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The basic structure of a presentation has three main parts: Introduction, development and conclusion. You should know your audience, prepare the content, time management,... before the presentation. During the presentation, you should do eye contact, facial expression and confidence, on the contrary, you should not read directly from slides, overload with information and ignore time limits. You should thank the audience, answer questions, seek feedback and you should not rush off and dismiss negative feedback after the presentation. Finally, you want to impress the audience, you have to be confident, start strong and tailor to the audience.

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Last week I bought some ball bearings online to use in our group project. Ball bearings are probably the most common

type of bearings. These bearings are designed to handle both radial and thrust loads, and are usually found in applications

where the load is relatively small. Ball bearings work by transferring the load from the outer race to the ball and on to

the inner race. Since the ball is a sphere, it only contacts the inner and outer race at a very small point, which helps it spin

very smoothly, but it may become deformed and ruin the bearing if being overloaded. Because of these features and

functions, we used them in our skateboard that we made

ourselves.

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As I know, couplings have some functions that connecting shaft together to transmit power or disconnecting shaft for maintance. They are consisted of two parts that are input shaft to connect to the power sourse and the output shaft to connect to the destination. Couplings are divided into categories: rigid and flexible. Rigid couplings can be used to align the shaft with each other perfectly while flexile couplings can be used to transmit power without perfect alignment. The most common type of rigid and flexible coupling respectively is sleeve-style coupling and beam coupling. The function of sleeve-style coupling is to hold shaft in perfect alignment. Beside, it also can maximize performance and efficiency of the machine. Beam coupling serves to accommodate several degrees of shaft offset. It can be used when there's an offset. Moreover, beam coupling is to reduce vibration or noise. And that's all about the different kinds, the features of their components I want to share with you.

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Gears are machine component with teeth. Gear teeth mesh together to transmit torque. When two gears engage, they form a gearset. The driving gear is called a pinion. There are five common types of gears. They are spur gear, helical gear, bevel gear, worm gear and rack and pinion gear. Spur gear is the most common and simplest gear. It is cheap and easy to install, its teeth project towards or away from the center. Spur gear transmit motion and power between machine components. Helical gear is stronger, smoother than spur gear, its teeth are cut in a spiral shape. Helical gear helps reducing speed, noise and vibration. Bevel gears meet each other at an angle, usually 90 degrees. It transmit motion and power at an angle. Some gears have just one continuous tooth. These are called worms. A worm pairs with a worm gear. Worm gear mesh quieter and smoother. It transmits motion and power between machine components and reduces speed. Sometimes, gear convert rotational motion to linear motion. Rack and pinion gears serve this purpose.

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Two types of drives are belt drives and chain drives. Both can be used to move objects by attaching pockets, buckets, or frames to them; chains are often used to move things vertically by holding them in frames, while belts are good at moving things horizontally. Chain drives are most often made of metal, while belts are often rubber, plastic, urethane, or other substances. Belt drives can slip unless they have teeth, which means that the ouput side may not rotate at a precise speed, and some work gets lost to the friction of the belt as it bends around the pulleys. Chains wear out faster than belts if not properly lubricated. Belts have low heat resistance while chain drives have high heat resistance. Belt drives reduce noise and vibration while chains cause noise and vibrations. We can see the the application of chain drives in industrial toasters, while belts are in the form of conveyor belts. It is not unusual for the systems to be used in combination; for example the rollers that drive conveyor belts are themselves often driven by drive chains.

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AutoCAD is a commercial computer-aided design (CAD) and

drafting software application that is used for precise 2D and 3D

drafting, design, and modeling with solids, surfaces, mesh

objects, and more. With AutoCAD, you will have access to

many useful features that can help automating tasks and

increasing productivity such as comparing drawings, counting,

adding objects, and creating tables. It also comes with seven

industry-specific toolsets for electrical design, plant design,

architecture layout drawings, mechanical design, 3D mapping,

adding scanned images, and converting raster images. The

software has some advantages. Firstly, it accelerate your design

with its automations and customizations. Secondly, you can

share drawings safely and securely and collaborate across

desktop, web or mobile devices. Last, only this software has

technology to ensure fidelity and compatility for our DWGs,

which are files for storing 2- and 3-D design data.

