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.

 

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.

 
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.

 

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.

 

 

 

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.

 

 
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.

 

 

 

 

 

- 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.

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

 

 
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.