Vyapar Interview Questions and Answers

There are three types of gates on injection molds: sprue, runner, and gate.

• Sprue gate is the entry point for the molten plastic into the mold.

• Runner gate connects the sprue to the part cavity.

• Gate is the opening through which the plastic enters the part cavity.

• Types of gates include edge gate, submarine gate, tab gate, and more.

• The choice of gate type depends on the part design, material, and production requirements.

There are various types of molds used in tool rooms, including injection molds, blow molds, and compression molds.

• Injection molds are used to create plastic parts by injecting molten material into a mold cavity.

• Blow molds are used to create hollow plastic products, such as bottles, by blowing air into a molten plastic tube.

• Compression molds are used to shape materials, such as rubber, by applying pressure and heat.

• Other types of molds include transfer molds, rotational molds,...read more

Hot runner system is a heating system used in injection molding to keep the plastic material molten in the runner and nozzle.

• Hot runner system is used to reduce waste and improve cycle time in injection molding.

• It consists of a manifold, nozzles, and heaters that keep the plastic material molten.

• The system is controlled by a temperature controller that maintains the temperature of the plastic material.

• Hot runner systems can be either internally or externally heated.

• Examples o...read more

Plastic materials can be classified into thermoplastics, thermosets, and elastomers.

• Thermoplastics can be melted and re-molded, examples include polyethylene and PVC.

• Thermosets cannot be melted and re-molded, examples include epoxy and phenolic resins.

• Elastomers are rubber-like materials, examples include silicone and neoprene.

Sprue types are the channels through which molten metal is poured into a mold.

• Sprue can be open or closed

• Open sprue is used for top pouring and closed sprue is used for bottom pouring

• Sprue can be straight or tapered

• Tapered sprue helps in reducing turbulence and air entrapment

• Sprue can also be designed with a runner system to distribute the molten metal evenly