Design For Quality

Design for Quality: In the modern world product quality is not all about the quality or the production and operating costs of the item, but careful consideration has to be given to other factors including it’s use, safety requirements, ergonomics, recycling and disposal methods. Poor design of a product can result in faults and shortcomings just as often as poor production methods. The design process is critical when undertaking a new project or design for the commercial market. In order to achieve the standard required for this, it must be built in from the start of the design process and maintained throughout the whole production process. Although the design process takes up a lot of the allocated budget, it has been shown that 80% of faults and failure can be traced back to inadequate planning, design and development. Also, up to 60% of breakdowns that occur within the guarantee period are results of incomplete or incorrect product development. Therefore it is plain to see that ensuring quality and improving quality are vital in the design process, and must be tackled in a team based environment covering all areas in the product development starting with product planning and marketing. A systematic approach is encouraged in the overall product creation process starting from the project managers right down through the projects teams. The figure shown below shows an integrated product creation process undertaken by various project teams from different disciplines bringing together their collective knowledge and expertise in a specific area.

Figure 1 Product Creation and tracking processes (Engineering design) The type of arrangement ensures that the customer’s requirements are always at the forefront of the project and provides an environment where information is passed to the relevant parties efficiently and directly resulting in balanced assessments and the better decisions being made when it comes to achieving the required high quality. This assignment will look at one of the methods employed by designers to tackle these issues. Failure Mode and Effect Analysis (FMEA) Introduction: Failure Mode and Effect Analysis, or FMEA is a technique that has been around for over 60 years, but it wasn’t until very recently that it has gained widespread appeal throughout the world (“due to it being incorporated very successfully by the North American automotive industry. A standard (QS-9000) was introduced which required suppliers to carry out FMEAs in an attempt to cut down or eliminate failures before they happened.”) The advantages and the appeal of this method over others was that it does not need pages and pages of statistics to significantly increase the profits of a company along with reducing the litigation costs resulting from faulty goods. [1] Engineering design

FMEA Explained: An FMEA can be described as a systematic method of identifying and preventing product and process problems before they actually occur. The main focus of FMEAs are to limit or avoid risk, whilst preventing defects, enhancing safety and increasing customer satisfaction. Ideally they should be carried out in the creation stage of the project design or during the development stages where it is easier to take action and overcome any issues, but this method can also be applied to existing products to increase performance of a company. [2] basics of FMEA A good FMEA will: •

Identify known and also potential failure modes.

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Identify the cause and effect of each failure mode.

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Prioritise the failure modes identified according to the risk priority number (RPN), which is the frequency of occurrence, severity and detection.

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Provide corrective action to take place.

The history of FMEAs The FMEA discipline idea has been around since the late 1940’s where it was developed by the US military and then used in the aerospace industry to develop rockets. Because of the high costs involved in developing this technology it was deemed necessary to use a system that would reduce or eliminate errors resulting in cost saving of this expensive technology. The main use and widespread acceptance of this method came during the 1960’s when NASA were trying to put a man on the moon. The first major company to adopt this method was the Ford Motor Company in the 70’s after it was involved in a scandal when defective and potentially lethal cars being sold to the public. The defects were blamed on poor design planning and so their whole system was overhauled to ensure this would not happen again. Today there are several different types of FMEAs used globally. The different types are listed below: •

Software - Main focuses are on software functions.

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Process - Main focuses are on manufacturing and assembly processes.

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Design - Main focuses are on components and subsystems.

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Service - Main focuses are on service functions.

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System – Main focuses are global system functions.

Conducting an FMEA: There are two ways in which a FMEA can be carried out. The first is using historical data gained from analysing similar products, warranty data and customer complaints records to identify failures. The second method is by using mathematical models, simulations, inferential statistics, concurrent and reliability engineering to identify and define the failures. Both methods are perfectly acceptable providing they are carried out accurately and properly, and will provide the user with practical and useful information that will reduce the risk load in the design, system, process and service. Customer satisfaction is the main priority of any company, so the quality of the products and services have to be at their best possible. This can only be achieved by the constant every day and ongoing improvement in quality. There are three key characteristics or measurement indicators that can be used provide feedback to the process producing opportunities to correct quality issues. 1. Leading Characteristics: This is a measure of quality that can be accessed and analysed before the product or service is delivered to the customer. 2. Intermediate Characteristic: This is a measure that can be accessed and analysed after shipment of product, but before it reaches the customer. 3. Lagging Characteristic: This is a measure that can be accessed, analysed and modified to meet the customer’s satisfaction after it has been delivered. Who should conduct an FMEA? An FMEA should never be carried out on an individual basis because of the complexity and variation of each specific project. A team must be made up of an array of crossfunctional and multidisciplined people because the knowledge that is required must come from many specialised sources.

Process of FMEA: As mentioned previously the main priority of an FMEA is to identify and prevent known and potential failures from reaching the customer. In order to achive this some assumption need to be made including prioritising one problem over another. The three main components used are: 1. Occurrence – Frequency of the failure. 2. Severity – Seriousness of the failure. 3. Detection – Ability to detect the failure before it reaches the customer. A numerical scale is used to define the value of these components, called a Risk Criteria Guideline