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Computer-Aided Design (CAD) refers to use of computer software to create precise drawings and models, while manual drafting involves traditional techniques using pencils, rulers, and drafting boards. CAD offers several advantages, including enhanced accuracy, ease of modifications, and the ability to create complex designs quickly. It also facilitates collaboration through digital sharing and storage. However, it requires a learning curve and access to technology, which can be a drawback for some. In contrast, manual drafting promotes a deep understanding of design principles and is less dependent on technology, allowing for a more hands-on approach. However, it can be time-consuming and less precise, with limited capabilities for modifications. Ultimately, while CAD streamlines the design process and enhances productivity, manual drafting fosters creativity and a tactile connection to the work.

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The diagram shows how to make a car wheel.

Overall, there are five distinct stages in the process, beginning with casting aluminum material and ending with inspector checks of the product.

In the first stage,making alloy cast wheels, aluminum is heated until it becomes molten. Then, with the help of a vacuum-type tool, the aluminum is cast into its final shape after being poured into a mold.The cast is perfectly drilled and trimmed once it cools. Although the casting process is quick and affordable, it has the drawback of producing a less durable material than a forged wheel.

Next stage, the car wheel is grinded and polished by engineers, in order to make it smooth.

Finally, the inspector checks the product before selling it.

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Plastic is a versatile synthetic material made from polymers, characterized by properties such as lightweight, durability, and resistance to corrosion. These attributes enable a wide range of applications, from packaging and automotive components to medical devices. The advantages of plastic include its cost-effectiveness, ease of molding into complex shapes, and insulation properties. However, its disadvantages are significant; plastics often contribute to environmental pollution, as they are not biodegradable and can persist in ecosystems for centuries. The future of plastic likely involves a dual approach: advancements in biodegradable plastics and recycling technologies to mitigate environmental impacts while still capitalizing on their beneficial properties. As society increasingly prioritizes sustainability, innovations in eco-friendly materials and circular economy practices will be crucial in reshaping the role of plastic in our lives.

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Plastics can be broadly categorized into two main types: thermoplastics and thermosetting plastics. Thermoplastics, such as Polyethylene (PE), Polypropylene (PP), and Polyvinyl Chloride (PVC), are known for their flexibility, ease of molding, and recyclability, making them ideal for packaging, containers, and pipes. Thermosetting plastics, like Epoxy and Phenolic are rigid and heat-resistant once cured, suitable for electrical insulators and high-stress applications. Other notable types include Polystyrene (PS), valued for its insulation properties in packaging and disposable cutlery, and Acrylonitrile Butadiene Styrene (ABS), known for its toughness and used in automotive parts and consumer goods. Each plastic type has unique properties that dictate its suitability for various mechanical and industrial applications.

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The process depicted is casting, a manufacturing technique used to shape metal into a desired form by pouring molten metal into a mold. There are four main steps in the casting process. First, pattern making involves creating a replica of the part to be cast, usually from wax, wood, or metal. The second step, mold making, involves forming a mold around the pattern, typically using sand or metal. In the third step, melting, the metal is heated to a liquid state in a furnace. Finally, the molten metal is poured into the mold cavity, where it cools and solidifies, taking the shape of the pattern. Once solidified, the mold is removed, and the casting is finished, often requiring cleaning and finishing steps to remove excess material and achieve the desired surface quality.

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Plastic injection molding is a widely used manufacturing process, but several common issues can affect part quality. One typical problem is warping, which occurs when the cooled part shrinks unevenly due to temperature or cooling rate discrepancies. This can be caused by uneven mold temperature or incorrect cooling time. A solution is to optimize mold temperature and cooling rates to ensure uniform contraction. Another issue is short shots, where the mold is not completely filled with material, leading to incomplete parts. This can be caused by insufficient injection pressure or inadequate material flow. To resolve this, adjusting injection speed, pressure, or modifying the gate design can help ensure full mold filling. Surface defects, such as sinks or burns, may occur due to high injection pressures or improper mold venting. Reducing injection pressure and ensuring proper venting can mitigate these problems. Lastly, flash occurs when excess material escapes the mold cavity. This is typically caused by excessive injection pressure or poor mold alignment, which can be corrected by adjusting mold closure force and maintaining precise mold alignment.

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The machine tool in question is a milling machine, which requires regular maintenance to ensure optimal performance and longevity. There are five key maintenance tasks outlined. Daily tasks include cleaning the guideways to avoid interruptions and ensure smooth fluid motion, and inspecting the oil level to maintain engine efficiency and prevent overheating. Every semi-annually, it is necessary to renew the oil to ensure smooth operation. Weekly, the machine should be cleaned thoroughly to remove dust and dirt, preventing buildup that could affect performance. Finally, an annual inspection of bearing slackness is required to prevent slippage and maintain precise machining. Adhering to these maintenance schedules helps keep the milling machine running efficiently and extends its lifespan