9.1 What is the main purpose of maintenance? 9.2 Briefly explain how basic preventative maintenance should be performed on the following systems: 9.2.1 Chain drive systems 9.2.2 Belt drive systems 9.3 State TWO properties of EACH of the following nylon products: 9.3.1 Polyethylene (PET) 9.3.2 Polypropylene (PP) 9.3.3 Polystyrene (PS) 9.4 State THREE factors that influence the coefficient of friction - NSC Mechanical Technology Fitting and Machining - Question 9 - 2022 - Paper 1

Basic preventative maintenance for chain drive systems includes:

• Cleaning uncovered drives to remove debris and contaminants.
• Checking the sprocket teeth and link plate for wear to prevent failures.
• Regularly applying lubricants to reduce friction and wear.
• Inspecting the functioning of tensioning devices to ensure proper chain tension.
• Checking chains regularly for elongation to maintain efficiency.

For belt drive systems, basic preventative maintenance includes:

• Checking the wear and tear on the belt to identify potential failures.
• Verifying belt alignment to prevent uneven wear.
• Checking the tension setting to ensure proper operation.
• Inspecting the tensioning devices to maintain appropriate tension.

1. Polyethylene (PET) is stiff and strong, making it suitable for various applications.
2. It exhibits good chemical resistance, ensuring durability in different environments.

1. Polypropylene (PP) has good fatigue resistance, allowing it to withstand repetitive stress.
2. It is tough and heat resistant, enabling use in high-temperature applications.

1. Polystyrene (PS) has good insulation properties, making it effective in thermal applications.
2. It is lightweight, facilitating easier handling and transportation.

1. Surface roughness or texture can greatly affect the interaction between two surfaces.
2. The temperature can alter the properties of materials and their engagement.
3. The type of lubricant used can change the frictional characteristics between surfaces.

Thermo-hardened composites undergo a chemical change during the moulding process, which makes them rigid and unable to remelt upon reheating. This property prevents them from being softened, shaped, or moulded again.

1. V-belt
2. Wedge belt / Cog belt
3. Flat belt