The second kind is roller bearings. It has rollers, rings, and a cage. It can carry heavy loads. It is used in conveyors and gearboxes. The third kind is journal bearings . It has a shaft and a smooth surface. It works with lubrication. It is used in engines and turbines. These bearings will support our daily work.

I bought three kinds of couplings: rigid coupling, flexible coupling, and beam coupling. I bought them yesterday at a machine shop near our company. The rigid coupling has two sleeves and bolts. Its function is to join two shafts with no movement. It is used in simple machines.

The flexible coupling has two hubs and a rubber part. Its function is to allow small misalignment. It is used in pumps and conveyors. The beam coupling has one piece of metal with spiral cuts. Its function is to allow angle and parallel misalignment. It is used in robots and CNC machines.

Sincerely, Quy

Firstly, the function of BD is to transmit power from one shaft to another by means of pulleys, while CD is used to transmit power between parallel shafts. Secondly

BD is made of rubber, plastic, but CD is made of metal. Thirdly, BD is different from CD because BD can reduce noise and vibration. Besides, it doesn’t need to lubricate. Moreover, it requires more tension. While CD is not affected by atmospheric condition, BD is affected by weather condition. CD has higher efficiency than BD. The applications of BD are flour mills, coolant pump, lubricant pump, AC, cam shaft, alternator, lathe machines and lots of other machines, belt conveyors. However, CD are used in bicycle, motorcycles, agricultural machinery and textile machinery, material handling equipment.

First, the aluminum is melted and poured into a mould to form the basic shape.

When the metal cools down and becomes hard, it is removed from the mould and milled to make the surface flat.

Then, a hole is drilled in the center so it fits the machine shaft.

After that, the edges are polished to remove rough parts and make the wheel smooth.

As the final step begins, the product is inspected carefully by the worker to make sure there are no defects.

Finally, the aluminum wheel is completed and ready to be used in production.

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

Second, the pellets are pushed along the cylinder by a rotating screw and heated.

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

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

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

Besides, the plastic is cooled within the mould and becomes hard inside the cavity. While the molten material is shrinking inside the mould due to cooling, the screw continuously forces more molten material into the cylinder and mould for replenishment.

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