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

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

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·        Check all the running parts to make sure that they are not too tight, or loose. Bearing of headstock, longitudinal and crossfeed, tool holders, etc. would be examined and adjusted by hand or proper fitness.

·        Check the sensitivity and reliability of all manual control levers: To try the speed change rate function of headstock feeds and apron in the gearbox and inspect their starting, stopping, forwards and reverse action whether they are sensitive, reliable or not.

·        Cleaning the machine: dust, chips and other particles should be removed from sliding surface of machine to make the rotating or sliding parts performing easy and smoothly. All other static parts can be often also cleaned to avoid corrosion.

·        Check the tightness of the bolts holding the millhead in place.

·        Greasing and oiling: regular oiling should be done every day (see lubrication plan sheet) to keep the machine properly lubricated. Check the oil site gauge under the lathe chuck and add oil if the level is below the halfway point. - show the lubrication plan sheet.

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Here is the maintenance schedule of lathe machine. Lathe machine has some features are easy to ensure the positional accuracy of each processing surface, high productivity, the production cost is low, wide ranges of machine able materials. so that the machine always operates in the best condition we need to have a resonable maintenance schedule. First we should clean chip filter daily to remove dust and dirt. Secondly the oil level need to be inspected and toped up once a week to ensure engine efficiency. Last one we had better inspect spindle bearing and drive belt semi – anually. The funtion of that is to prevent slippage.

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

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

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This plastic injection moulding process consists 7 steps. First step, The pellets of plastic are fed from the hopper into a cylinder. Next, the pellets are pushed along the cylinder by a rotating screw, and heated. After that, the screw stops rotating and then a ram in front of the screw moves straight forward. In step 4th, the soft, warm plastics is pushed toward a nozzle by the ram. The soft plastic is injected through the nozzle into a shaped cavity between the two halves of a mould. Then The plastic is cooled by the mould, and becomes hard inside the cavity. Finally, the mould open and the cold, hard, solid plastic shape is ejected.

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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.

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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.

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There are typical problems of plastic injection molding: short shot, void, sink mark, flash, air trap and brittleness. Air trap occurs when the air is unable to escape from the parting surface, the ram, or the vent when the two melt fronts meet. Brittleness may cause by dry conditions are not suitable, injection temperature setting is wrong. Sink mark happens when the cooling speed is low or the shrinkage level is high. Flash occurs when the molding conditions are unreasonable. Void happens when the gate is too small. The fill speed and pressure is low may cause short shot. To solve air trap problem we should reduce thickness inconsistency and try to ensure uniform wall thickness. With brittleness problem, we should set appropriate drying conditions before injection molding. To prevent sink mark we need to increase holding pressure and holding time. Increasing the injection time and reducing the injection speed may solve flash problem…

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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.

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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.

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Plastic has seven types and they have their own codes. Plastic with code number 1  is made of  polyethylene (PET). High-Density Polyethylene (HDPE) with code number 2 is an incredible resistant resin. Code number 3 is polyvinyl chloride (PVC) that is the world’s  third-most widely produced synthetic plastic polymer. Low Density Polyethylene (LDPE) with code number 4 is a flexible , recyclable thermoplastic polymer. Polypropylene (PP) – the second-most widely produced commdity plastic has code number 5. Code number 6 is Polystyrene (PS) – a very inexpensive resin per unit weight and easy to create. And the code number 7 is others. The most plastic commonly used in daily life is PET. It holds the number q spot because of its widespread utility. PET is mostly used for food and drink packaging purposes due to its oxygen prevention. Beverage bottles are amoing the main plastic items that come for PET. Also, PET bottles are the most widely recycled plastic in the world.

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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.

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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.

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Plastic is the familiar plastic that is commonly used in daily life. Plastic is synthetic materials that use polymers as a main ingredient. Plastic is able to be moulded or shaped to any forms. Plastic is versatile because it can be shaped easily into a wide range of forms. Plastic is lightweight so it is used in manufacturing airplane interiors and exterior parts. Palstic is also durable because its has a long life compared to many products and retains their shape and strength. In the past, manufacturers could produce modern synthetic plastic but we could not mould plastic into complex shapes. Nowadays, manufacturers can mould plastic into a variety of complex shapes. In the future, with modern technology, plastic will be possible to use eco-friendly bioplastic in a wide range of applications in electronics, telecommunications, aerospace, automotive and other fields. Plastic has many advantages like convenient, lightweight, cheap, durable and resistant or reusable. But is also has some disavantages. It hurts the enviroment. it is not biodegradable and it is not recycled.

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Look at the diagram, write the manufaturing process of a check valve (120 - 140 words).Use some useful languages of sequence and the time clause when, as, before…… as followed.

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Look at the diagram, write the manufaturing process of a check valve (120 - 140 words).Use some useful languages of sequence and the time clause when, as, before…… as followed.

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The check value is made of cast iron.

First is casting. In this step hot liquid of aluminum is poured into a container and then cooled to make the correct shape.

The cast iron is then turned on the lathe to remove excessive parts.

Next, holes are made using a drill as you can see on the screen.

After drilling, the surface is paited to make it look great, the next step is punching holes.

The final step is inspection. In this step, the product is checked carefully.

This is when we make sure that the part is made properly.

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Write a paragraph (120 - 140 words) to compare CAD and manual drafting using the suggested questions below:

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Write a paragraph (120 - 140 words) to compare CAD and manual drafting using the suggested questions below:

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CAD is the creation and handling of the pictures on a computer to assist engineers in design and drafting. And Manual Drafting is the practice of creating drawings by hand with pencil or ink on a media such as paper or polyester film using drafting equipment. CAD has a quick layout of a preliminary design and necessary change. Manual Drafting can only draft single detailed drafting. CAD is used to change models faster than the other programs. Using CAD to design is faster than manual drafting. CAD is more expensive to purchase than other programs. CAD is used to turn designs into models more easily than the other programs.

