Lesson Notes By Weeks and Term v5 - Grade 12

Lesson Video

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Performance objectives

• Identify at least five types of industrial machines.
• Describe three different maintenance strategies.
• Evaluate the pros and cons of different maintenance strategies.
• Explain the importance of lubrication and alignment.
• Apply basic fault-finding techniques.

Lesson summary

Industrial machines are the backbone of South Africa's economy, driving sectors like mining, manufacturing, agriculture, and construction. Understanding how these machines function and how to maintain them effectively is crucial for ensuring their longevity, minimizing downtime, and maximizing productivity. This knowledge directly translates to job opportunities, economic growth, and sustainable industrial practices.

Furthermore, proper maintenance reduces the risk of accidents, creating safer working environments. A lack of maintenance leads to breakdowns, impacting production, costing businesses money, and potentially endangering workers.

Lesson notes

Types of Industrial Machines Lathes: Machine tools used for shaping metal or other materials by rotating the workpiece against a cutting tool. Common in manufacturing industries.

South African examples: Used to manufacture components for mining equipment.

Milling Machines: Machine tools used for shaping metal or other materials by removing material with a rotating cutter. Versatile and essential for precision engineering.

South African examples: Creation of automotive parts.

Conveyor Belts: Systems used to transport materials horizontally or vertically. Widely used in mining, manufacturing, and logistics.

South African examples: Movement of ore in mines, and packaging in factories.

Hydraulic Presses: Machines that use hydraulic fluid to exert force for shaping, forming, or cutting materials. Used in automotive, construction, and manufacturing.

South African examples: Shaping metal sheets for vehicle body panels.

CNC (Computer Numerical Control)

Machines: Automated machine tools that use computer programming to control their operations. Offer high precision and efficiency.

South African examples: Manufacturing of complex components for aerospace industries (nascent but growing).

Power Presses: Machines used to stamp or shape metal using dies. Used in the automotive and metal forming industries.

South African examples: Shaping metal sheets for appliances.

Welding Machines: Machines that join metal pieces together using heat and pressure. Used in construction, automotive and fabrication industries.

South African examples: Construction of pipelines. Maintenance Strategies Breakdown Maintenance (Run-to-Failure): This strategy involves repairing or replacing equipment only after it has broken down. It's the simplest and often the cheapest initially, but can lead to significant downtime and unexpected costs.

Advantages: Low initial cost, simple to implement.

Disadvantages: High downtime, unpredictable costs, potential for secondary damage, reduced safety. Preventative Maintenance (Time-Based Maintenance): This strategy involves performing maintenance at predetermined intervals, regardless of the equipment's condition. It aims to prevent breakdowns by regularly inspecting, lubricating, and replacing components.

Advantages: Reduced downtime, increased equipment lifespan, improved safety.

Disadvantages: Can be costly due to unnecessary maintenance, may not prevent all failures. Predictive Maintenance (Condition-Based Maintenance): This strategy uses sensors and monitoring systems to track the condition of equipment and predict when maintenance is needed. It allows for maintenance to be performed only when necessary, minimizing downtime and costs.

Advantages: Minimized downtime, reduced maintenance costs, improved equipment lifespan, optimized maintenance scheduling.

Disadvantages: High initial investment, requires specialized equipment and expertise.

Reliability-Centered Maintenance (RCM): A comprehensive maintenance strategy that focuses on identifying the critical functions of equipment and developing maintenance plans to ensure those functions are maintained. It considers the consequences of failure and uses a combination of preventative, predictive, and corrective maintenance techniques.

Lubrication Importance: Reduces friction between moving parts, preventing wear and tear, dissipating heat, and protecting against corrosion.

Types of Lubricants: Oils: Used for general lubrication. Viscosity is a critical factor.

Greases: Used for applications where oil would drip or leak. Good for high loads and slow speeds.

Solid Lubricants: Used in extreme conditions (e.g., high temperatures or vacuum).

Examples: graphite, molybdenum disulfide.

Selection Criteria: Load, speed, temperature, environment, material compatibility.

South African Context: In mining, specialized lubricants are needed to resist contamination from dust and water. In coastal factories, corrosion-resistant lubricants are essential.

Alignment Importance: Ensures that rotating parts are properly aligned, reducing stress on bearings, shafts, and couplings. Misalignment can lead to vibration, premature wear, and equipment failure.

Types of Misalignment: Parallel Misalignment: Shafts are offset but parallel.

Angular Misalignment: Shafts are at an angle to each other.

Combined Misalignment: A combination of parallel and angular misalignment.

Alignment Methods: Straightedge and Feeler Gauge: Simple method for rough alignment.

Dial Indicators: More accurate method for measuring misalignment.

Laser Alignment: The most accurate method for aligning shafts. Commonly used in industries with high precision equipment.

Fault Finding Systematic Approach: Identify the Problem: Gather information about the symptoms and the operating conditions.

Analyze the Problem: Determine the possible causes of the problem.

Test the Hypotheses: Perform tests to verify the causes.

Implement the Solution: Repair or replace the faulty components.