Lesson Notes By Weeks and Term - Senior Secondary 2

TERM – 1^ST TERM

WEEK SIX - EIGHT

Class: Senior Secondary School 2

Age: 16 years

Duration: 40 minutes of 5 periods each

Date:

Subject: Technical Drawing

Topic: SURFACE DEVELOPMENT, INTERPENETRATION

SPECIFIC OBJECTIVES: At the end of the lesson, pupils should be able to

I.) Define interpenetration                  

II.) Construct the interpenetration of cylinderical pipes of equal diameter.

III.) Construct the interpenetration of pipes with unequal diameter

INSTRUCTIONAL TECHNIQUES: Identification, explanation, questions and answers, demonstration, videos from source

INSTRUCTIONAL MATERIALS: Videos, loud speaker, textbook, pictures,

INSTRUCTIONAL PROCEDURES

PERIOD 1-2

NOTE

SURFACE DEVELOPMENT, INTERPENETRATION

Interpenetration refers to the occurrence where two or more solid objects overlap or intersect with each other. It's a crucial concept to understand because it helps designers and engineers ensure that components fit together properly without interference or conflict. It involves accurately representing the spatial relationship between different parts of a design to avoid clashes or errors during manufacturing or assembly.

The point at which a line intersects a plane or curved surface is called the piercing point.

Interpenetration of cylinderical pipes of equal diameter

To draw the curve of intersection for two cylinderical pipes of the same diameter joined at right angle and the development of pipe B.

Procedure

1. Draw the given elevations and plan of the pipes.
2. Draw a semi-circle each on the elevations and plan of pipe B and divide each of them into 6 equal parts and label each division.
3. Project horizontal lines from the points on the semi-circle of the plan to touch the plan of pipe A at 0¹, 1¹, 2¹ and 3¹.
4. Project vertical lines upward to points 0¹, 1¹, 2¹ and 3¹ to meet their corresponding horizontal lines from the semi-circle of the elevation, this marks the point of intersection.

To draw the development of pipe B

Procedure

1. Draw a straight line at a convenient distance equal in length to the length of the semi circle. That means transfering the distance of the semi circle on the line DV.
2. Project lines vertically upward from each division on line DV. Where these intersect with their corresponding lines from the curve of intersection, labelled I⁰, l¹, l², l³ marks the development of pipe B.

Interpenetration of pipes with unequal diameter

The construction of interpenetration of pipes with unequal diameter is laterally thesame to that of equal diameter the only difference is that since the pipes are of different diameters, their point of intersection is going to be a curve instead of a straight line.

For instance; Two pipes of unequal diameter intersect at an angle other than right angle, to draw to curve of intersection and the development of pipe B.

Procedure

1. To draw the curve of intersection, lines are projected vertically upward, from point l⁰, l¹, l² and l³ to intersect their corresponding lines projected from the points on the semi-circle of the elevation.

The points of the intersection of these lines, I.e, l⁰, l¹, l² and l³ marks the curve of intersection.

2. Project the lines at the right angle from each point on the curve of the intersection to the side of the pipe B.
3. At a convenient distance from pipe B of the elevation, transfer the distance from the semi-circle to the base line MN. Remember, the 12 divisions is the length of the circular shape of the pipe.
4. Project lines from Al the 12 divisions to intersect their corresponding lines from the points on the curve of intersection to obtain the development of pipe B.

EVALUATION: 1. Two unequal cylinders A and B intersect as shown in the third angle below. Draw the:

1. Curve of intersection of the cylinders
2. Surface development of cylinder B making XX the seam.

CLASSWORK: As in evaluation

CONCLUSION: The teacher commends the students positively