g8d - Lamp Case Study
g8d - Lamp Case Study
g8d - Lamp Case Study
Creative
Lighting
Company
G8D Case Study
Introduction
This case study has been developed to further explain the application of Global 8D Problem Solving
(G8D), in particular it focuses on steps D3 to D7. As a reminder the steps in the G8D process are
defined as: -
This case study will also cover specifically the use of the following tools and methodologies: -
Background
This case study has been developed around real events at a lighting design and manufacturing
company that we will call The Creative Lighting Company.
The company design and manufacture a range of domestic, utility, industrial and retail lighting
products. They are a relatively small company based in the UK with customers all over Europe.
This case study is used to provide a working example of how the Global 8D problem solving process
has been applied to what appears to be a simple problem in their paint plant.
Scenario
The Creative Lighting Company are making metal lamp shades for the domestic market. These are
fabricated from two spinnings which are press fitted together and then painted using a robotic powder
coat paint plant in several colours (spinning is a process for making cylindrical forms over a pre-shaped
former).
These are then assembled with a lamp holder, metal reflector and mounting arrangement for ceiling
and/or wall mounted application.
2
www.resultsresults.co.uk
G8D Case Study
Some of the blue finished product has a defect, paint runs on the top flat. This has been occurring over
the past few weeks.
Flat
The paint plant is a powder coating plant. Powder is positively charged through robotically operated
spray guns that are mounted in shuttle booths, one for each colour and one for special colours.
The product is manually hung on the conveyor (that runs continuously) using specially designed hooks.
After each paint run the hooks are dipped in a solution to remove the old paint. The conveyor is
negatively charged to attract the paint and the metal hook serves to provide that electrical connection.
The following diagram gives a schematic of the paint plant area for information.
Drying
Then Creative Lighting Company had been making this lamp shade design for over 2 years when they
ran into this problem of a paint run on some of the finished product in one particular colour, blue. As
they do not make for stock, only to order for their retail outlet customers, this has an immediate
impact on their ability to meet current demand.
3
www.resultsresults.co.uk
G8D Case Study
After several attempts to resolve the problem themselves the paint plant team call in help from the
Process Engineer. She decides that this requires a more structured approach and employs the G8D
process to ensure they get to root cause and prevent this type of problem occurring again.
The Process Engineer has been asked the lead the G8D Team in their problem solving efforts and to
ensure that a customer representative is also made available to the team.
The team has been formed and includes members from Quality, paint plant, the Process Engineer,
Maintenance and from assembly (the internal customer).
The team discussed what had been done so far which included: -
Based on the facts available to them, the team then developed the problem description starting with
the problem statement – what is wrong with what.
Problem Statement: “Some of the blue finished product has a defect, paint runs on the top flat”. This
is what the G8D Team have been able to establish as a result of their initial investigations.
Having established a clear problem statement, the team now need to develop a problem description.
To do this the team used the Is/Is Not worksheet and completed it as follows.
4
www.resultsresults.co.uk
G8D Case Study
Where first seen After top coat applied Before top coat
The team then went and gathered further information from the paint plant and reported that:-
The team are now able to develop a problem description for the lamp shade as based upon the
information they were able to establish about the problem
Problem Description: “20% of the blue finished lampshades are consistently rejected for paint runs
on the top flat. Defects are not seen before the finish coat is applied”.
5
www.resultsresults.co.uk
G8D Case Study
Having established the Emergency Response Action (ICA) as 100% inspection the team looked into
various options, considering the following: -
The following was recorded by the team as part of their decision making process:
Get the blue finished by an existing Will meet customer Additional cost of £1.50 per 4
subcontract paint supplier need. item gives a loss on all blue
Will buy time to solve sales
the problem.
