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The structure of a presentation should be an introduction, body, and conclusion. The introduction is the part where we greet the audience and state the purpose of the presentation. The body is the part that covers most of the content. The ending is the greetings. Before the presentation, you need to follow some tips. Firstly, you should know your audience. Seconly you need to choose a presentation style. Next you should practice and internalize. You should not use your phone. During the presentation you should use gestures and body language to express ideas. You should not just look at the paper and read. After the presentation You should thank the audience after the ask you a question. That is all I want to share. Thanks for looking

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Couplings are common mechanical devices. They are used to connect shafts together to transmit power and disconnect shafts for maintenance easily. There are two main: flexible coupling and rigid coupling. The most common type of flexible coupling is beam coupling. Flexible coupling can reduce noise and unwanted vibration. Besides it allows for misalignment. Moreover, it can accommodate several degrees of shaft offset. Unlike flexible coupling, rigid coupling is used to align shafts with each other. It also helps maximize performance and efficiency. Furthermore, it reduce wear on the machine. The most common type of rigid coupling is sleeve style coupling.

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There are two types of beaning: rolling contact bearings and journal bearing. Journal bearing has no rolling parts. The shaft rotates inside lubricated sleeve. It allows high load-carrying capacity. Unlike journal bearing, rolling contact bearings have rolling parts. They have inner race and outer race. They use rollers to support loads. It has low-medium load-carrying capacity. Rolling contact bearings have four types including: ball bearings, straight roller bearings, tapered roller bearings and thrust roller bearings. Firstly, ball bearings are used to support radial and axial load using spherical rollers. Secondly, straight roller bearings are used for supporting radial motion using cylindrical roller. Thirdly, , tapered roller bearings used to support radial forces and moderate thrust forces. Finally, thrust roller bearings used for supporting thrust forces using barrel-shaped roller.

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Gear is a rotating circular component of machine with teeth which mesh with another toothed part. The main function of gears are transmit torque and change the speed torque and direction of the power source. There are 5 different kinds of gears which are spur gear, helical gears, worm and worm gear, rack and pinion gear, bevel gear. Firstly Spur gear have teeth projecting towards or away from the centre. It is used to reduce speed applications. Secondly, Helical gears have their teeth cut in a spiral shape which for running more smoothly and quietly and controlling noise. Thirdly worm and worm gear is pairs with a worm gear, it have just one continuous tooth. Which reduces to speed. Next rack and pinion is consist of the circular gear engaging a linear gear .its function is to convert rotational motion into linear motion. Finally bevel gear is a conical form. It is used to transmit rotational power through shafts at an angle, normally 90 degrees.

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two types drives are belt drive and chain drive. Belt drive is used to transmit powers from one shaft to another by means of pulleys. Chain drive is to transmit between parallel shafts. Belt drive is made from rubber, plastic, and chain driver is made from metal. Unlike belt drive, chain driver cause noise and vibrations. Belt drive are different to chain drive as it no need lubricate and affected buy weather condition. chain drive have higher efficiency than belt drive. Chain drive can be components of bicycle, motorcycles, agricultural machinery and textile machinery, material handling equipment. And belt drive can be components of flour mills, coolant pump, lubricant,....

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CAD, or computer-aided design, is the use of computer software to create, modify, and analyze designs. Manual drafting, on the other hand, involves creating technical drawings by hand using traditional tools. When comparing CAD and manual drafting, CAD offers functions like three-dimensional modeling, precise measurements, and automated design modifications. It allows for faster revisions and eliminates the need for physical prototypes. However, CAD requires specialized software and training, and can be costly to implement. Manual drafting provides a tactile experience and can be more accessible in terms of cost and resources. However, it is time-consuming, less precise, and revisions can be challenging. In summary, CAD offers advanced capabilities and efficiency, but requires specialized knowledge and resources. Manual drafting is more hands-on but has limitations in functionality. The choice between the two depends on specific needs and resources.

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the solid works was first released in 1997 and it's on of the most used programs in professional settings across the globe. this CAD soft has lots of functions. firstly, it's used to sketch out ideas. Besides it can be used to experiment with features and dimensions. Moreover, the engineers can use it to produce models and detailed drawings. Solid works has many advantages. the first, it is easy and intuitive to use from the beginning. Secondly, it's easy to use for 3d modelling and to create parts ,add them to assemblies and create drawings. however has many disadvantages. First and foremost, it is expensive. next it contain some unnecessary features from the common user. in conclusion, i think solid works is a good choice due to its functions and advantages.

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A check valve is a device used to prevent back flow in a piping system. It is commonly used for water, gasoline, compressed air, and heat. It is typically made of cast iron. Here are the steps to make a check valve. In the first step, the part is cast. During this process, hot liquid metal is poured into a container and then cooled to form the correct shape. Next, the cast iron is machined on a lathe to remove excess material. After that, holes are drilled on the surface of the material using a drill. Once the drilling is complete, the material is coated with paint. When the paint is dry, the parts are assembled together using nuts and bolts. The final step is inspection. The work is carefully checked to ensure that the part has been manufactured correctly.

