Lesson Notes By Weeks and Term v3 - Senior Secondary 2
fabrication of non-metals
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fabrication of non-metals
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Subject: Welding & Fabrication
Class: Senior Secondary 2
Term: 1st Term
Week: 1
Theme: Practical Works / Projects
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Students should be able to fabricate a non- ferrous metal in to a required shape or object
Practical Works / Projects fabrication of non-metals (Focus: Non-ferrous Metals)
Term: 1st Term Week: 32 ---
1. Overview and Learning Objectives This lesson focuses on the practical aspects of fabricating non-ferrous metals, which are essential materials in various industries due to their unique properties. Understanding and applying fabrication techniques for non-ferrous metals equips students with valuable skills for careers in construction, manufacturing, plumbing, electrical works, and artistry within Nigeria. The ability to manipulate these materials into desired shapes is a fundamental skill for any aspiring welder or fabricator.
Specific Performance Objectives: Upon completion of this lesson, students will be able to: Identify various non-ferrous metals and their common applications in Nigeria. Explain the properties of non-ferrous metals relevant to fabrication processes. Select appropriate tools and equipment for marking, cutting, bending, and joining non-ferrous sheet metals. Fabricate a simple object, such as a cylinder, from a sheet of non-ferrous metal according to specified dimensions. Apply safety precautions during the fabrication of non-ferrous metals.
Real-World Applications in Nigeria: The skills acquired in fabricating non-ferrous metals are highly applicable in various Nigerian sectors: Construction: Forming aluminum window frames, galvanized iron roofing sheets (though GI is steel, fabrication principles apply), copper piping for water systems.
Manufacturing: Production of cooking utensils (aluminum pots and pans), electrical components (copper wires, brass terminals), vehicle parts.
Art and Craft: Creation of decorative items, sculptures, and jewelry from brass, copper, or aluminum.
Repair and Maintenance: Repairing and fabricating replacement parts for machinery, plumbing systems, and domestic appliances.
Entrepreneurship: Students can leverage these skills to start small-scale fabrication businesses, producing items like water tanks, dustbins, or custom metalwork for local communities.
2. Key Concepts and Explanations Clarification on Topic Title: While the topic is broadly stated as "fabrication of non-metals," in the context of Welding & Fabrication and given the specific performance objectives and evaluation guide, this lesson will focus specifically on non-ferrous metals. This distinction is crucial as "non-metals" can also refer to materials like plastics, wood, or composites, which fall outside the typical scope of metal fabrication in this curriculum context.
A. Definition of Non-Ferrous Metals: Non-ferrous metals are metals that do not contain iron in significant amounts. They are generally more expensive than ferrous metals but possess desirable properties such as low weight, higher conductivity (electrical and thermal), non-magnetic properties, and superior corrosion resistance.
B. Common Non-Ferrous Metals and their Applications in Nigeria:
1. Aluminum (Al): Properties: Lightweight, excellent corrosion resistance (due to passive oxide layer), good electrical and thermal conductivity, non-magnetic, highly ductile and malleable.
Applications: Roofing sheets, window frames, cooking utensils (pots, pans), beverage cans, electrical transmission lines, aircraft components, vehicle bodies.
2. Copper (Cu): Properties: Excellent electrical and thermal conductivity, highly ductile and malleable, corrosion resistant (forms a green patina over time), attractive reddish-brown color.
Applications: Electrical wiring, plumbing pipes and fittings, roofing, heat exchangers, decorative items, craftwork.
3. Brass (Cu-Zn Alloy): Properties: Good corrosion resistance, pleasing appearance, easily machined, good electrical conductivity, stronger than pure copper, lower melting point than copper.
Applications: Plumbing fittings (taps, valves), musical instruments, decorative items, hardware (hinges, locks), electrical connectors.
4. Bronze (Cu-Sn Alloy): Properties: Stronger and harder than brass, good corrosion resistance, good bearing properties.
Applications: Bearings, gears, sculptures, marine fittings.
5. Zinc (Zn): Properties: Relatively soft, low melting point, excellent corrosion resistance (often used as a protective coating).
Applications: Galvanizing steel (coating steel to prevent rust), battery casings, die-casting alloys.
6. Lead (Pb): Properties: Very dense, soft, highly malleable, excellent corrosion resistance, high toxicity (limited use).
Applications: Batteries, radiation shielding, roofing flashings, weights (though less common due to toxicity).
C. Fabrication Processes for Non-Ferrous Metals (Focus on Sheet Metal Work): Fabrication involves the process of cutting, shaping, and joining materials to create a desired product. For non-ferrous sheet metals, the typical processes include:
1. Measuring and Marking Out: Purpose: To accurately transfer dimensions from a drawing onto the sheet metal.
Tools: Steel rule, tape measure, scriber, surface gauge, divider, centre punch, hammer (for punching).
Procedure: Clean the surface of the metal. * Use a steel rule allow students to verbally explain processes back to the teacher or peers.
Kinesthetic Learners: Emphasize hands-on practical work, allow repeated practice with tools, and provide simplified small-scale models to work on first.
B. Remediation (For Struggling Learners):
1. Simplified Tasks: Break down the cylinder fabrication into smaller, manageable steps (e.g., first focus only on accurate marking and cutting, then on forming a simple curve, then on joining). Provide pre-marked or pre-cut sheets for initial practice in bending and joining. Use softer, thinner gauge metals that are easier to work with.
2. Increased Teacher Support: Provide one-on-one guidance during practical sessions, demonstrating steps slowly and allowing the student to mimic immediately. Pair struggling learners with more proficient peers for peer tutoring and support.
