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

Wire drawing, Wire Drawing involves pulling the metal through a die by mea...

Wire Drawing involves pulling the metal through a die by means of tensile force applied to the exit side of the die.          A typical wire drawing operation is shown in fig.

Inner rooms - means of escape, Inner rooms - means of escape: I nner...

Inner rooms - means of escape: I nner rooms are rooms from which the means of escape require people to travel through another room (called the access room).  These are comm

Electronics devices and circuits, With the help of circuit diagram and the ...

With the help of circuit diagram and the waveforms,explain the working of a negative clipper with positive biasing voltage.also explain the Same concept in series clipper circuit

Java, I''m trying to figure out how to use a for and while loop to: print e...

I''m trying to figure out how to use a for and while loop to: print each word found in 4 columns across the output page, in the order they were found. This means you must print the

Simulation, A system is a walk-in medical clinic; a simulation is used to d...

A system is a walk-in medical clinic; a simulation is used to determine staffing levels. Under what circumstances would it be appropriate to use a terminating simulation or a stead

Chemical engineering project, Hello, I have a chemical engineering project...

Hello, I have a chemical engineering project and I need help.

Series of cash flows in economical engineering, Series of Cash Flows M...

Series of Cash Flows Most engineering economic analysis involve more than a single return occurring after the investment is made. In such cases, the present worth or the futur

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