1.
Which of the following material is not made by injection molding?
Correct Answer
B. Tubes
Explanation
Injection molding is a manufacturing process in which molten material is injected into a mold to form a desired shape. Nuts, car handles, and electrical fittings can all be made using injection molding as they are solid objects. However, tubes are typically made using extrusion, where a material is forced through a die to form a continuous shape. Therefore, tubes are not made by injection molding.
2.
What is the minimum temperature allowed to be given to the injection molding process?
Correct Answer
D. 150°C
3.
What is the maximum temperature allowed to be given to the injection molding process?
Correct Answer
A. 300°C
Explanation
The maximum temperature allowed to be given to the injection molding process is 300°C. This temperature limit ensures that the material being injected does not degrade or burn during the molding process. Higher temperatures can cause the material to lose its properties and result in poor quality finished products. Therefore, it is important to adhere to the specified temperature limit to ensure the integrity and quality of the molded products.
4.
In blow molding, to inflate soft plastic, which medium is used?
Correct Answer
A. Air
Explanation
In blow molding, air is used to inflate soft plastic. This is because air is readily available, cost-effective, and easy to control. It allows for the expansion and shaping of the plastic material into the desired form. Using water, oil, or alcohol as a medium for inflation would not be suitable as they may not provide the necessary pressure or control required for the blow molding process.
5.
Which of the following plastics is not used in blow molding?
Correct Answer
A. Terephthalate
Explanation
Terephthalate is not used in blow molding because it has a high melting point and is not easily malleable. Blow molding requires a plastic that can be melted and shaped into a hollow form, which is not possible with terephthalate. Polypropylene, polythene, and PVC are commonly used in blow molding due to their lower melting points and ability to be easily molded into various shapes.
6.
What is the minimum air pressure required in the blow molding process?
Correct Answer
B. 400 kPa
Explanation
In the blow molding process, the minimum air pressure required is 400 kPa. This pressure is necessary to ensure that the plastic material is properly inflated and takes the shape of the mold. If the pressure is too low, the plastic may not fully expand, leading to defects in the final product. On the other hand, if the pressure is too high, it can cause the plastic to rupture or deform. Therefore, 400 kPa is the optimal air pressure for the blow molding process.
7.
Which of the following is not a type of the blow molding process?
Correct Answer
C. Multi-smaller blow molding
Explanation
Multi-smaller blow molding is not a type of the blow molding process. This can be inferred from the fact that the other options, injection blow molding, extrusion blow molding, and multi-larger blow molding, are all recognized processes in blow molding. The term "multi-smaller" does not align with any commonly known blow molding technique, suggesting that it is not a valid option in this context.
8.
Which of the following is not an application of the blow molding process?
Correct Answer
B. Door liners
Explanation
The blow molding process is commonly used to manufacture hollow plastic products by inflating a heated plastic tube into the desired shape. Toy bodies, bottles, and pipes are all examples of products that can be made using blow molding. However, door liners are not typically produced using this process. Door liners are usually made from materials such as wood, metal, or plastic sheets that are cut and shaped to fit the interior of a door frame, rather than being formed through blow molding.
9.
Which of the following molding processes is widely used for the manufacturing of plastic bottles?
Correct Answer
D. Blow molding
Explanation
Blow molding is widely used for the manufacturing of plastic bottles. This process involves melting plastic and then blowing air into a mold to create the desired shape. It is a cost-effective and efficient method for producing large quantities of plastic bottles with consistent quality and high production rates. Blow molding allows for the production of bottles with various shapes, sizes, and thicknesses, making it the preferred choice for the plastic bottle manufacturing industry.
10.
Which of the following materials is mostly used for making thermoforming molds?
Correct Answer
C. Aluminum
Explanation
Aluminum is mostly used for making thermoforming molds because it has several advantageous properties. It is lightweight, which makes it easier to handle and reduces the weight of the mold itself. Aluminum also has excellent thermal conductivity, allowing for efficient heat transfer during the thermoforming process. Additionally, aluminum is highly corrosion-resistant, ensuring the longevity of the molds. Its malleability and ease of machining make it a cost-effective choice for creating complex mold designs.
