Ufuk Civelek, 030050161, 10th Week

1) Isothermal Forming (new)(Manufacturing process)

Figure 15-9 shows the reIationship between yield strength (or forging pressure) and temperature for several engineering metals.The 1020 and 4340 steels show a moderate Increase in strength with decreasing  temperature. In contrast, the strength of the titanium alloy (open circles) and the A-286 nickel-based superalloy (solid circles) shows a much stronger variation. Within the range of typtcal hot-working temperatures, cooling of as little as 100°C (200°F) could result in a doubling in strength. During hot forming, cooling surfaces surround a hotter interior. Any variation in strength can result in nonuniform deformation and cracking of the less ductile surface.

To successfully deform temperature-sensitive materials, deformatton may have to be performed under isothermal (constant-temperature) conditions. The dies or tooling must be heated to the same temperature as the workpiece, sacrificing die life for prouct quality. Deformation sp eeds must b e slowed so that any heat generated by deformation c an be removed in a manner that would maintain a uniform and constant temperature. Inert atmospheres may be required because of the long times at eIevated temperature. Although such methods are indeed costly, they are often the only means of producing satisfactory products fram certain materials. Because of the uniform temperatures and slow deformations speeds, isothermally formed components generally exhibit close tolerances, low residual stresses, and fairly uniform metal flow.
(Materials and Processes in Manufacturing, E. Paul DeGarmo,p.377)
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2) Forging Hammers(new)(Manufacturing machine)

Forging hammers  operate by applying an impact loading against the work. The term drop hammer is often used for these machines, owing to the means of delivering impact energy—see Figures 19.19 and 19.20 . Drop hammers are most frequently used for impression-die forging. The upper portion of the forging die is attached to the ram, and lower portion is attached to the anvil. In the operation, the work is placed on lower die, and ram is lifted and the dropped. When the upper die strikes the work, the impact energy causes the part to assume the form of die cavity. Several blows of the hammer are often required achieve the desired change in shape.

Drop hammers can be classified as gravity drop hammers and power drop hammers. Gravity drop hammers achieve their energy by the falling weight of a hevy ram. The force of the blow is determained by the height of the drop and the weight of the ram. Power drop hammers accelarate the ram by pressurized air or steam. One of the disadvantages of drop hammers is that a large amount of the impact energy is transmitted through the anvil and into the floor of the building.

(Fundamentals of Modern Manufacturing:Materials, Processes, and Systems,Mikell P. Groover,p.409)

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3)Quick Response Manufacturing (QRM) (Manufacturing method)

The Quick Response Manufacturing System is based on the quick response concept with the purpose to quick response to the demand for developing new products and carry out of design and manufacturing process in a very timely manner. The frequent changing of market demand requires higher competence of new product development. On one hand, companies need to analyze its current development and manufacturing system to estimate, from the perspective of mission reliability, system' s ability to finish the task in the required time period. On the other hand, companies may also need to improve on those weaknesses that pertain to the system therefore increase its competence of development.

(Computational science, Yong Shi, pg. 202)

Quick response manufacturing (new)(better)

In today’s world of competitive environment, one of the key success factors for manufacturing firms is speed-not only speed of delivery, but of concept, desgn and production. New opportunities open for those manufacturing firms, who can get products to market before the competition and success hinges on the ability to move quickly.

Quick response manufacturing (QRM) is a companywide strategy to cut  a lead times in all phases of manufacturing and office operations. It can bring the manufacturing firms products to market more quickly and secure its business prospects by helping to compete in a rapidly changing manufacturing arena.

QRM will not only make the manufacturing firm more attractive to potential customers; it will also increase profitability by reducing non-value-added time, cutting inventory and increasing return on investment.

Benefits of QRM for manufacturing

• Decreases the manufacturing costs
• ·         Increase the market share 
• Fills customer orders faster
• Boosts product quality
• Introduces new products rapidly
• Eliminates waste and inefficiency
• Secures the manufacturin future of the firm 

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      Thus wee see, that even throuh it is impetitive to apply lean manufacturing to any manufacturing firm, the manufacturing world is moving towards agile manufacturing and quick response manufacturingwhich is the next step for survivalin this competitive era. But to approach agile manufacturing and quick response manufacturing, the company requires to be using lean manufacturing methods, Which is a starting point. Agility can be built only from a firm foundation. Hence the focus of this project is on lean.

(Supply Chain Management: Concepts And Cases, Rahul V. Altekar,p.99)


4) Microgrippers(new) (Manufacturing device)

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      Key to success of todays microdevices was the development of an economic route to fabrication via photolithography. The current trend in microsystems, however, iss toward the integration of components that are incompatiable with standart microfabrication tools. Such components might have a surface chemistry engineered for detecting pathogen, or an elasticity suitable for a leak-tight seat. Clearly complementry approaches to microfabrication are needed.