3. Repetitive Practice: Allocate extra time for practicing fundamental skills like measuring, marking, and using hand snips. Provide simpler shapes (e.g., a straight bend) before attempting a cylinder.
4. Resource Provision: Offer simplified visual aids or checklists for each step of the fabrication process.
C. Extension/Enrichment (For High-Achieving Learners):
1. Advanced Fabrication Projects: Challenge students to fabricate more complex shapes (e.g., a conical shape, a rectangular box with a lid, or a small funnel). Encourage them to explore different joining methods beyond riveting, such as soldering or brazing, and understand their specific applications and requirements.
2. Design and Planning: Task students with designing a practical non-ferrous metal item for a specific local need (e.g., a small watering can for gardening, a custom bracket for a solar panel) and then fabricating it. This involves dimensioning, material selection, and considering functional requirements.
3. Material Exploration: Research and compare the properties and fabrication challenges of different non-ferrous alloys (e.g., different grades of aluminum or brass), and how these affect their practical applications. Explore how to calculate material wastage and optimize material usage for cost-effectiveness in a local workshop setting. tools (snips), forming tools (mallet, pipe/stake, or bending rolls), and joining tools (pop rivet gun, rivets, drill, or soldering kit).
Assessment Criteria / Rubric: | Criteria | Excellent (4 marks) | Good (3 marks) | Satisfactory (2 marks) | Needs Improvement (1 mark) | Score | | :----------------------- | :------------------------------------------------------------------------------- | :------------------------------------------------------------------------------- | :---------------------------------------------------------------------------- | :-------------------------------------------------------------------------------- | :---- | |
1. Measuring & Marking | Highly accurate dimensions; clear, precise, and correct marking. | Mostly accurate dimensions; clear and correct marking. | Some inaccuracies in dimensions or marking, but generally understandable. | Significant errors in dimensions or marking; unclear. | | |
2. Cutting | Clean, straight cuts along marked lines; deburred edges. | Mostly clean cuts, slight deviations; edges mostly deburred. | Jagged cuts, significant deviations from lines; edges not fully deburred. | Poor, unsafe cuts; edges not deburred. | | |
3. Forming/Bending | Smooth, uniform cylindrical shape; minimal distortion; correct curvature. | Mostly uniform curve; minor distortions; acceptable curvature. | Uneven curvature; noticeable distortions or kinks. | Poorly formed; significantly off-shape; major kinks. | | |
4. Joining (Seam) | Strong, neat, and secure joint (e.g., well-set rivets, clean solder joint). | Joint secure and functional; minor cosmetic imperfections. | Joint is functional but weak or visually untidy. | Joint is loose, insecure, or fails. | | |
5. Adherence to Safety | Consistently observed all safety rules; proper use of PPE and tools. | Generally observed safety rules; minor lapses. | Occasional disregard for safety rules; inconsistent PPE use. | Frequent disregard for safety rules; unsafe tool handling. | | | Total Score | | | | | /20 | Written Assessment: Questions from the "Independent Practice" section can be used as a written test to assess theoretical knowledge, problem-solving, and understanding of concepts.
For example: "Describe the detailed procedure for fabricating a cylindrical object from a flat sheet of aluminum, from marking out to the final joining process." (This assesses their understanding of the complete practical process.)
7. Real-life Applications / Integration
1. Local Entrepreneurship and SME Development: Students can apply fabrication skills to start small businesses (SMEs) producing household items like water storage tanks (from aluminum or galvanized sheets), dustbins, buckets, or custom-made metal enclosures for local electronics (e.g., for inverters, solar charge controllers). This aligns with government efforts to promote skill acquisition and self-employment among Nigerian youths. They can also get contracts for fabricating specialized parts for local industries like palm oil processing plants or cassava mills.
2. Infrastructure Development and Maintenance: Knowledge of non-ferrous metal fabrication is crucial for maintaining and expanding Nigeria's infrastructure. This includes fabricating and repairing copper pipes in plumbing systems for homes and commercial buildings, shaping aluminum sheets for roofing and ceiling applications, and making brass fittings for water distribution systems. Graduates can work as skilled plumbers, roofers, or general fabricators in construction companies across the country.
3. Art, Craft, and Cultural Preservation: Non-ferrous metals like copper, brass, and bronze are integral to Nigerian traditional arts and crafts, such as lost-wax casting and metal sculpture (e.g., Benin bronzes). Fabrication techniques can be adapted for modern artistic expression and craft production, creating decorative items, jewelry, and souvenirs that reflect Nigerian culture. This also provides an avenue for income generation through sales to tourists and local markets, contributing to cultural tourism.
8. Differentiation, Remediation and Extension
A. Differentiation (Supporting Diverse Learners): Visual Learners: Provide detailed diagrams, step-by-step illustrated guides for cylinder fabrication, and video demonstrations where possible. Use colour-coding for different parts of a drawing.
Auditory Learners: Explain concepts clearly, encourage questions, and allow students to verbally explain processes back to the teacher or peers.
Kinesthetic Learners: Emphasize hands-on practical work, allow repeated practice with tools, and provide simplified small-scale models to work on first.
B. Remediation (For Struggling Learners):
1. Simplified Tasks: Break down the cylinder fabrication into smaller, manageable steps (e.g., first focus only on accurate marking and cutting, then on forming a simple curve, then on joining). Provide pre-marked or pre-cut sheets for initial practice in bending and joining. * Use softer, thinner gauge metals that are easier to