11.
Blow molding is a very slow process. However economical to produce products of better quality.
Correct Answer
B. False
Explanation
Blow molding is a manufacturing process used to create hollow plastic objects. It is actually a fast process, not a slow one. While it is economical, it does not necessarily guarantee better quality products. Therefore, the statement is false.
12.
In the extrusion blow molding process, it is very difficult to trim away excess plastics.
Correct Answer
A. True
Explanation
In the extrusion blow molding process, excess plastics are difficult to trim away. This is because the excess plastics are formed as a result of the extrusion process, where molten plastic is forced through a die to create the desired shape. Trimming away these excess plastics can be challenging due to their location and the complexity of the shape being formed. Therefore, it is true that it is very difficult to trim away excess plastics in the extrusion blow molding process.
13.
Single stage stretch blow molding process is mostly used for small-level production.
Correct Answer
A. True
Explanation
The single stage stretch blow molding process is mainly utilized for small-scale production due to its efficiency and cost-effectiveness. This process involves the production of both the preform and the final product in a single machine, eliminating the need for multiple steps and reducing production time. It is ideal for smaller production runs where speed and flexibility are essential, making it a suitable choice for small-level production.
14.
Melting section is another name for which section?
Correct Answer
B. Transition section
Explanation
The melting section is another name for the transition section. This section is responsible for melting the solid material and converting it into a molten state. It is typically located between the feed section and the pumping section in a process or system.
15.
How are extruded materials cooled?
Correct Answer
D. Oil
Explanation
Extruded materials are cooled by using oil. This is because oil has a higher heat capacity and thermal conductivity compared to water, air, or contact with a chilled surface. The high heat capacity of oil allows it to absorb more heat from the extruded material, effectively cooling it down. Additionally, oil provides a more uniform cooling process, ensuring that the entire surface of the extruded material is cooled evenly.
16.
Which of the following is not an important factor of cooling in extrusion?
Correct Answer
C. Ease of adding colors
Explanation
The ease of adding colors is not an important factor in cooling during extrusion. Cooling in extrusion is primarily important for reducing shrinkage and distortion in the material. The rate of cooling is also crucial to ensure proper solidification and dimensional stability of the extruded product. However, the ease of adding colors does not directly affect the cooling process and its importance lies more in the aesthetic aspect of the final product rather than the cooling process itself.
17.
Which of the following is not an application of polymer extrusion?
Correct Answer
D. Circuit boards
Explanation
Polymer extrusion is a process used to create continuous shapes by forcing molten polymer through a die. It is commonly used in various applications such as door insulation seals, cables, and circuit boards. However, circuit boards are typically manufactured using printed circuit board (PCB) fabrication methods, which involve etching copper layers onto a substrate rather than extruding polymers. Therefore, circuit boards are not an application of polymer extrusion.
18.
Which of the following equipment is used for controlling the temperature of polymer material in the extrusion process?
Correct Answer
C. Thermocouple
Explanation
A thermocouple is a device used for measuring temperature in various industrial processes, including extrusion. It consists of two different metals joined together, which produce a voltage that is proportional to the temperature difference between the two junctions. This voltage is then used to determine the temperature of the polymer material during extrusion. Therefore, a thermocouple is the appropriate equipment for controlling the temperature of polymer material in the extrusion process.
19.
Tubes having a U shape cannot be manufactured by the polymer extrusion process.
Correct Answer
B. False
Explanation
Tubes having a U shape can be manufactured by the polymer extrusion process. The polymer extrusion process involves pushing molten polymer through a die to create a continuous shape. This process can be used to create tubes with various shapes, including U shapes. Therefore, the statement is false.
20.
In compression molding, the curing time does not depend on which of the following factors?
Correct Answer
B. Curing temperature
Explanation
In compression molding, the curing time is not dependent on the curing temperature. This means that regardless of the temperature at which the material is cured, the time it takes for the material to fully cure will remain the same. The curing time is more likely to be influenced by factors such as the material being used, the geometry of the mold, and the thickness of the material being molded.