Question & Answer

A product whose total work content time = 50 minutes is to be assembled on a manual production

line. The required production rate is 30 units per hour. From previous experience with similar

products, it is estimated that the manning level will be close to 1.5. Assume that the uptime

proportion and line balancing efficiency are both = 1.0. If 9 seconds will be lost from the cycle time

for repositioning, determine (a) the cycle time and (b) the numbers of workers and stations that will

be needed on the line.

A final assembly plant for a certain automobile model is to have a capacity of 240,000 units

annually. The plant will operate 50 weeks/yr, 2 shifts/day, 5 days/week, and 8.0 hours/shift. It will

be divided into three departments: (1) body shop, (2) paint shop, (3) trim-chassis-final department.

The body shop welds the car bodies using robots, and the paint shop coats the bodies. Both of these

departments are highly automated. Trim-chassis-final has no automation. There are 15.5 hours of

direct labor content on each car in this department, where cars are moved by a continuous conveyor.

Determine (a) hourly production rate of the plant, (b) number of workers and workstations required

in trim-chassis-final if no automated stations are used, the average manning level is 2.5, balancing

efficiency = 93%, proportion uptime = 95%, and a repositioning time of 0.15 min is allowed for

each worker.

A single model manual assembly line produces a product whose work content time = 47.8 min. The

line has 24 workstations with a manning level = 1.25. Available shift time per day = 8 hr, but

downtime during the shift reduces actual production time to 7.6 hr on average. This results in an

average daily production of 256 units/day. Repositioning time per worker is 8% of cycle time.

Determine (a) line efficiency, (b) balancing efficiency, and (c) repositioning time.

A manual assembly line produces a small appliance whose work content time = 25.9 min. Desired

production rate = 50 units/hr. Repositioning time = 6 sec, line efficiency = 95%, and balancing

efficiency is 93%. How many workers are on the line?

A manual assembly line is being designed for a product with annual demand = 100,000 units. The

line will operate 50 wks/year, 5 shifts/wk, and 7.5 hr/shift. Work units will be attached to a

continuously moving conveyor. Work content time = 42.0 min. Assume line efficiency = 0.97,

balancing efficiency = 0.92, and repositioning time = 6 sec. Determine (a) hourly production rate to

meet demand, (b) number of workers required, and (c) the number of workstations required if the

estimated manning level is 1.4.

There are 21 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

on the quiz is based on the total number of correct answers.

39.1 Material handling is usually not associated with transportation between facilities that involves rail,

truck, air, or waterway delivery of goods: (a) true or (b) false?

39.2 Fixed routing is associated with which of the following types of manufacturing systems (two best

answers): (a) automated production lines, (b) automated storage systems, (c) cellular manufacturing

systems, (d) flexible manufacturing systems, (e) job shops, and (f) manual assembly lines?

39.3 Which of the following types of material handling equipment are typically used in a process type

layout (two best answers): (a) conveyors, (b) cranes and hoists, (c) fork lift trucks, and (d) railguided

vehicles?

39.4 Batch model production lines are most suited to which one of the following production situations:

(a) job shop, (b) mass production, or (c) medium production?

39.5 Precedence constraints are best described by which one of the following: (a) launching sequence in

a mixed model line, (b) limiting value of the sum of element times that can be assigned to a worker

or station, (c) order of workstations along the line, or (d) sequence in which the work elements must

be done?

39.6 Which of the following phrases are most appropriate to describe the characteristics of tasks that are

performed at automated workstations (three best answers): (a) complex, (b) consists of multiplework elements, (c) involves a single work element, (d) involves straight-line motions, (e) requires

sensory capability, and (f) simple?

39.7 The transfer line is most closely associated with which one of the following types of production

operations: (a) assembly, (b) automotive chassis fabrication, (c) machining, (d) pressworking, or (e)

spot welding?

39.8 A dial indexing machine uses which one of the following types of workpart transfer: (a)

asynchronous, (b) continuous, (c) parts passed by hand, or (d) synchronous?

39.8 A dial indexing machine uses which one of the following types of workpart transfer: (a)

asynchronous, (b) continuous, (c) parts passed by hand, or (d) synchronous?

39.10 Most parts classification and coding systems are based on which of the following types of part

attributes (two best answers): (a) annual production rate, (b) date of design, (c) design, (d)

manufacturing, and (e) weight?

39.11 What is the dividing line between a manufacturing cell and a flexible manufacturing system: (a) two

machines, (b) four machines, or (c) six machines?

39.12 A machine capable of producing different part styles in a batch mode of operation qualifies as a

flexible manufacturing system: (a) true or (b) false?

39.13 The physical layout of a flexible manufacturing system is determined principally by which one of

the following: (a) computer system, (b) material handling system, (c) part family, (d) processing

equipment, or (e) weight of parts processed?

39.14 Industrial robots can, in general, most easily handle which one of the following part types in a

flexible machining system: (a) heavy parts, (b) metal parts, (c) nonrotational parts, (d) plastic parts,

or (e) rotational parts?

39.15 Flexible manufacturing systems and cells are generally applied in which one of the following areas:

(a) high-variety, low-volume production, (b) low variety, (c) low volume, (d) mass production, (e)

medium-volume, medium-variety production?

39.16 Which one of the following technologies is most closely associated with flexible machining

systems: (a) lasers, (b) machine vision, (c) manual assembly lines, (d) numerical control, or (f)

transfer lines?

Define computer integrated manufacturing.

What are the advantages of FMS technology, compared to conventional batch operations?

Name some of the FMS software and control functions

What are the criteria that should be satisfied to make an automated manufacturing system flexible?

What is a flexible manufacturing system?

What is the composite part concept in group technology?

Define cellular manufacturing.

What is a part family?

Define group technology.

What are some of the reasons for downtime on a machining transfer line?

Why are single station assembly cells generally not suited to high-production jobs?

Repositioning time on a synchronous transfer line is known by a different name; what is that name?

Why must a production line be paced at a rate higher than that required to satisfy the demand for the

product?

Why are parts sometimes fixed to the conveyor in a continuous transfer system in manual

assembly?

Briefly define the three types of mechanized workpart transfer systems used in production lines.

Describe how manual methods are used to move parts between workstations on a production line.

What are some of the limitations of a mixed model line compared to a batch model line?

What are the advantages of a mixed model line over a batch model line for producing different

product styles?

What is a production line?