Tqm Case Decfab Inc.

8/2/2019 Tqm Case Decfab Inc.

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1. Develop a Pareto diagram for the Problem solving team that describes the major

causes of the problems with the production process of the dental drill.

The Pareto Diagram is effective to understand the major causes of problem and

their occurrence frequency. In the above Diagram it is identified that the major

problem on the production line is Poor Machining and its frequency is 58 out of

110 which 53%. The Decfab has the opportunity to improve its quality by solving

poor machining problem.



2. Develop a histogram for the team of the diameter frequency data for the dental

drill production process.

The Histogram is effective to understand the major causes of problem and their

occurrence frequency. In the above Diagram it is identified that the major problem

on the production line is Poor Machining and its frequency is 58 and second

major cause of problem is Bad Incoming Part.



3. Develop a P-chart using three standard deviations to help Mr. Hanson determine

if the quality of incoming parts from the Ajax Company are poor or not.

The quality of incoming parts from the Ajax Company are poor because out of 12

samples 1 sample is out of the UCL also the variation among the UCL and LCL is

very high due to high variation in the poor quality parts imported from Ajax

Company.



4. What does the P-chart tell you about the incoming parts from the Ajax

Company?

P Chart tells that incoming parts from Ajax company has very poor quality, out of

12 samples, observation 7 has 24 poor quality part from 2500 parts so observation

7 is outlier and it fall outside the control limits. In this instance, the process is out

of control.

The continuous change in the poor quality parts with high density indicates that the

production line of Ajax Company is not following good quality control over the

Production.



5. Develop X-bar and R charts for the screw data from the Delta Machining

Company, using historical process information to determine the center lines.

The above chart shows that out of the sample data given about the screw from the

delta company none of the points fall outside the control limits UCL or LCL, so on

the basis of the observations taken it can be said that the process is in control and

there are no rejections.

X Double Bar = ∑ X BAR/ n = 0.54



The above chart shows that out of the sample data given about the screw from the

delta company none of the points fall outside the control limits UCL or LCL, so on

the basis of the samples it can be said that the process is in control and there are no

rejections.

R BAR = ∑ R/ n = 0.211



6. Does DecFab have a problem with the screw part from the Delta Machining

Company? If so, why? If not, why not?

No, The screw parts from the Delta Machining Company do not have any major problem can be said on the basis of the X BAR Chart where the samples are in

between the UCL and LCL also the variation of screw diameters is very low.

The screw parts from the Delta Machining Company do not have any major

problem can be said on the basis of the R BAR Chart where the samples are in

between the UCL and LCL but the variation of screw diameters is little high which

can be reduce for better quality Product.



7. What is the failure rate for the dental drill, based on the reliability testing?

Failure rate = Number of failures

Number of units tested

Here, number of failures = 3 and number tested = 6

So, Failure rate = 3/6

= 0.5 or 50 %.

The 50% failure rate indicate that the Dental Drill product of Decfab Company is

not working up to the good quality marks which is one major cause of decline in

sales and quality issues in the Company.



8. What is the mean time between failures (MTBF) for the dental drill?

Mean time between failures or MTBF = 1/FRn

Where,FRn = Number of failures

Operating Time

Total time of the operation = 100 hours * 6 units

= 600 unit hours.

Non-operating time = 3*15 i.e. 45 hours for the 1st unit

+ 3*50 i.e. 150 hours forthe 2nd unit

+ 3*85 i.e. 255 hours for the 3rd

unit

= 450 unit hours.

Operating time = Total time – Non-operating time

= 600 – 450

= 150 unit hours.

Thus, FRn = 3/150

= 0.02 failure per unit hour.

So,MTBF or Mean time between failures = 1/FRn

= 1/0.02

= 50 hours.



9. What is the inherent availability of the dental drill for the dentist?

Inherent availability = Uptime/ (Uptime + Downtime)

Total Time = 600 hours

Uptime = 450 hours

Downtime = Total time – Uptime

= 600-450 hours

= 150 hours

Inherent availability = 450/ (450+150)

= 450/600

= 0.75

The inherent availability of the dental drill for the dentist is 0.75 or 75%.



10. Does DecFab have a problem with the dental drill wearing out prematurely? If

so, why? If not, why not?

Yes, The Decfab Inc. have problem with the dental drill wearing out prematurely

as 3 out of 6 samples fail during the test which is 50% of sample.

The mean time between failure rate is 50 hours, where the units was designed to

work for minimum of 200 hours and tested for 100 hours.



11. Develop and draw an Operating Characteristic (OC) curve for Mr. Hanson to

help with his sampling plan. Assume n=15 and c=0. Find the probability of

acceptance (Pa) for p (% nonconforming) of 1, 5, 10, 15, 20, 25, and 30 percent.

The Operating Characteristic Curve is useful to analyses the probability of

acceptance of a lot with respond to the defective percent. In the above graph it can

be said that the probability of getting accepted the lot is 0.8601 when the defect is

1% which reduces up to 0.0047 when defect is 30%.

It states that even a bad lot have the probability of getting accepted 0.0047 where a

good lot rejected 0.1399 (1-0.8601).

NOTE:- The probability values are taken from the Binomial Probabilities Table

where n = 15, c = 0.



