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To make an effective presentation, you should follow a clear structure: greeting, introduction, body, and conclusion. Before presenting, prepare your content carefully, organize it logically, and rehearse to build confidence. During the presentation, speak clearly, maintain eye contact, and use visual aids to support your ideas. Avoid reading slides word-for-word or speaking too fast. After the presentation, invite questions and respond politely, even if you don’t know the answer. Never ignore the audience’s feedback. To impress listeners, show enthusiasm, use relevant examples, and connect your message to their interests or needs. A confident attitude and a well-prepared talk will leave a strong impression. Remember, your goal is not only to inform but also to engage and inspire your audience. With practice and attention to detail, anyone can deliver a successful presentation.

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To: Supervisor From: Apprentice Engineer Date: September 15, 2025

I’ve purchased three types of bearings: ball bearings, tapered roller bearings, and thrust roller bearings from Minh Phat Mechanical Supplies two days ago.

Ball bearings include inner and outer races with balls, used for supporting radial and axial loads in fans and washing machines. Tapered roller bearings handle heavy radial and thrust loads, ideal for car hubs. Thrust roller bearings support large thrust loads, commonly used in gear sets.

All items meet our requirements and are ready for use

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I purchased three types of bearings—ball bearings, roller bearings, and thrust bearings—from Hanoi Mechanical Supplies on September 15th. Ball bearings consist of steel balls between two races and are ideal for reducing friction in rotating shafts. Roller bearings use cylindrical rollers and are suited for heavy radial loads in conveyor systems. Thrust bearings, made of flat races and balls, handle axial loads and are used in automotive transmissions. Each bearing includes an inner ring, outer ring, rolling elements, and a cage to maintain spacing. Seals are added to prevent contamination. These bearings will be used across our machinery to improve efficiency, reduce wear, and ensure smooth operation. I ensured all items meet ISO standards and are ready for installation

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A gear is a mechanical component with teeth that mesh with another gear to transmit torque and rotational motion. Gears are used to change the speed, direction, and torque of a mechanical system. There are several common types of gears, including spur gears, bevel gears, worm gears, and helical gears. Spur gears have straight teeth and are used for transmitting motion between parallel shafts. Bevel gears have conical shapes and are designed for shafts that intersect, often at a 90-degree angle. Worm gears consist of a screw-like worm and a worm wheel, offering high torque and compact design, commonly found in elevators or conveyor systems. Helical gears have angled teeth and provide smoother and quieter operation, suitable for high-speed applications. Each type of gear has unique features and is chosen based on specific mechanical requirements in industries like automotive, manufacturing, and robotics.

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There are two common types of mechanical drives: belt drive and chain drive. Both are used to transmit power between shafts, but they differ in structure and performance. A belt drive uses a flexible belt made from rubber or synthetic materials and is known for smooth and quiet operation. However, it may experience slippage, reducing efficiency. In contrast, a chain drive uses metal chains and sprockets, which prevent slippage and provide higher transmission efficiency. Chain drives are more durable and suitable for heavy loads, but they require more maintenance due to wear and the need for lubrication. Belt drives are often found in fans, washing machines, and conveyors, while chain drives are widely used in motorcycles, bicycles, and industrial machinery. Depending on the application, each type offers specific advantages in cost, durability, and performance.

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CAD (Computer-Aided Design) is the use of computer software to create precise drawings and technical illustrations, while manual drafting involves creating drawings by hand using tools like pencils, rulers, and drafting boards. CAD offers many advantages over manual drafting, such as greater speed, accuracy, and the ability to easily edit or duplicate designs. It also allows for 3D modeling and digital storage, which saves time and physical space. In contrast, manual drafting requires more time and effort, and making changes often means redrawing large sections. However, manual drafting can help develop a stronger understanding of drawing techniques and spatial awareness. While CAD is ideal for complex and large-scale projects, manual drafting may still be useful in basic design work or educational settings. Overall, CAD is the more efficient and versatile option for most modern design tasks.

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One widely used CAD program is AutoCAD, developed by Autodesk. AutoCAD is known for its powerful 2D and 3D design capabilities, making it popular in fields like architecture, engineering, and interior design. Key features include precise drawing tools, layer management, 3D modeling, annotation tools, and compatibility with various file formats. Users can create detailed floor plans, technical schematics, and 3D visualizations. One major advantage of AutoCAD is its accuracy and efficiency, especially when making modifications or sharing files digitally. It also supports automation through custom scripts and plugins. However, AutoCAD has some disadvantages, such as its high cost and steep learning curve for beginners. Despite this, AutoCAD remains a leading choice in the industry due to its versatility, reliability, and extensive support for professional design tasks.

