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Dikirim pada 31 Mei 2014 di Teknologi

In the metal casting process , there are several steps that must be undertaken to produce a mold of metal products . Prior to the casting process , first we need to know the sense of casting itself. Casting is a manufacturing process of the workpiece metal , by heating the metal to melt or melt which is then poured into the mold . Materials - materials that will be melted metal is heated in the kitchen heating up to a certain temperature to melt or fuse .( proses pengecoran aluminium )

In the casting process , there are three steps that must be done , namely : preparation tools and materials ; casting process and evaluation . What is meant by the evaluation here is an evaluation of the workpiece printout , the likelihood of defects on the printout objects . Here's a brief description of the three stages ,
First , the preparation of tools and materials . Tools and materials should be prepared , namely ,

a. Sand to mold . In the casting process , sand is used to make a mold of the workpiece to be made . The sand used is not arbitrary , but rather should be tested first to determine the desired characteristics in the casting process . Sand used should have the following characteristics :

Ø The sand must be permeability . Namely , the sand is able to have an air gap or out when the sand is compacted and get the pressure of the molten metal is poured in sand molds . When the molten metal is poured into a sand mold , will provide air pressure to exit , if the air can not escape through the gap - a gap of sand , it can cause defects in molded articles.

Ø The sand should have a high melting point . The liquid metal is poured into a sand mold , has a high temperature , if the sand did not have a high melting point (lower than the melting point of the metal ) , it will also dissolve the sand mold with molten metal is poured . Initially dense sand mold with molten metal will dissolve , so it can cause defects on the printout .

b . Setting up the pattern of the workpiece ( artificial objects ) . The pattern of the same object made ​​with the workpiece to be printed , but the pattern is made larger in size about 5 % of the size of the object to be created . For example , if we are going to print the object size is 10 mm in length , then the pattern is made of 10.5 mm in length . This is done to avoid shrinkage on casting the result object . The pattern of mock objects can be made from metal , wood or plastic . However , of each - each material has its advantages and drawbacks of each - each . For pattern made ​​of wood and plastic , the manufacturing process easier and cost of manufacture was also cheaper . However , a pattern made ​​of wood or plastic can be used for the production of objects in relatively small quantities or non- bulk . It is caused when a pattern is pressed on the sand by being hit , then this pattern will be damaged or broken , due to the less powerful . While the pattern is made ​​of metal , making the process a little more complicated and somewhat expensive biayannya . However , the pattern is made ​​of metal can be used in a longer period of time , usually for mass production , because the pattern of stronger metals compared with patterns made ​​of wood or plastic .

c . Setting up the framework of the mold . Framework of this mold is made of wood board , which consists of the cup and drag . Cup is the top board , while the drag is the bottom board . On the outer side , between the cup and given the drag lock , with a view to avoiding terjadiya or shearing motion between the cup and drag . If the order is shifted when the cups are connected ( stacked ) on top of the drag , the sand mold in order to be broken .

d . Setting up a kitchen heater or furnace . Kitchen heater serves to melt the metal to be printed . The kitchen consists of a heating furnace ( crucible ) , and kilns . Fuel used for combustion processes a wide - range , there is the use of electric power , the system resembles an electric iron , and there is also that use fuel oil and gas as fuel .

( Read: teknik pengecoran aluminium )

e . Setting up the metal to be melted material . Metal smelting can be done for a wide - range of metals, such as iron ; steel ; aluminum ; steel copper alloy ( bronze , brass , bronze, aluminum ) ; light alloy ( aluminum alloy , magnesium alloy ) ; as well as other alloys such as zinc alloy , Monel ( nickel alloy with a bit of copper ) , hasteloy ( alloys containing molybdenum , chrome and silicon ) .
The second stage , which is a metal casting . At this stage of things to do are :

a. Making molds objects to be printed on the sand . Done by compacting the sand in order to mold , pressing the sand which had previously been planted mock object pattern . Sand pressed and beaten so dense , so the sand mold is not damaged and come late when molten metal is poured .
b . Combining cup and drag , with a note and drag cup position - should be appropriate and fitting should not be shifted .
c . Making inlet for pouring molten metal in sand molds .
d . Metal smelting process . Metal - metal will be melted put in the kitchen heating , and heated to a certain temperature , the metal hinga really - really fused or melted .
e . Pour the molten metal into sand molds previously created through inlet . When pouring the molten metal , do not get too high because of the mold sand can cause the temperature of the molten metal is reduced .
f . Let the hardened molds , wait for about 10 to 15 minutes , depending on the major large - size and thickness - thin objects are created .
g . Unloading of sand mold frame , grab objects and clean sand casting results are still attached , then cut the inlet where the fluid infusion and puree with garinda .

At the final stage of the casting process is evaluation . Evaluation here the intention is to analyze the results of casting workpiece . That needs to be analyzed is the occurrence of defects that may occur during the casting process . The process is observed object casting the results , looking for defects that occur , seek the cause of defects that occur during the process pegecoran , and provide closure to handle it. This evaluation is done to be used in anticipation of the next casting process in order to avoid further error or defect in the object casting results .

source:http://hmmftum.blogspot.com/



Dikirim pada 31 Mei 2014 di Teknologi
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