Which joining method involves melting the base metals together?

• Riveting

• Soldering

• Welding

• Brazing

Answer explanation

Welding is the joining method that involves melting the base metals together, allowing them to fuse as they cool. In contrast, riveting, soldering, and brazing do not involve melting the base metals.

What is a key difference between injection molding and compression molding regarding the materials they typically process?

• Injection molding processes thermosets, while compression molding processes thermoplastics.

• Injection molding processes metals, while compression molding processes plastics.

• Injection molding processes thermoplastics, while compression molding processes thermosets.

• Injection molding processes ceramics, while compression molding processes metals.

Answer explanation

The correct choice highlights that injection molding typically processes thermoplastics, which can be melted and reshaped, while compression molding is used for thermosets, which harden permanently after being shaped.

Why is injection molding most commonly used for large-scale plastic part production?

• It has low tooling costs

• It works well with thermosetting polymers

• It is fast and highly automated

• It creates stronger parts than metal forming

Answer explanation

Injection molding is preferred for large-scale production because it is fast and highly automated, allowing for efficient manufacturing of large quantities of plastic parts with consistent quality.

Which manufacturing process involves plastically deforming metal using a hammer and closed dies?

• Forging

• Rolling
  

• Die casting

• Turning

Answer explanation

Forging is the manufacturing process that involves plastically deforming metal using a hammer and closed dies, shaping the metal into desired forms through compressive forces.

Which of the following manufacturing processes would be most appropriate for producing a long aluminum window frame with a constant cross-section?

• Sand casting

• Extrusion

• Injection molding

• Rolling

Answer explanation

Extrusion is ideal for producing long shapes with a constant cross-section, like aluminum window frames. It allows for continuous production and efficient shaping, unlike sand casting or injection molding, which are not suited for this application.

What is a primary disadvantage of sand casting compared to other casting processes?

• It can only be used for a limited range of metals.

• It has very high initial costs.

• It produces parts with a poor surface finish.

• It cannot produce large or complex parts.

Answer explanation

A primary disadvantage of sand casting is that it produces parts with a poor surface finish compared to other casting methods, which can require additional machining or finishing processes.

Which of the following best describes a disadvantage of sand casting?

• Only suitable for non-ferrous metals
  

• Limited to small parts only
  

• Produces poor surface finish and low accuracy

• Requires extremely high pressure to form

Answer explanation

The correct choice highlights a key disadvantage of sand casting: it often results in a poor surface finish and low dimensional accuracy, making it less suitable for applications requiring high precision.

Which of the following is a machining process used to create a cylindrical shape by removing material from a rotating workpiece?

• Drilling

• Turning

• Forging

• Extrusion

Answer explanation

Turning is a machining process that involves removing material from a rotating workpiece to create cylindrical shapes. Drilling, forging, and extrusion do not specifically focus on creating cylindrical forms through this method.

Which casting process is generally more suitable for large production runs of non-ferrous metals due to its ability to achieve tight tolerances and excellent surface finish, despite high startup costs?

• Sand casting

• Investment casting

• Die casting

• Lost-foam casting

Answer explanation

Die casting is ideal for large production runs of non-ferrous metals because it provides tight tolerances and excellent surface finishes, making it more efficient despite higher initial costs compared to other methods.

Hot rolling requires more force to plastically deform steel than cold rolling

• True

• False

Answer explanation

Cold rolling requires more force to plastically deform steel than hot rolling because the steel is stronger at lower temperatures. Therefore, the statement is false.