MÜGE BAŞARAN 030090704 2nd week

1- Cutting speed / (about machining)

Previous Definition:

Machining is not just one process;it is a group of processes.The common feature is the use of cutting tool to form a chip that is removed from the workpart.To perform the operation ,relative motion is required between the tool and work.This relative motion is achived in most machinig operations by means of primary motion,called the cutting speed.The shape of the tool and its penetration into the work surface, combined with this motion, produces the desired shape of the resulting work surface.

(P.Groover ,Fundamentals of Modern Manufacturing third edition, page 483)
Current Definition:


Cutting speed is measured by the maximum speed of which a tool can provide satisfactory performance for a specified conditions. Machinability is defined by the relative cuting speed for a given tool life while cutting some material, compared to a standart material cut with same tool material. As shown in Figure 21-24, tool life curves are used to develop machinability ratings. For example , in steels, the material choosen for the standart material was B1112 steel, which has a tool life of 60 min at a cutting speed of 100 sfpm.  Material X has a 70% rating, which implies that steel X has a cutting speed of 70% of B1112 for equal tool life. Note that this definition assumes that the tool fails when machining material X by whatever mechanism dominated the tool failure when machining the B1112. There is no guarantee that this will be the case. ISO standard 3685 has machinability index numbers based on 30 min of tool life with flank wear of 0.33mm.

(Degarmo's Materials and Processes in Manufacturing , E. Paul DeGarmo,J. T. Black,Ronald A. Kohser, pg. 598)

(Mathematics for Machine Technology, Robert D. Smith,John C. Peterson , pg. 260)

2- Manipulator / (about Design and control of industrial robots)

Previous Definition:

It is a robot component that also called arm and wrist, the manipulator is a mechanical unit that provides motions(trajectories) similar to those of a human arm and hand.The end of the wrist can reach a point in space having a specific set of coordinates and in a specific orientation.Most robots have six rotational joints.Seven degrees of freedom or redundant robots for special applications also are available.

(Kalpakjian S., Schmid S.R.,Manufacturing engineering and technology, 1166)
Current Definition:

The most generally accepted definition of a robot is a reprogrammable, multifunction manipulator designed to move material, parts, tools, or specialized devices through variable programmed motions to perform a variety of tasks. Robots can be floor-standing, benchtop, or mobile.

Robots are classified in ways that relate to the characteristics of their control systems, manipulator or arm geometry, and modes of operation. The size of the manipulator or arm influences accessibility to the assigned floor space. Movement is a key consideration in choosing a robot. The robot must be able to reach all the parts or tools needed for its application. Thus the robot’s working range or envelope is a critical factor in determining robot size.

There are four principal geometries for robot manipulators: (1) articulated, revolute, or jointed-arm (Figs. 2 and 3); (2) polar coordinate (Fig. 4); (3) Cartesian (Fig. 5); and (4) cylindrical (Fig. 6). However, there are many variations possible on these basic designs, including vertically jointed (Fig. 7), horizontally jointed, and gantry or overhead-configured.

(Mechanisms and Mechanical Devics Sourcebook, Third edition, Neil Sclater, Nicholas P. Chironis, pg.34-37)

3-Design Requirements (about design)
Previous Definition:

One of the first steps in airplane design is the establishment of design requirements and objectives. These are used to formally document the project goals, ensure that the final design meets the requirements, and to aid in future product development. The specific DR&O's are based on customer requirements, certification requirements, and company policy (often in the form of a design standards manual). They have evolved from rather simple letters to very complex system engineering documents.

(Kroo, I., “Aircraft Design: Synthesis and Analysis”)

Current Definition:

The starting point of a design is a market need or a new idea; the end point is the full specification of a product that fills the need or embodies the idea. A need must be identified before it can be met. It is essential to define the need precisely—that is, to formulate a need statement, often in this form: “A device is required to perform task X,” expressed as a set of design requirements. Writers on design emphasize that the need statement should be solution-neutral (that is, it should not imply how the task will be performed) to avoid narrow thinking constrained by preconceptions. Between the need statement and the product specification lie the stages shown in Figure 2.1: concept, embodiment, and detailed design, explained in a moment.

