Part 3: Product, Process and Service Design Flashcards
Which of the following quality characteristics is an attribute?
A) Body temperature
B) Number of defects
C) Length of a bolt
D) Width of a board
B - Number of Defects
a defect is an attribute. Either defect is present or it is not. A defect has not real measurement on a continuous scale
A part will be inspected using a limit gage. An acceptable part is one that:
A) mates with both ends of the limit gage (both “go” and “no-go”)
B) mates only with the “no-go” end of the gage
C) mates with neither end of the limit gage
D) mates only with the “go” end of the limit gage
D - mates only with the “go” end of the limit gage
An acceptable part should only fit within the “go” end of the limit gage. If it passes on both ends, it is an unacceptable part.
A system has two components in parallel, each with a reliability of 0.95. The system reliability is approximately:
A) 0.9999
B) 0.9500
C) 0.9975
D) 0.0975
C - 0.9975
For components in parallel, each with reliability of p, the system reliability is given by
Rs(t) = 1 - (1 - 0.95)^2 = 0.9975
Consider the product/process development life cycle. The phase in which the product or process is released to the customer for use is referred to as the:
A) prototype phase
B) production phase
C) distribution phase
D) normal use phase
D - normal use phase
The normal use phase of the development life cycle includes release of the product/process to the customer for its intended use or function. Normal wear and maintenance occur in this phase as well.
Consider the following control frame. // (L) 0.01 A B C
0.01 represents the: A) primary datum B) geometric feature or characteristic C) geometric tolerance D) modifier
C - Geometric tolerance
Consider the following control frame. // (L) 0.01 A B C
“A” represents the:
A) Primary Datum
B) Secondary Datum
C) Tertiary Datum
D) modifier
A - Primary Datum
Which of the following involves demonstrating that all equipment being used in a process has been installed properly (as per manufacturer’s specifications)?
A) Installation qualification
B) Operational qualification
C) Performance qualification
D) Software qualification
A - Installation qualification
The goal is to make sure the equipment involved is installed properly.
Consider the product/process development life cycle. The phase in which all passible solutions are explored is referred to as the:
A) specification phase
B) prototype phase
C) concept phase
D) distribution phase
C - Concept phase
In the concept phase, all possible solutions are explored. Non-feasible solutions are eliminated.
A tool that is useful for converting customer needs into design concepts is:
A) process validation
B) quality function deployment
C) statistical process control
D) acceptance sampling
B - Quality function deployment (QFD)
QFD which uses the “house of quality” is helpful in turning customer needs into product characteristics or design concepts
Design reviews should be conducted by:
A) top management only
B) a quality engineer
C) a cross-functional team including quality, manufacturing, and suppliers, and so on
D) Customers only
C - a cross functional team including quality, manufacturing, suppliers, etc.
Because of the complexity of design review, a cross functional team consisting of many different personnel should conduct the review. The ream should include, but not be limited to, quality personnel, manufacturing, suppliers, customers, etc.
For each design review conducted, there are many different points of view from which the design should be considered. One of these viewpoints is from a reliability standpoint. Which of the following would be a question from a reliability view point?
A) Can the design be sufficiently tested?
B) Is the failure rate acceptably low?
C) Can the product be shipped without damage?
D) Can the parts needed for the design be obtained at an acceptable cost?
B - Is the failure rate acceptably low?
Reliability includes metrics such as failure rates for the design under consideration.
A specification is given as 8 (+.05/-.05). The limits for this specification are:
A) 8.00 and 8.05
B) 7.95 and 8.00
C) 7.95 and 8.05
D) 8. 5
C - 7.95 and 8.05
This bilateral tolerance with allowable variation in both directions.
For a process, confirming that specified requirements have been fulfilled is known as:
A) validation
B) verification
C) qualification
D) performance
B - Verification
Verification deals with determining whether the product or process satisfies specified requirements, that is, it meets all specifications or requirements. But this does not guarantee that the product or process specifications meet or exceed predetermined requirements (that is, it may not work like it is supposed to).
Validation of a product, process, or service is normally carried out:
A) during production or development
B) when customer requirements are determined
C) after completion of the product, process or service
D) None of the above
C - After completion of the product, process, or service
Validation is used to determine whether predetermined requirements are being met (product/process/service is working as intended)
The Design for X concept that focuses on eliminating problems before they occur is known as:
A) Design for reliability
B) Design for cost
C) Design for manufacturability
D) Design for six sigma
D - Design for six sigma
Design for Six Sigma is an approach used to eliminate problems before they occur
True/False. The reliability of a product can be measured at its release time.
