What is Moulding?
[[File:Bronze Age spear tip mould IMG 5123.jpg|thumb|right|alt=|A mould made of stone from the [[Bronze Age]]. It was used to make [[spear]] [[blade]]s. The molten metal is poured into the hollow part, and when it hardens it is set in the shape of a blade.]] '''Moulding''' (or '''molding''') is the [[Shape|shaping]] of [[raw material]] using a solid frame of a particular shape, called a pattern. It is a process used in [[manufacturing]]. A '''mould''' is a hollow [[container]] that will hold the [[liquid]] material until it turns [[solid]]. The liquid hardens or sets inside the mould, adopting its shape. Materials commonly used in moulding include [[plastic]], [[metal]], [[glass]] and [[ceramic]].<ref>{{Cite web|title=Moulding Process - an overview {{!}} ScienceDirect Topics|url=https://www.sciencedirect.com/topics/engineering/moulding-process|access-date=2021-07-20|website=www.sciencedirect.com}}</ref> [[Tyre]]s are made using moulds, where the molten [[rubber]] is poured into the mould and then left to set. Moulds can vary greatly in size. They are usually made of hardened [[steel]] which can resist [[Wear (erosion)|wearing]]. == Types of moulds<ref>{{cite web |last1=Singh |first1=Veer |title=Types of mould |url=https://www.slideshare.net/veerG2/types-of-mould |website=Slideshare |accessdate=12 August 2021 |date=6 June 2017}}</ref> == === Compression === Compression moulds work by taking the empty mould and placing a piece of unshaped rubber inside. The mould is then pressed shut using high heat and pressure forcing the rubber to liquify and flow into the recess created for the part while excess rubber is forced into the moulds dump groove. It is important when making a mould to keep in mind that when the part cools it will shrink slightly. === Injection === Injection moulds work under the same principle as compression moulds except that instead of pressing the mould together on the rubber the mould is first closed and the liquid rubber is then injected into a fill hole drilled into the mould. This is used