Plaster molds, Other Engineering

Assignment Help:

           Plastic molds are made of plaster of Paris (gypsum) or calcium sulphate, talc and silica flour is added in the plaster of Paris to improve strength and to control the time required for the plaster to set. These ingredients are mixed with water and the resulting slurry is poured over the pattern.

           The plaster sets within 15 minutes usually. After the plaster sets, the pattern is removed and the mould is dried at 120°C -260°C to remove the moisture. The mould halves are assembled to form the mould cavity and are preheated to about 120°C. The molten metal is then poured into the mould.

           Patterns for plaster moulding are generally made of Aluminum, thermosetting plastics, brass or zinc alloys. Wood patterns are not appropriate for producing a large number of mould because they are repeatedly in contact with the water based plaster slurry.


Related Discussions:- Plaster molds

Architecture.., draw folded plate roof structure on multi purpose hall?

draw folded plate roof structure on multi purpose hall?

Skin-core debonding in sandwich structures, If the skins are peeled from th...

If the skins are peeled from the core, a sandwich structure loses its strength and stiffness. This can occur under - wave-slamming in fast ferries - rapid depressurisati

Edc, Combination clipper

Combination clipper

Welding techniques - plasma arc welding (paw), Plasma Arc Welding (PAW) is...

Plasma Arc Welding (PAW) is a special form of gas tungsten arc welding in which constricted plasma arc is directed at the weld area. In PAW, a tungsten electrode is contained in a

Vacuum investment casting , Vacuum Investment Casting : TITANIUM INVEST...

Vacuum Investment Casting : TITANIUM INVESTMENT CASTING uses lost-wax investment tooling to cast intricate shapes in titanium, zirconium and their alloys. A wax pattern is coa

Thin-film ic, THIN-FILM IC: Unlike the monolithic IC's, which are forme...

THIN-FILM IC: Unlike the monolithic IC's, which are formed within a semiconductor material (substrate), the thin-film circuit is formed on the surface of an insulating substrat

Arinc decoding word, how to decode arinc 429 words and send result to pc by...

how to decode arinc 429 words and send result to pc by rs232 bus

Control surfaces , Control Surfaces  As with a flight control system...

Control Surfaces  As with a flight control system, a guidance algorithm uses control surfaces to control the behaviour of an airframe.         - Rudder, ailerons, elev

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd