MFE 2010 6, 8, 10 CPP Masehian

Casting, powder metallurgy, plastics

In the plaster-molding process, castings have a ................. surface finish with fine details.

good

Which of the following are advantages of sand casting over die casting (two best answers)?

higher melting temperature metals and larger parts

Which of the following metals would not typically be die cast?

tungsten

Misrun is a casting defect which occurs due to

Insufficient fluidity of the molten metal

Scabs are casting defects which:

Occur as rough and irregular projections on the surface of the casting

Which of the following casting processes is not a permanent mold operation?

Shell molding

Which of the following molds is more suited for the casting of high melting point metals?

Ceramic

Of the three polymers types, which is the most important commercially

thermoplastics

How is plastic sheet distinguished from plastic film?

Sheet is thicker than 0.5 mm, film is thinner

The function of the ejection system is to:

Separate the part from the cavity after molding

What are the main categories of plastics shaping processes classified by product geometry?

Continuous extruded products, molded parts, foamed products

Which of the following is NOT an extruded product shape?

Machined blocks

The parting line in injection molding is which one of the following?

where the two mold halves come together

Use of a parison is associated with which one of the following plastic shaping processes:

blow molding

Powder metallurgy is most economic for:

 

Large batch size

Which of the following statement(s) is(are) correct?

Both of the above

What is the purpose of impregnation in powder metallurgy (two best answers)?

putting polymers into the pores of a PM part and soaking oil by capillary action into the pores of a PM part

Which of the following most closely typifies the sintering temperatures in PM?

0.8 of melting point

Which of the following design features would be difficult or impossible to achieve by conventional pressing and sintering (three best answers)?

side holes, threaded holes, outside rounded corners