GATE Overflow for GATE XE - Recent activity in Polymer Processing

Edited: GATE XE 2026 | Question: 121

Thu, 02 Apr 2026 08:45:30 +0000

A single-screw extruder is operated at $12$ $\mathrm{rpm}$ under open discharge condition (i.e., without a die).

The screw has a diameter of $10$ $\mathrm{cm}$, a distance of $2.5$ $\mathrm{cm}$ between the adjacent flights, a gap of $0.25$ $\mathrm{cm}$ between the screw and the inner wall of the barrel, and a helix angle (i.e., angle between the flights and the plane perpendicular to the screw axis) of $8^{\circ}$.

If the flow of the molten polymer in the metering zone through the extruder is assumed isothermal, Newtonian and incompressible, the volumetric flow rate of the polymer melt is $\_\_\_\_\_\_$ $\mathrm{cm}^{3} / \mathrm{min}$ (rounded off to the nearest integer).

Edited: GATE XE 2026 | Question: 105

Thu, 02 Apr 2026 07:46:27 +0000

Select the correct option to match the Product with the most appropriate Processing technique from the table given below:

Product		Processing technique
$\text{P}$	Fibre-reinforced pressure vessel	$1$	Rotomoulding
$\text{Q}$	Overhead water tank	$2$	Thermoforming
$\text{R}$	Blister package for medicine	$3$	Filament winding
$\text{S}$	Plastic carry bag	$4$	Blown film extrusion

$\text{P-III ; Q-II ; R-I ; S-IV}$
$\text{P-IV ; Q-III ; R-II ; S-I}$
$\text{P-II ; Q-I ; R-III ; S-IV}$
$\text{P-III ; Q-I ; R-II ; S-IV}$

Edited: GATE XE 2026 | Question: 36

Tue, 31 Mar 2026 08:03:22 +0000

Which one of the following polymer processing techniques involves shaping a heated sheet?

Thermoforming
Injection molding
Blow molding
Extrusion

Edited: GATE XE 2025 | Question: 121

Mon, 30 Jun 2025 15:31:57 +0000

Choose the option(s) that correctly match(es) the $\textbf{Zones}$ with their typical $\textbf{Functions}$ in an industrial extruder

$$\begin{array}{|l|l|l|l|} \hline & \textbf{Zones} && \textbf{Functions} \\ \hline P & \text{Feed zone} & 1 & \text{The melt acquires a constant flow rate} \\ \hline Q & \text{Compression zone} & 2 & \text{No heating takes place} \\ \hline R & \text{Metering zone} & 3 & \text{Polymer melts due to heat transferred} \\ &&& \text{from the heating element} \\ \hline & & 4 & \text{The helical flight of the screw imparts} \\ &&& \text{constant flow of the melt} \\ \hline & & 5 & \text{Polymer melts due to shear forces} \\ &&& \text{imparted by the screw} \\ \hline \end{array}$$

$\text{P-2; Q-5; R-1}$
$\text{P-2; Q-3; R-4}$
$\text{P-5; Q-1; R-2}$
$\text{P-2; Q-1; R-3}$

Edited: GATE XE 2025 | Question: 119

Mon, 30 Jun 2025 15:28:36 +0000

Injection molding is typically used to make plastic parts. If the pressure at the gate is monitored as a function of time during the injection of a thermoplastic polymer, identify the profile that best describes this event.

$\text{Q}$
$\text{R}$
$\text{P}$
$\text{S}$

Edited: GATE XE 2025 | Question: 115

Mon, 30 Jun 2025 15:10:40 +0000

Match the Product with the most appropriate Processing Technique employed.

$$\begin{array}{|l|l|l|l|} \hline & \textbf{Product} & & \textbf{Processing Technique} \\ \hline P & \text{Rainboots} & 1 & \text{Blow molding} \\ \hline Q & \text{Disposable plastic cups} & 2 & \text{Calendering} \\ \hline R & \text{Soft drink bottles} & 3 & \text{Rotational molding} \\
\hline S & \text{Flexible films} & 4 & \text{Thermoforming} \\ \hline \end{array}$$