12. Determine the producer’s risk, “a” and the consumer’s risk “b”, if AQL=5%

and LTPD=10%

Producer Risk = n! pr qn-r

r!(n-r)!

= 15! (0.050) (0.9515-0)

0!(15-0)!

= 0.4633

= 1 – 0.4633

= 0.5367

The risk of Producer is 0.5367 at 0 defects.

Consumer Risk = n! pr qn-r

r!(n-r)!

= 15! (0.050) (0.9515-0)

0!(15-0)!

= 0.4633

The risk of Consumer is 0.4633 at 0 defects.



13. Determine the Average Outgoing Quality Limit (AOQL) for the above

sampling plan.

The above graph shows the indifferent point between good and bad lot and the

average outgoing quality is 0.023165.

P Pac AOQ

0.01 0.8601 0.008601

0.05 0.4633 0.023165

0.1 0.2059 0.02059

0.15 0.0874 0.01311

0.2 0.0352 0.00704

0.25 0.0134 0.00335

0.3 0.0047 0.00141



14. How should Sue Wilson develop a total quality management (TQM) program

given the conditions which exist in the case? Describe some specific actions she

could take to improve quality at DecFab.

Sue Wilson can develop a TQM program by considering the following factors: -

Top management

commitment and

involvement

Customer involvement

Design products for

Quality

Design production

process for quality

Control production

process for quality

Developing supplier

partnerships

Building teams of

empowered employees

Benchmarking and

continuous

improvement



Top management commitment and involvement : -

As it is seen from the case that when Mr. Hanson manufacturing V.P. formed a

problem solving team to solve the problem of dental drill production process there

is a strong resistance from the department heads for the same. Also when Sue

Wilson tried to establish a stronger commitment to quality there is a great deal of

resistance among the managers, including John Baldridge. So there is no support or

involment of the top management for anything good implemented in the

organization. Hence, there must be stronger commitement from the top

management.

Customer involvement : -

It means the company must identify the customer’s wants and then incorporate the

wants into product design. So, it is nothing but giving customers what thay want.Thus, DecFab can use this tactic.

Design products for Quality : -

It means excellence in the performance, features, reliability, durability, appearance

and service are affected by the product design. So the product design must be of

quality one and that which is based on what the customers need. So, DecFab must

accordingly design its products.

Design production process for quality :

Machinery and workers play an important part of the production process so it must

be designed to produce the products with dimensions of quality that the customers

want. So, DecFab must redesign its production process.

Control production process for quality : -

It means DecFab must exercise continuous monitoring and control on the production process to ensure that only products of superior quality are produced.

Developing supplier partnerships : -



It means DecFab must select and develop suppliers that fits into the TQM system.

DecFab must try to develop long term relationships with the suppliers so that they

deliver parts of perfect quality which the customers want.

Building teams of empowered employees : -

It means the company must train, organize, motivate and empower its employees

to produce and extend the availability of products and services of perfect quality.

Benchmarking and continuous improvement : -

It means DecFab must set certain standards or benchmark of comparison withrespect to its competitors to measure the progress and performance on a continuous

basis as well as take corrective actions whenever possible.

Specific actions that Sue Wilson can take to improve the quality at

DecFab :

o Sue Wilson can make use of Quality function deployment tool for

identifying customer wants and eliminating wasteful product features and activities

that do not contribute to product quality. Through this tool she can identify the

product features that need improvement.

o Sue can form Quality Circle (QC) i.e. a formation of group of employees

who will meet on a regular basis to undertake work related projects designed to



improve working conditions, self-development and to advance the company by

using the quality control concepts.

o Sue Wilson can make use of certain Statistical process control tools like

Pareto diagram and process flow diagram to identify the most important problems,

find out the percentage of defectives in the process, eliminate them and improve

the efficiency of the production process.

o Sue can make use of various control charts like Run charts to find out

whether the production process is within the control or not and take corrective

actions as soon as possible.



15. Describe a course of action for the Problem-Solving Team, in addition to that

mentioned in the case.

The problem solving team can take the following actions : -

There is a lack of communication between departments regarding marketing,

designing and production of any product, so the communication gap must be filled

up first by arranging some training programs or programs that aims to improve

communication skills.

They can conduct Quality Audit by appointing a quality control inspector

who can do the inspection of the entire unit or control the production process.

Proper training programs can be arranged for the employees and workers

regarding how to work efficiently.

They can arrange seminars or workshops for creating or encouraging more

and more interests in work for workers and employees.



They can organize visits to some good companies plant for analyzing how

they operate, how they carry out all activities efficiently, how there production

process is, how they maintain their quality levels etc.

They can set certain standards or benchmark for the production process and

do continuous comparison of the actual performance with the standards set to find

out the deviations or defects.

The major problem here lies with the poor machining issue which is internal

problem, so regular repairs and maintenance or checking up of all machines i.e.

whether they are working at their fullest capacity or not is necessary.

The second important problem is bad incoming parts. Here DecFab adopted

bidding system in the past for giving contract to vendors but they must give

contract to them on the basis o f the information they have gathered about that

vendor, his reputation in market, quality of his parts etc and not just on the basis of

lowest cost of the bid.

So, we think that if these above two problems are solved as soon as possible then

DecFab can definitely become a well known brand in the market among the

customers as it was in the past.

Tqm Case Decfab Inc.

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