5th Week Unanswered Terms

Chvorinov's rule

The total solidification time is the time required for the casting to solidify after pouring. This time is dependent on the size and shape of the casting by an empirical relationship known as Chvorinov's rule which states:

Tts=Cm(V/A)^n

Where Tts: Solidification time, min; V= volume of casting, cm3; A= surface area casting, cm2; n= an exponent usually taken to have value 2 and Cm is mold constant.

Evrim Berk 030060161 5th Week

N-Code: A part program block usually begins with an "N" word. The N word specifies the sequence number. It is used to identify the block within the program. It is especially useful for program editing. For example, when the format is "4", a proper sequence number would be N0010. It is a good practice to program N values in increments of 10 or greater. This allows additional blocks to be inserted between two existing blocks.

(Computer Aided Drawing 2nd Edition, Chang T.C., Wysk R.A., Prentice Hall, 1998, Page:365)

Articulated Robots: An articulated robot has three rotational axes connecting three rigid links and a base. An articulated robot is frequently called anthropomorphic arm because it closely resembles a human arm. The first joint above the base is referred as the shoulder. The shoulder joint is connected to the upper arm, which is connected at the elbow joint. Articulated robots are suitable for a wide variety of industrial tasks, ranging from welding to assembly. Similar to other types of robots, the X, Y and Z coordinates of an articulated robot can be obtained from the joint variables using the following equations.β

X=[l1cosβ + l2cos(β+ɣ)]cosα

Y=[l1cosβ + l2cos(β+ɣ)]sinα

Z=l1sinβ + l2sin(β+ɣ)

where α, β, ɣ are joint variablesi and l1 and l2 are the lengths of the lower arm and upper arm, respectively.

(Computer Aided Drawing 2nd Edition, Chang T.C., Wysk R.A., Prentice Hall, 1998, Page:428)

Axiomathic Approach: The axiomathic Approach is the result of a scientific search for the basic principles of design by Nam P. Suh of the Massachusets Institue of Technology. The complete ddetails of this approach is the basis of the following presentation.

The axiomathic approach is based on the assumption that there exists a fundamental set of principles that determines good design practice. Phrased differently, there should exist common factors in all good designs. These factors are fundamentally principles of design can be applied to all design situations, like the natural laws in natural science problems. These principles are the basis for the solution and process optimization, using emprical knowledge and mathematical tools. This method is based on two fundamental principles, or axiomsi that it followed adequently result in good design. The Independence Axiom and The Information Axiom.

(Computer Aided Drawing 2nd Edition, Chang T.C., Wysk R.A., Prentice Hall, 1998, Pages: 605-606)

Hitachi Assembly Method: This method was originally developed in Japan in 1976 by Hitachi. This method is an effective tool for quantitatively eveluating the product-design quality for assembly producibility at early design stages. In the conventional product-design procedure, redesigning required so much time that products with poor producibility characteristics were manufactured. To counteract this, the HAM approach to product design includes two feedback loops to check for good producibility characteristics: one at the conceptual designing stage, and the other one at the detail designing stage. This procedure results in less product development time and in a more economical solution to the design problem.

For its application HAM requires information available at the early stages of the product-design process. Conceptual drawings, for example, could be used to carry out this analysis.

(Computer Aided Drawing 2nd Edition, Chang T.C., Wysk R.A., Prentice Hall, 1998, Pages: 603-604)

ÖMER TAYLAN BOYA 030070099 5th WEEK

First in first out (FIFO) (time 09:20 am 13.03.2011)

In many storage systems, stock is rotated on a first-in-first-out (FIFO) basis, which
implies that random access to every single load in the system may not be necessary. Hence, the right level of selectivity would ensure that, given a set of loads of the same type, only the oldest load needs to be easily accessible. This concept has, in fact, led to pallet flow racks, where loads are stored in lanes and each lane holds multiple loads of the same type. At any given time, only the loads in the front of each lane (which, by definition, are the oldest loads in each lane) are easily accessible. Pallet flow racks increase storage density by minimizing the space required by aisles. However, some space is wasted within each lane because the number of loads in a lane varies over time and, at any given instant, some lanes may be full while others are nearly empty.

(Gavriel Salvendy, Handbook of Industrial Engineering: Technology and Operations Management, page 1251)

Part Familiy Formation (time 11:30 13.03.2011)

During the preparatory stage, existing components are coded, classified, and later grouped into
families (Figure 19). The part family formation can be performed in several ways. Families can be formed based on geometric shapes or process similarities. Several methods can be used to form these groupings. A simple approach would be to compare the similarity of the part’s code with other part codes. Since similar parts will have similar code characteristics, a logic that compares part of the code or the entire code can be used to determine similarity between parts.

