Ufuk Civelek, 030050161, 2nd Week

1) CNC Lathe (Manufacturing Machine)


CNC lathes are widely used in making components with axisymmetric geometry. These are generally machined with 2-axis control. (Z-axis parallel to the spindle and X-axis perpendicular to spindle axis).Some CNC lathes have an additional Y-axis. CNC lathes are usually designed with a slant bed for easy removal of chips, at the same time maintaining the rigidity of a closed box structure. A chip conveyor (either magnetic or mechanical) is usually provided for easy chip disposal.
The control console is located on the front on top side. The spindle is driven usually by
an infinitely variable speed AC drive through a set of V-belts or poly belts. The high
power series motors employed provide almost constant power for a large portion of the speed range. High-speed machines usually have integral rotor spindles. AC servomotors drive the X and Z slides usually. Sliding doors (sometimes automatic) with bulletproof glass windows are provided for safety and visibility of the machining zone. Hydraulic chucks are provided for clamping the workpieces. CNC lathes, being high-speed machines require special highly accurate and well-balanced chucks. Tools are mounted in indexable turrets which can hold 8, 12 or 16 tools.

(CAD/CAM/CIM 3.edition, P. Radhakrishnan, S. Subrahmanyan, V. Raju, p.361)
February 24, 2011


CNC Lathe (new) (Better)


The term ‘turning center’ is rather un popular, but an accurate overall description of a computerized lathe (a CNC lathe) that can be used for a great number of machining operations during a single setup. For example, in addition to the standard lathe operations such as turning and boring, a knurling and even burnishing. It can also be used in different modes, such as chuck work, collet work, barfeeder, orbetween centers. Many other combination also exist.CNC lathes are designed tohold several tools in special turrents, they can hace a milling attachment, indexable chuck, a sub spindle, a tailstock, a steadyrest and many other features not always associated with a conventional lathe design. Lathes with more than four axes are also common. With constant advancesin machine tool technologies, more CNC lathes appear on the market that are designed to do a number of operations in a single setup, many of them traditionaly reserved for a mill or machining center.
Types of CNC Lathes;
Basically, CNC lathes can be categorized by the type of design and the number of axes. The two basic types are the vertical CNC lathe and the horizontal CNC lathe. Of the two, the horizontal type is by far the most common in manufacturing and macine shops. A vertical CNC lathe (incorrectly called a vertical boring mill) is somewhat less common but irreplaceable for a large diameter work. For a CNC programmer, there are no significant differences in the programming approach between the two lathe types.
(CNC programming handbook: a comprehensive guide to practical CNC programming, Peter Smid, p.11)


2) Lapping (Manufacturing)


Lapping is a free abrasive machining process. An abrasive compound in a fluid suspension is applied to the lapping tool, which is called a "lap". The workpiece is placed on top of the lap and moved to cause cutting/material removal at a controlled rate. Lapping is primarily considered to be a three-body abrasive mechanism due to the fact that it uses free abrasive grains that can roll or slide betwwen the workpiece surface and the tool plate, although some grains become embedded in the lap, which would be considered two-body abrasion. A fine abrasion is applied, continuously or at specific intervals, to a work surface to form an abrasive film between the lap and the parts to be lapped or polished.
Each abrasive grain used for lapping has sharp irregular shapes, and when a relative motion is induced and pressure applied, the sharp edges of the grains are forced into the workpiece material. Each loose abrasive particle acts as a microscopic cutting tool that either makes an indentation or causes the material to cut away very small particles.
(Boljanovic V., Metal Shaping Processes: Casting and Molding, Particulate Processing, Deformation Processing, Metal Removal, 2010, pg.411)
March 9, 2011


Lapping (new) (Better)


Lapping is an abrasive surface finishing process where in fine abrasive particles are charged (caused to become embedded) into a soft material, called a lap.The material of the lap may range from cloth to cast iron or copper, but it is always softer than the material to be finished, being only a holder for the hard abrasive particles. Lapping is applied to both metals and nonmetals.
As the charged lap is rubbed against a surface, the abrasive particles in the surface of the lap remove small amounts of material from the surface to be machined. Thus the abrasive does the cutting, and the soft lap is not worn away because the abrasive particles become embedded in its surface instead of moving across it.This action always occurs when two materials rub together in the presence of a fine abrasive: the softer one forms a lap, and the harder one is abraded away.
In lapping,the abrasive is usually carried between the lap and the work surface in some sort of a vehicle, such as grease, oil, or water. The abrasive particles are from 120 grit up to the finest powder sizes. As a result, only very small amounts of metal are removed, usually considerably less than 0.001 in. Because it is such a slow metal removing process, lapping is used only to remove scratch marks left by grinding or honing, or to obtain very flat or smooth surfaces, such as are required oil gage blocks or for liquid-tight seals where high pressures are involved.
Materials of almost any hardness can be lapped. However, it is difficult to lap soft materials because the abrasive tends to become embedded.The most common lap material is fine-grained cast iron. Copper is used quite often and is the common material for lapping diamonds. For lapping hardened metals for metallographic examination cloth laps are used.
(DeGarmo's Materials and Processes in Manufacturing, E. Paul DeGarmo, p.782)



