This set of Casting, Forming and Welding Multiple Choice Questions & Answers (MCQs) focuses on “Methods of Ramming Mold Boxes – 1”.
1. What is the disadvantage of hand molding?
a) Damage to the projections
b) Costly method
c) Non-uniform strength
d) Poor surface finish of the mold
View Answer
Explanation: In hand molding, the ramming force required for compressing the molding sand is applied by human hand. A human knows about projection in the pattern accordingly he applies force thus no damage to projections. Surface finish obtained is also good. But, the force applied is non-uniform which results in non-uniform strength.
2. Which is not a machine molding process?
a) Jolting
b) Squeezing
c) Sand slinging
d) Hand molding
View Answer
Explanation: In jolting, a sand-filled mold is raised to a certain height and allowed to fall freely onto the ground converting potential energy into impact energy which leads to ramming of sand. In squeezing, a press is used to apply pressure through a plate. In the sand slinging, small-small amount of sand will be thrown that leads to localized ramming of sand. Hand molding is done without machines.
3. Which machine molding process will give uniform strength throughout the mold?
a) Sand slinging
b) Squeezing
c) Jolt and squeezing
d) Jolting
View Answer
Explanation: In sand slinging, we will obtain uniform strength throughout the mold because localized ramming of sand takes place because of throwing the small-small amount of sand into the mold box at the same amount of force. But in other processes strength will be more at the top or bottom or middle.
4. In which of the following molding process strength at the top of the mold is higher?
a) Hand molding
b) Squeezing
c) Jolting
d) Jolt and Squeezing
View Answer
Explanation: In squeezing, we apply force with the help of a ram. Due to applied pressure ramming of sand takes place but the same load is not able to transmit to the bottom of the mold resulting in lower strength at the bottom portion of the mold. But, in jolting impact force act at the bottom. In jolt and squeezing, uniform strength will be achieved. In hand molding, strength will be non-uniform.
5. In which of the following molding process strength at top of the mold is less?
a) Hand molding
b) Squeezing
c) Jolting
d) Jolt and Squeezing
View Answer
Explanation: During jolting, the sand-filled mold is taken to a certain height so that it possesses potential energy and then allowed to fall freely onto the ground. Due to impact force transmitted to the bottom of the mold is very high when compared to the top of the mold that leads to high strength at the bottom and low strength at top of the mold.
6. Which of the following molding methods is the most costly?
a) Sand slinging
b) Jolt and squeezing
c) Jolting
d) Hand molding
View Answer
Explanation: Sand slinging machine is costly, also involves more cycle time and thus results in higher power consumption. Thus the cost involved is more. In jolting and jolt with squeezing machine cost is less with less cycle time, and in hand molding, no machine is used thus less costly than sand slinging.
7. Which of the following molding methods have the least production rate?
a) Squeezing
b) Jolt and squeezing
c) Jolting
d) Hand molding
View Answer
Explanation: In hand molding operation the force required for ramming the mold is applied by human hand thus the time taken for making the mold is longer. This leads to the least production rate when compared with the above processes. Whereas in other methods machines are used reducing the production time.
8. Which of the following molding methods have the highest production rate?
a) Squeezing
b) Jolt and squeezing
c) Jolting
d) Sand slinging
View Answer
Explanation: In jolting, we only need to take the mold to a certain height and then drop it. Thus highest production rate of the is achieved. Sand slinging requires more time as it is a repetitive process. Jolt and squeezing combines both jolting and squeezing hence will take more time than jolting. In squeezing, we need to keep the force for a certain time which reduces the production rate.
9. Jolt and squeezing can be used for achieving uniform strength if the height of the mold is up to 200 mm.
a) True
b) False
View Answer
Explanation: Jolt and squeezing is a combination of jolting and squeezing. First of all jolting is done followed by squeezing. If the height of mold is less than 200 mm, throughout the depth of mold uniform strength is achieved. If the height of mold is more than 200 mm, the force will not transmit to the middle portion of mold hence, less strength at center.
10. In the sand slinging process we can’t use a pattern with extension or projection.
a) True
b) False
View Answer
Explanation: During sand slinging, sand is thrown with a higher amount of force into the mold box and will hit the projection present on the pattern. This will result in the damage of the pattern. Thus, the sand slinging operation is used only for a simple pattern without any projection or extension.
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