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As far as I know, plastic is synthetic materials that use polymers as a main ingredient . Nowadays, many products are made of plastic such as food containers and machine parts. Plastic is versatile ,lightweight, durable and some kinds of plastic are safe. there are many advantages of plastic. one of them is that it's convenient and lightweight so it's often used to make shopping plastic bags and plastic bottles. Another benefit is that it's cheap so it's used for making packaging and wrappings. A huge pro is that it's durable and resistant to all kinds of adverse outside factors such as heavy rain ,storms. What I like most about it is that reusable. However, using too much plastic everyday, people may face with different problems. First of all, plastic hurt the environment. Moreover it is not biodegradable and recycled. Plastic has many applications. In the past 100 years ago, manufacturers could produce modern synthetic plastic. Now , manufacturers can plastic into a variety of complex shapes. in the future we will save money and efficiency by using smart plastic coatings on manufacturing components. In conclusion ,plastic is one kind of useful materials for manufacturing products

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As far as I know, There are 7 types of plastic with different uses and features including: PET, HDPE, PVC, LDPE, PP, PS, and OTHER PLASTIC. The first one is PET. Its code is number 1. It is strong and recyclable. We use PET to make produce manufacture food and drink packaging. The second one is HDPE. Its code is number 2 . It is hard, resistant to impact, subjected to high temperatures, recyclable. We use HDPE to make grocery bags, milk jugs, recycling bins, agricultural pipes, playground equipment, lids, and shampoo bottles. The thirdly one is PVC/V. Its code is number 3. It is versatile and hardly recyclable. We use PVC/V to make rigid form: building and construction industry to produce door and window profiles and pipe. The fourthly is LDPE. Its code is number 4. It is flexible, odorless, transparent, recyclable. We use LDPE to make plastic bags, six-pack rings, various containers. dispensing bottles, plastic wraps. The fifthly one is PP. Its code is number 5. It is hard, sturdy, resistant to fatigue. We use PP to make Car parts, thermal vests, yogurt containers, and disposable diapers, hinges. Next, it is PS. Its code is number 6 . It is beverage cups, insulation, packing materials to egg cartons and disposable dinnerware. We use PS to make highly inflammable but dangerous as it can leach harmful chemicals, especially when heated. Finally, some other plastics cannot be recycled. It can be used for Lenses for sunglasses, sport and safety goggles, mobile phones and compact-discs (CD).

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As in the figure, this is the process of injection moulding of plastic. there are seven step in the process :

the first, pellets of plastic are fed from the hopper into a cylinder.

The second, pellets are pushed along the cylinder by rotating screw and heat.

The third, screw stops rotating and then a ram in front of the screw moves straight forward.

Next soft ,warm plastic is pushed toward a nozzle by the ram.

Next, plastic is injected through the nozzle into a shaped cavity between two halves of a mould.

Beside, plastic is cooled with the mould and becomes hard in side the cavity when the molten material is shrinking inside the mould due to cooling the screw continuously forces moten material into the cylinder and mould for replenishment,

Finally, the mould opens and cold hard solid plastic shape is ejected.

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The name of the machine tool is lathe. It helps us accurately machine different shapes and sizes. The main function of a lathe is to turn workpieces, allowing the creation of cylindrical shapes, such as shafts and bars. We should check water line pressure gauges daily to ensure there is enough cooling water when convenient. We should clean the chip filter daily to avoid clogged chips. We should warm up spindle - low speed for five minute daily to lathes work better. We should check all filters weekly so that the lathe does not become clogged during operation. We should check the coolant level weekly to ensure there is enough coolant to prevent the machine from overheating. We should check the oil and increase the oil level weekly so that the machine operates to reduce friction between machine parts. We should check the drive belt semi-annually to keep the machine running smoothly and avoid broken belts. we can test the spindle semi-annually to make the lathe work correctly.

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Plastic injection molding can encounter several typical problems, including short shots, voids, and sink marks. Short shots occur when there isn't enough plastic injected into the mold, often due to low injection pressure or inadequate venting, which prevents air from escaping. To resolve this, manufacturers can increase the injection pressure, enhance the mold temperature, and ensure proper venting to allow air to escape easily. Voids are caused by plastic shrinkage during cooling, leading to holes in thick sections. Solutions include reducing wall thickness and slowing the cooling rate to minimize shrinkage. Sink marks result from high internal stress and insufficient surface rigidity. To address this, increasing holding pressure and time, as well as optimizing wall thickness, can help maintain the part's integrity. By implementing these solutions, manufacturers can improve the quality and consistency of their molded products.

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The name of the machine tool is lathe. It helps us accurately machine different shapes and sizes. The main function of a lathe is to turn workpieces, allowing the creation of cylindrical shapes, such as shafts and bars. there are some kinds of maintenance work and their schedule for the chosen machine tool.

The first, we should check water line pressure gauges daily to ensure there is enough cooling water when convenient.

The second, we should clean the chip filter daily to avoid clogged chips.

The thirst, we should check all filters weekly so that the lathe does not become clogged during operation.

Next, we should check the coolant level weekly to ensure there is enough coolant to prevent the machine from overheating and check the oil and increase the oil level weekly so that the machine operates to reduce friction between machine parts.

Finally, we should check the drive belt semi-annually to keep the machine running smoothly and avoid broken belt.