The second major component of an FMS is its material handling and storage system. In this subsection, we discuss the functions of the handling system, material handling equipment typically used in an FMS, and types of FMS layout.

Functions of the Handling System. The material handling and storage system in an FMS performs the following functions:

• Random, independent movement of workparts between stations. This means that parts must be capable of moving from any one machine in the system to any other machine. to provide various routing alternatives for the different parts and to make machine substitutions when certain stations are busy.

•Handle a variety of workpart configurations. For prismatic parts, this is usually accomplished by using modular pallet fixtures in the handling system. The fixture is located on the top face of the pallet and is designed to accommodate different part configurations by means of common components, quick-change features, and other devices that permit a rapid build-up of the fixture for a given part. The base of the pallet is designed for the material handling system. For rotational parts, industrial robots are often used to load and unload the turning machines and to move parts between stations.

• Temporary storage. The number of parts in the FMS will typically exceed the number of parts actually being processed at any moment. Thus, each station has a smallqueue of parts waiting to be processed. which helps to increase machine utilization.

• Convenient access for loading and unloading workparts. The handling system must include locations for load/unload statiuus.

• Compatible with computer control. The handling system must be capable of being controlled directly by the computer system to direct it to the various workstations, load/unload stations, and storage areas

Material Handling Equipment. The types of material handling systems used to transfer parts between stations in an FMS include a variety of conventional material transport equipment (Chapter 10), in-line transfer mechanisms (Section 18.1.2),and industrial robots (Charter 7) The material handling function in an FMS is often shared between two systems: (1) a primary handling system and (2) a secondary handling system. The primary handling system establishes the basic layout of the FMS and is responsible for moving workparts between stations in the system.

The secondary handling system consists of transfer devices, automatic pallet changers. and similar mechanisms located at the workstations in the FMS.The function of the secondary handling system is to transfer work from the primary system to the machine tool or other processing station and to position the parts with sufficient accuracy and repeatability to perform the processing or assembly operation. Other purposes served by the secondary handling system include: (1) reorientation of the workpart if necessary to present the surface that is to be processed and (2) buffer storage of parts to minimize work change time and maximize station utilization. In some FMS installations, the positioning and registration requirements at the individual workstations are satisfied by the primary work handling system. In these cases, the secondary handling system is not included, The primary handling system is sometimes supported by an automated storage system (Section: 1.4). The FMS is integrated with an automated storage/retrieval system (AS/RS), and the S/R machine serves the work handling function for the workstations as well as delivering parts to and from the storage racks.
(Automation, Production Systems, and CIM, Mikell P. Groover, p.472)

4) Processing operations (Manufacturing)

Processing operations are required to transform the starting material into the final form. The operations are performed in the particular sequence required to achieve the geometry and condition defined by the design specification.Processing operations include shaping operations, property-enhancing operations and surface processing operations.Shaping operations alter the geometry of starting work material by various methods. Common shaping processes include casting, forging and machining.Property enhancing operations add value to the material by improving its physical properties without changing its shape.Heat treatment is most common example.Surface processing operations are performed to clean, treat, coat, or deposit material onto the exterial surface of the work. Common examples of coating are plating and painting.
(Groover M.P., Fundamentals of Modern Manufacturing: Materials, Processes and Systems, p. 12)


Processing operations(new)(better)

Processing Operations. A processing operation uses energy to alter a workpart's shape, physical properties, or appearance to add value to the material. The forms of energy include mechanical, thermal. electrical, and chemical. The energy is applied in a controlled way by means of machinery and tooling. Human energy may also be required, but human workers are generally employed to control the machines. to oversee the operations, and to load and unload parts before and after each cycle of operation. A general model of a processing operation is illustrated in Figure 2.1(a). Material is fed into the process.energy is applied by the machinery and tooling to transform the material, and the completed workpart exits the process. As shown in our model. most production operations produce waste or scrap, either as a natural byproduct at the process (e.g., removing material as in machining) or in the form of occasional defective pieces. An important objective in manufacturing is to reduce waste in either of these forms.
More than one processing operation is usually required to transform the starting material into final form. The operations are performed in the particular sequence to achieve the geometry and/or condition defined by the design specification. Three categories of processing operations are distinguished: (1) shaping operations, (2) property-enhancing operations. and (3) surface processing operations. Shaping operations apply mechanical force or heat or other forms and combinations of energy to effect a change in geometry of the work material. There are various ways to classify these processes. The classification used here is based on the state of the starting material, by which we have four categories:
1. Solidification processes
2. Particulate processing
3. Deformation processes
4. Material removal processes
(Automation, Production Systems, and CIM, Mikell P. Groover, p.33)


 5)Manufacturing automation protocol (MAP)(network standart) (new)

MAP is a hardware/software protocol developed jointly by a group of industries and vendors of computers and PLCs. It follows the ISO OSI model. MAP was developed as a result of the plans of General Motors to automate its factories.
MAP uses a broad band LAN, with a token ring protocol for traffic control. Since it is broadband, all devices in the LAN like computers, CNC machines, robots, and PLC’s etc.share the same cable, but different groups of devices can be placed on separate “channels” on the line. Additionally, closed circuit TV (video) channel can also be accommodated on same cable. MAP physical level is based on the IEEE 802.4 token-bus standard. At the data link level, it uses the IEEE 802.2 logical control standard. MAP also uses 8473 network layer protocol for connectionless-mode network service.
(CAD/CAM/CIM, P. Radhakrishnan, p.536)
Eski terim bulunamadı.