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Anonymous Poster

how do i do the cause and effect diagram for these problems ?

11/14/2008 4:53 PM

Hellow I need help for an assignment that i`m strugling in , the case study is in donna C.S. summers text book ( quality text book)

its about a simplified version of a bracket used to hold a strut in place on an automobile. welded to the auto body frame, the bracket cups the strut and secure it to the frame with a single bolt and a lock washer. proper alignment is necessary for both smooth instullation during assembly and future performance. for mounting purposes the left side hole must be alligned on center with the right side hole and the angle between hole centers will equal to zero , the bracket is created by passing coils of flat steel through a series of progressive dies. as the steel moves through the press , the bracket is stamped, and finally bent into appropriate shape , recently the customers have been complaining about having difficulty securing the brakcet closed with the bolt and lock washer . the bolts have been difficult to slide through the holes and then tighten. Assemblers complain of stripped bolts ans snug fittings. the problem -solving cycle begins with "Recognizing the problem and estabshlishing pritorities." Bracket customers have made management at WP Inc.((the company)) well aware of the problem.Because management is unsure of the root cause of the problem , they proceed with the second step of problem solving and assemble a team

. the team consists of representatives from process engineering, materials engineering , product design and manufacturing. beginning with defining the problem , the team has decided to brain storm the reasons why this problem has occured

the team decided to develop performace measures to answer ,the problem is Difficulty securing brakets closed wuth bolt and locknut !!! ANd the assignment is about creating a cause and effect diagram and brain storm potential root causes for the problem . actually i know how to do the diagram but i have No idea what are the causes of the problems ! have u got any idea !!

and the other assignment is about doing another cause And effect diagram Ans the problem in the 2nd part Is that the most likely cause of the problem is experienced by customer is alignment of the holes at some stage of the formation process where the holes end up off center So here we i should do another cause and effect diagram about the root causes of improper hole alignment So have u got any idea about the causes please help me !!

In brief ,

its about doing 2 Cause and effect diagram ((fish Bone diagram)) and brainstorm potential root causes for these problems:

1- difficulty securing brackets closed with bolts and locknut

2- improper hole allignment ((knowing that after doing the first cause and effect diagram , engineering determine that the most likely cause of the problem experienced by the customers is the allignment of the holes

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Guru

Join Date: Jul 2006
Location: "Dancing over the abyss."
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#1

Re: how do i do the cause and effect diagram for these problems ?

11/14/2008 9:38 PM

We generally don't respond to homework questions; however, we will guide your thinking about how to approach your assignment.

A cause and effect diagram is designed to help you break down a process into logical areas. Also called an ishikawa of fishbone diagram.

The logical areas are man machine materials and methods. Ignored but implied are environmental factors that create the "state space" in which the diagrams process exists. So what could the Material aspects be that affect the fit and thus the installation? What if it is wrong material, wrong gage, wrong temper, etc? same with the Machine- correct die set? mounted on machine properly? correct punches? is lube working? correct lube? etc? There are literally a hundred questions that an experienced practitioner could ask for any one of the M's- man machine, material method

The cause and effect diagram is a good tool, BUT IF YOU LACK PROCESS INSIGHT, it really will only help you list possible areas to investigate, not bring you to a root cause. If you don't know that the material has different tempers for instance, you'll never figure out why the stuff just doesn't bend right.

Take a break, and on a sheet of paper right down what you think the right things are needed for each of these M's, then put the ones that you suspect could be out of whack on your chart.

A better approach than the cause and effect diagram is the five whys stairstep diagram.

Ask whats wrong with what? - inyour example :

Bracket doesn't align and assemble easy

then ask why four more times:

Bracket doesn't align and assemble easy

why? holes to small

why? wrong punches in die

why? couldn't find right punches?

why? they were broken

why? the lube sprayer was clogged

why? purchasing bought cheap lube

why? crooked salesman took him to footbal game

why? because he couldn't get the order based on quality or price.

Root cause- failure to have policy forbidding purchasing agent from taking gifts.

This could be done a countless number of ways

While its called the 5-whys? in my experience i just keep asking why until I get to the management failure- because it is MANAGEMENTS responsibility to have things run right. If it ain't running right, something management did or failed to do is likely implicated. And by the way, I was plant manager as well as quality manager. Ask why til you get to management.

now you do it to answer the why are bolts stripping making assembly difficult. really pretty eay to figure...

milo

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People say between two opposed opinions the truth lies in the middle. Not at all! Between them lies the problem, what is unseeable,eternally active life, contemplated in repose. Goethe
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Member

Join Date: Jan 2008
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#2

Re: how do i do the cause and effect diagram for these problems ?

11/15/2008 10:40 AM

This sounds to me as though you have already utilized what the results of a cause and effect exercise will reveal, and now you should move into the process of performing a DOE (Design of Experiment) and in this process with the correct inputs you will generate a math model (regression analysis) for each, or the other information that will point you in the correct direction.

