Statistical Quality Control (SQC)

Under Supervision Of Prepared By Prof. Hamdy Elwany Shady Rashed

General Overview &

Six Sigma Application Example

1) Overview (About SQC in General) .

2) Reasons For Using SQC .

3) SQC Categories .

4) SQC Categories briefly .

5) Source Inspection .

6) Six Sigma Application Example (DMAIC) .

Presentation Contents

Overview .. • Product defects are most observable for

products that are mass-produced. In addition, product defects are more significant in manufacturing companies that are not so keen in controlling the quality of their products. If manufacturers want top quality products, measures should be taken in ensuring that product quality is maintained from the beginning of the production process until the end of the production line.

• Other manufacturing companies even guarantee the quality of their products way beyond after the products are purchased. As such, these companies offer warranties for their products because these companies are confident that their products are of excellent quality.

• One way of ensuring quality control is integrating quality into the process. Every process should be critically considered and guarded against errors that lead to product defects. However, in reality it is difficult to impose product inspection along every process- so much more if the production is quite large. This is why the task of maximizing the ability to control the quality of the products has become a challenge for most manufacturing companies.

• Fortunately though, This dilemma is addressed by the application of Statistical Quality Control in measuring and evaluating the quality of the products.

Overview ..

Reasons For Using SQC

1. The production processes are not perfect.2. The Need of Making products functional and

defect-free by correction with a deterministic solution.

3. Reduce the variation into the some product characteristics, which needs probabilistic models and robust statistical techniques to analyze quality of such characteristic.

4. Reaching the high levels of quality compared with same companies in The Industry.

5. Helping Evaluate and control Outputs (Products).6. Meet Customer requirements (High Quality).

There are three categories in statistical quality control, and each of these categories is effectively used in product quality evaluation .. ..

1. Descriptive Statistics

2. Statistical Process Control

3. Acceptance Sampling

SQC Categories

Descriptive Statistics

Statistical Process Control

Acceptance Sampling

In this SQC category, quality

characteristics and

relationships are described,

In order to achieve these, it is important to find out the mean, range,

standard deviation, and measure of the distribution of the data of the

sample.

This category verifies if a process is

functioning properly or not. A random sample of the products is taken, inspected,

and decided if these manifest characteristics that fall into a predetermined

range. The

predetermined range determines if the process is functioning or

not.

This category determines if

a product batch is

acceptable or not. If the

products are not

acceptable, then the

whole batch is rejected.

SQC Categories briefly …

Source Inspection

The act of monitoring or observing a process, procedure, or service that usually involving sampling and related sampling plans to insure compliance with the operational definition and to insure that all customer requirements or internal prerequisites are meet.

Ford Motor Company

(%) Driving Down Defect Rates (%)( Using 6σ Statistical Tool )

Six Sigma Application Example

Ford Story with 6σ Initiative

“The goal at Ford is to present customers with a vehicle with a ‘Factory Fresh Look’ no matter where in the world they are located.”

It's a huge undertaking to deliver vehicles without exterior surface defects after they have been transported thousands of miles by truck, rail, and ocean carrier to dealerships around the world.

When you pick up your new vehicle at the dealership, you expect it to be free of exterior finish defects.

Consumer Requirement

Ford Motor Company Goal

Defect That Need Action

Identify Defect (Define)

Identify Defect ..Vehicles destined for export had transit protection film applied to horizontal surfaces. Transit protection film is a plastic sheet with adhesive on one side and a chemical-resistant material on the other side, designed to protect the vehicle's exterior on the journey from the plant to the US port and then throughout the ocean voyage to the distributor.

Defect Aspects (Measure)During transport, large portions of the transit film lifted away from the vehicle surface and damage occurred. Dirt and debris would become trapped between the loose film and the vehicle's finish, and the film would lash against the fresh paint and cause defectsWhen the vehicles arrived at the port, the port processors had only a few options before loading the vehicles on the ocean-bound transport vessels :-1. Wash the car (which often removed even

more of the film).2. Take no action and chance that more damage

would occur to the vehicle before arrival at the final destination.

3. Repair the film – although the cost of fixing the material was often more costly than the original application.

Analyze Defect Aspects (Analyze)After Defining and Measuring Defect , Ford Team knew that they had to take action.

The cost of repairs and the negative impact on customer satisfaction levels drove the company to search for a solution to the problem.

Use Statistical Tool ( 6σ )

Applying 6-Sigma (Improve)In June 2001, a Customer Driven 6-Sigma project team was selected to reduce exterior finish defects caused by the transit protection film on exported vehicles.

Two target test locations

One destination

market1. Ford

manufacturing facility in St. Thomas, Canada .

2. Their port processing facility in Delaware .

&

1. The Middle East region.

Step 1The team chose :-

Applying 6-Sigma ..Main Reason for Choosing The Middle East Region :-Black Belt and project leader, explained the decision, "We selected this market for our project because we knew that the extreme temperatures and difficult ocean transport conditions that our vehicles were exposed to during the journey would be a test for our processes. We knew that if we could reduce the defects under these extreme conditions, that our improvements would be robust enough to create positive results in less challenging environments."

Step 2Historical Data Usage :- Using data on film-induced defects from 2000-2001, the team produced a cause-and-effect diagram (fishbone analysis) to capture, categorize, and prioritize potential root causes of transit film-induced defects.

Step 3Processes Examination :-

The team examined the processes within production areas for potential causes of failure. At the plant level, they looked at many factors including transit film installation instructions, differences among operators and shifts, proper training of operators, type of transit film material used, and surface cleaning methods & several key variables were identified that influenced the defect rate, including :-1. Transit film material – they identified that

flexibility, adhesion, and re-adhesion properties were important.

2. Operator training and supervision.

Applying 6-Sigma ..

Step 4Identify Areas For Intervention :-

By using Design of Experiments (DOE) & MINITAB the team were able to screen , and understand how the factors interact and to identify areas for intervention and process improvement opportunities.

Applying 6-Sigma ..

Ford compared defect rates for :-1.Vehicles covered with existing transit

protection film.2.Vehicles covered with a new protection film.3.Vehicles without protection film.

Applying 6-Sigma ..The data showed :-

1.The data showed that the new material reduced transit film induced defects from 2.89 defects per vehicle to 1.29 .

2.Use of the new material also resulted in a significant cost savings since the new material was less expensive.

3.The group From plant operators that provided with improved training, better film installation instructions, and increased supervision will reduce the defect rates during analyzing the exterior surface defect rates upon arrival at the final destination point .

The Way to Defect-Free (Control)When the project started in June 2001, the original transit film-induced defect rate was 2.98, or almost 3 defects per vehicle. The 6-Sigma project team's work led to the following improvements :-1. Using the new material reduced defects to

1.29 .2. Using the new material PLUS adding

increased supervision and improved training reduced defects to 1.03 .Decisions That Took :-

1. No transit film was needed until the vehicle was prepared for ocean transport.

2. Applying the film at the port processing point as opposed to the manufacturing facilities.

Decisions Result :-1. The decision was made to move the transit film

application process from the manufacturing plant in Canada to the port processing point in Delaware. The minimum target savings goal for Six Sigma projects at Ford is $250,000. This project resulted in cost savings in excess of $500,000.

2. Since the results at the Delaware port were so encouraging, the same process changes have been proposed for expansion to 11 other facilities in the US by spring 2002, and transit film installation operations are being relocated from manufacturing facilities to port processing centers. The team also was able to develop ISO qualified process templates and put new process controls in place to control for export operations.

The Application Success (DMAIC)

Thank You ..