((Gavriel Salvendy, Handbook of Industrial Engineering: Technology and Operations Management, page 476)

Gantt Chart (time 09:55 am 13.03.2011)

Gantt Chart. The Gantt chart was developed by Henry Gantt about 1917 as a means for
scheduling work in a job shop. It has become the most easily understood portrayal of a scheduled plan for a variety of types of work (see Fig. 17.9.5).While it was used extensively prior to computer methods for scheduling projects, it was often demeaned by the comment, “It conceals more than it reveals.” Manual means for preparing Gantt charts were so time-consuming and expensive as to be practically “cast in bronze.” As a result, the tendency was to delay redrawing them until the project was well off schedule.

(Maynard's Industrial Engineering Handbook, McGrawHill, unit 17.190, page 2521)

Solutin heat treatment process (time 11:05 am 13.03.2011)

In the solution heat treatment process alloy is first heated above the solvus temperature and held until a homogeneous solid solution a(alfa) is produced. This step dissolves the 0(teta) precipitate and reduces any segregation present in the original alloy.

(Donald R. Askeland, The Science and Engineering of Materials, page 323)

Olcay Türkoğlu (5th week)

1 Hydraulic automation

2 Solenoid operation

3 Deceleration valve

4 Sequencing Actuators

5 Hydraulic interlocks

6 Borazon Tips

7 Rake angle

8 Obliquity angle

9 Approach angle

10 End cutting angle

Burcu Atay, 140060029, 5th week

Open Mold

The distinguishing feature of this family of FRP( fiber-reinforced polymer composites) shaping processes is its use of a single positive or negative mold surface to produce laminated FRP structures. Other names for open mold processes include contact lamination and contact molding. The starting materials (resins, fibers, mats, and woven rovings) are applied to the mold in layers, builging up to the desired thickness. This is followed by curing and part removal. Common resinds are unsaturated polyesters and epoxies, using fiberglass as the reinforcement. The moldings are usually large( e.g., boat hulls). The advantage of using an open mold is that the mold costs mych less than if two matching molds wew used. The disadvantage is that only the part surface in contact with the mold surface is finished; the other side is rough. For the best possible part surface on the finished side, the mold itself must be very smooth.

There are several important open mold FRP processes. The differences are in the methods of applying the laminations to the mold, alternative curing techniques, and other variations. The family of open molf processes for shaping fiber-reinforced plastics: (1) hand lay-up, (2) spray-up, (3) automated tape – laying machines, and (4) bag molding. We treat hand lay-up as the base process and the others as modifications and refinements.

(Groover, M.P., Fundamentals of modern manufacturing: materials, processes, and systems, 4th Edition, pg.331-332)

edit:

Open sand molds suitable for casting large metal plates, especially aluminium plates for builfing facades are prepared by using a large roller bearing a model and rolling spaced guides to level a bed of moldable substance therebetween and simultaneously impressing the molding pit in the bed.

(United States Patent US3812902, Apparatus for preparing open sand molds suitable for casting large metal plates, 1974, pg.1)

Intelligent Control

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 capacities to interact with its environment, make decisions when things go wrong during the work cycle, communicate with humans, make computations during the motion cycle, and respond to advanced sensor inputs such as machine vision.

In addition, robots with intelligent control possess playback capability for both PTP(point-to-point) or continuous path control. These features require (1) relatively high level of computer control and (2) an advanced programming language to input the decision-making logic and other “intelligence” into memory.

(Groover, M.P., Automation, Production Systems and Computer - Integrated Manufacturing, pg.222, Pearson Education Inc,2008)

Fly Cutter

For drilling large holes in pipe or sheet metal, twist drills are not suitable because of the drill tends to dig into the work or the hole is too large to be cut by a standard-size drill. Large holes are cut in thin metal by a hole cutter. Saw- type cutters of this design can be obtained in a wide range of sizes. For very large holes in thin metal a fly cutter is used. Such a cutter consists of tool bits held in a horizontal holder that can accommodate a range of diameters. Both cutters cut in the same path but one is set slightly below the other.

(Amstead, B.H., Ostwald P.F., Begeman, M.L., Manufacturing Processes, 8th Edition, John Wiley & SOns, Inc, pg.510)

Tweak Features

Tweak features deform or alter (“tweak”) the surface of a part. For example, the draft feature adds a draft angle to a surface, or to a series of selected planar surfaces. The Radius Dome option allows a user to create a dome feature. Other Tweak features may include section dome local push ear, offset and draft offset, replace, lip, patch, toridal and spinal bends, and free form.