Rework and recycle all rejects through Additional product Needs to be done on 1
paint plant can be achieved. overtime as plant is at
Keeps the problem capacity right now
in-house
Paint the blue product using a wet Can do all needed Needs skilled labour from 3
backed booth normally used for and any rework of old development dep’t.
prototype and development work rejects Paint not as heat resistant
as powder coating
Having considered the options the team decided to recommend to rework the blue rejects in overtime
as the labour could be used on all other colours and only needs to be in attendance for the first 20
minutes of the process for loading onto the paint plant as they can be removed by the day shift on the
following day.
Possible Causes: Referring to the Is/Is Not worksheet, the team first used the Differences and
Changes worksheet to record what was different in, on or around the “IS” when compared to the “IS
NOT”
E.g. What is different on or around the (is) blue when compared with (is not) the black, white or grey
finished lamp shades?
6
www.resultsresults.co.uk
G8D Case Study
The team established a number of differences and these were recorded on the Differences and
Changes worksheet.
Then we need to ask the question “what has changed in, on or around the “IS”. Something must have
changed or the problem would have always been there. This must be factual so it’s OK to generate a
question log or ask a team member to go and find out.
A useful tool that can be used to record this information is a time line. A time line is used to record
all events in and around the problem. The team developed their time line having gathered all the
relevant details.
Roof leak
New staff New dryer
over plant
This time line clearly shows events that the team considered relevant to the problem with the blue
lamp shades starting with a new supply of hooks on the 15th February to the new electrical earth
installation on the 12th April.
This can be added to later in the process as more information and further understanding is achieved.
Having this and previous information the G8D team can now complete the differences and changes
worksheet
7
www.resultsresults.co.uk
G8D Case Study
Lamp shade hangs lower due to longer hooks The longer hooks were introduced with the new 22/12/2011
used to ensure paint thickness application paint specification for blue in late December last
year.
This shows the differences and changes around the problem and is driven from the information
gathered and the entries on the Is/Is Not worksheet.
The team then brainstormed possible causes of (problem description) “20% of the blue finished
lampshades are consistently rejected for paint runs on the top flat. Defects are not seen before the
finish coat is applied”.
Possible causes were then brainstormed by the team and they recorded the following:-
• Untrained labour
Having determined possible causes the team then developed a causal theory for each possible cause
and entered onto the Possible Cause worksheet seen on the next page.
NOTE: again this worksheet aligns with the previous 2 as the process is driven by the differences and
changes around the “IS” when compared to the “IS NOT”. Therefore the causal theories are developed
in line also.
8
www.resultsresults.co.uk
G8D Case Study
Develop rounded causal theories for each possible cause. First brainstorm the causes and
develop a rounded statement for each possible cause
A) • “Untrained labour have hung the lamp shades incorrectly leading to incorrect angle and paint runs
during the curing process”
B) • “Untrained labour touched some of the lamps during hanging. The grease deposited prevented proper
curing of the paint resulting in runs”
C) • “New batch of paint was of poor quality leading to unsatisfactory curing leading to paint runs”
D) • New hooks not fitting properly causing a poor earth and leading to paint runs due to poor adhesion and
curing properties
E) • Hooks for blue paint finish are longer than normal and are not fully immersed during cleaning. This leads
to partial removal of old paint leading to poor earth connection
F) • Clean-down during maintenance caused excess dirt in the plant leading to paint defects
NEW TEAM MEMBER: having developed the possible cause theories the team decided that they needed
some additional expertise in the team and requested that an engineers from production engineering
and maintenance attended the meeting to help with the next stage of the process.
9
www.resultsresults.co.uk
G8D Case Study
A B C D E F G H I J K
N N N Y Y N
Y Y
Y Y
Y Y
Y Y
N Y
NOTE: the possible root causes worksheet has been shrunk for the purposes of this case study.
Normally this would align to the Is/Is Not and other worksheets.
10
www.resultsresults.co.uk
G8D Case Study
The outcome of this exercise showed that possible cause E -“Hooks for blue paint finish are longer than
normal and are not fully immersed during cleaning. This leads to partial removal of old paint leading to poor
earth connection” – to be the most likely cause.