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Write a paragraph (120 - 140 words) to describe a specific CAD program using the following suggested questions.

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Write a paragraph (120 - 140 words) to describe a specific CAD program using the following suggested questions.

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AutoCAD is a computer-aided design software developed by the Autodesk company. It was first released in December 1982. It allows you to draw and edit digital 2D and 3D designs more quickly and easily than you could do by hand. the main AutoCAD window consists of drawing area, ribbon pannel,  quick access button, model and layout tab,… Main features of Autodesk AutoCAD are designing 2D, 3D modeling and visualization, creating surface, meshing model, quick measuring,.. AutoCAD helps the user to develop, modify, and design better infrastructure. You can create designs quickly and easily, using the software’s easy tools to complete tasks in a fraction of the time it would take via manual drafting. AutoCAD supports documentation tools that increase productivity. It also provides solutions to implement modifications in the projects, thus reducing the time taken. However, it is very expensive to purchase. You need a expensive equipment to use AutoCad smoothly.

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

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

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There are two main types of drives - belt drive and chain drive. Belt drive is used to transmit motion and power from one shaft to another by means of friction between belt and pulleys. Chain drive is used to transmit motion and power between successive chain with sprocket special toothed wheels. Belt drive is made of rubber, plastic while chain drive is made of metal with a number of links. Belt drive can reduce noise and vibration. Unlike belt drive, chain drive causes noise and vibration. Slippage occurs in belt drive while there is no slippage occurs in chain drive. As the result, efficiency of belt drive is comparatively low while the efficiency of chain drive is high, usually above 95%. Belt drive requires minimum maintenance but chain drive requires regular maintenance including lubrication. Application of belt drive are flour mills, coolant pump, lubricant pump, AC, CAM shaft,… Chain drive is used in bicycle, motorcycles, agricultural machinery…

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

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

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A gear is a machine component to transmit power. It is the shape of a circle with teeth. Gear teeth mesh together to transmit torque. When two gears engage, they form a gear set. Gears are split into five common types. Firstly, the spur gear is the most common type of gear with teeth projecting towards or away from the center. Secondly is a helical gear, it meshes more smoothly than a spur gear. Some kind of helical gears has continuous teeth, they are called worms. A worm pair with a worm gear which is the third type of gear. The fourth type is rack and pinion, they are used to convert rotational motion to linear motion. Finally, the bevel gear is used to transmit power at angles.

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

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

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As you know, there are two main types of couplings. They are rigid couplings and flexible couplings.  Rigid couplings are used for shafts having no misalignment. The most common design of the rigid coupling is of a split configuration. The coupling is split along axial centerline. Rigid couplings are constructed of all metal materials. This allows the coupling to be used in applications that have high temperatures, high speeds, a solvent atmosphere, or high driver horsepower. It has applications such as: Mounting propellers, gears, sprockets, pulleys, gearboxes,... Flexible couplings are more commonly used to transmit driving torque between a prime mover and a rotating element of the equipment. The elastomeric flexible coupling typically utilizes a plastic or rubber element that allows for the temperature growth or axial movement. Other types of flexible couplings include limited end float, metal disk, diaphragm, and jaw- type. Flexible couplings are applied in the relative displacement between axes are kept within specified tolerances. Flexible coupling model is widely used thanks to its compact design, easy installation, convenient maintenance, small size and light weight,…

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

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

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Bearing is one of the most commonly uses in Mechanical Engineering. Bearing is divided in to 2 kinds: rolling contact and journal. Rolling contact bearings are used to support loads. They have 3 main parts: rollers, inner race and outer race. There are 4 main types of rolling contact bearings. Ball bearings use a spherical rollers to support radial and axial motion. Straight roller bearings use cylindrical rollers to support radial motion. Tapered roller bearings use conical rollers to support radial forces moderate thrust forces. Thrust roller bearings use barrel-shaped rollers to support thrust motion. The different kind of bearing is journal bearing that use a lubricated sleeve and has no rolling part.

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

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

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All presentations consist of three basic parts: the introduction, the body, and the conclusion. The presentation should include some kind of attention getter and the conclusion should sum up what you had to say. The body is the main part of your presentation. Before the presentation, you should prepare a presentation carefully. You should choose your presentation’s style, outline your presentation and practice it ahead of time. There are many things you should do during the presentation to have a good one. First, you need to make it easy for your audience to understand and respond. Then, you should smile and make eye contact with your audience. Make your gestures open and confident, and move naturally around the stage, and among the audience too, if possible. Beside, you shouldn’t put your hands on your hips and just look at the paper and read… And after the speech ends, you should thank and appreciate your audience, ask them for feedback and give them details to contact you.

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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.

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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.

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There are typical problems of plastic injection molding: short shot, void, sink mark, flash, air trap and brittleness. Air trap occurs when the air is unable to escape from the parting surface, the ram, or the vent when the two melt fronts meet. Brittleness may cause by dry conditions are not suitable, injection temperature setting is wrong. Sink mark happens when the cooling speed is low or the shrinkage level is high. Flash occurs when the molding conditions are unreasonable. Void happens when the gate is too small. The fill speed and pressure is low may cause short shot. To solve air trap problem we should reduce thickness inconsistency and try to ensure uniform wall thickness. With brittleness problem, we should set appropriate drying conditions before injection molding. To prevent sink mark we need to increase holding pressure and holding time. Increasing the injection time and reducing the injection speed may solve flash problem…