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Aluminum Alloy Wheel Manufacturing Process

This manufacturing process is called Casting and is used to produce aluminum alloy wheels. The entire procedure takes place over four main steps. The first step is Casting, when molten aluminum is poured into a mold to create the basic shape of the wheel. After that, it moves to the second step, Turning/Cutting, before the wheel is completely cooled, a CNC machine removes excess material and creates precise details on the wheel's surface. The third step is Drilling; after the wheel has achieved its basic shape, the bolt holes and other necessary features are accurately drilled. Finally, the fourth step is Surface Finishing, after which a protective paint layer or other finish is applied to enhance aesthetics and durability. Finally, the finished product undergoes quality inspection before being introduced to the market.

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Nx a powerful, integrated CAD/CAM/CAE software developed by Siemens Digital Industries Software. It is widely used in industries such as aerospace, automotive, and advanced manufacturing for designing complex products, simulating performance, and programming CNC machines. NX offers advanced features for 3D modeling, parametric design, simulation, and product lifecycle management (PLM), making it a comprehensive solution for end-to-end product development. Its flexibility and high-performance capabilities make it a preferred choice for engineers and designers working on complex engineering tasks.

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Plastic is a synthetic material made from polymers derived mainly from petroleum. It has a wide range of properties, such as low density, corrosion resistance, electrical insulation, flexibility, and ease of molding into different shapes. These characteristics make plastics useful in various applications, including packaging, automotive parts, and household products. The advantages of plastic include its light weight, durability, and cost-effectiveness. However, its major disadvantages are poor biodegradability, contribution to pollution, and harmful effects on marine life and ecosystems. In the future, the development of biodegradable and recyclable plastics is expected to increase, reducing environmental damage. Advances in materials engineering may also produce stronger, more sustainable plastic alternatives made from renewable resources, balancing performance and eco-friendliness.

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There are seven main types of plastics, each with unique properties and applications. Polyethylene terephthalate (PET, code 1) is lightweight, strong, and commonly used for beverage bottles. High-density polyethylene (HDPE, code 2) is durable and resistant to chemicals, ideal for containers and pipes. Polyvinyl chloride (PVC, code 3) is tough and versatile, used in plumbing and window frames. Low-density polyethylene (LDPE, code 4) is flexible and used for plastic bags and film wraps. Polypropylene (PP, code 5) has high melting resistance, suitable for automotive parts and food containers. Polystyrene (PS, code 6) is rigid or foam-like, used in packaging and disposable cutlery. Other plastics (code 7) include polycarbonate and bioplastics, used in electronics and sustainable materials. Understanding these types helps engineers choose the right plastic for performance, safety, and environmental sustainability.

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The process shown in the figure is called injection moulding of plastic. It is one of the most common methods used to produce plastic parts with complex shapes. The process has three main steps: feeding, melting and injection, and cooling. First, plastic pellets are fed into the hopper, where they fall into a heated cylinder containing a rotating screw. The heat and the movement of the screw melt the plastic into a thick liquid. Next, the molten plastic is injected through the nozzle into a mould cavity using high pressure. Finally, the plastic cools and solidifies in the shape of the mould. Once cooled, the mould opens, and the finished plastic part is ejected. Injection moulding is widely used because it is fast, precise, and suitable for mass production

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Plastic injection moulding can face several common problems that affect product quality. One typical issue is warping, which occurs when parts cool unevenly, causing deformation. This can be solved by improving cooling time and ensuring uniform wall thickness. Another problem is short shots, where the mould cavity is not completely filled. This usually happens due to low injection pressure or poor venting, and can be fixed by increasing pressure or cleaning vents. Flash, or excess plastic around part edges, occurs when moulds are not clamped tightly; tightening the clamping force or repairing the mould helps prevent it. Burn marks may appear due to trapped air or excessive heating, which can be reduced by adjusting temperature and improving venting. Regular machine maintenance and proper process control help minimize these problems and ensure consistent product quality

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The machine tool that needs maintenance is a milling machine. There are five types of maintenance work required to keep it in good condition. These are cleaning the guideways, inspecting the oil level, renewing the oil, cleaning the machine thoroughly, and inspecting bearing slackness. The guideways and oil level should be checked and cleaned daily to avoid interruptions, control fluid motion, and prevent overheating. The machine should be cleaned thoroughly every week to remove dust and dirt. The oil needs to be renewed every six months to ensure smooth operation, and the bearings should be inspected once a year to prevent slippage. By following this maintenance schedule, customers can ensure the milling machine runs efficiently and has a longer service life.