The design proceeds by developing concepts to perform the functions in the function structure, each based on a working principle. At this, the conceptual design stage, all options are open: The designer considers alternative concepts and the ways in which these might be separated or combined. The next stage, embodiment, takes the promising concepts and seeks to analyze their operation at an approximate level. This involves sizing the components and selecting materials that will perform properly in the ranges of stress, temperature, and environment suggested by the design requirements, examining the implications for performance and cost. The embodiment stage ends with a feasible layout, which is then passed to the detailed design stage. Here specifications for each component are drawn up. Critical components may be subjected to precise mechanical or thermal analysis. Optimization methods are applied to components and groups of components to maximize performance. A final choice of geometry and material is made and the methods of production are analyzed and costed. The stage ends with a detailed production specification.

(Material Selectiom in Mechanical Design 4th edition , Michael F. Ashby , pg. 16,17,18)

4- Batch Production (about manufacturing menagement)
Previous Definition:

Production rate is defined as the number of the parts produced per unit time, such as per day, per month or per year. The approximate and generally accepted ranges are given at the related tables in books or standarts. Job shops typically produce small quantities per year using various stardard general-purpose machine tools or machinig centers. Batch production is the kind of a production which usually involves lot sizes between 100 and 5000. It utilizes machinery similar to that used for small-batch production but with specially designed for higher prouctivity.

(Kalpakjian S., Schmid S.R., Manufacturing engineering and technology, pg 1149)

Current Definition:

Batch production is distinguished by its intermit-tent manufacturing: a particular product is made in lots or batches that may range in size from a very few to a very many. The key feature is that these items are not made constantly hut must in-stead lit in with the production or other products. Batch production may exist as regularly scheduled production, for example, when; a month’s  sales requirements are made once each month. Batches also may be produced irregularly, as when demand is highly variable. Batch production is most frequently used when the general production capacity available greatly exceeds the demand for any specific product hut the production of a number of different products fills the production capacity. In these cases, a specialized or dedicated process to make one product is generally not economically viable. There may be technical aspects of the production process that limit the size of batches.

Batch size:

A batch is a quantity either in production or scheduled to be produced. The concept of batch size is best defined in terms of two different concepts, the process batch and the transfer batch. A process batch is the quantity of a product processed at a work center before that work center is reset to produce a different product. A transfer batch is the quantity of units that move from one work center to the next. The transfer batch size need not, and in most cases, should not be equal to the process batch size: process hatch can be equal or greater than transfer batch. In synchronized or lean manufacturing systems, the transfer batch size generally should be kept as small as possible in order to ensure a smooth and rapid flow of materials. The process batch size should be determined by the requirements of the system and should be allowed to be variable as needed over time. At bottleneck work centers, especially those with significant setup times, the small transfer hatches should be used with relatively large, economical process batches.

(Encyclopedia of production and manufacturing management , Paul M. Swamidass, pg.60,61)

5- Compound Features (about design for CAM)

Previous Definition:

A compound feature is a combination of single features. Compound features handle the situation in which a large single feature contains certain smaller attached single features. On the other hand, from the manufacturing point of view, compound features can be defined as features that intersect with each other. Therefore, the machining sequence may or may not affect the machining of the other feature.

(Emad Abouel Nasr,Ali K. Kamrani, Computer-Based Design and Manufacturing An Information-Based Approach, pg.189)

NOT: 5. Tanımımla ilgili araştırmayı yaparken birönceki arkadaşın bulduğu şle aynı kştaptan bulduğumu bilmiyordum. Fakat o kitaba ulaşmak için baya çaba sarfettiğimden tanımı hazırlamış olduğum bu şekilde koymak istiyorum. Çünkü bulunabilen en iyi tanım bahsi geçen kitapta yer almaktadır.

Current definition:

A compound feature is a combination of single features. Compound features handle the situation in which a large single feature contains certain smaller attached single features. On the other hand, from the manufacturing point of view, compound features can be defined as features that intersect with each other. Therefore, the machining sequence may or may not affect the machining of the other feature. For example, as shown in Figure 8-8, the hole through feature intersects the slot blind feature. If the hole through feature has a diameter larger than the width of the slot blind feature, machining the slot blind feature first and the hole through feature second will lead to a problem in the drilling operation. Hence, recognition of the compound features will play an important key role in the downstream CAM applications.

(Computer-based design and manufacturing: an information-based approach, Emad Abouel Nasr,Ali K. Kamran, pg. 189,190)