Question

Problem 3: (22%) For each of the following plastic items: 1) suggest a manufacturing process, and 2) explain what property / characteristic / design feature you think is most important.

Answer 1

a) MANUFACTURING PROCESS: Blow Moulding

DESIRED PROPERTY/CHARACTERISTICS/ DESIGN FEATURE :Easily portable, bottles make for convenient use, because they need frequent transportation and they are part of daily life so they must be easy to use.

b)MANUFACTURING PROCESS: Die-cutting of plastic frames

DESIRED PROPERTY/CHARACTERISTICS/ DESIGN FEATURE :sculpted and gimbaled nose-pads, durable hinges with self-locking screws, and flexible temples , because they should be comfortable to wear.

c) MANUFACTURING PROCESS :insulating material is added by a process of extrusion at high temperature

DESIRED PROPERTY/CHARACTERISTICS/ DESIGN FEATURE:its insulation capacity and its heat resistance should be good otherwise it will leak.

d)MANUFACTURING PROCESS:several filaments are grouped together in a process called doubling or throwing,This produces a sliver of multiple plies of filaments.The sliver is run through the rollers of a drawing machine to compress it before it is twisted into yarn.

DESIRED PROPERTY/CHARACTERISTICS/ DESIGN FEATURE:diameter and tensile strength because mostly it is in tensile loading

e)MANUFACTURING PROCESS  needles are significantly more complex and are produced directly from a die casting

for barrel and plunger One method of production is extrusion molding

DESIRED PROPERTY/CHARACTERISTICS/ DESIGN FEATURE:needles diameter

f) MANUFACTURING PROCESS  Extruded rubber seal strip production and cutting into small pieces.

DESIRED PROPERTY/CHARACTERISTICS/ DESIGN FEATURE stable dimensional accuracy because if they expand from their required dimension they are useless

g)MANUFACTURING PROCESS Rotational molding

DESIRED PROPERTY/CHARACTERISTICS/ DESIGN FEATURE should be comfortable in leisure and sport , its obvious

h)MANUFACTURING PROCESS  injection molding

DESIRED PROPERTY/CHARACTERISTICS/ DESIGN FEATURE it should have press fit it should not fall apart frequently from pen

i)MANUFACTURING PROCESS

Trash bags are made from polyethylene – a tough, light, flexible plastic used chiefly in containers, insulation, and packaging. Polyethylene got its name because it is a polymer (a type of chemical compound) of ethylene, a colorless gas used in the production of many chemicals. Polyethylene is resistant to chemicals and moisture, and has good insulating properties.Resin pellets are small, hard cylindrical shaped plastic particles. To make garbage bags, polyethylene resin pellets are poured into large hoppers, or containers used for pouring materials into a machine or opening.The resin pellets then enter an extruder – a machine that melts the pellets by heating them to a temperature between 365 and 465 degrees Fahrenheit. Once the pellets are heated and thoroughly mixed by the extruder the remaining raw plastic mixture is then pushed through a die. A die, or a special tool to cut or shape material, forms the plastic into a ring. The ring is then blown into a bubble – surprisingly elegant and shimmery, similar in appearance to a large, glistening soap bubble.The plastic tube gradually cools down. It is several hundred feet long, and it has a minimum thickness of two ten-thousands of an inch. Next, rollers collapse the bubble into a flat tube, called a film, which is easy to work with.The tube of flattened film is heat-sealed on one side. The film is perforated, then cut into bags

DESIRED PROPERTY/CHARACTERISTICS/ DESIGN FEATURE they should not tear otherwise garbage will spill

j)MANUFACTURING PROCESS Plastic is heated and pushed through a heated chamber by a screw. Molding: Plastic is forced through a die that creates the final shape of the part.

DESIRED PROPERTY/CHARACTERISTICS/ DESIGN FEATURE : it should not tear otherwise it will be a bad packaging.

k)MANUFACTURING PROCESS : thick layer of melanine powder is spread over a die which is a heating continuosly and is compressed then it takes shape of plate.

DESIRED PROPERTY/CHARACTERISTICS/ DESIGN FEATURE it should not break, it should not be temperature sensitive as it is being used in kitchen.

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