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Write a paragraph (120-140 words) to present maintenance schedule of machine tools using the following suggested questions.

What is the name of the machine tool?

What are its features/ functions?

What are some kinds of maintenance work and their schedule for the chosen machine tool?

Why do we need to carry out these kinds of maintenance work?

CNC machine is one of the important industrial machine tools. Because of the high cost, workers have to maintain it regularly. There are many components which need maintaining. Firstly, we have to check the hydraulic pressure daily to make sure it’s at 4.5 MPa. Secondly, it is also necessary to clean off the window of the door and the light every day. CNC machine has a cooling system so make sure the cooling unit level is at the right operating level. We should check this system once a week. Every month, we need time to have the radiator cleaned and make sure the radiator fins are straight. Next, have the lubrication unit drained and cleaned out, then add fresh way lube semi-annually. Lastly, please have the spindle checked for radial and end play every year.

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Write a paragraph (120-140 words) about typical problems typical problems of plastic injection moulding and explain causes and solutions to these problems.

Sink marks are small recesses or depressions in an otherwise flat and consistent surface of a molded part. These can occur when the inner part of a molded component shrinks, pulling material from the outside inward.

Causes and prevention of sink marks

Sink marks are similar to vacuum voids but are reversed in cause and effect. Rather than the material cooling too rapidly near the exterior of the part, the material cools too slowly. The resulting shrinkage pulls the outside material inward before it’s had a chance to adequately cool, leading to a depression. As with voids, sink marks are more likely to occur in thicker parts of a component. Here are some steps you can take to prevent this defect:
+ Increase holding pressure and time to allow the material near the part’s surface to cool

+ Increase cooling time to limit shrinkage

+ Design your mold with thinner component walls to allow for faster cooling near the surface

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Write a paragraph (120-140 words) to describe the following plastic moulding process using the diagram below

Suggested questions:

- What is the name of process?

- How many steps are there in the process? What are they?

- Describe each step.

This is the process of injection moulding of plastic. There are six steps in the process. The first, pellets of plastic are fed from the hopper into a cylinder. Then, the pellets are pushed along the cylinder by a rotating screw and heated to become molten plastic. After that, the soft, warm plastic is pushed toward a nozzle by the ram. The fourth step is soft plastic is injected through the nozzle into a shape cavity between the two halves of a mould. Next, the plastic is cooled by the mould and becomes hard inside the cavity. Finally, the mould opens and the plastic product are ejected.

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Write a paragraph (120-140 words) about your understanding of plastic.
You should mention the seven types of plastic and their codes, a common type of plastic with its properties and its applications.

As you 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 recycable. We use PET
to make/ produce/ manufacture food and drink packaging.

- The second one is HPDE. It is hard, resistant to heat, recyclable. We use HDPE to make procery bags, milk jugs, recycling bins, agricultural pipe, playground
epuipment, lids, and shampoo bottles

- Finally is PVC. It is lightness, durability, and easiness of process ability,
hardly recylable. We use PVC to make building and construction industry to
produce door and window profiles and pipes with rigid PVC. And use flexible PVC
to plumbing, writing, and electrical cable insulation and flooring.

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Write a paragraph (120-140 words) about basic information of plastic (qualities and uses of plastic) using the following suggested questions.
·        What is plastic?
·        What are the properties of plastic?
·        What could/ couldn’t people do with plastic in the past? What can/ can’t people do with plastic now? What is the future of plastic?
·        What are the advantages/ disadvantages of plastic?

As far as I know, plastic is a synthetic materials that use polymers as a main ingredient. Plastic is able to be moulded or shaped to any forms. 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. Plastic brings us a great number of benefits. The first pro is that it’s convenient.Nowadays, manufacturers can be moulded plastic into a variety of complex shapes. Plastic can be used in manufacturing to help designers reduce weight in aircraft. In the future, we will save money and increase efficiency by using smart plastic coatings on manufacturing components. Soon it will be possible to use eco-friendly bioplastic in a wide range of applications in electronics, automotive and other fields. In the near future, we will be able to make plastic from any kind of plant materials.

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Write a short paragraph (120-140 words) about different kinds of bearings using the following suggested questions.

How many kinds of bearings do you know?

What are they used for?

What are their components?

What are their main features?

What are their applications?

There are 2 kinds of bearings: rolling contact bearings and journal bearings. Rolling contact bearings used rollers to support loads. There are 4 types of rolling contact bearings: ball bearings, straight roller bearings, tapered roller bearings and thrust roller bearings. Ball bearings use spherical rollers. They are to support radial and axial motion. Straight roller bearings use cylindrical rollers. They can be used to support radial motion. Tapered roller bearings use conical rollers. They serve to radial forces and moderate thrust forces. Thrust roller bearings use barrel-shaped rollers. They are for supporting thrust motion. Journal bearings have no rolling parts. They shaft rotates inside a lubricated tube instead. Bearings are very important to the mechanical industry and are widely used in the world.

