Lesson Notes By Weeks and Term v5 - Grade 10

Lesson Video

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Performance objectives

• Identify different types of lubricants and their applications.
• Demonstrate correct lubrication procedures.
• Describe and apply safe cleaning methods for machines.
• Identify common signs of machine malfunction.
• Understand and create a simple maintenance checklist.

Lesson summary

This week, we delve deeper into basic machine operations and maintenance, specifically focusing on lubrication, cleaning, and basic fault finding. Understanding these principles is crucial not just for your Mechanical Technology course, but also for daily life. In South Africa, where manufacturing and maintenance are vital sectors, skills in machine maintenance are highly valued and can lead to various career paths, from artisan trades to engineering. Proper maintenance extends the lifespan of machinery, saves money on repairs, and ensures safe operation, contributing to both personal and national economic well-being.

Lesson notes

2.1 Lubrication Lubrication is the process of reducing friction between moving surfaces by introducing a lubricant between them. This minimizes wear and tear, reduces heat generation, and improves efficiency. Different machines require different types of lubricants depending on factors such as operating temperature, speed, load, and environmental conditions.

Types of Lubricants: Oils: Generally used for high-speed, low-load applications. Oils can be mineral-based, synthetic, or vegetable-based. Mineral oils are most common and are derived from petroleum. Synthetic oils offer superior performance in extreme temperatures. Vegetable oils are biodegradable and environmentally friendly, but may not perform as well under high temperatures.

Greases: Used for slow-speed, high-load applications. Grease consists of oil mixed with a thickener (usually soap) and additives. The thickener holds the oil in place, providing a continuous supply of lubricant to the moving parts.

Solid Lubricants: Used in extreme conditions where oils and greases cannot be used (e.g., high temperatures, vacuum). Examples include graphite, molybdenum disulfide (MoS2), and Teflon (PTFE).

Selecting the Right Lubricant: Refer to the machine's manufacturer's manual for the recommended lubricant.

Consider the following: Viscosity: A measure of a fluid's resistance to flow. High viscosity oils are thicker and suitable for high loads and slow speeds. Low viscosity oils are thinner and suitable for high speeds and low loads.

Operating Temperature: The lubricant must maintain its properties at the operating temperature of the machine.

Load: The lubricant must be able to withstand the load applied to the moving parts.

Environmental Conditions: Consider factors such as dust, moisture, and corrosive substances.

Application Methods: Manual Lubrication: Using an oil can or grease gun to apply lubricant directly to the moving parts.

Drip Feed Lubrication: Oil is dripped onto the moving parts at a controlled rate.

Splash Lubrication: The moving parts dip into an oil bath, splashing oil onto other parts.

Pressure Lubrication: Oil is pumped through a system of pipes and nozzles to lubricate the moving parts.