(Xun Xu, Integrating Advanced Computer-Aided Design, Manufacturing, and Numerical Control: Principles and Implementations, pg.152)

Kayra Ermutlu-030060081 (5th Week)

Foundry

A foundry is a factory equipped for making molds, melting and handling metal in molten form, performing the casting process, and cleaning the finished casting.

(Groover M.P., Fundamentals of Modern Manufacturing:Materials, Processes and Systems, pg.207, Kayra Ermutlu)

Roll Forming

Roll forming (also called contour roll forming) is a continuous bending process in which opposing rolls are used to produce long sections of formed shapes from coil or strip stock. Several pairs of rolls are usually required to progressively accomplish the bending of the stock into the desired shape.

Products made by roll forming include channels, gutters, matel siding sections (for homes), pipes and tubing with seams and various structural sections. Although roll forming has the general appearance of a rolling operation (and the tooling certainly looks similar), the difference is that roll forming involves bending rather than compressing the work.

(Groover M.P., fundamentals of Modern Manufacturing: Materials, Processes and Systems, pg. 472, Kayra Ermutlu)

Low-Pressure Die-Casting

Low pressure die casting has been lately developed to enable produciton of castings that are flawless, have very thin sections and register a yield approaching 100% even in metals such as aluminium and magnesium. The mould, which is made in metal (usually cast iron), is filled by upward displacement of molten metal from a sealed melting pot or bath. This dispalcement is effected by applying relatively low pressure of dry air (0.5~1.0 kg*(mm^-2) on the surface of the molten metal in the bath. The pressure causes the metal to rise through a central cast iron tube and move into the die cavity. The dies are provided ample venting to allow the escape of air. The pressure is maintained till the metal is solidified: then it is released enabling the excess liquid metal to drain down the connecting tube back into the bath. Since the system of upward filling requires no runners and risers, there is hardly any wastageof metal. As positive pressure is maintained to force the metal to fill recesses and cavities, casting with excellent surface quality, finish and soundness are produces. Low pressure on the metal completely eliminates turbulence and air aspiration. Cores, if required, can be used in the dies: they may be of sand or shell.

(Jain P.L., Principles of Foundry Technology, pg.170, Kayra Ermutlu)

Ultrasonic Welding

Ultrasonic welding is an industrial technique whereby high frequency ultrasonic acoustic vibrations are locally applied to work piece that are held together under pressure to create a solid state weld. In ultrasonic welding there are no connective bolts, nails, soldering materials or adhesives necessary to bind the materials together. This process is speacially used for plastics and for joining dissimilar metals like thin copper, aluminium, nickel etc. used in fuel cells.

Ultrasonic welding is not due to heating but occurs due to high pressure dispersion of surface oxides and local motion of material. Vibrations are introduces along the joint being welded. Common frequencies used in welding of plastics are from 15 kHz to 70 kHz.

The basic components of ultrasonic welding processes include the following:

1. A pressure to put two parts of material to be assembled under pressure.
2. An anvil where the parts are placed and allowing high frequency vibrations to be directed to interfeces.
3. An ultrasonic generator to produce frequencies of 15 kHz to 70 kHz.
4. A converter that conversts the electrical signal into mechanical vibrations.
5. Sonotrade that applies mechanical vibrations to the parts to be welded.
6. A controller that controls the movement of the press and the delivery of ultrasonic energy.

Benefits of ultrasonic welding:

• Very neat weld seams: As no additional adhesive or parts are needed, ultrasonic welding joints created are extremely neat and visually attractive.
• High level quality: As all welding parts of the operations are automated, each part produced will be of high quality.
• Low cycle times: The actual time it takes a part to be welded is typically less than one second. Thus large batches can be produced in a short span of time.

(Rajagopal K., Textbook of Engineering Physics-Part I, pg.16-17, Kayra Ermutlu)

A. Selim PARLAKYİĞİT - 5th Week

1. Hydroforming
2. Roll Forming
3. Orbital Cold Forging
4. Oxyfuel Gas Cutting
5. New-Design Control
6. Incoming Material Control
7. Line Balancing
8. Repetitive Design
9. Work Sampling
10.Baka-Yoke

Onur OZAYDIN___5th Week

1. Manuel Part Programming

2. Computer-Assisted Part Programming

3. CAD/CAM- Assisted Part Programming

4. Manuel Data Input (MDI)

5. Limited Sequence Control (about robots)

6. Intelligent Control (about robots)

7. Metrology

8. Mechanical Gages

9. Electronic Gages

10. Ring Gages

503101307 Onur OZAYDIN

Ozlem Salman (5th week)

1 Booleon operation
2Pultrasion
3Brazing
4Lapping
5Tail stock
6 End mill
7 Face mill
8 Slab mill
9 Fly cutter
10 Ball nose cutter