Injection Molding Technologies — Summer 2021

Define Injection Molding. List any four products made by Injection Molding.

Explain the startup & shut down mechanism of Injection Molding process.

List the advantages& disadvantages of Injection Molding process.

What is pre drying of a material & why is it necessary? List the materials which need predrying.

Explain the single stage plunger machine with a figure.

What is a nozzle? List the types of nozzles used in Injection molding and explain any one.

Explain the open loop & closed loop microprocessor controlled injection molding system.

Define i) Injection shot capacity ii) L/Dratio iii) Maximum Day light.

Draw the screw used to process PVC & explain its importance.

Compare injection molding of thermoplastics with injection molding of thermosets.

What is back pressure? Explain briefly.

Explain the process of melting of a material in an injection screw in all the three zones.

Compare hydraulic & toggle clamping mechanisms.

Calculate the clamping force of a press with a hydraulic clamp having 600mm diameter clamping cylinder & hydraulic line pressure is 2000kg/cm2.

List the points of comparison between hydraulic and electric drive.

Explain the ring type non return valve with a neat sketch.

What is nitriding? Why is it necessary on screw and barrel?

With a neat graph explain the cycle time of injection molding process.

Draw a neat sketch of the standard screw and explain its terminologies.

What is MFI & how is it measured? Which range of MFI grade material is used for injection molding?

Briefly write the steps of a reciprocating screw type injection molding machine.

List any two causes and its remedies for the following defects in injection molded product i) Short shots ii) Bubbles & voids1

Discuss about the safety measures to be followed while operating an injection molding machine.

Draw PVT diagram & explain it briefly.

Explain the Gas assisted injection molding technique with a neat sketch.