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ENGINEERING DRAWING

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TITLE

GEOMETRIC DIMENSIONING AND TOLERANCING (GDT)

The dimensioning and tolerance, is the standard dimensioning for engineering drawings, the details of dimensioning, dimensioning techniques and the standard tolerance for engineering drawings.

ORTHOGRAPHIC PROJECTION

The view in orthographic projection is the types of orthographic projection, dimension orthographic projection drawing according to standard and the relationship between dimensional drawing and working drawing.

ISOMETRIC

The relationship between an orthographic projection and object in3-D form, the differences and similarities between orthographic projection and isometric view, draw isometric view according to the reference point and arrow direction on an orthographic drawing and dimension isometric view according to standard.

PARALLEL AND RADIAL LINES DEVELOPMENTS

Apply the various methods of developments, the concept of determining the true length and construct the development using the methods given.

AUXILIARY PROJECTION

The relationship between orthographic and auxiliary projection, the various types of view in auxiliary projection, auxiliary projection drawing according to standard and differentiate between dimensions and drawing.

THEORY

GEOMETRIC DIMENSION AND TOLERANCE

Geometric tolerance as shown in a design drawing is a means of communication

between the manufacturer and designer. When judging product quality, whether

or not the geometric tolerance conforms with the specification on the design

drawing is an important indicator. Prediction refers to the assessment and

anticipation of the geometric tolerance which will be achieved. Prediction has

become important in modern management science. Because of the need for an

objective environment, prediction is emerging as a science for exploring and

searching for the specification conformance of the product. Among the existing

prediction methods, the time series method is widely adopted. The time series

method assumes the past historical data of the analyses subject (time series) to

be stationary and requires a statistical distribution. In prediction analysis using a

random statistical method, a large quantity of historical data is required. The data

must possess a standard statistical distribution in order to make an accurate

assessment and prediction of the required parameters. Other methods such as

artificial intelligence, expert systems and neural networks may not need too many

assumptions. However, in applications, these methods require the system

operators to provide an empirical algorithm for the actual prediction values. A

large quantity of historical data is also needed to obtain better prediction values.

In this paper, the grey prediction GM (1,1) model was used to inspect circularity

geometric tolerance to determine whether products conform to the circularity

geometric tolerance on the design drawing. For the purpose of quality control,

geometric tolerance is often measured after the products are finished. However,

this approach usually wastes at least one product. If the characteristics of speedy

calculation and the small amount of historical data required in the grey theory can

be applied.

ORTHOGRAPIC PROJECTION

Orthographic projection is a system that is used in engineering to describe the

shape and dimensions of the multifaceted engineering equipment. It is a system

where many view the entire shape of the object can be clearly shown without

affecting the actual dimensions of the object. In many industrial complex shaped

objects, which require more than one view to show the shape of the object.

Pictorial painting or drawing pictures (three dimensional) often used by people -

people who do not understand the technical, but for those who are directly

involved in the technical, the most suitable painting is painting a variety of forms

(multitier projection), also known as orthographic drawings (orthographic

projection).

ISOMETRICIsometric drawings are a type of pictorial drawings that show the three principal dimensions of an object in one view. The principal dimensions are the limits of size for the object along the three principal directions. Pictorial drawings consist of visible object faces and the features lying on the faces with the internal features of the object largely hidden from view. They tend to present images of objects in a form that mimics what the human eye would see naturally. Pictorial drawings are easy to understand since the images shown bear resemblance to the real or imagined object. Non-technical personnel can interpret them because they are generally easy to understand. Pictorial drawings are excellent starting point in visualization and design and are often used to supplement multiview drawings. Hidden lines are usually omitted in pictorial drawings, except where they aid clarity. An isometric drawing is one of three types of axonometric drawings they are created based on parallel projection technique. The other two types of axonometric drawings are diametric and trimetric drawings. In isometric drawings, the three principal axes make equal angles with the image plane. In diametric drawing, two of the three principal axes make equal angles with the image plane while in trimetric drawing; the three principal axes make different angles with the image plane. Isometric drawings are the most popular.

PARALLEL AND RADIAL LINES DEVELOPMENTS

PARALLEL LINE DEVELOPMENT

Parallel line development is based upon the fact that a line that is parallel to

another line is an equal distance horn that line at all points. Objects that have

opposite lines parallel to each other or that have the same cross sectional shape

throughout their length are developed by this method To gain a clear

understanding of the parallel line method, we will develop, step by step, a layout

of a truncated cylinder such as one half of a two-piece 0 degree elbow.

RADIAL LINE DEVELOPMENTThe radial line method of pattern development is used to develop patterns of objects that have a tapering form with lines converging at a common center. The radial line method is similar in some respects to the parallel line method. Evenly spaced reference lines are necessary in both of these methods. But, in parallel line development, the reference lines are parallel—like a picket fence. In radial line development, the reference lines radiate from the APEX of a cone—like the spokes of a wheel. The reference lines in parallel line development project horizontally. In radial line development, the reference lines are transferred from the front view to the development with the dividers. Developing a pattern for the frustum of a right cone is a typical practice project that will help you get the feel of the radial line method. You are familiar with the shape of a cone. A right cone is one that, if set big-side-down on a flat surface, would stand straight up. In other words, a centerline drawn from the point, or vertex, to the base line would form right angles with that line. The frustum of a cone is that part that remains after the point, or top, has been removed.

