Belangrikheid vir ontgooi van ontwas

Ontgieting van ontwas is van groot belang in die beleggingsgietproses. U moet oor die nodige kennis beskik, aangesien dit die kwaliteit en samestelling van die vorm kan definieer. Daar is baie aspekte van die ontwas-tegniek.

In die loop van hierdie artikel gaan ons praat oor die ontwas van die dop. Laat ons dus begin sonder enige verdere vertraging!

Inleiding tot Dewaxing Casting

To ensure the quality of investment cast mould, it is imperative to pay close heed to the wax removing process. After all, it is among the most important step of the cost mould. Dewax can lead to a number of problems.

For instance, it can cause microcracks. After all, the de-waxed or the green shells are fragile and vulnerable before firing. To hold the components of the shells together, manufacturers either use fibers and polymers or colloidal networks.

In most cases, the manufacturers depend upon the autoclaving method for removing wax patterns. However, there are certain manufacturers that de-wax via the flash firing method. The choice greatly depends upon the manufacturer’s preferences and requirements.

Die grootste voordeel van die gebruik van stoom in plaas van die lug in die bakoond is om effektiewe en doeltreffende energie-oordrag na die koppelvlak laag was te verseker. Boonop laat die outoklaveringsmetodes die herwinning van die gesmelte was toe.

Dit verminder ook die vrystelling van besoedelende gas, veral as u dit vergelyk met die blitsvuurmetode. Daar is weinig tot geen hoeveelheid was agter nadat die outoklaaf-ontwasproses voltooi is nie. Dit lei dan tot minder produksie van as tydens die skietprosedure.

Outoklaveringsmetode

Die outoklaveringsprosedure gebruik stoom vir 'n kitsbron. Die stoom is vertroud met die dopoppervlak. Die konstante aanbring van stoom lei tot 'n verandering in die vaste was in die dop.

The wax starts to melt and at the same time, there is increased stress on the shell’s inside surface. The stress is the result of the liquid volume expansion and the phase transformation.

NOTE: It is vital to release the pressure build inside the shell due to expansion as soon as possible. Lack of pressure release would lead to the cracks in the shell.

Release Mechanism

The pressure release mechanism is simple and effective. What happens is that after the steam penetrating the shell melts the solid wax inside, the melted wax then passes into the prime coat. To enter the prime coat, the wax penetrates the shell.

The decrease in the shell stress is due to the penetration of the liquid wax into the prime coat. Likewise, the polymer present in the shell makes it robust and strong. It offers a better system for absorbing the pressure that is building up in the shell.

Prime Coat- Shell Properties

Manufacturers greatly emphasize the fact that relieving the right amount of pressure via the prime is important. However, it is important to understand that the pressure relieve should not compensate for the integrity of the prime coat nor should it have an adverse impact on the surface roughness.

To increase the shell's ability to withstand pressure, manufacturers something incorporate polymers into the prime slurry. The polymers also help absorb the wax expansion. Thus, making the shell sturdy and strong.

It is important to wet the prime coat using the liquid wax as this would ensure better shell permeability. There are several factors that influence surface wetting. For instance, the temperature, surface heterogeneity, roughness of the prime coat surface, wax liquid characteristics, and the rate of wetting.

Backup Coat- Shell Properties

In order to avoid all sorts of shell cracking, you need to pay extra attention to back up coats. After all, these coats need additional strength for the penetration of the shell cracking. The number of back up coats greatly depends upon the mechanical strength and the slurry system.

You can have as little as four backup coats or the number can go up to 12 or so. Do bear in mind that the shell thickness would lead to an increase in the heat capacity of the shell. Thicker the shell, higher its heat capacity.

Also, higher thickness requires additional steam energy to convert the solid wax within into liquid wax. Thus, you need to have a balance of the permeable shell system. Prevent the right amount of steam penetration along with good mechanical strength.

To further enhance the stability and the survivability rate, it is a good idea to add polymers to the shells.

Dewaxing Casting Properties

For the making of beleggingsgooi -pattern waxes, manufactures mainly use the microcrystalline waxes and the paraffin waxes as the base wax. They then add plasticizer, fillers, and resin. However, the decision of adding plasticizer, resin, and fillers depends upon the application type.

Each factor offers different benefits. Like, adding fillers to the wax would reduce shrinkage, it would enhance dimensional performance and result in better mechanical properties.

For the designing of wax good for autoclaving dewaxing casting, there are different parameters that hold importance. For instance, you would have to focus on the conductivity, heat capacity, melting point, viscosity, and thermal expansion.

Autoclave Dewaxing Suggestions

In most cases, the manufacturers suggest running auto-clave at least six bars in three seconds. Then allow the pressure to recover up to eight or nine bars. Do bear in mind that there should be a steady increase in the steam pressure along with the simple pressure.

'N Hoër drukverminderingskoers kan 'n nadelige uitwerking hê op die vorms se druksakke sowel as die geval van die kondensstoom. Dit kan dan lei tot die krake van die vorm.

Om die doeltreffendheid en doeltreffendheid van die vorm te verseker, beveel ons aan dat u 'n paar dummy-siklusse uitvoer. Dit gee u die idee van die uitslag. Dit is belangrik om die inspeksie van seëls, gereelde instandhouding, veiligheidstelsels en deurbediening in u daaglikse inspeksieroetine op te neem. Hierdie instelling verskil egter van vervaardiger tot vervaardiger.

In case you are looking for more information on Kontak . Ons sal u alle inligting verskaf wat u benodig.