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Member

Join Date: Jan 2008
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#3

Re: how do i do the cause and effect diagram for these problems ?

11/15/2008 10:45 AM

I have a power point presentation on this but a (DOE) could get very involved.

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Participant

Join Date: Nov 2008
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#4
In reply to #3

Re: how do i do the cause and effect diagram for these problems ?

11/15/2008 3:38 PM

really ! i`ve just finished from doing it on the power point . what is (DOE) i`d be glad if i can see ur presentation and compare it with mine

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Participant

Join Date: Nov 2008
Posts: 2
#5
In reply to #4

Re: how do i do the cause and effect diagram for these problems ?

11/15/2008 3:47 PM

sorry its clear , actually its a case study that is required , and the subject is QUality

i study industrial engineering and its my 3rd year thank u very much indeed

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Anonymous Poster
#6
In reply to #5

Re: how do i do the cause and effect diagram for these problems ?

11/17/2008 5:28 PM

On the assumption that re-aligning the axis of the bolt with the axis of the holes (and vice-versa) is self-suggesting..., then consider replacing the bolt with a sufficiently durable toggle-bolt with an appropriate number of shock-absorbing washers between all contact surfaces through which the bolt passes, from bolt-head to bolt-toggle...

Then "chalk it up" to out-of-date testing of field-conditions, vibration, fatigue, material specs, etc...

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Guru

Join Date: Jul 2006
Location: "Dancing over the abyss."
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Good Answers: 243
#7
In reply to #6

Re: how do i do the cause and effect diagram for these problems ?

11/17/2008 5:50 PM

I would like to point out that The point of the exercise is to use a cause and effect diagram to drive a process to determine failure mode.

Suggesting that a single assumption is operant here, 'Axis of bolt out of alignment with axis of holes' with no explanation of "why" misses that point. Stating that it is just correct, by assumption and that the other factors merely need be "chalked up" to "whatever", looks quite clever but defeats the purpose of the project.

If the root cause was wrong material or failure to anneal, this answer would get a disappointing grade .

The point was for the student to gain experience in using the cause and effect diagram. How does handing him a single assumption help with that goal?

Perhaps they are off axis; perhaps the holes are too small thus stripping threads; perhaps stamped material workhardened, making it able to strip threads; maybe bolts are too soft or threads were machined rather than rolled and thus easily stripped.

Student will not get these insights by "assuming."

They need to work the damn diagram and think. Ask better questions (How could material cause threads to strip? How could threads be stripping now rather than before? What changed?)

Cause and effect is a process that teaches, not a guessing game. Parts changers learn nothing as they fry yet another part in their efforts to "fix something" Well, that didn't work, must be something else.

Problem solvers look deeper, trying to find the answer to why?

Its a discipline, not an assumption.

If the bolts and holes are off axis. Why?

WHy?

WHY?

WHy? Why?

The object of this exercise was to teach the cause and effect process. Thats why I contributed; not to give a right answer. its about the process. Its not to answer homework questions. Lets help by teaching.

milo

__________________
People say between two opposed opinions the truth lies in the middle. Not at all! Between them lies the problem, what is unseeable,eternally active life, contemplated in repose. Goethe
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Anonymous Poster
#8
In reply to #7

Re: how do i do the cause and effect diagram for these problems ?

11/18/2008 2:16 PM

Aren't students supposed to make assumptions, based on their current level of knowledge, then test those assumptions in order to gain experience and "background", and subsequently achieve understanding above and beyond mere knowledge?...

There must have been some semblance of a example exercise in the class textbook, and/or presented by the professor/teaching-assistant, from which to extrapolate a simple understanding of the cause-and-effect-diagram process required by the assignment in question. Why does the original poster (stumble) over the basic issue, and not, instead, have a more specific question about a more specific feature of the process?...

Also, spending the time, money, effort, and resources by convening a team, to conduct a study, to write a report, to solve what sounds like a relatively simple issue is the academic/governmental/bureaucratic type-of-approach to wasting the Company's money. While it is for an academic exercise, in this case, real-world industry is supposed to be concerned with promoting problem-solving leadership potential, when and if demonstrated, to higher levels of leadership, instead of indulging over-promoted management pretenders to even higher levels of over-promotedness, as tends to be the case in government, etc., isn't it?...

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Participant

Join Date: Mar 2012
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#9
In reply to #8

Re: how do i do the cause and effect diagram for these problems ?

03/04/2012 2:39 AM

Do you mind sharing your finals diagrams with us ? for the benefit...

if possible i'd like to have a copy, am working on something similar!

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Participant

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#10
In reply to #3

Re: how do i do the cause and effect diagram for these problems ?

03/04/2012 2:47 AM

can you provide me with that presentation ?!

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