      One approach to this microfabrication challenge is the assembly of complex, three-dimensional microsystems from heterogenous microcomponents. Such microsystems are often referred as hybrid MEMS. To be cost effective, the assembly of hybrid MEMS must be carried out in an automated and massively parallel fashion. While pick-and-place operations are extreemly common in the manufacturing of macroscale objects(> 1mm3), they are exceedingly difficult for objects in the size range of 1 to 100 microns. At these scales, adhesion forces become much greater then inertial forces, making it difficult to grasp and release objects in a reliable and predictable manner.

      Many end-effectors for executing pick and place operatşons have been investigated for micro assembly.Microgrippers, while not as simple mechanically as single finger manipulators, are capable of handling amuch greater range of microscale parts with greater grasping stability and dexterity. For assembly, a microgripper should have sufficient tweezing range of motion and force, finger surfaces of adequate size and appropriate geometry, low power/voltage, compact size, and ease of manufacture. The actuation technology used is critical factor in determining whether these requirements are met.

      In general , the finger surfaces of a gripper should be on the same scale as the manipulated object (say 10-100 micrometer). This has important consequences for micro-fabrication. If the fingers are adesigned to have movement within the lithographically-patterned plaane, high-aspect-raio micromachining techniques must be used, such as deep reactive ion etching (DRIE) or x ray lithography (LIGA). Sloped sidewalls would be anacceptable for finger surfaces. On the other hand. If actuation force and finger motion are normal to the lithographically-patterned plaen, fingers with adequate area can be manufactured by a variety of conventional micromachining techniques. In this case, finger surface chemistry and morphology may be engineered without difficulty. If thick structures are needed, metal electroplating into photoresist molds may be used. While the sidewalls of these structures may be sloped due to the high aspect ratio, gripper function woul not be compromised since actuation and tweezing motion are out of the lithographically-patterned plane.

      Electrostatic actuators are often advoced for this application, however, their size is quite large in comparison to their limited range of finger motion. Comp drive actuators often require long gripper fingers to amplifiy the comp motion to that needed for finger (~ 100 micrometer). To achieve wide fingers, high-aspect-ratio micromachining must be employed for comp drive designs. As a result, it is difficult to tailor finger surface geometry, morphology, and chemistry as desired for the task of pick-up and release. While surface tailoring is much easier for parallel plate designsi the actuation stroke in this case is far too small for the application.

It is desirable for entire microgripper (including actuator and any motion amplification structures necessary) to be as compact as possible. Ideally, the grippers volume should be comparable to that of the manupilated object, as is the case with the human hand. Compact size enchnces the gripeers ability to perform assembly tasks without encountering physical obstruction from previously assembled components, other manupilators, or fixtures. Compactness also lends itself to greater dexterity for two-fingered manipulators (e.g. through the use of a wrist). Finally, compact size is critical to the visual feedback necassary to coe with the uncertaintities inherent  to microassembly. Microscope optics will have  small field of view, small depth of field, and small working distance (<1 cm). Seperate illumination should be provided for each microscope. The microgripper and micromanipulator should not interfere with the light paths from the  illumination sources to the object, or with those from the object to the microscopes. Small gripper size is critical to avoiding occlusion. Current microgrippers are not compact, largely because of deficiencies in the actuation technologies used. For example, the electrostatic comb microgripper reported in has a tweezing gap of 100 μm. The actuators has dimensions of 2600 μm x 4000 μm x 50 μm. The volumetric utilization (i.e. the ratio of object volume to gripper volume) of this device is therefore less than 0.5%.

      (Control Technologies for Emerging Micro and Nanoscale Systems,Evangelos Eleftheriou, p.214)
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      5)Mechanical Plating(new) (Manufacturing process)

      Mechanical Plating, also known as peen plating or Impact plating, is an adaptation of barrel finishing in which coatings are produced by cold-welding soft, malleable metal powder onto the substrate. Numerous small products are first cleaned and may be given a thin galvanic coating of either copper or tin.They are then placed in a tumbling barrel, along with a water slurry of the metal powder to be plated, glass or ceramic tumbling media, and chemical promoters or accelerators. The media particles peen the metal powder onto the surface, producing uniform-thickness deposits (possibly a bit thinner on edges and thicker in recesses-the opposite of electroplating!). Any metal that can be made into fine powder can be deposited, but the best results are obtained for soft materials, such as cadmium, tin, and zinc. Since the material deposited mechanically, the coatings can be layered or involve mixtures with bulk chemistries that would be chemically impossible due to solubility limits. The fact that the coatings are deposited at room temperature, and in an environment that does not induce hydrogen embrittlement, makes mechanical plating an attractive means of coating hardened steels.

      (Materials and Processes in Manufacturing, E. Paul DeGarmo,p.957)
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