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Look at the diagram, write the manufaturing process of a check valve (120 - 140 words).
The check valve is made of cast iron.the first step is casting. This step means that hot liquid material is poured into a container and cooled to make the correct shape. In the next step, after materials are turned on a machine called a lathe, part of the materials is remaved to make the correct shape. Next, holes are made using a drill. After the drilling proccess, the next step is painting process. In this step, a surface is covered with paint. Next, pieces of materials are joined together using a nut and a bolt. The final step, a product is checked carefully.

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Write a paragraph (120 - 140 words) to describe a specific CAD program using the following suggested questions.
· What is the name of the CAD program?
· What are its features?
· What are its functions?
· What are its advantages and disadvantages?

The solidworks was released for the first time in 1997. It can be one of the most used programs in profressional settings across the globe. The function of the solidworks is sketch out ideas and produce models and detailed drawings. Next, the CAD program has a lot of advantages. Firstly, it is easy and intuitive to use from the beginning. Next, it can be use for 3D modelling easily. Besides, it’s quite expensive and contain some unnecessary features for the commom user. Genetal, Solidworks is always one of the best CAD software at present.

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Write a paragraph (120 - 140 words) to compare two types of drives using the suggested questions below.

What are two types of drives?

What are the functions of each type?

What are the differences between them (materials, operation, slippage, efficiency, maintenance, etc.)?

What are some applications of each type?

Two types of drives are belt drive and chain drive. Both belt drive and chain drive can be used to transmit motion and power.  Chain drive made of metal, while belt is often rubber, plastic with a number of links. The operation of belt drives is different to that of chain drives as it can reduce noise and vibration. Slippage occurs in belt drive. Chain drive is different from belt drive because it doesn’t often occur. Efficiency of belt drive is low because of frictional loss while the efficiency of chain drive is high. Belt tension of belt drive is affected by atmospheric condition and temperature. Unlike belt drive, chain drive isn’t. Belt drive requires frequent re-tension. Chain drive is different from belt drive because it requires regular lubrication. The belt drive is used in coolant pump and lubricant pump. Chain drive applicable to bicycle and motorcycles.

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Write a paragraph (120 - 140 words) about different types of gears using the following suggested questions.

What is a gear?

What are its functions?

How many common types of gears are there? What are they?

What are their features?

What are their applications?

Gear is a machine component with teeth. Gear teeth mesh together to transmit torque. They are used to reduce or increase the speed of a motion and they can also change the direction of motion. The simplest and most common is the spur gear with teeth projecting towards or away from center. Spur gears are used in low-speed applications, it cannot control noise at high speed. Next, helical gear have their teeth cut in a spiral shape. Helical are used in high-speed applications, it can run smoothly and quietly and control noise. Worm is a type of gear with one continuous tooth. A worm pairs with a worm gear, which help reduce speed. Rack and pinion gears include a circular gear engaging a linear gear, which help convert rotational motion into linear motion. Finally, Bevel gears have a conical form and can be used to transmit rotational power through shafts at an angle, normally 90 degrees.

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Write a short paragraph (120-140 words) about different kinds of couplings using the following suggested questions.

How many kinds of couplings do you know?

What are they used for?

What are their components?

What are their main features?

What are their applications?

There are 2 kinds of the couplings: rigid coupling and flexible coupling. Coupling is a machine component which connects two shafts together to transmit power. Rigid couplings are used for aligning the shafts with each other. Sleeve-style couplings are the most common rigid couplings. If you use a sleeve-style coupling when shafts are not in perfect alignment. It will break. Flexible couplings can help reduce noise and unwanted vibrations. A beam coupling is a common kind of flexible coupling. It is cut in a spiral shape. If you use a beam coupling when there is a perfect alignment. It can't maximize the efficiency and effectiveness of machine. Couplings are very important to the mechanical industry and are widely used in the world.

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Write a paragraph (120- 140 words) about how to make an effective presentation using the following suggested questions:

What is the basic structure of a presentation?

What should you do before the presentation?

What should and shouldn’t you do during the presentation?

What should and shouldn’t you do after the presentation?

The basic structure of a presentation include introduction, development, conclusion. Before the presentation, you should write down the presentation. Next you need to practice and turn of the phone before presenting. During the presentation, you should use gestures and body language to express ideas. Next, you will need to make eye contact, look at the audience, do not look at the floor or ceiling and do not just look at the paper and read. You should have movements to interact with the audience. Finally, after the presentation, you should thank the audience after they ask you a question and try to answer the audience question. Presentation is a skill that can be learned day by day to improve.

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Write a paragraph (120 - 140 words) to compare CAD and manual drafting using the suggested questions below:
· What is CAD and manual drafting?
· Compare CAD and manual drafting (functions, advantages and disadvantages).
Manual drafting is all about creating this technical drawing by hand and using pencil, pen, paper, ruler. Manual drafting is not only cheap, but also show the creativity of the design engineer with the project. Its disadvantage is that it is very waste time and difficult to change. Unlike manual drafting, CAD is a form of industrial arts that involves using computer to create technical designs. With CAD, designers don't need to use paper to put their ideas into shapes. CAD help turn designs into models easily. CAD software tools allow to view the object from any angle, even from the inside looking out. CAD can be used to create two- or three-dimensional diagrams by designers. The disadvantage of CAD software is that the cost of use and maintenance is quite large.