1. Inspect all the longer hooks in the paint plant and check for paint residue after the cleaning
process
2. Examine the cleaning process to determine if the theory could be proven regarding cleaning
3. Select “suspect” hooks and run a trial through the paint plant to see if all the blue lamp shades
developed the paint run after curing
4. Use the same hooks fully cleaned to see if the problem was not repeated
This was carried out later that day and the theory was proven and they were able to switch the
problem on and off again.
The G8D Team now had a verified root cause for the problem.
The team discussed with the paint plant the hook cleaning process and agreed that the depth of the
cleaning tank was OK provided that the cleaning fluid was kept topped up. Anything less that 90% full
meant that the longer hooks would not be fully immersed in the cleaning fluid.
The team ran a further experiment to determine how long before the cleaning tank fluid level dropped
below 90% but within the minimum level specified in the Standard Operating Procedure. They
concluded that this would take 6 to 8 working days to get below the 90% and a further 12 days to get
to the minimum level based on current activity levels.
Having established the verified root cause of the problem and escape point, the team met to discuss
what would be the most effective permanent corrective action and discussed and agreed the following
options: -
1. Design an alternative hook that would fall within the minimum cleaning fluid level
2. Increase the size of the cleaning tank to facilitate the longer hooks
3. Increase the frequency of cleaning tank cleaning and top up
4. Use an alternative cleaning method for the longer hooks (shot blasting or sub-contract cleaning)
5. Use disposable hooks
6. Develop the paint plant (spray booth) to enable the standard hooks to be used on the blue
finish
7. Change the SOP for the cleaning tank to revise the minimum level to 90%
11
www.resultsresults.co.uk
G8D Case Study
Each of these was investigated by the team and other members of the company and the following
was reported back to the team by the team leader and the production engineering department.
The team leader had reported to management the success so far with potentially solving the problem
and was provided with a number of criteria that the final solution needed to meet: -
*The number in brackets is a “score” of how important these are to the business.
The team used the decision making worksheets to establish which ERA proposal to take forward. This
activity is summarised in the following table.
12
www.resultsresults.co.uk
G8D Case Study
Given the failure of all but 2 proposed ERA’s, the team agreed to proceed with: -
Installing a larger cleaning tank – to ensure all hook sizes would be fully immersed and
therefore properly cleaned (ERA for root cause)
Change the SOP for the cleaning tank to include a regular depth check twice for every shift
(ERA for escape point)
The team drew up a full plan and included all the necessary disciplines from the company in the
meeting. These included production engineering, health and safety, maintenance and process
engineering in the form of the team leader.
Monitor paint quality by having a daily report on all quality issues to ensure problem remained
solved
Earth testing kit provided for sampling all hook connectivity every hour which was recorded and
reported each day
Developed an operator level check graph that was monitored by the paint shop supervisor and
measured
Cleaning fluid level twice a day
Cleaning fluid cleanliness at the beginning of each shift
Sample visual check of each type of cleaned hook
The SOP was up-dated to include this and the operators were trained
13
www.resultsresults.co.uk
G8D Case Study
D7 – Prevent Recurrence
The extended team came together to determine the root cause of the root cause for both the problem
and the escape point.
It was discovered that the cleaning tank was not considered as part of the induction process and that
the operators were not aware of the importance of using only completely clean hooks.
1. All new product introduction should be signed off by process engineering as well as production
engineering and production management
2. All operators were trained on the principles of powder coating and the key factors to be
monitored
3. The induction process for new operators in the paint plant to include a training period on paint
plant operation and/or cleaning tank operation
NOTE: For further information on the use of all the worksheets and methodologies, please see the
“Global 8D Problem Solving with Results” workbook.
Graham Cripps
ResultsResults.co Ltd
www.resultsresults.co.uk
14
www.resultsresults.co.uk