$\mathrm{P}-3 ; \mathrm{Q}-1 ; \mathrm{R}-2 ; \mathrm{S}-4$
$\mathrm{P}-3 ; \mathrm{Q}-4 ; \mathrm{R}-1 ; \mathrm{S}-2$
$\mathrm{P}-1 ; \mathrm{Q}-2 ; \mathrm{R}-4 ; \mathrm{S}-3$
$\mathrm{P}-1 ; \mathrm{Q}-3 ; \mathrm{R}-4 ; \mathrm{S}-2$

Recategorized: GATE XE 2023 | Question: 104

Mon, 05 May 2025 12:17:00 +0000

\begin{tabular}{|c|c|c|c|c|}
\hline \multirow[t]{3}{*}{ Q. 114} & \multicolumn{4}{|c|}{\begin{tabular}{l}
A high molecular weight polymer passes through different zones from the hopper \\
to the die in an extruder. Among the options given, identify the correct match \\
between the zones and their key functions.
\end{tabular}} \\
\hline & \multicolumn{2}{|c|}{ Zones } & \multicolumn{2}{|c|}{ Key functions } \\
\hline & P & Metering zone & 1 & \begin{tabular}{l}
High shear forces for effective \\
mixing
\end{tabular} \\
\hline & Q & Compression zone & 2 & Receives the charge or feed \\
\hline & R & Feed zone & 3 & \begin{tabular}{l}
Melts the charge or feed through \\
heat conducted by the heating \\
element
\end{tabular} \\
\hline & S & Working zone & 4 & \begin{tabular}{l}
The charge or feed acquires a \\
constant flow rate imparted by the \\
helical flight of the screw
\end{tabular} \\
\hline

& P-4; & $-3 ; R-2 ; S-1$ & & \\
\hline
& P-3; & $-4 ; \mathrm{R}-1 ; \mathrm{S}-2$ & & \\
\hline
& P-4; & $-1 ; \mathrm{R}-2 ; \mathrm{S}-3$ & & \\
\hline
& P-3; & ; R-2; S-4 & & \\
\hline
\end{tabular}

Recategorized: GATE XE 2023 | Question: 109

Mon, 05 May 2025 12:16:41 +0000

\begin{tabular}{|c|c|c|c|c|}
\hline \multirow[t]{6}{*}{ Q. 119} & \multicolumn{4}{|c|}{\begin{tabular}{l}
From the options given, identify the correct match(es) between the polymer \\
products with the most appropriate processing technique.
\end{tabular}} \\
\hline & \multicolumn{2}{|c|}{ Polymer product } & \multicolumn{2}{|c|}{ Processing technique } \\
\hline & $\mathrm{P}$ & Fishing rods & 1 & Compression moulding \\
\hline & Q & Soft drink bottles & 2 & Thermoforming \\
\hline & $\mathrm{R}$ & Plastic sheets & 3 & Pultrusion \\
\hline & S & Plastic trays & 4 & Blow moulding \\
\hline

& \multicolumn{4}{|c|}{ P-3; Q-4; R-1; S-2 } \\
\hline
& \multicolumn{4}{|c|}{ P-3; Q-2; R-1; S-4 } \\
\hline
& \multicolumn{4}{|c|}{ P-1; Q-2; R-3; S-4 } \\
\hline
& \multicolumn{4}{|c|}{ P-3; Q-4; R-1; S-1 } \\
\hline
\end{tabular}

Recategorized: GATE XE 2023 | Question: 118

Mon, 05 May 2025 12:16:13 +0000

Q. 128 A polymeric material of density $0.9 \mathrm{~g} / \mathrm{cc}$ and melt volume of $10 \mathrm{cc}$ in an extruder has a residence time of $100 \mathrm{~s}$. The output of the extruder is $\mathrm{kg} / \mathrm{h}$. (Rounded off to two decimal places)

Recategorized: GATE XE 2024 | Question: 106

Mon, 05 May 2025 10:54:34 +0000

Thermoforming operation of semi-crystalline polymers with glass transition temperature, $T_{g}$, and melting temperature, $T_{m}$, is carried out at a temperature $T$, in the range of

$T_{g} < T < T_{m}$
$T_{g} < T < T_{m}$
$T_{g}>T=T_{m}$
$T_{g}>T>T_{m}$