quiz 1 hot runner

 _____________ HR nozzles- leaving a short point sprue

• Open nozzles

• nozzles with tip

• nozzles to side gating

•  both (a) & (b)

A HR system consists of the following functional zones:

• sprue bushing & distributor

• nozzle & gate

• none of them

• both (a) & (b)

HR systems have the following requirements

• leakproofness of system

• maintaining a flow balance

• ease of cleaning and replacement of worn components

• All of the above

Hot runner systems are ______________ for injection molds which convey molten plastic from the machine nozzle into the cavity

• feed systems

• ejection system

• injection system

• all of the above

In a typical 16-cavity mould the quantity of waste for three types of gating can be compared and identify the mould with zero wastage.

Fig (a)  with cold runners throughout

 

Fig (b) mould with a simple HR system with four nozzles

 

Fig (c) mould with a full HR system

• Fig (a)

• Fig (b)

• Fig (c)

• Fig (b) Fig (c)

 ___________________closer of the gate takes place with the aid of a movable pin which is introduced into the gate aperture.

• Manual

• Electrical

• Mechanical

• Electro-mechanical

Type of nozzles used to locate the gate on the side wall of the product

• open nozzles

• shut off nozzles

• Tip Nozzles

• Edge nozzles

________________ nozzle  is the only nozzle that allow HR to be used for injection molding of structural foam and cascade molding.

• open nozzles

• Edge nozzles

• Shut off nozzle

• Tip Nozzles

Too low temperature in the front section of nozzle causes blocking of gate and if temperature is too high then uncontrolled _______________ defect will arise which is difficult to eliminate.

• drooling

• clogged nozzle

• both a and b

• none of them

The gate size and configuration are based on

• melt flow

• size of product

• aesthetic requirement

• all of the above