Lesson Notes By Weeks and Term v5 - Grade 12

Lesson Video

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Performance objectives

• Identify outstanding PAT requirements using marking guidelines.
• Organize your portfolio to show the design process.
• Critically evaluate your own work for improvement.
• Apply correct drawing standards and conventions.
• Manage your time to meet submission deadlines.

Lesson summary

This week is crucial in ensuring the successful completion of your Engineering Graphics and Design (EGD) Portfolio and Practical Assessment Task (PAT). The PAT constitutes a significant portion of your final Grade 12 mark. Excelling in your PAT demonstrates your proficiency in applying theoretical knowledge to practical problem-solving, a skill highly valued in engineering and design fields. In South Africa, with its growing infrastructure development and manufacturing sectors, skilled EGD practitioners are in high demand. Completing the PAT successfully not only contributes to your academic success but also equips you with essential skills for future career opportunities.

Lesson notes

Understanding the PAT and Portfolio: The Practical Assessment Task (PAT) is a substantial project completed throughout the year. It is not just a drawing exercise; it's a design project that involves problem identification, research, conceptualization, development, and refinement. The PAT requires you to apply your EGD knowledge and skills to solve a realistic problem. In Grade 12, PAT topics often relate to civil, mechanical, or electrical engineering applications. This week, you should be focusing on refining the final drawings, ensuring accurate dimensions, correct use of line types, appropriate layers (if using CAD), and adherence to relevant SANS standards. The Portfolio is a collection of your work throughout the year, showcasing your progress and skills development. It's more than just a collection of drawings. It documents your learning journey, including initial sketches, design iterations, research notes, and reflections on your work. The portfolio should demonstrate your understanding of design principles, problem-solving skills, and ability to communicate technical information effectively.

Key Areas to Focus On This Week: Accuracy: Double-check all dimensions, angles, and specifications in your drawings. Errors, even small ones, can significantly impact your grade. Use a reliable measuring tool (ruler, compass, protractor) and cross-reference dimensions with your design calculations. For CAD drawings, verify dimensions using the software's measuring tools.

Drawing Standards: Ensure you are adhering to the latest SANS standards (e.g., SANS 10111 for technical drawings). This includes line types, lettering, dimensioning, and symbols. Pay close attention to detail – are your hidden detail lines dashed correctly? Is your dimensioning aligned and clear? Are your section lines angled appropriately?

Clarity and Presentation: Your drawings and portfolio must be easy to understand. Use clear and concise lettering, well-organized layouts, and appropriate annotation. Use different line weights to differentiate between object lines, hidden lines, and dimension lines. For CAD drawings, use layers effectively to organize your drawing elements. A well-presented portfolio reflects professionalism and attention to detail.

Design Justification: The portfolio should clearly explain the reasoning behind your design decisions. Why did you choose a particular material? Why did you use a specific dimension? Why did you opt for one design solution over another? Provide evidence to support your choices, such as research data, calculations, or comparisons of different options.

Functionality and Feasibility: Your PAT design must be functional and feasible. Consider factors such as material availability, manufacturing processes, cost, and environmental impact. Ensure that your design can be realistically implemented in a real-world setting.

CAD Considerations (if applicable): Ensure your CAD files are organized with layers, blocks, and proper drawing scales. Check for accuracy and consistency in your CAD drawings. Provide clear print layouts with title blocks and appropriate views.

Worked example

Example 1: Dimensioning Error Correction

Problem: A Grade 12 student incorrectly dimensioned a rectangular block in their PAT drawing. The actual length was 150mm, but the drawing showed 140mm.

Solution: The student must correct the dimension to 150mm. Additionally, in the portfolio, they should document this error and explain how they identified and corrected it. This demonstrates attention to detail and a commitment to accuracy. They might include a screenshot (if using CAD) showing the original incorrect dimension and the corrected dimension.

Why: Accuracy is paramount in engineering drawings. A 10mm error could have significant consequences in real-world construction or manufacturing.

How: Use a ruler or CAD software to verify the dimensions. Ensure the dimension lines extend correctly from the extension lines and that the dimension text is clear and legible.

Example 2: Addressing Feedback on Sectional Views

Problem: A teacher provides feedback that the section lines in a sectional view are not correctly oriented at 45 degrees and are too close together.

Solution: The student needs to redraw the section lines at a precise 45-degree angle using a set square or CAD tools. The spacing between the lines should be uniform and appropriate for the size of the drawing (typically 2-3mm). In the portfolio, the student should explain the purpose of sectional views and the importance of correct section lining to clearly indicate the cut surface.

Why: Sectional views are used to reveal internal features of an object. Correct section lining helps to distinguish the cut surface from other parts of the object.

How: Use a set square or protractor to ensure accurate 45-degree angles. Maintain consistent spacing between the section lines.

Example 3: Design Justification for Material Selection

Problem: In a design for a bus shelter, the student chose to use steel for the frame.

Solution: The student needs to provide a justification for this material choice in their portfolio.

This could include factors such as:

Strength and Durability: Steel is strong and durable, able to withstand the weight of the roof and potential wind loads.

Availability and Cost: Steel is readily available in South Africa and relatively cost-effective compared to other materials like aluminum.

Weldability: Steel is easily weldable, making it suitable for constructing the frame.

Corrosion Resistance (with treatment): The student should mention that the steel will need to be treated with a coating (e.g., galvanizing or painting) to prevent corrosion.

Sustainability (optional): The student could also mention that steel is recyclable.

Guided Practice (With Solutions)

Question 1: