Industrial Communication Skills Past Paper PDF

Unit A-10 • Fundamental Industrial Communication Skills Objective 1 Create sketches using centre lines and dimensioning. Centre Lines During the operation of a plant, a special repair part may be required which must be made to certain specifications. With a sketch, all the necessary information, s...

Unit A-10 • Fundamental Industrial Communication Skills Objective 1 Create sketches using centre lines and dimensioning. Centre Lines During the operation of a plant, a special repair part may be required which must be made to certain specifications. With a sketch, all the necessary information, such as the shape and size, required to make the part can be conveyed in a few lines. Without a sketch, it may be more difficult to explain the desired result, either verbally or in writing. This will create a greater possibility of error. Some hints on sketching freehand are included in this chapter. However, it may be just as quick to use a few simple drawing instruments which do a much better job. These inexpensive instruments are all that are required: • Two triangles (60° and 45°) • Scale or ruler • Compasses • Pencil • Eraser The proper way to make a sketch can be summed up in the following simple instructions: 1. Make sketches large. It is easier to draw on a large scale, and it shows details more clearly. 2. Begin with the centre lines and take all necessary measurements from them. 3. Make the sketch in proper proportion so that it looks like the object it is supposed to represent. 4. Lines needed only for construction purposes, such as centre lines, should be drawn lightly, but heavier lines should be used to outline the object being drawn. 5. Print the name of the component beneath the sketch, and put the names of the principal parts on the sketch. a) Do not complicate a sketch with unnecessary detail. b) Show only what is asked for, but show that on a large scale. All sketches are made up of arcs and lines, so it is necessary to be able to draw circles and straight lines. To sketch a straight line: 1. Sketch the endpoints of the line as dots or small crosses. 2. Place the pencil on the starting endpoint. 3. Keep an eye on the terminal endpoint, and use a smooth continuous stroke to draw the line between the endpoints. 1-4 4th Class Edition 3 • Part A Energy Plant Sketching • Chapter 1 Figure 1 – Drawing Lines To sketch a circle or arc: 1. Draw light horizontal and vertical lines that cross at the center of the circle. 2. Lightly mark the radius of the circle on each line. 3. Connect the radius marks with a curved line to form a circle or arc, as necessary. Figure 2 – Drawing a Circle 4. Alternatively, a lightly sketched square can be used as an enclosure. First, mark the midpoints on the sides. Then draw light arcs tangent to the sides of the square. Finally darken in the circle. Figure 3 – Drawing a Circle Note: It is generally easier to sketch a curve (circle, arc, etc.) on the concave side of the arc as the hand naturally pivots in this way. 4th Class Edition 3 • Part A 1-5 Unit A-10 • Fundamental Industrial Communication Skills A more complex sketch by drawing the foundation or centre lines is illustrated in Figure 4. This is a sketch of a knuckle joint. It has three preliminary steps or stages which illustrate how to easily make a freehand sketch of the right size and proportions. Figure 4 – Sketching a Knuckle Joint To make the sketch in Figure 4: 1. Draw the horizontal centre line. Then draw four horizontal parallel lines. Space the lines so that the inner part of the joint is somewhat wider than the outer sections of the forked member. Next, draw a vertical centre line for the pin. The sketch should now look like the one in the upper left hand corner of Figure 4. Draw the horizontal centre line and then four horizontal parallel lines spaced so that the inner part of the joint is somewhat wider than the outer sections of the forked member. Next, draw a vertical centre line for the pin. The sketch is now as represented in the upper left hand corner of the illustration. 2. For the second stage, shown in the upper right image, draw the lines spaced to suit the pin diameter. Except at the top, these lines represent a part of the pin that is concealed. They may be drawn in lightly, and dotted in afterwards. Draw vertical lines to locate the end of the fork. 3. In the third stage, shown in the lower left of the image, add the straight lines as shown to complete the basic shape. 4. In stage four, shown in the bottom right of the image, fill in the hidden features. Use dashed lines for the pin, and arcs for any curved elements. To give a 3D dimensional view, use a cross-hatch to indicate the shaft. The result is a proportional sketch. All the prominent parts are clearly drawn, and it is ready for dimensioning. 1-6 4th Class Edition 3 • Part A Energy Plant Sketching • Chapter 1 Dimensioning So far, the sketch from Figure 4 only shows a shape. To be a useful working tool, it must be given size. Figure 5 shows an example of dimensioning on a simple sketch. The points at which the measurements are to be taken are brought out as “extension lines”. The dimension line then extends the full distance between these extension lines, with a break for the dimension number. Figure 5 – Typical Dimensions on a Working Drawing 5 7/8 Extension Lines 3 1¼ 3 The Dimension Number The Dimension Line For all sketching, always draw the most important lines first. They are the ones that establish the main proportions of the sketch and enable proportioning to be done. The practical application of this principle of sketching will be illustrated by the different examples that follow. 4th Class Edition 3 • Part A 1-7