Plastics quizz

Thermoplastics

soften and melt heated

Thermoset plastics

harden when heated

PET/PETE polyethylene terepthalate (1)

Mainly used in all sorts of bottles and ziploc bags. One use items.

PEHD polyethylene high density (2)

milk, juice, detergent, shampoo bottles. Little bit of a nicer material.

PVC polyvinyl chloride (3)

can be used for giftcards, piping, vinyal flooring, some food packaging. Can be flexabile or rigid.

PE-LD polyethylene low density (4)

lots of bags. grocery bags, bread bags, newspaper bags, bags bags bags.

PP polypropylene (5)

super common for anything food related. tupperware, food containers, straws, anything food

PS polystrene (6)

Styrofoam, lots of food packaging containers, takeout lefts overs, disposable food things

other (7)

this is a catch all for other types of plastic and mixes of plastics. Car headlights, CDs, and squeeze bottles

PMMA polymethyl methacrylate

plexiglass. a cheaper more resilient alternative to glass. acrylic nails, phone screens, medical devices.

PBT polybutylene terephthalate

very similar to PET off white-white polyester. often used in food proccessing and sometimes electrical devices and machinery

PC Polycarbonate

naturally transparent amorphous thermoplastic. used in protective eyewear, greenhouses, exterior lightening fixes .

PA6 PA66 -Nylon 6 & 6-6 Polyamide

hard and resist, hammer heads, gear weels,cutting boards.

POM polyoxymethylene

can take moisture well and can be made easily, ball bearings, ski bindings, fasteners.

ABS Acrylonitrile Butadiene Styrene

very tough, high gloss, plastic toys like legos, vacum cleaners, printers.

injection molding

mold is closed, plastic is injected in, plastic cools, part gets ejected

parting lines

lines on the side of an object where the sides of the mold meet

gate marks

where the plastic was injected. Will be sanded if it is nicer object, otherwise there is usually a bump

sink marks

when cooling the plastic will sink sometimes and there will be some dent

pin marks

marks from where the mold was being held, leaves small circles

knit lines

a line where the object was knit together by welding or other

flash

excess material that flows out due to the mold not being sealed, usually trimmed

clamping unit

the part of the mold that holds it closed

injection unit

part of the machine that injects the plastic into the mold

barrel

a heated cylinder where the plastic pellets get melted

screw

a rotating piece in the machine where the plastic pellets are mixed and melted

plasticizing

the process of converting the pellets into a suitable moldable state

mold

the piece that holds shape that the plastic takes

cavity

hollow part of the mold that shapes the exterior shape

core

forms the interior features of the part - typically fits inside the cavity

sprue

the channel that the molten plastic goes through the injection unit into the runner system

runner

the passages within the mold that direct the plastic to the part

cooling time

the time in which the part is cooling and solidifying

cycle time

the full time it takes for the process of making the part

draft angle

an angle applied to vertical surfaces that allow for easy injection

undercut

a feature of a part that makes it hard to injection into. special techniques have to be used.

blow molding

used to make bottles. the plastic is cut and put into the mold. strong air is then blow into the mold causing the bottle to expand and take the shape of the mold

rotation molding

plastic is heated inside the mold. The mold rotates on two separate axis’ to make sure the plastic is even coated and spread throughout. Hollow durable and lightweight. Used to make things like playground equipment, bins, buoys, and more.

vacuum molding

similar to injection molding but typically used for prototypes or small parts. The vacuum part draws the liquidized plastic into the mold and is also used to eject the piece

reaction injection molding

two liquid polymers are injection into the same mold and are mixed together. the reaction forms the final plastic piece. the items are typically made for the automotive or medical industry.

dip molding

the mold gets dipped into the melted plastic and it creates a plastic shell around the mold that can be removed. It is used to create handles and similar things (and sometimes containers)

multishot injection molding

two plastics are injected at the same time, one is being injected over a previously molded part. the single part has been overfolded by the other plastic and the cycle can continue. common uses are toothbrushes, and certain multiplastic tools.

in-mold decoration

something that is placed into the mold before plastic is inserted. this can be to give texture or any extra detail.

compression molding

similar to injection molding, two sides of a mold push down and the plastic is spread throughout. instead of injecting it however it is put inside the open mold and is then squished. can make handles, ashtrays, electrical and housing equipment

thermoforming

a sheet of plastic is put over the mold. the mold is then shut and you have your shape. shallow and thing walls. good for clamshell packaging, cosmetic trays, tanks, etc.