Lost foam process

The lost foam process uses a polystyrene foam having the same shape as

that of the object to be cast. In normal sand casting, molten aluminum is

poured into a cavity formed with bonded sand. In the lost foam process, the

foam pattern made of polystyrene is embedded into unbonded sand. During

pouring, the polystyrene foam pattern left in the sand is decomposed by

molten metal. The casting traces the polystyrene shape.

The foam pattern must be produced for every casting made. This process

starts with the pre-expansion of polystyrene beads, which contain pentane as a blowing agent. The pre-expanded beads are blown into a mold to form pattern sections. A steam cycle causes the beads to fully expand and fuse together in the mold. After cooling, the molded foam sections are assembled with glue, forming a cluster. The gating system (the passage liquid metal flows through) is also attached in a similar manner. Next the foam cluster is covered with a ceramic coating. The coating forms a barrier so that the molten metal does not penetrate or cause sand erosion during pouring. The coating also helps protect the structural integrity of the casting. After the coating dries, the cluster is placed into a flask and backed up with sand. Mold compaction is then achieved by using a vibration table to ensure uniform and proper compaction. Once this procedure is complete, the cluster is packed in the flask and the mold is ready to be poured. The molten metal replaces the foam, precisely duplicating all of the features of the pattern.

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Sudden movements may Destructive Machine

Vehicle engine maintenance rather than merely changing the oil, check the radiator, and submit it to the garage when damaged. Daily treatment given appropriate to the machine can be made ​​to avoid the various problems that should not happen, so the engine is not quickly broken. Some simple things you can do so is not easily damaged machine is as follows.

Before using the car, you must heat up the engine. Not just any heating, but heating is done properly. Let the machine you are working without a load for a while, so that lubricating oil can flow to every part of the machine that require. Accepted the burden of a sudden the engine would result in the engine lubricating oil to work before reaching any part of the machine that needs to be lubricated. When the surface of machine parts that rub against each other is allowed to work without a perfectly lubricated, the engine will be quickly worn.

Another thing to consider is the custom to put the foot on the clutch pedal. This habit will lead to pressure pads and clutch plates become damaged quickly. In addition, the clutch pedal is too often trampled upon at the time that is not necessary to make the clutch slip.

Avoiding sudden actions at the time of acceleration, deflection, and braking - except in emergencies - also helps the engine to keep it vibrant. When occasional, sudden action would result in the process of wear and tear takes place too quickly to engine parts, especially tires. Sudden action also makes machine loose connections. Moreover, when viewed in terms of safety, sudden action should not be done if not in an emergency. [Erf / arch]

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