Moldmaking Presentation

Molding – is the process of manufacturing by shaping pliable raw material using a rigid frame or model called a pattern.
-Mold making goes back since the earliest civilization (6,000 years ago)
-It is the oldest form of manufacturing in history. Mesopotamians used abode bricks to create their ziggurats. Wood was used to make molds.
-Early people didn’t pour the clay like we do today. They force it in the mold by “dashing” it. (Taking clots of clay/mud rolling in sand).
-Early civilizations used molds to cast bronze and copper weapons, statues, small idols
- Different kinds of molds: Compaction plus sintering, Injection molding, Compression molding, Transfer molding, extrusion molding, blow molding, rotational molding, thermoforming, vacuum molding, laminating, expandable bead molding, vacuum plug assist molding, pressure plug molding, matched mold.
- Sintering is a method for making objects from powder,. by heating the material in a sintering furnace[1] below its melting point (solid state sintering) until its particles stick to each other. Sintering is traditionally used for manufacturing ceramic objects, and has also found uses in such fields as powder metallurgy.
Injection molding is a manufacturing process for producing parts from both thermoplastic and thermosetting plastic materials. Material is fed into a heated barrel, mixed, and forced into a mold cavity where it cools and hardens to the configuration of the mold cavity. (small part, to big car parts)
Compression molding is generally preheated, is first placed in an open, heated mold cavity. The mold is closed with a top force or plug member, pressure is applied to force the material into contact with all mold areas, while heat and pressure are maintained until the molding material has cured. Compression molding is a high-volume, high-pressure method suitable for molding complex, high-strength fiberglass reinforcements.
Transfer molding, like compression molding, is a process where the amount of molding material (usually a thermoset plastic) is measured and inserted before the molding takes place. The molding material is preheated and loaded into a chamber known as the pot. A plunger is then used to force the material from the pot through channels known as a sprue and runner system into the mold cavities. The mold remains closed as the material is inserted and is opened to release the part from the sprue and runner. The mold walls are heated to a temperature above the melting point of the mold material; this allows a faster flow of material through the cavities.
Extrusion is a process used to create objects of a fixed cross-sectional profile. A material is pushed or drawn through a die of the desired cross-section. The two main advantages of this process over other manufacturing processes are its ability to create very complex cross-sections and work materials that are brittle, because the material only encounters compressive and shear stresses. It also forms finished parts with an excellent surface finish.[1]
Blow molding, also known as blow forming, is a manufacturing process by which hollow plastic parts are formed. It is a process used to produce hollow objects from thermoplastic. The basic process has two fundamental phases. First, a preform (or parison) of hot plastic resin in a somewhat tubular shape is created. Second, a pressurized gas, usually air, is used to expand the hot preform and press it against a mold cavity. The pressure is held until the plastic cools.
- Most liquid soft drink bottles are made of resin called polyethylene through a process called blow molding.
Thermoforming is a manufacturing process where a plastic sheet is heated to a pliable forming temperature, formed to a specific shape in a mold, and trimmed to create a usable product. The sheet, or "film" when referring to thinner gauges and certain material types, is heated in an oven to a high-enough temperature that it can be stretched into or onto a mold and cooled to a finished shape.
Rotational molding, also known as rotomolding, is a molding process for creating many kinds of mostly hollow items, typically of plastic. A heated mold causes the material within to melt and form a puddle at the bottom of the mold cavity. The mold is then slowly rotated (usually around two perpendicular axes) causing the melted material to flow and stick to the walls of the mold. In order to maintain even thickness throughout the part, the mold continues to rotate during the cooling phase.
-Many foods, like lollipops, gummies, and etc, are made from two part molds. The molds can be made from hardened plastic, metal, or even plaster. Gummy bears are made from plaster molds surprisingly.
-Numerous everyday objects are created from molds: plastic toys, coffee mugs, toothbrushes, soap, toilets, sidewalks, silverware.
-Molds don’t always have to be made up of metal and plastic; they can be made from gelatin, or chocolate!

http://www.moldmakingtechnology.com/articles/0807profile.html
http://digitalhistory.wikispot.org/FabWiki_Moldmaking_and_casting
http://history-world.org/sumeria.htm
http://www.nlcs.k12.in.us/oljrhi/brown/bricks/
http://en.wikipedia.org/wiki/Mold_making