False
Reliability can not be measured at the release time of the product; it can only be predicted. This is because the reliability of a product is dependent on many factors, including the system design, the reliability of its components, the operating environment, the environmental factor, san manufacturing defects.
The cumulative distribution function of failure at time t for a type of air conditioner is defined as F(t) = 4/5000. Which of the following statements is/are true
A) The probability that a randomly selected air conditioner fails by time t is 4/5000
B) The probability that a randomly selected air conditioner will instantly fail by time t is 4/5000
C) the fraction of all units in the lot of air conditioners that fail by time t is 4/5000
D) A and C
E) All of the above
D - A and C
The cumulative distribution function (cdf) of failure F(t) has two interpretations;
1) the probability that a randomly selected unit from the population will fail be time t
2) the fraction of all units in the population that fail by time t
The hazardous rate function h(t) defines the instantaneous failure rate at time t.
The cumulative distribution function of failure at time t for a computer model is 0.992. What fraction of this computer model fails by time t?
A) 0.992
B) 0.008
C) 1
D) None of the above
A - 0.992
The cumulative distribution function (cdf) of failure can be interpreted as the fraction of all units in the population that fail by time t. Since F(t) = 0.992 for this computer model, the fraction of this model that fail by time t is 0.992
Which of the following probability distributions is the only one to have a constant failure rate?
A) Uniform
B) Normal
C) Exponential
D) Weibull
C - Exponential
The exponential distribution is the only probability distribution to have a constant failure rate. For an exponential distribution with parameter λ, the hazard rate function h(t) = λ.
450 electrical components for a machine were subjected to a reliability test. The observed failures during 100-hour intervals are shown in the following table.
Upper bound (hrs) Number of failures, x 0 0 100 7 200 16 300 19 400 27
What is the estimated reliability at time t=200?
A) 0.0156
B) 0.9489
C) 0.0511
D) 0.0004
B - 0.9489
Upper bound (hrs) Number of failures, x Number of survivors
0 0 450
100 7 443
200 16 427
300 19 408
400 27 381
The estimated reliability at time t = 200 is
R(t)= n2/N= 427/450 = 0.9489
450 electrical components for a machine were subjected to a reliability test. The observed failures during 100-hour intervals are shown in the following table.
Upper bound (hrs) Number of failures, x 0 0 100 7 200 16 300 19 400 27
What is the estimated failure density for time 300 < t < 400?
A) 0.0006
B) 0.9067
C) 0.0933
D) 0.8467
A - 0.0006
Upper bound (hrs) Number of failures, x Number of survivors
0 0 450
100 7 443
200 16 427
300 19 408
400 27 381
The failure density is the probability density function defined as
f(t) = (n3-n4) / ((t3-t4) × N) = (408-381) / ((400-300) × 450) = 0.0006
450 electrical components for a machine were subjected to a reliability test. The observed failures during 100-hour intervals are shown in the following table.
Upper bound (hrs) Number of failures, x 0 0 100 7 200 16 300 19 400 27
What is the instantaneous rate of failure for time 300 < t < 400
A) 0.90667
B) 0.09333
C) 0.15333
D) 0.00066
D - 0.00066
Upper bound (hrs) Number of failures, x Number of survivors
0 0 450
100 7 443
200 16 427
300 19 408
400 27 381
The instantaneous rate of failure is the hazard rate function h(t) where:
h(t) = f(t) / h(t) = (n3-n4) / ((t3-t4) × n3) = (408 - 381) / ((400 - 300) × 408) = 0.00066
A series system is composed of 5 subsystems, each with reliability 0.995. What is the reliability of the system?
A) 0.9950
B) 0.9999
C) 0.9752
D) None of the above
C - 0.9752
A series system has n components connected end to end. If one component fails. The reliability of a series system made up of n components is:
Rs(t) = R1(t) × R2(t) × … ×Rn(t)
For this series system, the system reliability, therefore is:
Rs(t) = 0.995^5 = 0.9752
A parallel system is composed of 5 subsystems, each with reliability 0.995. The reliability of this system is closest to which of the following values?
A) 0.9950
B) 1.0000
C) .9752
D) None of the above
B - 1.0000
A parallel system is made up of components so that if one or more paths fail, the remaining path(s) are still able to perform properly. Therefore, the system fails when all units fail. The reliability of a parallels system is:
Rs(t) = 1 - F1(t) x F2(t) x … x Fn(t)
For this series system, the system reliability therefore is:
Rs(t) = 1 - ((1-0.995)^5) = 0.999999
The reliability of the system is essentially 1.
