Question & Answer

What are the functions of the screen pack and breaker plate at the die end of the extruder barrel?

The barrel and screw of an extruder are generally divided into three sections; identify the sections.

Briefly describe the plastic extrusion process.

Define die swell in extrusion

What does viscoelasticity mean, when applied to a polymer melt?

How does the viscosity of a polymer melt differ from most fluids that are Newtonian.

Viscosity is an important property of a polymer melt in plastics shaping processes. Upon what parameters does viscosity depend?

Identify the main categories of plastics shaping processes, as classified by the resulting product geometry.

What are some of the reasons why plastic shaping processes are important?

There are 10 correct answers in the following multiple choice questions (some questions have multiple answers that are correct). To attain a perfect score on the quiz, all correct answers must be given. Each correct answer is worth 1 point. Each omitted answer or wrong answer reduces the score by 1 point, and each additional answer beyond the correct number of answers reduces the score by 1 point. Percentage score on the quiz is based on the total number of correct answers.

12.1 Which one of the following terms refers to the glassy state of a material: (a) crystalline, (b) devitrified, (c) polycrystalline, (d) vitiated, or (e) vitreous?

12.2 Besides helping to preserve the environment, the use of recycled glass as an ingredient of the starting material in glassmaking serves what other useful purpose (one answer): (a) adds coloring variations to the glass for aesthetic value, (b) makes the glass easier to melt, (c) makes the glass stronger, or (d) reduces odors in the plant

12.3 The charge in glassworking is which one of the following: (a) the duration of the melting cycle, (b) the electric energy required to melt the glass, (c) the name given to the melting furnace, or (d) the starting materials in melting?

12.4 Typical glass melting temperatures are in which of the following ranges: (a) 400°C to 500°C, (b) 900°C to 1000°C, (c) 1500°C to 1600°C, or (d) 2000°C to 2200°C?

12.5 Casting is a glassworking process used for (a) high production, (b) low production, or (c) medium production?

12.6 Which one of the following processes or processing steps is not applicable in glassworking: (a) annealing, (b) pressing, (c) quenching, (d) sintering, and (e) spinning?

12.7 The press-and-blow process is best suited to the production of (narrow-necked) beverage bottles, while the blow-and-blow process is more appropriate for producing (wide-mouthed) jars: (a) true, or (b) false

12.8 Which one of the following processes is used to produce glass tubing: (a) Danner process, (b) pressing, (c) rolling, or (d) spinning?

12.9 If a glass part with a wall thickness of 5 mm (0.20 in) takes 10 minutes to anneal, how much time would a glass part of similar geometry but with a wall thickness of 7.5 mm (0.30 in) take to anneal (choose the one closest answer): (a) 10 minutes, (b) 15 minutes, (c) 20 minutes, or (c) 30 minutes?

12.10 A lehr is which of the following: (a) a lion's den, (b) a melting furnace, (c) a sintering furnace, (d) an annealing furnace, or (e) none of the above?

What are some of the design recommendations for glass parts?

Describe the type of material that is commonly used to make windshields for automobiles.

Describe how a piece of glass is heat treated to produce tempered glass.

What is the purpose of annealing in glassworking?

Two processes for forming glass fibers are discussed in the text. Name and briefly describe one of them

Describe the Danner process.

There are several ways of shaping plate or sheet glass. Name and briefly describe one of them

What is the main difference between the press-and-blow and the blow-and-blow shaping processes in glassworking?

Describe the spinning process in glassworking

Melting furnaces for glassworking can be divided into four types. Name three of the four types.

What are the three basic steps in the glassworking sequence?

What is the predominant chemical compound in almost all glass products?

Glass is classified as a ceramic material; yet glass is different from the traditional and new ceramics. What is the difference?

A large steel sand casting shows the characteristic signs of penetration defect: a surface consisting of a mixture of sand and metal. (a) What steps can be taken to correct the defect? (b) What other possible defects might result from taking each of these steps?

The housing for a certain machinery product is made of two components, both aluminum castings. The larger component has the shape of a dish sink, and the second component is a flat cover that is attached to the first component to create an enclosed space for the machinery parts. Sand casting is used to produce the two castings, both of which are plagued by defects in the form of misruns and cold shuts. The foreman complains that the parts are too thin, and that is the reason for the defects. However, it is known that the same components are cast successfully in other foundries. What other explanation can be given for the defects?