AUXILIARY PROJECTIONAuxiliary views are a type of orthographic projection used to determine the true size and shape of inclined and oblique surfaces of objects. Normally, auxiliary views are projected from existing principal views. However, auxiliary views can also be drawn first and then used to create a principal view. This is done when a true measurement can only be obtained by an auxiliary view and that measurement is needed in order to create a principal view. This technique is called reverse construction. Any number of auxiliary views of an object can be created. Successive auxiliary views can be created by projecting from an existing auxiliary view.

DISCUSSION

THE APPLICATION OF DRAWING IN THE PRODUCTION INDUSTRY

One seldom-discussed but important aspect of inventing success is having good technical drawings. A technical drawing varies from a simple sketch or layman’s drawing in a notebook. While these are helpful in the early stages of conceptualizing, a technical drawing is a much more detailed visual representation intended to “concisely and clearly communicate all needed specifications to transform an idea into physical form”, according to Wikipedia.

This becomes important when it comes time to develop a working prototype of your invention, and especially when it comes time to mass-produce it. The crude “notebook” drawings you sketched up yourself won’t be accepted or usable by a manufacturer. Without detailed technical drawings that a manufacturer can take into his hands and understand, you most likely will experience serious delays and costly errors. So let’s explore in more detail what technical drawings are, how they will benefit you, and how you can attain them.

As noted, the main people who will be creating and using technical drawings of your invention are engineers. The main difference between technical drawings and other drawings is the degree of standardization. Rather than simply sketching your invention, an engineer drafting a technical drawing will meticulously draw it out in accordance with industry-wide standards for everything from layout, line thickness, symbols, descriptive geometry, text size, notation, dimensioning and view projections. This means that any similarly qualified engineer can look at your technical drawing and understand exactly what it represents with minimal explanation from you.

THE IMPORTANT OF GEOMETRIC DIMENSION AND TOLERANCE IN ENGINEERING DRAWING

Practice interpreting GD&T on industrial drawings can help you interpret GD&T on the job. ETI's Geometric Dimensioning and Tolerance Workbook, by Alex Krulikowski provides hours of practice applying GD&T skills to engineering drawings.

The 204-page workbook can be used in the classroom as reinforcement to a Fundamentals of GD&T course. It can also be used after the class is complete, because interpreting actual drawings will give students extra practice applying concepts taught in the classroom.

The GD&T enhances student skills by providing practice on each concept from our fundamentals of GD&T course. Questions refer to content in the Fundamentals of GD&T textbook, and are designed to let you gain practice using GD&T in the same manner you would on the job. Drawings include adaptors, retainers, shafts, plates, pulleys, housings, and more.

REFERENCE

http://en.wikipedia.org/wiki/Isometric_projection

http://en.wikipedia.org/wiki/Engineering_drawing#Auxiliary_projection

http://schools.spsd.sk.ca/waltermurray/library/Subjects/Drafting/Dr%2010%20new/Development%20Notes.pdf

http://highered.mcgraw-hill.com/sites/dl/free/0072864583/132262/FGC_4e_Out_ch6.pdf

http://www.amazon.com/Geometric-Dimensioning-Tolerancing-Workbook-Engineering/dp/0924520388

http://www.ideabuyer.com/news/the-importance-of-technical-drawings/

Drawing in mathematicOrthographic and plan and elevation view enlargement and narrowing of the Incarnation addition, Lines and Planes Scale Three Dimensions Isometric and Orthographic locus, Length, Area and Volume, Plane Trigonometry and Circle Geometry Fractions, Ratio, Average, Scale and Scale and Dividing Lines commonality.

New curriculum goal for Secondary Schools (KBSM) for mathematics is to develop logical thinking, analytical, systematic and critical thinking, problem solving skills and the ability to use mathematical knowledge so that an individual can function effectively in everyday life. In line with the above statement then the teachers.

APPLICATIONS ENGINEERING DRAWING CONCEPTS AND METHODS IN MATHEMATICS

Is must use the concepts and methods in teaching mathematics LK related, because of the direct relationship between the two subjects. For example, in the construction using orthographic projection point. According to Klausmeier (1974), the concept is a mental construction of the individual to excel at a higher level. Based on the statements Klausmeier, the concept is seen as experience and have a very important relationship between the external input and real behavior.

It is clear that the integrated teaching is so important and necessary for a good concept “penanggapan” (Abu Bakar, 1991). By the teaching and learning of mathematics and LK must be integrated in terms of concepts and methods, especially in the technical school has adequate facilities. For example, the solution for the plan and elevation of topics in mathematics will be more effective if teachers continue to embrace the concept of angle projection as practiced in LK.

LINEAR AND RADIAL DIMENSIONSBoth linear and radial dimensions were described in detail. A discussion of their use, however, was very limited. This section will briefly address situations where each type of dimension would be used on an electronics drawing. If a concept or command is unfamiliar, you should consults the main text for more information so that each of these examples is understood.

LINEAR DIMENSIONS

Linear dimensions are used to measure distance along the horizontal or vertical axis. The majority of all mechanical dimensions will be linear. Look though the drawings presented in this workbook. Notice that almost all dimensions are horizontal and vertical.

ALIGNED DIMENSIONS

Aligned dimensions are any dimensions that are not vertical or horizontal. Aligned dimensions are very useful when auxiliary views need to be dimensions.

RADIAL DIMENSIONS

To create radial dimensions use the radius and diameter buttons located on the dimensions toolbar. While the radius button is great for dimensioning the radius or arcs, dimensions created with the dimensions button does not conform to normal ASME standards. To dimensions diameters, use the LEADER command and be sure to include the string at the beginning of the text so that the diameter symbol will be included. An example of a proper diameter dimension using the LEADER command is shown.