3) Cellular Manufacturing (Manufacturing) (Better)


The machines in a multi-station system with variable routing may be manually operated, semi-automatic, or fully automated. When manually aoperated or semi-automatic, the machine groups arte often called machine cells, and the use of these cells in a factory is called cellular manufacturing.
Cellular manufacturing is an application of group technology in which dissimilar machines or processes have been aggregated into cells, each of which is dedicated to the production of a part, product family, or limited group of families. The typical objectives in cellular manufacturing are similar to those group technology:
To shorten manufacturing lead times by reducing setup, workpart handling, waiting times, and batch sizes.
To reduce work-in-process inventory. Smaller batch sizes and shorter lead rines reduce work-in- process.
To improve quality. this is accomplished by allowing each cell to specialize in producing a smaller number of different parts. This reduces proces variability.
To simplify production scheduling. the similarity among parts in teh family reduces the complexity of production scheduling. Instead of scheduling parts through a sequence of machines in a process-type shop layout, the system simply schedules the parts though the cell.
To reduces setup times. This is accomplished by using group tooling (cutting tools, jigs, and fixtures) that have been designed to process the part famiy, rather than ğart tooling, which is designed for an individual part. this reduces the number of individual tools required as well as the time to change tooling between parts.
(Groover, M.P., Automation, Production Systems and Computer - Integrated Manufacturing, pg.376,518-519, Pearson Education Inc,2008)
(February 15, 2011)


Cellular Manufacturing (new)


We define a cellular manufacturing system as a production system that is decomposed into cells, with cells being able to process several operations per work order. This set of operations per work order reduces the total number of different organizational units that are sequentially involved in producing a product. The result of a good system design is a simple but robust decomposition of the production system into cells. Cells are not oveer-specialized in one product only, as in traditional production lines, but are able to produce a family of parts that require the combining of processes avaible in the cell.
(Design of a period batch control planning system for cellular manufacturing, Jan Riezebos, p.2)


4) Intelligent robot (Automation Machine)

The intelligent robots capable of performing some of the functions and tasks carried out by humans.It is equipped with a variety of sensors with visual and tactile capabilities.Much like humans, the robot observes and evaluates the immediate environment and its proximity to other objects,especially machinery, by perceptionand pattern recognition.It then makes appropriate desicions for the next movement and proceeds accordingly.Because its operation is very complex, powerful computers are required to control this type of robot.
(Kalpakjian S. , Schmid S.R. , Manufacturing Engineering and Technology, p.1169)
February 16, 2011


Intelligent robot (new) (Better)


Industrial robots are becoming increasingly intelligent.In this context. An intelligent robot is one that exhibits behavior that makes it seem intelligent. Some of the characteristics that make a robot appear intelligent include the capacity to:
• interact with its environment
• make decisions when things go wrong during the work cycle
• communicate with humans
• make computations during the motion cycle
•respond to advanced sensor inputs such as machine vision
In addition, robots with intelligent control possess playback capability for both PTP or
continuous path control. These features require (1) a relatively high level of computer control
and (2) an advanced programming language to input the decision-making logic and
other "intelligence" into memory.
(Automation,Production Systems and CIM 2001, Mikell P. Groover, p.219)


5)Flexible Manufacturing Systems (FMS) (Manufacturing Method)


These use computer control of all aspects of manufacturing, the simultaneous incorporation of a number of manufacturing cells, and automated material-handling systems.
(Kalpakjian S. , Schmid S.R. , Manufacturing Engineering and Technology, p. 1147)

February 15, 2011


Flexible Manufacturing Systems (new) (Better)

A flexible manufacturing system (FMS) is a highly automated GT machine cell, consisting of a group of processing workstations (usually CNC machine tools), interconnected by an automated material handling and storage system, and controlled by a distributed computer system. The reason the FMS is called flexible is that it is capable of processing a variety of different part styles simultaneously at the various workstations, and the mix of part styles and quantities of production can be adjusted in response to changing demand patterns. The FMS is most suited for the mid-variety, mid-volume production range
The initials FMS are sometimes used to denote the term flexible machining system.The machining process is presently the largest application area for FMS technology. However, it seems appropriate to interpret FMS in its broader meaning, allowing for a wide range of possible applications beyond machining.
An FMS relies on the principles of group technology. No manufacturing system can be completely flexible. There are limits to the range of parts or products that can be made in an FMS. Accordingly, an FMS is designed to produce parts (or products) within a definedrange of styles. sizes. and processes. In other words. an FMS is capable of producing a single part family or a limited range of part families,
A more appropriate term for an FMS would be flexible automated manufacturing system. The usc of the word "automated" would distinguish this type of production technology from other manufacturing systems that arc flexible but not automated, such as a manned GT machine cell. On the other hand, tile word "flexible" would distinguish it from other manufacturing systems that are highly automated but not flexible, such as a conventional transfer line. However, the existing terminology is well established
(Automation, Production Systems and CIM 2001, Mikell P. Groover ,p.462-463)